US2919917A - Sheet distributing machine - Google Patents

Description

Jan. 5, 1960 4 Sheets-Sheet 1 Filed May 24, 1957 u ma W J H a m K .ATTORNEY Jan. 5, 1960 R. J. WORSWICK SHEET DISTRIBUTING MACHINE 4 Sheets-Sheet 2 Filed May 24, 1957 INVENTOR. Hand/d cl P16101111 ATTORNEY Jan. 5, 1960, R. J. WORSWICK SHEET DISTRIBUTING MACHINE 4 Sheets-Sheet 3 Filed May 24, 1957 E IN VEN TOR.

[Yam/d JWazwuia ATTORNEY Jan. 5, 1960 R. J. WORSWICK 2,919,917

SHEET DISTRIBUTING MACHINE Filed May 24, 1957 4 Sheets-Sheet 4 ATTORNH United States Patent .Ofifice 2,919,917. Patented Jan. 5, 196i) SHEET msrrunurnsro MACHINE Ronald J. Worswick, Orlando, Fla., assignor, by mesne assignments, to the United States of America as represented by the Secretary of the Air Force Application May 24, 1957, Serial No. 661,375

3 Claims. (Cl. 271-64) This invention relates to a sheet distributing machine, and more particularly to an automatic machine for sequentially assembling sets of sheets from a plurality of groups of sheets. A group of sheets comprises a stack of identical sheets. A set of sheets comprises one sheet from each of a plurality of groups serially arranged in the form of a book, for example.

An object of this invention is to provide an improved sheet distributing machine which is simple in construction, which occupies a minimum of Space, and which is rapid and highly efiicient in operation.

Another object of this invention is to provide an improved sheet distributing machine which is completely automatic in operation.

A further object of this invention is to provide an improved sheet distributing machine wherein an improved automatic means controls the operation thereof, sequentially, in a step-by-step manner.

A still further object of this invention is to provide an improved sheet distributing machine which will accept, at one loading, a plurality of groups of sheets, and which will automatically assemble said groups of sheets into a plurality of sets of sheets.

A still further object of this invention is to provide an improved sheet distributing machine having means for preselecting the number of sets of sheets to be assembled regardless of the number of sheets in each group.

In accordance with the invention, a plurality of sheet receiving bins are arranged horizontally and an electromagnetically operated gate is disposed at the mouth of each bin. A conveyor means passes sheets individually along a path adjacent the gates and the sheets are selectively intercepted by the gates as they are opened. A feed station accommodates a plurality of groups of sheets in a single stack, and includes means for feeding the sheets individually from the stack to the conveyor means. An electric control system programs the machine to distribute a sheet from each group into each bin and to recycle the machine after each group has been distributed to the bins to commence distribution of the next group.

The novel features of the invention, as well as additional objects and advantages thereof, will be understood more fully from the following description when read in connection with the accompanying drawings, in which:

Figure 1 is a top view of a machine in accordancewith the present invention; I

Figure 2 is a sectional side view of the machine taken along the line 2-2 of Figure 1; p

Figure 3 is a fragmentary side view showing the operation of the gate system of the machine;

Figure 4 is a view similar to Figure 3 showing another phase of the gate operation;

Figure 5 is a fragmentary side View showing details of the sheet feeder mechanism; and

Figure 6 is a schematic diagram of the control circuit of the machine. I Referring now to the accompanying drawing, v,anillustrative embodiment of the invention wilf'be described.

