US3708055A

US3708055A - Dispensing method and apparatus

Info

Publication number: US3708055A
Application number: US00157347A
Authority: US
Inventors: R Miller; D Neill
Original assignee: Kraft Inc
Current assignee: Kraft Inc
Priority date: 1971-06-28
Filing date: 1971-06-28
Publication date: 1973-01-02
Anticipated expiration: 1990-01-02
Also published as: CA956659A; AU471208B2; DE2229867A1; GB1365223A; AU4273472A

Abstract

Method and apparatus for depositing articles at uniformly spaced positions on a conveyor in such a manner as to maintain a predetermined flow of the articles on the conveyor from at least two dispensers arranged in tandem adjacent the conveyor.

Description

[451 Jan. 2, 1973 United States Patent [191' Miller et al.

l/l954 Meulemans......;.........................

Primary Examinerf-Richard E. Aegerter Attorney-Fitch, Even, Tabin & Luedeka M. Neill, Chicago, both of Ill. [73] Assignee: Kraftco Corporation, Chicago, ll]. 22} Filed:

June 28, 1971 Method and apparatus for depositing articles at uniformly spaced positions on a conveyor in such a Appl. No.: 157,347

manner as to maintain a predetermined flow of the articles on the conveyor from at least two di ranged in tandem adjacent the conveyor.

spensers ar- [52] U.S. 198/56 [51.] Int. Cl. 47/26, 865g 47/18 [58] Field of Search .....31/5; 53/59; 221/10, 14, 110;

6 Claims, 7 Drawing Figures [56] References Cited UNITED STATES PATENTS "2 1935 Hobleck.....

PATENTED A 2 975 3. 708 055 SHEET 1 OF 5 PATENTEDJAN 2197s 3,708,055

SHEEIEUFS INVENTORS ROLAND E. MILLER DAVID M. NEILL ATTYS.

PATENTEDJAK 2:915

SHEET 3' [IF 5 PATENTEU JAN 2 I973 SHEET 4 0F 5 FLOW SEQUENCE CONTROL FIG? LER

DISPENSING METHOD AND APPARATUS This invention relates generally to the depositing of articles on a conveyor. More particularly, it relates to a method and apparatus for the automatic operation of a plurality of article dispensers arranged in tandem adjacent a conveyor to produce an uninterrupted flow of uniformly spaced articles on the conveyor.

When dispensing articles onto a moving conveyor, there often is a need downstream of the article dispenser for repeatability and reliability of positioning of thearticleson the conveyor. In the situations where this need is present and the article dispenser has a limited capacity, a second dispenser may be provided to deposit articles on the conveyor while the first dispenser is idle having its supply replenished to stand by in readiness until the second dispenser exhausts its supply. If the two dispensers could be opposite one another and be so located that the position on the conveyor of the discharge of one is in registry with the position on the conveyor of the discharge of the other, there is little difficulty in coordinating the two dispensers to provide continuity on the conveyor. Because of structural factors,such disposition of the dispensers opposite each other is often not practical or possible. If the dispensers are disposed in tandem along the conveyor a given distance apart, a difficulty is then presented in coordinating the control of the two dispensers to prevent unwanted gaps in the positioning of the articles on the conveyor and unwanted overlapping of articles on the conveyor. The method and apparatus of the present invention provide a convenient and reliable solution to this problem.

One example of moving articles on a conveyor from a dispenser having a limited capacity is a slicing machine for cutting slices from a food material, such as cheese, which are subsequently individually wrapped at a work station downstream of the slicer.

Various commercial slicing machines are available for intermittently slicing bars of cheese to obtain stacks of a predetermined number of slices for packaging. These machines may include a counter operatively connected to a slice accumulator to transfer a stack of a predetermined number of slices to a scale for weighing and subsequent packaging. Normally, provision is made for the counter to periodically initiate a pause in the slicing to permit stack removal, weighing and the like. Machine operation is also interrupted at a time when the capacity of the machine is replenished or recharged. Such machines, intended primarily for producing stacks of slices in preparation for packaging, are not useful for producing slices in a system which includes provisions for individually wrapping each slice and subsequently packaging an accumulation of these individually wrapped slices.

Heretofore the preparation and packaging of individually wrapped cheese slices has been relatively slow, and consequently resulted in high production costs. One way of reducing these high costs is to provide a system capable of automatically slicing, individually wrapping, and group packaging the individually wrapped slices in high volume. Such a system requires, among other things, a rapid slicer to produce a large number of slices per unit of time. A rapid slicing machine suitable for this is shown and described in copending'application Ser. No. 146,286'filed May 24,1971. This machine can produce as many as 200 slices per minute. The details of the machine are set forth in that application and, other than the details believed to be helpful in understanding the present invention, will not be repeated herein.

Even a single high speed slicing machine can not provide slices continuously over an extended period of time, since it has limited capacity and periodically must become idle to reload the machine, i.e., to replenish the material being sliced after the effective supply contained by the machine is exhausted. It is therefore desirable to provide a plurality of slicing machines to discharge slices onto a conveyor and to control the machines in such a manner that the slices are uniformly spaced and aligned on the conveyor, without gaps or overlaps as they are infed to a work station downstream of the slicing machines. A wrapping machine to rapidly handle individual slices is an example of a downstream work station that requires repeatability and reliability of positioning of the slices infed to it. With a plurality of slicers, one machine can have its supply replenished and then be held in readiness while another machine is depositing slices onto the conveyor until its effective supply is exhausted. Thus, downtime for reloading a given machine need not interrupt the flow of slices to the downstream work station. To avoid relying on an operator to timely transfer the slicing operation to a machine standing in readiness, it is desirable to provide the system with a means for automatically controlling the sequence of operation of the machines. The controlling becomes complicated when the structure of the slicing machines requires them to be disposed in tandem along the conveyor line rather than opposite one another on the line.

When in tandem along a conveyor moving in a given direction, one machine is downstream of another, and a different timing problem exists when transferring the slicing operation from the downstream machine to an upstream machine from that existing when transferring the slicing operation from the upstream machine to the downstream machine. To illustrate, when the upstream machine is depositing slices onto the conveyor and its effective supply becomes exhausted, the idled downstream machine standing in readiness must not begin depositing slices until the first vacant slice position immediately following the last slice deposited by the upstream machine comes into registry with a discharge path of the downstream machine to accept the first slice to be deposited by that machine. On the other hand, when the downstream machine is depositing slices onto the conveyor and its effective supply becomes exhausted, the idled upstream machine standing in readiness must begin depositing slices prior to the downstream machines being idled so that the slice positions between the discharge paths of the two machines are filled with slices.

