GB2049286A - Switching devices and switching arrangements - Google Patents

Abstract

A switching device consists of an elongate member such as a chain or belt including a plurality of elements 1 at least one of which can be moved laterally of the longitudinal axis of the member. The member is preferably flexible and endless and the lateral movement is, in one embodiment, achieved by the provision of tenons 3 and grooves 4 formed integrally with elements 1 and linking them together as a chain. When displaced laterally, an element 1 engages a switching member 5 when the elongate member is driven past the switching member 5 by e.g. rotation of a pinion 2. The device is suitable for use in a time switch when elements 1 act as trips to set a switching programme. Instead of each element 1 being displaceable laterally as a whole, it is possible for only a portion of each element 1 to be so displaceable. <IMAGE>

Description

SPECIFICATION Switching devices and switching arrangements The present invention relates to switching devices and switching arrangements.

Known time switches include trips which can be set in accordance with a predetermined switching programme to engage at given switching times with a switching member which may be electric.

In such time switches, it is frequently important that th switching time range, which usually covers twenty-four hours, should possess the highest possible resolution with regard to the setting of the switching times by the trips.

Due to the fact that the housing dimensions of time switches of this kind are frequently standardised, the switching discs which have a specified outer periphery and which carry the trips, are frequently too small in diameter to allow sufficiently finely graded programming whilst still providing the trips with a width which allows easy manual operation.

According to one asepct of the invention, there is provided a switching device comprising an elongate member provided with at least one element which is displaceable laterally of the longitudinal axis of the member.

In one embodiment, the or each said element is one of a plurality of elements linked together to form said elongate member.

Each element may be provided with guide means engaging in complementary guide means on an adjacent said element.

Preferably, said guide means is integral with its respective element.

Preferably, said guide means is arranged to guide at least one element when moved laterally of said longitudinal axis.

Preferably, said guide means and complementary guide means take the form of a tenon and groove respectively.

The guide means may have a cross-section which is circular, dove-tail shaped, T-shaped or capital omega-shaped.

In a further embodiment, said at least one element is a slidable element attached to said elongate member.

Preferably, the or each slidable element is provided with means for preventing detachment from said member.

Said elongate member is preferably flexible and may be endless.

Said elongate member may be a chain, a toothed belt or a perforated belt.

Preferably, the or each element is provided with locking means arranged to fix the position of the relevant element relative to said axis in a selected position.

Preferably, the or each element is of synthetic material.

According to a further aspect of the invention, there is provided a switch arrangement including: a switching device according to said one aspect; drive means for driving the switching device along a predetermined path parallel to its longitudinal axis; and a switching member positioned for actuation by the or each displaceable element when displaced laterally of said longitudinal axis.

In operation of the arrangement, the position along said path of the switching device may be dependent upon time.

Stationary guide means may be provided to guide at least one said element to a predetermined lateral displacement from said axis.

Preferably, said stationary guide means are carried by a housing of the arrangement or a carrier supported by the housing.

There may be provided a slide arranged for displacing at least one said element laterally of said.

axis.

Said slide may be carried by a housing of said arrangement.

Preferably, there is provided a drive pinion for driving said member.

The pitch diameter of said pinion may correspond to the pitch diameter of said elongate member.

Said switching member may be arranged to actuate an electrical device.

For a better understanding of the invention, and to show how the same may be carried into effect, reference will now be made, by way of example to the accompanying drawings, in which: Figure lisa cross-sectional view through a switching device; Figure2 is a plan view of a further switching device on a drive pinion whose periphery corresponds to that of the switching device; Figure 3 illustrates a time switch in an upright slide-in housing containing a switching device; Figure 4 is a cross-section through the time switch of Figure 3; and Figure 5 is a front view of the time switch of Figure 3.

Figure 1 illustrates a switching device formed as a chain whose links are teeth or elements 1 of synthetic material linked together by tenons 3 and complementary grooves 4. These elements 1 are shaped to engage with a drive pinion 2 in such manner that drive of the device is achieved with a relative small turning radius. It is also possible for the teeth of pinion 2 to engage directly with male bearing tenons 3 which are axially linked to the female grooves 4 in order to form the chain. In this case tenons 3 and the grooves 4 can possess a circular-cylindrical cross-section with relatively small spacing between two adjacent tenons.

