NZ194919A - Switching of overhead conveyor switch,switch actuated by runner - Google Patents

Description

19+911 NEW ZEALAND PATENTS ACT 1953 COMPLETE SPECIFICATION AFTER PROVISIONAL NO: 194 919 DATED: 11 September 198 0 SUBSTITUTION OF APPLICANT UMCE8 SECTION 24 IMPROVEMENTS IN OR RELATING TO SWITCHES 6r^ouf (JCQ WE, AUTOMATIC SYSTEMS RESEARCH LIMITED a New Zealand company having its registered office, c/o Barr Burgess & Stewart, 12th Floor, CML Centre, 157 Queen Street, Auckland, New Zealand, do hereby declare the invention for which we pray that a patent may be granted to us and the method by which it is to be performed, to be particularly described in and by the following statement: 1949 This invention relates to switches, and has particular application to the switching of conveyor rails. Conveyor rails, and in particular overhead monorail conveyors are used in a variety of applications to transport loads 5 supported by skids which slide on a conveyor rail. A typical example of this is the use of overhead monorail conveyors in freezing works for the transport of carcasses through the various processing operations.

Skids slide on the conveyor rail and may have a hook or other suspension means attached thereto from which a load ,\ may be suspended. The skids are generally moved by a pusher conveyor situated above the conveyor rail, and having a plurality of fingers extending downwardly from the pusher conveyor to move along the top or side of 15 the conveyor rail to push individual skids along the conveyor rail.

Hitherto, skids have been switched from one conveyor rail to another by means of air rams moving the switch rail between two or more positions. Such air rams have 20 been initiated by an operator operating a switch when a load is to be switched from one conveyor rail to another. Loads supported by the skids are often heavy and it is desirable to move and switch loads from a main rail to a variety of branch rails as quickly and 25 accurately as possible. 1&4919 Conventional switching operations suffer from disadvantages. If several air rams are operated off the same compressed air source at or about the same time, full pressure may not be available for a particular air ram and thus, it may fail to move a switch rail fully home. Thus, a switch rail may only move half way between, say, a main rail and a branch rail, and when a load is pushed onto the switch rail it will fall off the other end, instead of moving onto a branch rail.

In addition, the power requirements and lack of positive switching of conventional switch mechanisms renders them undesirable for use in automatic or electronically controlled switching operations.

It is an object of this invention to go someway in overcoming the abovementioned disadvantages in providing an improved switch mechanism, or which will at least provide the public with a useful choice.

In one aspect, the invention provides a switch mechanism for use with a pusher conveyor having at least one protruding finger, said mechanism including: a support; a movable switch rail pivotally connected to said support; guide means pivotally connected to said support, said guide means consisting of a guide channel mounted alongside said switch rail and pivotally connected to said support adjacent the pivot region of said switch rail; connection means for connecting the guide means to said switch rail, said connection means including a movable linkage capable of varying the distance between the non-pivot ends of the switch rail and the guide means; whereby in use, movement of said at least one protruding finger through said guide channel can be used to move the guide channel and hence the switch rail between selected positions. 1&4919 Other aspects of this invention, which should be considered in all its novel aspects, will become apparent from the following description, which is given by way of example only, with reference to the accompanying drawings, in which: Figure 1: illustrates an end elevation of a switch rail having a switch rail having a switch mechanism constructed in accordance with this invention.

Figure 2: illustrates the switch rail of Figure 1 in front elevation.

Figure 3: illustrates a top plan view of the switch rail in the straight through mode.

Figure 4: illustrates a top plan view of the switch rail in the (pre) switched position.

Figure 5: illustrates a top plan view of the switch rail in a post-switched mode.

