US2431514A - Sheet feeding apparatus - Google Patents

Description

Nov. 25, 1947. 1 I c, s, s 'fz 2,431,514

SHEET FEEDING APPARATUS Filed Sept. 15, 1944 4 Sheets-Sheet 1 I I m I 7 3mm 7 g CLIFFORD s. SELTZER Nov. 25, 194-7. c, s SELTZER 2,431,514

' SHEET FEEDING APPARATUS Filed Sept. 15, 1944 4 Sheets-Sheet 3 won CLIFFORD S. SELTZER NW5 25%,, 1%4? g, g, SELTZER SHEET FEEDING APPARATUS Filed Sept. 15, 1944 4 Sheets-Sheet 4 R E 7.- T .L E s S D m F, W L C Patented Nov. 25, 1947 SHEET FEEDING APPARATUS Cliflord S. Seltzer, Warren, Ohio, assignor to The Taylor-Winfield Corporation, Warren, Ohio, a

corporation of Ohio Application September 15, 1944, Serial No. 554,326

This invention relates to the art of sheet feeding and more particularly to improved apparatus for automatically supplying individual sheets from a stack or stacks of the sheets to the automatically operated machines such as forming presses, tubular body makers, and 4 furnish such individual stock sheets or blanks in' a' more reliable manner than has heretofore been attained by devices employed afor comparable purposes.

Other objects of the invention are to provide automatic apparatus for the purposes stated which is more rugged and reliable in operation; to provide in such apparatus a greater flexibility of adjustments forj various sizes and thicknesses of the sheets tobe handled and to reduce the time required for changing over the apparatus to handle sheets of different size and thickness; to'materially reduce the tendency of apparatus of the subject nature to feed more than one sheet or blank at a time and to reduce to a minimum the time required for the essential movements of the timed elements whereby the productive output of the apparatus is materially increased; and to provide sheet feeding apparatus which i operative to maintain an uninterrupted flow of sheets to the receiving machine while the apparatus is being reloaded with bulk stacks of the sheets.

A more specific object of the invention is the provision of animproved automatic sheet feeding apparatus which is capable of receiving and handling very heavy bulk stacks of the sheets while nevertheless maintaining an uninterrupted and uniform flow of individual separated sheets to the receiving device withwhich the sheet feeding apparatus is associated. Thus, the employrnent of the principles of the present invention allows the construction and eflicient operation of wholly automatic and high speed sheet feeding machines in connection with heavy sheet stock or substantial size.

Another object of the invention is the provision of an. improved sheet separating apparatus of the stack top take-off type. J

Still further objects of the invention include the provision of an improved vacuum cup actuating assembly for separating individual sheets e'nt invention;

. 2 of an improved general assembly in sheet feeding apparatus of the kind which is operative to maintain an uninterrupted flow of individual sheets whereby a portion only of the operative elements of the complete assembly need be rendered readily inoperative to allow the replenishingand/or rearranging of the base or bulk stack of the sheets.

The above and other objects and advantages of the invention will become apparent upon consideration of the following detailed specification and the accompanying drawing wherein there is disclosed a preferred embodiment of the invention.

In the drawing:

Figure 1 is a front elevation of a machine constructed according to the principles of the pres- Figure 2 is an end elevation, partly in section, of the apparatus of Figure 1;

Figure 3 is a plan view of the apparatus of Figure 1;

' Figure 4 is a vertical section along the lines IV-IV of. Figure 3;

Figure 5 is a fragmentary sectional view taken along the line V-V of Figure 2;

Figure 6 is a fragmentary sectional view taken I I along the line VI-VI of Figure 1; and

Figure 7 is a longitudinal sectional view of one of the vacuum cup actuating devices utilized in the assembly of Figure 1.

In the drawing, reference numeral Ill designates a base which is U-shaped in plan and of the base I0 support a, housing I5 while a similar but reversed housing I6 is supported on the columns II and I2 which extend upwardly from the right leg of the base I 0. As will become apparent later, housings I5 and I6 support substantially all the operative elementsof the complete assembly and to lend strength and rigidity to this supporting structure a strut I1 rigidly interconnects the housings I5 and I6 at the forward end of the machine. suitable interconnections are made between the various columns and the base Ill as well as between the various colu'nns and the housings I5 and It to insure the maintenance ofthe vertical alignment and parallelism of the various columns.

