Connected to an Electric System

TECHNICAL FIEkP

The present invention relates to a device for testing an objected connected to an electric system, and then particularly to a device for testing an object which is located out of the normal reach of a person.

The object referred to is normally a ceiling-fitted mounted light or lamp fitting and the device is intended either to check the earth connection of the lamp fitting and/or to ascertain the presence of voltage on the phase connection.

The inventive device is comprised of an extendable means, as aplurality of mutually telescopic sections, which when telescoped one into the other, folded or reeled up, have a length with enables the device to be kept in a standard tool-bag and which when extended, unfolded or reeled out is long enough to enable a person to test the otherwise unreachable object, without needing to take separate measures therefor. BACKGROUND ART

Belonging to the technical field of the present inven- tion are different devices which are intended to short- circuit or connect heavy-duty cables to earth.

Examples of the earlier state of the art are described and illustrated in publications CH-A5-59 256 and FR-A5-988 260.

The prior publication SE-B.1-84 05655-5, publication No. 450 974, teaches the use of a multi-section rod-like device for checking not-readily-reached parts of an electric system. The tip of the rod is suitably em- braced by a compressible helical spring which protects the tip, and the bottom end of the rod is provided with an aperture for the accommodation of an electric con¬ tact, for instance a banana contact pin.

The individual sections may be manufactured from an electrically-conductive material, thereby obtaining an electrically-conductive connection between the tip of the rod and the aperture or recess, irrespective of the length to which the rod is extended.

The publication also teaches the possibility of manufac¬ turing the sections from completely or partially non- conductive material, in which case the electric connec¬ tion between the rod tip and the aperture or recess is maintained by a flexible electric conductor, which is suitably incorporated in the rod.

DISCLOSURE OF THE INVENTION

TECHNICAL PROBLEMS

When studying the earlier state of the art, and particu¬ larly when studying the aforementioned Swedish patent publication, which teaches a rod for testing an object connected to an electric system and enabling an object to be tested which is out of normal reach of a person and which rod is extensible and comprises a plurality of mutually telescopic sections, it will be seen that a technical problem resides in the provision of a con- struction which is fully adapted to test said object and which has provided adjacent the handle of said device a

reel or like device which carries at least a long elec¬ trically conductive wire.

It will also be seen that a technical problem resides in the provision of a device of the aforesaid kind which is also provided with a unit capable of coacting with and/or accommodating means which function to establish an instantaneous testing result.

It will also be seen that a further technical problem is one of realizing the significance of providing a part, partially shaped to form a handle, which presents two mutually separated and mutually adjacent reel devices.

Another technical problem is one of realizing the sig¬ nificance of adapting a first of these reel devices for an electrically-conductive wire with one end of the wire attached to the tip of the narrowest of the mutually displaceable or mutually telescopic sections, and a second reel device to be adapted for an electrically- conductive wire with one end of said wire attached to an electric contact means, and to connect the other ends of the two wires to said means for establishing an instan¬ taneous testing result.

It will also be seen that another technical problem is one of realizing the significance of enabling the com¬ ponents from which said means is constructed to be enclosed in said handle-forming part, said components preferably being mounted on a printed circuit board.

It will also be seen that a technical problem resides in providing a device of the aforesaid kind in which said means has the form of a so-called buzzer when the device is used for testing earth connections, and has the form of a voltmeter when testing for voltage.

Another technical problem is one of realizing the signi¬ ficance of enclosing in a first reel-up device a spring means which will reel-up or reel-off automatically a length of electric cable which corresponds to the change in length caused by relative telescopic movement of the rod sections.

It will also be seen that a technical problem resides in realizing those advantages which are afforded when a second reel device is constructed to reel-up or reel-off a length of electrically-conductive, insulated wire corresponding to a chosen distance between said device and a selected reference point, namely a selected earth connection within easy reach of a person.

Another technical problem is one of realizing the sig¬ nificance of providing the handle-forming part with light-emitting diodes, display unit, switches and the like for ocular inspection purposes.

SOLUTION

The present invention is thus based on a device for testing an object connected to an electric system and enabling such an object which is located out of reach of a normal person to be checked or tested, said device comprising extendible member, . such as a plurality of mutually telescopic sections.

It is proposed in accordance with the invention that said members or said sections are arranged to coact with a handle-forming part which, in turn, is intended to coact with a reel device carrying a long electrically- conductive wire, and in that said handle-forming part is intended to coact with means necessary to establish an instantaneous test result.

According to preferred embodiments which lie within the scope of the inventive concept, the handle-forming part of the device is fitted with two reel devices, a first device for an electrically-conductive wire whose one end is attached to the tip of the narrowest of said mutually telescopic sections, and a second reel for an electri¬ cally-conductive wire whose one end is attached to an electric contact device or reference point, and in that the other ends of the two wires are connected to said means for establishing an immediate test result.

It is also proposed that the handle-forming part incor¬ porates the components necessary for said result indi¬ cating means, said components preferably being mounted on a printed circuit board.

The aforesaid means may have the form of a buzzer when testing an earth connection, and may have the form of a digital voltmeter when voltage testing.

It is also proposed that the first reel device encloses a spring device which functions to automatically reel-up or reel-off a length of electrically-conductive wire corresponding to a change in length of the mutually telescopic rod sections.

