US3588392A

US3588392A - Rotary electrical switches and contact members therefor

Info

Publication number: US3588392A
Application number: US790332A
Authority: US
Inventors: John Anthony Cartwright
Original assignee: Individual
Current assignee: Individual
Priority date: 1968-12-31
Filing date: 1969-01-10
Publication date: 1971-06-28
Anticipated expiration: 1988-06-28
Also published as: GB1194970A

Abstract

A MULTIWAY ROTARY, SINGLE OR MULTIPOLE, SWITCH HAVING A MOVABLE CONTACT MEMBER ARRANGED TO PLACE ONE OF A NUMBER OF CONTACT ELEMENTS INTO ELECTRICAL COMMUNICATION WITH AT LEAST ONE CONDUCTOR ELEMENT, THE CONTACT MEMBER HAVING TWO CONTACT WIPERS, ONE OF SAID WIPERS HAVING A WIPING WIDTH GREATER THAN THE DISTANCE BETWEEN THE CONTACT PORTIONS OF ADJACENT CONTACT ELEMENTS WHILST THE OTHER WIPER HAS A WIDTH LESS THAN SAID DISTANCE SO THAT BY APPROPRIATE POSITIONING OF THE CONTACT MEMBER WITH RESPECT TO THE OTHER SWITCH COMPONENTS SUCH SWITCH MAY BE FORMED WITH ONE OF TWO PARTICULAR SWITCHING CHARACTERISTICS.

Description

United States Patent Appl. No. Filed Patented Assignee Priority ROTARY ELECTRICAL SWITCHES AND CONTACT MEMBERS THEREFOR 7 Claims, 6 Drawing Figs.

u.s. Cl 200/11, 200/166 Int. Cl uolh 1/06,

l-l0lh 19/58 rm oiSearch ..200/1l (A),

166 (CTS), 166(B8), 16

References Cited UNITED STATES PATENTS 1/1961 Zablocki et al 200/1 1(A)X Primary Examiner Robert K. Schaefer Assistant Examiner-L R. Scott Attorney- Kurt Kelman ABSTRACT: A multiway rotary, single or multipole, switch having a movable contact member arranged to place one of a number of contact elements into electrical communication with at least one conductor element, the contact member having two contact wipers, one of said wipers having a wiping width greater than the distance between the contact portions of adjacent contact elements whilst the other wiper has a width less than said distance so that by appropriate positioning of the contact member with respect to the other switch com ponents such switch may be formed with one of two particular switching characteristics.

ROTARY ELECTRICAL SWITCHES AND CONTACT MEMBERS THEREFOR This invention concerns rotary electrical switches and contact members therefor.

One object of this invention is to provide an electrical switch which may be fabricated from a plurality of components which may be assembled in more than one particular manner to provide the switch with more than one switching characteristic. For example an object of the invention is to provide a switch from a particular set of components which will have a make before break characteristic or a break" before make characteristic. A further object of this invention is to provide a switch which may be stacked with other switches to provide a multiway multibank switch, the switches of the bank either having a make" before break" characteristic, a break" before make characteristic or the bank being formed from switches having each of the characteristics.

Thus in accordance with one aspect of this invention there is provided a multiway rotary electrical switch comprising a body; a plurality of contact elements; at least one conductor element; a movable contact member arranged to place any one of said contact elements into electrical communication with a conductor element; said contact member carrying at least two contact wipers arranged, in at least certain positions of the contact member, respectively to engage one of the contact elements and a conductor element; one of said wipers having a contact or effective wiping width greater than the distance between the contact portions of adjacent contact ele ments whilst the other wiper has a width less than said distance.

Conveniently a multiplicity of contact elementsmay be provided the contact portions of the contact elements being supported in a common plane by a hollow switch body so as to be disposed radially thereof, the conductor element being located by the body in a plane spaced-apart from, but generally parallel to, the plane of the contact portions of said contact elements, said contact member being located between said two planes for rotation with the wipers thereof respectively biassed towards said planes.

in one embodiment, the body is of two-part construction, circular or polygonal in plan and having a central aperture therethrough, each of such parts carrying at least one projection which acts as a spacer to retain the parts in spaced parallelism with said apertures aligned on a common axis extending transversely to the planes of said parts, said projections serving also to locate and to retain said contact elements and conductor element in spaced parallelism within the body. The structure of the two parts forming the body in the vicinity of the apertures serve as bearings for a rotatable bush which carries said contact member.

