US3915310A

US3915310A - Machine for emptying trays

Info

Publication number: US3915310A
Application number: US404285A
Authority: US
Inventors: Eric Wood
Original assignee: Monomech Developments Ltd
Current assignee: Monomech Developments Ltd
Priority date: 1973-10-09
Filing date: 1973-10-09
Publication date: 1975-10-28
Anticipated expiration: 1992-10-28

Abstract

A machine for emptying trays comprising a tipping station where each tray is tipped by a tipping mechanism from an initial position to a tipped position and a de-stacking station whereat the top or bottom tray of a stack of full trays is separated by a de-stacking mechanism from the remainder of the stack, the destacker and tipping mechanism being operated from a common drive. Preferably there is a re-stacking mechanism for re-stacking empty trays and this also is driven by the common drive.

Description

Unlted States Patent 1 1 1111 3,915,310 Wood Oct. 28, 1975 MACHINE FOR EMPTYING TRAYS 3,190,466 6/1965 1165161161 214/6 BA 3,347,400 10/1967 Ridder [75] Inventor Em Wood 0556, England 3,421,638 1/1969 Locke et a1. 214/6 BA [73] A i M h Developments Limited, 3,666,126 5/1972 Rempel 214/313 X Yorkshire, England Primary Examiner-Stanley H. Tollberg [22] Ffled' 1973 Assistant Examiner-Hadd S. Lane 21] A N 404 235 Attorney, Agent, or Firm-Wolf, Greenfield & Sacks [52] US. Cl. 214/1 GD; 2l4/8.5 K; 214/306; [57] APSTRACT 214314 A machme for emptying trays comprising a t1pp1ng 51 int. c1. 865G 59/00 Station where each tray is tipped by tiPPiIg mecha- [58] Field of Search 214/6 BA, 85 K, 314 313, nism from an initial position to a tipped position and a 214 GD 300 306 312 318 de-stackmg stat1on whereat the top or bottom tray of a stack of full trays is separated by a de-stacking [56] References Cited mechanism from the remainder of the stack, the destacker and tipping mechanism being operated from a UNITED STATES PATENTS common drive. Preferably there is a re-stacking mechif 2 1 anism for re-stacking empty trays and this also is en 2,769,570 11/1956 Adams 2l4/8.5 K dnven by the common driva- 3,013,680 12/1961 Paxton 214/312 X 11 Claims, 1 Drawing Figure US. Patent Oct. 28, 1975 MACHINE FOR EMPTYING TRAYS This invention relates to a machine for emptying trays. The nature of the contents of the trays is not material to the invention, but for example such contents may be a plurality of small articles or objects or a semifluent material such as powder or soil or the like. An application of the invention in which we are interested is the emptying of trays containing mushroom growing compost.

The machine of the invention is concerned in addition to the emptying of trays, with the handling of stacks of trays; on the one hand the de-stacking of full trays and on the other hand the re-sta'cking of empty trays.

According to one aspect of the invention, there is provided a machine for emptying trays comprising a tipping station whereat each tray is tipped by a tipping mechanism from an initial position to a'tipped position to empty the contents of the tray and then returned to the initial position, a de-stacking station whereat the top or bottom tray of a stack of full trays is separated by a tie-stacking mechanism from the remainder of the stack, and a common drive mechanism serving to operate the tipping mechanism and the de-stacking mechanism so that during the period between tipping a tray from the initial position to the tipped position and returning the tray to the initial position, another full tray is separated by the de-stacking mechanism from the re mainder of the stack.

According to another aspect of the invention there is provided a machine for emptying trays comprising a tipping station whereat each tray is tipped by a tipping mechanism from an initial position to a tipped position to empty the contents of the tray and then returned to the initial position, a tray stacking station whereat a tray which has previously been emptied at the tipping station is added to a stack of empty trays by a stacking mechanism, and a common drive mechanism serving to operate the tipping mechanism and the stacking mechanism so that during the period between tipping a tray from the initial position to the tipped position and returning the tray to the initial position, another tray which has previously been emptied of its contents at the tipping station is added by the stacking mechanism to a stack of empty trays.

