GB2193041A

GB2193041A - Relay

Info

Publication number: GB2193041A
Application number: GB08630746A
Authority: GB
Inventors: Holger Strack
Original assignee: Bach and Co GmbH
Current assignee: Bach and Co GmbH
Priority date: 1986-07-22
Filing date: 1986-12-23
Publication date: 1988-01-27
Anticipated expiration: 2006-12-23
Also published as: GB8630746D0; DE3645337C2; GB2193041B

Abstract

A relay comprises a contact spring (9) connected to the armature (7) by way of a connecting member (8) which has a resilient spring pressing member (54), which in the contact closed position bears against the contact spring (9) to exert a pressing force on the contact spring (9). The connecting member (8) also has a lifting member (57), which in the contact closed position is spaced from the contact spring (9) whereby the contact spring (9) bears with its contact (9a) with a high pressing force against the stationary contact (10) but can be quickly lifted therefrom to prevent arcing. <IMAGE>

Description

SPECIFICATION Relay The invention relates to a relay having at least one coil with an iron core, an armature, at least one contact spring with a contact and at least one normally closed contact, the contact spring being connected by a connecting member to the armature, which is able to move between a first and second switch position, in which in the second switch position the contact of the contact spring bears against the normally closed contact.

Relays are known in which the contact spring lies with its free end in an interlocking manner in a slot in the connecting member constructed as an angular member. It is positively connected to the armature. When the coil is energised, the latter is attracted by its iron core, in which case it entrains the connecting member. The latter is thus displaced in the housing so that even the contact spring is entrained in a corresponding manner and its contact is lifted from the normally closed contact or comes to bear there against. In relays of this type, the contact forces between the contact spring and the normally closed contact are relatively low on account of the mere abutment of these parts one against the other.

Furthermore the contact spring cannot be lifted sufficiently quickly from the normally closed contact, so that frequently arcing cannot be avoided and this leads to relatively rapid wear of the contact parts. Also this re iay is therefore not suitable for high current intensities.

It is the object of the invention to construct a relay of this type for high current intensities so that the contact spring rests with its contact on the normally closed contact with a high contact force and on the other hand can be lifted therefrom in the shortest time.

The invention provides a relay of the aforementioned type wherein the connecting member comprises a resilient spring pressing member, which in the second switch position bears against the cqntact spring with resilient pre-tensioning and in addition to the pre-tension of the spring exerts a pressing force on the contact of the contact spring, and the connecting member is provided with a lifting member which in the second switch position is spaced from the contact spring.

The relay maintains it switch positions according to Figs. 1 and 2 when the coil is not energised. When the contact is closed (transfer from the first into the second switch position) the pre-tensioned contact spring follows the lifting member. In addition the pressing member strikes against the contact spring and increases the contact force. At the same time the pressing member acts in a balancing manner as regards the drive system, i.e. it forms a counter force to the permanent magnetic force.

At the time of the opening process the pressing member lifts first of all. The contact remains closed until the lifting member comes into contact with the contact spring due to its kinetic energy and opens the latter abruptly.

At the beginning of the contact opening operation, the armature has covered approximately two thirds of its movement, so that on account of its permanent magnetic force it is already in a position to bring the pre-tensioned contact spring reliably into the position corresponding to the first position. The relay according to the invention is therefore particularly suitable for high current intensities from approximately 50A to approximately 100A, so that it is suitable for example for the remotely controlled connection of consumer units, such as electrical heating appliances, to the main supply.

Further features of the invention will become apparent from the following claims, description and drawings. The invention is described in detail hereafter with reference to one embodiment illustrated in the drawings, in which: Figure 1 shows part of a relay according to the invention with a connecting member constructed as a rocker for a contact spring in a first switch position, in which it is lifted with its contact from a normally closed contact, in vertical section, Figure 2 shows the relay according to Fig. 1 with the contact spring in a second switch position, in which its contact bears against the normally closed contact, Figure 3 shows the connecting member according to Fig. 1 in side view in the direction of arrow Ill of Fig. 1, Figure 4 shows the connecting member according to Fig. 3 in vertical section on line IV-IV of Fig. 3.

