US3034631A

US3034631A - Coated sheet inserter

Info

Publication number: US3034631A
Application number: US825840A
Authority: US
Inventors: Anthony W Pomper
Original assignee: JOHN WALDRON CORP
Current assignee: JOHN WALDRON Corp
Priority date: 1959-07-08
Filing date: 1959-07-08
Publication date: 1962-05-15
Anticipated expiration: 1979-05-15

Description

May 15, 1962 A. w. POMPER COATED SHEET INSERTER 6 Sheets-Sheet 1 Filed July 8, 1959 l n'wENToR ANTHONY W. POMPER BY Q r a ATTORNEYS May 15, 1962 A. w. POMPER COATED SHEET INSERTER 6 Sheets-Sheet 2 M SD 4 INVENTOR ANTHONY W. POMPER Filed July 8, 1959 BY Q ATTORNEYS May 1962 A. w. POMPER' 3,034,631

COATED SHEET INSERTER BY =2 ATTORNEYS May 15, 1962 A. w. POMPER COATED SHEET INSERTER 6 Sheets-Sheet 4 Filed July 8, 1959 INVENTOR ANTHONY W. POMPER ATTORNEYS y 1962 A. w. POMPER 3,034,631

COATED SHEET INSERTER 6 Sheets-Sheet 5 Filed July 8, 1959 143 1- INVENTOR ANTHONY W POMPE/i BY Q r a ATTORNEYS y 15, 1962 A. w. POMPER 3,034,631

COATED SHEET INSERTER Filed July 8, 1959 6 Sheets-Sheet 6 INVENTOR ANTHONY m POMPER rfih ATTORNEYS niteSttes This invention relates to apparatus for handling coated sheets and more particularly to such apparatus for accepting relatively rigid sheets, freshly coated on one side, accelerating their speed of travel to increase the spacing between sheets, introducing the sheets horizontally and successively between the wickets of a travelling conveyor and rapidly decelerating each sheet after it has entered between wickets to prevent damaging its entering edge at the wicket bottom.

It is a general object of the present invention to provide a novel and improved sheet inserter for the purpose specified in which sheet acceleration and deceleration are achieved in novel manners.

More particularly it is an object of the invention to provide a sheet inserter capable of rapidly accelerating coated, rigid sheets beyond their delivery travel rate for individual introduction between wickets of a conveyor as each sheet accepting wicket approaches the horizontal as it turns about the conveyor end pulley, together with means for rapidly decelerating the sheet between th wickets to stop it before its leading edge contacts the wicket bottom.

An important object of the invention resides in the construction and operation of the sheet decelerator mechanism arranged to engage the sheet at substantially its accelerated speed after its leading edge has entered between successive moving wickets and to then decelerate it to zero speed as it travels a distance substantially less than wicket depth.

Another important object of the invention resides in the control of the sheet deceleration by a harmonic motion imparted to the decelerating apparatus in synchronism with the rate of sheet delivery to the wicket conveyor.

Still another important object of the invention resides in the provision of safety means to prevent damage to the sheets in the event of slow release thereof by the attaching means for holding the sheet during deceleration.

An important feature of the invention consists in the use of suction cup means to engage and hold the sheet for deceleration and the use of positive air pressure to insure quick release thereof. 1

Another and alternative important feature of the invention resides in the use of magnet means for engaging and holding the sheets during the deceleration.

A further important object of the invention consists in the provision of track means to guide the sheet holding device, mechanism to raise and lower the track in unison with sheet movement to provide return clearance for the holding device, and valve means actuated by.

said track movement to control, in proper timed relation, the vacuum and pressure line connections to the sheet holder.

Other and further objects and features of the invention will be more apparent to those skilled in the art upon a consideration of the following specification and accompanying drawings wherein are disclosed two exemplary embodiments of the invention with the understanding that such changes and modifications thereof, as fall within the scope of the appended claims, may be made ther in without departing from the spirit of the invention.

In said drawings:

FIG. 1 is a side elevation of the coated sheet inserter illustrated as positioned between a sheet coater and a tent or 1C wicket conveyor arranged to transport coated sheets, delivered to it by the inserter, through a heated drying oven;

FIG. 2 is a side elevation of the coated sheet inserter alone and on an enlarged scale showing, in dotted lines, some of the internal components;

FIG. 3 is a top plan view of the sheet inserter on the same scale as FIGURE 2;

FIG. 4 is a fragmentary, longitudinal, vertical section, on a much larger scale, taken on line 44 of FIG. 3 showing the accelerating and decelerating suction cup for the sheets, and the carriage and track for the same together with cup driving means and raising and lowering mechanism for the track;

FIG. 5 is a plan view of the suction cup, its carriage and certain of the drive mechanism therefor;