Extending upwardly and forwardly of the rear portion of the base I 0 is a bulk stock rack ,con-

It should be understood that 'A similar housing 23 enclosing a.

sisting of a plurality of spaced brackets I8 held assembled by a bolt I9 and suitable spacing sleeves I9 as will be understood. Mounted on the rear center portion of the shelf provided by the brackets I8 is a block 20 on which is mounted a housing 2I (see Figures 1 and 4) which slideably encloses a finger 22 for movement toward and away from the center of the machine. similar slideable finger 24 is supported in depending relation by the strut II. Fingers 22 and 24 are urged inwardly by suitable spring means 22' and 24' and have wedge-like detents On their inner ends to support an auxiliary sheet stack 25. Fingers 22 and 24 are also each provided with a recess to receive a cam I22 each of which isarranged to be rotated by a lever-lever 26 rotating the cam in housing 2| and lever 21 rotating the cam in housing 23. For reasons to be described below these cams are provided to retract the fingers 22 and 24- thereby withdrawing the projecting portions of the detents thereof from the upward path of travel of the sheets to be added to the bottom of stack 25. Such sheet adding or replenishing means will be described following the description of the mechanism utilized to separate sheets from the top of the principal stack supported on the rack provided by the brackets I8.

Slideably mounted on the columns II and I2 is a housing 28 (Figures 2, and 6) which is provided with a horizontal inwardly directed guiding channel 29 in which is slidea-blymounted a bar 36 having a wedge-shaped inner end tapering to a knife edge to enter between adjacent sheets of astack to lift the sheet or sheets which lie above the knife edge. For a purpose to be hereinafter described sufficient clearance is allowed between the top of the bar 30 and the ceiling of the channel 29 to allow the bar 36 vertical movement to an extent slightly greater than the thickness of the sheets being handled. The extent of this clearance may be adjusted by longitudinally moving the wedge block 3i. Bar 30 and block 3I are each provided with a longitudinally extending slot through which extends a spline shaft 32 axially but rotatably secured to and depending downwardly from the housing I5. Bar 30 is recessed to receive a rotatable screw 33 which is held against 4 endwise movement relative to the bar and'which meshes with a gear 34' rotatably mounted in the housing 28. Gear 34 is splined on a shaft 35 axially held by but rotatable with respect to and depending downwardly .from the housing, I5: Thus upon rotation of shaft 35 bar 30 is moved inwardly or outwardly while an adjustment of the location of the range of such movement of the bar may be effected by rotating screw 33, The latter adjustment is made in resetting the machine to handle stock of different size and it should be understood that screw"33 is normally locked against rotation. Mounted in a thimble 36 depending downwardly from the principal body portion of the housing 28 is a collar 31 also splined on shaft 32. Collar 31 carries a pair of diametrically opposed pivot pins for mounting toggle links 38 and 39. Referring to Figure 6, clamping shoes 46 and 4| are slideablymounted in suitable openings provided in the housing 28 and these shoes are engaged by and'are adapted to be moved outwardly by the toggle links 38 and 39, respectively, into pressure engagement with the columns II and I2, respectively, whereby upon rotation of shaft 32 means is provided to securely lock the housing 28 against vertical sliding movement on the columns II and I2.