The relay according to Figs. 1 and 2 comprises a coil 1 with a coil core or iron core (not shown), which is surrounded by copper windings and is held in a coil body 2. Provided at the two end faces 11, 1 1a of the coil 1 are pole laminations 3, 4, which are in operative connection with further pole laminations 5, 6 of an armature 7. This armature 7 is located in a connecting member 8 constructed as a rocker, which moves a contact spring 9 with a contact 9a to and fro between a first and second switch position. Located opposite the contact 9a is a normally closed contact 10, from which the contact 9a is at a distance in the first switch position (Fig. 1) of the contact spring 9, whereas its contact bears against the normally closed contact in the second switch position (Fig. 2) of the contact spring.Also provided on one end face 11 of the coil 1 is a movable holder 12 for springs 13a, 13b, 13c for the connection of the coil 1 for a control unit. Finally an additional coil 15 is provided on the other end face 1 1a of the coil and which serves for the electro-magnetic unlocking of the contact spring 9 in its switch positions, which is in operative connection with a locking bar 16.

All these parts are located in a housing, of which only the half 17 is illustrated. It comprises locking members 1 7a for connection to the other half of the housing (not shown). The locking members 1 7b on the end wall of the housing serve for receiving the relay in the control unit. A connection 18 with screws 19, 20 serves for connection to a consumer unit (not shown), such as a heating unit, machine or the like. The mains connection takes place on the support 21 of the normally closed contact 10.

The pole laminations 3, 4 of the coil 1 have the same construction and an L-shape. They are arranged so that their shorter sides 22, 23 lie parallel to the longitudinal axis of the coil 24 and are directed towards each other at a distance below the coil. They project between free ends 25 to 28 of the pole laminations 5, 6 of the armature 7, which project beyond a permanent magnet (not shown). It is sandwiched between the pole laminations 5, 6.

The armature 7 with the magnet and the pole laminations 5, 6 is held in the connecting member 8 and indeed in a support member 29 of U-shaped cross section (Figs. 3 and 4).

The pole laminations 5, 6 are arranged in a form-locking manner in the sides 30, 31 of the support member. They comprise slots 39 to 42 extending between the base 36 of the support member and upper edges 37, 38, into which slots the pole laminations 5, 6 project with projections. They are preferably formed between recesses on the edges of the pole laminations.

The pole laminations 5, 6 lie at right angles to the sides 30, 31 of the support member 29 and project by their free ends 25 to 28 beyond the narrow vertical edges 32 to 35 of the sides. The base 36 of the support member 29 is formed by the lower edges 43, 44 of the sides 30, 31 and transverse ribs 45, 46 connecting the latter to a frame part as well as by an annular part 47 connected to the side edges 43, 44 by way of connecting webs 48, 49.

Provided in the sides 30, 31 of the support member 29 at the height of the connecting webs 48, 49 are bearing bushes 50, 51, which align with pins (not shown) in the housibg or in opposing base plates 52 or the halves 17 of the housing. The connecting member or the connecting rocker 8 may tilt about the axes of these bearing points from one switch position into the other switch position according to whether or not the coil 1 is energised.

The connecting member 8 also comprises an entrainment member 53, which is constructed as an arm having a piurality of parts and projecting freely beyond the support member 29. It is preferably made of synthetic material in one piece with the support member.

The entrainment member 53 has a pressing member 54 for the contact spring 9 in its second switch position, in which it bears by its contact 9a against the normally closed contact 10 with pre-tensioning. The pressing member is constructed as a flat tongue, which is an extension of the base 36 of the support member 29 and is arranged symmetrically with respect to the longitudinal central plane E of the connecting member 8. The pressing member or the tongue 54 is surrounded by a frame-like arm portion 55 of the entrainment member 53, which in plan view preferably has the same contour as the support member 29 (Fig. 3). In side view (Fig. 4), the arm portion 55 has an L-shape. The end wall of the arm portion 55 remote from the support member 29 is extended away from the armature 7 and forms the shorter side of the arm portion.The free edge 57 of the wall 56 is bent at right angles inwards in the direction of the support member 29 and extends parallel beside the tongue 53. The bent edge 57 forms a lifting member, by which the connecting member 8 comes to bear against the connecting spring 9 at the time of tilting from its position shown in Fig. 2 into the position illustrated in Fig. 1 and then entrains it upwards into the first switch position at the time of further tilting and thus lifts it from the normally closed contact.

The free ends 58, 59 of the tongue 54 and of the edge 57 have their cross sections increased in the form of a partial circie on their lower or upper side 60, 61 (Fig. 4). The end faces 62, 63 of the tongue and of the edge lie approximately in a common vertical plane.