Conveniently a first of the parts may comprise a disc provided on one peripheral surface with castellations and the contact elements are located between adjacent castellations with the contact portions thereof protruding above, or lying flush with, the castellations, such contact elements being retained in position by a projection carried by the other or second part. Such projection on the second part may advantageously be in the form of a peripheral flange or skirt extending transversely of the plane of a second disc forming the second part.

In preferred embodiments the peripheral flange or skirt on the second part is continuous but is provided with at least one rebate in which a corresponding abutment on the first part engages. Such rebate is provided to permit passage of a terminal portion of a conductor element and the abutment locks said conductor element in its operating position when the switch is assembled. The number of rebates, and the number of abutments, will depend on the number of conductor elements which are provided. For example, in a single or double pole switch one or two conductor elements will respectively be provided and a corresponding number of rebates and abutments will be provided.

Expediently where only a single contact member is provided the conductor element may comprise a ring of an electrically conductive material provided with one radially disposed coplanar tab constituting said terminal portion. However, where a pair of conductor elements are provided, each such element may comprise a half ring with a coplanar tab.

It will be understood that whilst in a single pole switch only one rotatable contact member would normally be provided, more than one contact member would be provided where necessary, for example, in a two pole switch. Thus according to one feature of this invention there is provided a single pole switch having a single contact member which operates in conjunction with a single conductor element. According to another feature of the invention there is provided a two-pole multiway switch including a pair of conductor elements each of which are acted upon respectively by a wiper of a corresponding contact member.

According to a further feature of the invention the or each said rotatable contact member may be formed from a single piece of electrically conductive material folded so that opposite end portions lie one above the other, such end portions constituting said wipers, one end portion or wiper having an effective wiping width greater than the effective wiping width of the other end portion or wiper. Naturally, however, the or each said contact member may be fabricated from more than one piece of material and the end portions may be provided with a precious metal contact surface or such end portions may comprise contact brushes which sweep the contact portions of the contact elements and the conductor element.

In one specific embodiment the rotatable contact member is stamped from a single element of a flat electrically conductive material shaped as a pair of Y-shaped parts lying end-to-end with the arms of the Y merging and the free end portions of the stems of the Y-shaped parts constituting said wipers, the contact member being formed by folding the stamping about its transverse centerline through, for example, an angle of ap proximately 120, so that in side elevation the contact member is substantially V-shaped, the free end portions of .the stems of the Y constituting said wipers being cranked inwardly so that their wiping surfaces lie substantially parallel to one another. Such particular embodiment of contact member is suitable for inclusion into a single pole switch where only one contact member is provided.

In one application such embodiment of contact member may be retained in position within the switch by a drive pin which lies between, and traverses, such contact member and also traverses said bush so that rotary movement of the bush with respect to the switch body, the contact elements and the conductor elements results in corresponding rotary movement of the contact member. in another embodiment however where two or more contact m3mbers are provided the bush may be provided with axially extending T-sectioned grooves into which the contact members may be snapped and located so that they rotate with said bush. In such an embodiment the contact member would preferably, however, be formed from a single element of conductive material in the general form of a pair of Ts positioned in end-to-end relationship with the cross pieces in contact, the free ends of the arms being provided to engage the walls of the T-sectioned grooves whilst the free end portions of the uprights of the Ts constitute the'wipers, the width of one wiper being greater than the width of the other wiper. In such an arrangement the double T element is folded so that the wipers lie in spaced parallelism one above the If desired said means may be associated with an actuating mechanism, and such actuating mechanism may comprise a sleeve carrying a body interlockable with the body of a switch, said sleeve guiding for rotary movement a rotatable shaft (adapted to be coupled to an operating knob at one of its ends) such rotatable shaft being releasably interconnected with said means. Expediently the bushes may be axially bored and said means may comprise a drive spindle of appropriate length located in such bores. In such an arrangement the rotatable shaft would be coupled to the spindle.