It is also proposed that the second reel device is adapted to reel-up or reel-off a length of electrically- conductive, insulated wire corresponding to a selected distance between said tet-result indicating means and a chosen reference point located within the reach of a person.

It is also proposed that the handle-forming part is provided with light-emitting diodes, digital display

unit, switches and the like, belonging to said means.

ADVANTAGES

Those advantages primarily afforded by the inventive device are that an object connected to an electric- system and located beyond the normal reach of a person can be tested by suitable adjustment to the length of an extensible device, for instance a device comprising a plurality of mutually telescopic sections, to a length corresponding to the distance to the object, thereby enabling the object to be tested without needing to take further measures, subsequent to unreeling a length of electrically-conductive, insulated wire corresponding to the distance to a selected reference point.

The primary characteristic features of the inventive device are set forth in the characterizing clause of the following Claim 1.

BRIEF DESCRIPTION OF THE DRAWING

An embodiment of a device at present preferred for testing an object connected to an electrical system in accordance with the present invention will now be de- scribed in more detail with reference to the accompany¬ ing drawing, in which

Figure 1 is a perspective view of a rod-like device comprising mutually telescopic sections, said

sections being shown partially extended; and Figure 2 is a schematic illustration of the application of the inventive device with an object located outside the normal reach of a person.

BEST MOPE OF CARRYING QVT THE INVENTION

The present invention thus relates to a device 1 for testing an object 2 connected to an electric system. As illustrated in Figure 2, the device can be used to check an object which lies outside the normal reach of a person, as exemplified by the person P who is unable to reach the lamp fitting 2 unaided, when standing on a floor 3.

The illustrated device comprises a plurality of mutually telescopic sections, in the illustrated case only two such sections la and lb, made of electrically insulated material, such as a reinforced plastic material.

The sections la and lb, and then particularly the sec¬ tion la, are intended to coact with a part lc which forms a handle 4.

The handle-forming part lc is intended to coact with at least one reel device 5 which accommodates a long elec¬ tric-ally-conductive wire or cable and which is intended to coact with an enclosed means 6 which functions to establish an instantaneous test result.

In the illustrated embodiment, the handle-forming part lc has two mutually adjacent reel devices 5a, 5b.

A first of these reel devices 5a is intended to accommo¬ date an electrically-conductive wire 7, with one end of

the wire attached to an electrically-conductive tip lb' of the narrowest of the mutually displaceable and elec¬ trically insulated sections, namely the section lb.

When the sections la and lb are made of an electrically- conductive material, it is normally unnecessary to include the wire 7 and one reel device 5a, since the requisite electrical connection can be effected through the electrically-conductive sections la and lb.

The second, ,5b, of said reel devices is intended to coact with an electrically-conductive, but electrically- insulated wire or cable 8, with one end 8a of said wire being attached to an electric contact device 9, in the form of a crocodile clip, and the other ends of respec¬ tive wires on respective reel devices are connected to said means 6.

The central region of the handle-forming part lc is configured to accommodate the components required to construct the aforesaid means 6 which establishes an instantaneous test result, these components preferably being mounted on a printed circuit board placed in a space referenced 6a in the drawing.

The means 6 may have the form of a so-called buzzer used to check earth connections, or may have the form of a digital voltmeter for checking voltages.

The digital voltmeter has a display unit 6b for estab¬ lishing instantaneous voltage digitally.

An advantage is afforded when the first reel device 5a encloses a known spring device (such as the type of spring device used with roller blind assemblies, without the latching means), said spring device functioning to

reel-off or reel-on a length of electrically-conductive wire 7 from or onto a reel bobbin included in said reel device, said length of wire 7 corresponding to the change in length of the mutually telescopic rod device la, lb.

The wire 7 will thus be constantly held stretched by the spring device, centrally through the tubular sections la, lb.

The second reel device 5b coacts with a spring device and latching means which function to reel-up or reel-off a length of electrically-conductive insulated wire 8 corresponding to the distance between the part lc and a chosen reference point 10 located within normal reach, this adapted length being best seen in Figure 2.

The central region of the handle-forming part lc is provided with light-emitting diodes 6c, 6d, the afore- βaid display unit 6b, and switches necessary for selec¬ tion of the desired testing mode, or the like, forming part of the aforesaid result indicating means.

It will be seen from Figure 1 that the second reel device 5, intended for the insulated wire 8, functions to reel-on and reel-off the wire 8, by appropriate manipulation of a handgrip 5b' which coacts with the reel or bobbin.

Although not shown in the Figure, the reel device 5b may be provided with friction-enhancing means or a latching mechanism which prevents the wire 8 from leaving the bobbin in an uncontrolled fashion.

When using the inventive device, the telescopic sections la and lb are extended to a length adapted to the dis-

tance from the object to be tested.

Although the maximum length of the inventive device is not restricted to any given value, a telescoped length of 1200 mm has been found ideal in practice.

Neither is the maximum length of the wire 8 limited to any given value, although a wire length of 20 has been found ideal in practice.

The invention is not restricted to the aforedescribed and illustrated exemplifying embodiments thereof, since these embodiments can be modified within the scope of the following Claims