EP0053194B1 - Contact device - Google Patents

Abstract

A contact arrangement includes an elongated striker reciprocable in direction of its elongation and a pair of movable contacts moved by the striker and cooperating with adjacent stationary contacts so that during reciprocation of the striker between two end positions one of said movable contacts engages the stationary contact adjacent thereto while the other movable contact is spaced from the adjacent stationary contact, and vice versa. In order to obtain during the reciprocation of the striker up to the moment of switching the contacts a high contact pressure, the striker is provided with a guide extending transverse to its reciprocation direction for a movable guide body. The movable guide body is mounted on one end of a link member the other end of which is articulately engaged with an angle lever in the region of the knee of the latter. A tension spring is connected at one end to the movable guide body and at the other end to one arm of the angle lever, the other arm of which is pivotally mounted on said support. A stationary guide body is coordinated with the movable guide body and the arrangement is made in such a manner that during the switching movement the movable guide body first moves in one direction along one face of the stationary guide body and then in the opposite direction along an opposite face of the stationary guide body.

Description

The invention relates to a contact device with a longitudinally displaceable plunger and movable contact pieces which can be actuated by the latter and which cooperate with fixed contact pieces to form openers and / or closers.

Contact devices of the type mentioned are known in many different constructions and different areas of application. An example is relays or thermal overcurrent releases, for which the invention is preferably used. In principle, however, the invention can be used in all contact devices in which creeping or slow movements for actuating the contact device can occur and in which sudden switching is nevertheless desired and to be effected.

In the previously known contact devices, the contact pressure between the touching movable and stationary contact pieces is dependent on the actuation stroke or on the switching path, ie. H. the contact pressure decreases during the switchover path until the value zero is reached, i.e. there is practically no contact pressure, and only then does the switchover take place with the contact open. This results in significant disadvantages, in particular unsafe contact making and insufficient vibration resistance in many operating conditions.

This previously explained problem has been appropriately assumed in DE-A-2152483. From this, a switch with snap-action switching mechanism is known, in which the aim is to maintain the contact pressure completely until the time of the switchover, and then to immediately regain the full size of the contact pressure after the switchover in another direction. The known switch has a longitudinally displaceable plunger, to which a pivotably mounted angle lever is articulated. A rocker arm that can be moved between two stops is supported on this angle lever. Furthermore, the switch has a contact tongue which is provided at one end with an electrical connection part and at the other end with movable contact pieces. Depending on the position of the contact tongue, the movable contact pieces interact with one or the other of the two fixed contacts. A tension spring is tensioned between the distal ends of the rocker arm on the one hand and the contact tongue on the other. This tension spring has two tasks, namely to switch the spring switch including the contact tongue when switching the plunger and also to generate the contact pressure not only in the two end positions of the contact tongue, but also during the switching process. The size of the contact pressure generated exclusively by the tension spring is determined by the respective tensile force of the spring and the angle between the line of action of the tension spring and the contact tongue. The smaller this angle during the switching process, the smaller the already very small force component, which can act as contact pressure. During the switching process, the tension spring is pulled further apart by pivoting the angle lever and the rocker arm, thereby increasing the tensile force. However, these two influencing variables, namely angle reduction and increase in tractive force, ultimately have very different effects on the contact pressure. A really constant contact pressure until the respective time of switching cannot be achieved here. This also applies to a proposed exemplary embodiment in which the previously explained angle between the line of action of the tension spring and the contact tongue is kept essentially constant by means of design measures, but the tension force of the tension spring is increased during the respective switching process, so that the contact pressure increases, therefore again is not kept constant. Since the snap-action switching mechanism, the movement of the contact tongue and the contact pressure are dependent on the tension spring as described, adequate contact security is not guaranteed. In addition, the known switch is also very sensitive to shocks, especially if these occur during the switching processes.

In contrast, the invention has for its object to provide a contact device in which a reliable contact is guaranteed and which is vibration-proof, especially when operated automatically or mechanically.

The stated object is achieved in that the plunger has a guide extending transversely to its direction of displacement for a movable guide body, that the guide body is attached to an articulation member, that the articulation member articulates in the region of the knee of an elbow that between the guide body and One leg of the angle piece is provided with a tension spring, that the angle piece is pivotably mounted by means of the other leg, and that the stationary guide body is assigned to the movable guide body and the arrangement is such that the movable guide body is moved in one direction along the path during the switchover one side and in the other direction along the other side of the fixed guide body.

