WO1998034857A1 - Improved conveyor - Google Patents

Abstract

The present invention allows a path along which goods are being conveyed to be altered between a first and a second position. Transport of the goods is achieved by the use of a rope and pulley system (25, 26, 28), the path of the rope (25) altering as the conveyor alters between the first and the second position.

Description

Improved Conveyor

The present invention relates to a conveyor for conveying items, such as half bearings, between machine tools co-ordinated in production lines.

The manufacture of half bearings requires a number of featuring operations to a half cylindrical blank of pressed metal. These features are produced by the following operations. The features are 1) face and chamfer, 2) notch-mill notch, 3) oil groove, 4) pierce and countersink and 5) a second pierce and countersink. Not all half bearings required all of these features. For example, con rod half bearings have the first and second features and sometimes the fifth. A standard half bearing may have all of the first four features, but only optionally the fifth. Each feature is produced by a separate machine.

In the manufacture of a batch of bearings of a given diameter and length, each of the machines has to be set to operate for the given diameter. A change between the manufacture of batches of bearings having different dimensions requires all of the machines in a traditional straight linked line to be reset.

Since the machines are linked in straight lines, a bearing blank will enter the line at the beginning of the process and the completed bearing will exit at the end. If any of the machines are not correctly calibrated, only the incorrectly completed bearing will indicate this. In the event of an incorrect calibration, all of the component machines may need to be inspected to detect the error.

This also means that it takes two separate lines to run production, one line for con rod bearings comprising: 1) Face & Chamber

2) Notch Mill Notch

3) Pierce & Countersink

and a second line for main bearings comprising all five processes.

Further, if one machine in a line breaks down, the line cannot be used, leading to a loss of production in that line.

The present invention enables a single manufacturing cell having a number of machine tools to produce any kind of bearing having the five features of note. The present invention enables half bearings to be diverted between a first path and a second path.

According to the present invention, a workpiece conveyor comprising a first support plate, a second moveable support plate, the first and second plates defining a path for the movement of at least one workpiece, and transport means comprising a rope and pulley system for moving the at least one workpiece along said path, in which said second plate is moveable between a first position and a second position to alter the path.

The present invention allows for a bearing blank to be run through a manufacturing cell and diverted away from a particular stage of manufacture. Thus, a manufacturing cell incorporating the present invention can be configured such that only those operations required are performed. Also, if a machine has broken down, while the manufacturing cell cannot be used to manufacture a bearing having that process step, the cell may still usefully be employed in the manufacture of a bearing not having the particular process step by a suitable configuration of the manufacturing cell. The configuration, or route selection is controlled from a central control unit, and the relative divertor motions required are performer automatically to conform with the route selected by the operator. In short, the present invention allows for greater flexibility in the operation of a manufacturing cell.

The invention will now be described, by way of example only, with reference to the accompanying drawings, in which Figure 1 shows a schematic view of a manufacturing cell incorporating the present invention;

Figure 2 shows a perspective view of a conveyor according to the present invention in a first position;

Figure 3 shows a perspective view of the conveyor of Figure 2 in a second position;

Figure 4 shows a side view in partial section of the conveyor of Figure 2 in the first position;

Figure 5 shows a side view in partial section of the conveyor of Figure 2 in the second position; and

Figure 6 shows a detail of one end of the conveyor according to the present invention.

Referring to Figure 1 there is shown a schematic for a manufacturing cell for the manufacture of half bearings. A half bearing blank enters the manufacturing cell and is taken to a first workstation 1 where a face and chamfer operation is performed. The bearing is then conveyed along line 2 to a second workstation 3 where a notch-mill notch operation is performed. The half bearing is conveyed along line 4 to a divertor 5 where it may be conveyed either along line 6 to a third and a forth workstation 7, 8 where an oil groove operation and a pierce and countersink operation may be performed, or along an alternate line 9 to a second divertor 10. The second divertor is able to receive the half bearing from either the first line 6 or the alternate line 9. In either case the half bearing is then moved along line 11 to a third divertor 12. The third divertor can allow passage along either a first line 13 to a fifth workstation where a pierce and countersink operation can be performed, or along a separate line 15 to bypass this workstation. A fourth divertor 16 receives the half bearing from either the first line 13 or the separate line 15 to a final line 17 where the half bearing may exit the manufacturing cell. It can be seen that the divertor units are an integral part of the manufacturing cell.