Due to the thickened construction of the ends 58, 59, a high linear pressing force on the contact spring 9 and high strength of the tongue 54 and of the arm portion 55 or of its edge 57 is achieved. Also linear abutment has the advantage that the tongue 54 or the arm portion 55 can be lifted easily and quickly from the contact spring 9.

For indicating the position of the connecting member 8 or of the connecting rocker, a lever 64 bent in an approximate L-shape is provided on the end wall 56, which lever adjoins the end wall by its shorter side 65, whereas its longer side 66 projects outwardly through a slot-like opening 67 in a wall 68 in the half of the housing 17. The opening 67 extends in the longitudinal direction of the wall 68, so that the lever 64 can be entrained into its two positions corresponding to the first and second switch positions of the switch spring 9.

The position of the lever 64 clearly shows the switch position in which the spring 9 is presently located.

The lever 64 is arranged approximately over half the width of the lower longitudinal half of the arm portion 55 or of the end wall 56 illustrated in Fig. 3. Also provided on the end wall apart from the lever 64 is an insertion pin 69, which is located laterally beside the lever between the latter and the longitudinal central plane E. It projects only slightly beyond the end wall and projects into an associated insertion opening 70 in the bar 16, which is arranged parallel to and closely adjacent to the housing wall 68. Due to this positive connection between the switch spring 9 and the bar 16, it is ensured that the switch spring cannot be actuated in an unauthorised manner by the lever 64.The bar 16 is locked by means of an iron core 71 of the additional coil 15 and only released when for example when using the relay for heating units, which are to be operated by off-peak current, the additional coil 15 is energised by means of a control current. The additional coil 15 is thus simultaneously energised by the signal for the coil 1 (single or double winding). It thus has no separate connections.

The iron core 71 of the additional coil 15 is arranged to move in the axial direction of the coil and comprises a projection 72, which projects beyond the associated end face of the coil 73 into an opening 74 or 75 in the bar 16. The iron core has a recess 76, in which a spring 77 is located, which is supported on one side against the coil body of the coil and biases the iron core into its locked position illustrated in Fig. 1. When the additional coil 15 is energised, the iron core is pulled back into the coil against the force of the spring 77, in which case its projection 72 leaves the associated opening 74, 75 in the bar 16 and releases it. Then the contact spring 9 may tilt, which is attached to the connection 18 by a screw 79 or is welded to it.Due to the low mechanical and electro-magnetic inertia of the movable iron core 71, it is ensured that after applying the switching signal to the coil, first of all unlocking of the bar 16 takes place, before the latter is brought by the insertion pin 69 of the entrainment member 53 into the desired position and locked again there, due to the fact when the coil is not energised, the movable core 71 engages in the corresponding opening 74, 75.

Thus, effective protection both against manual adjustment by way of the position indicator 64 is automatically provided as well as against alteration of the switch position due to external mechanical influences, such as for example impact.

In the control unit the relay is arrested by a locking arm 17b. In order to compensate for tolerances between this locking arrangement and the connecting members for the coil on the printed circuit board, a holder 12 was ar ranged to move on the flange of the coil body.

It is particularly advantageous that the coil can be wound automatically, due to the fact that the coil flange is connected in a formlocking manner to the holder with the springs 13a, 13b, 13c and its rear soldered connec- tions for the coil wires.

A locating pin 14 of the holder 12 facilitates the insertion of the relay in the control unit.

By way of the holder 12, the relay is displaced on contact parts, pins (not shown) of a control unit or the like. In order to be able to compensate for installation and/or manufacturing tolerances at the time of sliding, the holder 12 is mounted to slide in its longitudinal direction and is provided with the flat springs 13a, 13b, 13c. The spring holder 12 is able to slide in a guide 80 on the end face 11 of the coil body at right angles to the longitudinal axis 24 of the coil. Thus tolerances can easily be compensated for in the direction of movement. However, a compensation of tolerances is also possible at right angles thereto due to the width of the flat springs 13a, 13b, 13c, since their width amounts to a multiple of the diameter of the pins on the printed circuit board.

The bistable, polarized H-armature relay provides the necessary high forces with adequate movements. In order to simplify the control circuit, the coil 1 was designed as a symmetrical double winding. This results in symmetrical force relationships at the armature. The force requirement for actuating a closing contact is different for both switch positions according to Figs. 1 and 2 due to the pre-tension of the contact spring in the closing direction.

In order to adapt the force requirement to the drive system, the connecting member 8 was provided with the resilient spring pressing lever 54, which on the one hand increases the contact force, on the other hand produces a restoring force for the opening operation.