FIG. 6 is a right end elevation of the suction cup, its carriage and the drive mechanism therefor, taken on line 6-6 of FIG. 4 looking in the direction of the arrows;

FIG. 7 is an enlarged, transverse, vertical section, taken on line 7-7 of FIG. 4, illustrating the fulcrum mechanism for the cup-carriage drive-lever and the means for delivering suction and pressure through it to the cup;

FIG. 8 is a view like FIG. 7 of the upper end of the cup-carriage drive-lever showing its connection to the cup drive link, the section being taken on line 88 of FIG. 5;

FIG. 9 is a perspective view of the suction cup, its carriage and the valving mechanism for the cup;

FIG. 10 is a side elevation, partly broken away, of the assembly of FIG. 9;

FIG. 11 is a top plan view of the suction cup carriage, with dotted line illustrations of the air and vacuum passages therein, the view being taken on line 11-11 of FIG. 10;

FIG. 12 is a fragmentary vertical, sectional view taken on line 12-42 of FIG. 11 showing the vacuum passage through the wrist pin connecting the carriage to the link;

FIG. 13 is an exploded view of the oscillating valve for connecting pressure or vacuum to the suction cup;

FIG. 14 is a vertical, sectional view through the valve assembly taken on line 1414 of FIG. 11 showing the valve porting; and

FIG. 15 is a perspective view of a permanent magnet structure which may be used alternatively with the suction cup where the sheets to be handled are of magnetic material.

In order to rapidly dry a coating freshly placed on one side of a sheet of sufficient rigidity to stand on its edge, it has heretofore been known to introduce the sheets successively onto the wickets of a conveyor for transportation through a drying oven and to feed each sheet onto a wicket as the latter approaches the horizontal when turning about one of the end drums of the conveyor system. Delivery of the sheets successively to the wickets was by belts, tapes, or chain-link conveyors which fed the sheets substantially against the bottom supports of the wickets, which latter acted as stops to limit their movement. However, with the advent of demands for higher speeds and the practical development of high speed coating apparatus, the old system became useless since the velocity of the sheets travelling horizontally on the flexible conveyor devices became so great that the leading edges of the sheets were damaged when they struck the stops at the bottoms of the wickets. Additionally, with the sheets following each other in rapid succession with small spacing between sheets, the leading edge of the following sheet would interfere with the trailing edge of the sheet just loaded on the wicket. Speeding-up the sheets to travel at a rate greater than their movement through the coating apparatus, and thus to achieve wider spacing between successive sheets, only increased the velocity and hence the damage when the sheet was stopped at the wicket bottom.

It is the purpose of the present invention to provide apparatus capable of accelerating the sheets substantially beyond the speed of travel through the coating apparatus, and preferably in stages so as to introduce them with extreme rapidity between the wickets and at the same time achieve adequate spacing between successive sheets to prevent interference. The mechanism is capable of engaging the under-surface of the sheet with sufficient friction so that deceleration at an extremely high rate can be applied to the sheet just prior to its bottoming in its wicket and damage to the leading edge thereof avoided while interference between the trailing edge of the sheet on the wicket and the advancing succeeding sheet is prevented.

For a better understanding of the invention reference should first be had to FIG. 1 illustrating at the coated sheet inserter of the present invention, arranged between the delivery conveyor 26 of any satisfactory form of high-speed sheet coater 27 and a conventional wicket conveyor 28 which is adapted successively to receive the sheets in their horizontal travelling position, one per wicket, move them to a substantial vertical position and advance them through an oven 29 where they are exposed to heated air or gas, infra-red rays and/ or other means for heating, evaporating and/or drying or setting the coating which has been applied to the sheets in the coater 27.

To provide synchronization between the rate of feed of apparatus 25 and wicket conveyor 28, shaft 30 is shown, representative of means synchronizing the two drives and for connecting them, whereby one may receive its rate from the other to insure that one sheet is fed to each wicket at the appropriate time as it is advancing to the horizontal position. Thus at 31 a wicket is advancing toward the transporting position after having received a sheet 32 While in or below the horizontal position, while wicket 33 is advancing to receive the following sheet now being forwarded toward the space between wickets 31 and 33 and moving along the spaced rails 34 between which the wickets pass, as better illustrated in FIG. 3. A second pair of closely spaced sheet support bars 35 of lesser length is shown for center support of the sheets as they move into the wicket.

The wickets are attached to appropriate chains 36 which are guided over suitable supporting rollers and turn about end sprockets 37 at the receiving end and corresponding sprockets at the opposite end. Each wicket, as seen in FIG. 3, is an assemblage of metal bars or wires to provide appropriate support beneath the sheet to keep it from bending or buckling and shaped to have the deep indentation 39 in its outer center for clearance about the support bars 35 and other parts. Adjacent its connection to the carrying chains, each wicket has two or more stops 40 in the form of small hooks against which the leading edge of the sheet is stopped and on which it rests when the sheet is brought nearly to the vertical position, as shown by wicket 31 with just sufficient rearward inclination to keep the sheets from being in unstable equilibrium.

