GB2264277A

GB2264277A - Overhead conveyors.

Info

Publication number: GB2264277A
Application number: GB9203822A
Authority: GB
Inventors: Keith Edward Deacon; Michael Glyn Lesley Deacon
Original assignee: MIDLAND HANDLING EQUIPMENT LIM
Current assignee: MIDLAND HANDLING EQUIPMENT LIM
Priority date: 1992-02-22
Filing date: 1992-02-22
Publication date: 1993-08-25
Anticipated expiration: 2012-02-22
Also published as: GB9203822D0; GB2264277B

Abstract

An overhead conveyor, of the general kind that may be used to move goods through a workplace to create an automated or semi-automated production line, comprises a cyclic track 1 of generally rectangular section, housing an endless chain 2. The links of the chain are wheeled bogeys, the wheels of alternate bogeys being in the horizontal and vertical planes in an alternating sequence. Pendant workpiece carriers 15 extend in cantilever from some or all of the bogeys 2 whose wheels are in the vertical plane, through a continuous longitudinal slot 3 in a vertical side wall of the track 1. The conveyor of the invention is significantly cleaner in operation than conventional conveyors, avoiding oil spillage from the moving chain onto the floor area below. The use of the conveyor is therefore potentially extended to clean environments, such as retail premises or food processing plants, where previously aesthetics or hygiene laws had made the use of overhead conveyors inappropriate. <IMAGE>

Description

TITLE: Overhead Conveyors Field of the Invention The invention relates to overhead conveyors, of the kind that are used to move goods through a workplace to create an automated or semi-automated production line. The conveyors have, however, many other uses and applications and the scope of the invention is not limited by any of the applications given by way of example in this Specification.

Background Art Box track overhead conveyors are known in which an endless bearing chain is driven to move around a cyclic track. The track is rectangular, generally square, in section with a continuous longitudinal slot in its bottom face. The track is suspended around a workplace and may be all on the same level or may have inclined sections to move goods around the workplace on the same or different floor levels. The goods are carried on load-carrying pendants which hang from the chain down through the slot in the track. The chain comprises pairs of bogeys each pair comprising one bogey with wheels in the vehicle plane and one with wheels in the horizontal plane, connected to one another and to adjacent bogeys by universal joints.

Conventional overhead conveyor systems with the slot in the bottom wall have been driven from above. For example, a caterpillar drive with a continuously moving straight linear portion of its drive track has been arranged to engage with a series of pivoted and spring -loaded dogs which are biased upwardly through a short slot in the top wall of the track, so that by engagement with successive dogs the caterpillar drive moves the chain cyclically around its track. Alternatively a portion of the track may be arranged on an arcuate curve in the vertical plane, so that as the bogeys making up the chain traverse the dip of that curve, they are engaged from above by the teeth of a driving pinion located vertically above the track and rotating in the vertical plane so that its teeth extend through a slot in the top of the track into engagement with the bogeys.

Of the above two drive methods, the former is expensive to install because of the relatively high cost of the caterpillar drive unit, and the latter is sometimes disadvantageous because it requires a discrete dip in the overhead track so as to create a track portion which follows a curve corresponding to the radius of the driving pinion.

One disadvantage of known overhead conveyors is that they deposit oil and dirt into the worplace. The bearing chain has to be well oiled, and there is a tendency for the oil to be spilled in droplets along the path of the conveyor. This has a certain nuisance value but no more in many heavy industrial environments. However if such conveyors were specified for the food or pharmaceutical industry, their dirtiness would make them totally unacceptable.

The Invention It is an object of the invention to provide an overhead conveyor that does not deposit oil and dirt into the working environment to the extent that known conveyors do. It is a further object of the invention to provide such a conveyor that is capable of carrying the same workload as conventional overhead conveyors with box section track.

The invention comprises an overhead conveyor comprising a cyclic track of generally rectangular section housing an endless chain each link of which comprises a wheeled bogey, with the wheels of alternate bogeys being in alternately the vertical plane and the horizontal plane, wherein mounting bolts for pendant workpiece carriers extend in cantilever from some or all of the bogeys whose wheels are in the vertical plane, through a continuous longitudinal slot in a vertical side wall of the track.

Because the continuous slot for the mounting bolts is in a vertical side wall of the track, the conveyor becomes dramatically cleaner in use. The tendency to splash and drip oil from the slot is vastly reduced by having that slot in the side wall rather than the base of the track, but there are other unexpected and important advantages.

The drive for the chain can be greatly simplified and improved. Because in any cyclic track pattern the track must turn through a net 360" in the horizontal plane, it is relatively simple to drive the track at a convenient bend in the track, from a driving pinion in the horizontal plane extending through a longitudinal slot in the vertical side wall of the track opposite to the continuous longitudinal slot. The bend is preferably a 90" bend, when the track turns through a complete 90" around a radius matching that of the pinion.A full 90" turn provides extremely good contact with the pinion; the choice of drive position may be made to match an otherwise necessary bend in the track; and the disposition of the drive pinion in the horizontal plane makes the installation much less dependent on adequate ceiling or roof clearance than were the previously known conveyor installations.

DRAWINGS Figure 1 is a perspective view of a portion of an overhead conveyor according to the invention, with the chain shown only schematically.

Figure 2 is an axial section through the track and a chain of such a conveyor; Figure 3 is a vertical section taken along the line X-X of Figure 2; Figure 4 is a horizontal section taken along the line Y-Y of Figure 2; Figure 5 is a schematic illustration of one possible mounting for the track; and Figure 6 is a schematic illustration of a drive mechanism for the chain.