The elements 1 can be displaced laterally of the chain longitudinal axis relative to one another and serve directly as sliding trips which can, when so displaced, operate a control lever 5 of a switching device (not shown in detail) in accordance with a switching programme. It will be apparent that this lateral sliding ability results from the cylindrical formation of tenons and grooves 3 and 4.

It is also possible that if necessary special contact cams can be applied to elements 1 if this provides better switching or control conditions for the device to be operated.

The elements 1 of a switching chain of this kind may be provided, preferably directly, with mutual locking means which are arranged in th region of the tenons 3 or grooves 4 for holding a set switching or programme position. Preferably, a minimum of two locking positions each elements 1 are provided laterally of one another. However it would be possible to provide an arbitrary number of additional locking positions if the chain had the appropriate width. instead of providing locking means directly on elements 1, it is also possible for a housing into which such a switching chain is installed, or a carrier provided in the housing, to be provided with groovelike guide elements which guide the elements 1 in the drive direction, said elements 1 being displaced laterally, in accordance with the programme.

Elements 1 which are designed in this manner and which directly engage with one another need not necessarily be constructed in the form of a switching chain which operates and is mounted on a plurality of pinions. It is possible for elements 1 which engage with each other in this way and which form a closed chain, to be mounted, as illustrated in Figure 2, on one single pinion 2 whose pitch diameter corresponds to that of the chain. As a result, it is possible to form a circular-cylindrical arrangement of trips which cannot be detached from one another, which serve to form a switching disc.

The male and female tenons 3 and grooves 4 which engage with one another and preferably are congruent with each other can have various crosssections in accordance with particular requirements, i.e. they can possess a dove-tailed, T-shaped or omega-shaped cross-section, the only requirement being that the cross-section is cylindrical i.e. of uniform cross-sectional shape across the width thereof.

Figure 3 illustrates a time switch arranged in an upright so-called slide-in housing 6 comprising a switching chain 7 which is directly assembled from individual elements 1. The switching chain 7 is mounted on pinions 2 and is driven by a synchro nous motor drive 8 via a special drive pinion 2' which engages with the switching chain 7. In this example, chain 7 can be manually moved along drive pinion 2' by means of a regulator wheel 9 in orderto programme the switching programme or in order to set the clock time. A coupling consisting of a toothed ratchet can be provided between the switching chain 7 and the drive means 8 in the region of the pinion 2'.

It can be seen that when the spacing between the elements or teeth 1 of the switching chain 7 is sufficiently small, an extremely small guide radius is achieved in the regions where the direction of chain 7 in the housing 6 is changed, whilst the chain 7 itself has a relatively large periphery. The switching chain 7 is arranged to operate a control lever 5 which in turn operates a switching device in the form of an electrical switching contact 10.

As shown in Figure 4, lateral guidance of elements 1 of the chain 7 to a tripping position can be effected by means of a specially designed guide element 11 on the pinions 2 or on a carrier. The programming of the elements 1, which serve as trips, of the switching chain 7 can take place by direct manual operation or by indirect manual operation via an appropriate slide 12 which can be arranged in the region of a window 13 provided on the front of the time switch, as shown in Figure 5. It may be provided that the spacing between the individual elements 1 ortheythem- selves can serve as time indication marks relative to a stationary reference point.

In a modification, it is also provided that a conventional chain or toothed belt or a perforated drive belt or some other endless drive means is used and laterally displaceable sliding elements are provided on the drive means to constitute trips, preferably arranged so as not to be detachable therefrom.

It is not essential that the elongate switching member-or chain is endless or that it is flexible, although preferably it is both endless and flexible.

It will be apparent that it is not essential for elements 1 of the chain 7 to be provided directly and integrally with bearing elements 3 and 4, although the preferred illustrated construction allows the formation of a switching chain of arbitrary length and extremely small guide radius. The elements 1 are displaceable laterally relative to one another in order to set a switching programme, and if necessary can be fixed in position in the relative programme position either directly or indirectly by notches or stationary guide elements, without thereby impairing the advance of the chain.

