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- . E. CANNON - M?PARATUS ?FOR CONTROLLING THE SLIDE MOVEMENT ' 2,405,640 IN LONG-BED HYDRAULIC PRESSES Filed 'May '15; ?1943 4 Sheets-Sheet? 1 lNVENTbR' ?$924 Can/Mo? -? ?BY $753 gATTORNEYS щ: . Aug. E3, 3946. ╗ E. CANNON ZAQE?QO - APPARATUS FOR CONTROLLING THE SLIDE MOVEMENT IN LONG-BED HYDRAULIC PRESSES '. I Filed May 15, 1943. ' > 4 Sheets-Sheet 2 F96 BY 'J /g A - ' ~ TTORNEYS 71%?, 91%. E. CANNON APPARATUS FOR CONTROLLING FTHE SLIDE MOVEMENT IN LONG-BED HYDRAULIC PRESSES Filed May 15, 1943 - 2Aо5?во 4 sheetswsheet 3 a" -K?53 I 70 9 66 67 з '1 i I l I l . .INVENTOR F? a щ (9' ? BY . ? ? -.F/?EZ Can/MOM? ~ ? ' ATTORNEYJ ' - 4 E. CANNON ~ 2,405,640 , APPARATUS FOR CONTROLLING?THE SLIDE MOVEMENT IN'LONG-BED HYDRAULIC ,PRESSES Filed May 15, 1943 ' _ I 4 Sheets-SheetA _ ' INVENT0R4 Patented Aug. 13:, 1946 UNITED STS PTNT 2,405,640 APPARATUS FOR CONTROLLING THE SLIDE, MOVEMENT IN? LON G-BED HYDRAULIC PRESSES Earl Cannon, Rockville Centre, N. Y., assignor to E. W. Bliss Company, Brooklyn, N. Y., a corpo 1 ration of Delaware Application May 15, 1943, Serial No. 487,106 25 Claims. (01.,100-71) 2 This invention relates to improvements in ap paratus for controlling the slide movement in long-bed hydraulic presses, and more particular ly relates to self-modifying controlling means for maintaining the slide of such a press substantial ly in parallelism with the press bed during the ad vance or closing movement of said slide despite any die or blank irregularity which might tend to induce tilting of the slide. the provision of electrical compensating means which are initially rendered effective to commence compensation in the volumes of liquid supplied to several such advance chambers in response to a slight departure of the press slide from par allelism and to give to such controlling means a self-modifying eifect, rendering the compensat ing means eiiective only to the extent necessary to offset the effect of the forces tending to up Any reference in the following speci?cation and 10 set the parallelism of the press slide, so that rock claims to ?parallelism? or ?non-parallelism? is ing of the latter during its advance stroke may intended to relate to the attitude of the press slide relatively to the bed of a press. ?Substantial parallelism? is intended to include a minor de be obviated or minimized. A further object is to provide a self-modifying compensating arrangement, of the character men tioned in the preceding paragraph, which is sim ple and highly sensitive, both in responding to gree of non-parallelism which is within permis sible practicable limits. The term ?long-bed hy draulic press? refers to any hydraulic press non-?parallelism of the press slide in commenc wherein the present invention may be employed ing its compensating e?fect and in limiting the advantageously to maintain such substantial par degree of compensation to that which will cause allelism. 20 the press slide to advance with little or no rock In my co-pending Patents 2,353,388 and ing effect. 2,353,339, issued July 11, 1944, there are disclosed The foregoing and other objects are achieved electrical means, for maintaining substantial par according to the present invention by providing allelism of a slide of a long-bed press, wherein a compensating pumping mechanism which may contro1 is exerted to e?ect compensation in the 25 be automatically adjusted to vary the relative vol volumes of liquid delivered to ram advance cham umes of liquid pumped to ram advance chambers bers toward opposite sides of a long-bed press. toward oppositesides of a press slide; controlling In the embodiments illustrated in the said co means responsive to non-parallelism of the press pending patents, only two diiierent stages or de slide and adapted to initiate a change in the adjustment of the said pumping mechanism to grees of compensation are provided. This ar rangement usually affords somewhat more or less cause the latter to eiiect a compensating varia than the precise compensation required in a par tion in the delivery of liquid to said chambers; ticular case, and, hence, the compensating e?ect and control-modifying means coacting with said may be intermittent during the down stroke of the controlling means ?to limit the adjustment there press'slide, thereby causing the press slide to pur 35 of to that adjustment under which the press slide sue a rocking motion during its advance move will be caused to continue its advance movement ment, all as may be understood from the said with little or no rocking movement. patents. More speci?cally, I provide a continuously-act There are distinct advantages in employing ing, reversible, variable delivery compensator electrical means to achieve such compensation in pump arranged so that it may increase the vol the delivery of ?uid to advance chambers at op ume of liquid supplied to one ram advance cham posite sides of a press slide, and in most cases it ber relatively to the volume of liquid supplied to would be highly desirable to fully or at least sub ? the other; two photoelectric cells or switches ar stantially eliminate the mentioned rocking mo ranged so that one or the other becomes activated tion. or closed upon even a slight departure of the An important object of the present invention press slide from parallelism; a reversible electric is to provide electrical compensating means which motor, controlled by said cells or switches and may yield compensation in the Volumes of liq adapted to reversibly vary the control of said uid supplied to ram advance chambers toward op pump; and a mechanism actuated by the said re posite sides of a hydraulic press slide to an ex tent which Will cause the slide to pursue its ad vance movement in a substantially unchanging versible electric motor, which mechanisms, after the proper pump adjustment is attained yielding uniform advance movement of the press slide, is adapted to close olT light from and thus de-acti vate the mentioned activated cells, or to open said and substantially parallel attitude with respect to the press bed. Another important object of the invention is 55 " switches whereby to stop said motor and thus 2,405,646 3 4 terminate the variation in the compensator pump adjustment at the proper point to derive con tinued compensation which will enable the press slide to continue its advance movement in sub through pipes 30a, 38b, and discharge liquid through pipes 31a, 3ib, and through the valves stantial parallelism. pipe lines 32a, 32b, to e?ect an advance or closing movement of the press slide, or into return cham bers 2m and 2H), which are, respectively, served by pipe lines 33a, 33b, to achieve the return or 23a, 23b, either into the ram advance chambers 20a and 2%, which are, respectively, served by _ For the purpose of illustrating the present in vention, and without limiting the invention there to, several preferred embodiments are shown in ? opening movement of the press slide. The direc the accompanying drawings, in which: Figure 1 is a perspective view illustrating the 10 tion of stroke of the press, of course, depends on whether the valve pistons are in their left posi application of either mentioned embodiment of tion, as shown in the drawings, to achieve the