Very conveniently resilient biassing means may be incorporated into the actuating mechanism to define a plurality of particular angular positions of the drive shaft with respect to its body and the switch and such resilient biassing means may comprise a plurality of detents formed by balls located in apertures in a resilient plate such resilient plate biassing the balls into rebates positioned radially about the rotatable pin in the body of the actuating mechanism. Advantageously said actuating means incorporate stop means to limit the extent of rotary movement of said rotatable shaft with respect to the sleeve.

According to a second aspect of this invention there is provided for a switch in accordance with this invention, a contact member carrying at least two wipers, one of said wipers having an effective wiping width greater than that of the other wiper.

According to yet another aspect of this invention there is provided a plurality of components including a contact member having at least two wipers, one of said wipers having an effective wiping width greater than that of the other wiper, which may be assembled in two ways to provide an electrical switch which has either a make" before break" or a break" before make" characteristic.

In order that the invention may be more readily understood, and further features of this invention more readily appreciated, two embodiments of switch each suitable for stacking into a bank will now be described by way of example, and with reference to, the accompanying drawings in which:

FIG. I is an exploded vertical medial sectional view ofa first embodiment of switch in accordance with this invention, this switch being a two pole multiway switch;

FIG. 2 is a horizontal sectional view through the said first embodiment of switch, the line of section being shown as lI-II in FIG. 3;

FIG. 3 is a vertical section taken on the line Ill-III of FIG. 2;

FIG. 4 is a fragmentary perspective view of a plurality of contact elements, a pair of contact members each having a pair of wipers and a pair of conductor elements of the two pole switch shown in FIG. 1 to 3;

FIG. is a fragmentary exploded perspective view similar to FIG. 4 but showing the contact elements, a single rotatable contact member having a pair of wipers (such member being shown mounted on a rotatable bush) and a single conductor element of a second, alternative, embodiment of switch, this second embodiment being a single pole multiway switch; and

FIG. 6 is a fragmentary partly sectioned elevational view of a bank of switches in accordance with this invention shown stacked one upon the other and being operatively interconnected by a drive spindle passing axially therethrough, such spindle being operatively connected with a switch actuating mechanism, one of the switches of the stack being partly sectioned and being of the kind shown in detail in FIGS. 1 to 4 of the accompanying drawings.

In the first embodiment shown in FIGS. 1 to 4 and in FIG. 6 of the accompanying drawings the switch is formed from six basic components namely, a bush I adapted to support for rotary movement a pair of contact members 2 for engagement with contact elements 3 and conductor elements 4 all adapted to be housed within a body formed in two parts namely a first part 5 and a second part 6.

The first part 5 of the body comprises a flat circular disc 6 provided with a central circular aperture 7, the wall of this aperture 7 being stepped outwardly to provide a recess 8 surrounded by a ring of castellations 9 which define therebetween a plurality of rebates 10.

Protruding from the surface of the disc constituting the first part 5 of the body, diametrically opposite one another, are a pair of upstanding projections 11 whilst protruding from the opposite face of the disc are three equiangularly disposed feet 12. I

This first part 5 of the body is formed wholly from an electrically insulating material and advantageously is moulded from a plastics material as is the second part 6 of the body.

This second part 6 of the body comprises a circular disc 13 centrally apertured at 14, such disc 13 carrying around its periphery a continuous dependent skirt 15. This skirt 15 is provided with a pair of diametrically opposed rebates l6 having widths substantially equal to the widths of the projections 11 on the first part 5. The length of the skirt 15 is substantially equal to the height of the projection 11 and the diameters of the

discs

13 and 6 are such that the projections. 11 may be nested within the rebates 16, the arrangement being such that the skirt l5 lies around the periphery of the disc 6. Moulded integrally with, and equiangularly around, the said skirt 15 are a plurality of ribs 17.

Also formed from an electrically insulating material is the bush 1. This bush 1 is generally circular in plan, one end portion being provided with a circular protrusion 18 substantially equal in diameter to the aperture 14 whilst the opposite end is outwardly stepped at 19 to provide an annular seat 20 which is arranged to nest in the aperture 7 of the first body part and is located by the structure of the disc 6 defining such aperture 7. This bush 1 is provided with an axial bore 21, rectangular in cross section, which extends completely through the bush 1.