Accordingly, it is a primary object of the present invention to provide a method and apparatus for the automatic control of aplurality of dispensers in tandem on a conveyor line.

It is a further object of the invention to provide a method and apparatus for transferring the slicing operation from any one slicing machine of a plurality of slicing machines in tandem on a conveyor line to another without interrupting a continuous flow of slices and a predetermined orientation and spacing within the flowof slices on the conveyor at the time of transfer.

These and other objects of the present invention are more particularly set forth in the following detailed description and in the accompanying drawings of which:

FIG. 1 is a perspective view of two slicing machines arranged in tandem along a conveyor line with an electrical control schematically illustrated that sequences the machines in accordance with one embodiment of the present invention;

FIG. 2 is a fragmentary side view of one of the slicing machines of FIG. 1;

FIG. 3 is an enlarged perspective view of a portion of the slicing machines of FIG. 2 with an exploded view of a portion thereof illustrating a hold on assembly to hold down a bar of material during slicing of the material FIG. 4 is an enlarged perspective view of a portion of FIG. 2 illustrating a reject tray assembly;

FIG. 5 is a block diagram illustrating the interrelation of the electrical parts of one embodiment of the invention;

FIG. 6 is a front view of a vacuum head which engages the rear end or heel of a bar of material to be sliced; and

FIG. 7 is a block diagram illustrating job spaces on the conveyor and their relation to the slicing machines of FIG. 1.

To simplify the description herein, the plurality of slicing machines mentionedearlier will be limited to two machines. Hence, the preferred embodiment of the present invention sets forth two slicing machines in tandem on a conveyor line. The slicing machine downstream of the other is referred to herein as the downstream machine, and the other machine is referred to as the upstream machine. These references upstream and downstream are derived from the relative positions of the machines along the conveyor with respect to the direction of flow of slices thereon.

Broadly, the preferred embodiment of the present invention provides a method and apparatus to control the sequence of operation of two limited capacity slicing machines, arranged in tandem on a conveyor line, so that any one machine deposits slices on the conveyor until its effective supply of material is exhausted while the other machine stands by in readiness to deposit slices in time to maintain a continuity of flow of slices on the conveyor line when the depositing machine is to be idled for having its supply replenished and then standing by in readiness. The machines are controlled to effect a timely transfer of their slicing operations from one to the other irrespective of whether the slicing transfer is in the direction of the slide flow or against it. A rapid production of slices by the slicing machines and a continuity of flow of the slices on the conveyor permit a work station downstream of the slicing machines on the conveyor line to efficiently and continuously perform a subsequent operation upon the slices, such as individually wrapping the slices.

Briefly, as shown in FIG. 1, the system of the present embodiment comprises a downstream slicing machine 11; an upstream slicing machine 13; a conveyor 15, illustrated as a lug conveyor, which accepts slices 16 from both slicing machines and carries the slices in a flow downstream of the machines; and a sequence control 17, which coordinates the slicing operations of the two slicing machines in tandem. In communication with the sequence control 17 is a sensor 19 on the conveyor 15 which senses indicia on the conveyor, for example the lugs 20 of the lug conveyor, thereby enabling the sequence control 17 to establish a count of job spaces or slice positions for the purpose of coordinating the two machines. A work station, such as a wrapper 21, for wrapping cheese slices is shown on the conveyor line downstream of the slicing machines to represent a subsequent operation on the slices. If material other than cheese is being sliced or other articles handled on the conveyor, a different operation downstream may be appropriate.

The slicing machines 11 and 13 are of the type disclosed in copending application Ser. No. 146,286 and differ from each other primarily in their positions relative to one another with respect to the conveyor 15. Initially, both machines are loaded, each with a bar of cheese. To load a slicing machine, a cheese bar 23, shown in phantom, is placed by the operator on an inclined product tray 25, which comprises rollers 27, as best seen in FIG. 3. Initially, the bar is permitted to rest against a product safety stop 29, which in FIG. 3 is illustrated in its raised position for ease of illustration. Normally, this safety stop is maintained in a lower position until the slicing operation is commenced and in such lower position prevents the bar 23 from contacting a rotating blade 31. A hold on assembly 33, which comprises a hold bar 35 urged downwardly by a spring 37, is provided for engagement with the top surface of the bar of cheese to hold it against the lower portion of the inclined product tray 25 during slicing.

As best seen in FIGS. 2 and 6, the heel 39 of the bar of cheese is engaged by a vacuum head assembly 41, the assembly comprising a vacuum head 43, a front screen 45, and a blade 47. The blade 47 is in the form of an oval or closed loop screen 45. When the vacuum head 43 is forced into engagement with the heel 39 of the cheese, a seal is formed within the closed loop of the blade 47. A hose 49 connects the vacuum head 43 to a service source (not shown) for creating a vacuum. After the vacuum is turned on, the vacuum assembly 41 holds the cheese bar during its advancement along a path on the inclined product tray 25 into a position to be cut by the rotating blade 31 and prevents the bar from being pulled into the rotating blade by the cutting action.

A side plate 51 is manually adjustable against one side of the cheese bar to center the bar on the inclined tray 25. A side clamp 53 is movable against the other side of the bar, thus forming a channel with the side plate 51 to restrict the bar in lateral movements during slicing. This side clamp 53 and the product safety stop 29, mentioned earlier, are actuated by pistons, the operation of which will be explained hereinafter.

The vacuum head assembly 41 is attached to and carried by a carriage 55. A yoke-shaped extension arm 57 of the carriage 55 slidably engages a carriage support rod 59. A similar carriage support rod (not shown) is on the opposite side of the machine and parallels the support rod 59 and a carriage feed screw (not shown). The feed screw continuously rotates in a given direction to advance the carriage 55 and the vacuum head assembly 41 thereon toward the rotating blade 31. A suitable means releasably engages the carriage 55 with the feed screw, for example a pair of half nuts, and a feed screw motor 61 provides the motive force forthe feed screw rotation. At the conclusion of slicing the bar 23 the carriage 55 is released, and it is retracted to the opposite and upper end of the inclined tray 25 for reloading with a new bar of cheese. The release occurs as the cheese heel 39 approaches the rotating blade 31 and a tripping mechanism (not shown) causes the carriage to become disengaged from the feed screw. When this occurs, a weight (not shown) channeled within a weight guide 62 retracts the carriage to its upper or reload position through a chain 63 attached to the carriage bar extension 57. Intermediate portions of the chain 63 are engaged and guided by a sprocket 65.

Coordinated with the mechanical release of the carriage at the conclusion of slicing, is the interruption of the control circuit of the feed screw drive motor 61. This interruption is accomplished by a proximity limit switch 67, which may be of a conventional type, actuated by the presence of the carriage bar extension 57. The actuation opens a set of normally closed contacts (not shown) in the proximity limit switch, and the motor 61 is stopped.

