Jan. 1_4, 1947. ' J. R. NALBACH 2,414,164 CONVEYER Filed March 3,- 1945 3 Sheets-Sheet 2 Jan. 14, 1947. J. R. NALBAcH CONVEYER Filed March 3, 1945 y 2,414,164 3 Sheets-Sheet 3 Patented Jan. 14, 1947 2,414,164 ` UNITED STATES PATENT OF FIC E'y ' 2,414,164» CONVEYER» `l'olm R. Nalbach, Oak Park, Ill.,-- assignoi'ï‘ toA Middleby-Marshali @ven Company, Chicago, Ill.,` a corporation of Illinois Application March 3, 1945,' Serial No.' 580,763 7'Claims. ' l .The invention relates to improvements in con veyers. One object of the invention is to provide an (c1. 19a-153) 2 like manner whether the conveyor movesinV one direction or the other. An additional object of the invention is to endless" conveyer mechanism provided with kim provide rotary means for transferring the swing proved mean’s for stabilizing trays carried by the able ends of pivoted trays of a conveyer‘in conveyor as thev trays move arcuately about’end synchronism with the movement of the pivotal sprockets of the' mechanism~ The mechanism ' axes of the` respective trays as the axe-s' move herein shown and described is adapted for use arcuately about conveyor» sprockets andïmeans in' bake ovensV of the so-called traveling type but »cooperating with the rotary transfer mea-ns? af the invention is not limited to such use. l()v fording positive engagement with the swingable In traveling ovens a> pair of endless chains-hav tray ends whereby lengthwiseshiftirig oi’r other ing horizontal runs and passing at the ends irregularity of movement of the trays is-preven'ted around sprockets generally are employed `for mov during the transfer thereof from one horizontal ing trays within a baking` chamber, which trays run of the conveyer to the otheri» ‘ carry pans of` products to be baked. The trays 15 s. further object of the invention is to provide generally are attached pivotally to the chains a wholly cam-controlled. tray-gripping mech and-in stabilized tray ovens the` trays are re anism for swingable ends of` pivotedtrays for strained from tilting- during their passage within effecting positive. supporti of said tray ends by the baking chamber since tilting of the trays and tray transfer means during those` quadrants- of the pans .of dough or` batter carried thereby pro 20Y movement of the `latter during which axial shift duces final products that may be unshapely or ing of the trays is- most likely to occur. non-uniform and hence less desirable com Another object of the invention is to provide mercially. l , . ` , In effecting' the stabilization of such pi'votally supported trays-»stabilizingmechanisms of vari ous forms have been designed» and» some of which havebeen used commercially butnot infrequently smoothly acting tray transfer mechanism adaptedl for vuse under temperature' conditions, as in bake ovens, that renders the use’of con ventional lubricants as Well as springs non feasible. such mechanisms `have comprised arcuate guid ingtrack at the ends of the conveyors which, Other objects of the» invention relate to various features of construction Vand arrangement of in conjunction Vvwith other apparatus, have been 30 parts `that will be apparent from’a‘consider'ation calculated to retain the trays in horizontalrela of the following specification and accompanying tion as the same move arcuately in succession drawings, wherein: from one horizontal run. of the‘conveyer to the Fig. 1 is a broken vertical longitudinal sec tional view of a bake oven‘comprising conveyor mechanism that-is illustrative of the presentim other. However, the-movement oftray rollers along suchlarcuate tracks frequently is accom panied by irregularity in tray action, due pos sibly to imperfection or wear‘or misalignment of parts, andfwhichedoubtless is augmented by the changes in dimensions-of the‘several parts due tothe various temperature ranges `under which commercial bake ovens necessarily are operated to bakingJ various products. l It is animportantobject vof the present inven tion to provide mechanismuwhich. instead of mov ing tiltable: ends of trays‘a‘long curved tracks for stabilization purposes,` Aa‘ctually‘carries or trans ports such trayend’s durin'gïr the arcuate move ments thereof'îandï-thereby avoids the chattering ` and; otherirre'gulari‘tiesfin tray action above'men- l correa. y ‘ , A morefspec’iñ’c objec-t’ofithe invention‘is‘ to 'provide‘tray stabilizing means that'may be em ployed with» \ equal facility at the ’ :forwardV and rearff ends " of- a ~- conveyorl and thatI functions in" provements. l Fig. 2 is a broken top plan View illustrating-the conveyor mechanism and certainï baking cham ber framing members‘that support the conveyer mechanism, the insulation of the walls and other . features ofthe bake> oven not essential to the present improvements» -being omitted. Fig. 3 isran enlarged broken vertical sectional view takenon line r343- of Fig.