Figure 1 shows a track 1 and a conveyor chain 2 of an overhead conveyor according to the invention. The track 1 has a continuous open slot 3 formed through one vertical side wall, and extends in a cyclic path around a workplace or other site of use. The track path must be cyclic and the chain 2 must be continuous, but the track 1 may rise and fall to follow the contours of the workplace or site of use, and may for example traverse different floor levels of the workplace or site of use as different parts of the same path.

Figures 2 to 4 illustrate in greater detail the construction of the chain 2. It comprises a series of repeating identical units each comprising two wheeled bogeys 4 and 5. The bogeys are all interlinked by means of universal couplings 6. Each coupling 6 comprises a block pivotally connected to a bogey 4 by a vertical pivot pin 7 and to an adjacent bogey 5 by a horizontal pivot pin 8.

Each bogey 4 comprises a pair of double cranked plates 9 mounting three wheels 10. The wheels 10 are on a common vertical axis mid-way along the bogey 4. The top and bottom wheels 10a and lOc are mounted above and below respectively the double cranked plates 9 and are side bearing wheels which in use engage the insides of the vertical side walls of the track 1. The central wheel lOb is a drive wheel the function of which is described below. All three wheels 10 are preferably crowded race ball bearing wheels. They may be nylon covered or, for example for paint oven applications, may have bare metal rims.

Each bogey 5 comprises a pair of flat plates 11 between which is rotatably mounted a pair of wheels 12, on a common horizontal axis. Instead of a pair of wheels 12 one wheel, preferably of a width substantially filling the gap between flat plates 11 and on the same axis, may be used. The axis is a horizontal axis mid-way along the bogey 5. The wheels 12 are bearing wheels which take the load of articles being transported by the conveyor. As with the wheels 10, the wheels 12 are preferably crowded race ball bearing wheels. They may be nylon covered or may have bare metal rims.

Extending in cantilever from some at least of the bogeys 5 is a pair of mounting bolts 13. As illustrated, each mounting bolt has a screw-threaded end 13a, a relatively narrow portion 13b, a relatively wide portion 13c and a screw-threaded end 13d. The bolt 13 passes through an unthreaded hole in one of the flat plates 11 and is screw-threaded at 13a into a threaded hole in the other of the flat plates 11 until the shoulder between the portions 13b and 13c is brought into firm abutment with the respective plate 11. The portion 13d projects outwardly in cantilever through the open slot 3 of the track 1.Two nuts 14 may be screw-threaded onto the projecting portion 13d to secure in place a pendant mounting bracket 15 which is heavily cranked as shown in Figures 1 and 2 to bring its load carrying points 15' vertically beneath the centreline of the track 1 and beneath the bearing wheel or wheels 12.

If desired, the bolts 13 may be used singly and designed to pass through the axis of the wheels 12, so that each pendant mounting bracket 14 hangs vertically below the bearing wheel or wheels 12 even for non-horizontal portions of the track 1. Alternatively, the bolts 13 may be used in pairs but designed to pass through the horizontal pivotal axes of the pivot pins 8 so that the horizontal pivot pin function is taken by the bolts 13.

The plates 11 generally mask the slot 3 in the area of greatest potential oil splashing, around the bearing wheels 12, thus augmenting the cleanliness of the conveyor system.

Figure 5 shows a mounting bracket 16 for the track 1, for overhead fastening. Suitable brackets can readily be fabricated for mounting the track on walls, as long as they do not interfere with the passage of the pendant mounting brackets 15 and their associated loads.

Figure 6 illustrates a drive mechanism for the chain 2. A 90" curved portion of track 2 has the continuous slot 3 formed in the vertical wall on the outer radius of the curve. The opposite vertical wall, on the inner radius of the curve, has a corresponding slot formed in the curved portion only. A horizontally disposed pinion wheel 17 extends through the slot in that inner curved wall, and spaced teeth 18 of the wheel 17 engage the drive wheels lOb of the bogeys 4.

The pinion wheel 17 is driven by a combined electric motor and gearbox (not shown) preferably having a torque limiting overload device. The drive may be unidirectional or bidirectional.

The conveyor system has many advantages over conventional overhead conveyor systems, of which cleanliness is certainly the most important in a variety of specific fields such as the food and pharmaceutical industry, dirt-free and dust-free areas of high technology industry, and paint shops. The conveyor system is also of great benefit in less demanding workplaces where finished merchandise is present and has to be kept clean.

Claims

CLAIMS:

1. The invention comprises an overhead conveyor comprising a cyclic track of generally rectangular section housing an endless chain each link of which comprises a wheeled bogey, with the wheels of alternate bogeys being in alternately the vertical plane and the horizontal plane, wherein mounting bolts for pendant workpiece carriers extend in cantilever from some or all of the bogeys whose wheels are in the vertical plane, through a continuous longitudinal slot in a vertical side wall of the track.

2. An overhead conveyor according to claim 1, wherein the chain is driven at a bend in the track, from a driving pinion in the horizontal plane extending through a longitudinal slot in the vertical side wall of the track opposite to the continuous longitudinal slot.

3. A overhead conveyor according to claim 2, wherein the bend in the track is a 900 bend around a radius matching that of the pinion.

4. An overhead conveyor according to any preceding claim, wherein the- cyclic path of the track includes rising and falling portions.

5. An overhead conveyor according to any preceding claim, wherein the wheeled bogeys forming the chain are interlinked one to the next by means of universal couplings.

6. An overhead conveyor according to any preceding claim, wherein the bogeys whose wheels are in the vertical plane have those wheels mounted in pairs, each pair being on the same axis of rotation.

7. An overhead conveyor according to any preceding claim, wherein each bogey whose wheels are in the horizontal plane has its wheels mounted in sets of three, each set of three being rotatable about the same axis and including a pair of side bearing wheels which in use engage the insides of the vertical side walls of the track, and a central drive wheel through which the chain is driven.

8. An overhead conveyor substantially as described herein with reference to the drawings.