As mentioned previously, the hold bar 35 is urged into a position across the top and against the product bar 23 by the spring 37. As the slicing of the product bar progresses and the vacuum hold assembly 41 approaches the rotating blade 31, a plow 69 overhead of the vacuum head 43 and mounted thereon has its forward end pulled downwardly by the urging of a spring 71. The plow is rotatably connected about a'pivot 73, and at its rear is a cam follower 75. When the vacuum head assembly 41 is retracted by the carriage to the upper end of the inclined tray 25, the cam follower 75 is in contact with and rolls along the undersurface of a cam 77. In this position, the plow 69 is lifted from the vacuum head 43 and the heel 39 leaving access for the loading of a new product bar. As the slicing progresses and the vacuum head assembly 41 is advanced toward the rotating blade 31 with the carriage 55, the cam follower 75 eventually clears the lower surface of the cam 77 and no longer restrains rotation of the plow 69 about its pivot 73 by the urging of the spring 71. Consequently, the front edge of the plow 69 is brought to a lower position by the urging of the spring and rests on the heel 39 of the product bar 23. In this position, the plow presents an inclined surface or wedge to the underside of the hold bar 35. The continued advance of this wedge lifts the hold bar from the cheese heel so that the cheese heel can be retracted. The hold on assembly 33 is best seen in FIG. 3. In a fragmentary exploded view the hold on bar 35 and the spring 37 are illustrated. The hold bar 35 is rotatably mounted about pivot points 79 and 80. The hold plate spring 37 has one end connected to a spring adjusting mechanism 81 and the other end connected to an extension 83 of the hold bar 35 The raising of theholdbar from the cheese heel at the conclusion of slicing is adjustable to occur simultaneously with the release of the carriage 55 from the feed screw and the stopping of the feed screw motor 61. As mentioned previously, the proximity limit switch 67 senses the presence of the carriage extension arm 57 and causes the interruption of the control circuit of the feed screw motor 61. In addition, the proximity limit switch at this time effects the release of the side clamp 53 from the side of the heel of the cheese bar. This side clamp release is caused by the activation of a cylinder 85, detailed hereinafter. That which activates the cylinder 85 also starts the timing of an adjustable, resettable timer 87 (FIG. 5), a part of the sequence control 17. After a predetermined period of time, the timer closes a circuit to actuate a product safety stop cylinder 89 to lower the safety stop 29. This predetermined period is a time delay to assure removal of the heel 39 from the path of the blade 31 before the safety stop is lowered.

To completely effect the retraction of the carriage S5 to a load-unload position on the inclined product tray 25, the following steps occur as the heel of the cheese bar approaches the rotating blade: (I) the inclined plow 69 above the vacuum head 43 lifts the holding plate 35 from the heel of the product bar 23; (2) the carriage extension arm 57 trips a mechanism for releasing the carriage from the feed screw; and (3) the proximity limit switch 67 senses the presence of the carriage extension arm 57 and (a) effects the release of the side clamp 53 from the side of the product bar heel, (b) causes an interruption of the control circuit of the feed screw drive motor 6.1 to stop the motor, and (c) starts the timing of the timer 87, which at the conclusion of a predetermined time effects the lowering of the safety stop 29. The carriage 55 is then retracted by the weight hanging at the distal end of the chain 63. During the travel of the carriage in retraction, the cam follower reengages the lower surface of the cam 77 and lifts the plow 69 to an approximately horizontal position. At the conclusion of the carriage retraction, the operator removes the remains of the cheese bar and replaces it with a new bar. Because a heel is left and, as hereinafter described, certain initial slices are rejected, each cheese bar 23 is not completely used in supplying slices. Hence, as generally used herein, the term effective supply indicates slices from a cheese bar less its waste.

As seen in FIG. 2, the cylinders and 89 are each controlled by two solenoid valves. Specifically, the side clamp cylinder 85 is controlled by a side clamp in solenoid valve and a side clamp out solenoid valve 97. The product safety stop cylinder 89 is controlled by a safety up solenoid valve 91 and a safety down solenoid valve 93. A fluid source, such as an air supply (not shown), feeds each valve-cylinder system at an intake 99 on each system. When the safety up solenoid valve 91 is energized, a piston within the cylinder 89 moves downwardly as viewed in FIG. 3. This movement rotates a safety stop shaft and the safety stop 29 through the intermediate connections of a safety stop lever 103 and a piston rod 101. Thus, a downward movement of the rod 101 moves the safety stop 29 upwardly. When the safety down solenoid valve 93 is energized, the rod 101 moves upwardly and the safety stop 29 is moved to its lower position. The side clamp cylinder 85 is disposed horizontally and moves the side clamp 53 alternately toward and away from the side of the cheese bar. The circuit controlling all solenoid valves is described hereinafter in connection with the sequence control 17 and FIG. 5

It has been shown that the product bar 23 is advanced for slicing along a path on the inclinedproduct tray 25 into the path of the rotating blade 31. Desirably, two independent power sources drive the rotating blade 31 as disclosed in copending application Ser. No. 146,286 This blade has both a rotary motion about its own axis and an orbital motion about a separate axis. By causing the blade 31 to follow an orbital path simultaneously with its rotation upon its own axis, it inflicts a slashing out upon the cheese bar rather than a straight slicing cut. Moreover, the speed of rotation of the blade 21 on its own axis is completely independent of the speed of the orbital rotation. A motor 107 through a suitable drive system provides the motive force for the rotating blade 31. A motor 109 through a suitable drive system provides the motive force for the orbital motion of the blade 31. A suitable speed adjusting control 111 (FIG. is used to adjust the output speed of the blade motor 107, and a suitable I speed adjusting control 113 is used to adjust the output speed of the orbiter motor 109.

Because the feed screw rotates continuously, the carriage, when in engagement with the feed screw, advances continuously toward the blade. Consequently, the cheese continues to advance during the cutting strokes of the blade, resulting in a slight skew to each slice. Since the same relative movements occur during each cutting stroke, however, the slices have substantially parallel surfaces and are uniform relative to each other, with the exception of the first few slices of a new cheese bar. The new bar initially has squared surfaces, and the first slices from it are slightly wedge shaped. It is desirable, therefore, to discard the first few slices made from each new product bar in order that all of the slices deposited on the conveyor will be substantially alike. Through experiments it has been found that the slices are acceptable after the first three slices. Accordingly, the slicing machine has a means of counting and automatically discarding these first three slices. This means includes a reject tray assembly 115 (FIGS. 2 and 4) and an adjustable, resettable counter 157 (FIG. 5).