ad the present invention to a long-bed press; vance movement, or in their right position to Fig. 2 is a fragmentary top plan view of the achieve the return movement. If the said pistons press and certain portions of the apparatus shown? are in their mid-positions, the liquid charged into in Fig. 1; the ?valves 23a, 231), instead of being pumped to Fig. 3 is a sectional view of apparatus compris the ram chambers, passes through interior pas ing a ?rst embodiment of the invention, taken sages (indicated in broken lines) in said pistons, substantially cnthe lines 3?3 of Figs. 1 and 4 whence it returns to the tank through pipe lines and illustrating the use of photoelectric cell as semblies; 34a, 34b. . in design, it will be appreciated that, where re sistance to the advance of the slide is not uni _ Fig. 5 is a diagram illustrating the various com ponent parts of said ?rst embodiment of the in vention and the interconnectionof said parts; and Fig. Gisa fragmentary elevation, partly broken away, looking down on certain important parts of a; second embodiment including limit switches which may lee-employed instead of the photoelec tric cells illustrated in the ?rst mentioned em bodiment of the invention. . General structure of press with? which the inven ' tion is illustrated ' ' , Although the pumping systems for operating the rams 18a, lSb, may be substantially identical Fig.~ 4 is a vertical sectional view taken sub stantially on the line 4-4 of Fig. 3; 25 formly distributed thereover, the different slip pages in the two pumps, slight leakages, and pos sibly other factors, may cause the side or end of the press slide encountering the least resistance to advance ahead of the other side thereof, and this uneven advance or cocking of the slide in many instances maybecome more pronounced as the slide progresses toward the end of its advance stroke. This highly undesirable cooking of the press slide may be substantially obviated by com Referring, ?rst, to Fig. 1: The press with which 35 pensating means nowto be described in detail. ?The compensating pumping mechanism thelinvention is illustrated may comprise a long bed ll provided in a base 12- suitably'tied at its .According to the present invention, it is pre ?opposite. ends toa crown I3? by tie-rods 14 ex ferred to provide a compensator pump 35 which tending through slide housings 15 which serve, at least partially, to guide a vertically reciprocating 40 may be connected in various ways to achieve the effects of the operation hereinafter set forth. In slide l6, and to suitably space apart the said crown the disclosed embodiment, the said pump is con and bed. and to maintain the two latter members nected by a pipe 36a to the pipe 32a which carries ?xedly in their proper relationship. Tie-rod nuts the liquid supply to ram advance chamber 20a, I?! preferably are providedat the upper and lower and is connected by a pipe 35b to the pipe 32b ends (the latter are not visible in'the drawings) of the said tie-rods. ? '3 _ The slide 16 is reciprocated inV-a' well-under-_ stood manner by rams l8a, [8b, ?xed symmetri cally upon the slide toward opposite ends thereof. which carries the liquid supply to ram advance chamber 201). y ' i The compensator pump 35, if connected in the manner just described, preferably should be a These rams, as best understood from Fig. 5, may 50 continuously-acting reversible pump, suitably driven as by an electric motor 350.. The pumping be enlarged at their upper ends to form ram pis mechanism of said compensator pump, further, is tons ltd, 19b, and may be urged downwardly on their advance strokes by liquid introduced into advance chambers 20a, 20b, and upwardly on their return strokes by liquid introduced into re turn chambers Zia, Mb. The said chambers, of the general character indicated in Fig. 5, may, of course, be suitably formed within the crown B of the press. . Separate, substantially identical, pumping sys-v tems are provided for handling the supply of liq-l uidjfor operating each of the rams I80, and l8b. These pumping systems function alike, and com prise suitably driven pumps 22a, 22b, and slide valves-23a, 231), which are constrained to func tion in unison ?by having their pistons 24a, 24b tied together by rods 25a, 25b, and turnbuckle 26. The said pistons may be held normally in their mid-positions by a well-understood spring centering device 21, and may be urged to the left and right, respectively, by solenoids 28a, 2812, which are connected in suitable electric circuits adapted to control the closing and opening of the press. , ' > Thesaid pumps draw liquid from a tank 29 preferably adjustable by movable means which extend to the exterior of the pump itself'for re .\ versing the flow of liquid through the pump and for controlling the volume? of such flow. Although. various types of pumps having pumping mecha nisms conforming to these preferred character istics may be used, a pump of the so-called ?Hele Shaw? type, such as is illustrated and described in my Patent 2,328,258, issued August 31, 1943, is well suited to the purpose of the present inven tion. ' Adjustment? of ?ow through the compensator pump As the particular pumping mechanism em ployed in the compensator pump is not an essen tial part of the present invention, the said pump is not described herein in detail. It is sui?cient to observe, for present purposes that the ?ow of liquid through the pump 35 may be reversed, and the volume thereof controlled, by a reciprocating control member 31 which extends from the in 75 terior mechanism'of said pump to'the exterior 5 2,405,640 thereof and yields volume control substantially proportionate to the extent of its movement. The control member 3'? is operatively connected through a link 38, a bell-crank 39, and a link 40 to a traveling nut All which is threaded upon and adapted to travel along a suitably mounted screw 42 when the latter is rotated. The nut 4| is re 6 a conventional type is employed between the shafts 52 and 53, as shown in Fig. 3. As illus trated, it comprises bevel gears ?6i and 62 keyed respectively upon the inner ends of shafts 52 and 53 and meshing with bevel differential gears 63 which are mounted within a cage 64 upon studs 65. The cage 64, preferably, is so mounted strained against rotation by a ?xed guide rod M upon suitable bearings as to be capable of turn which extends through a suitable bore in said ing about the common axis of the shafts 52 an nut and is retained, at its ends, in supports 42a 10 53. ' which carry bearings accommodating the ends of It should be apparent that if the parallelism the screw 42. The several mentioned connections . of the press slide I5 is maintained as it descends, ' between the control member 31 and the nut 4! the shafts 52 and 53 move'in similar degrees are allpivotal connections, and the bell-crank is but in opposite directions, so that the rotation fulcrumed upon a bracket 44 which may be imparted to the differential gears 63 by the bevel mounted upon the body of the compensator pump gear 6| tending to turn the cage 54 in one direc 35. The screw 42 is constrained to turn with a tion is exactly counteracted by the rotation im worm-wheel "i5 keyed thereto, and the Worm parted by the bevel gear 52 to said diii'erential wheel is