Octe 1, 1946. |_. A. ISPIEVAK ADJUSTABLE HOLD-DOWN DEVICE Filed March 29, 1943 ' 2,408,586 2,408,586 Patented Oct. 1, 1946 Louis A. vSpievalr, WestLos AngelesjGalifeg l’ V ' Application March 29, 1943, SerialNo. 480313 ' 1 Claim; .v . 1 ' (01.,144i290) . v My invention relates to hold-down devicesand which the ‘adjustment ‘may be readily made to ' " dispose a clamping bar in a‘ desired position and has‘particular reference tea-device to be secured thereafter the foperation of ‘the clampingibar to clamping position willalwa'ys dispose the clamp ‘upon or attached to a work table to engage and hold workpieces down upon the table in a desired ing bar in the adjusted position. position to permit the performance of manufac ' ' Another’ object? of fmy'i invention is ‘to provide turing operations upon such workpieces. "a. hold-down'deviceo'f the character ‘described wherein the adjustment may be'altered “from time time or_'th_e clamp may be ‘adjusted initially ufacture (large quantities’ of identical parts by to‘ ‘building jigs to be associated with variousymaé 10 to a 'desired'lpo'sition' and the adjustment is'then permanently ?xed.’ ‘ h “ p I “ ‘ chines’which are to perform manufacturing oper ' Other objects’andadvantageslof my invention ations upon these parts to locate the parts on the will be apparent from a'study of the following machine in a. desired position for the perform speci?cation, read in connection with the ‘accom ance of such manufacturing operations. "The I In industries such asfautomobileand aircraft manufacturing it is the common practice to man problem which is presented is to'hold the various 15 workpieces in position in the jigs or upon desig- I e _ Fig. 1 is a perspective viewof an adjustable hold-down device constructedin ‘accordance with nated portions of a work table of the machine, with assurance that the workpiece will not be panying drawing, wherein? - my invention; Fig. 2 is aside élevational View, partlyin sec} readily displaced ‘from thedesired position dur ing the performance of the work. For this pur 20 tion, of thezfhold-downidevice shownin'Fig. I}; Fig. 3' an end elevationalwview of the ‘hold pose various types of hold-down devices or quick down device illustrated in Figs. 1 and 2; acting clamps have been devised,’ a typical exam; v‘ Fig. 4 is?a side "elevationallview of the hold‘ ple being that shown in my cope‘ndingv applica down deviceillustrated in Figs. l through 3, and tion Serial No. 405,964, ?led August 8, 1941. The illustrating the position‘ of the clampingbar and common characteristic of these hold-down de- . 25 : handle whengvthevclamping bar is in its'released vices is the use of a bar or workpiece engaging or non-working position; member which is held in a clamped position on ‘ _ _v v _v v I Fig. 5 is a sideelevational View of a modi?ed the workpiece by means of cams or toggle joints by which a handle may readily move the clamp ing bars into and out of engagement with the ‘ workpiece and to hold the clamping’ bars inth'eir type of adjustable hold-down device embodying mylinventionjand Fig. 6.is a front view,‘par_t_ly_in ,_ " section, _ > w of the hold-down device illustrated in ,Fig. '5. ., clamping positions without .the ‘necessity of ‘em ' I, Referring to the drawing, I have illustrated . Fig.1 a typical hold-down devicevconstructedrin I Heretofore the clamps or hold-down devices .35 accordance with my.’ invention as comprising a pair of. supp'ort'members I and 2 which maybe have been speci?cally designed to disposethl constructed ‘as angular brackets: having, verti clamping bar a predetermined distance away from cally extending portions 3 and 4, respectively, the work table whenever it is in its clamped posi and horizontally extending foot portions 5 and 6, tion; requiring either the use .of spacing blocks ploying additional looking or holding mecha nisms. ' j , , , _ respectively. The foot portions 5 and .6 are adapted to be secured to the surface of a work I between the workpiece and the table or between the clamping bar and, the workpiece if the thick ness'of the workpiece ‘does not coincide with the predetermined distance between the clamping table or tothe' work supporting surface of a machine which is to be usedto perform a manu facturing operationupon a workpiece. The se bar and the work table for which a clamp or 45 curing of the feet 5 and'? may be accomplished holdedown device has-been speci?cally designed. Iv _ _It is therefore an object of my invention to “ ‘ in any desired manner ‘such as by welding the " provide va hold-down of the type described, in which thedistance between the clamping bar and the work table when the clamping bar is in working or clamping position may be'readily feet directly to the work table or work supporting surfaces. . ' ‘ ' ' each other a suii‘icient distance to permit 50 from the interposition therebetwee'n of a clamping bar adjusted to adapt the hold-down device to work;- ~ - pieces of anin?nite numberof differentcthick 7 ‘The supports "I and '2 are spaced horizontally ‘I pivoted to the supports ‘I and 2 by means of a pivot pin 8 so‘ as to permit ‘the clamping bar to be moved fromv its horizontally extending posi Another object of my invention is to. provide tion, as shown in Fig. 1, to asub'stantially verti 55 a hold-down device of the class described,’in nesses. ' . ' .. 