FIGS. 2 and 3 show the sheet inserter to he a selfcontained unit, except for the synchronizing drive means, supported from the floor 42 by suitable legs 43 equipped with jack screws 44 for changing the elevation of the top surface of the machine for appropirate alignment with the delivery conveyor of the coater and the axis of the pivot for the turn-around sprocket 37 of the wicket conveyor.

The principal strength members of the inserter are the side plates 45 appropriately connected together by cross members as shown, and braced and reinforced where necessary. These plates provide bearing means for a plurality of

cross shafts

46, 47, 48 and 49. An extension unit 50 is slidably attached to the side plates by means of horizontal rods 51 secured to the lower portion of the end member of the extension at 52 and slidable in bearings 53 and 54 on the side plates 45 whereby the extension may be withdrawn to a maximum position, as shown in FIGS. 2 and 3, or collapsed to occupy but little more length than the side plates. This permits adjustment to accommodate the feeder to various spacings between the conveyor of the coater and the wicket conveyor. This extension is fitted with a shaft 57 at its outer end and mounted thereon are four crowned

pulleys

58, 58 and 59, 59. A pair of correspondingly crowned

pulleys

60, 60 are mounted on shaft 49 at the forward end of the insetter, and between

pulleys

58 and 60 are stretched a pair of conveyor tapes 61 adapted to be driven, by means not shown, and to accept sheets as illustrated at 32 in FIG. 1 from the conveyor tapes of the coater delivery mechanism 26. A second or intermediate pair of tapes 63 extend between pulleys 59 on shaft 57 and pulleys 64 on intermediate shaft 46. This shaft also carries pulleys 65 over which the belts 61 pass in their movement between

pulleys

58 and 60.

Automatic take-up means comprising a plurality of pulleys as seen in FIG. 2 is provided on the sheet inserter and its extension to take care of the excess belt lengths which exist when the extension is at other than its maximum outward position, and many devices are known for this purpose so a description is unnecessary.

The belts or tapes 61 and 63 accept sheets 32 directly from conveyor 26 of the coater and preferably at substantially the same speed, although in some cases it may be desirable to accelerate the sheets slightly by the action of tapes 61 and 63. In any event, since these tapes are of fabric and have no great adherence to provide tractive effect,

pulleys

58 and 59 and the others illustrated on

shafts

46, 47 and 49, if desired, may be permanently magnetized for co-operation with ferrous sheets for holding them tightly in contact with the tapes for positive drive. To maintain the sheets in proper alignment side guide rails, shown at 67, may be provided spaced so as to permit only slight clearance with the sheet edges and adjustably mounted if desired in order to handle sheets of different widths.

In order to provide greater spacing than exists as a result of the delivery rate from the coater between the trailing edge of each sheet and the leading edge of the following one means is provided to accelerate the sheet movement and this preferably takes the form. of a pair of chains 68 extending from shaft 48, arranged just to the left of shaft 46 where tapes 61 stop, and the two-part shaft 49, each of which is equipped with appropriate sprockets 69 for the purpose. Shaft 48 is driven by appropriate means at a speed considerably in excess of the tape speed in order to accelerate the sheets and separate them to a greater extent. To insure positive synchronization of sheet position with wicket position through the operation of shaft 30 between the wicket drive and the feeder drive, each chain 68 is fitted with one or more lugs 71 extending transversely thereof and above its outer surface whereby as the sheet moves forward on tapes 61 and shortly after its trailing edge leaves tapes 63, these lugs moving more rapidly than the sheet engage its trailing edge and promptly accelerate it to chain speed. The driving lugs 71 do not release the sheet as they move downwardly around their forward sprockets 69 until its leading edge is more than half way advanced over the wicket which will eventually pick it up.

For controlling the sheet in its final movement into the wicket, and to rapidly decelerate it so that the leading edge of the sheet will not be damaged when stopping against the hooks 40 supporting it at the bottom of the wicket, means is provided for grasping the under-surface of the sheet and is driven by an harmonic motion device. The preferred form uses as a sheet gripping means a suction cup having arrangements for connection to a source of vacuum and such cup, as shown at 75, is mounted on a carriage 76, see FIG. 9, equipped on each side with a pair of wheels 77 adapted for guiding it between a pair of grooved tracks 78, the forward ends of which are seen to project to 79 well down into the area swept by the wickets as they come around the end sprocket and each wicket is seen to have its end wire 80 indented as at 81 to provide adequate clearance for the purpose.

