GB1601399A

GB1601399A - Withdrawable unit for switching cabinets and distribution apparatus

Info

Publication number: GB1601399A
Application number: GB1546378A
Authority: GB
Original assignee: Licentia Patent Verwaltungs GmbH; Licentia Oy
Current assignee: Licentia Patent Verwaltungs GmbH; Licentia Oy
Priority date: 1977-04-21
Filing date: 1978-04-19
Publication date: 1981-10-28
Also published as: DE2717691A1; NL7804050A; NL184818C; NL184818B; DE2717691C3; BE866085A; DE2717691B2

Description

(54) WITHDRAWABLE UNIT FOR SWITCHING CABINETS AND DISTRIBUTION APPARATUS (71) We, LICENTIA PATENT VERWAL- TUNGS G.m.b.H., of 1 Theodor-Stern-Kai, 6 Frankfurt/Main 70, Federal Republic of Germany, a German body corporate, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement:- The invention relates a withdrawable unti for switching cabinets or distribution apparatus which may, for example, have a test position in which control contacts are in engagement in which the main contacts are arranged displaceable on an insert independently thereof.

Arrangements of this type are known as can be gathered, for example, from German Auslegeschrift No. 1 765 300. The subject of this document is an insert which comprises a carriage and a frame arranged slidingly thereon on which insertion contacts as well as the electrical switching devices, safety mechanisms etc. are arranged. The arrangement is undertaken so that the withdrawable unit can be inserted into the cabinet or into the system and locked there yet the main contacts are only brought into engagement with the cooperating contacts thereafter.

Thus, it is possible to undertake function testing without the main contacts conducting any voltage. The dimensions both of the carriage and of the frame arranged on the carriage are selected so that the function testing can be carried out when the door is closed. In accordance with German Offenle gungsschrift No. 23 21 069 a withdrawable unit for electrical switching apparatus having insertion contacts is known moreover in which all of the components are arranged in rigid manner on the unit. This unit is provided with a locking device which permits locking both in the inserted position and in the test position. In the test position the unit is not completely inserted into the switching apparatus owing to the fixed arrangement of all of the components on the insert.

The invention seeks to provide a withdrawl unit such as that of the type described at the outset so that, with simple handling, the unit can be automatically fixed in the switching cabinet or in the distribution apparatus before function testing is possible and before the contacts are brought into connection with the voltage conducting cooperating contacts. Moreover, measures may be provided by means of which it is ensured that during the insertion process the switching devices are not switched on.

According to the invention, there is provided a withdrawable unit for electrical switching or distribution apparatus comprising a base, an adjusting screw device, contact means and a pin member engaging the thread of the screw device and being coupled to the contact means via slide member located on the base, the screw device being rotatable from outside the unit to move the contact means relative to the base into an inserted position, and means for retaining the unit in the apparatus comprising a circumferentially extending portion of the screw device which, as the contact means move towards its inserted position, is arranged to engage behind a fixed stop member of the apparatus.

Control contacts may be provided on the unit and the unit may have a position in which the control contacts are in engagement but the main contacts are out of engagement.

As soon as the unit is inserted into the cabinet or the apparatus and as soon as the screw device or helix is rotated, it arrives behind a fixed stop with a part of its periphery and thus fixes the unit in the cabinet or the system and during further rotation the main contacts can be inserted.

The attachment of the helix may be provided with grooves or cams and the shaft of the helix can have grooves or cams which serve to control auxiliary switches. The arrangement of the grooves on the attachment of the helix is undertaken so that an auxiliary switch switches on the control voltage if locking takes place with the switching cabinet and is switched off again after a short further rotation and causes further switching on if the main contacts are inserted into their cooperating contacts. As a result, it is ensured that the switching devices are not switched on by test circuits if the contacts are inserted.

Similarly outward movement of the contacts can only take place if the control voltage is disconnected and the switching devices themselves are disconnected. The main contacts are preferably connected by a track mounted in the base of the insert carrying the pin which cooperates with the helix. The end of the helix may be provided with an undercut into which a spring-loaded safety bolt of the door rests and locks the door as soon as the shaft is rotated out of its starting position.