0n opposite sides of the bore 21 so as to be diametrically opposed to one another are a pair of T-sectioned rebates which extend parallel to the axis of the bore 21. These rebates which are designated 22 extend radially outwardly to the periphery of the bush.

Each of the rebates 22 is provided to accept and locate portions ofa respective one ofthe contact members 2.

The contact members 2 are formed from a stamping of an electrically conductive material such stamping being in the general form of a pair of TS positioned in end-to-end relationship with their cross pieces merging, the free ends of the arms (designated 23) being provided to lie within the rebates 22. The free ends of the uprights of the Ts constitute wipers 24 whilst the remainder of the uprights constitute resilient arms 25. The double T-shaped stamping is formed into a contact member 2 by folding the same along its transverse centerline so that it becomes substantially V-shaped in side elevation with the wipers 24 lying substantially one above the other, the free end portions constituting the wipers 24 being cranked inwardly so that when the contact member is in an operative position, such wipers 24 together present contact surfaces 26 which lie in spaced parallelism. To dissipate stresses the portion of the contact member in the region of the fold is rounded. It will be understood that the arms 25 of contact members 2 will provide a resilient support for the wipers 24 formed integrally therewith.

The wipers 24 of each member 2 are not of the same width and one wiper 24 has a width substantially greater than the other. This will be particularly apparent from FIG. 4 which also shows how the wipers are bowed slightly to produce smooth contact surfaces 26. It will also be seen from FIG. 4 that with the exception of the wiper width each contact member 2 is symmetrical and may be located within a rebate 22 in either one of two positions. The reason for this will become apparent from the following description.

In this first embodiment the contact elements 3 each comprise a length of electrically conductive material having a narrowed central neck 27 which carries, towards one end, a head constituting a terminal 28. This terminal 28 is apertured at 29. On its opposite end the neck 27 carries a contact portion 30. The neck has a width substantially equal to the width of the rebate 10 defined between each pair of castellations 9 and the contact elements are adapted to be located in such rebates 10' so that they are disposed radially about the aperture 7 in a plane substantially parallel to that of the disc 6 with the terminals 28 lying outside the periphery of the disc and with the contact portions 13 lying within the circle of castellations 9.

Referring now to the conductor elements 4 it will be apparent from FIG. 4 that such elements each comprise a flat half ring 31 carrying a coplanar tab 32 which in turn carries a head 33 apertured at 34, the apertured head 33 constituting a terminal. In this embodiment the half rings 31 are arranged so that they lie in a common plane with their tabs 32 lying away from one another. Each conductor element 4 is stamped from a sheet of an electrically conductive material and it should be understood that when in their operational position they are electrically isolated from one another.

The first embodiment of switch shown in FIGS. 1 to 4 of the accompanying drawings may be assembled as follows: Firstly a plurality of contact elements 3 are placed with their necks 27 in rebates provided between castellations 9 so that the contact portions 30 of the contact elements 3 lie in a ring within the castellations 9. The thickness of the contact elements 3 is slightly greater than the depth of the rebates 10 so that the contact portion 30 of each contact element lies slightly above the castellations 9, such portion 30 constituting a contact sur face which is to be wiped.

A pair of contact members 2 are introduced into the two rebates 22 provided in the bush 1 so that the arms 25 of the contact members 2 lie on the diameter of the bush. The bush 1 is then placed on the first body part 5 so that the annular seat thereof lies about the aperture 7 with the stepped portion 19 lying within the aperture 7. In this position the wipers 24 nearer the base of the rebates 22 lie adjacent the contact portions 30 of the contact elements 3.