Extending across the-top of the machine and journaled in suitable supports I5I and I52 extending upwardly from the housings I5 and I6 is a shaft .42 on which is keyed a cam 43 having operative relation with a lever35' keyed to the top end of the spline shaft 35 whereby the latter is rotated in response to rotation of the shaft 42. Shaft 42 also mounts a second cam 44 which has operative relation with a. crank 32 ,keyed to the top of spline shaft 32 whereby shaft 32 may also be rotated in response to rotation of shaft 42. Suitable driving mechanism, not shown, is provided to rotate shaft 42 back and forth through approximately a 270 total range and, inpractice, means is provided to'vary the periodicity of this oscillation as well as to interrupt this oscillation under either manual or automatic control. The

a normal cycle of operation is such that when the blade 36 is in retracted position by operation of the spline shaft the shaft 32 is in such position that the toggle links 36 and 39 are straightened whereby the housing 28 is securely clamped to the columns II and I2. Shaft 35 now operates to move blade 36 inwardly and upon the inner edge of the-blade engaging'the top of the stack below the top sheet which is thereby separated as illustrated in Figure 5, shaft 32 rotates to break the toggles thus releasing the clamps 46 and M and permitting the housing 28 to drop a distance represented by the space between the top surface of the blade 36 and the upper guide surface 29. Immediately thereafter shaft 32 reverses to again clamp the housing 28 to the columns II and I2 after which shaft 35 operates to retract the blade 36. As the blade clears the stack it drops slightly by gravity in its guide into position to enter below the next lower sheet in the stack. It should be observed that this mode of operation permits the separating blade 36 to be lowered intermittently in accordance with the spacing of the adjacent sheets in the stack and in this manner normal tolerances in the thickness of the stack cannot effect such accumulative error in the positioning of the separating blade as would interfere with the consecutive separation of a uniform number of sheets. This results fromthe fact that the respective thicknesses of the consecutive sheets determines directly the extent of the downward increments of movement of the housings 28. As shownin Figure 1, an identical separatin assembly is provided on the right side of the machine.

The means provided to lift the sheets separated by the blades 30 from the bulk stack supported on rack I8 and to raise such sheets to four vertically reciprocable parts 45, 46, 41 and 46 one of which is slideably mounted on each of the four square columns I3 and I4. The square nature of columns I3 and I4 holds the parts 45-48 against rotation. Each of the parts 45, 46, 41 and 48 carries a spring pressed lifting latch 49 shown in Figures 3 and 4. Parts 45, 46, 41 and 48 are each made of two pieces adjustable with respect to each other whereby adjustment may be made for different size sheets as will be understood. Provision is made to raise and lower each of these parts in unison and in timed sequence with respect to the operation of the separating mechanism previously described. Such raising and lowering means includes a pair of drums 56 and SI keyed on the lock'shaft 42.

. Secured to drum 56 and encircling the same in one direction is a chain 52 (Fig. 3) which passes over an idler 53 journaled in housing I6 and over idler 51 is connected to-part 48 while a four chain 58 secured to and encircling drum in the opposite direction and entrained over idler 59 is connected to part 45. All 'such connections between the chains and parts are accomplished by providing each of the parts with an aperture through which extends freely the assov ciated chain, the bottom end of the same having attached thereto a weight 58 (Figure 2) which may engage an undersurface of the part. {The function of the weights 50 is to maintain the chains taut regardless of the positions of the parts 45-48. As shown in Figures 2 and 6 housing 28 has integral wings 5| and 62 which partially encompass the columns B and l4 and which are arranged to be engaged by lower surr top sheet feeding device is operative regardless.

faces of the parts 45-48. It should be apparent that upon oscillation of shaft 42 parts 45-48 will be raised in unison a sufllcient distance to transfer the successive sheets separated from the bulk stack by the blades 30 to the under side of the auxiliary stack 25. The extent of downward movement of the parts45-48 which carry the latches 49, however, is predetermined by the position of the housings 28. Thus latches 49 descend only sufliciently to enable their operative tapered edges to engage below the sheet separated by the separating apparatus. As apparent from Figures 1 and 3, levers 26 and 21 are engaged by upper surfaces of the parts 45 and 48 as these parts approach their upper limit of travel so that fingers 22 and 24 (Figure 4) are retracted, in proper timed sequence, to permit the sheet being elevated to be added to the bottom of stack'25. At this time the auxiliary stack is, of course, supported on the latches '49 but upon the start of downward movement of these latches the cams I22 in housings 2i and 23 begin to move to release the fingers 22 and 24 to allow the projecting edges thereof to again engage the bottom surface of the auxiliary stack.

