US3355165A

US3355165A - Fabric stretching and/or alternatelyreversing mechanism for separating fabric pieces from a stack thereof

Info

Publication number: US3355165A
Application number: US449460A
Authority: US
Inventors: Wyndham F Southwell; Wehrmann Nicholas
Original assignee: L AND L Manufacturing Inc
Current assignee: L AND L Manufacturing Inc
Priority date: 1965-04-20
Filing date: 1965-04-20
Publication date: 1967-11-28
Anticipated expiration: 1984-11-28
Also published as: GB1128349A

Description

3,355,165 -HEVEBSING MEG Nov. 28. 196 w. F. SOUTHWELL ETAL F'ABH l C STRE'I'CHINU AND/0R ALTERNATELY HANISM FOR SEIA RATING FABRIC PIECES FROM A STACK THEREOF Filed April 20, 1965 7 Sheets-Sheet 1 INVENTORS WYNDHAM F.SOUTHWELL NICHOLAS WEHRMANN ATTORNEYS Nov. 28. 1967 W. F. FABRIC S'IRETCHING AND/OR AIJTERNATELJY FOR SEPAHATING FABRIC PT Filed April 20, 1965 7 Sheets-Sheet FIG.

FIG. 3

ullmlh u INVENTOR WYNDHAM E SOUTHWELL NICHOLAS WEHRMANN J 777, M M, ATTORNEYS v- 1967 w. F. SOUTHWELL ETAL 3,355,165

FABRIC STRETCHING AND/0R ALTERNA'I'ELY"REVERSING MECHANISM FOR SEPARATING FABRIC PIECES FROM A STACK THEREOF Filed April 20, 1965 7 Sheets-Sheet 3 INVENTORS WYNDHAM F. SOUTHWELL NICHOLAS WEHR MANN Nov- 28. 1967 w. F. soumwsu. ETAL w 3,3 I FABR 1C STRETCHING AND/OR ALTERNATELYREVERSING MECHANISM FOR SEPARATING FABRIC PIECES FROM A STACK THEREOF Filed April 20, 1965 7 Sheets-Sheet 4 FIG. 6

95 IOIEF] AIR IN INVENTORS WYNDHAM F SOUTHWELL NICHOLAS WEHRMANN A TORNEYS Nov. 28. 1 w. F. SOUTHWELL ETAL 3,355,165

FABRLC STRETCHING AND/OR ALTBRNATELYREVERSING MECHANISM FOR SEPARATING FABRlC PIECES FROM A STACK THEREOF Filed April 20, 1965 7 Sheets-Sheet 5 INVENTORS WYNDHAM F. SOUTHWELL NICHOLAS WEHRMANN ATTORNEYS Nov. 28. 1967 F. SOUTHWELL ETAL 3,355,165 FABRIC STRETCHING AND/OR ALTERNATELY-REVERSING MECHANISM FOR SEPARATING FABRIC PIECES FROM A STACK THEREOF Filed April 20, 1965 7 Sheets-Sheet 6 FIG. 9

79G 79 SB LSA m I33 B1 LS LSA2 FIG. 11

LSB2 205 LSA2 265 270 INVENTORS WYNDHAM F. SOUTHWELL BY NICHOLAS WEHRMANN ATTORNEYS United States Patent 3,355,165 7 FABRIC STRETCHING AND/OR ALTERNATELY- REVERSING MECHANISM FOR SEPARATING FABRIC PIECES FROM A STACK THEREOF Wyndham F. Southwell, Wilkeshoro, and Nicholas Wehrmann, North Wilkesboro, N.C., assignors to L & L Manufacturing, Inc., a corporation of Delaware Filed Apr. 20, 1965, Ser. No. 449,460 12 Claims. (Cl. 27112) This invention relates to means for separating fabric pieces from a stack thereof, and has for its objects the provision of such mechanism which is particularly arranged for overcoming the natural tendency of stacked fabric pieces to cling to each other and which, for example, may form a part of means for withdrawing fabric pieces one-by-one from the top of a stack thereof; and, independently of or in combination with the foregoing, of gripping mechanism adapted to pick up and withdraw fabric pieces one-by-one from a stack thereof but in such a manner that certain, but not all, of them may be deposited with a different side up than the side which was uppermost in the stack.

We have found that the tendencies of a fabric piece to cling to a fabric piece next below it may be overcome with great ease and certainty by mechanism including 1 means to engage the upper surface of the top piece of a stack toward each of opposite edges of the piece and means to move an engaging portion of at least one of said means toward its respective edge so as to stretch the fabric therebetween, and thereby displace the uppermost piece generally horizontally thruout most of its extent, for example; this displacement serving to positively break the clinging action of the two pieces thruout most of their area of contact, and thus greatly assisting the separation of the uppermost piece. In certain instances, if desired, any undissipated clinging tendency which remains after the stretching may be broken as by an air blast. The invention finds a veryimportant application in the separation of pieces of knitted fabric from a stack thereof.