` 2. l Fig. 4 is a sectional View takenon lined-‘4 of Fig. 3l but with the transfer arm assumed `to be in upright position._ » V Fig. 5 is an enlargedbroken vertical sectional View taken on line 5~5fof Fig. l2. Y Figs. '6, 7 and 8, are broken views-,of the cam controlled apparatusshown in-Fig. `4 and illus trates progressive positions of the mechanism ` during operation thereof. ` 5, Fig. 9 isa vertical sectionalview'taken online l 9-9 of Fig. 5. . 2,414,164 ‘ 4 In Fig. 1 a bake oven of the so-called traveling type is illustrated and generally, comprises a heat insulating inclosure Il] defining a baking charn ber II. The inclosure lo comprises walls sup ported by suitable framing in the form of struc tural steel members, indicated generally in Fig, 2 by the numeral I2. ' Disposed, within the chamber II is a pair of endless chains' I3 each having upper and lower horizontal runs and passing over sprockets I4 and I5 at the front and rear respectively of the conveyer. Y The fro-nt sprockets It, one at each side of the oven, may be mounted on a transverse shaft but, preferably, for the purpose of providing adequate vertical clearance between trays, the sprockets are mounted on stub shafts I6 each journalled in suitable bearings l'I supported by the frame I2. The sprocket l5, at the rear of the oven, are carried on stub shafts I8 which are journalled in Vbear-ings I9 carried by horizontally slidable structures each indicated by the numeral 20 and which Vare supported by the framing members. The slidable structures 2@ comprise springs 2l respective tracks for engagement by transfer mechanism hereinafter described. As a tray 2i, such as the tray identified as Zia in Fig. 3 approaches the sprockets Iâ at the rear end of the conveyer, the rear pivotal mem bers 23 there-of will be carried arcuately about the sprockets to the upper run of the conveyer, assuming `that the sprockets are moving in a clock-wise direction. For the purposeof main taining the trays 2l in horizontal relation as the ' rear pivotal ends are moved about the sprockets V I6, rotary transfer means are provided which en gage the forward ends of the trays and move .them arcuately concurrently with the movement of the rear ends, and release such forward ends _ for horizontal rolling movement upon the respec tive upper tracks upon completion of such arcu ate movement. The transfer means shown comprises rotary transfer arms 32 which are carried by stub shafts 33. Shafts 33are suitably journalled in bearings carried by the respective sliding structure 20 and hence the spaced relation of the shafts 33 with respect to the sprocket shafts i8 is maintained during shifting of the latter due to expansion which urge» the structures 2B to the right, as 25 or contraction of the chains. The spacing of the viewed in Figs. l- and 2 for moving the shafts i8 shafts 33 from‘the shafts' i8 is such thatthe and'sprockets i5 to the right and thereby keep transfer arms 32 will cooperate with the sprockets ingjthefphains I3, taut during expansion of the in retaining the trays in horizontal relation dur chains and permitting sliding movement of the 30 ing the arcuate movement of the trays. The sprockets l5 and shafts I8 in the opposite direc arms 32 areshaped at the ends .to provide receiv tion during contraction of the chains in response ing means for rollers 39 and as shown arecpro tdyarioustemperature conditions affect-ing the vided with ñngers or extensions 3d. The shafts same.- VThe sliding structure is more fully shown 33 are shown in Fig. 2 as being driven in syn in my Patent No. 2,369,840, granted February 20, 35 chronism with the shafts I8 by chains 35, " » . 1945. A As the tray, identified as 21a in Fig. 3 nieves-to VSecured to'the inner verticalside walls of the left from the position therein Shown to the the baking chamber, as to _the framing l2, are position of the tray identified asZ'Ib, it will be upper and lower horizontal tracks 22 and 23 at seen that the lower fingered of arm 32 will have eachsideof the oven. rI‘he tracks are shown as 40 been movedinto contact with the roller 30 of the formed of angle‘shaped steel members upon which the upper and lower horizontal runs of the chains aresupported and along which they, in effect, roll by Vreason of the conventional rollers 24 provided tray. It will be understood that a transfer mech anism is provided at each _side of the rear por tion of the oven and that they operate in syn chronism and hence but _one only will be de on the link pins 24a of the chains. The conveyer, scribed. However, any lifting action exerted by comprising the. two chains I3 and other asso the finger on the roller 38 of the tray 2lb will ciated load handling mechanism, is driven by any not be eifective in retaining Vthe tray horizontal, approved means, as by a motor 25 shown on the if in fact the ringer Will produce any initial ele top_of the oven. The motor by means of a chain vation of the forward end of the trai7 when the 25, drives the shaft I6 (if a single transverse shaft 50 latter is in the position of tray 2lb. It has been only isemployed) or by two such chains 26 in the common practice heretofore to vprovide auxiliary event .two