Referring particularly to Figures 1 and 2 of the drawing, a machine in accordance with the present invention includes an elongated frame having a feeder mechanism 11 at one end. The feeder mechanism supports a vertical stack of sheets 13 and feeds them individually to a conveyor which extends horizontally across the top of the machine. The conveyor comprises a plurality of drive rollers 15 and opposing pressure rollers 17 which are horizontally spaced along a conveyor track and carry the sheets 13 between them. A plurality of gates 19 and 21 are positioned horizontally between the rollers 15, and are actuated to intercept and direct individual sheets as they pass along the conveyor track. The gates 21 will be referred to subsequently as shutters, since their function is somewhat different from that of the gates 19. A plurality of bins 23 are disposed beneath the conveyor track to receive the sheets intercepted and directed by the gates and shutters. Each bin is associated with a particular gate and shutter. An overflow bin 25 is positioned at the end of the conveyor track opposite from the feeder to receive excess sheets which are not deposited in any of the bins 23.

The feeder 11 is of a type used commercially for printing machines and the like, and includes a table 31 for a stack of sheets to be distributed. This table is vertically adjustable and self-positioning during running time to maintain the top of the stack at a fixed height. Brackets 33 are provided to apply a light pressure on three sides of the stack in order to maintain the stack in proper align?- ment. The brackets 33 are adjustable so that various sizes of sheets may be accommodated. Pick-up of the sheets is accomplished by hollow metal fingers 35 which are mechanically operated and have vacuum drawn in them by a vacuum system. The pick-up fingers 35 are rigidly mounted on a shaft 37 which extends horizontally perpendicular to the direction of feed of the sheets 13. The shaft 37 is rigidly secured to, and held in parallel alignment with, a shaft 39 by means of supporting brackets 41. The shaft 39 is rotatably mounted in the side walls 43- of the feeder unit 11.

Referring now particularly to Figure 5, a crank arm 45 is rigidly fixed, at one end, to one end of the shaft 39 and carries a cam follower 46 at its other end. A cam 47 is mounted for oscillatory movement on the side wall 43 and engages the follower 46. The cam 47 is oscillated through linkage members 49, 51 and 53 by a crank arm 55 fixed to a shaft 57. A pulley 59 is fixed to the other end of the shaft 57. A pulley 61 is mounted on a reduction unit 63 driven by a motor 65. Pulleys 61 and 59 are coupled by a belt 67 so that the cam 47 is oscillated continuously by the motor 65. This results in a continuous oscillation of the shaft 39 and provides continuous rocking of the shaft 37 which carries the pick-up fingers 35. The tips of the pick-up fingers are then rocked from a lower rearward position, contiguous to the top sheet 13 of the feeder stack, to an upper forward position where the sheet is fed between a drive roller 68 and pressure roller '69 of the feeder mechanism to be carried to the conveyor track.

Vacuum is provided at the fingers 35 by a vacuum pump 71 driven by a motor 73. The vacuum system' includes two vacuum relief valves in series, each of which,

when actuated, takes vacuum away from the fingers 35.

One of these vacuum relief valves (not shown) is actuated by the sheet pick-up mechanism. As the pick-up fingers 35 are oscillated, the vacuum is shut off at the instant the sheet is fed to the rollers 68 and '69. Vacuum is not again applied to the fingers until the fingers return to their rearward position to pick up the next sheet from the stack. The function of the second vacuum relief valve will be described subsequently in conjunction with the control circuit of the machine.

The conveyor track is defined by side walls 77 and 79 7 and a horizontal bed formed between the side walls. The horizontal bed is comprised of segments provided by the gates 19, fixed plates 81, and drive rollers 15. The drive rollers are rotatably mounted in the side 'walls 77 and 79, respectively, so that the upper surfaces of the drive rollers extend slightly above the plane defined by the gates 19 and the plates 81. A pair of pressure rollers or wheels 17 are associated with each drive roller 15 and are positioned vertically above the drive rollers. The pressure rollers 17 are rotatably mounted on shafts 83 which are secured, at their ends, in brackets 85. The brackets 85 are pivotally mounted on the track side walls 77 and 79 and are biased by means of springs 87 to provide downward pressure of the pressure rollers against the drive rollers. The sets of drive rollers and pressure rollers are spaced sufliciently close together along the conveyor track to provide continuous conveying of the smallest sheet which the machine will be called upon to handle. All of the drive rollers are driven in the same direction. Each of the drive rollers 15 is rigidly mounted on a shaft which extends through the track side wall 77. A pulley '89 for a toothed drive belt is fixed to each of these shafts. Each pulley 89 accommodates two toothed drive belts 91 lying side by side. A drive belt 91 is provided between each two adjacent pulleys 89 and these belts appear staggered when viewed from the top of the machine.

