GB2128030A

GB2128030A - Electrical contact arrangement with bridging contact member

Info

Publication number: GB2128030A
Application number: GB08324250A
Authority: GB
Inventors: Joachim L Naimer
Original assignee: Individual
Current assignee: Individual
Priority date: 1982-09-10
Filing date: 1983-09-09
Publication date: 1984-04-18
Also published as: NL8302904A; DK409883A; BR8304911A; IT1168829B; FI833024L; DK409883D0; ZA836411B; JPS5981879A; BE897687A; FI833024A0; FR2533066A1; AU1840983A; SE8304605L; DE3329617A1; GB8324250D0; IT8353699V0; SE8304605D0; FI833024A7; IT8367934A0

Abstract

A movable, rigid, resiliently- mounted bridging contact member 2 carries contacts 5 and 6 which are separable from fixed contacts 7 and 8 preferably by the action of cam 12 on plunger 10 to lift the member 2 against the springs 3. The contacts 6 and 8 are domed to meet over a central region but, to give stability to the bridge member 2 about its longitudinal axis, the contact 5 is shaped to engage the contact 7 at two points spaced apart across the longitudinal axis. Thus the bridge member 2 has a triangular three- point support. <IMAGE>

Description

SPECIFICATION Contact arrangement The invention relates to a contact arrangement having a bridging contact member which is rigid or stiffperse and is resiliently supported when in the closed condition and opposing contacts which are advantageously fixedly arranged, for selectively closing and interrupting an electric circuit.

In such contact arrangements it was formerly usual to make ali four contacts identical and to provide each of them with a curved contact surface.

It has nevertheless become apparent that, especially at high current intensities, for which indeed contact arrangements with bridging contact members that are rigid or stiff perse have mainly been provided, this led to high frequency vibration and consequently to an increased burning away of the contacts as well as to the production of an unpleasant noise.

The object of the invention is to avoid these disadvantages of the known contact arrangements.

This is achieved according to the invention in that the bridging contact member, when in the closed condition is supported with its contacts at three triangularly disposed positions on the opposing contacts. In this way a reliable and stable support of the bridging contact member on the opposing contacts is ensured and thus oscillation of the bridging contact member about its longitudinal axis is prevented. As has become apparent during comparative tests, the production of noise with a contact arrangement according to the invention was substantially less than with a conventional contact arrangement with four identical curved contacts and the pitting of the contacts with a contact arrangement according to the invention was also substantially less.

In a preferred embodiment of the invention, it is proposed that one contact should have two raised parts which may, if desired, be stud-like and are arranged laterally of the longitudinal axis of the bridging contact member or laterally of the line interconnecting the two opposing contacts, while the remaining contacts are provided in known manner with a curved contact end surface so that the provision of additional contacts is unnecessary.

This advantage is also obtained when one of the contacts has a continuous groove extending in the direction of the longitudinal axis of the bridging contact member or in the direction of the line interconnecting the two opposing contacts, the depth of which groove is greater than the height of the spherical cup of the corresponding contact which is supported on the borders of the groove and is curved in known manner like the remaining contacts, the groove being, if desired, made V-shaped, and the bottom and borders of the groove preferably being rounded or having an arcuate cross-section. In each case a defined three-point support of the bridging contact member is ensured and the contacts which differ from the conventionally curved shape of contact can be made, in each case, from conventionally curved contacts by indenting the groove with the aid of a suitably shaped tool.

The invention will now be described in greater detail with reference to the drawing, in which: Figure 1 is a partial section through a switch with a bridging contact arrangement, Figure 2 is a side elevation of the bridging contact arrangement according to Figure 1, Figures 3 and 4 show a first constructional form of a contact for use in a contact arrangement according to the invention, Figures 5 and Gshowa second constructional form of a contact, Figures 7 and 8 show a contact, such as is fitted in the contact arrangement according to Figures 1 and 2,and Figures 9 and 10 show a further constructional form of contact for a bridging contact member according to the invention.

Figure 1 shows schematically a switch 1 with a contact arrangement having a bridging contact member 2. This bridging contact member 2 is supported by springs 3 with respect to the housing 4.

The bridging contact member 2 is located with its contacts 5,6 on the opposing contacts 7,8 which are rigidiy connected to the housing, the opposing contacts 7,8 which are rigidly connected to the housing being connected in each case by a terminal 9. The bridging contact member 2 is controlled by means of a plunger 10, one end of which is formed with a slot 11 in which the bridging contact member 2 is accommodated. This plunger 10 is in contact with a cam disk 12 which is mounted on the control shaft 13'.