According to a third aspect of the invention there is provided a machine for emptying trays comprising a tipping station whereat each tray is tipped by a tipping mechanism from an initial position to a tipped position to empty the contents of the tray and then returned to the initial position, a tie-stacking mechanism whereat the top or bottom tray of a stack of full trays is separated by a de-stacking mechanism from the remainder of the stack, a tray staking mechanism whereat each tray which has previously been emptied at the tipping station is added to a stack of empty trays by a stacking mechanism, and a common drive mechanism serving to operate the tipping mechanism, the de-stacking mechanism and the stacking mechanism so that during the period between the tipping a tray from the initial position to the tipped position, and returning the tray to the initial position, another full tray is separated by the destacking mechanism from the remainder of the stacking mechanism to the stack of empty trays.

The common drive mechanism preferably comprises a shaft which is rocked back and forth by means of hy- 2 draulic ram means, the tipping mechanism, de-stacking mechanism and stacking mechanism being drivingly connected to said shaft.

Preferably also, there is means defining a feed track for the trays the arrangement being that when the tipping mechanism returns to the initial position after emptying a tray, it deposits the empty tray on the track the destacking mechanism has meanwhile deposited another full tray on the track and the stacking mechanism has removed an empty tray from the track; and including pusher means which operates when the tipping mechanism is in the initial position to push the full tray and the empty tray respectively into and out of the tipping station ready for said tipping mechanism to empty the full tray.

The empty tray pushed out of the tipping station may either be pushed into a store station on the track or directly into the stacking station to be added to the stack of empty trays. In any event during each operation of the pusher means a tray previously emptied at the tipping station will be pushed into the stacking station.

There may be two store stations on the track between the tipping station and the stacking station, in which case each tray emptied at the tipping station would be placed in the stacking station three cycles of the machine later.

An embodiment of the invention will now be described by way of example, with reference to the accompanying drawing, the single FIGURE of which shows in perspective elevation, a machine according to the invention.

Referring to the drawing, the machine comprises an open work elongated box frame indicated generally by the reference numeral 10 having lower longitudinal frame members 12 and upper longitudinal frame members 14 these being connected by cross braces 16.

At the left hand end of the machine there is a destacking station 18 whereat there is located a support frame 20 for a stack of full trays of mushroom growing compost one such tray 22 being shown carried on the frame 20. The frame 20 is carried by the main frame 10 and it is constituted by a pair of side assemblies which can swing outwardly relative to the main frame 10 as indicated by arrows 23 and as will be explained in more detail hereinafter. The de-stacking station 18 further includes a de-stacking mechanism in the form of a cage 24 which comprises a lower transverse bar 26 with an upstanding leg 28 at each end thereof. At the top of each leg 28 is a support rail 30. The two legs 28 are constituted by spaced members and cross frame member 29 locates between the members to guide the cage in its up and down movement.

Adjacent the right hand end of the de-stacking station is a tray tipping station 34 which includes a tray holding cage made up of longitudinally extending rail 38 which are secured to pivot arms 40, these arms in turn being secured to a shaft 42 located at the side of the machine and extending in the direction of the length thereof. This shaft 42 is supported on four pedestals 44 each having a bearing for the shaft at the top end thereof. Rotation of shaft 42 causes tipping of the cage as indicated by arrow 36 to a tipping position in which the contents of the tray are tipped out into a suitable receptacle. Rotation of the shaft 42 is obtained by means of two pairs of hydraulic rams 46, 48 each ram 46, 48 having a cable 50, 52 attached to the movable piston thereof and wrapped round drive wheel 54 secured to shaft 42, the free end of each cable 50, 52

3 being anchored to such wheel 54 and the cables 50, 52

being wrapped round the wheel 54 in opposite directions so that by alternately pressurising the cylinders 46, 48 the tipping cage at the tipping station is moved from the initial position shown in the drawing to the tipping position and then back to the initial position.

To the right hand side of the tipping station in FIG. 2 there are two store stations indicated by numeral 55 and an empty tray stacking station 56 which includes an empty tray stacking mechanism defined by a cage arrangement 56 similar to the cage 24 and having rails 60. The stacking station in addition is defined by upright posts 62 located at each side of the machine, each post 62 having a pivotal stacking catch 64, and these catches co-operate to hold the empty stack of trays clear of the rails 60 to allow an empty tray which is to be added to the stack to be located under the stack as will be explained with refernce to the operation of the machine.