The individual sheets are fed successively to the feed line from the top of the auxiliary stack 25 and to separate the top sheets from the auxiliary stack proper I provide a pair of suction cup assemblies 64 which are carried on a bar 65 spanning the housings l5 and I5. Referring to Figure '7, each of the assemblies .54 comprises a cylinder 66 which is closed: at both ends and has a fiuid inlet 61 at its lower end and a vent 68 open to the atmosphereat its upper end. Slideably mounted in cylinder 66 is an inner cylinder 69 enclosing a piston III which is attached to a rod H carrying a suction cup 12 at its lower end. An opening 13 through rod H and piston I8 provides communication between the space within cup 12 and the. space within cylinder 59 above .piston 10. An aperture 14 is provided in the upper portion of the side wall of the cylinder 59 and a cooperating aperture 15 is provided in the upper portion of the side wall of the cylinder 56. Ports 6'! are connected with a source of fluid pressure through a valve, not shown, operated in accordance with the operation of the machine or equipment to which the sheets are to be fed. At the start of a cycle of operation cylinder 69 is inlowermost position as indicated in dotted ,brings the leading edge portion of. the sheet into contact with a driven magnetic roll 16 to which the sheet is attracted and still further upward movement of cylinder 69 brings apertures I4 and 15 into register which breaks the vacuum thus releasing the cup. Roll 16 is 'now' free to advance the spaced sheet-under guide 11 into a pair of pinch rolls 18. After the sheet clears the top of the stack 25 the above mentioned valve operates to release all pressure from the ports 61 and the cup "then fall .down into engagement with the next succeeding top sheet of the stack 25. It should be apparent that this of changes in the elevation of the to'p of the auxiliary stack 25. As will presently appeal this feature is highly advantageous.

To provide for the uninterrupted feeding of the sheets through the pinch roll 18 even during the time required to place a new stack of sheets on the rack formed of the brackets I8 the mechanism employed to transfer the sheets from the top of the main bulk stack resting on the brackets l8 to the bottom of the auxiliary stack 25 and driven by the shaft 42 as described above is operated at a speed slightly in excess of the demands of a machine or equipment to which the sheets .are supplied so that normally auxiliary stack 25 contains a predetermined minimumnumber of sheets. Upon interruption of the transfer apparatus as is required in replenishing the stock on the brackets 18 the number of sheets in the stack 25 diminishes but the supply thereon is slowly brought back to normal upon the resumption of the operation of the transfer apparatus by reason of this greater speed of operation. To limit the height of auxiliary stack 25 I provide .a limit switch 19 which, through suitable conreplenished. To effect thi mode of operation a depending link 80 is pivotally mounted on each of the two housings 28 and these links are arranged to be rotated inwardly by knobs 8i readily accessible from the front of the machine. When so rotated inwardly they are in the paths of travel of shoulders 82 projecting from the parts 45, 45,

' 41 and 48 so that upon the next upwardstroke lines and if now fluid pressure is admitted through inlet 6! cylinder 58 is moved upwardly thus expanding the space in cylinder 89 above of these parts as results from the pulling action 'of the chains 52, 54, 56 and 58 the complete separating mechanism including the two housings 28 and all appendages thereof will be moved to upper position. Amanual switch 83 ,is provided to interrupt operation of shaft 42 and by opening this switch at the time the parts and housings reach the upper end of .their stroke such parts and housings will be held in upper position by the chains 52, 54, 56 and 58 coupled with the now immobile shaft 42 thereby leaving the rack l8 clear for the replenishment of the stock thereon.