In a conventional contact arrangement similar to Figures 1 and 2, each of the four contacts has a curved contact surface, so that the bridging contact member 2 is supported at only two points, as a result of which oscillation of the bridging contact member 2 which is rigid or stiff per se obviously occurs about its longitudinal axis due to current forces, which leads to an unpleasant production of noise and an increased burning away of the contacts.

Figures 3 and 4 show a contact 5' in which a cylinder is impressed into the contact surface so that a groove 13 is formed which extends over the whole of the contact 5'. The radius of this groove 13 is shorter than that of the curved surface of the contact 7' which cooperates with the contact 5', as can be seen from Figure 3. In this way it is ensured that the bridging contact member of a contact arrangement similar to that of Figure 1 or 2 in which the contact 4' is fitted is supported at three points. Moreover, it is immaterial at which of the four possible positions the said contact is fitted, the remaining contacts being curved and the groove 13 obviously extending in the direction of the longitudinal axis of the bridging contact member 2 or in the direction of the line interconnecting the two opposing contacts 7,8.

The constructional form according to Figures 3 and 4 only in that the groove 13 is formed in a substantially flat contact surface of the contact 5, whereas according to Figures 3 and 4 the groove 13 is formed in curved end surface, so that two parallel ribs 15 are produced which extend laterally of the diameter of the contact Sand against which the corresponding contact can be applied.

The constructional form according to Figures 5 and 6 also has a continous groove 13 which, however, unlike the constructional forms previously referred to, has a V-shaped cross-section. In this constructional form, the groove 13, which is rounded both at its base and also on its borders, extends.

widthwise as far as the circumferential edge of the contact 51. The depth of the groove 13 is moreover such that the corresponding contact, which is curved in the conventional manner, rests at two-points on the walls of the groove.

A further constructional form of a contact 52, which permits a two-point support, is shown in Figures 9 and 10. In this the contact 52 has two stud-like projections 16 which, in the contact arrangement according to Figure 1 or 2, are arranged laterally of the line interconnecting the middle points of the opposing contacts.

Basically, in a contact arrangement according to the invention, only one contact 5,5', 51,52 is employed, while the remaining three contacts are formed in the conventional way and have a curved contact surface. At the same time, it is essential that the contact zones of the opposing contact with the contact 5,5',51,52 should be arranged laterally of the centre line of the bridging contact member 2 as shown in Figure 2.

Claims

1. Contact arrangement having a bridging contact member, which is rigid or stiff perse and is resiliently supported when in the closed condition, and opposing contacts, which are advantageously fixedly arranged, for selectively closing and interrupting an electric circuit, characterised in that the bridging contact member (2), when in the closed condition, is supported with its contacts (5,6;5',5";51 52,53,54) at three triangularly disposed defined positions on the opposing contacts (7,8,71,72).

2. Contact arrangement according to claim 1, characterised in that one contact (5,52) has two raised parts (15,16) which may, if desired be stud-like and are arranged laterally ofthe longitudinal axis of the bridging contact member (2) or laterally of the line interconnecting the two opposing contacts (7,8), whereas the remaining contacts (6,7,8) are provided in known manner with a curved contact surface.

3. Contact arrangement according to claim 1, characterised in that one of the contacts (5',5",51) has a continuous groove (13) extending in the direction of the longitudinal axis of the bridging contact member (2) or in the direction of the line interconnecting the two opposing contacts(7,8), the depth of this groove being greater than the height of the spherical cup of the borders of the groove (13) and is curved like the remaining contacts.

4. Contact arrangement according to claim 3, characterised in that the groove (13) is made V-shaped, the bottom of the groove and the borders thereof being preferably rounded.

5. Contact arrangement according to claim 3, characterised in in that the groove (13) has an arcuate cross-section.

6. An electrical contact arrangement comprising a stiff or rigid bridging contact member which is resiliently biassed against opposing contacts when in the closed condition, wherein the contacts of the bridging contact member are supported at three points on the opposing contacts.

7. An electrical contact arrangement as claimed in claim 6 in which the bridging contact member has one contact which engages an opposing contact at a single point and another contact which engages an opposing contact at two points spaced apart across the longitudinal axis ofthe bridging contact member.