Referring now to FIG. 4, the. tracks are spaced at opposite ends by cross members 8 4 and 85, and each of these is supported by a pair of spaced dependent plates 86 mounting transverse wrist pins 87 pivoting them to the end of link '88 at the left and lever 89* at the right. The opposite end of link 88 is fulcrumed at 90 on a block mounted on cross member 91 of the frame. Lever 89 is pivoted intermediate its ends at 92 on a member attached to frame cross-piece 93. The lower end of lever 89 is fitted with lateral pin 94 adapted to operate in cam groove 95 in disc 96 mounted on cross shaft 97, as seen in FIGS. 2 and 4, suitably driven by a chain on sprocket 98 thereon and appropriately timed from other portions of the drive system.

It will be appreciated that the track being pivoted on

links

88 and 89 of the same length and having the same inclination, as shown, will move up and down in a parallel motion under the action of the pin 94 operating in the cam track 95. Also mounted on shaft 97 at the far end thereof is crank arm 100 pivoted to connecting rod 101 whose opposite end is fulcrumed at 102 to oscillate lever 103 pivoted at 104 to a cross member 105 near the bottom of the frame. Lever 103 is connected by link 131 to carriage 76 whereby the latter makes one full stroke between the two positions shown in dotted lines in FIG. 4 for each revolution of shaft 97. The motion imparted to the carriage for the suction cup, because of its source at crank 1011 may be referred to as harmonic motion, starting at the end of each stroke at zero velocity, increasing rapidly to maximum velocity at mid-stroke and then decelerating at an increased rate until the opposite end of the stroke is reached. This action is relied upon to bring the suction cup up to the speed of sheet 32 being driven by lugs 71 on the chains, at which time suction is applied, as will be later described, and the cup is adhered to the undersurface of the sheet by the vacuum thus achieved. The vacuum cup may still be accelerating in a direction toward the wicket whereby the sheet is caused to move with the cup and increase its speed from that imparted to it by the chain drive or the speed of the cup may be at its maximum when suction is applied. At about the time of suction application, the lugs which were driving the sheet move around the front sprockets which separates them from the sheet so that the drive is now solely by the motion of the suction cup '75. When crank 1110 reaches mid-position its speed begins to decrease at an accelerated rate, and as the vacuum cup approaches its maximum forward position the vacuum is released, as will be later described, and air pressure applied to insure separation of the vacuum cup from the sheet while the latter is still moving forward at just sufiicient velocity to insure its lightly engaging the hooks 40 at the bottom of the wicket under its own momentum. The vacuum cup is now returned to its starting position under the action of the linkage just described.

In order that the vacuum cup may be elevated to engage the under-surface of the sheet and be lowered to complete its return stroke without interference with the next advancing sheet (it engages near the trailing edge of each sheet and hence must pass beneath substantially the whole length of the sheet before being raised to engage it), the track on which the vacuum cup carrier travels is raised and lowered by means of lever 89, as previously described, under the action of pin 94 following in the cam groove 95 in rotating disc 96, exactly timed with the movement of the vacuum cup carriage in the fore and aft direction. 1

It will be noted that somewhat more than 200 degrees of cam path 95 is arcuate and from the two ends of this section the path moves inwardly, at the positions 110 and 111 to the maximum inward position 112. At this maximum inward position the track has been moved upward to its fullest extent and the travel of the carriage is just beyond mid-stroke in the forward direction with velocity near maximum and substantially the equivalent of that of the sheet being carried by the chains. As the cup is brought up against the under-surface of the sheet at this maximum elevation of the former, vacuum is applied and the retarding action of the sheet is begun and continued until nearly the end of the stroke, as previously mentioned.

Vacuum and air pressure are supplied to the cup through the driving mechanism for it as follows. In FIG. 4 a vacuum line 115 is shown connected to the lower fulcrum 104 for the oscillating lever 103, and a similar pressure line is also provided. As seen in FIGS. 7 and 8, lever 103 is composed of two

tubes

116 and 117 parallel to each other and the first for vacuum and the second for air under pressure. These tubes are secured into block 118 fulcrumed on pin 119 secured therein and mounted in base 120 secured to cross frame member 105. Each end of the block, in alignment with the bores for supporting pin 119, is counterbored at 121 and 122 and internally threaded to receive a fitting, as seen in FIG. 4, to which a tube or pipe such as 115 is attached, one for vacuum and one for air coming from suitable pump-s for the purpose, not shown. Each counterbore leads into a partial bore 123, 124 in opposite ends of pin 119 and these are connected to its surface by lateral bores, as indicated, which are in alignment with passages 125 and 126, respectively, connecting to the interiors of

tubes

116 and 117 which are thus pressurized while permitted to rock on their pivot. The rocking takes place in bushings such as 127 packed by means of an O-ring 128 and held in position by a pin 129.