stub shafts I6 are provided, as pre means for »cooperating lwith the- transfer arms Íerred. The conveyer may be driven in either at this point, such as Vcurved arcuate tracks along direction '.preferably, as by utilization oí a re which the rollers 39 are forced by the fingersV 34 versible -motor'or by suitable reversing mechanism 55 and other associated mechanisms. Such curvedV tracks and'associated mechanisms are dispensed (not shown) in the driving means. Y with by the present improvements since in many VA plurality of trays 21 are shown which are instances the arcuate movements imparted to the movable by the chains I3 and‘upon Which'pans trays were irregular, or jerky, whereas operation of bakery products to be Abaked may be placed forA movement 'within theY baking chamber. The 60 free of vibration'is desirable not only from the standpoint of durability but from the standpoint of uniformity in finished products; Hence, in stead of a rolling transfer movement at the`for-‘ the members 128 constituting extended link pins ward 'end lof the trays, Said‘ends are- .actually by means of which the trays are attached to the chains. 'Such pins 2B are located at or adjacent 65 transported bodily >from one run to the other similarly tothe rear ends. The improved means theA rear of» the trays- and hence the trays are for effecting the engagement of the forward tray swingable Y about the respective pins 28. The ' ends and effecting> the transfer from one run of forward endsl of the side walls of the trays are traysy ì'lare shownL secured to rear pivotal mem bers 28T at opposite lateral edges of the trays, provided with laterally extended pins 29 which carry rollers 3o kwhich are designed to engage 70 the inner» marginal portions of the respective tr'acksfor supporting the trays in horizontal re lation âS the trays move with the chains during theghorizontal runs of the latter. The rollers 3B l extend >inwardly of the inner margins of the 75 the conveyor to the other will now be described. As shown in Fig. 3, the transfer arm‘ 32 therein illustrated (the rear arm on the opposite `side of the oven being similar>wis provided with two similar hooks or cradling members 36, 31, each~ pivotally attached to the arm at’38, 39 respective-_ ly. ,The hooks A3,6, 31 aresymmetricallyarrangecl 2,414,164 U . with respECt to the respective nngers 3ft at the ends of the arms and both hooks will assume a given relation with respect to the associated fin d hooks 36; .31, which as stated are `pivotallv at tached to the arm 32 at 38, 39 respectively com prises a link ¿lil for each rear stabilizing mech ger 3ft in any given position of rotation of that finger.' Hence, viewing Fig. 3, as a tray 27 on the lower run ofthe chain moves to the left from a anism‘, which links are generally ring shaped with openings ¿Bw of suilicient diameter to re ceive the respective shafts 33 and the hubs 32a position not therein shown", to the position where in-the forward roller 3@ is directly beneath the of the arms 32 and permit movement of the links relative to said hubs.` To a link fit, a coopera shaft 33, the hook 35 will be in the lowermost dotted line position shown in said figure, that 10 tive pair of hooks 36, 3l is pivotally attached -by pins lil, 42, respectively. The pins lll, ¿i2 extend it will- be in engagement with the roller. As the from the hooks 36, 31 through the adjacent por tray- 21 moves to the position of tray identiiied tions of the links ed and are provided at the asilo; the hook Sii being in engagement with ends with rollers llt, fili which roll upon the ex the roller 3G will actually lift the forward roller from the lower track to the same extent and at 15 ternal peripheral surfaces of a disc shaped plate cam d5 that is non-rotatably supported by means the same rate of elevation as the axial pin 28 is of brackets 46 to the slidable structure 2l@ where being’arcuately elevated in moving about the by the parts described maintain c-ooperative re sprocket i5. The effective radius of arm 32 is lation with respect to the shaft I8 during expan the same as the effective radius of the sprocket sion and contraction of the chains i3. and hence theY tray is maintained in a horizon The cam 45 is provided with an aperture 45a tal relation as it is moved arcuately upwardly as described. When the arm 32 has reached the in .through which the associated shaft 33 extends, the cam, as stated being non-rotatable. termediate horizontal position shown in d-otted lines, the tray will be in the position identified by tray 27o and during the arcuate movement of the tray from the lower track through the lower left quadrant to the position of tray 2`lc, axis of rotation of shaft 33 as the cam center, are approximately equal but various portions of the surface of the cam periphery along which rollers d3, Il@ travel are of different configura the forward roller Sii will have been retained or tion whereby the hooks 3d and 3l are constrained to move into the operative position of hook 3S of Fig. 3 whenever