Briefly, after a slice is cut, it is discharged on a path generally indicated by the dashed line 116 in FIG. 2 toward the conveyor 15. The reject tray assembly 115 is positioned intermediate the blade 31 and the conveyor in the path of a falling slice. The reject tray 117 of the assembly has two positions, an extended or reject position, in which the tray intercepts falling slices, and a retracted accept position out of the path of the falling slices. In the accept position, the reject tray is inclined to such an extent that the intercepted slices easily slide off the tray into a waste receptacle. As long as the tray remains in this position out of the path of the falling slices subsequent slices fall freely along their path toward the conveyor 15. When the carriage returns to the load-unload-position, the reject tray is actuated, as detailed hereinafter, to its extended position and remains there in the path of the falling slices to intercept the initial slices from the next cheese bar.

In the-disclosed embodiment, asbest seen in FIG. 4, the reject tray assembly 115 includes a reject tray 117 rotatably mounted at one of its ends to a reject tray frame 119 at pivot points 121 and 123. The frame 119 is slidably mounted in

yokes

125 and 127, which are supported by

brackets

129 and 131 respectively. The tray 117 preferably presents little surface area to the slices so that the slices easily slide off it, and, to this end, comprises a plurality of rods 133 spaced apart from each other and held together by cross members 135 and 137. The cross member 137 supports

cam followers

139 and 141, which serve to guide the nonpivoted end of the tray 117. The cam followers ride in a pair of arcuate cam tracks 143 and 145 respectively. The solid linesof FIG. 4 illustrate the tray 117 and its frame 119 in the extended or reject position, whereas the dashed lines for the tray and the tray frame illustrate the assembly in the retracted or accept position. As can best be seen in FIG. 2, the general orientation of the reject tray assembly 115 is slightly inclined from a horizontal position. The pivoted end of the tray 117 slides in a plane of this orientation. The opposite end of the tray, through the

cam followers

139 and 141 riding inthe cam tracks 143 and 145, is directed downwardly from the plane as the tray frame 119 is retracted. At the fully retracted position, the tray 117 is greatly inclined to the horizontal. This second position of the tray 117 permits the slices caught on the tray to easily slide'off into a receptacle (not shown), which is removably placed below the tray 117 for this purpose.

Movement for the tray and frame assembly is effected by a cylinder 147, having a piston rod 149 connected to a cross member 151 of the tray frame 119. The piston is operated within the cylinder 147 by an air supply (not shown) infed at the air intake 99. A reject solenoid valve 153 and an accept solenoid valve 155 control the actuation of the cylinder 147. When the reject solenoid valve 153 is energized, the valve is opened and pressure increases in the base of the cylinder 147 with which it is in communication. The increasing pressure moves the piston rod 149 outwardly, and the frame connected thereto likewise is moved outwardly into the reject position illustrated in solidline in FIG. 4. When the accept solenoid valve 155 is energized, a buildup of pressure at the rod end of the cylinder 147, causes the piston to retract the rod 149 and the tray frame 119 attached thereto. During retraction of the tray frame the

cam followers

139 and 141 are guided by the cam tracks 143 and 145 respectively in an armate path downwardly, causing the tray to be rotated about the pivot points 121 and 123 into the tilted accept position shown in phantom in FIG. 4. In the accept position, the tray 117 no longer intercepts the path of the falling slices, and further slices fall freely toward the conveyor 15.

Initially, the tray is extended to the reject position and remains there to receive the predetermined number of slices. An adjustable, resettable counter 157 (FIG. 5) provides the signal to actuate the accept solenoid valve 155 for retracting the reject tray to the accept position. This counter is manually adjustable for presetting the number of slices to be rejected. Once the tray 119 is retracted to the accept position it remains in this position until the proximity limit switch 67, hereinbefore described, provides an electrical signal to actuate the reject solenoid valve 153 to extend the tray to its reject position, which is the initial position for the slicing of a new cheese bar. At the conclusion of its preset count, the counter not only sends a signal to the accept solenoid valve, but also resets itself in preparation for the next counting cycle, which occurs at the beginning of the slicing of the next cheese bar.

Although an air system has been used in the preferred embodiment for actuating the side clamp cylinder 85, the product safety stop 89 and the reject stream slicer 13 additionally bear the subscript tray assembly cylinder 147, it is recognized that a hydraulic system or other suitable system could be used for this purpose.

In the preferred embodiment of the present invention, the conveyor 15 is a lug conveyor. An upright lug at regular intervals provides a back stop for the trailing edge of each slice deposited thereon. Therefore, the lugs are spaced according to the size of the slice produced. For example, in the slicing of cheese, the conveyor has job spaces that are on 8% inch centers; and so, as may be seen in FIG. 1, the lugs are centered a distance d apart, which is nominally 8% inches. The sensor 19 senses indicia on the conveyor which are spaced apart a distance equal to the job spaces on the conveyor. When, as illustrated, the conveyor is a lug conveyor, it is convenient to have the indicia be the lugs 20. Thus, the sensor 19 detects the passing of each lug 20 on the conveyor 15 and sends a signal to the resettable counter 157 in the sequence control 17 (FIG. 5). Through this communication, the sequence control 17 is able to correctly time the occurrence of events in the ordered transfer of slicing from either machine in tandem to the other, as is hereinafter detailed.

The electrical sequence control of the mechanical functions of the two slicing machines is the center for regulating the ordered transfer of slicing. As mentioned previously, both machines are initially loaded in preparation for slicing, and automatic operation is initiated by actuating a sequence start switch 159, which preferably is of the momentary pushbutton type. Until a sequence stop switch 161, which also preferably is of the momentary pushbutton type, is actuated all slicing operations are automatically controlled by the sequence control 17.

Broadly, as may be seen in FIG. 5, the sequence control 17 comprises a logic circuit 163, the sequence start switch 159, the sequence stop switch 161, an adjustable, resettable counter 157, and two adjustable,

resettable timers

87 and 87a. Although the present invention is limited to two slicing machines in tandem on one conveyor line for ease of illustrating, it is understood that one skilled in the art using-the principles described herein could expand the system to include control of slicing machines on more than one conveyor line, or control of more than two slicing machines in tandem on a given conveyor line, or both.

. The sequence control 17 includes portions common to both slicing machines, and portionsused only for a single slicing machine. For example, the counter 157 is common to the circuits of both slicing machines, whereas the timer 87 is only in the circuit of the downstream slicer 11. Electrical components of the downstream slicer ll thatare duplicated on the upstream slicer l3 bear the same reference numbers, but aredistinguishable in that these components of the upa, as seen generally in the lower half of FIG. 5.' Thethree phase AC input voltage supplies power to the orbiter motors 109 and 1090, the

blade motors

107 and 107a, and the feed screw drive motors 61 and 61a. Each of these motors has means for adjusting. its output speed. The adjustable speed controls 113 and 113a are apthe adjustable speed controls 111 and 111a are applied plied to the orbiter motors 109 and 1090 respectively; 5

to the

blade motors

107 and 107a respectively; and the adjustable speed controls and 60a are applied to the feed screw drive motors61 and 61a respectively. These adjustable speed controls may be of the conventional type and are controlled manually.