At their

upper ends tubes

116 and 117 are fitted into bores in block 1311 whose upper end is divided into two part-s to receive between them the rear end of connecting link 131 which is provided with a pair of parallel,

longitudinal passages

132 and 133, the former for vacuum and the latter for pressure. These are connected to the

respective tubes

116 and 117 by the passages shown in block and the separate passages in wrist pin 134 in substantially the same manner as the arrangement at the lower end of the oscillating lever, whereby the two pressures are communicated through the length of the connecting link, and, by a similar arrangement to that at the bottom of the oscillating lever, the link is connected to the spaced

extensions

135 and 136 from the rear end of carriage 76. Suitable passages in the wrist pin, FIG. 11, connecting the left end of the connecting link between these extensions, provide for vacuum in bore 138 and pressure in bore 139 leading towards the left in the body of the carriage from the wrist pin.

FEG. 12 makes it clear how the vacuum passage 132 is connected to bore 141 in the wrist pin which connects the forward end of the connecting rod to the carriage, and from this bore longitudinal extension 141 extends out through the end of the wrist pin into chamber 142 in extension 136, the end of which is closed by plate 143, and passage 138 is shown in end elevation leading forwardly. This wrist pin is fitted with an O-ring 144 as previously described, and a locking pin 145.

The vaccum cup construction is best seen in FIGS. 9 and 10 where a flat metal plate forms the base on which is mounted a resilient sheet, such as rubber or the like, 151, having a large central aperture 152 entirely through it. This aperture communicates with the longitudinal central passage 153 in the cylindrical stem 154 which is secured at right angles beneath the metal plate 150 and is adapted to slide in vertical bore 156 in main member 76 of the vacuum cup carriage and its coaxial continuation in the lower member 157 thereof. The vacuum cup is prevented from rotating about the stem axis by means of guide pin 158 secured to and projecting downwardly from plate 150 and guided in bushed hole 159 in the upper surface of part 76.

The vacuum cup is maintained spaced above the carriage body by means of collar 161, surrounding the stem 154, which limits its lowering toward the carriage and provides a rigid connection between plate 150 and the stem. Below block 157 the stem is surrounded by helical spring 163 whose outer end abuts washer 164 secured against movement off of the stern by means of a cross pin as shown, whereby the vacuum cup is normally held in its lower position. This arrangement, however, permits the vacuum cup to be lifted for a limited distance should the sheet be engaged and lifted by a wicket which may be slightly in advance of its normal timing. The cup is released from the sheet, normally before the latter is lifted, by the action of a valve now about to be described which cuts off the vacuum and applies air pressure to insure cup release.

The valve in question is positioned between

passages

138 and 139 in carriage block 76 and vertical passage 166 therein which has its continuation 167 horizontally in block 157 until it meets the enlarged counterbore 168 in the upper face of this block and surrounding the reduced diameter 169 of the vacuum cup stem. A radial bore 170 extends from the stern bore 153 to the surface of the reduced diameter portion whereby communication is had between 167 and the interior of the vacuum cup.

The block 76 is transversely bored as at 175, see

FIGS. 11 and 14, to receive valve body 176, of the same length as the width of the block, and, comprising an open-ended tube having radial bores 138 and 139 which register with the ends of the vacuum and

pressure passages

138 and 139 in the carriage block 76 in which the sleeve is tightly pressed. This valve body has central passage 177 directed downwardly in alignment with and connected to passage 166.

An adjusting sleeve 180, closed at one end and longitudinally bored from the opposite end, has a close fit within the valve body bore and is angularly adjustable therein, within limits, to change the timing of application of vacuum and pressure to the cup in the event that different length sheets are being handled by the Wicket loader. For the purpose of this adjustment the solid end 181 projects outwardly, as best seen in FIG. 11, Where it may be appropriately shaped to receive a wrench or the like to rotate it slightly for change in adjustment. Sleeve 180 has radial through

passages

182 and 183 of a length about equal to the diameter of

passages

138 and 139 but of limited circumferential extent as seen in FIG. 14. They both communicate with the central bore 185 therein which has a working fit with the valve spool 186. Midway longitudinally between the

slots

182 and 183 and aligned with passage 177 there is a through slot 187 extending a sufficient distance circumferentially around the bore to remain in register with 177 under any adjusted condition.

The valve spool 186 which has a rotary working fit in the longitudinal bore of the adjusting sleeve is provided with a longitudinal central bore 191 closed at the ends and having a large central opening 192 passing through its wall in alignment with slot 187 in the adjusting sleeve so that the spool interior is in communication therewith in all adjusted positions of the spool.