either hook tâ or 3l is dis posed in the lower left quadrant of rotation shown in Fig. .3. The rollers d3, dit being'con nected to the link ¿lil by pins lill and ¿i2 and the cradled within the hook member 3S. During the movement of the finger 3ft, through the next quadrant, that is, from the intermediate hori zontal left hand position of Fig. 3 to the vertical position, the finger adequately supports the roller 30 andthe hook progressively backs away from the roller during such movement of the finger. In" substantiallythe upper vertical position of the arm 32 the tray will occupy the position des ignated 2lb, the roller Si) will move from the end of arm 32 into rolling contact with the upper track 22, the roller having been released‘from engagement yby the hook due to the withdrawal or retarded movement of the latter just described and illustrated in dotted lines in Fig. 3. Substantially concurrently with the horizontal rolling movement of roller Si) upon the track 22, the rear end of the tray, as represented by the pivot pin 23, also moves into the track 22 for sta The various diameters of the cam, considering the latter being carried by the hooks, constrain the latter to move pivotally about their axis pins 38, E9- into the operative lower left quadrant posi tion of Fig. 3 and- into inoperative positions dur- ` ing the remaining positions of the cycle. In Figs. 5 to 9 inclusive, which disclose cam P operated hooks for the forward portion of the oven, the functioning of the hooks is more clearly shown,` the novel transfer structures at the front being identical in principle to the transfer means . at the rear of the oven. ‘ `Referring to Figs. 5 to 8 inclusive there is therein` shown one of the two transfer means as sociated with the front sprockets lli for retain blized movement by the track throughout the ingA the trays in stabilized relation as the piv upper run of the’conveyer. During the move otally mounted rear ends of the trays move in ment of the ñnger 3a from the upper vertical 50 ysuccession _about the sprockets it in moving position to the lower vertical position the asso from one horizontal run of the conveyor to the i ciated hook 'i6 likewise performs no function other. ` ' since within that portion of the cycle the finger In Fig. 5 a tray El, indicated as Ele for iden carries no load but the other hook and finger tiñcation of position, is shown with its forward however will be elevating the forward end of the tray roller es in position to move oif the end of succeeding tray as described above. the upper track 22, it being assumed that the ’ The spacing of the trays and the relation of forward Sprocket id is rotating in a clockwise the parts participating in the transfer of the direction. A forward transfer arm ¿il is shown trays as described are such that the hooks 35 and 3,? alternately engage forward tray rollers 60 in vertical position with a finger ¿lâ in a substan tial contacting position with the roller. A sim for cradling the rollers during movement of the ilar linger de is provided at the opposite end of associated finger from lower vertical to horizon the arm. >¿is the sprocket ill continues its clock tal position and by a retarding action imparted wise movement, the rear end of the tray 21e will to the hooks during movement in the second begin to move arcuately about the sprocket while quadrant, the lingers only support the forward the :forward end of the tray will begin_a like rollers, Hence as each tray moves into position movement and the tray will be retained in hori where the rear pivotal axis thereof begins to move zontal relation by reason of the fact that the ef about'the rear sprockets l5, the forward end of the respective trays will be engaged by one pair or" the hooks 35, 3l and in cooperation‘with the respective fingers of the transfer arms will re tain the trays in horizontal relation during the movement from one horizontal run of the con fective radius of the arm ¿il is the same as that of the sprocket ill. The finger d8 will adequate ly support the roller 3i) during movement during the ñrst quadrant of 90° of arc from the verti cal position shown to a horizontal position and hence during such movement the hook Ell, simi p The means for controlling the operation ofthe 75 lar to those above described, is in a non-engaging or inoperative position. A similar hook 5i ispro veyer to the other. 