We have also found that the reversal of certain of the pieces being separated from a stack (as, for example alternate pieces in a stack formed by cutting a stack of tubular fabrics interiorly of its edges so that a particular face of the upper-most piece is up whereas the corresponding face of the next piece is down) can be performed with a high degree of effectiveness by mechanism wherein the .timing of the release operations on picked-up sheets is varied depending on the order of different sheets in a stack.

Particularly satisfactory results in both instances may be obtained by mechanism comprising at each side thereof one of a pair of gripping elements, and the invention in its more specific aspects contemplates the provision of such mechanism for both purposes. A particularly satisfactory form of gripping elements are elements rotatable on parallel axes and having convex axially-extending frictional surfaces adapted to be pressed against the upper fabric piece of a stack and there rotated.

Such elements may be carried on a single head, and means may be provided to cause relative separative movement between such a head and a stack-support as by means such as exemplified herein or means as exemplified in our copending application Ser. No. 412,103 filed Nov. 18, 1964.

The invention accordingly comprises the features of construction, combination of elements, and arrangements of parts, which will be exemplified in the constructions hereinafter set forth and the scope of the application of which will be indicated in the claims.

ice

For a fuller understanding of the nature and objects of the invention, reference should be had to the following detailed description taken in connection with the accompanying drawings, in which:

FIGURE 1 is a perspective view of one form of mechanism embodying the invention;

FIG. 2 is a view of the lefthand portion of the opposite side thereof;

FIG. 3 is a top view of the portion of the mechanism shown in FIG. 2;

FIG. 4 is a sectional View on an enlarged scale on the line 44 of FIG. 3;

3 FIG. 5 is a similar view along the line 55 of FIG. FIG. 6 is a horizontal section on the line 6-6 of FIG.

FIG. 7 is a diagrammatic showing of the air pressure control means;

FIG. 8a is a schematic view of the pick-up head in pick-up position at the beginning of a first cycle of operations;

FIG. 8b shows the pick-up head beginning to move a fabric piece over the bafile plate;

FIG. shows the pick-up head after the release of the forward portion of the piece onto the conveyor when the forward gripping means is still above the conveyor, altho on its way back to pick-up position;

FIG. 8d shows the pick-up head just after the release of the rear portion of the fabric piece for forward movement by the conveyor;

FIG. 8e shows the pick-up head in position at the beginning of a second cycle of operations for picking up a piece of material which, before the cutting on the stack, formed the lower half of a piece of tubular fabric;

FIG. 8 ShOWs the pick-up head in the process of removing the second piece of fabric;

FIG. 8g shows the pick-up head after the release of the forward portion of the fabric before the pick-up head has reached the conveyor;

FIG. 8h shows the pick-up head moving the fabric over the baflie plate so as to turn it over prior to the release of the rearward gripping means;

FIG. 8i shows the gripping head over the conveyor just after the rearward gripping means has released its end of the fabric;

FIG. 8i shows the just-released fabric piece being moved forward in a position on the conveyor following the piece which was previously picked up and deposited;

FIG. 9 is a perspective view showing the operating cam arrangement at a time when the beam is in the position of FIG. 8a in the first cycle;

FIG. 10 is a detail View on an enlarged scale of one of the operating cam arrangements;

FIG. 11 is a diagrammatic view showing the timing of the operations involved at a time when the beam is in the position of FIG. 8a in the first cycle; and

FIG. 12 is a circuit diagram.

In the form of apparatus exemplified, there is provided a frame generally designated by the numeral 10. A beam 12 is swingingly supported by shaft 13 journalled to the frame. Mounted on the shaft 13 and fixed to the frame 10 is asprocket 14 over which there extends a chain 15 extending to a sprocket 16 fixed on a shaft 17 rotatably supported from a cross-piece 18 near the free end of the beam 12. Fixed to the shaft 17 is an operative head 20 which, due to the provision of the chain and its sprockets, is caused to turn with respect to the beam and is thus prevented from turning with respect to the floor when the beam is swung. The head 20 will thus have its lower side down and will be in the same relationship to the earths gravity at all times, so as to pick up a fabric piece, transport it, and release it while the fabric piece hangs below the head.