The switch mechanism of this invention is applicable to various types of conveyor rails. For example, the switch rail may consist of a conventional rail hinged to a main rail, or it may consist of a resilient switch rail. - 194919 For example, a conveyor 10 may have main conveyor rail portions 10 and 11 separated by a switch rail 12. These rails 10 , 11 and 12 may be connected to a reinforcing member 13 running alongside the conveyor rail. The rails 10, 11 and 12 may additionally be supported by a support member 14, in the form of an inverted channel member having a flange 15 situated beneath the lower edge of the conveyor rails. The supporting channel member 14 can also serve as a stop for the switch rail 12, once it is moved back into the straight through position.

A branch rail 18 can be positioned alongside the main rail 11 as shown in Figures 3 to 5.

Skids 20 can be moved along the rails 10, 12 and 11 in the straight through mode or via the main rail 10 onto the switch rail 12 and thus onto the branch rail 18 in the switching mode. Such skids 20 may have portion 21 1949!-' fitting over the top of the rails and may also be provided with a hook 22 attached to the underside of the skid from which a load may be suspended.

Skids can be moved along the rails by means of a pusher 5 conveyor. A portion only of the pusher conveyor is illustrated in the drawings. Such a pusher conveyor may consist of a plurality of chain lengths 23 having a pushing face 24 on the underside thereof and a cam face 25 at the rear thereof. In addition, it is preferred that each 10 pusher element of the pusher conveyor is provided with a downwardly depending finger 26 positioned to one side of the main conveyor rails 10 and 11. As shown in Figure 3, the pusher face 24 may be curved to accommodate a skid as it moves along a curved path onto the switch 15 rail and thus moves away from the direction of travel of the pusher.

Guide means 30 is positioned alongside the switch rail 12 and preferably takes the form of a guide channel which is pivotally connected at 31 to the supporting 20 channel member 14. Preferably, the guide channel 30 consists of a channel member substantially U-shaped cross-section which is situated below the reinforcing member 13 and below a corresponding guide member 33. This guide member 33 preferably has an entrance portion 25 34 and exit portion 35 to assist in guiding a finger 1949 into alignment with the guide channel 30. The guide member 33 is conveniently attached to the support channel 14 by suitable studs 36.

Connection means 40 is provided to interconnect the 5 guide channel 30 with the switch rail 12. The connection means 40 preferably takes the form of a plate 41 which is attached to the movable end 42 of the switch blade 12. This is in turn connected to the guide means by a linkage 43 attached at 44 to the guide channel and 10 at 45 to the plate 41. Preferably, the linkage 43 is capable of being moved between and locked in one or other of two positions. Moving means 50 is provided to effect movement of the linkage 43. The components of the moving means, and their operation will be described 15 later.

Reference will now be made to Figures 3 to 5 and the interaction between the guide channel and the switch blade. Assuming that the switch mechanism is positioned in the straight through mode with the linkage 43 locked 20 in the position shown in Figure 3, then the guide channel 30 will be situated parallel to the conveyor rail .10, 12 and 11. Movement of a pusher element 23 and its associated finger 26 will cause a skid 20 to be pushed along the main conveyor rail 10, along conveyor 25 rail 12, and thus onto main conveyor rail 11. The finger 194 26 of the pusher will at the same time travel between the reinforcing member 13 and the guide member 33 and thus travel through the guide channel 30, as the finger 26 reaches into the guide channel 30 as shown in Figure 1.

Turning now to Figure 4, if the linkage 43 is switched to the position shown in Figure 4, with the guide channel 30 moved away from the reinforcing member 13, and a linkage 4 3 locked in the retracted position. This is referred to as the retracted position, as the distance between connection 44 and connection 45 is shorter than that in the extended position shown in Figure 3.

