WO1992006909A1

WO1992006909A1 - A jump conveyor

Info

Publication number: WO1992006909A1
Application number: PCT/GB1991/001752
Authority: WO
Inventors: Trevor Barrie Hoyland
Original assignee: Thurne Engineering Co. Ltd
Priority date: 1990-10-10
Filing date: 1991-10-09
Publication date: 1992-04-30
Also published as: GB9022032D0

Abstract

A jump conveyor for separating slices of product such as food products into groups of slices and conveying the groups of slices downstream. The jump conveyor has a generally flat slice receiving surface to receive the slices of product from an upstream slicing machine, the slice receiving surface being formed from the upper surfaces of a plurality of toothed wheels (2) mounted on a plurality of axles (1). The axles (1) are driven in unison by a driving means (8, 9, 10).

Description

A JUMP CONVEYOR

Technical Field

Foodstuffs such as blocks of cheese, meat or meat products are usually sliced using a slicing machine which cuts slices at a constant rate. To divide such a constant stream of slices into groups of slices to be packed separately the slices fall onto a jump conveyor. The jump conveyor typically moves forwards at a slow rate to create a shingled group of slices and then, when a predetermined number of slices or a predetermined weight of product has been sliced, the jump conveyor is accelerated to accelerate the shingled group of slices so that they briefly travel at high speed. The jump conveyor then returns to its slow speed to receive the subsequently cut slice of product. This jump in speed has the effect of separating adjacent groups of slices so that they can be handled separately during a subsequent packaging operation. Background Art

Traditionally jump conveyors are driven using two separate drives both of which run continuously, one at high speed and the other at low speed. At any instant one of these drives is clutched to the conveyor to drive it at either its high or low speed. An alternative system is to drive the conveyor using a hydraulic motor. In this case the flow of hydraulic fluid to the motor is throttled to provide the low speed drive.

The maximum rate of operating a slicing machine is usually limited by the rate at which the jump conveyor downstream of it en accelerate the group of slices to give the required separation between consecutive groups. Naturally, the faster the slicing rate the shorter the time interval between cutting subsequent slices of product and hence the less time available to separate the groups of slices. As the slicing speed is increased and hence the rate of acceleration of the jump conveyor is increased the groups of slices tend to slip on the jump conveyor. This is described in detail in our earlier patent specification EP-A-0233008 which overcomes this problem by forming the jump conveyor by a support intercallated with a strip conveyor and then, whilst moving the strip conveyor continuously at high speed lifting it up to engage the groups of slices held by the support. The conveyor is urged upwards rapidly at a sufficient speed to produce a reaction force of at least 3g on the group of slices and this ensures that substantially no slip occurs between the group of slices and the conveyor as the group of slices is transferred from the support to the rapidly moving strip conveyor.

US-A-2239665 discloses a conveyor for a slicing machine formed from a plurality of bands running over two rollers. The roller adjacent the slicing machine has a number of radial protuberances for receiving the slices of product from the slicing machine and transferring the product onto the conveyor bands. Disclosure of Invention

According to this invention the jump conveyor comprises a generally flat slice receiving platform which, in use, receives slices cut by a slicing machine, and a means to drive the conveyor at at least two different speeds to convey sliced products along the platform and to marshall slices of product into separate groups characterised in that the generally flat slice receiving platform is formed by the upper surfaces of a plurality of toothed wheels which are mounted on a plurality of axles, and in that the means to drive the conveyor drives all the axles in unison. To form a shingled group of slices the toothed wheels are driven forwards at low speed whilst a number of slices are cut by the slicing machine. To form a stack of slices the wheels may be held stationary or driven backwards, to compensate for the curvature in the flight of each slice as it travels from the slicing machine to the jump conveyor.

To separate each group the drive then accelerates the toothed wheels to drive the group forwards at high speed in the interval between the cutting of consecutive slices. The wheels may also be driven rapidly in a reverse direction to reject any slices that are determined to be unacceptable, for example, those cut from the ends of a block of product or an incomplete group.