2,414,164 retained in that relation by the effective cam dwells until the tray has moved into rolling con vided at the other end of the arm‘41. » The hooks 5o, 5I like those described above, are swingably secured to the. arm 41 by pivot members 52, 53, and. to the hooks a ring-like link 54 is pivotally secured at 55, 56 respectively. The pivotal pins 55, 55 as shown in Fig. 9, extend from the re spective hooks through the link and at their other ends carry rollers 51, 58 that are arranged tact with the lower track, that is, until the arm ' 32 is in the vertical position whereupon the hook 31, then in the lowermost dotted position of Fig. 3, will by reason of the then effective portion of the cam- surface, move counter `clockwise at a rate >to free the roller for rolling contact to the right along the lower-track 23. to follow the peripheral surface of a disc-like A In like manner the forward stabilizing mech cam 59 that is secured, as by a tubular bracket anisrn will be operated when the forward sprock 60, to a plate 6l that, in turn, is secured to the ets I4 rotate counter clockwise, as viewed in Figs. upper and lower tracks 22 and 23. The link 54 5 to 8 inclusive. In that instance Fig. 6 illus and the cam are, as those at the rear of the con trates the hook 5l approaching the roller as the veyer, ring-like to provide recesses that accom latter moves towardthe position of Fig. 5. In modate the hub of the arm 41 and the stub-shaft Fig. 5 the hook 5| is in engagement with the 62 of the arm which is appropriately journalled roller and will lift and cradle it during the next in the Vframing of the oven. The shafts 62, there 90° of arcuate movement to the position of Fig. being one on each side of the oven in association '7. From the latter position, by counter clock with the corresponding sprockets l4, are driven wise movement to the position of tray 21e, the in unison with the sprockets as by chains 63 20 hoc-k will be retarded, in eiîect, by clockwise from sprockets upon the respective front sprock movement on its pivotal axis since during such et shafts i6. ` movement the supporting end of the arm will Referring to Fig. 6, the arm 4'! is shown in a support the roller adequately. , position a few degrees of arc from the position -Since the upper portions of the arms 32 and 41 shown in Fig. 5 with the tray now identified as 25 extend above the level of the upper tracks and 2U lowered slightly from said position while in below the level of the lower tracks when the arms Fig. '7 the tray there identified as 27g is shown in intermediate relation. are in vertical position, out outs at the inner As the tray 27 was margins of the tracks are provided for such carried into the horizontal relation of Fig. '7, the movement as well as for accommodating the hook 50 was cam actuated into engaging posi 30 movement of the hooks below the level of the low tion with respect to the roller 30 since as the er tracks when the hooks are in the positions finger 48 approached the horizontal position its indicated in dotted lines in Fig. 3 and in Fig. v5. effectiveness as a support for the roller was re In Fig. 2 for example the rear or right hand end duced by change of relation. In Fig. '7 the hook cradles the roller 30 and prevents the tray from slipping forwardly, or to the right, and thus moving out of stabilized horizontal relation. of the upper tracks 22 are shown provided with The hook 55 was moved from the position of Fig. the upper track is provided to permit the rollers 3i) to be carried arcuately downwardly or up wardly (depending on the direction of rotation of the conveyer) as the rear ends of the trays cut'outs or notches 64 on the inner rear edges to provide clearance for the rotary transfer arms 32. 5 to the position 4of Fig. 7 by the cooperation of Vthe rollers 51, 58 and connecting link 54, the rollers having followed the cam surface in mov ing from their positions in Fig. ,5 to their posi tions in Fig. '7. During the movement of the tray from the horizontal position 21g, through posi tion 27h of Fig. 8 to the lowermost position of Fig. 5, the cam will, by reason of the configura tion of the dwells over which the rollers travel during such arcuate movement, retain the hook 55, as well as hook 5l, in the same relative posi tions with respect to the arm as are shown in Fig. '7. Hence the roller 30 is effectually cradled or supported by hook 5t and longitudinal shifting of the tray is prevented by the roller engaging A deeper notch 65 in each rear portionV of move arcuately immediately >>from or toward the level of the upper track under control of the rear sprockets It. To provide required clearance for thetransfer » mechanism adjacent the rear ends of the lower tracks 23, the latter are provided with cut outs or openingsßß through or into which the fingers of the rear transfer arms 32 and the associated hooks may pass as they move into engagement with forward rollers 35 as shown in dotted lines in Fig. 3. In Fig. 2 the openings 66 are shown bounded on the inner sides by inward track ex tensions G‘i that are welded to the inner edges of the tracks 22 to provide greater supporting hooks during the movement of the tray from the position of Fig. '7 to the lowermost position in dicated at 2li in Fig. 5. During the preceding 90° areas for the rollers 35 at the position of pick-ups arcuate movement, that is in the movement of by the hooks or release thereof, depending on the the tray from the position of Fig. 5 tothe posi direction of operation of the conveyer. tion of Fig. '7, the end of the arm' 47, including At the forward end of the upper tracks, cut 60 the associated