The distances between the pressing lever 58 and contact spring 9 in Fig. 1 or between the entrainment member 59 and contact spring 9 in Fig. 2 are determined for the dynamics of switching and for the additional travel resulting from contact pitting.

They have a close relationship with the total stroke of the armature and the distribution of the permanent magnetic force across the ar mature stroke and the course of the spring pre-tensioning and pressing force over the ar mature stroke.

When the coil 1 is energised, the connect ing member 8 is actuated by way of the pole laminations 3, 4 and the pole laminations 5, 6, so that it tilts from the position illustrated in Fig. 1 in which it bears by the pole lamina tions 25, 28 against the shorter sides 22, 23 of the pole laminations 3, 4, into the other end position (Fig. 2). In this position it bears with the pole laminations 26, 27 against the pole laminations 3, 4 of the coil. Due to the permanent magnet located between the pole laminations 5, 6, it is ensured that when the coil is not energised, the connecting member 8 is held in a stable manner in the two end positions. The permanent magnet in the connecting member 8 thus facilitates bistable end positions when the coil 1 is not energised.

When the connecting member 8 is tilted from the position according to Fig. 1 into the position according to Fig. 2, the tongueshaped pressing member 54 strikes with its end 58 against the free end 81 of the contact spring 9, projecting beyond the contact 9a.

The contact spring is pre-tensioned in the direction of the switch position according to Fig. 2, so that at the time of tilting of the connecting member 8 it immediately comes into this switch position and bears by its contact 9a under pre-tension against the normally closed contact 10. The tongue 54 is constructed as a resilient spring part and in this switch position bears under resillient pre-tension against the contact spring 9 and exerts an additional pressing force on the contact spring, so that its contact 9a bears with a high contact force against the normally closed contact 10.

For opening the switch contact 9a, 10, in the manner afore-described the additional coil 15 and the coil 1 are supplied briefly with current in the opposite direction or in the case of the double winding of the coil 1, the corrresponding part of the winding is supplied with current. The rocker-like connecting member 8 is then swung back from the position according to Fig. 2 into the position according to Fig. 1. In this switch position according to Fig. 2, the lifting member 57 is at a distance from the contact spring 9. When the relay is reversed, this distance is available as an acceleration distance for the lifting member 57 of the connecting member 2. Thus at the time of swinging back of the connecting member 8, the lifting member 57 strikes at high speed against the contact spring 9 and lifts it contact 9a abruptly from the normally closed contact 10.

The acceleration distance is so great that the contact 9a is still torn away immediately from the normally closed contact 10 even if small areas of the contacts 9a, 10 have become welded together. The spacing of the lifting member 57 from the contact spring 9 in the switch position according to Fig. 1 is chosen so that a pitting reserve for the contacts is also taken into consideration. The acceleration distance is thus also available if the contacts 9a, 10 already have some wear.

The resilient spring construction of the pressing member 54 has the advantage that wear of the contacts 9a, 10 is automatically taken into consideration by the spring force.

As a result of the pre-tension, the pressing member 54 always bears firmly against the contact spring 9 and even in the case of wear presses its contact 9a firmly against the normally closed contact 10.

Finally, as a result of the resilient spring construction the pressing member 54 is prevented from springing back several times (bouncing) on coming into contact with the contact spring 9.

Claims

1. A relay having at least one coil with an iron core, an armature, at least one contact spring with a contact and at least one normally closed contact, the contact spring being connected by a connecting member to the armature, which is able to move between a first and second switch position, in which, in the second switch position, the contact of the contact spring bears against the normally closed contact, wherein the connecting member comprises a resilient spring pressing member, which in the second switch position bears against the contact spring with resilient pre-tensioning and in addition to the pre-tension of the spring exerts a pressing force on the contact of. the contact spring, and the connecting member is provided with a lifting member which in the second switch position is spaced from the contact spring.

2. A relay according to claim 1, wherein the pressing member is a tongue of an entrainment member of the connecting member projecting freely beyond a support member.

3. A relay according to claim 2 wherein the support member has a substantially Ushaped cross section and receives the armature which comprises a magnet, which is iocated between two pole laminations.

4. A relay according to claim 2 or claim 3, wherein the entrainment member has an Lshaped cross section and adjoins the latter substantially at the height of the frame-like base part of the support member.

5. A relay according to any one of claims 2 to 4, wherein the entrainment member comprises the pressing member and the lifting member.