" The shaft for the drive roller 15a, which is adjacent to the feeder mechanism, includes, in addition to a pulley 89, a V-belt pulley 93 and a pulley 95. Two drive rollers 68 and 70, which are associated with the feeder mechanism 11, are rigidly mounted on shafts on which are mounted pulleys 96. The pulleys 95 and 96 are connected by a belt 97 so that the feeder drive rollers 68 and 70 are driven through the shaft of the drive roller 1511. Power is provided to all of the drive rollers 15, 68 and 70 by the motor 73 through V-belt pulleys 93, 99, 101 and 103 and connecting V-belts 105 and 107. The pulleys 99 and 101 are rigidly mounted on a common shaft.

, A row of double tiered sheet receiving bins 23 is mounted on the machine frame beneath the conveyor track. The bins are inclined with respect to the vertical, and each bin comprises a receiving chamber and a member defining an overhang at the upper end of the chamber to facilitate stacking of the sheets in each chamber. The bin chambers may be provided with removable false bottom inserts to facilitate the stacking of smaller sheets in the chambers. Each receiving bin has an entrance channel immediately beneath the conveyor track. Entrance channels 115 for the bins in the lower tier, which are the odd numbered bins in the sequence of operation, are provided between the bins in the upper tier, which are the even numbered bins in the sequence of operation. Entrance channels 117, for the upper tier of bins, are provided between the bin walls and the upper surfaces of deflection plates 119. The overhang for a bin in the lower tier is provided by the receiving chamber immediately above it in the upper tier. The overhang for a bin in the upper tier is provided by a deflection plate 119. See, particularly, Figures 2, 3 and 4.

One gate 19 and one shutter 21 are provided for each set of bins. A set of bins comprises two bins located one above the other. A gate 19, which is a part of the conveyor track bed, is associated with each set of bins and a shutter 21 is positioned between the channels 115 and 117 of each bin set to direct the sheets into one or the other of the channels.

Each of the gates 19 and shutters 21 are fixed to shafts which are rotatably supported in the side walls 77 and 79 of the conveyor track and each is controlled by a rotary solenoid 121 mounted on the side wall 79. The operating sequence of the gates and shutters will be 1 '4 described, subsequently, in conjunction with the control circuit operation.

An overflow bin 25 is provided at the end of the conveyor track opposite from the feeder mechanism. The overflow bin is provided to receive sheets which have been loaded on the feeder and which are in excess of the sheets selected to be directed to the bins 23. A deflector plate 27 directs the sheets from the conveyor track to the bin 25 and a strip spring 29 holds the sheets in the bin.

, A double feed bin 127 is mounted with the bins 23 and is disposed nearest the feeding mechanism 11. A gate 129, similar to the gates 19, is positioned to direct sheets into the bin 127. A switch 131, which is sensitive to sheet thickness, is positioned ahead of the gate 129 and bears against the drive roller 70. This switch is adjusted to detect the passage of more than a single sheet. When'this is detected, the gate 129 is opened, by electromagnetic means, to direct these sheets into the double feed bin 127.

A gating switch 135 is mounted on the conveyor track adjacent the feeder mechanism and bears against the drive roller 15a. This switch is actuated by each sheet 13, and therefore senses each sheet, as it passes from the feeder mechanism to the conveyor track. Its function will be described in connection with the control circuit operation.