The wall of the valve spool 176 has a pair of radial slots therein, 194 and 195, circumferentially displaced from each other so that when one registers with slot 182 in the adjusting sleeve the other one is out of register with 183, and vice-versa, whereby oscillation of the valve spool 186 through an angle of to 50 degrees will achieve a change from vacuum to pressure which will feed through opening 192 in the spool, slot 187 in the sleeve and passage 177 in the valve body and then to 166 and 167 and to the chamber 168 surrounding the reduced diameter of the suction cup stem to supply either pressure or vacuum thereto in accordance u with the setting of the valve spool. This spool has a large disc 196 at one end with a cam follower 197 rotatably mounted on pin 198 eocentrically positioned on disc 196.

A spring, not shown, normally maintains the valve spool with its follower 197 in the position illustrated in FIG. 9, somewhat above the horizontal center, or neutral position as shown in :FIG. 10, where it provides air pressure to the cup chamber 152. This condition exists during the first half of the cup forward stroke and for all of its retraction stroke.

To connect vacuum to the cup, as it is lifted into engagement with the under-surface of the sheet moving forwardly at the same rate as the cup, the under-surface of one of the stationary sheet supporting bars 35, seen best in FIGS. 3, 4 and 6 projecting into the deep notch in each wicket as it passes, is made use of to cam down follower 197 until slot in valve spool 186 registers with slot 183 in the valve adjusting sleeve. This disconnects pressure from the suction cup by shutting off the fiow of air between 194 and 182 and supplies vacuum thereto so that the cup is immediately adhered to the under-surface of the sheet and is ready to apply its retarding force as it decelerates on the later half of its stroke toward the wicket carrier.

As the carriage carrying the vacuum cup advances towards the end of its stroke and the position where it releases the sheet while the latter still has slight forward momentum to complete its entrance into the wicket, downward movement of its track has begun to draw it away from the cup which is still attached to the sheet and in so doing allows the cam follower 197 to return towards the vacuum cut-off and air pressure supply position shown in FIG. 9. As soon as air is supplied the cup is promptly released from the sheet and is drawn down to its stop position on top of the carriage under the action of its spring 163. As previously pointed out, should the wicket be slightly bent in a direction so that it lifts the sheet slightly sooner than it should, additional movement of the cup upwardly prior to sheet release may take place. For the time following the suction cut-off and application of pressure air to release the cup this air flows until the vacuum is again applied after the cup has been retracted and advanced for about onehalf of its forward stroke.

Previously it has been pointed out that there is no real necessity for magnetizing the pulleys carrying the tapes since synchronization has been adequate without this arrangement which, of course, permits the operation of the apparatus on nonferrous sheets. Under some conditions where the apparatus is designed solely for operation with ferrous materials, magnetic means for engaging the sheet rather than the suction cup may be resorted to, and in FIG. 15 is shown the alternative form of apparatus which makes use of permanent magnets instead of suction cup means. This greatly simplifies the construction of the carriage driving mechanism since it does not have to be constructed with passageways through the various rods, links, and flexible joints, and all of these can be made simple as is shown in the solid metal link 200 which is substituted for the hollow connecting rod 131 in the preferred embodiment. It is connected by pivot 201 to a carriage 202 having a pair of rollers 203 on each of its opposite side faces for travelling in the tracks 78 similar to those used in the prior construction.

The carriage mounts a simple box-like structure having vertical side walls 205, more widely spaced than the rollers 203, and connected together at opposite ends by the transverse struts 206 which support between them the longitudinal bars 207 of nonmagnetic material, the upper surfaces of which are flush with the edges 208 of the side walls of the carriage.

A pallet structure 210 in the form of an inverted U of sheet metal is arranged to slide vertically between side members 205 and has mounted on each of its side walls a pair of pins 212 on each of which is rotatably mounted a cam follower 213. Each follower moves in a groove 214 in the side wall 205 acting to guide the pallet vertically.

The pallet carries a plurality of elongated magnet bars 215 interleaved between the non-magnetic bars 207. The pallet is spring-loaded to withdraw the magnets below the surfaces of stationary bars 207, the lower edges of the inverted U-shaped pallet stopping against the floor of the carriage to limit this movement. Under these circumstances the carriage may be lifted until bars 207 engage the under-surface of the sheet without attaching itself thereto, but when the pallet is lifted in respect to the carriage the magnets rise above the non-magnetic bars and engage the sheet to firmly grip it so that deceleration can be achieved as explained in connection with the principal embodiment.

Various means may be used to engage the cam followers 213 to lift the pallet and its magnets at an appropriate time in the stroke of the carriage to engage the sheet with the same timing as mentioned in connection with the suction cup, and release is effected by having these means disengaged from the cam followers whereupon the springs draw the magnets away from the sheet which cannot follow them because it engages the top surfaces of the non-magnetic bars below which the upper faces of the magnets are withdrawn under the action of the very strong springs acting on the pallet.