Upon the switch then being turned on the transfer mechanism resumes its operation to replenish the now diminished stock in the stack 25. The

' operation of the machine illustrated in the draw- 7 8 45-48 these fingers wardly sufllcient to position below the side edge -parts during the excess plurality of sheets in auxiliary'stack which is normally supported on fingers 22 and 24 and that there is 'a'pile of sheets in the main stack resting on bracket shaft 42 results in the following sequence of operations. 'When shaft 42 is at the limit of its clockwise travel, as viewed in Figure 2, the auxiliary stack 25 is supported during the prior upward movement of the parts 49 raised'the previously separated top sheet of the lower or main stack into engagement with the bottom sheet of the upper or auxiliary stack and beyond thus lifting the auxiliary stackfree'of the fingers 22 and24. Such upward movement is sufilcient to enable the sheet being added to the bottom of the auxiliary stack to pass up above and beyond the fingers 22v and At this time the latter are in retracted position by reason of the actuation of the lever arms 28 and 21 by the upward movement of parts 45 and 48. a

As the shaft 42 beginsto rotate in a counterclockwise direction, as viewed in Figure 2, the parts 45- 48are lever arms 28 and 21 are allowed to tilt down- .relieve cams I22 thereby 18, the periodic'oscillation of on the fingers ,49 since lowered in unison and, first, the

1 bracket So that housings 28 to which links 88 are attached will be raised-free and clear of bracket I8.- Switch "83 is used to stop irotation or oscillation of shaft -42' when all the parts are This clears and holds clear the space for insertion of a new rack or stack of sheets on the l8. It should be observed that the slotted nature of the assembled bracket I8 is such that the fork of aconventional shop lift truck may be employed to load the rack of sheets on the bracket.

. Upon re-actuation of switch Bland release of links 88 normal operation of the machine is automatically-resumed.

It should be particularly observed that during stock replenishment in the-manner outlined above there needbe no interruption whatever in the feeding of sheetsfrom the top of the auxiliary stack by means of the periodically actuated vacuum lifters 84, magnetic roll I8, and pinch rolls 18. As heretofore explained the frequency of actuation of the valve, not shown. controlling allowing fingers 22 and 24 to move into supporting portions of the descending. auxiliary stack 25. Upon continued downward movement of parts 45-48 the fingers 49 lower away-from the bottom of the auxiliary stack which then rests on fingers 22 and 24. Downward movement of parts 45-48 is arrested by the stops 8|, 62 on housings 28 but before such downward movement is stopped the spring actuated fingers 49 will have snapped over the outer edges of the which top sheet has already been separatedby the blades 38. Shaft 42 always progresses through its full cycle of course, regardless of the extent of vertical travel of the parts 45-48, the

chains 52, 54, 56, 58 simply sliding through these travel and being maintained taut by the weights 88. Thus, after shaft 42 reverses and after the chain slack is taken up p the weights 88 engage parts45-48 to raise the same in unison to lift and add another sheet to the bottom of the auxiliary stack in the manner described immediately above.

During the time that the parts 45-48 are elevated and are lowering the fingers 49 the cams 43 and 44 operate through spline shafts 32 and 35 to first actuate clamps 48 and 4|, then to withdraw or retract the blades Sit-allowing them to drop slightly by gravity into position for entry below the top sheet of the main or lower stack-then to reinsert or move the blades 38 inwardly to separate the top sheet from this stack, and thereafter to release the clamps 48, 4| to allow the housings 28 to drop by gravity an interval determined by the vertical clearance in guides 29, as explained above. Cams '43 and 44 are so designed that this cycle is fully completed before the parts 45-48 are brought to rest on stops 61, 82 regardless of variations in the height of the main or lower stack. a

As explained above. the auxiliary stack 25 is normally replenished from below at a rate greater .than the rate of feed from the top of the auxiliary stack so that normally a full component of sheets appears in the auxiliary stack, the limit switch 19 operating to maintain the component n'umber substantially constant. If now the main stack is depleted the links 88 may be swung inwardly for engagement by shoulders 82 on parts 41 and 48 top sheet of the main stack the flow of. air to units 84 is somewhat less than the frequency of oscillation of shaft 42 so that upon resumption of feed from the main stack the partially depleted auxiliary stack will be slowly replenished to its full complement of sheets.

The above specifically described embodiment of the invention should be considered'as illustrative only as obviously many changes may be made therein without departing from the spirit or scope of the invention. Reference should therefore be had to the appended claims in determining the scope'of the invention.