The invention will now be described in greater detail. by way of example, with reference to the drawings. in which: Fig. I shows a withdrawable unit in accordance with the invention in side view and partially in section; Fig. 2 shows the unit in plan view. and Fig. 3 shows a helix connected to the attachment in a view from the front.

The withdrawable unit which is frame-like is designated 1 in the drawings. A screw device or helix 3 is arranged on the part of a frame designated 2 into the screwthreads 4 of which projects a pin 5 which is connected to an insertion contact 7 via a track 6. The helix 3 projects with its end 8 through a door to the outside and can be rotated from there in known manner with a lever. The helix is provided moreover with an attachment 9 over a part of its periphery said attachment being shown particularly in Fig. 3. Moreover, an auxiliary switch 10 is present which is fixed to an angle member 11 and rests with its actuating pin 12 on the attachment 9.

However, two grooves 13 and 14 are arranged in the attachment 9 into which the pin 12 slips with appropriate positioning of the disc. Grooves are also provided on the part 15 of the helix into which the plunger 16 of a switch 17 can slip in certain positions.

The track 6 is mounted in a bulge 18 of the unit.

In the position shown in Fig. I the unit can be inserted into a switching cabinet or a distribution apparatus. Thus control contacts (not shown) and output contacts (not shown) are connected automatically. The door can be closed and, after a rotation of the helix of approximately 10o, the auxiliary switch slips with its plunger 12 into the groove 13 on the attachment 9 and the control voltage is switched on by the auxiliary switch 10 and test switching of the individual devices are possible. With this slight rotation of the helix, a movement of the track 6 and the contact 7 connected therewith has not yet taken place in practice. However the attachment 9 with its edge 19 has been placed behind a fixed stop 20 so that the entire arrangement is locked within the cabinet or the apparatus.

After carrying out the test switching the helix can be rotated further. Thus the plunger 12 of the auxiliary circuit 10 is again forced out of the groove 13 and as a result the control voltage is again disconnected. The slide 6 with the contacts 7 is moved by the helix and the contacts 7 come into contact with cooperating contacts or direct with a bus bar (not shown). If the contact 7 are located sufficiently in engagement with the corresponding cooperating contacts or busbars, then the groove 14 of the attachment 9 reaches the region of the plunger 12 of the auxiliary switch 10 and the latter causes reconnection of the control voltage so that now it is possible to undertake switching under full load. The entire unit is locked by the engagement of the attachment 9 of the helix with the stop 20.In order that the door of the switching cabinet or the system cannot be opened during insertion and removal, and undercut 21 is provided at the end 8 of the helix 3 which undercut 21 cooperates with a spring-loaded safety bolt of the door and permits opening of the door only in the disconnected condition of the system. In order to lock the helix in certain positions. a locking spring 22 is provided which, in certain positions of the helix. locks into appropriate grooves.

WHAT WE CLAIM IS: 1. A withdrawable unit for electrical switching or distribution apparatus comprising a base, an adjusting screw device. contact means and a pin member engaging the thread of the screw device and being coupled to the contact means via a slide member located on the base, the screw device being rotatable from outside the unit to move the contact means relative to the base into an inserted position, and means for retaining the unit in the apparatus comprising a circumferentially extending portion of the screw device which, as the contact means move towards its inserted position, is arranged to engage behind a fixed stop member of the apparatus.

2. A unit according to Claim 1, and further comprising a switch having an actuating plunger, the circumferentially extending portion of the screw device having one or more grooves or cams which, during rotation of the screw device cooperates with the actuating plunger of the switch.

3. A unit according to Claim 2, wherein the switch is arranged to switch a control voltage.

4. A unit according to claim 2 or 3, wherein the grooves or cams are arranged so that upon an initial rotation of the screw device the switch is switched on, that after further rotation of the screw device the switch is switched off, and that after yet further rotation of the screw device the switch is switched on.