To the beam there is fixed a crank arm 22 to which is pivoted one end of a link 23 the other end of which is pivoted to the end of a crank arm 24 which is fixed to a shaft 25, the etfective lengths and relations-hips of the

elements

22, 23, and 24 being such as to move the beam 12 and head 20 to carry the head 20 between an operative position X and a release position Y (FIGS. 1 and 2). The shaft 25 is driven, by means including a speed-reduction means 26, a speed-control means 27; a belt 28 and a pulley 2811, at a constant predetermined speede.g. ten to thirty (preferably eighteen) revolutions per minute from a motor 29 by transmission means including a belt 30 running on

pulleys

31 and 32. In the present instance there is employed a one-third horsepower motor.

The operative head 20 (which in the exemplified form of construction serves as a pick-up head) carries, respectively, at two positions spaced from each other and differently spaced from the shaft 13 when in pick-up position, a gripping means 33 and a gripping means 34 (which in the exemplified form of construction are in the form of pick-up means) adapted to engage and be pressed against the uppermost fabric piece 38 of a stack 39 of (in the present instance) single-ply fabric pieces cut from a stack of tubular knitted fabric. In the present instance, the gripping means 33 is so positioned as to engage the fabric piece 38 near one edge thereof (the edge furthest from the shaft 13 in the present instance), and the gripping means 34 is so positioned as to engage the fabric piece 38 near the opposite edge thereof (the edge nearest the shaft 13, in the present instance); it being important, when gripping means 33 and 34 are utilized to overcome tendencies of the fabric piece 38 to cling to the fabric piece 40 below it by stretching the fabric piece 38 between them, that as great a proportion of the fabric as practical lie between the gripping means 33 and the gripping means 34.

The stack 39 is carried by a support table 41; and a foam rubber cushion 42 or the like is preferably provided between the two.

As exemplified, the gripping means 33 comprises a rotatable element 43 adapted to contact the uppermost piece of fabric on the stack 39 near that edge of the stack which is furthest from the shaft 13, and the gripping means 34 comprises a rotatable element 44 adapted to contact the same uppermost piece of fabric near the opposite edge of the stack (which is nearest to the shaft 13), and there is provided means to move the fabric-contacting portions of the

elements

43 and 44 away from each other. To this end, the element 43 is formed with a pinion 47 meshing with a rack 48, and the element 44 is formed wit-h a similar pinion 49 meshing with a rack 50, and

solenoids

53 and 54 are provided to draw these racks toward each other. Oppositely-acting

solenoids

55 and 56 are provided to move them away from each other. The

solenoids

53 and 54, respectively, rotate the elements 43 and 4-4 sufficiently to move the

lower surface portions

57 and 58 thereof away from each other when they are in engagement with the uppermost piece of fabric and to draw the engaged portions of this piece of fabric apart and to break, to a very great extent, its tendency to cling to the piece below it.

In order to assure a positive separative action of the

elements

43 and 44 and to provide for a pick-up action thereby, the

surface portions

57 and 58 are formed as friction surfaces, as by providing sandpaper on those portions (or, as exemplified, on the entire peripheral surfaces of the cylinders which constitute the elements 4-3 and 44). Sandpaper of various grades may be used. Papers carrying silicon carbide abrasive of thirty grit, sixty grit, one hundred grit and five hundred grit, and alumina abrasive of thirty-six grit and one hundred and fifty grit have, among others, given satisfactory results. In general it may be stated that the coefficient of friction between the operative surface of the pick-up element and the particular fabric pick up should be greater than the coefficient of friction between two layers of fabric.

While in some instances the friction surfaces of pick-up elements such as 43 and 44 will be all that is needed to assure the picking up of the portions of the fabric which are engaged thereby, it is very important in certain instances, and desirable in others, that the fabric be positively pinched as an initial or other part of the pick-up action. To this end the gripping

means

33 and 34 as exemplified are formed respectively with pinching

elements

59 and 60 respectively which provide, respectively, surfaces 61 and 62 toward which the

surfaces

57 and 58 move when the

elements

43 and 44 are rotated to stretch the fabric, to draw portions of the fabric into the space between the

surfaces

57 and 61 at one side and between the

surfaces

58 and 62 at the other side, and to pinch these fabric portions suificiently so as to assure that they will be positively held by the gripping

means

33 and 34 until the individual release of each individual gripping means (or the joint release of the two gripping means if so desired).

In order to energize the

solenoids

53 and 54 there are provided electrical means including the respective switches LS1 and LS2 adapted to be closed by upwardly-movable, downwardly-spring pressed, dependent rods 63 an 64 respectively which normally extend downwardly far enough so that the switches LS1 and LS2 will be closed when the upward pressure of the fabric on bot-h rods is enough to assure that the

elements

43 and 44 will effectively press down upon the fabric.