driven by a worm 45 suitably coupled to gears tending to turn said cage in the opposite and driven by a reversible, electric, pilot motor 41. direction. Hence, it results that while the slide A dual control is provided for operating the i5 moves downwardly in parallelism with the bed electric motor 41; ?rst, a control which starts the I l the cage 64 remains at rest. said motor in either direction, in order to initiate On the other hand, if the parallelism of the the adjusting movement of the control member slide it is not maintained as it moves down 31, as soon as the press slide departs even slightly wardly, one of the shafts 52, 53 turns to a greater from parallelism and, second, a control which degree than the other, thus, through the diifer stops said motor as soon as the control member ential gears 63 imparting a rotative movement to El is moved su?iciently to yield an adjustment the cage 55 in a direction and to an extent which of the compensator pump 35, which causes the depends upon the direction and extent of tilting latter to establish and maintain a compensating 30 of the press slide. e?ect which will cause the press slide to advance A movable shutter member, which may be in uniformly and without substantial rocking motion. the form of an opaque disc 66,.is ?xed upon the cage 64 by any suitable means as, for example, Initiation of adjustment of the compensator by bolts or rivets 61, so that said disc is rotated pump 35 with said cage in response to any departure of the press slide from parallelism. The differential The said ?rst control as employed in the illusw mechanism and the disc 66 preferably are en trated ?rst embodiment, comprises two similar closed within a drum-like casingli? having hubs electric circuits, one for control of the motor 41 in each direction. Although the motor 4'! may 89, which turn upon bearing members ?It?! in the be any one of various suitable types, it is diagram 40 form of bushings which extend about the shafts matically illustrated in Fig. 5 as having a shunt 52, 53 and are supported by the brackets 54, 55. There preferably are provided, within the casing winding 41a which may be in the stator of the motor. The mentioned circuits include photo 68, two similar photoelectric cell assemblies in electric cells 48, 49, which are respectively ar cluding related light sources, one of which as ranged in circuits of suitable ampli?ers 5%, 51, ' semblies is adapted to control a circuit operat the latter, respectively, being connected separate ing the motor 41 in one direction and the other ly to the coils of relays 55a, 51a. These relays, of which is adapted to control a circuit oper through their normally open contactors 55b, 55c, ating said motor in the other direction. In Fig. 3,? 51b, 510, control the flow and direction of iiow there is disclosed only one of said assemblies, lo of current through the winding lila from the two ' в cated below the central horizontal plane of the leads, indicated by a plus and a minus sign, com casing 65. Said assembly comprises a light source prising a source of electric energy. Contactors in the form of an incandescent lamp 49a: and the 50c, 510, also control unidirectional current flow photoelectric cell 49, which, preferably, are through the rotor of the motor Ill. mounted respectively within separate compart Means for controlling the passage of light to ments ll, 12 ?xed inside the casing 68. The ad the mentioned photoelectric cells are shown in jacent walls of said compartments are respec-, detail in Figs. 3 and 4 and in diagrammatic form tively provided with aligned radial slots 1 la, 12a, in Fig. 5. The relationship of said means to the adapted to permit passage of light rays from operating parts of the press may best be under the lamp 49m to the cell 49. The compartment stood from Figs. 1 and 2, from which it may be 12, the slot 12a, and the cell 49 of the assembly seen that horizontal cross-shafts 52, 53, carried are indicated in broken lines in Fig. 4. respectively at their inner ends in bearing brack The other of said cell assemblies, located above ets 5d, 55, mounted upon the crown is and also the central horizontal plane of the casing 68, may by suitable bearing brackets located near their be similar in all respects to the assembly de outer ends are arranged to be rotated in opposite 65 scribed in detail in the next preceding paragraph. directions by oppositely-facing, vertically-extend In Fig. 4, the cell 48 in said other assembly, the ing racks 58, 5?, which are secured at their lower said cell?s compartment 15, and the latter?s radial ends to opposite sides of the slide 56. These slot 15a are indicated in broken lines, thus mak racks, of course, move vertically with the said ing clear the relative radial positions of the two slide and turn the shafts 52, 53, through step~up 70 mentioned cell assemblies within the casing 68. gear train 58 visible at the left side of the press As best seen in Fig. 4, the opaque disc 66 is in Fig. 1 and a somewhat similar but oppositely provided with an arcuate concentric opening 16 acting gear train 59 as indicated diagrammati which is of such length that its ends, in what cally in Fig. 5. r may be termed a neutral position of said disc with A di?erential mechanism 55 which may be of 75 respect to the casing 68, may extend to pointsv 2,405,640 only minutely out of register with the slots in ?8 the drum 68 progresses to the point where the the two said assemblies so that with the said disc slots in both photoelectric cell assemblies are in in such neutral position no light may pass from neutral or non-registering positions relatively to the several incandescent lamps to the correspond the arcuate opening 16 in the disc 66. ing photoelectric cells. When the mentioned non-registering relation ship is reached the photoelectric cell which had Operation of means initiating adjustment 0')? the previously been activated to start the motor 41 compensator pump becomes deactivated, and the other photoelectric It will be seen that, with this arrangement, a cell remains deactivated so that the adjustment slight non-uniformity in the advance movement 10 thus established in the operation of the pump 35 .of the press slide will rotate the cage 64 and remains effective and the three pumps 22a, 22b ' the disc 55 carried thereby to some extent, thus and 35 function together to deliver uniform causing the areuate opening 16 to at least partly quantities of liquid to the ram chambers 28a and register with the radial slots in one or the other 29b in order to accomplish the advance stroke of of the mentioned cell assemblies to permit the 15 the press slide without permitting more than a passage of light to and cause the activation of permissible departure of said slide from abso one or the other of the cells d8, 49, depending lute parallelism. upon the direction of cooking of the press slide. In order to simplify Figure 5, the compart The activation of one or the other of said cells ments l2, 15, housing the cells 158, 49, are not completes a circuit through the related ampli?er shown therein. The said ?gure, however, ade 5B or 5| and related relay coil 58a and 51a in quately indicates the relative positions of the es sential parts of the several cell assemblies and Fig. 