A divertor unit according to the present invention is shown in Figures 2 to 6. Referring to Figures 2 and 4 there is shown a conveyor 20 according to the present invention in a first position The conveyor 20 is mounted on a base 21 A pair of pulleys 30, 31 are disposed horizontally for rotation about an axis of a spindle 33 A curved guide track 35 having a stop 36 at one end is provided on the base The track is disposed about a radius having the axis of spindle 33 as its centre The spindle 33 is held by an arm 37, extending from a stand 38 attached to the base 21

At a level with the upper pulley 30 there are located a first support plate 22 and a second support plate 24 The first support plate 22 is mounted in a fixed position in relation to the base The second support plate 24, as will be described may be moved about the axis of the spindle 33 At one end of each of the support plates there is located a vertically disposed pulley 26, 28 The upper surface of each pulley is of a similar elevation to an upper surface of a respective support plate Between one of the vertical pulleys 26 and the lower horizontal pulley 31 , there is located a set of three further pulleys 40, 41 , 42, two of which 40, 41 have a fixed axis, the third 42 having its axis of rotation being moveable toward and away from the other pulleys in the set

The second support plate 24, and one of the vertical pulleys 28 are held on a bracket 45 mounted on a plate 46 The plate 46 rests upon the guide truck 35 A guide flap 47, is supported from the second support plate and extends beyond the second support plate A railing 50 is provided on the base 21 on which to rest the guide plate 46, when the conveyor is in the first position The plate 46 is provided on each side with a stop 51 , 52 The base 21 is provided with an end stop 39 near to the railing 50

An endless rope 25 is passed over the pulley system as shown in the Figures The rope 25 passes through grooves (not shown) formed in the upper surface of the first and second support plates 22, 24 The grooves are such that an upper surface of the rope extends above the upper surface of the support plates In use, a bearing blank rests on the rope and a support plate, movement of the rope drawing the blank along the plate The third pulley 42 acts to keep the endless rope in tension

The rope 25 is driven by a drive motor 55 located near the first support plate 26 The upper pulley 30 has a rim having a substantially horizontal surface upon which in use the rope rests, and a substantially vertical surface against which in use the rope bears That is, the upper horizontal pulley 30 has no upper flange to allow the upper surface of the rope to stand proud of the pulley

The guide flap 47 is supported from the second support plate 24 by means of a toggle switch arrangement 29 (Figure 6) The pulley 28 is supported for rotation about its axis on bracket 45 The bracket also supports the second support plate 24 At one end of the second support plate there are two laterally spaced depending connectors 56, 57 The front most connector 57 has pivotally connected to it a first and a second link 59, 60 The first link 59 is connected to the guide flap 47 The second link 60 is fixed in relation to the first link 59 at one end A piston 58 joins the free end of the second link 60 to the rearmost connector 56 The piston 58 may be hydraulically or pneumatically actuated On actuation the piston increases in length causing the first and second links 59, 60 to rotate, in turn causing the guide flap 47 to be raised Deactivation of the piston will shorten the length of the piston allowing the guide flap 47 to be lowered

Also located on the plate 46 alongside the bracket 45 are location pins 66 These may also be hydraulically or pneumatically actuated The pins 66 may be moved to engage with or withdraw from suitable recesses provided in an adjacent machine

A corner plate 27 is pivotally supported along one edge on a stand (not shown) extending from the base 21 The pivoting edge of the corner plate 27 is on a level with the support plates

The operation of the conveyor will now be described with reference to the drawings In the first position, a motor drives the rope about a circuit defined by the pulleys A bearing is drawn over the first plate and over the second plate to the guide flap 47 As can be seen guide flap 47 is inclined slightly to the horizontal This allows the bearings to move down the guide flap under their own weight