What I claim is:

1. Sheet feeding apparatus comprising in combination a bulk stock rack,'a support for an auxiliary upper stack of sheets above said rack, means above said support to separate individual I sheets from the top of said auxiliary stack and to thereafter movethe same may from said auxiliary stack, a sheet separating device-arranged to follow the location of the. top of a lower stack ,.of sheets mounted on said rack'and operative to separate the top sheets thereof in succession. a vertically reciprocable transfer apparatus operative to lift the separated sheets from the top -of the lower stack to the bottom of the upper stack, and means on said device to limit the downward movement of said transfer apparatus.

2. Apparatus according to claim 1 further including means effecting downward movement of said device in each cycle of operation a distance equal only to the thickness of the sheet separated by said device during said cycle regardless of variations in the thickness of successive sheets in said lower stack 3. A sheet separating device of the stack top take-off type comprising in combination a vertically extending member, a support slideably mounted for vertical movement on saidmember, means to clamp said support to said member, a separating tool, said support carrying a horizontally disposed guide for slideably receiving said tool, said tool having a knife edge for entering below the bottom surface of the top sheet of the stack, means to operate said clamp and to move said tool outwardly and inwardly of said stack in sequence, means to lower said tool when outwardly ofsaid stack, and means to momentarily release said clamping means while said tool is in inward position.

4. A sheet separating device of the stack top take-off type comprising in combination a support, a stack rack, a support mounted for vertical movement relative to said rack, an elongated in uppermost position.

separating tool, a horizontally disposed channel in said support for slideably receiving said tool,

said channel having upper and lower surfaces spaced a distance equal to the vertical dimension of said tool plus approximately the thickness of the sheets to be separated, means to slide said tool in said guide inwardly and outwardly of the stack, and means to prevent lowering movement of said support when said tool is clear of the stack but permitting free lowering movement of said support when said tool is engaged with the stack.

5. A device according to claim 4 further including adjustable means to vary the spacing of said upper and lower surfaces whereby the extent of vertical movement of said tool relative to said support in each cycle of operation may be varied.

6. A sheet separating device of the stack top take-off type comprising in combination a support mounted for vertical movement downwardly along said stack, a movable sheet separating blade carried by said support, means to move said blade inwardly and outwardly of the stack, and means to lower said support a distance equal substantially only to the thickness of the sheet or sheets to be separated during each such cycle of movement of said blade.

7. Sheet feeding apparatus comprising in combination a bulk stack rack to receive a lower stack of sheets, a sheet separating device of the stack top take-01f type to separate successively the top sheets of said stack from said stack, retractable means supporting an upper auxiliary stack of sheets, vertically reciprocable means for transferring the separated sheets from the top of the lower stack to the bottom of the upper stack, means operable synchronously with said transferring means for retracting said retractable means whereby the sheet or sheets being transferred may be added to the bottom of said auxiliary stack, and means to supply individual sheets in succession from the top of said auxiliary stack.

8. Sheet feeding apparatus comprising in combination a, bulk stack rack to receive a lower stack 10 of sheets, a, sheet separating device of the stack top take-off type to separate successively the top sheets of said stack from said stack, means to support, an upper auxiliary stack of sheets, means to feed individual sheets off the top of said auxiliary stack, means to transfer the sheets separated from the lower stack to the'bottom of said auxiliary stack, and means to move said device to upper position and to maintain said device and said means to transfer in upper position whereby the supply of sheets on said rack.may

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 420,194 Gauchot Jan. 28, 1890 1,388,161 Blaine Aug, 23, 1921' 1,739,153 Laxo et a1 Dec, 10, 1929 2,094,826 Seybold Oct. 5, 1937 2,161,124 Babicz June 6, 1939 2,170,422 Novick Aug, 22, 1939 2,178,783 Egger Nov, 7, 1939 2,184,296 Goepel et a1 Dec. 26, 1939 2,204,985 Foweraker June 18, 1940 2,214,896 Baker Sept. 17, 1940 2,253,556 Christensen Aug. 26, 1941 2,294,297 Heckman Aug. 25, 1942 FOREIGN PATENTS Number Country Date Germany Jan. 27, 1930

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