The

orbiter motors

109 and 109a and the blade motrolling the feed screw drive motors on the slicing machines, the sequence control 17 controls six solenoid valves on each slicing machine. These solenoid valves are: the safety up valves 91 and 91a, the safety down

valves

93 and 93a, the reject tray accept valves 155 and 155a, the reject tray reject

valves

153 and 153a, the side clamp in valves 95 and 95a, and the side clamp out valves 97 and 97a. Each slicing machine, through the proximity limit switches 67 an 67a,pro vides signals'received by the logic circuit 163 and thence by the other machine. Signals from the conveyor are provided by the sensor 19.

More particularly, the logic circuit 163 is an electronic circuit comprising well-known circuit com ponents such as transistors, resistors, and capacitors suitably connected to provide information control functions. Portions within the circuit receive voltage inputs corresponding to binary levels and furnish voltage outputs coded to correspond to logical operations. The circuit will not be detailed herein since it comprises logic function modules or elements that are both available in standard forms from commercial sources and readily usable by one skilled in the art. One example of a standard form and a commercial source for it is the NORPAK solid statelogic control, manufactured by Square D Go, Milwaukee, Wis. Alternately, these control functions could be accomplished by the, application of conventional relay circuitry.

As mentioned previously, a difficulty is encountered in maintaining a continuity of flow of slices on a conveyor when the slices are fed alternately from a plurality of slicing machines in tandem along the conveyor line, because of the limited capacity of the slicing machines. One machine deposits slices while another one stands by inreadiness to commence depositing when the first one runs out of material and needs to have its supply replenished. Without more, merely transferring the slicing operation from a downstream machine when its supply is exhausted to a upstream machine would result in a gap in the flow of slices; and from an upstream machinewhen its supply is exhausted to a downstream machine, an overlap of slices. Neither a gap nor an overlap is desirable for a subsequent operation rapidly performed on the slices downstream of the slicing machines. The present invention resolves the difficulty by coordinating .the operative steps of each machine during transfer of the slicing operation from one machine to the other machine.

Referring now to FIG. 7, by block diagram a relationship is shown between the downstream slicer 11, the upstream slicer 13, and the conveyor 15. The figure further illustrates job spaces 22 on the conveyor, and for ease of illustration, these job spaces are shown occupying equivalent stationary positions labeled A through K on the conveyor. In this Figure, the discharge paths 116 of the slices from each machine are illustrated by solid lined arrows. The position J is shown in registry with the slice discharge path 116 of the downstream slicer 11, and the position B is shown in registry with the slice discharge path 116 of the upstream slicer 13. The two machines are spaced apart along the conveyor a distance dd equal to eight full job spaces. Although the positions illustrated are stationary as indicated in FIG. 7, in actual operation there is a flow of the job spaces in the direction indicated by the arrow on the conveyor 15. A lug 20 (FIG. 1) at the trailing edge of each job space moves with the conveyor. The sensor 19 detects the passing lugs and provides a signal that is received by the counter 157 (FIG. 5) of the sequence control 17. Thereby, a count of the job spaces passing the sensor, and consequently passing each slicing machine is obtained.

Certain general conditions exist in the embodiment of the present invention. If either the downstream slicing machine 11 or the upstream slicing machine 13 is manually stopped during operation by actuating the sequence stop switch 161 the following occurs on both: the

reject solenoid valves

153 and 153a are energized and the accept solenoid valves 155 and 155a are deenergized; the feed screw drive motors 61 and 61a are stopped; and the counter 157 is reset and its input is disabled. Upon either the initial starting of the slicers or the restarting of the slicers after a shutdown, the actuation of the sequence start switch 159 sequences the downstream machine first. A suitable means (not shown) is provided for adjusting the speed of the conveyor, and, hence of the flow of job spaces passed the slicing machine to conform the conveyor speed to the slice production speed of the machines. Otherwise, the speed of the conveyor is constant and its movement is in a given direction. Even though the speeds are conformed, the machines may not be synchronized with the conveyor. By instantaneous speed adjustments of each of the orbiter motors, as, for example, by phase shifting synchronous motors, each slicing machine can be synchronized with the conveyor so that a slice on either machine is discharged at a time when a job space on the conveyor is in register with the slice discharge path of the machine. Since the counting of passing job spaces on the conveyor is directly related to the number of slicing cycles of the machines and, hence, to the number of cuts or slices produced by the machines, there is a correlation between a given count obtained on the counter and the number of slices cut, although not necessarily deposited on the conveyor as hereinafter is seen.

At initial start up, power is applied to all equipment. When the power is applied, but prior to actuating the sequence start switch 159, the safety stop down

solenoid valves

93 and 93a and the

reject solenoid valves

153 and 153a are energized. Thus, initially the product safety stops 29 on both machines are down, and the reject trays 117 on both machines are extended in readiness to intercept the first few slices. After each machine is loaded in the manner previously described, each of the vacuum interlock switches 165 and 165a is actuated. Each switch actuation provides a signal which actuates the vacuum system (not shown) of each machine and which energizes each of the side clamp in solenoid valves and 95a. Other than on initial start up, the vacuum system is not a part of the control sequence. It is understood that signal as used herein may include either the presence or absence of voltage or current and may involve circuit elements intermediate the object providing the signal and the object acted upon as a result of the signal. In other words, the final energizing voltages or currents may be controlled directly or indirectly by logic or control voltage or changes in levels thereof.

The sequence start switch 159 is then actuated to start the slicing operation and the downstream slicing machine 11 is put into operation first. Actuating the sequence start switch 159 provides a signal in the logic circuit 163 that energizes the downstream safety stop up solenoid valve 91 and deenergizes the downstream safety stop down solenoid valve 93, enables the input of the counter 157 of the sequence control 17, and starts the downstream feed screw drive motor 61. Immediately, the feed screw begins advancing the cheese bar into the rotating blade 31 (FIG. 3). After cutting three slices, the counter provides a signal that resets the counter, disables the counter input, energizes the downstream accept solenoid valve and deenergizes the downstream reject solenoid valve 153. Consequently, the reject tray 117 is retracted, and the first three slices caught thereon slide off into a separate receptacle. As the slicing operation of the downstream machine continues, the further slices discharged are accepted by being deposited onto the conveyor 15. Meanwhile, the upstream machine 13 is idle, but is maintained in readiness by its connection to the logic circuit 163 to receive an actuating signal from the downstream machine as its supply becomes exhausted.