ñnger 48 adequately cradled or outs or openings 68 therein are provided for ac supported the roller 3B to provide the desired sta commodating the upper portions of the forward bilization of the tray. chain sprockets i4. Such openings 68, in thefor It will be apparent that upon reverse move ward portions thereof extend to the inner edges ment of the conveyer resulting in the rotation of of the tracks to provide passage G9 to permit the the front and rear sprockets and front and rear 65 tray pivots 28 to move downwardly from the transfer arms in directions opposite from those tracks, or upwardly through the tracks, .as the above described, the same timed movement of trays begin or terminate respectively their -arcu the respective hooks will occur. For example in ate movements at the forward end of theV con Fig. 3, if the sprocket I5 be assumed to move veyer. Such passages 69 would of course permit counterclockwise, the upper end of the transfer 70 the forward rollers 3D of the trays to drop as arm 32 will receive and support the forward tray they move along the upper tracks at the forward roller 30 until it has been moved approximately ends of the upper tracks but to enable the rollers to the horizontal position identified as 21e when Sil to pass over the passages orV gaps 69 in the the»V hook 31>wil1 have moved, by cam action, in 75 upper tracks, supplementary rollers 10 are pro to cradling relation withthe roller and will be „9, 2,414,164 vided onrthe upper tracks which engage the `side edges Aof the trays before the rollers 3B arrive at the gaps and hence rprevent the forward `ends of :the `'trays from tilting downwardly by reason of the passage of the rollers 3d over >the gaps 5S. `'In the forward end portions of the lower tracks 10 into Vand from operative positions with respect to the ends of said arms within particular por tions of the paths of travel of said ends, a shiftable link'member pivotally secured to each of said hook members for swinging the same upon the respec tive pivots to and from said operative positions, 23, cut outs or passages 'H are provided for ac a fixed cam, and a pair of cam followers each commodating the ends of the transfer arms 41 associated with one of said hooks for following and the associated hooks Eil, e! as those portions move into and from the lowermost positions for 10 the surface of the `cam during rotation of said arm and each operatively connected to said link engagement with or disengagement from the for constraining said hooks to move in unison front rollers 3G, depending on the direction of ro into and from said operative positions sequen tation of the arms. ' tially during rotation of said arm. By reason of the action of the cam controlled 3. stabilizing apparatus comprising a rotary hooks which are carried by the transfer arms as 15 shaft, a transfer arm `mounted thereon and hav above described, the forward ends of >the trays are positively engaged by Y the hooks in those po ing opposed load supporting ends movable about said shaft, a pair of load engaging hook ‘members sitions within which the lingers of the transfer each pivotally secured adjacent an end. of said arms would be ineffective in lifting or supporting the 'tray ends or might not restrain longitudinal 20 arm and swing-able to and from an operative posi tion with respect to the respective arm ends, .a shifting movement of the trays to provide the de shiftable link member pivotally secured to each sired positiveness of support or security. The cam controlled mechanism including the de of said hooks for eñecting concurrent swinging scribed cooperating pairs of cam followers on each pair of hook members and the links con necting each pair of hook member, avoids the use of springs or spring actuated catches or latches within the heated chamber. The cam movement of said hooks upon shifting movement of the link member, a pair of opposed cam fol lowers each operatively secured to said link, and followers of each pair of followers being linked together are operated cooperatively by the respec a cam having a cam surface positioned for op erative contact by said followers for shifting said link in directions for swinging said hooks in uni son into respective operative positions sequentially during rotation of said arm. . tive cams to provide positive shifting of the re 4. Apparatus of the class described compris spective links and hence positive movement into ing a rotary shaft, a transfer arm mounted there and retention of the hooks within their respec on for rotation thereby and provided with load tive positions during each cycle of rotation of the carrying ends equally spaced from said shaft, a transfer arm. The transfer mechanism, as will be seen, actually transports the trays bodily 35 pair of hook members each pivotally secured to the arm adjacent an end thereof and swingable throughout their paths of arcuate movement into operative load supporting positions with re without use of cooperating stationary mecha spect to the respective arm