The rotation of the shaft 42 to effect the tipping movements of cage 38 is utilized to effect the operation of the de-stacking mechanism and the stacking mechanism at the respective stations 18, 56 insofar as at the left hand end of the shaft 42 there is secured a lifting cam 66 to which are attached two lengths of cable 68. These cable lengths pass over guide pulleys 70 mounted on cross bar 29 of the main frame and the other ends of the cables 68 are attached to the cross brace 26 of cage 24 as shown. A similar arrangement is used at the other end of shaft 42, the lifting cam for the stacking cage being indicated at 72. Cam 72 may be of a circular configuration whilst cam 66 has a progressively decreasing radius in an anti-clockwise direction in the drawing.

Finally, the machine has a transverse pusher ram 75 to which is connected a pusher bar 76. Mounted on the pusher bar 76, at a pitching corresponding to the tray dimension are a plurality of spring loaded catches 74 which are spring loaded to occupy the positions shown and can be deflected downwards as the pusher bar is being pulled back under a row of trays. The transverse ram and the bar 76 extend in the direction of the length of the machine and are located on the approximate centre line thereof.

In operation of the machine, a stack of full trays is placed by, for example a fork lift truck on the top of the de-stacker sub-frame the parts of the machine being in the position as shown in the drawing. In the next operation rams 48 are pressured thereby pulling on its cable 52. The effect of this is to cause rotation of shaft 42 in a clock-wise direction whereby the tipping cage swings in the direction of arrow 36 to the tipping position. At the same time, the cage 24 of the de-stacker mechanism is lifted via cam 66 and cables 68 until the rails engage the underside of the stack of trays at the de-stacker station. By this time the cam 66 will have rotated to a position in which the effective lifting radius thereof will have decreased considerably and the mechanism will now be in a position to yield a high mechanical advantage in order to lift the stack of full trays. This effort may be considerable as the machine illustrated is designed to lift 5 or 6 full trays each having contents weighing approximately 6 to 7 cwt. At this stage in the movement, therefore, the lifting proceeds more slowly than in the initial stages. As the stack of trays is lifted off the subframe 20 so the two side assemblies are pivoted outwards by a cam action between cage 24 and the side assemblies as indicated by arrows 23. When 4 the tipping cage reaches the tipping position, the stack of full trays has been lifted off the sub-frame 20. Simul taneously, with the lifting of the cage 24 the cage at the stacking station is also lifted. There is. however, at this time no tray at the stacking station nor is there a tray in the tipping cage.

In the next stage of movement, the rams 46 are pressurized and this rotates the shaft 42 in an anti-clock wise direction returning the tipping cage to the initial position. At the same time the cage 24 with the stack of full trays thereon is lowered and after a pre-determined amount of such lowering the side assemblies of subframe 20 again swing inwards for example under spring action to the position shown, the instant of this action being selected so that the sub assemblies engage under the second full tray in the stack. Continued lowering of the cage 24 separates the bottom tray from the stack. At the end of the lowering movement of cage 24, the left hand side of the lowered tray is presented to a pusher lug secured to the extreme left hand end of bar 76 and it is located so that its rails 30 are aligned with rails 38 of the tipping cage. The transverse ram is now pressurized and extended whereby pusher bar 76 via lug 75 pushes the full tray into the tipping cage. The traverse ram is then moved back to its initial position during which movement the first spring catch 74 is deflected downwards and passes under the fall tray in the tipping station when the said catch clears the cage, it springs upwards so that it can engage the left hand end of the cage in the next traverse of the pusher bar 76. Immediately the pusher bar 76 has completed its forward movement, the rams 48 are again pressured causing the full tray in the tipping station to be tipped as described previously and again the cage 24 is simultaneously elevated to separate, as explained, the lowermost tray in the stack of full trays from the remainder of the stack. The traverse ram is returned to the initial position before the tipping cage is returned to the initial position and the de-stacking cage 24 has returned to its initial position bringing with it another full tray. There is now a full tray in the de-stacking station and an empty tray in the tipping station. When the traverse ram is next pressurized both of these trays are moved forward to the next station so that an empty tray is pushed into the first store station 55. Because there are two store stations 55, it takes five cycles of the machine from starting before the first empty tray reaches the stacking station. In the sixth cycle, when the tipping cage is moved to the tipping position the lifting cage of the stacking station is also elevated and this lifts the empty tray in the stacking station above the holding catches 64 of the stacking station. In the subsequent return movement of the tipping cage and the lowering of the stacking cage and the de-stacking cage 24, the position is arrived at where there is a full tray in the destacking station, an empty tray in the tipping cage, an empty tray in each store station and an empty tray held by catches 64, the last named forming the first empty tray of a stack of empty trays to be built up at the stacking station. The cycle is repeated until all the full trays have been emptied and stacked at the stacking station 56 whereupon the stack of empty trays is then removed from the machine. Loading and unloading of the machine can, of course take place continuously.

in some instances, it may be possible to utilize the machine without a stacking station in which case the trays would have to be removed individually from the tipping station and, in another instance, it may be possible to eliminate the de-stacking station in which case the full trays would have to be loaded into the tipping station individually.