As the heel 39 (FIG. 3) of the cheese bar approaches the rotating blade 31 of the downstream machine, the proximity limit switch 67 detects the approach of the carriage extension arm 57 and provides a signal that enables the input of the counter 157, energizes the upstream safety up solenoid valve 91a and deenergizes the upstream safety down solenoid valve 93a, and starts the upstream feed screw drive motor 610. Thus, the feed screw of the upstream slicing machine 13 begins advancing the cheese bar into the rotating blade for slicing. After three slices have been cut, the counter 157 provides a signal that resets the counter, energizes the upstream accept solenoid valve 155a and deenergizes the upstream reject solenoid valve 153a. Thus, the reject tray 117 of the upstream slicing machine is retracted to separately deposit the first three slices of that machine and to permit acceptance of further slices. It will be noted that both slicing machines are cutting slices simultaneously at this point inasmuch as no signal yet has been provided to stop the downstream feed screw drive motor 61 and cause the downstream machine to cease depositing slices. Simultaneous cutting is necessary, of course, to permit the first three slices to be cut and retracted on the upstream machine before accepted slices are deposited by it while the downstream slicer is still depositing slices.

Further, it may be seen by examining FIG. 7 that even after the first accepted slice is produced by the upstream machine, it is deposited onto the conveyor at position B, whereas the downstream slicing machine 11 deposits slices onto the conveyor at position J. There fore, if the downstream slicing machine 11 were to cease depositing slices immediately after the discharging of the first accepted slice from the upstream slicing machine 13, there would be a gap in the flow of slices on the conveyor, represented by the positions C through i of the job spaces 22. If the downstream slicing machine were to cease earlier, at the time the upstream machine was started, then three additional job space vacancies would occur. Thus it is necessary for the downstream machine to continue depositing slices until enough slices have been deposited by the upstream machine to fill the job spaces between the slice discharge paths of the two machines. To accomplish this, the counter already has made a first count of three and then provided a signal for the retraction of the three slices. it then makes a further count of eight before providing a signal to cause the downstream slicing machine 11 to cease producing slices as detailed hereinafter. Accordingly, the first accepted slice deposited on the first count of the eight by the upstream slicing machine 13 at position B has advanced by the eighth count to the position I. The position 1 is adjacent the position 1, which is in registry with the discharge path of the slices deposited through the eighth count by the downstream slicer 11. Thus, by continuing the depositing from the downstream machine during the three count and the eight count, continuity of slices on the conveyor is maintained. The proximity limit switch 67 on the downstream machine 11 is positionally adjusted initially to provide its signal at a time when at least eleven more slices remain on the heel of the cheese bar being sliced.

After the eighth accepted slice has been cut on the upstream slicer 13, the counter 157 provides a signal that resets the counter, disables the counter input, stops the downstream feed screw drive motor 61, energizes the downstream reject solenoid valve 153 and deenergizes the downstream accept solenoid valve 155, energizes the downstream side clamp out solenoid valve 97 and deenergizes the downstream side clamp in solenoid valve 95, and actuates the timer 87 to begin timing. The timer 87 is an adjustable, resettable timer that may have any suitable adjustment range for timing, but preferably has a range from one-tenth of a second to 10 seconds. As mentioned previously, the purpose of the timer is to create a sufficient delay at the conclusion of slicing to prevent the product safety stop 29 from being lowered until the heel 39 of the cheese bar is removed from the path of the rotating blade 31 by the retraction of the carriage 55. At the conclusion of the preset time period,.the timer 87 provides a signal that energizes the downstream safety down solenoid valve 93 and deenergizes the downstream safety up solenoid valve 91. By this time, the side clamp of the downstream slicer 11 has been released, the carriage of the downstream slicer 11 has been retracted to the load-unload position, and the reject tray of the downstream slicer 11 has been extended to the reject position. Thus, the downstream machine is idled.

The vacuum on the downstream slicer 11 is then turned off (switch not shown) and the heel of the cheese bar is removed from the vacuum head 43. A new bar of cheese is placed against the product safety stop 29 and the other steps for loading the new bar described previously are complete-d. When the vacuum interlock switch 165 is again actuated, a signal is provided that energizes the downstream side clamp in solenoid valve and the vacuum system is again enabled. The downstream slicer 11 now remains idle, but is held in readiness by its connection to the logic circuit 163 to receive the next actuating signal from the upstream machine as its supply becomes exhausted.

As the heel of cheese on the upstream slicer l3 approaches the rotating blade, the upstream proximity limit switch 67a detects the approach of the carriage extension arm 57 on that machine and provides a signal that energizes the upstream reject solenoid valve 153a and deenergizes the upstream accept solenoid valve a, enables the input of the counter 157, stops the upstream feed screw drive motor 61a, energizes the upstream side clamp out solenoid valve 97a and deenergizes the upstream side clamp in solenoid valve 95a, and actuates the timer 87a to begin timing.

Upon timing out of the preset time, the timer 87a provides a signal that energizes the upstream safety down solenoid valve 93a and deenergizes the upstream safety up solenoid valve 91a. Thus, the upstream slicer is idled immediately upon its proximity limit switch providing a signal, and a signal has yet not been provided for actuating the downstream slicer. For a time, neither slicer is depositing or even cutting slices. Accordingly, the upstream proximity limit switch 67a need not be positionally adjusted to have slices remain ing on the cheese heel when it provides its signal.

Referring again to FIG. 7, if when the upstream proximity limit switch provides a signal the downstream slicer 11 were immediately to begin depositing slices onto the conveyor at the position J, it can be seen that there would be double slices on certain of the job spaces 22 until the job space having the last discharged slice from the upstream slicer advances to the position K. To prevent overlapping, the counter 157 at this point makes a count of six followed by a separate count of three. At the conclusion of the count of six, the counter provides a signal that resets the counter, starts the downstream feed screw drive motor 61, energizes the downstream safety up solenoid valve 91 and deenergizes the downstream safety down solenoid valve 93. With the feed screw drive motor started, the cheese bar is advanced into the path of the rotating blade 31, and slicing commences. Then the separate count of three begins, and at the conclusion of this count, the counter provides a signal that resets the counter; disables the input of the counter 157, energizes the downstream accept solenoid valve 155 and deenergizes the downstream reject solenoid valve 153. Thus, a total of nine counts occur after depositing of the last slice from the upstream slicer 13 before a first slice is deposited onto the conveyor from the downstream slicer 11. As can be seen in FIG. 7, the last slice from the upstream slicer is deposited onto the conveyor 15 at position B. At the first count following the depositing of the last slice, the slice advances to the position C. At the second count, the slice advances to the position D, and so on. By the ninth count, the slice has advanced to the position K, leaving the first job space behind K at the position J available for receiving the first accepted slice from the downstream slicer 11. During this time, the first three slices of the new product bar on the downstream slicer 11 have been caught and removed by the reject tray 117.