In this way it is achieved that when the contact device is actuated, an unwanted early switching cannot take place because the plunger is immovably held or locked up to precisely defined positions. These precisely defined positions are not determined by the position of the tension spring, but by the mutual position of the movable and the fixed guide body. Furthermore, the tension spring in the contact device according to the invention has no influence whatsoever on the size of the contact pressure, because this can be generated in a conventional manner by separate contact pressure springs. The advantages achieved by the invention are thus essentially to be seen in the fact that a high contact pressure is maintained during the actuation stroke or the switchover path until immediately before the switchover. This results in a safe contact. Furthermore, the contact device is vibration-proof in all operating conditions, in particular also in the case of automatic or mechanical actuation. As a result, the contact device according to the invention is also suitable for low electrical voltages of, for example, 24 volts.

Advantageous embodiments of the invention result from the subclaims.

• Figur 1 ein Diagramm, in dem der Verlauf des Kontaktdruckes über dem Umschaltweg bei einer Kontaktvorrichtung nach dem Stand der Technik veranschaulicht ist,
• Figur 2 ein Diagramm gemäß Figur 1 mit Darstellung des Verlaufes des Kontaktdruckes über dem Umschaltweg bei einer erfindungsgemäßen Kontaktvorrichtung,
• Figur 3 eine schematische Darstellung eines Ausführungsbeispieles einer Kontaktvorrichtung in einer Anfangsbetriebsstellung,
• Figur 4 eine Kontaktvorrichtung gemäß Fig. 3 in einer Betriebsstellung vor dem Umschalten,
• Figur 5 eine Kontaktvorrichtung gemäß Figur 3 in einer anderen Betriebsstellung nach dem Umschalten,
• Figur 6 wiederum die Kontaktvorrichtung gemäß Figur 3 in einer mittleren Betriebsstellung vor dem Zurückschalten,
• Figur 7 die Kontaktvorrichtung gemäß Figur 3 in einer Betriebsstellung nach dem Zurückschalten, entsprechend der Anfangsstellung gemäß Figur 3 und
• Figur 8 eine Draufsicht auf eine maßstäblich mehrfach vergrößerte Kontaktvorrichtung also ein Ausführungsbeispiel im Schema.

The invention is explained in more detail below on the basis of exemplary embodiments illustrated in the drawing. Show it

• FIG. 1 shows a diagram illustrating the course of the contact pressure over the switchover path in a contact device according to the prior art,
• FIG. 2 shows a diagram according to FIG. 1, showing the course of the contact pressure over the switchover path in a contact device according to the invention,
• FIG. 3 shows a schematic illustration of an exemplary embodiment of a contact device in an initial operating position,
• FIG. 4 shows a contact device according to FIG. 3 in an operating position before switching,
• FIG. 5 shows a contact device according to FIG. 3 in a different operating position after switching,
• FIG. 6 in turn shows the contact device according to FIG. 3 in a middle operating position before switching back,
• FIG. 7 the contact device according to FIG. 3 in an operating position after switching back, corresponding to the initial position according to FIGS. 3 and
• FIG. 8 shows a plan view of a contact device that has been enlarged several times to scale, that is, an exemplary embodiment in the diagram.

Figure 1 of the drawing relates to the prior art, specifically on the course of the contact pressure during the switching path. The contact pressure is plotted in Newtons on the vertical coordinate 1, while the switchover path is plotted in millimeters on the horizontal coordinate 2. In the case of a contact device in the cold state, for example in the case of a cold relay, it is assumed in this example that the contact pressure between a movable and a fixed contact piece in the switched-on state is 0.5 N, specifically along line 3. In the operating state, the contact pressure is up to dropped to about half. During the switchover path, the contact pressure drops further according to line 7 and reaches a value of zero after a switchover path of, for example, 0.7 mm at switchover point 4. The contact (normally closed) is therefore opened under a very low contact pressure that goes to zero. After opening, a contact pressure 5 of a closer is created. During the decreasing switchover path according to the dashed line 8, this contact pressure also drops again to a value of zero up to the switchback point 6 of the make contact. When switching over, contact pressure 9 of the break contact is created again. These changes in contact pressure are repeated during the to-and-fro switch path 10.