In order to blow air upon and thru the uppermost piece of fabric (as when it has been stretched by the rotation of

elements

43 and 44 or at some other desired stage, as for example on release of one or both of the gripping means), there is provided blower means comprising, in the present instance, a source'of air under pressure,

pipes

65 and 66, and downwardly-and-inwardly-directed discharge openings 65a and 66a, respectively.

As exemplified, the table 41 is provided with an adjustable air-cushion support by means of a piston having a head 67 in an air cylinder 68. Air under a cushioning pressure (of, e.g., eight pounds per square inch) is introduced below the piston from a pipe 69 controlled by a normally closed valve 70, and above the piston head by a pipe 71 controlled by a normally closed valve 72 and connected with a normally closed pressure-relief valve 74 having an adjustable bleeder end 75 which, as exemplified, is adjusted for total opening of the pipe 71. As will be seen, when the valves and 74 are opened, the table 41 will be moved upwardly. The setting of the bleeder end should be such that the air above the piston head 67 will be exhausted at least fast enough (much more than fast enough, as exemplified) to compensate for the removal of the fabric pieces one-by-one from the stack 39 and to cause the table to rise between one movement of the pick-up head to position X and a successive (but not necessarily immediately successive) such movement thereof at least enough to bring the now-uppermost layer to a position in the general vicinity of the position which a recently removed layer has occupied. When, as exemplified, the table moves upwardly at a speed faster than enough to compensate for the removal of the fabric pieces, the upward movement will open a limit switch 76 to close the valves 70 and 74 (while the valve 72 and a normally closed relief valve 77 from pipe 69 remain closed) when the upper surface of the uppermost layer of fabric on the stack moves the switch arm 78 of the switch 76, which arm is set to move when the fabric has compressed to a desired degree under it. Thus, as fabric pieces are removed, the table 41 and the stack 39 will rise whenever the upward pressure on the switch-arm 78 is sutficient to operate the switch 76, so as to bring additional fabric pieces one-by-one to the same horizontal plane or to occasionally bring the top of the stack to the general vicinity of such a plane (as may be desired) for convenient pick-up by the head and withdrawal by the withdrawal means comprising the beam 12 and the head 20. Some depression of the top layer of the stack by the gripping means is desirable in order for them to grip the fabric effectively, so that the switch arm 78 should be arranged to be operative only when the top of the stack lies above the lowest position of the pick-up elements. In the present instance, action of the limit switch 76 is replaced, or substituted for, in a part of a cycle before the head 20 depresses the top of the stack, by the activation of a switch 79 by a cam 79:: on shaft 25, which switch 79 performs a similar function to the function of the switch 76, but is independent of the action of the height of the stack.

When the table itself rises to an extent such that all or most of the fabric pieces of a stack thereon have been removed therefrom, the table 41 will contact a limit switch 80 to open valve 72 and relief valve 77 (which has a controlled bleeder end 81 similar to the end 75), and to close

valves

70 and 74, to permit the piston and table to drop under control of valve 81 to a position wherein a new stack, such as that shown at 39a, may be placed on the table. The activation of the limit switch 80 also causes the circuit of the motor 29 to be broken to discontinue movement of the beam 12. The switch 80 should be operative while there is still some depressible support, such as the cushion 42 or a few fabric pieces, between the table and the operative position of the jaws. As soon as the new stacks 39a is properly in place on the table, a push button 32 may be pressed to operate a switch PBI to restore the valves to their normal positions and to cause the circuit of the motor 29 to again be closed. An additional push button 83 may be provided to close a switch PB2 to perform the function of the switch 80 when necessary at any time.

The pipes 69 and 71 are supplied thru a pipe 85 when a gate valve 86 is open. Pipe 85 extends to a main airpressure supply line 87 which also supplies a pipe 88 when a gate valve 89 is open. The pipe 88 has two branches one of which is controlled by a switch 91. These branches are shown at 92 and 93; the latter being the one controlled by the switch 91. Air fiows thru pipe 92 to

pipes

65 and 66; this air discharge being timed to occur, in the exemplified operation, at a time when the head is about to lift the uppermost fabric piece. The branch 93 is controlled by a normally closed valve 94 which is opened in response to the closing of a switch 91 by crank arm 24 to pipe 92. At a time under control of valve 94 air is blown thru pipe 93 to discharge nozzle 95 which directs air downwardly upon a fabric piece released in a particular one of the manners hereinafter described as it is moved beneath the nozzle 95 by a conveyor to arrange and smooth the fabric piece as it passes thereunder. In the operation in question (hereinafter further described) the fabric will now carry a small flap 96, formed by the pinching action of the gripping means and now pointing rearwardly of the direction of movement of a conveyor surface on which the fabric piece lies; and the jet of air from the nozzle 95 is first ejected after the rear (free) end of the flap 96 has passed beneath the nozzle, so that the spreading fan of air above the surface will bend the flap forward and straighten and smooth the fabric.