Thus, it is seen that the normal operative functions of each machine, such as the rejection of the first three slices of each cheese bar, continue to occur within the functioning of the sequence control 17. Yet transfer of the slicing operation from either machine to the other occurs without disturbing the predetermined flow of slices on the conveyor 15. It is also seen that a correlation exists between the predetermined count of the counter and the spaced apart distance of the machines in tandem along the conveyor.

At this point, the cheese heel from the upstream slicer 13 is removed and replaced with a new cheese bar. The upstream slicer is then maintained in readiness by its connection to the logic circuit 163, and the cycle repeats itself upon the downstream proximity limit switch 67 providing its next signal.

Briefly summarizing, a method and apparatus has been set forth for controlling a plurality of slicing machines in tandem on a conveyor line so that a predetermined flow of slices from the slicing machines will result on the conveyor line. While one slicing machine is depositing slices on the conveyor, the other is loaded and stands by in readiness. As the machine slicing exhausts its effective supply of material to be sliced, the control automatically transfers the slicing operation to the idle machine. Then the first machine is idled to have its supply replenished and is held in readiness. The conditions are not the same when transferring the slicing operation from the downstream machine to the upstream machine as they are when transferring from the upstream machine to the downstream machine. Since the downstream is closer to a subsequent work station on the conveyor than the upstream machine, the upstream machine is controlled to commence depositing slices before the downstream machine stops depositing them. Conversely, when the upstream machine exhausts its effective supply, the downstream machine is controlled to delay deposition of slices until the first vacant job space on the conveyor passes beneath the slice discharge path of the downstream slicer. During the transfer in either direction, it is a normal function of each slicing machine to intercept and remove the first three slices of each new product bar. The method and apparatus of the invention include this normal function in the sequencing of the machines. Although the preferred embodiment of the present invention has set forth cheese as the product handled, it will be understood that the method and the apparatus need not be limited to cheese, but may be applied to depositing other articles on a conveyor.

Thus, itis apparent that there has been provided, in accordance with the invention, a method for sequencing slicing machines in tandem on a common conveyor line to produce a predetermined flow of slices for a subsequent downstream work station that fully satisfies the objects, aims and advantages set forth above. While the invention is susceptible to various other modifications and alternative constructions that may be apparent to those skilled in the art in view of the foregoing description, only a preferred embodiment has been shown in the drawings and described in detail. Such disclosure is not intended to limit the invention. The aim is to cover all modifications and alternative constructions and methods falling within the spirit and scope of the invention as expressed in the appended claims.

Various of the features of the invention are set forth in the following claims.

What is claimed is:

l. A method of depositing articles at uniformly spaced positions on a conveyor moving at a constant speed in a given direction, the depositing occurring from at least two dispensers arranged in tandem and spaced apart a predetermined distance adjacent the conveyor so that one of the dispensers is downstream of another with respect to the direction of movement of the conveyor, the depositing from the tandem dispensers occurring in such a manner as to maintain a predetermined flow of the articles on the conveyor, comprising the steps of: dispensing articles onto the conveyor from a first of the dispensers while a second of the dispensers is idle; transmitting a signal to the idle second dispenser when a predetermined number of articles remain in the effective supply of the first dispenser; idling the first dispenser when its effective supply is exhausted; and controllably actuating the idle second dispenser in response to said signal as a function of the predetermined distance between the dispensers, the actuating of the second dispenser being effected prior to the idling of the first dispenser when the first dispenser is the downstream dispenser and subsequent to the idling of the first dispenser when the first dispenser is the upstream dispenser so as to maintain the predetermined flow of articles on the conveyor.

2. A method of depositing food slices at uniformly spaced positions on a conveyor moving at a constant speed in a given direction, the depositing occurring from two slicing machines, each having a limited capacity and being arranged in tandem adjacent the conveyor and disposed so that one slicing machine is downstream a predetermined distance of the other with respect to the direction of movement of the conveyor, the depositing from the tandem machines occuring in such a manner as to maintain a predetermined flow of food slices on the conveyor, comprising the steps of: dispensing slices onto the conveyor at a uniform rate from the downstream machine while the upstream machine is idle; transmitting a first signal to the idle upstream machine when predetermined number of slices remain in the effective supply of the downstream machine; actuating the idle upstream machine in response to said first signal to commence dispensing slices onto the conveyor a first given period of time-before idling the downstream machine, said first given period of time being equal to the time it takes for the first slice dispensed onto the conveyor by the upstream machine to arrive at a position on the conveyor in register with the downstream machine; idling the downstream slicing machine when the first slice dispensed onto the conveyor by the upstream machine is in register with the downstream machine; transmitting a second signal to the idle downstream machine when a predetermined number of slices remain in the effective supply of the upstream machine; idling the upstream machine at the exhaustion of its effective supply; and actuating the idle downstream machine in response to said second signal to commence dispensing slices onto the conveyor a second given period of time after the upstream machine is idled, said second given period of time being equal to the time it takes for a first vacant slice position on the conveyor to arrive in register with the downstream machine.

3. The method recited in claim 2 wherein said first and second given periods of time are determined by the steps of: sensing each spaced slice position on the moving conveyor from a given point along the conveyor; transmitting a signal to a counter for each slice position that passes said given point; and counting the slice positions passing said given point in response to said slice position signals, said first given period of time being equal to the time it takes to count a number equivalent to the number of slice positions in the predetermined distance between the tandem machines, and said second given period of time being equal to the time it takes to count a number equivalent to one more than the number of slice positions in the predetermined distance between the tandem machines.

4. The method recited inclaim 2 wherein actuating the idle upstream machinein response to said first signal further includes the step of rejecting a predetermined number of initial slices from a new supply before said first given period of time and wherein actuating the idle downstream machine in response to said second signal further includes the step of rejecting a predetermined number of initial slices from a new supply during said second given period of time.