Figure 2 clearly illustrates the course of the contact pressure in a contact device according to the invention. It can be seen that the contact pressure in the contact device remains the same in the cold state according to line 3 over the switchover path 10 to the switchover point 13 of the opener. After switching, a contact pressure 12 of the closer is obtained, which corresponds to the previous contact pressure 11 of the opener. Here, too, the contact pressure 12 remains the same over the decreasing switchover path corresponding to the dashed line up to the switchover point 14, and after the switchover there is again a contact pressure 15 of the break contact, which corresponds to the contact pressure 11 at the switchover point 13.

Figures 3 to 7 illustrate the construction principle of a contact device according to the invention with a longitudinally displaceable plunger 34 which is held in guides 35, 36. This plunger 34 is used to actuate movable contact pieces 39 and 40, which interact with fixed contact pieces 37 and 38. In the operating position according to FIG. 3, which is to be assumed once, the contact pieces 37, 39 represent a closer and the contact pieces 38, 40 represent an opener.

The plunger 34 has a guide 32, 33 running transversely to its direction of displacement on both sides of a movable guide body 28. This guide body 28, for example in the form of a small block, is attached to one end of a link 27, which in turn articulates with the other end in the region of the knee 18 of an elbow. The contra-angle consists essentially of two legs 16 and 17 which are at right angles to one another and which are rigidly connected to one another in the region of the knee 18. A tension spring 31 is provided between the guide body 28 and the outer end of one leg 17 of the angle piece. The articulation point of the tension spring at the outer end of the leg 17 is given the reference numeral 30. The elbow is on by means of the other leg 16 the outer end of which is pivotally mounted. The reference number 19 denotes the pivot axis of the fixed bearing.

The movable guide body 28, as the drawing shows, is assigned a fixed guide body 29 in such a way and, moreover, the design and arrangement of the above-described components is such that the movable guide body 28 during the switchover path in one direction along one side and in the other Direction along the other side of the fixed guide body 29 is guided.

The tension spring 31 is arranged between the guide body 28 and the articulation point 30 of the leg 17 of the elbow so that its central axis with the center lines of the leg 17 and the articulation member 27 in the two end positions of the switching path according to FIGS. 3 and 7 on the one hand and FIG. 5 on the other hand forms roughly equal obtuse-angled triangles.

On the elbow, and expediently on the leg 16, an actuating lever 20 engages by means of an articulated connecting member 21. The joints at the ends of the connecting member 21 are provided with the reference numerals 22 and 23. Furthermore, a return spring 24 acts on the angle piece, and also expediently also on the leg 16, which can be designed as a compression spring or tension spring, depending on the side arrangement. The return spring 24 abuts a support 25 and is attached to the articulation point 26 of the leg 16. The movable contact pieces 39, 40 are attached to springs, preferably to leaf springs 41, 42, which in turn are fastened in holders 43, 44 with suitable power line connections.

The operation of the contact device described above is essentially as follows. The operating position of the contact device according to FIG. 3 is assumed. In this starting position, the pressure of the return spring 24 causes the angle piece with the legs 16, 17 to pivot out, furthermore the actuating lever 20 with the connecting member 21 and the articulation member 27 with the movable guide body 28 into the left end position, which is limited by the stop. The tension spring 31 extends below the knee 18 of the elbow and generates a force component parallel to the direction of displacement of the plunger 34, so that the movable guide body 28 held in the guide 32, 33 presses the plunger 34 downward, so that the contact between the contact pieces 38 , 40 is closed and open between the contact pieces 37, 39. If you now press the operating lever 20 in the direction of the arrow to the right, the angle piece is pivoted clockwise around the pivot axis 19 and the articulation point 30 of the tension spring 31 moves obliquely upward in the direction of arrow 45. The return spring 24 is compressed and the movable guide body 28 slides along the underside of the fixed guide body 29 with a part elongated perpendicular to the image plane via the guide 32, 33, which is otherwise arranged so that it does not move the guide 32, 33 with special needs. During the sliding of the movable guide body 28 past the fixed guide body 29, an undesired early switching cannot take place and the contact pressure exerted by the leaf spring 42 between the contact pieces 38 and 40 remains unchanged. Due to the pivoting movement of the angle piece about the pivot axis 19, the tension spring 31 finally reaches a position that goes beyond the central position according to FIG. H. the tension spring 31 runs above the knee 18 of the elbow. This results in an opposite force component, namely upwards, but this can only have an effect when the movable guide body 28 is displaced to the right so far that it is released from the fixed guide body 29. At this moment there is a sudden changeover, that is to say opening of the contact pieces 38, 40 and closing of the contact pieces 37, 39. The plunger 34 has shifted upwards in accordance with FIG. 5. If the actuating lever 20 is now released, the return spring 24 pushes the contra-clockwise again towards the starting position, the movable guide body 28 now sliding along the top of the fixed guide body 29 until a middle position according to FIG. 6 is exceeded Force component downwards and by the action of the tension spring 31, the movable guide body 28 together with the guide 32, 33 and with the plunger 34 is suddenly brought into the position according to FIG. The original position according to FIG. 3 is thus reached again. It should also be noted here that the switchover path shown in FIG. 2 is proportional to the displacement path of the movable guide body 28 in the guide 32, 33. It is understood that the mutual displacement movement of the plunger 34 is limited by stops not shown.