The conductor elements 4 are then positioned within the second part 6 of the switch body so that the tab 32 of each conductor element 4 frictionally engages the side walls of the rebates 16. The second half 6 of the body, and the half rings 31 carried thereby, is placed over the first part 5 in which the contact elements 3, bush 1 and contact members 2 are located so that the peripheral skirt 16 engages the necks 27 of the contact elements 3 and so that such elements are located securely in the rebates 10 whilst the projections ll on the first part 5 enter the rebates 16 on the second part 6 and engage tabs 32 so that the conductor elements 4 are retained firmly in the second half.

lt will be understood from the above description that once the two

halves

5, 6 of the body are assembled with one another the contact elements 3 and conductor elements 4 will be firmly retained in spaced parallelism on opposite sides of the bush 1 and the contact members 2. The two

body halves

5, and 6 may be secured to one another in any desired manner but advantageously the

halves

5, 6 are bonded, adhered or otherwise secured together, so that the switch body is permanently sealed.

It will be understood that once the first and

second halves

5, 6 have been interconnected the contact members 2 will be compressed slightly so that the contact surfaces 26 of the wipers 24 will respectively engage the contact elements 3 and the conductor elements 4.

The wiping surfaces of the wipers 24 on each contact member 2 are, as stated hereinbefore, of different widths and in fact the widths are chosen so that one of each of the wiper contact surfaces 26 is less than the distance between adjacent contact portions 30 of the contact elements 3 whilst the other contact surface has a width greater than such distance between adjacent contact portions 30.

It will thus be understood that in dependence upon the manner in which the contact member is introduced into its rebate 22 the switch will have either a make" before "break" or a break" before "make" switching characteristic. In other words when the wider contact surface 26 is positioned towards the contact portions 30 the contact surface 26 will bridge, at least momentarily, adjacent contacts when the latter is being moved in response to rotary movement of the bush 1 from one contact portion 30 to a second contact portion 30. On the other hand when the narrower contact surface 26 is positioned adjacent the contact elements 3 the contact surface 26 will momentarily be disconnected from all contact portions 30 and will merely lie on the insulating castellations 9 which lie between the contact portions 30.

The above-described embodiment of switch is of a two pole five position switch and it will be understood that one pole may have a make before break" characteristic whilst the other pole may have break before make" characteristic. Alternatively both contact members 2 may be disposed in a similar fashion with respect to their contact elements 3 and conductor elements 4 so that both poles have the same switching characteristics.

The second embodiment of switch, partly shown in FIG. 5, is extremely similar to the switch already described above but this second embodiment of switch is a single pole multiway switch.

The second embodiment of switch has a two part body equivalent to the

parts

5, 6 but only one projection 11 is provided which seats in a single corresponding rebate 16. The reason for the use of only one projection 11 is that because the switch is a single pole switch only a single conductor element 4 is provided.

In this particular embodiment the conductor element 4 is a circular ring 40 provided with a coplanar tab 42 carrying a head 43 apertured at 44, the apertured head constituting a terminal. The first half 5 in this second embodiment is provided with castellations 9 and rebates 10 which accommodate contact elements 3. The contact elements 3 are identical to the contact elements described hereinbefore and have contact portions 30, necks 27, terminals 28 apertured at 29. These contact elements 3 seat within the rebates l0 and in a plane parallel to the plane of the conductor element 4. Between the two planes defined by the contact elements 3 and the conductor element 4 is a bush 1 which supports a single contact member 2. ln this embodiment however the bush 1 is of cylindrical form, one end of the cylinder being provided with a circular flange 45 which supports a web 46 which is transversely bored. This bush however is provided with an axially extending rectangular cross sectioned bore 21.

The transverse bore passing through the web 46 is provided to receive a drive pin 47 which transmits rotary movement of the bush 1 to the contact member 2, the contact member 2 being located firmly on the bush 1 by its interengagement with the web 46.

In this embodiment the contact member 2 is stamped from single element of a fiat electrically conductive sheet of material, the stamping being shaped as a pair of Y-shaped parts lying end-to-end with the arms of the Y merging and the free end portions of the stem of the Y-shaped parts constituting said wipers 24. The contact member is in fact formed by folding the stamping about its transverse centerline so that in side elevation the contact member is substantially V-shaped, the free end portions of the stems of the Y constituting said wipers 24 being cranked inwardly slightly so that their wiping surfaces 26 will lie (when the switch is assembled) substantially parallel to one another. As in the case of the first embodiment the contact member, in the vicinity of the position of the fold, is rounded. Furthermore the wiping surfaces 26 of this contact member 2 are of differing widths so that in dependence upon the relative position of the contact member 2 with the bush 1, the switching characteristic of the switch may be appropriately selected.