In this retracted position, the guide channel 30 is locked with respect to the plate 41, and hence with respect to the switch rail 12. As a skid 20 is pushed onto the switch rail 12 by means of a pusher 24 the pusher finger 26 will move into the end of guide channel 30. As the finger 26 moves from right to left of Figure 4, it will be constrained between the reinforcing member 13 and the guide member 33 and will thus cause the pivotally mounted guide channel 30 to move towards the reinforcing member 13, and thus the guide channel 30 will be biased towards the position parallel to the reinforcing member 13 and hence parallel to the path of the finger 26. As the guide channel 30 1549 J f is connected via linkage- 43 and plate 41 to the switch rail 12, the movement of the guide channel 30 will also cause the switch rail 12 to move into the position shown in Figure 5, In Figure 5, the switch rail is in the post-switched position with the pusher 24 having moved a skid 20 onto the branch rail 18. The finger 26 of the pusher is now at the end of the guide channel 30. As the switch rail 12 can be biased into the closed or straight through 10 position, shown in Figures 3 and 4, it will be apparent that when the finger 26 moves beyond the end of the guide channel 30, shortly after the position shown in Figure 5, then a restoring force applied to the switch rail 12 will cause the switch rail and the guide member to return to 15 the position shown in Figure 4. If it remains in this position, the movement of another skid being pushed by a pusher having a finger 26 will also cause the switch rail 12 to be moved into the switching position shown in Figure 5. If however, the linkage 43 is returned to the 20 position shown in Figure 3, then the movement of a pusher finger through the guide channel will enable a skid 20 to be pushed straight through and onto the main rail 11.

Movement of the guide channel 30 can be controlled by . various means. It will be appreciated that as the main 25 force required for moving the switch blade 12 is achieved ■ ' 19491 by linear movement of the pusher finger 26, the .switch can be controlled by a switching signal capable of moving the linkage 43 between two or more positions. Once the linkage 43 is locked in the switching position, then the switch blade 12 will be positively moved to the required switched position by movement of the pusher finger as a particular load is pushed onto the switch rail.

A preferred moving means 50 will now be described. The moving means 50 may consist of a rotary solenoid 51 mounted on plate 41. As shown in Figure 2, this may be mounted beneath the plate. The rotary solenoid may be supplied with an electrical signal to achieve movement of the linkage 43. For example, the shaft 52 of the rotary solenoid may be provided with an arm 54 to which is attached a chain 55. This chain 55, may be wound around a sprocket 56 with one end of the chain being attached to a suitable spring 57 anchored at 58 to the plate 41. The sprocket 56 is connected to a rotatable shaft 59 mounted on the plate 41. The sprocket and chains have been omitted from Figures 5 and 6 to illustrate the position of the linkage 43. Also attached to the shaft 59 is a lever 60 to which one end of a curved linkage 43 may be pivotally attached at 61.

Conveniently, the linkage 43 is curved as is shown in the drawings, to enable it to be locked in to over-centre 1949i :> positions. In the first over-centre position shown in Figure 3, the lever 60 is rotated through more than 180° from the position shown in Figure 5, in a clockwise direction until it is situated on the other side of the shaft 59 and thus the pivot point 61 is to the right of a line drawn between the centres of shaft 59 and connection point 44. Thus, the linkage 43 can be locked in an over-centre position.

When the rotary solenoid is operated, and its shaft 52 moves in an anti-clockwise direction to move the arm 54 and thus cause the chain 55 to rotate the sprocket 56 also in an anti-clockwise direction, the linkage 43 will be drawn around the shaft 59 until it is locked in the second over-centre position shown in Figures 4 and 5. In this position, any force on the guide channel 30 causing it to move in an anti-clockwise direction about pivot 31 will cause the linkage 43 to act as a solid connection between the channel member 30 and the plate 41 and hence draw the plate 41 in an anti-clockwise direction about pivot 31, moving the switch rail 12 from the position shown in Figure 4 to that shown in Figure 5.

In the arrangement shown in the drawings, the rotary solenoid 51 is mounted at one end of the plate 41 and is connected to shaft 45 by means of the arm 54 and the 1949!'? chain and sprocket. It will be appreciated that the rotary solenoid could be mounted directly on shaft 45 thereby eliminating the arm chain sprocket. At which case it is desirable to design the rotary solenoid so 5 as to be capable of sufficient rotational movement to move the linkage 43 between the two over-centre locking positions.