Although normally the chain will be driven as a function of time, e.g. a time switch, other possibilities will occur to those skilled in the art, e.g. it may be advanced by the occurrence of some external non regular event which is to be counted, such as the passage of traffic.

The individual elements of the switching chain can consist of synthetic plastics material or, in the case of special designs and applications, can be produced from a metallic material in a sintering process.

Advantageous features of the illustrated switching chain for use in conjunction with time switches are firstly that relatively small guide radii can be achieved thus allowing exploitation of the corners of a generally square or rectangular or upright rectan gular housing in order to provide the chain with a relatively large periphery and consequently a finely graded time resolution ofthe individual trips, and secondly that the elements of the chain can be integrated with the male and female bearing ele ments 3 and 4. Extremely economical production is achieved since only one component is required which can be assembled in the required quantity to form a switching chain.

Claims (27)

1. A switching device comprising an elongate member provided with at least one element which is displaceable laterally of the longitudinal axis of the member.

2. A device according to claim 1 wherein the or each said element is one of a plurality of elements linked together to form said elongate member.

3. A device according to claim 2 wherein each element is provided with guide means engaging in complementary guide means on an adjacent said element.

4. A device as claimed in claim 3, wherein each guide means is integral with its respective element.

5. A device according to claim 3 or 4 wherein said guide means is arranged to guide at least one element when moved laterally of said longitudinal axis.

6. A device according to claim 5 wherein said guide means and complementary guide means take the form of a tenon and groove respectively.

7. A device according to claim 6 wherein the guide means have a cross-section which is circular, dovetail shaped, T-shaped or capital omegashaped.

8. A device according to claim 1 wherein said at least one element is a slidable element attached to said elongate member.

9. A device according to claim 8 wherein the or each slidable element is provided with means for preventing detachment from said member.

10. A device according to any one of the preceding claims wherein said elongate member is flexible.

11. A device according to any one of the preceding claims wherein said elongate member is endless.

12. A device according to claim 10 or 11 when dependent on claim 8 or 9 wherein said elongate member is a chain, a toothed belt or a perforated belt.

13. A device as claimed in any one of the preceding claims wherein the or each element is provided with locking means arranged to fix the position of the relevant element relative to said axis in a selected position.

14. A device as claimed in any one of the preceding claims wherein the or each element is of synthetic material.

15. A switching device substantially as hereinbefore described with reference to the accompanying drawings.

16. A switch arrangement including: a switching device according to any one of the preceding claims; drive means for driving the switching device along a predetermined path parallel to its longitudinal axis; and a switching member positioned for actuation by the or each displaceable element when displaced laterally of said longitudinal axis.

17. An arrangement according to claim 16 wherein, in operation of the arrangement, the position along said path of the switching device is dependent upon time.

18. An arrangement according to claim 16 or 17 wherein stationary guide means are provided to guide at least one said element to a predetermined lateral displacement from said axis.

19. An arrangement according to claim 18 wherein said stationary guide means are carried by a housing of the arrangement or a carrier supported by the housing.

20. An arrangement according to any one of claims 16 to 19 wherein there is provided a slide arranged for displacing at least one said element laterally of said axis.

21. An arrangement according to claim 20 wherein said slide is carried by a housing of said arrangement.

22. An arrangement according to any one of claims 16 to 21 wherein there is provided a drive pinion for driving said member.

23. An arrangement according to claim 22 when dependent on claim 11 wherein the pitch diameter of said pinion corresponds to the pitch diameter of said elongate member.

24. A switch arrangement according to any one of claims 16 to 23 wherein said switching member is arranged to actuate an electrical device.

25. A switch arrangement substantially as hereinbefore described with reference to the accompanying drawings.

26. A switching chain comprising sliding trips which can be set in accordance with a switching programme and which, at a given switching time, engage with a switching device which may be electric, wherein teeth or elements of the switching chain, which consist of trips, are arranged so as to be axially displaceable in order to allow programming of said switching programme.

27. A switching chain comprising a chain, a toothed belt, a perforated drive belt or another endless drive means; and at least one axially displaceable sliding trip carried by the drive means preferably in a detachable manner.