In both embodiments it will be appreciated that rotation of the bush will cause the wiper 24 lying adjacent the contact element to move from one contact element 3 to the next whilst the other wiper 24 lying adjacent a conductor element 4 will merely ride along such conductor element.

Naturally it is desirable to provide a stop to limit the amount of rotation of the bush with respect to the switch body but in the above described embodiments of switches such stop is incorporated into an actuating mechanism formed separately thereof. lt is to be understood, of course, that such stop could be incorporated into the switch itself if desired.

A typical switch actuating mechanism is depicted in F 10. 6.

FIG. 6 is a fragmentary, part diagrammatic and partly sectioned, elevational view showing a series of switches in accordance with this invention stacked together to form a bank of switches. For the sake of clarity, only the first embodiment of switch is shown in the bank but it will be appreciated that the bank maybe formed by stacking a plurality of switches in accordance with the first embodiment, or a series of switches in accordance with the second embodiment or a plurality of switches in accordance with both embodiments of switch described above.

In FIG. 6 the stacked switches constituting the bank is shown to have a drive spindle 48 extending completely through the bores 21 of the bushes 1. An upper end portion 49 of the spindle 48 extends into a slot 50 provided in an end portion of a rotatable shaft 51 located, for rotary movement, within the bore of a sleeve 52 such sleeve 52 being externally screw threaded at 53. This sleeve 52 is formed with a body 54 and such body 54 is coupled to the uppermost switch of the bank 55, the body 54 entering the recesses normally provided in the second part 6 of the switch for the reception of the feet 12 of an adjacent switch.

The body 54 is provided with a radially directed flange 56 which is coupled directly to the sleeve 52 and the under surface of the flange 56 (which lies within the body is provided with a ring of radially disposed rebates 57 which are spaced from one another and are adapted to be engaged by a plurality of balls 58 supported in rebates on a resilient ring movable with the shaft 51. A circlip 60 is provided on such shaft 51 to prevent axial movement thereof with respect to the sleeve 52 and such shaft 51 is provided with an annular recess 61 in which a sealing ring 62 seats, such ring 62 providing a dust seal between the sleeve 52 and such shaft 51. The resilient ring 59 is supported by a cylindrical boss 63 which also carries a radially disposed stop 64, the free end portion of this stop being arranged to abut a cooperating stop 65 on the internal wall of the body. The stop 64 extends through the shaft 51 so that it traverses the slot 50 and thus such stop 64 passes through the end portion 49 of the drive spindle 48 and transmits rotary movement of the shaft 51 to the spindle 48 and simultaneously limits the extent of rotational movement permitted of the shaft 51. The free end of the shaft 51 would normally carry an appropriate operating knob or lever not shown.

it will be understood that any rotary movement of the shaft 51 when transmitted to the spindle 48 will be further transmitted to the bushes 1 of the stacked switches forming the bank so that the wipers 24 will be moved accordingly;

The number of rebates 57 in the flange 56 will be chosen so as to be equal to the number of contact elements 3 and engagement of the balls 58 with such rebates will cause the actuating mechanism to have a snap action with an unstressed condition corresponding to the position of each of the contact elements 3 in each switch.

Whilst the switches of the bank may be releasably interconnected by means of appropriate clip means they may equally well be permanently secured to one another by means of an adhesive, the feet 12 interlocking with corresponding recesses to ensure correct alignment ofthe switches in the bank.

I claim:

1. A multiway rotary electrical switch comprising:

a body of two-part construction, first and second parts each having structure defining an aperture therethrough; a plurality ofcontact elements; at least one conductor element; a movable contact member arranged to place any one of said contact elements into electrical communication with a conductor element;

at least two contact wipers carried by said contact member arranged, in at least certain positions of the contact member, respectively to engage one of the contact ele ments and a conductor element, one of said wipers having a contact or effective wiping width greater than the distance between the contact portions of adjacent contact elements whilst the other wiper has a width less than said distance;