The air pressure normally provided beneath the piston head serves as a cushion which yields as the head 20 swings into contact with the top of the stack, and facilitates the gripping of the top layer without gripping the second layer.

The air flow thru

pipes

65 and 66 is distributed to the openings 65a and 66a, respectively, thru chambers 97 and 98.

In FIGS. Sta-8i there is exemplified a two-cycle se quence of operations whereby alternate ones of fabric pieces cut from a stack of right-side-out circularly-knit tubular fabric interiorly of the edges thereof are trans ferred to a conveyor with the same side up as when they were in a stack, whereas the intervening ones are turned over in the process of being transferred to a conveyor, so that all the pieces will be the same side up when they are on the conveyor, to have a binding tape sewn to the uniformly uppermost right side thereof, for example. In cycle 1, exemplified in FIGS. 8a8d, the

relays

53 and 54 are substantially simultaneously energized when, because of the nature of the stack and the small areas of the ends of the

rods

63 and 64 in relation to the

lower surface portions

57 and 58 of the

rotary elements

43 and 44, the

surface portions

57 and 58 are in sufiiciently firm engagement with the fabric to move the (end) edge portions of the fabric away from each other, by movement of the

portions

57 and 58 toward their respective edges. As the upper fabric piece 38 becomes pinched by the gripping means 33 and the gripping means 34, the rotation of the crank arm causes the head 20 to swing past a curving bafiie plate 99 and above a conveyor 100 (which has a higher coefiicient of friction than the fabric). When the head is above the conveyor (near the beginning of its return movement, as exemplified), the solenoid 54 is de-energized and the solenoid 56 energized to swing the surface portion 58 inwardly away from the surface 62 to release the grip of the gripping means 34 on the forward portion of the fabric piece 38 and allow the released end of the fabric piece to contact the surface of the conveyor which tendsto carry it forward in the direction of the arrow. The rear end of the piece 38 is still held by the gripping means 33, but is released thereby after the just released forward end of the piece has dropped on the conveyor. In cycle 2, exemplified in FIGS. 8e8j, the fabric piece 40 is picked up the same way as the fabric piece 38, but its forward end is released by the gripping means 34 early enough so that this end will fall on the stationary baffle plate 99 (rather than conveyor 100) by which bai'iie plate the fabric piece 40 will be turned over before it reaches the conveyor 100. The gripping means 33 releases the rear end of the fabric piece while this rear end is over the conveyor and before the forward end reaches the conveyor, so that the fabric piece 40 will now lie upside down on the conveyor. The flap 96 may be flattened out as indicated above.

In order to space the pieces of fabric evenly, the release of each piece 38 by the gripping means 33 is postponed until it is spaced rearwardly of a preceding piece 40 the same amount that a succeeding piece 40 will be spaced from it. The release of the fabric piece 38 (in cycle 1) accordingly does not occur until the head 20 has started its return movement (see FIGS. 80 and 8d).

In order to open the

respective valves

94, 72, 77, 70, and 74, there are provided

solenoids

101, 102, 103, 104, and and there is provided a solenoid 106 to open a valve 107 to admit air thru a pipe 108 to a nozzle 109 positioned to discharge air laterally over a point on the conveyor (beyond the nozzle 95) where a rufiied fabric is detected by a photoelectric cell device 110-111 to close a limit switch LS9 to energize solenoid 106, so as to blow off from the conveyor any piece of fabric which has been picked up or deposited improperly to such an extent that the fabric piece does not lie sufiiciently flat on the conveyor to be properly received by a sewing machine 112 or other fabric handling or treating device.

Flow thru the

pipes

65 and 66 is, respectively, controlled by

valves

115 and 116 operated, respectively, by

solenoids

123 and 124.

In addition to the cam 79a for operating the switch 79, the shaft 25 carries a cam 131 for operating switch 91 to actuate solenoid 101, the

cams

133 and 134 to actuate switches LSA and LSB which energize

solenoids

123 and 124, respectively. Driven by belt 135 from shaft 25 at half the speed thereof is a shaft 136 carrying

cams

137, 138, 139, and 140 which open normally-closed switches LSA1, LSBl, LSA2, and LSB2. Switches LSBl and LSAI actuate

solenoids

56 and 55, respectively, in the first operating cycle, whereas these respective solenoids are oper- 7 ated by switches LSB2 and LSA2 in the second operating cycle; and all at points in the cycle as indicated in detail in FIG. 11, and all as further described hereafter.