Although the moving means and the linkage have been described with reference to the rotational movement, it 10 , will be appreciated that other moving means can be used. It is however desirable (though not essential) to lock the guide means 30 in one of two positions so that movement of the pusher finger 26 will cause the switch rail 12 to be positively moved from one switching position 15 . to another. The two over-centre locking positions of the curved linkage 43 enables this to be readily achieved. By using a solenoid to control movement of the linkage 43 it is possible to use a .low energy signal to control the position of the guide means 30. This in turn allows the 20 movement of the pusher chain conveyor to effect movement of the switch rail of the pusher chain conveyor to effect movement of the switch rail. Consequently, it is possible to provide a plurality of switch mechanisms each controlled by an electrical signal, for example from a 25 computer or the like, so that the switch rails can be switched automatically. Such a switch mechanism could 1949 be operated directly from the outputs of a computer as i thesolenoids could be designed to be operated by low voltage signals. By providing a suitable bias on the switch rail 12 or on the shaft 45, the switch rail 12 5 can be designed to close if the solenoid fails to operate.

Instead of a curved linkage as illustrated, the linkage may consist of an arm connected to an eccentrically mounted bearing. This would enable external adjustable 10 stops to be provided alongside the arm to allow adjustment of the movement of the arm and hence vary the locking positions and thus movement of the switch rail.

If a multi-position switch rail is required, this could be achieved by using a stepping motor combined with 15 locking device, e.g. a movable detent. 1 Thus, by the preferred embodiment, a switch mechanism can be controlled by a low energy switching signal, and the switch can be designed to minimise the adverse effects of switch failure or incomplete switching.

Finally, it will be appreciated that various alterations or modifications may be made to the foregoing without departing for the scope of this invention, as exemplified by the following claims.

Claims (5)

WHAT WE CLAIM IS:

1. A switch mechanism for use with a pusher conveyor having at least one protruding finger, said mechanism including: a support; a movable switch rail pivotally connected to said support; guide means pivotally connected to said support, said guide means consisting of a guide channel mounted alongside said switch rail and pivotally connected to said support adjacent the pivot region of said switch rail; connection means for connecting the guide means to said switch rail, said connection means including a movable linkage capable of varying the distance between the non-pivot ends of the switch rail and the guide means; whereby in use, movement of said at least one protruding finger through said guide channel can be used to move the guide channel and hence the switch rail between selected positions.

2. A switch mechanism as claimed in claim 1, wherein the connection means includes a connection member connected to the non-pivot end of said switch rail, and also connected to said -adjustabl-a linkage which is in turn connected to said guide means. 3.

A switch mechanism as claim in claim 2, wherein said adjuatable linkage f* O V(KO tt_ is connected to switching means capable of switching said -a-djufltable-linkage between two or more positions.

A switch mechanism as claimed./in claim 3, wherein locking means is rwov©.fci_«_ provided to lock said adjustable linkage in any one of the switching positions.

5. A switch mechanism as claimed in claim 4, wherein said switching means consists of a rotary solenoid. A switch mechanism as claimed in any one of the preceding claims, substantially as herein described with reference to the accompanying drawngs. 7. A conveyor including a main rail interrupted by a switch rail, and having a branch rail adjacent one end of said switch rail so that movement of the switch rail can connect a portion of said main rail with either said branch rail or the remainder of the main rail, said switch rail being operable by a switch mechanism as claimed in any one of the preceding claims, skids capable of being moved along said rails, a pusher conveyor mounted alongside said main rail and having a plurality of pushers capable of engaging said skids, at least some of said pushers having fingers protruding therefrom so as to be capable of engaging said guide means. THORNTON ENGINEERING GROUP LIMITED By its Attorneys JAMES U PIPER & CO.