A photocell 137 and an associated exciter lamp 139 are mounted on the conveyor track between the feeder mechanism and the first gate 19. A second photocell 141 and associated exciter lamp 143 are mounted on the conveyor track between the last gate 19 and overflow bin 25. Both of the photocells are part of the operating circuit and are actuated in response to index sheets or mats which are stacked with the sheets '13 and which are relatively opaque with respect to the sheets 13 which are assembled.

The operation of the machine will now be described in conjunction with the description of the operating circuit shown in Figure 6 of the accompanying drawing. The sheets to be assembled comprise a plurality of groups of sheets which are stacked one on top of the other and each separated by an index mat. For the purpose of the following description it is assumed that eleven books of twenty pages each are to be assembled. The sheets are stacked in the feeder, then, in the following manner: A group of eleven or more of page 1, an index mat, a group of eleven or more of page 2, an index mat, a group of eleven or more of page 3, and so on until twenty'groups are stacked on the feeder table 31. No index mat is placed on the top of the stack. The feeder is then adjusted (by means not shown) to position the top of the stack adjacent the pick-up fingers 35 and the machine is ready to be operated.

In order to set up the machine to assemble the eleven books, two rotary selector switches and 157 are provided. These switches are conventional. The tens are selected by the switch 155, and the units are selected by the switch 157. In the drawing, these switches are shown as being set to select eleven books. By means of these selector switches, which are mounted on a control panel, any number of books up to sixteen, which is the capacity of the described machine, may be selected.

A rotary step switch 159 comprises four banks of contacts A, B, C and D and a wiper arm associated with each bank. All of the wiper arms are stepped simultaneously, being actuated by the solenoid of a relay 161. At the beginning of operation, the step switch is set in its home position, by means to be described. In the home position of the step switch, each of the wiper arms engages its associated contact No. 1.

For the purpose of describing the operating sequence of the machine, the bins 23 will be referred to as bins 23-1 through 23-16 to indicate the sequence in which the bins receive sheets 13, bin 23-1 being nearest the double feed bin 127, The bins are numbered sue- 1 p 231cm? eessively in alternate tiers. The contacts of the several banks A, B, C and D of the step switch 159 will be refe'rred to as Nos. 1 through 17 to indicate the sequence in which they are engaged by the wiper arms. The gates 19 will be referred to as 19-1 through 19-8, in accordance with their operating sequence, beginning with the gate nearest the gating switch 135. The shutters 21, similarly, will be referred to as 21-1 through 21-8.

The rotary solenoids 121, which operate the gates 19, are connected between the contacts of bank B of the step switch and a common ground. The solenoid for the gate 19-1 is connected to contacts Nos. 1 and 2 of the bank B so that gate No. l is opened through either of these two contacts. Similarly the solenoid for gate 19-2 is connected to contacts Nos. 3 and 4, and so on. The rotary solenoids 121' for the shutters 21 are connected between the contacts of bank C of the step switch and a common ground. These solenoids are connected only to the even numbered contacts since the shutters are actuated to deflect the sheets only into the even numbered bins. The contacts of bank D of the step switch are connected to a common ground through the gating switch 135.

To start the machine, a master switch 145 is closed. This connects standard line voltage (A.C.) to the machine and provides A.C. for the exciter lamps 139 and 143, and for a power supply 147 which provides various voltages (D.C.) for the operating circuit. A start switch 148 is closed to start operation of the machine. This switch is normally open and provides A.C., momentarily, to pull a relay 149. The relay 149 energizes the motor 65 through it's contacts A and the motor 73 through its contacts B. As previously described, the motor 65 drives the feeder and the motor 73 drives the conveyor and the vacuum pump 71. The relay 149 is self-holding through its contact C which is in series with a pair of stop switches 151. The stop switches may be positio'ned at desired locations on the machine and are normally closed. When either of the stop switches is moment'arily opened, the relay 149 is released and the motors 65 and 73 are de-energized to stop operation of the machine. The master switch 145, the start switch 148, and one of the stop switches 151 may be mounted on a control panel.

