GB2206739A

GB2206739A - Switch box for use with varying designs of valves and actuators

Info

Publication number: GB2206739A
Application number: GB08814704A
Authority: GB
Inventors: Martin Richmond
Original assignee: Pegler and Louden Ltd
Current assignee: Pegler and Louden Ltd
Priority date: 1987-07-06
Filing date: 1988-06-21
Publication date: 1989-01-11
Anticipated expiration: 2008-06-21
Also published as: GB8715811D0; GB2206739B; GB8814704D0

Abstract

A switch box for use with varying designs of valves and actuators (e.g. pneumatic). So that the switch box (10) can be connected to a variety of different valves and actuators despite their having drive shaft ends of different sizes and/or different non-circular shapes, it has a coupling adaptor (30) for connection to any one of the range of actuator drive shafts, the coupling adaptor (30) being axially yieldable against spring loaded means (34) and being provided at an outer end with a depression formed by a plurality of successively smaller or differently shaped socket shapes. <IMAGE>

Description

Switch box for use with varying designs of valves and actuators.

The invention relates to a switch box for use with varying designs of valves and actuators.

There are available in industry a very wide range of valves and actuators for use in process control and the like. It is usual for such valves and actuators to be coupled to switch boxes by means of which the required movements of the actuators can be timed and adjusted in their stroke, or in response to the movement of which other functions can be triggered into operation. However, it is a particular problem that the valve spindles and the drive shafts of the actuators have varying designs of ends to which connections can be made. The invention has for its object to at least alleviate this problem.

According to the invention, there is provided a switch box adapted for fitment to any one of a range of different actuators which have drive shaft ends of different sizes and/or different noncircular shapes, the switch box having a coupling adaptor for connection to any one of the range of actuator drive shafts, said coupling adaptor being axially yieldable against spring loaded means and being provided at an outer end with a depression formed by a plurality of successively smaller socket shapes into an appropriate one of which any of the drive shaft ends of the range of actuators referred to can be fitted. The successively smaller socket shapes referred to may be constituted by successively smaller square shapes, successively smaller rectangular shapes or a combination of the two.The switch box may be adapted for fitment to any one of the range of different actuators by having a selection of bolt holes in a basal wall, said bolt holes being usable selectively.

In order that the invention may be fully understood and readily carried into effect, the same will now be described, by way of example only, with reference to the accompanying drawings, of which:- Figure 1 is a longitudinal section through a switch box embodying the invention, Figure 2 is a plan view of the switch box with a top cover removed, and Figure 3 is a perspective view of a drive stem part of the switch box.

Referring now to the drawings, the switch box there illustrated and generally indicated 10, is shown in Figure 1 to be mounted on a pneumatic actuator (shown in chain-dotted lines). The switch box has a rectangular hollow box part 12 a basal wall of which is provided with a plurality of bolt holes which can be used selectively to bolt the switch box to any one of a range of actuators with which the switch box is adapted to be used. Within the switch box there is located terminal block 14 and a pair of microswitches 16,16. Rotatably mounted alongside the pair of microswitches is a sensor arm 18 which carries adjustable contact members 20,20 for triggering the respective microswitches.The sensor arm is surmounted by an indicator plate 22 bearing the inscriptions "OPEN" and "CLOSED" one or other of which can be viewed through a window 24 in a removable top cover 26, depending upon the state of the switch box and the actuator on which it is mounted.

The sensor arm 18, which in fact is in the form of a disc with a depending skirt portion extending around only a part of its periphery, is carried by a stem 28. The stem 28 extends upwards from a coupling adaptor 30 which is rotatably mounted in a bearing 32, said coupling adaptor being slidably but non-rotatably mounted on the stem and being flanged at its upper end to prevent its escape through the aperture in the basal wall of the hollow box part in which it is located. A coil compression spring 34 is located on the stem 28 between the disc part of the sensor arm and the coupling adaptor 30.

Referring now to Figure 3, the coupling adaptor 30 which is viewed in inverted condition, is provided at its lower end with a depression generally indicated 36, this being formed by five adjoining and successively smaller socket shapes 38,40,42,44 and 46. The outer socket shape 38 is cylindrical. The next socket shape 40 is a square shape. The remaining shapes are elongate slots of different widths, the length of each slot being the same as the width of the square socket shape. The smallest elongate slot is provided with a pair of part circular shaped elongate key pieces 48 extending down its longer side walls as shown.

The arrangement is such that by virtue of the spring-loaded coupling adaptor just described, the switch box can very simply and easily be mounted on a wide range of actuators, that is to say actuators having output shaft ends of the different shapes and sizes commonly provided and projecting different lengths from the body of the actuators, their cross sectional shapes being complementary to the non-circular shapes 40,42,44 and 46 illustrated in Figure 3. It will be understood that a switch box of the kind described requires very little torque to drive it and that the very shallow driving connection provided between the drive shaft of the actuator and the appropriate socket shape of the coupling adaptor is not a problem.

The arrangement is of course such that a relatively small drive shaft end will cause relatively little axial displacement of the coupling adaptor whereas the relatively larger drive shaft ends will axially displace the coupling adaptor to a greater extent.

Various modifications may however be made and it will be understood that the spring-loaded coupling adaptor may have either a greater or lesser number of socket shapes constituting the depression 36 in its underside. Other socket shapes and sizes could be incorporated in the adjacent socket shapes which combine to form the depression 36 in the underside of the coupling adaptor.

Claims

CLAIMS:

1. A switch box adapted for fitment to any one of a range of different actuators which have drive shaft ends of different sizes and/or different noncircular shapes, the switch box having a cqupling adaptor for connection to any one of the range of actuator drive shafts, said coupling adaptor being axially yieldable against spring loaded means and being provided at an outer end with a depression formed by a plurality of successively smaller socket shapes into an appropriate one of which any of the drive shaft ends of the range of actuators referred to can be fitted.

2. A switch box according to claim 1, in which the successively smaller socket shapes referred to are constituted by successively smaller square shapes, successively smaller rectangular shapes or a combination of the two.

3. A switch box according to either one of the preceding claims, adapted for fitment to any one of the range of different actuators by having a selection of bolt holes in a basal wall, said bolt holes being usable selectively.

4. A switch box constructed, arranged and adapted to be used substantially as hereinbefore described with reference to and as illustrated by the accompanying drawings.