In moving from a straight path (Figures 2 and 4) in a first position of the conveyor to a turned path (Figures 3 and 5) in a second position of the conveyor the following operations occur The drive 55 is stopped The piston 58 is actuated, guide flap 47 raised, and the location pins 66 housed on the plate 46 are caused to be withdrawn An air motor 39 located on the plate 46 is actuated, and acts to move the plate 46 along the guide track 35. This may be achieved by the motor 39 driving a gear wheel 44 which engages with the guide track 35 or by a rack and pinion system. Concurrently, the pulley 42 is allowed to rise. The location of the moveable pulley may conveniently be controlled by a rodless cylinder. The cylinder is arranged such that the stoke length matches the required change in position of the moveable pulley 42. The rodless cylinder may conveniently be connected to the air motor for simultaneous control of the movement of the pulley and the gear wheel.

It will be understood that other means of allowing the moveable pulley 42 to keep the tension in the endless rope 25 are possible. Thus, as the rope path extends about the horizontal pulleys 30, 31 , the rope path is shortened a corresponding amount by the raising of the moveable pulley 42.

At the end of the turning movement, the stop 51 on the plate 46 abuts the stop 36 on the base 21. Sensors in the stops may be used to determine when the turn is complete, though it will be understood that other detection means may be used. Once the turn is complete the location pins 66 are extended and may engage in suitable recesses in an adjoining piece of equipment with which the second support plate is aligned in the second position. On completion of the movement, the comer plate 27 is lowered to fill the gap between the first and second support plates, and the drive 55 is actuated. The corner plate does not interfere with the rope 25. An arc shaped cut out along an edge of the plate 27 allows the plate 27 to sit adjacent the upper pulley 30 and between the first and second support plates. On movement of the rope 25 around the upper pulley, a bearing blank from the first support plate is drawn on one side over the plate 27 and on the other side over the upper pulley 30 onto the second support plate 24.

The straightening of the bearing path is achieved in a similar manner. The drive 55 is stopped. The corner plate 27 is raised. The air motor 39 is actuated to drive the plate 46 back along the guide path until stop 52 on the plate 46 abuts the stop 39 on the base 21 , while the vertically moveable pulley 41 is lowered to keep the rope path of constant length. On completion of the movement of the plate 46, the drive 55 is actuated once again.

Claims

1. A workpiece conveyor comprising a first support plate, a second moveable support plate, the first and second plates defining a path for the movement of at least one workpiece, and transport means comprising a rope and pulley system for moving the at least one workpiece along said path, in which said second plate is moveable between a first position and a second position to alter the path.

2. A conveyor according to claim 1 , in which the first and the second support plates are provided with grooves, through which the rope passes.

3. A conveyor according to claim 1 or claim 2 in which the pulley system comprises a first and a second vertically arranged pulley at either end of the conveyor each associated with a respective support plate, a pair of horizontally arranged pulleys between the support plates, arranged orthogonally to the first and second vertically arranged pulleys and a set of three vertically arranged pulleys, in which one of the three pulleys is moveable with respect to the other two to maintain tension in the rope and pulley system.

4. A conveyor according to claim 3 in which a movement of the second support plate from the first to the second position, the second vertically disposed pulley moves about an axis defined by the first and second horizontally disposed pulleys, and the one of the set of three pulleys moves toward the other two of the set.

5. A conveyor according to claim 3 or claim 4 in which the upper of the two horizontally disposed pulleys is located between the two support plates and allows/permits the rope to extend above the plane of the pulley.

6. A conveyor according to claim 5 in which the upper pulley comprises a rim having only a substantially horizontal surface upon which the rope in use will rest, and a substantially vertical surface against which in use the rope will bear.

7. A conveyor according to any previous claim, in which a corner plate is arranged to be located between the first and the second support plate in the second position and to be located away from the support plates in the first position.

8. A conveyor substantially as described herein with reference to and as illustrated in Figures 2 to 6.

9. A manufacturing cell employing a plurality of conveyors according to any previous claim.