Moreover, various modifications are possible for the common drive arrangement. in the example described we have illustrated four cylinders 46, 48 as constituting the prime movers but in an alternative, the rams 46 could be eliminated and a strong spring used for effecting the return movement of the tipping cage because the weight cages at the de-stacking station would assist in returning the tipping cage to the initial position.

The various hydraulic cylinders used in the machine would be inter-connected by appropriate circuitry in order to give the desired sequence of operations.

What we claim is:

l. A machine for emptying trays comprising 1. a tray tipping mechanism disposed at a tipping station, the tipping mechanism causing each tray to be moved from an initial horizontal position to a tipped position to empty the contents of the tray and then returned to the initial position,

2. a de-stacking mechanism disposed at a de-stacking station, the de-stacking mechanism causing individual trays of a stack of full trays to be separated from the stack,

3. horizontal decking extending between the destacking station and the tipping station,

4. a common drive mechanism coupled to the tipping mechanism and the de-stacking mechanism whereby during the period between tipping of a tray and its return to the initial horizontal position, a full tray is separated from the stack of full trays,

5. and pusher means for pushing the previously separated full tray from the de-stacking station to the tipping station after the tipping mechanism has returned from the tipped position to the initial position.

2. The machine according to claim 1, wherein the common drive mechanism includes a. a drive shaft,

b. drive means adapted to alternately turn the shaft in one direction and then in the other direction,

c. and means drivingly connecting the shaft to the tipping mechanism and the de-stacking mechanism.

3. The machine according to claim 2, wherein the de-stacking mechanism includes a cage that is raised by the turning of the shaft in one direction and is lowered by opposite rotation of the shaft, the de-stacking mechanism separating the bottom tray of a stack of trays by causing the cage to lift the stack and support the stack while the bottom tray is separated during downward movement of the cage.

4. The machine according to claim 3, wherein the means drivingly connecting the shaft to the destacking mechanism causes a progressive decrease in the rate of lift of the cage and a progressive increase in lifting force with constant rate of shaft rotation.

5. The machine according to claim 3, wherein with the tipping mechanism in the initial position and the de-stacking cage in its lowest position, a full tray can be moved horizontally off the cage and into the tipping mechanism while an empty tray is moved horizontally out of the tipping mechanism,

the machine including a reciprocating pusher means for so moving the trays, the pusher means pushing the trays the trays in one direction only.

6. A machine for emptying trays comprising 1. a tray tipping mechanism disposed at a tipping station, the tipping mechanism causing each tray to be moved from an initial horizontal position to a tipped position to empty the contents of the tray and then returned to the initial position,

2. a stacking mechanism disposed at a stacking station, the stacking mechanism causing a tray which was previously emptied at the tipping station to be added to a stack of empty trays, I

3. a common drive mechanism coupled to the tipping mechanism whereby in the interval between tipping of a tray and its return to the horizontal position, a tray which was previously emptied at the tipping station is added to the stack of empty trays,

4. horizontal decking extending between the stacking station and the tipping station,

5. and pusher means for pushing the empty trays from the tipping station to the stacking station along the decking after the tipping mechanism has returned from the tipped position to its initial position.

'7. The machine according to claim 6, wherein the machine further comprises first and second store stations on the decking between the tipping mechanism and the stacking mechanism,

and the pusher means causing the trays emptied at the tipping station to be moved in turn to the first store station, the second store station, and the stacking station.

8. The machine according to claim 6, wherein the common drive mechanism includes a. a drive shaft,

b. drive means adapted to alternately turn the shaft in one direction and then in the other direction, c. and means drivingly connecting the shaft to the tipping mechanism and the stacking mechanism.

