GB2157499A

GB2157499A - Electrical switch.

Info

Publication number: GB2157499A
Application number: GB08509401A
Authority: GB
Inventors: Rolf Goehle; Erwin Muders
Original assignee: Brown Boveri und Cie AG Germany; BBC Brown Boveri France SA
Current assignee: BBC Brown Boveri AG Germany; BBC Brown Boveri France SA
Priority date: 1984-04-12
Filing date: 1985-04-12
Publication date: 1985-10-23
Also published as: GB2157499B; AU4098885A; DE3413808A1; NZ211781A; SG5389G; EP0158241B1; IN164944B; EP0158241A2; DE3581821D1; GB8509401D0; EP0158241A3

Description

SPECIFICATiON Electrical switch The invention relates to an electrical switch with a contact position having a fixed and a movable contact member and with an electromagnetic and/or thermal trip device, the said contact position being associated with an arc extinguishing device.

Electrical automatic cut-out devices whose magnetic trip mechanism or circuit breaker is a socalled tilting armature trip mechanism have the problem of converting the rotary movement of the armature to the rotary movement of the movable contact lever, particularly with respect to the object of quickly opening the contact position in order to achieve a current limiting. In a known switch the rapid opening of the contact position is effected by the tilting armature acting on a push rod guided in a displaceable manner parallel to the mid axis of the magnetic core, whereby the push rod strikes the contact lever when the tilting armature attracts. This type of construction is expensive since the push rod guidance has to be designed very accurately.

The principal patent (P 3242 062.5) discloses a suitable solution to this problem. However, this solution involves a switch with two contact positions separated by a wall, wherein both positions should be opened roughly simultaneously.

The object of the invention is to realise the solution disclosed in the principal patentforthe rapid contact position separation also in the case of a switch with one contact position.

This objective is achieved in accordance with the invention if the magnetic armature acts, via a rotary lever disengageable in the switch off mode, on the movable contact to open the latter, in such a way that on rotation of the magnetic armature designed as a tilting armature, the rotary lever is also rotated and strikes a contact lever bearing the movable contact member roughly in the direction of the opening movement and roughly vertically with respect to the extension of the contact lever.

By virtue of the arrangement of the rotary lever and the engagement or 'latching' position on the latter, after tripping by means of the rotatable rotary lever in the opening position of the contact lever the said contact lever is rapidly struck and the contact position is rapidly opened, thereby producing a current limiting.

A lug situated in the movement region of the tilting armature is preferably formed on the rotary lever or on the latch lever, and a latch position is also provided on the rotary lever which serves to engage the contact lever of the first contact position.

Further advantageous embodiments and improvements of the invention are disclosed in the other subclaims.

The invention as well as further advantageous modifications and improvements thereof and further advantages are described and illustrated in more detail by means of one embodiment of the invention and with the aid of the drawing.

The single figure of the drawing shows a view of a switch in accordance with the invention.

The switch comprises a housing 10 of a shell-type construction, and has two housing shells (not shown in more detail). The housing includes in its lower region a recess 12 to enable the switch mechanism to be snap-fitted on a U-shaped assembly bar in an installation compartment.

The switch mechanism comprises a contact position 20 formed from a movable contact member 24 and a fixed contact member 28.

A tilting armature system 32 with a yoke 33, coil 34 and a magnetic core 35 is also provided. The magnetic core co-operates with a tilting armature 104 one of whose ends is mounted at 37 on an arm 100 of the yoke 33 running parallel to the magnetic core 35.

The switch comprises a contact lever 40 on which the movable contact member 24 is formed.

A switch lever 45 is mounted in the housing 10 on a shaft 44, and a rod 46 is coupled to the lever eccentrically with respect to the shaft 44 and connected to the contact lever 40 via a shaft 48 passing through an eyelet 110.

A tension spring 50 which urges the contact lever in the 'open' direction acts on the said contact lever 40.

