GB2276042A

GB2276042A - Contact probe for testing electrical equipment

Info

Publication number: GB2276042A
Application number: GB9304262A
Authority: GB
Inventors: Sui Kit Kwok
Original assignee: Centalic Tech Dev Ltd
Current assignee: Centalic Tech Dev Ltd
Priority date: 1993-03-03
Filing date: 1993-03-03
Publication date: 1994-09-14
Also published as: GB9304262D0

Abstract

A contact probe for use in testing equipment comprising a plunger member 12 which is mounted within a housing 16 wherein the plunger member is biassed by a biassing means 14 to extend outwardly from the housing a distance of from 3 to 3.9 mm. <IMAGE>

Description

IMPROVEMENTS IN AND RELATING TO CONTACT PROBES FOR USE IN ELECTRICAL TESTING EOUIPMENT This invention relates to spring contact probes used for electrical testing requirements in a variety of applications.

In particular, such probes are used in testing bare or loaded printed circuit boards, wire-wrapped back-planes, and other circuitries where a number of contact points must be accessed.

Prior art contact probes have a short life term due to their present arrangement.

It is an object of the invention to overcome this problem.

In accordance with the invention, a contact probe for use in testing equipment comprises a plunger member spring mounted within a housing characterised in that the plunger extends outwardly from the housing a distance from 3 to 3.9 mm.

Such a contact probe has the advantage of long life due to its specific dimensions and arrangement. In particular, the length of the exposed plunger member is shorter than any prior art arrangement, and since it is less exposed, it is less likely to be broken, damaged or the like, and thus has an expectedly longer life.

Suitably the stroke length of the plunger member is the same as in the prior art arrangement eventhough the plunger member is less exposed (suitably the stroke length is 1.3 mm).

Suitably the contact probe is mounted within a plunger receptacle mechanism, and most suitably the exterior housing of the contact probe extends outwardly from the outer end of the plunger receptacle mechanism a distance of 0.4 to 0.6 mm.

Suitably the diameter of the outer end of the plunger receptacle mechanism is between 0.65 and 0.74 mm.

The invention will now be described by way of example with reference to the accompanying drawings in which: Figure 1 shows a contact probe in accordance with the invention; Figure 2 shows a side view of the plunger receptacle mechanism used in association with the contact probe of Figure 1; and Figure 3 shows the contact probe of Figure 1 positioned within the plunger receptacle mechanism of Figure 2.

The contact probe 10 shown in Figure 1 comprises a pluger member 12 which is spring mounted (see 14) inside a housing member 16.

The contact probe shown in Figure 1 is positioned within a plunger receptacle mechanism 18 as shown in Figure 2, and in particular, as shown in Figure 3 with the housing member 16 of the contact probe slightly extending beyond the plunger receptacle mechanism.

The plunger member 12 of the contact probe is exposed to a limited degree compared to prior art, and in particular extends beyond the outer end of the contact probe's housing member 16 by a distance of 3 to 3.9 mm, and most preferably 3.4 mm.

In light of this relatively short exposed length, the plunger member is less prone to damage and the like, and thus has a much greater and unexpected life span than prior art contact probes.

The contact probe 10 when mounted in the plunger receptacle mechanism 18 is arranged such that the housing member 16 of the contact probe extends beyond the outer end of the plunger receptacle mechanism by a distance between 0.4 and 0.6 mm, and most preferably 0.5 mm.

The outer end 20 of the plunger receptacle mechanism suitably has a diameter of 0.65 to 0.74 mm, and most preferably 0.72 mm.

Other dimensions of the contact probe 10 and plunger receptacle mechanism 18 are as follows: a) The overall length of the contact probe 10 is preferably between 18 and 20 mm, and most preferably 19 mm.

b) The length of the outer end 20 of the plunger receptacle mechanism is preferably between 0.45 mm and 0.54 mm, and most preferably 0.5 mm.

c) The internal depth of the plunger receptacle mechanism 18 is preferably between 14.5 and 16 mm, and most preferably 15 mm.

d) The overall length of the plunger receptacle mechanism 18 is between 18.5 and 20 mm, and most preferably 19.2 mm.

The stroke length of the contact probe is 1.3 mm, and is standard with other different sized contact probes, which means the contact probe of the invention can be interchanged and used with existing different sized contact probes, thereby providing flexibility.

In conclusion, the length of the exposed plunger member 12 is shorter than in the prior art, whilst the length of the housing member 16 is longer, and this leads to the contact probe having a longer life time.

Claims

1. A contact probe for use in testing equipment comprising a plunger member which is mounted within a housing wherein the plunger member is biassed by a biassing means to extend outwardly from the housing a distance of from 3 to 3.9 mm.

2. A contact probe as claimed in claim 1 wherein the plunger member is biassed to extend outwardly from the housing a distance of 3.4 mm.

3. A contact probe as claimed in claim 1 or claim 2 wherein the plunger extends outwardly from the housing a distance of from 1.7 to 2.6 mm when the biassing means is in a fully compressed state.

4. A contact probe as claimed in any one of claims 1-3 wherein the contact probe is mounted in a contact probe receiving means.

5. A contact probe as claimed in claim 4, wherein the housing of the contact probe extends outwardly from the contact probe receiving means a distance of from 0.4 to 0.6 mm.

6. A contact probe substantially as herein described with reference to the accompanying drawings.