5, that the connections between the plus of the shutter arrangement whereby to render and minus leads, comprising the source of current the operation of the mechanism understandable. supply, and the shunt winding 41a and rotor of 25 The lamps 48:1: and 490:, of course, are connect a well understood manner. It may be seen from the motor 41 are established through the con taotors of the relay coils 50a or 5la and are so ed (in a manner not shown) to suitable sources of electric energy. arranged that when coil 50a is energized through gc'omzilete operation of press and the slide the activation of cell 48, the current passes movement control means through the winding 41a in one direction and 30 when coil 5 la is energized through the activation Although the operation of portions of the dis of cell 49, the current passes through said wind closed apparatus may be understood from the ing in the opposite direction, the current flow foregoing description, it should be helpful to re through the rotor being unidirectional. Thus, view the operation of the press and its control the motor 41 may be controlled to operate in the 35 ling means in its entirety. Referring particu proper direction to initiate movement of the pump larly to Fig. 5, it may be assumed that the press control member 31 to cause the pump 35 to pump _ is open and that the pistons 24a, 241), the cen liquid from the liquid supply of the ram chamber tering device 2'1, and the related solenoids 28a, at the faster moving side of the press slide to the 28b, are in central or neutral positions, and that liquid supply of the ram chamber at the slower 40 all other parts are in the positions indicated in moving side of the slide, to substantially equalize said figure, the motor 4? being inactive and the the volumes of liquid being pumped into the pump 35, although being continuously driven by two said chambers in order to prevent further its motor 35a, being in neutral adjustment under increment in non-parallelism despite non-uni which no liquid is passing through said pump formity in distribution of the forces resisting between the pipes 32a and 322). It may be as the advance of the slide. The connections of the sumed, also, that the die or dies in the press are cells 48 and 49 in the circuits controlling the of such irregularity as to present a greater resist motor 41' are, of course, so arranged that the op eration of the said motor will be in the proper di ance to the advance of ram 181) than ram lBa so that when a blank in the press is engaged be? rection to initiate such equalization.? 50 tween dies or pressing members carried upon the bed ll of the press and upon the press slide it, Limitation of adjustment of the compensator the left side of the slide it will tend to move downwardly in advance of the right side thereof. The press operator, to start a cycle of operation, A second control, which terminates the opera tion of the motor 41, comprises a rack 11 which ' may close an electric circuit through solenoid 28a, causing the latter, upon thus being energized, is preferably connected through a link ?i8 and a to shift the valve pistons 24a, 24b, in unison, to turnbuckle connection 19 to the arm of the bell the left to the positions shown in Fig. 5, thus per crank 39 which actuates the pump control mem mitting liquid from the tank 29 to be pumped by ber 31. The said rack is preferably guided by a the pumps 22a, 2227, through the valves 23a, 23b, guide member \80 which may be fixed upon the into ram advance chambers 20a, 28b, to move the crown l3 of the press. The toothed portion of rams [8a, Nib, downwardly; the liquid in return said rack is arranged to engage a toothed seg ment 8| integrally formed with or ?xed upon the ' chambers 240;, Hi), meanwhile, being exhausted . pump periphery of the drum 68. 7 , through pipes 33a, 33b, and through valves 23a, 23b and pipes 34a, 3419, into the tank 29. This second control functions to terminate the When the slide l6 reaches a point in its down operation of the motor 41 by reason of the fact ward movement at which it is opposed by the en that, as the operation of said motor modi?es the gagement of the blank between the dies or press adjustment of the compensator pump 35 it also ing members, the greater resistance offered to the actuates the rack 11 which turns the drum 68 in the same direction as the disc 66 had previously 70 further advance of the right side of the slide causes liquid slippage in the pump 2217, or other turned to start said motor. Thus, as the adjust conditions under which the ram chamber 20b ment of the pump 35 brings the compensating receives a somewhat smaller volume of liquid than action of the pump up to the point at which the is received by ram chamber 20a, so that the left discharge of liquid to the two ram advance cham side of the press slide moves downwardly in ad hers is substantially equalized, the rotation of 2,405,640 9 10 Vance of the right side thereof; and, unless? the during: the advance stroke of the press slide, the said pump substantially equalizes the volume of liquid e?ectively being delivered to the two ram mentioned. inequality of liquid delivery is rem edied, the cocking of the slide?becomes progres sively greater and highly objectionable and pos advance chambers. ', sibly dangerous. According to the present invention, however, at The mentioned stopping of the motor 41 occurs by reason of the fact that, as the bell-crank 39 the very inception of such cocking of the press turns, to move the control member 3"! outwardly, it also operates the rack ?ll which turns the eas slide, the rotation of the shaft 52, driven by rack ing 68 in the same direction (?clockwisely, as 56 in the direction indicated by the arrow 52a, becomes more pronounced or of a greater degree 10 viewed in Fig. 4) as the disc 66 previously turned in response to the departure of the press slide than the opposite rotation (arrow 53a) of the from parallelism; thus moving slots ?H a and 12a shaft 53, which is driven by the rack 57. In the into non-registering positions relatively to the manner already explained, this difference of? ro~ arcuate opening 16, whereupon the cell 49 be tation of the two said shafts immediately causes the differential cage 6t, and the disc 6%; carried 15 comes deactivated, opening the circuit through motor? 