5. Apparatus for depositing food slices at uniformly spaced positions on a conveyor moving at a constant speed in a given direction, the depositing occurring at two separate positions in tandem adjacent the conveyor, the positions being spaced apart along the conveyor a predetermined distance with one of the positions being downstream of the other in relation to the direction of movement of the conveyor, and the depositing occurring in such a manner as to maintain a predetermined flow of food slices on the conveyor, comprising: slicingrneans having a limited capacity disposed at each of said positions for dispensing slices onto the conveyor at a uniform rate; means for actuating the downstream slicing means to dispense slices onto the conveyor until its effective supply is exhausted while the upstream slicing means is idle; means for transmitting a first signal to the idle upstream slicing means when a predetermined number of slices remain in the effective supply of the downstream slicing means; means for actuating the idle upstream slicing means in response to said first signal to commence dispensing slices onto the conveyor a first given period of time before idling the downstream slicing means, said first given period of time being equal to the time it takes for the first slice dispensed onto the conveyor by the upstream slicing means to arrive at a position on the conveyor in register with the downstream slicing means; means for idling the downstream slicing means when the first slice dispensed onto the conveyor by the upstream slicing means is in register with the downstream slicing means; means for transmitting a second signal to the idle downstream slicing means when a predetermined number of slices remain in the egffectiye supply of the upstream s'licin means; means or idling the upstream s icing means a the exhaustion of its effective supply; and means for actuating the idle downstream slicing means in response to said second signal to commence dispensing slices onto the conveyor a second given period of time after the upstream slicing means is idled, said second given period of time being equal to the time it takes for a first vacant slice position on the conveyor to arrive in register with the downstream slicing means.

6. The apparatus recited in claim 5 further comprising: sensing means for detecting each spaced slice position on the moving conveyor from. a given point along the conveyor; a counting means; means for transmitting a signal to said counting means for each slice position that passes said given point; said counting means responding to said slice position signals for determining said first and second given periods of time, said first given period of time being equal to the time it takes to count a number equivalent to the number of slice positions in the predetermined distance between the tandem machines, and said second given period of time being equal to the time it takes to count at number equivalent to one more than the number of slice positions in the predetermined distance between the tandem machines.

Claims

1. A method of depositing articles at uniformly spaced positions on a conveyor moving at a constant speed in a given direction, the depositing occurring from at least two dispensers arranged in tandem and spaced apart a predetermined distance adjacent the conveyor so that one of the dispensers is downstream of another with respect to the direction of movement of the conveyor, the depositing from the tandem dispensers occurring in such a manner as to maintain a predetermined flow of the articles on the conveyor, comprising the steps of: dispensing articles onto the conveyor from a first of the dispensers while a second of the dispensers is idle; transmitting a signal to the idle second dispenser when a predetermined number of articles remain in the effective supply of the first dispenser; idling the first dispenser when its effective supply is exhausted; and controllably actuating the idle second dispenser in response to said signal as a function of the predetermined distance between the dispensers, the actuating of the second dispenser being effected prior to the idling of the first dispenser when the first dispenser is the downstream dispenser and subsequent to the idling of the first dispenser when the first dispenser is the upstream dispenser so as to maintain the predetermined flow of articles on the conveyor.

2. A method of depositing food slices at uniformly spaced positions on a conveyor moving at a constant speed in a given direction, the depositing occurring from two slicing machines, each having a limited capacity and being arranged in tandem adjacent the conveyor and disposed so that one slicing machine is downstream a predetermined distance of the other with respect to the direction of movement of the conveyor, the depositing from the tandem machines occuring in such a manner as to maintain a predetermined flow of food slices on the conveyor, comprising the steps of: dispensing slices onto the conveyor at a uniform rate from the downstream machine while the upstream machine is idle; transmitting a first signal to the idle upstream machine when predetermined number of slices remain in the effective supply of the downstream machine; actuating the idle upstream machine in response to said first signal to commence dispensing slices onto the conveyor a first given period of time before idling the downstream machine, said first given period of time being equal to the time it takes for the first slice dispensed onto the conveyor by the upstream machine to arrive at a position on the conveyor in register with the downstream machine; idling the downstream slicing machine when the first slice dispensed onto the conveyor by the upstream machine is in register with the downstream machine; transmitting a second signal to the idle downstream machine when a predetermined nUmber of slices remain in the effective supply of the upstream machine; idling the upstream machine at the exhaustion of its effective supply; and actuating the idle downstream machine in response to said second signal to commence dispensing slices onto the conveyor a second given period of time after the upstream machine is idled, said second given period of time being equal to the time it takes for a first vacant slice position on the conveyor to arrive in register with the downstream machine.

4. The method recited in claim 2 wherein actuating the idle upstream machine in response to said first signal further includes the step of rejecting a predetermined number of initial slices from a new supply before said first given period of time and wherein actuating the idle downstream machine in response to said second signal further includes the step of rejecting a predetermined number of initial slices from a new supply during said second given period of time.

5. Apparatus for depositing food slices at uniformly spaced positions on a conveyor moving at a constant speed in a given direction, the depositing occurring at two separate positions in tandem adjacent the conveyor, the positions being spaced apart along the conveyor a predetermined distance with one of the positions being downstream of the other in relation to the direction of movement of the conveyor, and the depositing occurring in such a manner as to maintain a predetermined flow of food slices on the conveyor, comprising: slicing means having a limited capacity disposed at each of said positions for dispensing slices onto the conveyor at a uniform rate; means for actuating the downstream slicing means to dispense slices onto the conveyor until its effective supply is exhausted while the upstream slicing means is idle; means for transmitting a first signal to the idle upstream slicing means when a predetermined number of slices remain in the effective supply of the downstream slicing means; means for actuating the idle upstream slicing means in response to said first signal to commence dispensing slices onto the conveyor a first given period of time before idling the downstream slicing means, said first given period of time being equal to the time it takes for the first slice dispensed onto the conveyor by the upstream slicing means to arrive at a position on the conveyor in register with the downstream slicing means; means for idling the downstream slicing means when the first slice dispensed onto the conveyor by the upstream slicing means is in register with the downstream slicing means; means for transmitting a second signal to the idle downstream slicing means when a predetermined number of slices remain in the effective supply of the upstream slicing means; means for idling the upstream slicing means at the exhaustion of its effective supply; and means for actuating the idle downstream slicing means in response to said second signal to commence dispensing slices onto the conveyor a second given period of time after the upstream slicing means is idled, said second given period of time being equal to the time it takes for a first vacant slice position on the conveyor to arrive in register with the downstream slicing means.

6. The apparatus recited in claim 5 further comprising: sensing means for detecting each spaced slice position on the moving conveyor from a given point along the conveyor; a counting means; means for transmitting a signal to said counting means for each slice position that passes said given point; said counting means responding to said slice position signals for determining said first and second given periods of time, said first given period of time being equal to the time it takes to count a number equivalent to the number of slice positions in the predetermined distance between the tandem machines, and said second given period of time being equal to the time it takes to count a number equivalent to one more than the number of slice positions in the predetermined distance between the tandem machines.