5. A unit according to claim 4, wherein the grooves and cams are arranged so that

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. on by test circuits if the contacts are inserted. Similarly outward movement of the contacts can only take place if the control voltage is disconnected and the switching devices themselves are disconnected. The main contacts are preferably connected by a track mounted in the base of the insert carrying the pin which cooperates with the helix. The end of the helix may be provided with an undercut into which a spring-loaded safety bolt of the door rests and locks the door as soon as the shaft is rotated out of its starting position. The invention will now be described in greater detail. by way of example, with reference to the drawings. in which: Fig. I shows a withdrawable unit in accordance with the invention in side view and partially in section; Fig. 2 shows the unit in plan view. and Fig. 3 shows a helix connected to the attachment in a view from the front. The withdrawable unit which is frame-like is designated 1 in the drawings. A screw device or helix 3 is arranged on the part of a frame designated 2 into the screwthreads 4 of which projects a pin 5 which is connected to an insertion contact 7 via a track 6. The helix 3 projects with its end 8 through a door to the outside and can be rotated from there in known manner with a lever. The helix is provided moreover with an attachment 9 over a part of its periphery said attachment being shown particularly in Fig. 3. Moreover, an auxiliary switch 10 is present which is fixed to an angle member 11 and rests with its actuating pin 12 on the attachment 9. However, two grooves 13 and 14 are arranged in the attachment 9 into which the pin 12 slips with appropriate positioning of the disc. Grooves are also provided on the part 15 of the helix into which the plunger 16 of a switch 17 can slip in certain positions. The track 6 is mounted in a bulge 18 of the unit. In the position shown in Fig. I the unit can be inserted into a switching cabinet or a distribution apparatus. Thus control contacts (not shown) and output contacts (not shown) are connected automatically. The door can be closed and, after a rotation of the helix of approximately 10o, the auxiliary switch slips with its plunger 12 into the groove 13 on the attachment 9 and the control voltage is switched on by the auxiliary switch 10 and test switching of the individual devices are possible. With this slight rotation of the helix, a movement of the track 6 and the contact 7 connected therewith has not yet taken place in practice. However the attachment 9 with its edge 19 has been placed behind a fixed stop 20 so that the entire arrangement is locked within the cabinet or the apparatus. After carrying out the test switching the helix can be rotated further. Thus the plunger 12 of the auxiliary circuit 10 is again forced out of the groove 13 and as a result the control voltage is again disconnected. The slide 6 with the contacts 7 is moved by the helix and the contacts 7 come into contact with cooperating contacts or direct with a bus bar (not shown). If the contact 7 are located sufficiently in engagement with the corresponding cooperating contacts or busbars, then the groove 14 of the attachment 9 reaches the region of the plunger 12 of the auxiliary switch 10 and the latter causes reconnection of the control voltage so that now it is possible to undertake switching under full load. The entire unit is locked by the engagement of the attachment 9 of the helix with the stop 20.In order that the door of the switching cabinet or the system cannot be opened during insertion and removal, and undercut 21 is provided at the end 8 of the helix 3 which undercut 21 cooperates with a spring-loaded safety bolt of the door and permits opening of the door only in the disconnected condition of the system. In order to lock the helix in certain positions. a locking spring 22 is provided which, in certain positions of the helix. locks into appropriate grooves. WHAT WE CLAIM IS:

1. A withdrawable unit for electrical switching or distribution apparatus comprising a base, an adjusting screw device. contact means and a pin member engaging the thread of the screw device and being coupled to the contact means via a slide member located on the base, the screw device being rotatable from outside the unit to move the contact means relative to the base into an inserted position, and means for retaining the unit in the apparatus comprising a circumferentially extending portion of the screw device which, as the contact means move towards its inserted position, is arranged to engage behind a fixed stop member of the apparatus.

the switch is not switched on until the unit has been retained in the apparatus by the circumferentially extending portion engaging behind the fixed stop member.

6. A unit according to claim 4 or 5, wherein the yet further rotation of the screw device is arranged to occur after the contact means has completed its movement towards its inserted position.

7. A unit according to any preceding claim wherein the screw device has a shaft which is provided with grooves or cams to control a, or a further switch.

8. A unit according to any preceding claim wherein the screw device has an end portion which is provided with an undercut which is arranged to receive the springloaded slide of a lock for a door of the apparatus.

9. A withdrawable unit substantially as herein described with reference to the accompanying drawings.

10. Electrical switching or distribution apparatus incorporating one or more withdrawable units according to any of the preceding claims.