The operating voltage for the unit is connected to

parallel lines

200 and 201 between which are connected in series lines 213214-215216. The two switches, LS1 and LS2, are connected in series in line 215. There is placed in parallel with switches LS1 and LS2 a set of normallyopen contacts 216a operated by a relay CR1, which is connected across the coil of solenoid 53. These units are fed by

lines

216 and 201. Release coil 55 in a line 217 is controlled by a normally-closed set of contacts 217a operated by relay CR1. These components are connected by lines 200217201. The release of the first sequence is controlled by the two normally closed limit switches, LSA1 and LSA2. These are connected by lines 200-213 214. The purpose of this portion of the circuit is to control at a regulated squence the pickup and release of a piece of fabric by the activation and subsequent deactivation of the gripping means 33. The two

solenoids

53 and 55 are so connected into the circuit that the energization of the solenoid 53 will cause the element 43 to rotate in a clockwise manner (FIG. 5) and the energization of the release coil 55 (after the de-energizing of the coil 53) will rotate the element 43 counterclockwise.

The actuating

rods

63 and 64 of limit switches LS1 and LS2 are, respectively, placed adjacent to the pick-up means 33 and pick-up means 34. When both switches are closed pressure of the fabric against the rods, current is allowed to energize coil 53 and relay CR1. The closing of relay CR1 closes CR1 contacts 216a shunting limit switches LS1 and LS2, and thus locking the circuit in. Element 43 has rotated and is now holding the fabric. At the instant CR1 coil and coil 53 are activated, the (CR1) normallyclosed contacts 217a open, allowing the coil 55 to deenergize. The function of limit switches LSAl and LSA2 (in the next step of the circuit) is to release the pick-up

coils

53 and 54 at the appropriate time as called for by the .position of

cams

137 and 139, respectively, that strike and open these limit switches.

Line 200 connects to normally closed contacts LSBl and line 219 connects normally-closed contacts LSB2 to LSB1. Line 200 connects contacts LSB2 to (CR1 normally-open) contacts 220a. The other side of contacts 220a of CR1 are connected by line 221 to pick-up coil 54 in parallel with relay coil CR2. Both these coils are connected to line 201. Line 200 connects to normally closed contacts 221a or CR2 relay, the other side being connected by line 222 to release coil 56. The other side of the coil 56 is connected to line 201. In the control of pickup means 34 and its release, the operation is similar to that of pick-up means 33 except for the means of actuation. When hold-in coil CR1 is energized by the closing of limit switch LS1 and limit switch LS2, the act of normally-open contacts 22011 of CR1 relays are closed allowing current to flow and energize pickup coil 54. Further, coil CR2 is also energized.

As above indicated, in order that a more positive detachment may be obtained, compressed air may be employed. Air jets 65a and 66a are respectively placed in close proximity to pick-up

devices

33 and 34. These jets are independently controlled

solenoids

123 and 124, respectively. The sequence of opening and

closing solenoids

123 and 124 are controlled by

cams

133 and 134 respectively, opening the normally closed limit switches LSA and LSB or permitting them to close.

In order to obtain the desired amount of air for either cycle, a timer is used, the function of which is to control the length of time that either of

solenoids

123 and 124 are to remain open. Limit switch LSA is connected by line 200 and is parallel with a set of hold-in normallyopen contacts 222a on a relay CR3. Line 23 connects to relay CR3. The normally-closed contacts 222k of a time delay relay, of relay CR3TD is placed between line 223 and a line 224 which connects, in parallel, the coil of relay CR3, the solenoid coil 123, and the coil of the time delay relay CR3TD. The other side of all three coils are interconnected by line 201.

Upon closing of LSA by the action of the cam 133 on this limit switch, current is allowed to flow thru the circuit and energize the coils CR3 (solenoid) 123, and CR3TD. The normally-open contacts of CR3 immediately close, thus shorting out the normally-open contacts of LSA, and thus allowing the flow of current to continue thru the circuit. At the same time that CR3 coil and solenoid 123 coils were energized, CR3TD, which is the time delay coil, is also energized. Upon conclusion of the time set on CR3TD time delay coil, its contact 222!) situated between

lines

223 and 224 will open, thus disconnecting this circuit and setting it up for the next cycle.

Limit switch LSB with normally opened contacts is activated by earn 134. Across the normally-open contacts LSB there is placed in parallel a set of normally-open contacts 224a of a relay CR4 which are connected by

lines

200 and 225. CR4 hold-in coil is connected in parallel with the coil of the solenoid 124, and the coil of the time delay relay CR4TD, by line 201 and a line 226. The normally-closed contacts 226a of CR4TD time delay relay completes the circuit by being connected to lines 225 and 226. The function of this circuit is identical to that as described for the circuit required to operate solenoid 123.