4'! and thereby stopping the latter. thereby, to turn somewhat, in a clockwise direc-? Assuming proper design of the various com tion as viewed in Fig. 4. As the relationship of the slot l2a to the arcuate opening 16 preferably ponents of the described apparatus, the motor ?ll, after initiating adjustment of said pump, is such that even a slight clockwise turning of the will stop at the time the said adjustment be disc 65 will bring said slot and Opening into at least partial register, it will be seen that as soon comes eifectiveto cause said pump to yield sub stantial equalization of the volumes of liquid be as cocking of the press slide commences, the turn ing of the disc 66 permits light rays to pass from ing? delivered to the two ram advance chambers. Inasmuch as the motor 111 starts immediately lamp 49m, through slot ?Ha, arcuate opening ?it, and slot l2a to the cell 49. Thus the latter is 25 upon even a slight departure of the press slide from parallelism, the pump 35 immediately com activated, thereby closing an electric circuit through related ampli?er 5| and relay coil tila mences to bring the volumes of'liquid effectively delivered to the two ram chambers nearer to to close contactors 55b, 5 i0 and establish a circuit through rwinding 47a and the rotor of motor ti, causing the latter to start operation, practically upon inception of non-parallelism of the press slide. ? ' uniformity; After such uniformity is reached, the one of the cells 48, 139, which had previously been activated, ?becomes deactivated and both ? cells then remain deactivated; also the adjust ment of the pump 35 remains in condition to The motor щl, upon closing of the mentioned maintain proper compensation unless further and circuit through winding Md, operates in the di rection which causes the worm-wheel 45 and the 35 different distribution of the vresistance of the press slide occurs during theremainder of the presumably ?right? threaded screw G2 to turn in advance stroke of the press slide. a clockwise direction, as viewed inFig. 1, thereby causing the nut M to move along said screw to If such further change in the distribution of ward the right and consequently causing the bell the resistance occurs, the resulting non-paral crank 39' to move the pump control member 31 40 lelism again turns the disc 66 to activate which outwardly; and the mechanism of the pump 35╗ ' ever of, cells 48, 49 will set in motion the de scribed means to again substantially equalize the and the hydraulic connections thereof are ?such that the mentioned shifting of the control mem volumes of liquid being delivered to the two ram ber 31 causes the said pump, to transfer liquid advance chambers. from the pipe 32a to the pipe 321?. _ In well designed apparatus, the automatic ad justment of the pump 35 is completed before the The purpose of this transfer of liquid is to com slidedeparts beyond permissible limits of non pensate for the di?erences of liquid volumes which parallelism and the subsequent uniformity of rate the pumps 22a, 22b, deliver to the chambers 20a, of effective delivery of liquid to the two ram 2%, as a result of the uneven distribution of re sistance to the advance of the press slide. If op posite cocking of the slide occurs, compensation, opposite to that just described, is similarly ini tiated by the cell 68 and related ampli?er 5i] and relay coil Sta and contactors 501), 560., which pass current through the winding 41a in the direction opposite to that just described to yield opposite operation of the motor ill and opposite operation of they compensator pump 35. The cell 43 is acti vated by light which may pass thereto from lamp 50 chambers causes the slide to continue its advance movement with little or no rocking motion while at all times remaining within permissible limits of non-parallelism. Upon completion of the advance stroke of the press slide, the solenoid 28a is deenergized and the solenoid 28b is energized by any suitable man ual or automatic electric circuit control arrange ment, thereby? shifting the pistons of valves 23a, 28b to their extreme ?right? positions, as a 482:, through slot ?iii-a, arcuate opening ?it, and 60 result of which liquid is pumped through said slot 15a. Obviously, if the operation of the motor 4'! were not discontinued at the proper time, the men tioned adjustment of the pump 35 would become too great, thus causing over-compensation which valves to the ram return chambers 2la, 2| b to yield the return stroke of the press slide, the liq uid in chambers 20a, 26b, meanwhile, being ex hausted through said valves and pipes 34a, 34b, to the tank 29. would result in the slide cooking in the opposite The lamps, 48:0, 4-9.1), preferably, are so con direction, whereupon similar but oppositely-act nected, in electric circuits (not shown), that they remain lighted at all times during the operation ing controls of the cells 48 and A9, functioning alternately, would cause the slide to advance with of the press. In the absence of some substan a rocking motion which the present invention 70 tial non-uniform resistance the latter may main seeks to avoid. According to the present invention, however, the operation of the motor ill may be discontin ued at the proper time to leave the adjustment of the compensator pump 35 such that, thereafter, tain its slight permissible non-parallelism during the, return stroke of the press slide because of the equality in the volumes of liquid being pumped into chambers 21a, Zlb and because of the fact that the liquid passing through pump 35 courses 2,405,640 1l 12 freely from the tank 29, ?through the valves 23a, should be understood that the stated description of operation is given primarily to aid in giving 23b, and back to said tank. . ? If it is desired to stop the press when the re turn stroke is completed, the solenoid 28b is de energized and the centering device 21 moves the pistons of valves 23a, 23b to their mid-positions? to cut oil the discharge of the pumps 22a, 22!), from any hydraulic connection with the several a full understanding of the invention and that the present invention is not limited to apparatus which necessarily operates in the precise manner described. ' ram advance and return chambers in the manner One advantage of the invention resides in the use of electric controls wherein positive electric connections rather than brush connections may already explained. Immediately thereafter, the be employed inasmuch as the limited range of transfer of liquid by the pump 35 from the left to the right siderof the press operates to lower the ram l8?) relatively to ram I8a thus restoring the parallelism of the slide. rotation of the casing 68 makes it possible to utilize ?exible connections to the several incan descent lamps and cells or to the several men tioned limit switches. Another advantage is While this restoration is taking place there oc-v 15 found in the fact that there is no appreciable curs a reverse or counterclockwise rotation of the load imposed upon the racks 56, 51 and the sev disc 66, activating cell 48 to cause reverse oper eral related gear trains, so that no material lost ation of the motor 41 which, as a result, shifts motion or backlash is encountered which would the pump control member 37 toward non-pump delay the action of the disc 66. The latter, in ing adjustment. Meanwhile, the casing 68, again 20 consequence, yields immediate control over the actuated through the medium of the rack Tl, ro several photoelectric cells or limit switches and a tatescounterclockwisely in a follow-up motion resulting immediate initiation of the operation of relatively to the disc 66 which brings the two into the pump compensating means. Another of neutral relative positions, causing the motor 4'! many advantages derivable from well designed to stop and leaving the press slide in substantial apparatus according to the invention is the sub parallelism, in readiness for a following similar stantial elimination of any rocking motion during cycle of operation. 