As can be seen from the Figure, the yoke 33 is essentially Z-shaped and has an arm 100 running parallel to the mid axis of the magnetic core 35 which transforms into an L-shaped arm 101 in which an adjustment screw 102 engages. A nut can also be provided in the region of the arm 101 into which the adjustment screw of the arm 101 can be screwed home. The nut would be loose with respect to the yoke but would be fixed in the housing so that the adjustment screw does not rotate when the nut is tightened. The vertically aligned arm 100 is extended in the form of a holding angle piece 103 whose other free arm serves to retain a thermostatic bimetal strip 60. The tip of the adjustment screw 102 presses on the inner surface of this arm with the thermostatic bimental strip 60, by which means the tripping can be adjusted for an overload current.

Atilting armature 104 is mounted on the vertical section 100 of the yoke 33 and cooperates with a latch engagament lever 105 formed as a rotary lever. The tilting armature 104 acts directly on a lug 106 on the latch engagement lever 105, which is pivotally mounted at 41. An extension 107 is also formed on the latch engagement lever 105 that projects into the movement path of the movable contact lever 40. Rotation of the armature 104 also produces, via the lug 106 and the extension 107, a rotation of the movable contact lever 40 in the same direction. A latch engagement position 108 is also provided diametrically opposite the lug 106, against which the contact lever 40 is pressed by means of the articulated drive formed from the switch lever 45, rod 46 and bearing 48. In this connection, a leaf spring 109 is guided on the movable contact lever against which spring the shaft 48 presses from above so that the retention and connection between the rod 46 and contact lever 40 constitutes a springactuated connection.

The spring 109 is considerably stronger than the spring 50 since it has to transmit the force of the spring 50, i.e. the contact force, as well as the latch engagement force. The eyelet 110 together with the contact lever 40 forms a type of longitudinal hole 111, and the shaft 48 is pressed by the spring 109 against the upper end, i.e. the end of the longitudinal hole 111 situated opposite the contact lever. In this way an optimum guidance of the articulated drive 45/46/48/40 and a retention of this drive in a stable position readyfortripping, and in the other, tripped position is achieved. The thermostatic bimetal strip 60 acts on the latch engagement lever 105 and rotates the latter in an anti-clockwise direction about the shaft 41 in the event of an overload current. The latch engagement position 108 is thereby freed and the movable contact lever 40 can be moved to the 'switch off' position under the tractive force of the spring 50.

In a tripping event the latch engagement position is thus first of all released and after overcoming the forward movement due to the spacing between the extension 107 and contact lever, the extension 107 acts on the contact lever. The tilting armature remains permanently underthe action of a tension spring 150 which constantly urges the tilting armature in the switch off position and thereby determines the magnetic response value. A spiral spring 152 is also provided which permanently urges the latch engagement lever in a clockwise direction, i.e. presses the lug 108 permanently against the contact lever 40 and thereby ensures the latch engagement.

Claims

1. Electrical switch with a contact position having a fixed and a movable contact member and with an electro-magnetic and/or thermal trip device, said contact position being associated with an arc extinguishing device, according to Patent (p 3242 062.5), characterised in that the magnetic armature (104) acts via a rotary lever (105) disengageable in the off mode of the switch, on the movable contact member (24) to open the latter, in such a way that on rotation of the magnetic armature designed as a tilting armature the rotary lever is also rotated and strikes a contact lever (40) bearing the movable contact member (24) roughly in the direction of the opening movement and roughly vertically with respect to the extension of the contact lever (40).

2. Switch according to Claim 1, characterised in that a lug (106) is formed on the rotary lever (105), which lies in the movement region of the tilting armature (104), and that a latch engagement position (108) is formed on the rotary lever which serves for the latching engagement of the contact lever (40) of the contact position.

3. Switch according to Claim 1 or Claim 2, characterised in that the rotary lever (105) strikes the contact lever (40) roughly in the middle thereof.

4. Switch according to one of the preceding claims, characterised in that the rotary lever is formed as a double-arm lever, one of whose arms bears the latch engagement position and the lug (107) for the contact lever, and whose other arm bears a further lug (106) that cooperates with the tilting armature.