Obviously, stationary cam means brought into play by movement of the carriage may be resorted to for lifting the pallet followers, particularly Where aided and abetted by movement of the track on which the carriage travels.

As a further simplification since the pallet is raised and lowered mechanically, the carriage may travel in a fixed track with adequate clearance between the undersurface of the sheet and the top surface of the stationary non-magnetic bars 207 for relative movement-without interference. All the movement required then is now imparted to the pallet which may obviously be done with mechanism nearly identical with that used for raising and lowering the tracks as described in connection with the principal embodiment but modified slightly to achieve raising and lowering at the proper times in the cycle.

Either form of the invention is capable of effectively carrying out the operation of accepting the sheets, painted or otherwise coated on one side, from the delivery of the coating mechanism, accelerating them to provide sufficient separation to prevent interference when the sheets are loaded onto their successive wickets, and capable of applying rapid and effective deceleration so that no matter how high the velocity of the sheet for rapidity of coating, transfer and wicket loading, no damage occurs to the forward edges of the sheets since they are not required to contact the wicket supports to terminate their movement. Thus the sheets are loaded without damage from coating machines capable of supplying sheets at a rate which could not be handled by earlier forms of wicket feeding devices.

I claim:

1. Apparatus for feeding flat, rigid, sheets freshly coated on the upper face and travelling horizontally in their own plane in substantially edge to edge succession, one to each wicket of a travelling conveyor as it rounds the conveyor end pulley and rises toward a horizontal position, comprising in combination, a first travelling belt conveyor means having a linear speed greater than that of the travelling sheets and positioned to receive said sheets to accelerate them and increase their edge to edge spacing, a second travelling belt conveyor means having a constant linear speed greater than the first and sufficient to load the wickets without interference from succeeding sheets but too fast to safely permit the sheet edges to engage the wicket bottoms to stop sheet movement, said second conveyor having spaced lugs to' engage the trailing edge of each sheet and having a discharge end for positioning to release the lugs and deliver said sheets successively only partially entered between conveyor wickets, sheet bottom engaging means, means mounting said engaging means for movement in sheet direction to cause it to grip the underface of each sheet after the latter enters the space between wickets, means to accelerate said engaging means to sheet speed before said gripping and constructed to then rapidly reduce its speed to zero, and means to release said retarding means just prior to sheet bottoming in said wicket.

2. The apparatus as defined in claim 1 in which the sheet retarding means includes a suction cup, a vacuum line connection to said cup, valve means associated and travelling with said cup to control and time the application and cut-off of said vacuum to said cup, and means directly dependent on cup position to actuate said valve.

3. The apparatus as defined in claim 2 in which an air pressure line is also connected to said suction cup, a valve means mounted with said vacuum valve to control time of application and cut-off of said air pressure to said cup, said vacuum valve actuating means being so arranged as to also actuate the pressure valve and mech anism timing the respective valves to open the pressure valve as the vacuum valve closes to release the suction cup hold on the sheet.

4. The apparatus of claim 2 in which the suction cup is oscillated in harmonic motion by components including a hollow link and a tube hinged at one end and pivoted to said link, and means delivering said vacuum to the hinged end of said tube for delivery to said suction cup. 7 5. The combination claimed in claim 1 in which means is provided to synchronize the operation of the travelling belt conveyor means and the sheet bottom engaging means with that of the travelling wicket conveyor.

6. Apparatus for feeding flat, rigid, sheets freshly coated on the upper face and travelling horizontally in their own plane in substantially edge to edge succession, one to each wicket of a travelling conveyor as it rounds the conveyor end pulley and rises toward a horizontal position, comprising in combination, travelling conveyor means having a constant linear speed sufficiently greater than initial sheet travel to load the wickets without interference from succeeding sheets but too fast to safely permit the sheet edges to engage the wicket bottoms to stop sheet movement, lugs on said travelling conveyor spaced to engage the rear edge of each sheet to synchronize its position and movement with wicket succession,

means to withdraw said lugs from the sheet edge on entry of the leading edge between wickets, sheet retarding means to stop sheet movement between front edge entry and bottoming in a wicket comprising sheet bottom gripping means, a carriage mounting said gripping means independent of said travelling conveyor, a track for said carriage, means to reciprocate said carriage in said track parallel to the sheet path and means to raise said track to contact the gripping means and sheet when they are travelling at the same rate and direction, said reciprocating means being arranged to then rapidly retard the carriage to zero speed to stop the sheet before bottoming in the wicket.