6. A relay according to any one of claims 2 to 5, wherein the pressing member is surrounded by a frame-like arm portion of the entrainment member, which comprises the lifting member.

7. A relay according to one of claims 2 to 6, wherein the lifting member is formed by an end wall of the entrainment member on the front side and remote from the supporting member, which is directed away from the coil and is enlarged with respect to the other sides of the frame and forms the shorter side of the L-shaped entrainment member.

8. A relay according to claim 7, wherein the lifting member is formed by the free-edge of the end wall bent in the direction of the supporting member.

9. A relay according to any one of claims 1 to 8, wherein the lifting member extends substantially parallel with the pressing member.

10. A relay according to any one of claims 1 to 9, wherein the coil is not energised, the tractive force of the connecting member in the opening direction of the contacts at the point of opening of the contacts, is greater than the pre-tensioning force of the contact spring.

11. A relay according to any one of claims 1 to 10, wherein at the time of transfer from the first switch position into the second switch position, firstly the contact released by the lifting member closes, and its contact force adjusted by the pre-tension of the contact spring is increased by the resilient spring pressing member, this additional force depending on the geometry and the distance of the pressing member from the contact spring.

12. A relay according to any one of claims 1 to 11, wherein the free end of the pressing and/or lifting member is constructed with an increased thickness so that in the respective switch position of the contact spring and of the connecting member it lies with linear contact on the contact spring.

13. A relay according to any one of claims 1 to 12, wherein seen in plan view towards the connecting member, the end faces-of the pressing and lifting member are substantially in alignment.

14. A relay according to any one of claims 1 to 13, wherein on its end faces respectively the coil comprises an L-shaped pole lamination, whereof the bent shorter sides are directed towards each other.

15. A relay according to claim 14, wherein the pole laminations project with their bent sides between pole laminations of the armature.

16. A relay according to claim 14 or claim 15, wherein in the two switch positions of the contact spring, the pole laminations of the coil bear respectively against another pole laminations of the armature.

17. A relay according to any one of claims 1 to 16, wherein for self-centering of coil connections, a holder with springs is arranged to move on the coil.

18. A relay according to claim 17, wherein the springs are flat and extend in the axial direction of the coil.

19. A relay according to claim 17 or claim 18, wherein the holder is arranged to slide in a guide transversely of the axis of the coil.

20. A relay according to claim 19 wherein the holder is arranged to slide in a guide substantially at right angles to the axis of the coil.

21. A relay according to any one of claims 17 to 20, wherein the holder is provided with a locating pin lying in the direction of the axis of the coil, which pin positions the springs of the holder with counter plugs of a printed circuit board of a control unit.

22. A relay according to any one of claims 1 to 21, wherein the contact spring can be locked in at least one switch position.

23 A relay according to claim 22 wherein the contact spring can be locked in two switch positions.

24. A relay according to claim 22 or claim 23, wherein an additional coil is provided for unlocking the contact spring.

25. A relay according to claim 24, wherein the additional coil is located adjacent the coil in the axial direction thereof.

26. A relay according to claim 25 wherein the additional coil is constructed as part of the winding of the coil.

27. A relay according to claim 25 wherein the additional coil is constructed as a separate coil.

28. A relay according to any one of claims 24 to 27, wherein an iron core of the additional coil is arranged to move axially in the additional coil.

29. A relay according to claim 28, wherein the iron core of the additional coil is held in an indexed position under the force of a spring, in which position it projects by an indexing projection in to an indexing opening of a locking part.

30. A relay according to claim 29, wherein the locking part is connected to the connecting member.

31. A relay according to claim 29 or claim 30, wherein in the region of a free end thereof the locking part comprises an insertion opening into which an insertion member of the entrainment member projects.

32. A relay according to claim 31, wherein the insertion member projects beyond an end wall of the connecting member remote from the supporting member, and lies substantially parallel with, and at the height of, a base of the supporting member.

33. A relay according to any one of claims 29 to 32, wherein the locking part extends adjacent, and parallel with, a side wall of a housing and is constructed in the form of a bar.

34. A relay according to any one of claims 1 to 33, wherein the contact spring has the property of a spring due to having a short section thereof of reduced cross section.

35. A relay according to one of claims 1 to 34, wherein a support for the normally closed contact can be inserted in an edge of a lower half of a housing so that it is held there positively, and at the time of connection of the mains supply lead, the torque does not bring about any force tending to drive two halves of the housing apart.

36. A relay substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.