GB2318460A - High voltage test probe - Google Patents

Abstract

A high voltage test probe comprises a rotatable grip (28) threadably engaging an axially moveable shell (34) coupled to jaws (46) for opening and closing the jaws. An operator with clumsy protective gloves can easily open and close the test probe jaws by rotation of the grip (28).

Description

.IGH VOLTAGE TEST PROBE This invention relates to a high voltage test probe, for example, for use with an oscilloscope, the probe comprising clamping jaws.

When using test probes in high voltage applications, the operator is required to wear protective gloves that make operation of the probe clumsy. This is particularly a problem with probes comprising a pair of clamping jaws for clipping to the device to be tested, such jaws typically being pivot mounted and open by gripping the jaws at one end between thumb and forefinger. Protective gloves make this operation clumsy and, additionally, it is difficult to position the clamping jaws in confined spaces.

It is an object of this invention to provide a test probe having clamping jaws that can be opened and closed easily and that enables easy access to confined areas of a device to be tested.

Objects have been achieved by providing a high voltage electrical test probe comprising a body extending along a longitudinal axis and having a casing enclosing electrical components, a test probe clamping jaw mounted pivotly to the body at a front end, and a jaw actuator for opening and closing jaw members of the clamping jaw for clamping to a conductor of a device to be tested, wherein the actuator comprises a grip rotatably mounted about the longitudinal axis to the body, and coupled axially to the jaw members via a coupling member such that rotation of the grip axially moves the coupling member thereby pivotly opening or closing the jaw.

Advantageously, opening and closing of the test probe jaws can be easily effected even with clumsy protective clothing. Furthermore, the invention enables operation of the jaws at a distance thereby enabling their access into confined volumes.

An embodiment of this invention will now be described by way of example with reference to the accompanying drawings, in which: Figure 1 is a partial cross-sectional longitudinal view through part of a test probe according to this invention; Figure 2 -s a similar view to figure 1 of the whole test probe; Figure 3 s a view in the direction of arrow 3 of figure 2; Figure g is a view in the direction of arrow 4 of figure 2; and Figure 5 -s a partial cross-sectional view of the probe in exploded -J- view, i.e. showing certain of the components disassembled.

Referring to the figures, a high voltage test probe 2 comprises a nain body 4 extending longitudinally along a longitudinal axis 6 and having a rear body portion 8 and a forward body portion 10 extending longitudinally therefrom.

The test probe 2 further comprises test probe clamping jaws 12 at a test probe or front end 14 of the body 4, and a jaw actuator 16 for opening and closing the jaws 12. The body 4 comprises an outer casing 18 that encloses electrical and electronic components within the body for processing signals from the test probe, and for radio transmission of signals to an oscilloscope. In other words, there are no leads interconnecti the test probe with the oscilloscope. A battery pack 20 is provided at a rear end of the body for supplying power to the electrical and electronic equipment. A grounding connection 22 also extends out of the body for providing a grcnd connection to the device to be tested. The ground lead 23 iS supported by a strain relief member 24 to a housing 27 of the battery pack 20. A rear cover 25 provide with resilient latching means 26 is mounted to the body casing 18 to close off a rear end of the test probe and batter pack.

he jaw actuator 16 comprises an outer insulate grip 28 rotatably mounted about the longitudinal axis - to the casing 8 and held axially thereto by interengaging shoulders and groove and protrusions meens 30,32 respectively. The grip externs over and along the casing from the rear bod portion to the front end 14 where the jaws 12 are situated. The actuator 16 further comprises an axially moveable shell 34 extenotng longitudinally and sandwiched between the 7rip 28 and forward portion 10 of the casing 18. The shell 34 comprises helical teeth 36 interengaging in a helical groove 38 of the grip, the threaded engagement adapted te axially displace the shell upon rotation of the grip. The shell 34 is a substantially cylindrical part closely surrounding the body forward portion 10.

the probe end 14, the axially moveable shell 34 is coupled to the jaws 12 by a coupling ring 40 engaging with its outer and inner diameters to grooves 42,44 in .he shell and fawns respectively. The jaws 12 comprise a pair of jaw members 46 each pivotly mounted at a pivot support 8 to the probe body at a longitudinal position proximate the longitudinal position of the coupling ring 40. Axial movement of the shell 34 thus actuates the separation or closing of the jaw members 46 at their free ends 50.

-- operator thus actuates the opening or closing of the jaws by holding the rear portion 8 of the body casing 18 with one hand, whilst rotating the grip 28 with the other for example. As the operator does not have to position h,- s hands prox~mate the probe end 14 in order to open or close the jaws, access of the jaws into a confined area is facilitated.

Furthernore the foward section 10 of the body can be provided as a small diameter elongate body for greater reach of the probe. The cylindrical shell 34 and front portion of the grin can be compactly mounted about the forward body portion 10. In addition, rotation cf the grip 28 is easy even with clumsy protective gloves. The grip 28 can be provided with radial flanges 52,53 acting as wheels to facilitate manipulation.

The abutment shoulder 30 is provided by a shoulder 54 of the casing 18 resulting frown the reduction in diameter of the front portion 10 of the l)uy with respect to the rear portion 8. The forward facing shoulder 30 provides large abutment surface to counteract the pressure generated during closing (clamping) of the jaw members 46 on a conductor, such that a secure and high clamping force can be achieved. The threaded engagement of the grip and axially moveable shell 34 also provides gearing enabling a high clamping force to be achieved.

Claims (7)

1. A high voltage electrical test probe comprising a body extending along a longitudinal axis and having a casing enclosing electrical components, a test probe clamping jaw pivotally mounted to the body at a front end, and a jaw actuator for opening and closing jaw members of the clamping jaw, said actuator comprising a grip rotatably mounted about the longitudinal axis of the body and coupled to the jaw members such that rotation of the grip axially moves said coupling thereby opening or closing the jaw.

2. The probe of claim 1 wherein the grip is coupled by a thread to an axially movable shell which is coupled to the jaw members, the grip being axially retained on the body by interengaging shoulder members.

3. The probe of claim 2 wherein the shell is substantially cylindrical.

4. the probe of any one of the preceding claims wherein pivot supports of the jaw members~are disposed in an axial position similar to the axial position of a coupling member coupling the grip to the jaw members.

5. The probe of any one of the claims 2 to 4 wherein the interengaging shoulder members comprise a stepped reduction in diameter of the body casing from a rear portion to a front portion, thereby forming a casing shoulder facing the front end against which a complementary shoulder of the grip abuts.

6. The probe of any one of the preceding claims wherein a front portion of the body and grip extending rearwardly from the jaw is elongate and substantially cylindrical.

7. A high voltage electrical test probe constructed and adapted to operate substantially as hereinbefore described with reference to the accompanying drawings.