GB2024130A - Rack drive conveyors - Google Patents

Abstract

A conveyor device comprising a plurality of load bearers (2) moveable along a path between a loading station and an unloading station, each bearer (2) having racks (12) provided one at each side to be engaged by drive gears (16) of the conveyor device which propel the bearer along the path. Each rack (12) is double-sided to be engaged either on its upper side or its lower side by the drive gear (16) and is formed by a strip bent into zig-zag or meander form. <IMAGE>

Description

SPECIFICATION Conveyor device This invention relates to a conveyor device comprising a plurality of load bearers moveable along a path between a loading station and an unloading station, a rack provided on each bearer, and drive gears spaced apart along said path to engage the rack of each bearer in order to move the bearer along at least part of said path.

A conveyor device of the above general type is known from United Kingdom Patent Specification No. 1,515,814. When a large number of bearers are used in a conveyor device of this type (travelling through a closed path having a loading station at which articles to be treated are taken-up and an unloading station at which treated articles can be discharged), a correspondingly large number of racks must be provided to enable the bearers to be moved along the path. The manufacture and assembly of these racks can be costly and complicated.

Accordingly, there is a need to provide for simplification in the construction of the racks. Also, the ability to provide greater selectivity in the positioning of the drive gears of the conveyor device would be advantageous.

According to the invention there is provided a conveyor device comprising a plurality of load bearers moveable along a path between a loading station and an unloading station, a rack provided on each bearer, and drive gears spaced apart along said path to engage the rack of each bearer in order to move the bearer along at least part of said path; in which each rack is double-sided to be engageable by drive gears located along the path and above the rack and by drive gears located along the path and below the rack.

Preferably, each double sided rack is formed by a strip bent into a zig-zag or meander form so as to provide a simple construction of rack. Also, by providing a double sided rack, greater flexibility is achieved in the design of the conveyor device and the path of movement of the bearers, in that drive gears can be positioned, as desired, to engage the upper or lower sides of the racks.

Conveniently, each rack is positioned between a respective one of the sides of the bearer and a protective shield spaced laterally from said side and extending parallel thereto. This provides a rigid and protective assembly for each rack.

To provide for movement of each bearer along the path, roller elements, such as wheels, may be mounted on the protective shields adjacent to the racks.

One embodiment of conveyor device according to the invention will now be described in detail, by way of example only, with reference to the accompanying drawings, in which: Figure 1 is a plan view of a treatment installation incorporating a conveyor device according to the invention; Figure 2 is a side view of the installation shown in Figure 1; Figure 3 is a detail view, to an enlarged scale, taken from Figure 1; Figure 4 is a perspective view of a bearer to be used in the conveyor device; Figure 5 is a side view, to an enlarged scale of one side of the bearer shown in Figure 4; and Figure 6 is a sectional view, to an enlarged scale, taken on the plane Vl in Figure 4.

The diagrammatic picture of a treatment installation shown in Figures 1 and 2 comprises a tower 1 arranged for the vertical upwardly directed transport of super imposed load bearers 2, carrying articles to be treated, such as for instance canned food. A similar kind of tower 3 is provided for a vertical downwardly directed movement of the bearers 2.

The tower 1 may be arranged, for example, as a pressure vessel within which the articles, standing on the bearers 2, are subjected to a heat treatment under pressure. In the tower 3 the articles on the bearers 2 may be subjected to a cooling operation.

The manner in which the vertical transport of the bearers takes place in the towers 1 and 3 does not form part of the present invention and will not be described in detail, but may conveniently be as described and illustrated in our United Kingdom Patent Specification No. 1,515,814.

Near the upper end of the towers 1 and 3 a connecting bridge is provided consisting of a closed conveying channel 4. A similar kind of connecting bridge is provided near the lower end of both towers, this latter bridge having the form of a closed channel or tunnel 5. The only difference in the channel 5 is that it has a feed opening 6, (adjacent a loading station) and a discharge opening (adjacent an unloading station) which are located directly opposite each other in the side walls of the tunnel 5.

The feed opening 6 is visible in Figure 2. In this manner the conveying path is constituted buy a closed circuit and the bearers 2 remain in the circuit.

By means of a feed conveyor 7 (Figure 1 ) and a discharge conveyor 8, the articles or materials to be treated can be supplied to a bearer 2a (Figure 2) lying in front of the feed opening 6.

By means of an appropriate device, the articles are supplied from the feed conveyor 7 onto a bearer 2 and are discharged again from this bearer onto the conveyor 8. Between the channels 4 and 5 and the towers 1 and 3 locks 9 are provided. These locks serve to keep the interior conditions within the tower 1 separated from the internal conditions within the tower 3. In the channel 4 the articles may eventually still be subjected to an intermediate treatment due to the fact that this channel 4 forms a closed unit between the towers 1 and 3.

One of the bearers 2 used in this installation is shown in Figure 4. The bearer consists mainly of a perforated plate 10 mounted in a rectangular frame 11. Along two opposite sides of the frame 11, racks 12 are provided, manufactured from strip material bent into a meander or zig-zag shape. The strip can be connected to the sides of the frame 11 by means of welding. The racks 12 each have a protective shield provided by an edge fillet 13 which is connected to the rack 12 by means of welding. In this manner a rack is obtained which is identical on both sides for a specific purpose which will be described in more detail below.