The pick-up fingers 35 are now operating to transfer individual sheets 13 from the stack to the conveyor track, and vacuum is now applied to the fingers to cause them to pick up the sheets.

When the first sheet 13 passes from the feeder to the conveyor, the gating switch 135 is closed momentarily. A DC. circuit is now complete to pull a relay 163 through a time delay circuit 165 and the bank D of the step switch. When the relay 163 is pulled, it is selfholding through its contact A. DC. is applied to the solenoid of gate 19-1 through a relay 167, the contact C of the relay 163 and contact No. 1 of the step switch bank B. Gate 19-1 is now opened to direct the first sheet to bin 23-1. This condition is illustrated in Figure 3 of the drawing. Simultaneously DC. is applied through the relay 167, and contact B of the relay 163, to pull the relay 161 which actuates the step switch. The step switch is not stepped at this instant, however, since the pulling of relay 1'61 merely cocks the stepping mechanism. When the relay 161 is released, the step switch is stepped so that each of the wiper arms advances to its respective No. 2 contact.

The relay 163 is held, by means of the time delay circuit 165, for a period of time suflicient to permit the sheet 13 to travel from the gating switch to gate 19-1 which is now open, and to be directed into the bin 23-1. It may be assumed that the feeder mechanism feeds the sheets to the conveyor at the rate of one sheet per second, and that the conveyor carries the sheets at a rate suiticient to deliver a sheet to the last gate and shutter within second. Hence, any sheet will be delivered'to any gate and shutter within W1 second. The time delay circuit holds the relay 163, then, for $5 second, leaving second between the releasing of relay 163 and the closing of the gating switch by the second sheet 13.

When the relay 163 is released, DC. is taken away from the relay 161 at the contact B of relay 163, and the relay 161 is released, causing the step switch to advance to the next position, position No. 2.

When the second sheet closes the gating switch 135, the cycle above described is repeated. In this second cycle, the solenoid for the gate 19-1 is energized through contact No. 2 of bank B and this gate is again opened. Simultaneously the solenoid for the shutter 21-1 is energized through the contact C of the relay 163 and the contact No. 2 of bank C. Since both the gate 19-1 and the shutter 21-1 are now open, the second sheet is directed into the bin 23-2 as illustrated in Figure 4 of the draw mg.

This cycle repeats itself until one sheet has been deposited in each bin, up to and including the bin 23-11, which is the last bin to be filled as determined by the selector switch setting. After a sheet has passed into the bin 23-11, the step switch is advanced, as above described, to position No. 12 wherein the wiper arms engage contacts No. 12 of the step switch banks. This position of the step switch is illustrated in Figure 6. The circuit for the relay 167 is now completed through the selector switches and 1-57, and the bank A of the step switch. The relay 167 is now pulled and this takes D.C. away from the contacts B, C and D of the relay 163.

As previously indicated, there may have been more than eleven sheets of the first group stacked in the feeder. These excess sheets continue to be fed to the conveyor and each actuates the gating switch 135 to pull the relay 163. However, since the relay 167 is pulled, no gates or shutters are actuated and these sheets are carried along the conveyor track to the overflow bin 25. The step switch 159 is not caused to advance by these excess sheets since the circuit for the relay 161 is open at the relay 167.

After the excess sheets of the first, group have been fed to the conveyor, the first index mat is fed to the conveyor and is sensed by the first photocell 137. When the photocell 137 is energized, one section of the double triode 169 becomes conducting, momentarily, and this completes a circuit to pull a relay 171. The relay 171 is self-holding through its contact A and the contact C of a relay 173. A circuit for a solenoid 17 5, which actuates a bypass valve 177 in the vacuum line to take the vacuum away from the pick-up fingers 35, is completed through contact B of the relay 171. Now, although the feeder mechanism continues to operate, no sheets are picked up by the pick-up fingers. In the meantime, the index mat is carried along the conveyor track and is sensed by the second photocell 141 just prior to its being deposited in the overflow bin 25.