ends, cam followers nism, such as curved tracks or the like, that by friction, vary the resistance to the movement 40 operatively connected to said hook members for effecting the swinging movement thereof, a cam of the trays through their arcuare paths and comprising a peripheral cam surface, and a link thus produce irregularities in the action of the trays. operatively attached to said followers for retain ing the same in contact with said cam surface The cam controlled gripping means for the during rotation of said arm for constraining said trays hereinabove described may be employed at hooks to move positively into and from the re both ends of the conveyer, as shown, or at either end. For example, the described mechanism can spective operative positions thereof. 5. Apparatus of the class described comprising a rotary shaft, a transfer arm mounted thereon for rotation thereby and provided with load carry may be desirable. While a structure illustrative of the improve ments has been shown and described, variations in the details thereof may be utilized within the spirit of the invention. I claim: 50 ing ends equally spaced from said shaft, a pair of hook members each pivotally secured to the arm adjacent an end thereof and swingable into operative load supporting positions with respect to the respective arm ends, cam followers oper 55 atively connected to said hook members for ef 1. stabilizing apparatus comprising a rotary fecting said swinging movement thereof, a cam, and a link operatively attached to said followers for constraining the same to follow the cam dur ing rotation of said arm whereby the followers 60 coact each with the other for preventing pivotal thereof, and means for retaining said tray por movement of either hook beyond the respective tions in the same relative positions with respect load supporting position under influence of the to said ends during the remaining portions of load thereon. said arcuate movements of the trays comprising o'. Apparatus for supporting in horizontal rela hook members pivotally secured to said arm and adapted to engage said tray portions during said 65 tion arcuately movable trays pivotally secured to transfer arm having ends upon which portions of arcuately movable trays are adapted to be sup ported during portions of the arcuate movement opposed portions of a pair of endless conveyor chains'arranged to pass over end sprockets at and means comprising a cam for actuating said the ends of the conveyor comprising a pair of hook members into and from said engaging po sitions in timed relation with respect to the move 70 rotary transfer members cooperatively positioned adjacent each pair of sprockets and having ends ment of the arm ends through the respective por for supporting opposed portions of the trays dur tions of said arcuate movements. ing portions of said arcuate movement thereof, a 2. stabilizing apparatus comprising a rotary pair of cradling members pivotally mounted on transfer arm, a pair of hook members pivotally secured to said arm and arranged to be swung 75 each of said transfer members for engaging said ODDOSed portions of the trays for supporting the remaining portions of said arcuate movements, 2,414,164 11 same during another portion of the arcuate move ment thereof, means linking the cradling mem bers of each pair together for movement in unison about the respective pivotal mountings thereof, a cam associated with each transfer member, and caml followers supported by each pair of said cradling members and revoluble by the latter about the respective cam in contact with the same whereby the cam eiîects movement of the re spective cradling members alternately7 into and from operative tray supporting positions. '7. Conveyer mechanism comprising a pair of spaced apart parallel endless chains having hori 12 Y trays for engaging portions of said tracks for cooperation with said pivotal members in support ing the traysupon said tracks as the trays move therealong, and rotary transfer means adjacent the sprockets at the ends of the chains for en gaging portionsV of successive trays at points spaced from the pivotal members thereof for re taining the trays in horizontal relation as said pivotal members -move about the respective sprockets, said rotary transfer means comprising rotary arms having receiving means for the en gaged portions of the trays, means for retaining saidrtray portions in said receiving means dur ing portions of the arcuate movement of the trays zontal runs, sprockets at the ends of the chains from one run of the conveyer to the other, and over which the same pass, tracks supporting the 15 cams for actuating said retaining means into and horizontal runs of said chains, a plurality of from operative positions with respect to the re trays disposed between the chains and each be spective receiving means. ‘ ing provided with pivotal members securing the trays to opposed portions of the chains, a pair of oppositely extended rollers carried by each of said 20 JOI-IN R. NALBACH.