7 the pressing portion of the advance stroke of the If the press is so controlled as to start a further press, although the invention is of such breadth advance stroke, automatically, upon the termina as to include structures in which, for one reason tion of the return stroke, the mentioned restora 30, or another, such rocking may occur. tion of the parallelism of the slide would ordi In? any event it is clear that the concept dis narily occur in the manner just described, during closed herein may be practiced in numerous forms the initial or non-pressing part of the succeeding without departing from the invention as de?ned advance stroke. If under either- the mentioned in the accompanying claims. non-automatic or the automatic type of press op What I claim is: eration, the said restoration to parallelism is not 1. Apparatus for controlling the slide move effected before the pressing part of the advance ment in a long-bed hydraulic press having slide stroke begins, the unequal resistance to the ad actuating rams and related ram advance cham vance movement, in any event, sets in motion the compensating mechanism in the manner already 40 bers disposed toward opposite sides of the press slide and means for pumping liquid to said cham described. bers, the said apparatus comprising adjustable As the cells 48 and 49 become activated in re compensating means for effecting compensating sponse to the rotation of the disc 66 in opposite variations in the volumes of liquid pumped into directions and as the said cells yield opposite op eration of the motor 4'! and the casing. 68, it is -" said chambers, actuating means for varying the adjustment of said compensating means, and obvious that the described apparatus will yield control means having two coacting, separately compensation opposite to that herein described, movable portions for controlling said actuating where required by operating conditions. means; one of said movable portions being adapt The second embodiment The illustrated second embodiment, shown in Fig. 6, diifers from the ?rst embodiment only in that the disc 66a, instead of having the arcuate ed to move in response to variations in the atti tude of the press slide to initiate operation of said actuating means, and the other of said mov able portions being adapted to move in response to variations in the adjustment of said compen opening 15, has a raised arcuate cam surface 82 which may be of the same shape as said opening, 5.? sating means to limit the operation of said actu ating means. and that, instead of the two photoelectric cell assemblies, there are provided two limit switches 83, 84, which may be directly connected, respec tively, in the circuits of the relays 50a, 51a, con trolling the motor 41. Those familiar with the (ill art will understand that this embodiment will function similarly to the described ?rst embodil 2. Apparatus for controlling the slide move ment in a long-bed hydraulic press having slide actuating rams and related ram advance cham bers disposed toward opposite sides of the press slide and means for pumping liquid to said cham bers, the said apparatus comprising adjustable compensating pumping means for e?ecting com pensating variations. in the volumes of liquid The foregoing description sets forth preferred embodiments of this invention and a preferred cs pumped into said chambers, a reversible motor for varying the adjustment of said compensating mode of operation of the apparatus constituting means, and control means having two interacting, the invention. While the design of the compo separately movable members for controlling said nent parts of the apparatus should preferably motor, one of said members being adapted to yield the described mode of operation, neverthe less, it should be apparent that diii?erences in p. move inresponse to variations in the attitude of the press slide whereby to start said motor to in design of parts or differences?in conditions, as where complex and varying non-uniform resist itiate a variation in the adjustment of said com ances to the slide advance are e'ncountered, may pensating means, and the other of said members cause the invention to yield a somewhat different being adapted to move in response to variations ment. compensating operation than described. It , in the adjustment of said compensating means 2,405,640 13 whereby to stop said motor to terminate the var-v iation in such adjustment. 3. Apparatus for controlling the slide move ment in a long-bed hydraulic press having slide actuating rams and related ram advance cham 14 sating means, a make and break device for con trolling operation of said motor in opposite direc tions, and control means for said motor compris ing a ?rst member, movable in response to varia tions in the attitude of the press ?slide, and a sec bers disposed toward opposite sides of the press slide and means for pumping liquid to said cham ond member, movable in response to variations in the adjustment of said compensating means; the bers, the said apparatus comprising adjustable two said members being adapted, upon relative compensating pumping means for effecting com movement thereof, to operate said make and pensating variations in the volumes of liquid 10 break device whereby to modify the control ex pumped into said chambers, ?a reversible electric erted by said control means upon the electric motor for varying the adjustment of said com motor; the movement of said ?rst member being pensating means, and control means having two interacting, separately movable members for controlling oppositely acting electric circuits through said motor, a ?rst one of said members in one or the other of opposite directions depend ing upon the direction of variation in the attitude of the press slide and being adapted to initiate a compensation-yielding variation in the adjust ment of said compensating means; and the move ment of said second member being subsequent to being adapted to move, in response to variations in the attitude of the press slide, in either of op posite directions depending upon the direction and in the same direction as that of said ?rst of such a variation, whereby to start said 20 member and being adapted to terminate the motor to initiate a compensation-yielding varia variation of such adjustment. tion in the adjustment of said compensating 8. Apparatus according to claim '7, further means, and the other of said members being characterized in that the said make and break adaptedto move, subsequently to and in the same device comprises two photoelectric cells for con direction as the movement of the ?rst one of trolling operation of said motor in opposite di said members, in response to said adjustment rections, and one of the said movable members variation, whereby to stop said motor to ?termi has a shutter opening therein arranged to move, nate the variation in such adjustment. upon relative movement of said two members, 4. Apparatus for controlling the slide move between a non-registering ?position, preventing ment in a long-bed hydraulic press having slide so passage of light to either of said cells, and either actuating rams and related ram advance cham of two different registering positions, permitting bers disposed toward opposite sides of the press passage of light to one or the other of said cells. slide and means for pumping liquid to said cham 9. Apparatus according to claim 7, ,further bers, the said apparatus comprising adjustable