When the second photocell 141 is energized, the second section of the double triode 169 becomes conducting, momentarily, and a circuit is completed to pull a relay 179. When the relay 179 is pulled, a circuit is completed to pull the relay 173 which is the homing relay. The holding circuit for the relay 171 is now broken at the contact C of the relay 173 and the relay 171 is released. The circuit for the vacuum bypass valve solenoid is now opened at the contact B of the relay 171; however a new circuit has been completed through the contact A of the relay 173 so that vacuum continues to be withheld from the pick-up fingers 35. The relay 173 is self-holding through its contact B and a switch 181 controlled by a cam 183. The earn 183 is a part of the step switch mechanism and is rotated with the step switch. The switch 181 is normally closed, held by a spring 185, and is opened by the cam only when the step switch is in the home position.

Simultaneously with the pulling of the relay 173 again pulled through its contact.

,through the relay 179, a circuit is completed to pull the .relay 161 through its own contact. After the relay 179 is released, this circuit is also maintained through the contact B of the relay 173 and the switch 181. As soon as the relay 161 is pulled, its energizing circuit is broken at its own contact and it is immediately released to ad- Vance the step switch. Upon release, the relay 161 is This intermittent operation of the relay 161 continues until the step switch has been returned to the home position. The contacts of the step switch banks are in a circular array so that the step switch arms may be rotated through 360.

' .When the step switch has returned to its home position, the switch 181 is opened by the cam 183 and this opens the holding circuit for the relay 173, causing the relay to release. The circuit for the solenoid of the relay 161 is immediately opened so that the step switch 'is not advanced beyond the home position. At the same time, thecircuit for the vacuum bypass valve solenoid '175 is open so that vacuum is again applied to the pick-up fingers 35 and the pick-up fingers begin feeding the secbnd group of sheets to the conveyor track. The second group of sheets are then distributed to the several bins 'in the same manner as the first group.

An automatic reset switch 191 is provided. This switch is mounted on the control panel and, when closed, provides DC. to the homing relay 173 to start the homing cycle, as above described, in the same manner that it was started by the relay 179. This switch may be used at any time to advance the step switch to its home position, particularly at the beginning of machine operation.

A manual reset switch 193, also mounted on the control panel, provides DC. to the solenoid of the relay 161 in the same manner that it is applied by the relay 163 to advance the step switch one position. A uni-directional conducting device, such as a diode 195, is placed in the circuit between the solenoid of the relay 173 and the contact of the relay 161. This diode 195 prevents the homing relay 173 from being pulled through the contact of the relay 161, either when the manual reset switch 193 is closed or when the relay 163 is pulled in the normal operating cycle.

It is seen, then, that one of each group of sheets 13 is deposited in each of the eleven bins, the excess sheets of the group being deposited in the overflow bin 25. After each group has been fed to the conveyor track, the index mat stops the feed of the sheets to the conveyor and re-cyclcs the step switch to the home position. At this time the feeding of the second group of sheets to the conveyor track begins. In thismanner eleven books or sets of sheets are assembled completely automatically.

A feature of the machine is a fail-safe provision. In the event that an 'insufficient number of sheets of one group are placed in the feeder stack, the machine will automatically stop functioning. Assume, for example, that only eight sheets of the second group are in the feeder. This means that the index mat will be fed to the conveyor as the ninth sheet of the group. When the index mat is sensed by the first photocell 137, the feed of the following sheets is suspended as previously described. In the meantime, the gate 19-5 has been opened since the gating switch 135 sees the index mat simply as another sheet. The index mat, therefore, is deposited in the bin 23-9 and the machine remains in this condition, until attended to by the operator, since the photocell 141 is not energized. The machine, therefore, cannot assemble sets or books which do not have a complete set of pages.