2,408,586 3 4 cally extending position, as shown in Fig. 4. The clamping bar 1 constitutes a lever fulcrumed at its pivot pin 8, the opposite end 9 of the bar ‘I would be possible with the clamping bar in its cated at !3 to the handle Ill and also pivoted upon a bolt l4 adapted to extend through match Once the bolt l4 has been shifted su?iciently to make the working position of the clamping ing slots 15 in the supports l and 2. The form of handle shown in Figs. 1 through 4 is generally that of a bellcrank, the longer lever of the bellcrank constituting the direct handle portion to be engaged and manipulated by the 15 bar 1 adapted for a particular thickness of work piece, the nut l6 may be tightened with assurance that upon each operation of the handle 10 the clamping bar will move to the new working posi horizontal position. Likewise shifting the bolt forwardly in the slot IE will dispose the working being connected to a handle In as by means of a position of the outer end of the clamping bar at pivot pin or rivet l l by which the handle and bar Oi a, greater distance away from the work table, such may rotate relative to each other. as isshown in the dash line position indicated The handle Ill is supported upon the supports at [8 in Fig. 2', thus accommodating the clamp to l and 2 as by means of a link l2 pivoted as indi workpieces of greater thickness. hand of an operator while the short leg of the - tion. In Figs. 5 .and 6 I have illustrated a modi?ed form .of clamp embodying my invention as com bellcrank extends substantially at right angles to the handle portion so that when the clamping bar prising‘ a pair of supports 2| and 22 which, like 1 is in its clamping or working position, as shown the supports l and 2, may be provided with hori in Fig. 1, a line extending through the axes of 20 zontally extending feet 23 adapting the supports the pivot pins or rivets I I and I3 and the bolt to be secured to a work table or working surface. l4'will be a straight line, the short leg of the In this form of hold-down device the clamping bellcrank and the link l2 constituting in effect bar 24 is pivotally mounted as by a pivot pin or a toggle. rivet 25 to the vertically extending portions of To facilitate manufacture and assembly of the 25 the supports 2| and 22 to swing from a clamping type of hold-down device illustrated in Figs. 1 or working position, as shown in full lines in through 4, the short leg of the bellcrank consti Fig. 5, to a released or non-working position, as tuting the handle l0 may be slotted or bifurcated, shown in dotted lines in Fig. 5. as shown in Figs; 1 and 2, so that the link I2 may , r ' The clamping bar 24 is moved between these be made of a thickness considerably less than the 30 positions by means of a handle 26 having its thickness of the handle member ID and may be lower end slotted as indicated at 21 to straddle interposed in the slot formed'by bifurcating the the rearward portion of the clamping bar 24 to which it is pivoted by means of a pivot pin or With the clamp structure as'thus far described, rivet 28. The handle 26 is coupled to the sup it will be apparent that moving the handle to a ports 2| and 22 by means of a pair of links 29 substantially horizontal position, as is shown in and 39 which may extend one on each side of the Fig. 1, will cause the clamping bar to rotate about handle 26 to which the links are pivotally con its pivot pin 8 until the clamping bar is disposed nected by means of a pivot pin or rivet 3|. The in a substantially horizontal position as shown in I lower ‘end of the links 29 and 30 engage crank Fig. 1 and in this position the toggleformed by 40 pins 32 and 33 formed upon opposite ends of the handle and link will be “straightened out” a pin or section of rod 34, the crank pins being and will act to lock the clamping bar ‘I in its disposed eccentrically with respect to the axis clamping or working position. In this position of the pin 34. The pin 34 is rotatably mounted the handle is substantially horizontal and lies in circular openings in the supports 2] and 22 below the upper limits of the support members I 45 so that the pin 34 may be rotated relative to and 2, thus being out of any possible obstructing the supports. . ‘position. Likewise ‘movement of the handle in _With the construction thus far described, from the position shown in Fig. 1 to the position