7. The apparatus of claim 6 in which the carriage reciprocating means actuates it in harmonic motion.

8. Apparatus for feeding flat, rigid, sheets freshly coated on the upper face and travelling horizontally in their own plane in substantially edge to edge succession, one to each wicket of a travelling conveyor as it rounds the conveyor end pulley and rises toward a horizontal position, comprising in combination, a continuously travelling conveyor means having a constant linear speed sufficiently greater than initial sheet travel to load the wickets without interference from succeeding sheets but too fast to safely permit the sheet edges to engage the wicket bottoms to stop sheet movement, lugs on said conveyor to positively engage the trailing edge of each sheet; means co-operating with said conveyor means to drive the latter so as to synchronize each sheet with the wicket travelling to receive it, means to withdraw said lugs when the sheet has entered the wicket about halfway, sheet bottom gripping means guided in a path and reciprocated at a rate to engage the bottom of each sheet successively when the means and sheet are moving at substantially the same speed and approximately at the time of lug withdrawal and means to progressively retard said sheet gripping means after it engages the sheet so as to stop the sheet just before it bottoms in the wicket moving to receive it.

9. Apparatus for feeding fiat, rigid sheets freshly coated on the upper face and travelling horizontally in their own plane in uniformly spaced close succession, one substantially against the bottom stops of each wicket of a travelling conveyor as the wicket rounds the conveyor end pulley and rises toward a horizontal position, comprising in combination, travelling conveyor means having a linear speed not less than sheet travel speed and positioned to receive said sheets and to continue their horizontal travel, second travelling conveyor means positioned to receive sheets from the first and driven at a constant substantially higher linear velocity, lugs on the second conveyor adapted to engage the trailing edge of each sheet successively to positively accelerate it to the second conveyor velocity, means to synchronize lug position and wicket succession, means to withdraw the lugs after the forward edge of the sheet has entered a wicket, sheet retarding means to substantially stop sheet travel in a distance less than that between sheet entry and bottoming in a wicket comprising means for engaging the sheet bottom at substantially the time of lug withdrawal, a carriage for said engaging means, a track for said carriage, means to reciprocate said carriage in said track parallel to the sheet path when driven by said lugs, means to elevate said engaging means to contact the sheet bottom when the travel rates and directions are substantially the same, and means to progressively retard the rate of travel of said engaging means to stop the sheet jut prior to bottoming in the wicket.

10. The apparatus as defined in claim 9 in which the sheet engaging means is a vacuum cup, a source of vacuum and means dependent on cup position in its movement cycle to apply and shut off vacuum to said cup.

11. The apparatus as defined in claim 10 in which thereis a source of air under pressure and means to supply said air to said vacuum cup just as the vacuum is shut off to release the sheet from the cup.

12. The apparatus of claim 11 in which the vacuum and pressure air are controlled by a valve in said car- 12 riage, means in the carriage reciprocating-mechanism to deliver the vacuum and air to the carriage and the means to elevate said engaging means assists in the change-over from vacuum to air pressure.

13. The apparatus as defined in claim 9 in which the reciprocating means for the carriage is driven in harmonic motion and in which mid-stroke speed is substantially the same as the speed of said driving lugs.

14. Apparatus for feeding flat, rigid sheets freshly coated on the upper face and travelling substantially horizontally in their own plane in close succession one to each wicket of a travelling conveyor as the wicket rounds the conveyor end pulley and rises toward a horizontal position, comprising in combination, a pair of laterally spaced, flexible conveyor means having lugs thereon for engaging the sheet trailing edges successively to accelerate them to a speed to provide additional sheet spacing and too great for stopping by Wicket bottom engagement without damage, means to synchronize said flexible conveyor and wicket conveyor whereby the former feeds sheets successively into the latter, and sheet retarding means working between said spaced conveyor means and having means to engage each sheet bottom near its trailing edge, means to reciprocate said retarding means in harmonic motion with mid-stroke speed substantially that of the travelling sheets, means to efiect engagement of said retarding means and sheet when speeds are substantially equal and means to disengage them when the sheet speed is substantially zero and its leading edge is adjacent the wicket bottom.

15. The apparatus of claim. 14 in which said engaging means is a suction cup and source of vacuum.

16. The apparatus of claim 14 in which said engaging means is permanent magnet means, and mechanism to raise said last mentioned means for engagement and to lower them for disengagement.

17. The apparatus of claim 14 in which disengagement takes place when sheet velocity is just sufiicient to carry the sheet against the wicket bottom without damage thereto.

18. The apparatus of claim 14 in which said sheet engaging and retarding means is mounted on a carriage, tracks for said carriage and means synchronized with the reciprocating means to raise and lower said tracks to aid engagement and disengagement of the sheet.

References Cited in the file of this patent UNITED STATES PATENTS 2,267,710 Ayres Dec. 30, 1941 2,770,346 Oswalt Nov. 13, 1956 2,880,846 Schone Apr. 7, 1959