Lines

200 and 201 have inserted therebetween a line 228 containing normally-open switch 91 and solenoid 101 for closing valve 94. Between lead 200 and a conducting element 229 there are connected in parallel closable normally-open contacts PBZ under control of push bupton 83; normally open hold-in contacts 229a of coil CR t and closable normally open contacts of tabledown hold-in switch and from element 229 to lead 201 in parallel solenoid 102, solenoid 103 and line 230. Line 230 contains the coil CR6 in addition to a normally closed switch PB1 openable by push button 82. Thus, the closing either of switch 80 or of switch PB2 operated by push button 83, will not only

open valves

72 and 77, but will also energize coil CR6. The energization of coil CR6 will close contacts 229a of CR6 and will at the same time open normally closed contacts 23% of CR6. A line 235 contains the normally-closed contacts 230s of CR6 and a coil CR7. When switch PB1 is opened coil CR6 is deenergized, thus allowing its contacts 230C to close and energize coil CR7.

Connected to lead 200 are normally open contacts 235a of CR7, the other side of which are connected by line 236 to one side of the motor, the other side of the motor and line 201 being interconnected to another set of normally open contacts 236a of CR7 by line 237 completing the circuit thru the motor. Thus, the opening of switch PB1 will result in starting up the machine again, as well as in permitting the closing of

valves

72 and 77.

Solenoids

104 and 105 are in parallel lines respectively running to lead 201 from line 2371: running from lead 200 and containing a normally-closed switch 230b (which is opened by the energization of coil CR6), switch 76 and switch 79; and, thus,

valves

70 and 74 will be open only when switch 230]) is in its normally closed position and when switches 75 and 79 are also held in their normally closed position.

In the event of a poor pick-up and subsequent deposit of fabric on the conveyor, the ruffled piece of fabric is detected by photoelectric device -111 to close limit switch LS9, which energizes solenoid 106, causing a laterally-directed jet of air to remove the piece of fabric in question. Line 200 connects to the normally open contacts of limit switch LS9, which interconnects with solenoid 106 by line 238. Solenoid 106 is connected to line 201 to complete the circuit thru solenoid 106 to pass air thru said nozzle 109.

Various features set forth in our copending application Ser. No. 412,103 may be incorporated in mechanism embodying the present invention.

tion or shown in the accompanying drawings shall be in- I terpreted as illustrative and not in a limiting sense.

We claim:

1. Mechanism for separating pieces of fabric from a stack thereof comprising means to engage and exert frictional pressure on the upper surface. of the top piece of a stack near each of opposite edges of the piece, and means to move'an engaging portion of each engaging means toward its respective edge while exerting said frictional pressure to stretch the upper piece of fabric therebetween and thereby loosen its engagement with the piece below it, wherein each of said engaging means is formed with a fabric-engaging portion having a convex longitudinallyextending fabric-engaging frictional pressure surface and wherein said moving means is arranged to move said surfaces along curved paths.

2. Mechanism as in claim 1 wherein a fabric-pinching means is associated with each of said engaging means and wherein during the action of said moving means each of said pinching means is disposed with an operative surface slightly spaced inwardly from its one of said edges and slightly nearer said one of said edges than its associated frictional pressure surface and adapted to cooperate with said associated frictional pressure surface to grip fabric therebetween when said engaging means are moved by said moving means.

3. Mechanism for separating pieces of fabric from a stack thereof comprising means to engage the upper surface of the top piece of a stack near each of opposite edges of the piece, means to move an engaging portion of each engaging means toward its respective edge to stretch the upper piece of fabric therebetween and thereby loosen its engagement with the piece below it, a pair of fabricgripping means each comprising one of said engaging means, stack supporting means, means for mounting said gripping means, means operative after said moving means to cause a relative separative movement of said supporting means and said mounting means for effective relative separative movement of an engaged piece and the stack, means for releasing said gripping means, and means including the releasing means and means controlling the timing thereof for depositing a fabric piece with the same side up a when it was on the top of the stock and for depositing another fabric piece with the opposite side up than when it was on the top of the stack.

4. Mechanism as in claim 1 wherein each of said gripping means comprises a gripping element having a convex fabric-engaging frictional surface, and wherein said gripping elements are rotatable on parallel axes by said moving means.