movement of the handle 26 in a counterclock shown in Fig. 4 will swing the clamping bar 1 ; . wise direction will swing the clamping bar 24 to about its pivot 8 until the bar is disposed in, a 50 its working position, as illustrated in full lines substantially vertical position, as shown in Fig. 4, in Fig. 5, at which time the pivots 3|, 28 and and in this position both the handle and the 33 will be disposed in a straight line, the com clamping bar are disposed in positions which will bination constituting a toggle joint in which the not obscure the surface of the work table and will toggle is "straightened out.” Movement of the leave the work table accessible to the workman _andle 26 in a clockwise direction will ?rst for the placing of a new workpiece or the removal ‘break” the toggle and then will cause the clamp of a ?nished piece, _ing bar 24 to be moved in a clockwise direction It will be observed that the slots IS in the sup to its released or non-working position, as shown ports I and 2 areformed on the arc of a circle in dotted lines in Fig. 5. and the shape of the slots is so disposed upon 60 The space between the outer end of the clamp the supports that one end of the slot is consider ing bar 24 and the‘ surface of the work table ably higher from the work table than is the other may be readily adjusted by rotating the pin 34 end of the slot. Thus if thelbolt I 4 is shifted in its openings 35 to move the crank pins 33 to from the position shown in Figs. 1, 2 and 4, and a position closer to or further away from the . is disposed in some other position within the slot, 65 work table surface. Any movement of the crank the working position of the clamping bar ‘I will pins 33 further toward the Work table surface not be horizontal but will form a greater or lesser will cause the'working position assumed by the angle relative to the work table surface. Thus clamping bar 24 to be with its outer end closer by loosening the nut IS on the bolt and shifting to the work table surface, such as is indicated in the bolt rearwardly of the slot 15, the working 70 dash lines 36 in Fig. 5. It will be apparent therefore that the _pin 34 position of the outer end of the clamping bar ‘I may be rotated until the working position of the may be disposed closer to the work surface, as clamping bar 24 assumes any desired position shown in the dash line position at I‘! in Fig. 2, to adapted for the particular thickness of the work accommodate the hold-down device for engaging and holding a thinner or narrower workpiece than 75 piece with which it is to be associated. The pin handle. - ' » > 55 a 2,408,586 may then be ?xed against inadvertent move ment to some other position as by means of welding the ends of the pin 34 to the supports 2| and 22. It will therefore be observed that I have pro vided a clamp or hold-down device which may a support member adapted to rest upon the _ working surface, a clamping bar; means pivoting said clamping bar upon said support member [for movement between a Working position dis posing the end of the bar a predetermined dis tance above the working surface to engage and clamp a workpiece against the working surface be readily adjusted to ?t a particular thickness and a non-working position disposing the end of workpiece and once 50 adjusted the adjust of said bar at a greater distance from said sur ment may be maintained either temporarily, as face; a handle member for moving said bar by the bolt and nut construction shown in Figs. 10 between said two positions; means pivotally in 1 through 4, or the adjusted position may be per terconnecting said handle with said bar; and manently ?xed, as indicated in Figs. 5 and 6. means pivotally connecting said handle to said In either case the manufacture of clamps or hold_ support including a pivot member engageable down devices is facilitated, a single design of with said support, a slot in said support for re which may be manufactured in large quantities 15 ceiving ‘said pivot member, saidslot extending at and then ?tted to di?erent distances between an acute angle relative to the working surface the work table and the clamping bar by merely whereby positioning of said pivot member at ?xing the position of the adjusting device. different positions along said slot will ?x the While I have shown and described the preferred working position of the end of said bar at dif embodiment of my invention, I do not desire 20 ferent predetermined'distances above said work to be limited to any of the details of construc ing surface to thereby accommodate workpieces tion shown and described herein, except as de of different thicknesses, and means for locking said pivot means in any position along said slot. ?ned in the appended claim. I claim: In a hold-down device for securing a work piece to a working surface, the combination of: 25' LOUIS A. SPIEVAK.