characterized in that the said make and break compensating pumping means for effecting com 35 device is mounted upon and moves with one of pensating variations in the volumes of liquid the mentioned movable members. pumped into said chambers, a reversible electric 10. Apparatus according to claim '7, further motor for varying the adjustment of said com characterized ?in that the said control means pensating means, and control means comprising comprise a diiferential assembly coacting with two electric circuits, adapted to control opera 40 and deriving its operation from the movement of tion of said motor in opposite directions, a make opposite sides of the press slide, that the said and break device in each of said circuits, means, ?rst movable member is adapted to be rotated responsive to variations in the attitude of. the press slide, for starting said motor, through es tablishment of a circuit in One of said devices, to initiate a compensation-yielding variation in the adjustment of said compensating means, and means, responsive to the variation in such ad justment, for stopping said motor through break by said differential assembly, that the said sec ond movable member is adapted to be rotated by said electric motor. - 11. Apparatus according to claim 7, further characterized in that the said control means comprise a differential assembly coasting with and deriving its operation from the movement ing of said circuit in said device, to terminate the to of opposite sides of the press slide, a rack, co variation in such adjustment. acting with and driven by said motor, that the 5. Apparatus according to claim 4, further said ?rst movable member is adapted to be ro characterized in that the said make and break tated by said differential assembly and the said devices each comprises a photoelectric cell hav second movable member is adapted to be ro ing circuit-controlling characteristics which are tated by said rack. ' Variable in response to variations in the attitude 12. Apparatus according to claim '7, further of the press slide and in the adjustment of the characterized in that the said make and break said compensating means. device comprises an electric switch, and one of 6. Apparatus according to claim 4, further the said movable members has a cam surface characterized in that the said make and break CO thereon, arranged to operate said switch upon devices each comprises an electric switch adapt movement of said ?rst member and to discon ed to shift between its open and closed positions tinue the operation of the switch upon subsequent in response to variations in the attitude of the movement of the said second member. ' press slide and in the adjustment of the said com 13. Apparatus for controlling the slide move pensating means. , ment in a long-bed hydraulic press having slide 7. Apparatus for controlling the slide move actuating rams and related ram advance cham ment in a long-?bed hydraulic press having slide bers disposed toward opposite sides of the press actuating rams and related ram advance cham slide and means for pumping liquid to said cham bers disposed toward opposite sides of the press bers, the said apparatus comprising adjustable slide? and means vfor pumping liquid to said cham 70 compensating means for effecting compensating bers, the said apparatus comprising adjustable compensating means for eifecting compensating variations in the volumes of liquid pumped into said chambers, a reversible electric motor for op positely varying the adjustment of said compen , variations in- the volumes of liduid pumped into said chambers, means responsive to variations in the attitude of the press slide, for initiating variations in the adjustment of said compensat 75 ing means, and means, responsive to such varia 2,405,640 15 16? tions in adjustment, for terminating variations and a second member adapted to coact with said first member upon such movement to controlan in such adjustment. ' 14. Apparatus for controlling the slide move ment in a long-bed hydraulic press having slide actuating rams and related ram advance cham bers disposed toward opposite sides of the press slide? and means for pumping liquid to said chambers, the said apparatus comprising adjust able compensating means for effecting compen electric circuit, a motor controlled by said circuit and adapted when operated to start operation of said reciprocable adjustment member and to ac tuate said second member in a follow-up move ment relatively to said ?rst member whereby to restore the relative positions of said two mem bers and limit the operation of the motor and of ' ' sating variations in the volumes of liquid pumped 10 the adjustment member. 18. Apparatus for controlling the adjustment into said chambers, and control means compris in the rate of ?ow of a ?uid pump having a mov ing a ?rst control member, movable in response able ?ow-rate adjusting member, the said ap to variations in the attitude of the press slide, paratus comprising a motor for moving said ad for initiating a variation in the adjustment of justing member, a speed-reducing connection be said compensating means, and a second control tween the motor and the ?ow-rate adjusting mem member, adapted, in direct response to such vari ations in adjustment, to pursue? a? follow-up ber adapted to limit the latter member to rela tively slow movement, two coacting control mem ?movement relatively, to the movement of said bers for controlling said motor, means respon-i ?rst control member, for terminating the vari ation in the adjustment of said compensating 20 sive to movement of said control members rela tively to each other for starting and stopping said means. 15. Apparatus for controlling the slide move motor, a movement of a ?rst one of said con ment in a long-bed hydraulic press having slide trol members from an initial relationship rela tively to the second control member causing said actuating rams and related ram advance cham bers disposed toward opposite sides of the press 25 motor to start, and the second of said members having a continuously operable connection to slide and means for pumping liquid to said cham said adjusting member and being adapted, when bers, the said apparatus comprising adjustable the motor is operated, to derive a follow-up mo compensating means for e?ecting compensating variations in the volumes of liquid pumped into tion from the adjusting member, in the same di said chambers, actuating means for varying the 30 rection as the mentioned movement of said ?rst adjustment of said compensating means, and control member, whereby to bring the twocon control means comprising two photoelectric cells trol members into their mentioned initial rela tionship, to stop the motor.? adapted to control the operation of said actuat 19. Apparatus for controlling the rate of de ing means in opposite directions, the changes in the operating characteristics of the cells, to ef 35 livery of ?uid to a chamber of a ?uid-actuated fect such control, being derived from variations motor; comprising a pump adapted to'pump ?uid in the attitude of the press slide and from subse to the chamber. adjustable ?ow-varying means quent variations in the adjustment of said com adapted to vary the rate of delivery of ?uid from pensating