Upon the edge fillet 13 a number of roller elements, such as runner wheels 14 are mounted for guiding the bearer 2. It goes without saying that the bearers 2 can be moved easily over a rail 15 in the channel 4 by means of their runner wheels 14.

Driving means embodied as gear wheels 16 serve for the horizontal displacement of the bearers 2. Two axially spaced drive gear wheels 16 are mounted upon a common shaft 17. The distance between the gear wheels 16 upon a shaft 17 substantially corresponds with the width of the bearers, i.e. the distance between two racks 12 upon one bearer 2. The gear wheels 16 are interconnected through their shafts 17 and via worm gearboxes 18 and shafts 19 with universal couplings. Moreover these gear wheels 16 are connected to a common driving device 20.

It will be clear that when the bearers 2 within the tower 1 reach their uppermost position, their racks 12 will enter into engagement with the gear wheels 16a. These gear wheels will be rotated as soon as the lock 9 at the tower 1 is opened. By means of the rotation of the gear wheels 1 6a, bearer 2 will be discharged sidewardlythrough the lock 9 and will land on a rail 15. The further transport of the bearer 2 will be obtained by means of the gear wheels 16 within the channel 4. As soon as a bearer has gone through the lock 9, this lock is closed again. The bearer within the channel 4 which is further advanced by the gear wheels 16, will arrive in front of a lock 9 of the tower 3, which lock will then be opened.

The further transport of the bearer 2 is then taken over by a gear wheel 1 spa within the tower 3, until this bearer is lying completely within the means for the vertical transport within this tower. The rail 15 is interrupted at the location of the locks 9.

During the vertical downward transport of the bearers in the tower 3, the lowermost bearer must be discharged from said tower. In the lowermost position of the bearers 2, the rack 12 will engage a gear wheel 16b, (see Figure 3). The concerned bearer 2 will then be discharged from the tower 3 through the lock 9 towards the tunnel 5. The runner wheels 14 of this bearer 2 will then engage the rail 15 within this tunnel.

It will be noted that the shaft 17 of the gear wheels 16b lies under the conveyor path of the bearer 2. This is possible in that the strip forming the rack 12 has the same profile at its lower side and its upper side.

This means that the strip provides as it were a double sided rack, obtained by means of bending the strip material in a zig-zag or meander shaped form.

As soon as a bearer 2 has passed through the lock 9 and has arrived in the tunnel 5, the further transport is again taken over by a gear wheel 16, the shaft 17 of which is lying above the conveyor path.

At the feed opening 6 and the oppositely positioned discharge opening, the gear wheels 1 6c are provided with shafts 17 which again lie under the conveyor path. In this manner the bearers 2 can easily be loaded and unloaded without encountering any hindrance from the gear wheels 16.

After the unloading and reloading of the bearer 2a (Figure 2), it is conveyed towards the tower 1 after which the bearer is again brought into the correct position forthe vertical transport by means of the gear wheel 1 6b. In this manner a closed circuit is obtained, without the necessity of additional provi sions for bringing the gear wheels 16 into engage ment with the racks 12 of each bearer 2. The gear wheels 16 in the tunnel 5 and the gear wheels 1 6b and 1 6c are driven in a same manner as described with reference to the channel 4. The gear wheels 16 may be driven continuously or intermittently. The runner wheels 14 are journalled on axles 21 mounted upon the edge fillets 13.

It should be noted that the conveying device according to the present invention is not limited to the embodiment as hereinbefore described in con nection with the towers 1 and 3. The same conveying device may be used in different installations and structural alternations are possible, while still re maining within the scope of the invention as defined in the appended claims.

Claims (9)

1. A conveyor device comprising a plurality of load bearers moveable along a path between a loading station and an unloading station, a rack provided on each bearer, and drive gears spaced apart along said path to engage the rack of each bearer in order to move the bearer along at least part of said path; in which each rack is double-sided to be engageable by drive gears located along the path and above the rack and by drive gears located along the path and below the rack.

2. A conveyor device according to claim 1, in which each double sided rack is formed by a strip bent into zig-zag or meander form.

3. A conveyor device according to claim 2, in which each strip is located along one side of the corresponding bearer, and a protective shield extending parallel to said one side and spaced laterally therefrom is arranged alongside said strip.

4. A conveyor device according to claim 3, in which each bearer has a pair of said strips located one on each of two opposite sides of the bearer, with a corresponding protective shield adjacent thereto.

5, A conveyor device according to claim 4, in which each bearer has a number of roller elements for supporting the bearer during movement along said path, said roller elements being rotatably mounted on said protective shields.

6. A conveyor device according to any one of the preceding claims, in which said path is a closed path, and said loading and unloading stations are located substantially the same position along the length of said path.

7. A bearerfor use in a conveyor device which defines a path for the bearer between a loading and an unloading station, the bearer comprising a rectangularframe, a load-bearing plate mounted on said frame, and racks provided one at each of two opposite sides of the frame to be engaged by drive gears of the conveyor device to move the bearer along at least part of said path; in which each rack is double-sided to be engageable by drive gears located along said path and above the rack and by drive gears located along the path and below the rack; and in which each rack is formed by a strip bent into zig-zag or meander form, said strip being located between a corresponding side of the bearer and a protective shield spaced laterally from and extending parallel to said side.

8. A conveyor device according to claim 1 and substantially as hereinbefore described with reference to and as shown in the accompanying drawings.

9. A bearer according to claim 7 and substantially as herein before described with reference to, and as shown in the accompanying drawings.