The toothed wheels may be formed with a spiked outer periphery but preferably their outer profile is of sawtooth shape with the leading end of each sawtooth facing in the forwards direction of movement of the groups of slices. Preferably, some of the toothed wheels have the leading end of each sawtooth facing in the reverse direction to that of the movement of the groups of slices for rejecting slices.

In one example of the present invention, the generally flat slice receiving platform is formed from a single toothed wheel provided on each axle, each wheel extending across the width of the conveyor in a direction transverse to the forward direction of movement of the group of slices to form a roller. In a preferred example, a plurality of toothed wheels are provided on each axle. In this case the toothed wheels on adjacent axles are preferably intercallated to provide the generally flat slice receiving platform and preferably the teeth on adjacent wheels on each axle are angularly offset from one another so that the teeth are distributed across the platform and not arranged in line.

Preferably the jump conveyor in accordance with this invention is formed in two parts as described in our European application EP-A-0398603. In this case the jump conveyor consists of a first short conveyor which is, in use, adjacent the slicing blade of the slicing machine and which has a length substantially equal to the height capacity of the slicing machine, and a second conveyor downstream of the first conveyor, both conveyors of the jump conveyor having an independent drive and control means to drive the two conveyors at the same speed or at different speeds. The entire first short conveyor is formed in accordance with this invention in that it comprises a slice receiving platform formed by a number of toothed wheels. The second conveyor may also be formed entirely by a number of toothed wheels or entirely by a conventional strip conveyor. Preferably however all of the first short conveyor is formed by a number of toothed wheels and the upstream part of the second conveyor is also formed by a number of toothed wheels. Thus, in this way, the part of the jump conveyor which, in use, carries a shingled group of slices at shingling speed is entirely formed by toothed wheels so that, upon acceleration of a shingled group of slices the entire group of slices is in contact with a conveyor formed by toothed wheels. However, the downstream part of the second conveyor may be formed by a conventional multi-element strip conveyor.

Preferably the toothed wheels are followed by a multi¬ element strip conveyor. In the case where a plurality of wheels are provided on each axle the multi-element strip conveyor is preferably intercallated with the toothed wheels on the downstream axle of the slice receiving platform.

Preferably the, or each, conveyor is driven by a DC brushless motor which has a high torque and is controllable to a high degree. This allows the, or each, conveyor to be both accelerated and decelerated rapidly and controllably in the interval between two successive slices. Preferably the, or each, conveyor is under the control of a programmed computer which is also fed with outputs from the slicing machine to enable the operation of the jump conveyor to be coupled and synchronized with that of the slicing machine. Brief Description of the Drawings

A particular example of a jump conveyor in accordance with this invention will now be described with reference to the accompanying drawings; in which:- Figure l is a plan of a first example of a jump conveyor according to this invention; Figure 2 is a partly sectioned side elevation of the first example;

Figure 3 is a cross-section taken along the lines A-A shown in Figure 2; Figure 4 is a section taken along the lines B-B shown in Figure 2;

Figure 5 is an end elevation of a row of toothed wheels drawn to a larger scale; and,

Figure 6 is a plan of a second example of a jump conveyor according to this invention. Detailed Description

A jump conveyor in accordance with a first example of this invention as shown in Figures 1 to 4 comprises four axles 1, each axle carrying a plurality of toothed wheels 2. The toothed wheels on adjacent axles are intercallated as shown most clearly in Figure 1 so that their upper surface provides a substantially flat platform which receives slices cut by an upstream slicing machine (not shown) . The axles 1 are mounted in rolling bearings 3 held in end plates 4 and 5 and the end plates are connected together by four scraper bars 6 having an upper surface which follows closely the configuration of the toothed wheels on each axle as indicated by reference numeral 7. The scraper bars 6 serve to remove any build up of fat or other deposit on the toothed wheels 2. Drive pulleys 8 are connected to the ends of the axles 1 and are driven from a pair of pulleys 9 which, in turn, are driven from a keyed shaft 10.