While the machine has been described and illustrated as having only 16 bins, and therefore can assemble only 16 books or sets of sheets, it will be apparent that additional bins may be provided merely by increasing the length of the machine, for example. The bins may be divided into operating groups of 16, for example, each group being controlled by an individual gating switch.

8 By this means, the operating speed of the machine need not be diminished due to its increased length. i

A machine, constructed in accordance with the invention, having fifty bins is small enough to be mounted on casters for ready portability.

What is claimed is: v

1. In a sheet distributing machine, a plurality of sheet receiving bins, a conveyor track comprising a plurality of gates for directing sheets to said bins, means for feeding individual substantially translucent sheets from a stack including opaque index sheets to said conveyor. track, individual electromagnetic means for operating each of said gates, a control circuit including a cyclic sequencing means for energizing said electromagnetic means, means for selecting the number of'said electromagnetic means to be energized in each cycle of said switch means, sensing means responsive to the passage of one of said sheets along said conveyor track for actuating said sequencing means, said selecting means interrupt; ing the operation of said sequencing means when a preselected number of electromagnetic means have been energized, photoelectric sensing means positioned at one end of said conveyor track responsive to the passage of one of said opaque index sheets for stopping the operation of said feeding means, a second photoelectric sensing means positioned'at the other end of said conveyor track responsive to one of said opaque index sheets for re-cycling said sequencing means and for re-starting the operation of said feeding means.

2. A machine for assembling stacked groups of sub.- stantially translucent sheets into sets of sheets, said groups of sheets being separated by opaque index sheets, said machine comprising a conveyor track including a plurality of gates normally defining a flat surface over which said sheets are carried, support means for a stack of sheets disposed at one end of said conveyor track, means for carrying said sheets along said conveyor track, a plurality of sheet receiving bins disposed beneath said track each associated with a gate, a cyclic control means for actuating said gates individually and sequentially to direct said sheets into successive'bins, means associated with said gate control means for selecting the number of gates to be actuated thereby in each cycle, feed means for removing individual sheets from a stack on said support means and introducing them to said conveyor track, an overflow bin disposed at the other end of said conveyor track for receiving excess sheets, switch means positioned at said one end of said conveyor track responsive to the passage of one of said sheets for actuating said gate control means, photoelectric sensing means positioned at said one end of said conveyor track responsive to the passage of one of said opaque index sheets for stopping the operation of said feed means, and a second photoelectric sensing means positioned at said other end of said conveyor track responsive to the passage of one of said opaque index sheets for re-cycling said gate control means and for re-starting said feed means.

3. A machine for assembling stacked groups of substantially translucent sheets into sets of sheets, said groups of sheets being separated by opaque index sheets, said machine comprising a conveyor track including a plurality of gates normally defining a flat surface over which said sheets are carried, support. means for a stack of sheets disposed at one end of the conveyor track, means for carrying said sheets along said conveyor track, a plurality of sheet receiving bins disposed beneath said track each associated with a gate, a cyclic control means for actuating said gates individually and sequentially to direct said sheets into said bins, means associated with said gate control means for pre-selecting the number of gates to be actuated thereby in each cycle, feed means including a vacuum pick-up for removing individual sheets from said stack and introducing them to said conveyor track, switch means positioned at the feed end of said conveyor track responsive to the passage of one of said sheets for actuating said gate control means, a photoelectric sensing means positioned at the feed end of said conveyor track responsive to the passage of one of said index sheets for removing vacuum from said feed means, and a second photoelectric sensing means positioned at the other end of said conveyor track responsive to the passage of one of said index sheets for re-cycling said gate control means and for re-applying vacuum to said feed means.

References Cited in the file of this patent UNITED STATES PATENTS Truitt et a1 May 6, 1941 Williams Oct. 27, 1942 Little Dec. 27, 1949 Ghertman Jan. 20, 1951 McGalliard Dec. 1, 1953

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