the contact portions of said contact elements being supported in a common plane by a hollow switch body so as to be disposed radially thereon, the conductor element being located by the body in a plane spaced-apart from, but generally parallel to, the plane of the contact portions of said contact elements, said contact member being located between said two planes for rotation with the wipers thereof respectively biassed towards said planes;

at least one projection carried by each of saidbody parts which acts as a spacer to retain the parts in spaced parallelism with said apertures aligned on a common axis extending transversely to the general planes of said parts, said projections serving also to locate and to retain said contact elements and conductor element in spaced paral- I lelism within the body; and

a rotatable bush which carries said contact member is provided, the structure of the two parts of the body defining the apertures serve as bearings for such bush. 2. A multiway rotary switch electrical switch comprising a body of two-part construction, first and second parts each having structure defining an aperture therethrough, the first body part comprising a disc, and a peripheral surface provided with castellations being provided on said disc;

a plurality of contact elements; at least one conductor element; a movable contact member arranged to place any one of said contact elements into electrical communication with a conductor element;

at least two contact wipers carried by said contact member arranged, in at least certain positions of the contact member, respectively to engage one of the contact elements and a conductor element, one of said wipers having a contact or effective wiping width greater than the distance between the contact portions of adjacent contact elements whilst the other wiper has a width less than said distance; the contact portions of said contact elements being supported in a common plane by a hollow switch body so as to be disposed radially thereon, the conductor element being located by the body in a plane spaced apart from, but generally parallel to, the plane of the contact portions of said contact elements, said contact member being located between said two planes for rotation with the wipers thereof respectively biassed towards said planes; at least one projection carried by each of said body parts which acts as a spacer to retain the parts in spaced parallelism with said apertures aligned on a common axis extending transversely to the general planes of said parts, said projections serving also to locate and to retain said contact elements and conductor element in spaced paral lelism within the body; and rebates defined between adjacent castellations locating the contact elements with the contact portions thereof protruding slightly above or lying substantially flush with the castellations, such contact elements being retained in position by the projection carried by the other or second part. r 3. A multiway rotary electrical switch comprising a body of two-part construction, first and second parts each having structure defining an aperture therethrough;

at least two contact wipers carried by said contact member arranged, in at least certain positions of the contact member, respectively to engage one of the contact elements and a conductor element, one of said wipers having a contact or effective wiping width greater than the distance between the contact portions of adjacent contact elements whilst'the other wiper has a width less than said distance;

at least one projection carried by each of said body parts which acts as a spacer to retain the parts in spaced parallelism with said apertures aligned on a common axis extending transversely to the general planes of said parts, said projections serving also to locate and to retain said contact elements and conductor element in spaced parallelism within the body, wherein such projection on the second of said parts retain said contact elements in position and comprises a peripheral flange or skirt extending transversely of the plane of a second disc forming the said second part.

4. A multiway rotary electrical switch, which comprises:

a body;

a plurality of contact elements;

at least one conductor element;

a movable contact member arranged to place any one of said contact elements into electrical communication with a conductor element;

at least two contact wipers carried by said contact member arranged, in at least certain positions of the contact member, respectively to engage one of the contact elements and a conductor element, one of said wipers having a contact or effective wiping width greater than the distance between the contact portions of adjacent contact elements, while the other wiper has a width less than said distance;

means, provided on said switch body, for interengaging and means for interconnecting a bank of switches so that all of said switches may be operated simultaneously; and

an actuating mechanism associated with said interconnecting means, said mechanism comprising a sleeve, a body carried by said sleeve and interlockable with the body of a switch, and a rotatable shaft guided for rotary movement by said sleeve, said rotatable shaft being coupled to said interconnecting means.

5. A switch according to claim 4, wherein resilient biassing means are incorporated into the actuating mechanism to bias the shaft into any one of a plurality of particular angular positions with respect to the mechanism body, such positions corresponding to the positions of the contact elements.

6. A switch according to claim 5, wherein a plurality of detents formed by balls located in apertures in a resilient plate constitute said resilient biassing means, such resilient plate biassing the balls into rebates positioned radially about the rotatable shaft in the body of the actuating mechanism.

7. A switch according to claim 6, wherein stop means are incorporated into the actuating means to limit the extent of rotary movement permitted by the rotatable shaft with respect to the sleeve.