The jump conveyor is formed so that it can be disconnected from the slicing machine merely by unscrewing knurled wheel 14 to allow the jump conveyor to be removed from locating pegs 15 and 16.

Since all of the axles are driven from the drive shaft

10 via a belt and pulley system of constant ratio all of the axles 1 rotate at precisely the same angular velocity so that, in use, all of the toothed wheels 2 rotate in unison. Fixed fingers 11, shown most clear in Figures 2 and 4, lie below the top of the toothed wheels 2 and help prevent any pieces of sliced product getting caught in the jump conveyor. The toothed wheels 2 have a sawtooth configuration as shown in Figure 5 with teeth 12 having perpendicular faces 13 facing in the forward feeding direction of the jump conveyor. Some of the toothed wheels 2 have a saw tooth configuration with the perpendicular faces 13 of the teeth 12 facing in the reverse direction to grip the product when slices are being rejected, that is when the conveyor is being driven rapidly in the reverse direction. Figure 5 illustrates teeth 12' of the adjacent toothed wheel 2 and illustrates that the teeth on adjacent toothed wheels 2 are angularly displaced from one another.

A jump conveyor in accordance with a second example of this invention as shown in Figure 6 comprises four axles 1, each axle carrying a single toothed wheel 2 in the form of a roller, thereby forming a substantially flat receiving platform.

Claims

1. A jump conveyor comprising a generally flat slice receiving platform which, in use, receives slices cut by a slicing machine, and a means (8,9,10) to drive the conveyor at at least two different speeds to convey sliced products along the platform and to marshall slices of product into separate groups characterised in that the generally flat slice receiving platform is formed by the upper surfaces of a plurality of toothed wheels (2) which are mounted on a plurality of axles (1), and in that the means (8,9,10) to drive the conveyor drives all the axles (1) in unison.

2. A conveyor according to claim l, in which the outer profile of each toothed wheel (2) is of sawtooth shape.

3. A conveyor according to claim 2, in which the leading edge of each sawtooth (12) faces in the forwards direction of movement of the groups of slices, or in which the leading edge of the majority of the sawteeth (12) face in the forwards direction of movement of the groups of slices and a minority face in the opposite direction to the direction of movement of the groups of slices.

4. A jump conveyor according to any of the preceding claims, in which a single toothed wheel (2) is provided on each axle (1) , the wheel extending substantially across the width of the conveyor in the direction transverse to the direction of travel of the group of slices.

5. A jump conveyor according to claims 1, 2 or 3, in which a plurality of toothed wheels (2) are arranged on each axle (1) with the wheels on adjacent axles being intercallated to provide a platform with a generally flat upper surface.

6. A jump conveyor according to claim 5, in which the teeth (12) on adjacent wheels (2) of the same axle are angularly offset from one another so that the teeth (12) are distributed across the platform and not arranged in line.

7. A conveyor according to any of the preceding claims, in which the conveyor is formed in two parts, comprising a first short conveyor which in use is arranged adjacent the slicing blade of the slicing machine, and a second conveyor downstream of the first conveyor, both conveyors having an independent drive and control means, the first short conveyor comprising the said generally flat slice receiving platform formed by toothed wheels.

8. A conveyor according to claim 7, in which the second downstream conveyor includes an upstream part which also comprises toothed wheels (2) .

9. A conveyor according to any of the preceding claims, in which the toothed wheels (2) are followed by a multi¬ element strip conveyor.

10. A conveyor according to claim 9 , when dependent upon claim 4, in which the multi-element strip conveyor is intercallated with the toothed wheels (2) on the downstream axle of the slice receiving platform.

11. A jump conveyor according to any one of the preceding claims, in which the or each conveyor is under the control of a programmed computer which is also fed with signals from the slicing machine to enable the operation of the jump conveyor to be coupled and synchronised with that of the slicing machine.