9. The machine according to claim 8, wherein the stacking mechanism includes a cage raised by the turning of the shaft in one direction and lowered by opposite rotation of the shaft, the stacking mechanism adding an empty tray to the bottom of a stack of trays located above the cage by raising the empty tray into engagement with the bottom of the stack and causing the cage to lift the whole stack until the bottom tray passes catches which support the stack, the catches supporting the stack while the cage moves downward and disengages itself from the stack.

10. The machine according to claim 9, wherein with the tipping mechanism in its initial position and the stacking cage in its lowest position, an empty tray can be pushed horizontally out of the tipping mechanism into a first store station while a previously emptied tray is moved from the first store station into the stacking station, and the pusher means pushing the trays in one direction only.

11. A machine for emptying trays comprising 1. a tipping mechanism situated at a tipping station, the tipping mechanism causing each tray entering the tipping station to be moved from an initial horizontal position to a tipped position to empty the contents of the tray and then returned to the initial position,

8 zontal position, a full tray is separated from the stack of full trays and another tray is added to the stack of empty trays, 5. horizontal decking extending from the de-stacking station and stacking stations to the tipping station, 6. and pusher means for pushing the full trays along the decking from the de-stacking station into the tipping station and for pushing empty trays from the tipping station to the stacking station after the tipping mechanism has returned from the tipped position to its initial position.

Claims

1. A machine for emptying trays comprising

1. a tray tipping mechanism disposed at a tipping station, the tipping mechanism causing each tray to be moved from an initial horizontal position to a tipped position to empty the contents of the tray and then returned to the initial position,

1. a tipping mechanism situated at a tipping station, the tipping mechanism causing each tray entering the tipping station to be moved from an initial horizontal position to a tipped position to empty the contents of the tray and then returned to the initial position,

2. a stacking mechanism disposed at a stacking station, the stacking mechanism causing a tray which was previously emptied at the tipping station to be added to a stack of empty trays,

2. The machine according to claim 1, wherein the common drive mechanism includes a. a drive shaft, b. drive means adapted to alternately turn the shaft in one direction and then in the other direction, c. and means drivingly connecting the shaft to the tipping mechanism and the de-stacking mechanism.

3. horizontal decking extending between the de-stacking station and the tipping station,

3. a tray stacking mechanism disposed at a stacking station, the stacking mechanism causing a tray which was previously emptied at the tipping station to be added to a stack of empty trays,

4. The machine according to claim 3, wherein the means drivingly connecting the shaft to the de-stacking mechanism causes a progressive decrease in the rate of lift of the cage and a progressive increase in lifting force with constant rate of shaft rotation.

4. a common drive mechanism coupled to the tipping mechanism, the de-stacking mechanism, and the stacking mechanism whereby in the interval between tipping of a tray and its return to the horizontal position, a full tray is separated from the stack of full trays and another tray is added to the stack of empty trays,

5. horizontal decking extending from the de-stacking station and stacking stations to the tipping station,

5. The machine according to claim 3, wherein with the tipping mechanism in the initial position and the de-stacking cage in its lowest position, a full tray can be moved horizontally off the cage and into the tipping mechanism while an empty tray is moved horizontally out of the tipping mechanism, the machine including a reciprocating pusher means for so moving the trays, the pusher means pushing the trays the trays in one direction only.

6. A machine for emptying trays comprising 1. a tray tipping mechanism disposed at a tipping station, the tipping mechanism causing each tray to be moved from an initial horizontal position to a tipped position to empty the contents of the tray and then returned to the initial position, 2. a stacking mechanism disposed at a stacking station, the stacking mechanism causing a tray which was previously emptied at the tipping station to be added to a stack of empty trays, 3. a common drive mechanism coupled to the tipping mechanism whereby in the interval between tipping of a tray and its return to the horizontal position, a tray which was previously emptied at the tipping station is added to the stack of empty trays, 4. horizontal decking extending between the stacking station and the tipping station, 5. and pusher means for pushing the empty trays from the tipping station to the stacking station along the decking after the tipping mechanism has returned from the tipped position to its initial position.

7. The machine according to claim 6, wherein the machine further comprises first and second store stations on the decking between the tipping mechanism and the stacking mechanism, and the pusher means causing the trays emptied at the tipping station to be moved in turn to the First store station, the second store station, and the stacking station.

8. The machine according to claim 6, wherein the common drive mechanism includes a. a drive shaft, b. drive means adapted to alternately turn the shaft in one direction and then in the other direction, c. and means drivingly connecting the shaft to the tipping mechanism and the stacking mechanism.

11. A machine for emptying trays comprising