5. Mechanism for transferring pieces of fabric from a stack thereof comprising a pair of relatively widely spaced rotatable gripping elements each having an axiallyextended convex fabric-engaging frictional surface, means having gripping surfaces spaced at a greater distance apart than the first-mentioned surfaces and relatively slightly s aced from said first-mentioned surfaces to provide therewith fabric-gripping means when said first-mentioned surfaces are rotated, means to move saidgripping elements against the uppermost piece of fabric on a stack and to rotate said gripping elements, means to support a stack of fabric pieces, means to cause a separating action of said gripping elements and said supporting means after the operation of said rotating means, and means for effecting controlled releasing operations of said gripping elements.

6. Mechanism for transferring pieces of fabric from a stack thereof comprising a stack support, a conveyor, draw-over means between said conveyor and the position of a stack on said stack support, means to pick up a 10 piece of fabric from the top of the stack at a position toward said conveyor and means to pick up said piece of fabric at a position remote from said stack support, means to operate both said pick-up means, means to move both said pick-up means from a position in proximity to said stack to a position in which they are over said conveyor,

means to release the first-mentioned pick-up means when it is over said conveyor, means to thereupon release the second-mentionedpick-up means, means to return both said pick-up means and to operate them again, means to .cause a repeated operation of said means to move both said pick-up means from a position in proximity to the stack to a position in which they are over said conveyor,

means to release the first-mentioned pick-up means before a piece held by said second-mentioned pick-up means is drawn over said drawn-over means, means to release the second-mentioned pick-up means when it is over said con veyor, and means to thereupon return both said pick-up means.

7. Mechanism for transferring pieces of fabric from a stack thereof to a reception means, comprising means to pick up a piece of fabric from the top of a stack and t0 deposit it with the same side up as when it was on the top of the stack and to pick up a succeeding piece of fabric from the top of the stack and to deposit it with the opposite side up than when it was on the top of the stack, said pick-up means comprising means to engage the upper surface of the top piece of a stack near an edge of the piece, means to engage the top piece of a stack at a place spaced from the aforesaid means, and means to move an engaging portion of at least one of the engaging means away from the other of said engaging means to stretch the upper piece of fabric therebetween and thereby loosen its engagement with the piece below it.

8. Mechanism for transferring pieces of fabric from a stack thereof to a reception means, comprising means to pick up a piece of fabric from the top of a stack and to deposit it with the same side up as when it was on the top of the stack and to pick up a succeeding piece of fabric from the top of the stack and to deposit it with the opposite side up than when it was on the top of the stack, said pick-up means comprising a pair of pick-up elements, and means to operate said pick-up elements to pick up a fabric piece at the same time and to release it at different times.

9. Mechanism for transferring pieces of fabric from a stack thereof to a reception means, comprising means to pick up a piece of fabric from the top of a stack and to deposit it with the same side up as when it was on the top of the stack and to pick up a succeeding piece of fabric from the top of the stack and to deposit it with the opposite side up than when it was on the top of the stack said pick-up means comprising a pair of pick-up elements rotatable on parallel axes and each having a convex axially-extending frictional surface, and means to rotate said pick-up elements at the same time and to release them at different times.

10. Mechanism as in claim 9 wherein said releasing means is arranged to release one of said pick-up elements at an earlier time after it has picked up each of certain of the fabric pieces and at a later time after it has picked up each of other of said fabric pieces.

11. Mechanism for transferring pieces of fabric from a stack thereof to a reception means, comprising means to pick up a piece of fabric from the top of a stack and to deposit it with the same side up as when it was on the top of the stack and to pick up a succeeding piece of fabric from the top of the stack and to deposit it with the opposite side up than when it was on the top of the stack, said pick-up means comprising a pick-up element having a convex axially-extended frictional surface adapted to move in one direction for a pick-up operation and in the other direction for the release operation, and means for causing movement of said pick-up element in the first direction when 1 1 said surface is in engagement with a piece of fabric at the top of the stack and in the other direction when said surface is at a remote point.

12. Mechanism for transferring pieces of fabric from one position to another position which comprises pick-up means operative on one portion of a fabric, pick-up means operative on another portion of a fabric, means to cause both said pick-up means to pick up a fabric with one of its sides up, means to deposit a thus-picked-up fabric with said side up and including means for eifectuating a particular timing of the release of at least one Of said pick-up means, and means to deposit a thus-picked-up fabric with an opposite side up and including means for effectuating 12 a different timing of the release of at least one of said pick-up means.

References Cited UNITED STATES PATENTS 793,009 6/1905 Miller 27118 850,313 4/1907 North 271-65 2,256,852 9/1941 Schubert 27162 X 2,799,499 7/1957 Perry et 'al. 271-26 3,083,961 4/1963 Arbter 271- 33 3,168,307 2/1965 Walt0n 'et a1. 271-26 3,176.979 4/1965 Engelmann 27118 ALLEN N, KNOWLES. Primary Examiner.