means. said pump to said chamber, actuating means 16. Apparatus for controlling the slide move 40 adapted to actuate said flow-varying means, and control means for controlling the operation 'of ment in a long-bed hydraulic press having slide said actuating means; the said control means actuating rams and related ram advanced cham comprising two coacting members adapted to bers disposed toward opposite sides of the press control the operation of said actuating means slide and means for pumping liquid to said cham whereby to effect adjustment of the ?ow-varying bers, the said apparatus comprising adjustable compensating means for effecting compensating means to increase or decrease the ?ow of ?uid variations in the volumes of liquid pumped into to said chamber, the said two members being initially movable relatively to each other from said chambers, actuating means for varying the an initial relationship in response to movement adjustment of said compensating means, and control means comprising two electric switches of a driven member of said motor, different than adapted to control the operation of said actuat a predetermined movement thereof, to initiate operation of said actuating means to correct such ing means in opposite directions, the shifting of said switches between open and closed positions, movement, and subsequently movable relatively to effect such control being derived from vari toveach other, back to said initial relationship, ations in the attitude of the press slide and from in direct response to the mentioned operation of subsequent variations in the adjustment of said said actuating means, whereby to'terminate cor; compensating means. . . rection of such movement. 17. Apparatus for controlling the slide move 20. Apparatus for controlling the adjustment ment in a long-bed hydraulic press having slide in the rate of ?ow of a ?uid pump having a mov actuating rams and related ram advance cham able ?ow-rate adjusting member, the said ap bers disposed toward opposite sides of the press paratus comprising a motor, two coacting control , slide and means for pumping primary supplies of members for controlling said motor, means ?re liquid to said chambers, the said apparatus com sponsive to movement of said control members prising a compensator pump? for effecting com relatively to each other, for starting and stopping? pensating variations in the said volumes of pri said motor, a movement of a ?rst one of said mary liquid supplies, a reciprocable adjustment control members from an initial relationship rel member of said compensator pump, adapted to atively to the second control member causing said effect variations in the ?ow of liquid there motor to start, and the second of said members: through, a pair of racks disposed at opposite sides having a continuously operable connection to of the press, a pair of shafts coacting with and said adjusting member and being adapted, when turned to similar degrees by said racks in con the motor is operated, to derive a follow-up mo sequence of uniform advance movement of the tion from the adjusting member, in the same? press slide, a mechanism having a ?rst member direction as the mentioned movement of said adapted to move in response to any difference in ?rst control member, whereby to bringlthe two the degrees of rotation of the said pair of shafts control members into their mentioned initial re 2,405,640 17 18 - lationship, to stop the motor, the said apparatus being further characterized in that the said ad justing member is reciprocable and adapted to predetermined relationship in movements of two means. eration or deceleration of either of the two ele ments to restore the latters? predetermined rela elements, comprising separate driving motors for driving each element, a compensating motor reversibly vary the flow of ?uid through the adapted to modify the relative movements of said pump; in that the said motor is reversible; and? elements to compensate for departure from said in that the said two control members are mov predetermined relationship, a movable control able in opposite directions whereby to control device adapted to control the operation of the the starting and stopping of the motor in the re compensating motor, an adjustment motor adapt verse operations thereof, ed to operate said control device, and compen 21. Apparatus for substantially maintaining a 10 sation control means for controlling the opera predetermined relationship in movements of two tion of said adjustment motor; the said compen elements, comprising separate driving means for sation control means comprising two coacting each element, compensating means adapted to members, a ?rst of the latter members being mov modify the movements of said elements, a mov able from an initial relationship relatively to the able adjustment member for said compensating other member, in response to departure of the means for adjusting the modifying e?ect of the two elements from their predetermined relation latter upon the movements of the two elements, ship of movement, to start the adjustment motor actuating means for actuating said adjustment and thereby adjust the compensating motor to re member, and control means for controlling the store the said predetermined relationship, and a operation of said actuating means; the said con second of said two coasting members having a trol means comprising two coacting members in continuously operable connection to said adjust itially movable relatively to each other from an ment motor adapting it to pursue a follow-up initial relationship, in response to departure of motion in the same direction as the mentioned the two elements from their predetermined re movement of the ?rst member, whereby to bring lationship of movement, to initiate operation of i the two said members into their mentioned initial said actuating means of a character adapted to relationship, to stop the adjustment motor. restore the said predetermined relationship, and 24. Apparatus according to claim 23, further subsequently movable relatively to each other, characterized in that the compensating motor, back to said initial relationship, in response to the adjustment motor and the two mentioned the mentioned operation of said actuating means, 30 members of?the compensation control means are to terminate such operation of the actuating reversible in operation whereby to provide accel 22. Apparatus according to claim 21, further characterized in that a ?rst of said coacting mem tionship. ' bers is operatively connected to both the driven 25. Apparatus according to claim 23, further elements and adapted to move in response to movements of the latter other than in the men tioned predetermined relationship and a second of said members has a continuously operable con characterized in that the compensation control means include electric apparatus, responsive to movement of the mentioned two members from an initial relationship to start the adjustment motor and to movement of the two members back nection to the mentioned actuating means adapt ing the second member to pursue a follow-up movement in the same direction as the ?rst member. _ 23. Apparatus for substantially maintaining a to initial relationship to stop the adjustment motor. ? EARL CANNON.