The exemplary embodiment of a contact device according to the invention shown in the diagram in FIG. 8 is based on the same principle which has been explained with reference to FIGS. 3 to 7. In a housing 46, which can be closed by a cover (not shown) or the like. An angle piece 47 with two legs running at right angles to one another is mounted on a pivot axis. The tension spring 50 engages on the articulation point 49 and on the other hand on the movable guide body 51. The movable guide body 51 is held in a guide 62 running transversely to the direction of displacement of the plunger 59. The fixed guide body is provided with the reference number 52. The articulation member 53 engages in a bearing 54 which, for example, as Notch is shown. The plunger 59 has an arm 60 which is extended downwards and which interacts with the U-shaped bent leaf spring 76 of the movable contact piece 77. Accordingly, the arm 61 of the plunger, which leads upward, actuates the U-shaped bent leaf spring 70 of the movable contact piece 71 that you can see the respective operating position of the contact device from the outside.

In Figure 8, the operating position is shown, which corresponds to Figure 5, i. H. With its central axis, the tension spring 50 forms an obtuse-angled triangle with the center lines 55, 56 of one leg of the angle piece 47 and of the articulation member 53. The angle piece 47 is held in its swivel range between stops 57 and 58, the stop 57 being held on a bolt 95.

The plunger 59 is expediently guided on both sides between guide pieces 65, 66. A return spring 65 acts on the angle piece 47 again. The special feature of this return spring is that it is adjustable with one end in an internal thread of a return spring holder 68. The internal thread is expediently adapted to the profile of the return spring windings with respect to the thread grooves. The spring end 69 is bent in a straight line so that it runs diagonally with respect to the last spring turn. As a result, the return spring can be adjusted by simply turning it and, at the same time, attacking it with a suitable tool. The movable contact pieces 71 and 77 are again opposite fixed contact pieces 72 and 78, which are guided with the aid of power connection rails 73 and 79 to conventional power connections 75 and 80. The U-shaped current-conducting leaf springs 70, 76 are also extended to power connections 74 and 81.

As explained in connection with FIGS. 3 to 7, an actuating lever 86 again acts on the angle piece 47, with the interposition of a connecting member 83, the articulation point on the angle piece with the reference number 82 and the articulation point on the actuation lever 86 with the reference number 85 is provided. The connecting member 83 is advantageously provided with a spring 84, in the present exemplary embodiment with a tension spring, which dampens the transmission of switching forces.

The exemplary embodiment according to FIG. 8 has another special feature, namely that the actuating lever 86 interacts with a compensation bimetal 89, 90. Advantageously, the compensation bimetal is designed to be angled and pivotally held in a holder at the angled point. The bracket consists, for example, of a cylindrical pin and a counterpart, between which a slot is left for inserting the compensation bimetal. The compensation bimetal lies with one leg 89 on one end 88 of the actuating lever 86 and with the other leg 90 on an adjusting device, which can consist, for example, of a bolt 93 with a thread and an adjusting wheel 94. The compensation bimetal with the adjustment device allows a sensitive adjustment of the actuation lever 86 when the contact device is operated automatically or mechanically. It is easy to see that when the bolt 93 is screwed down, the leg 89 of the compensation bimetal swings out with its lower end to the right in the image in FIG. 8, thus causing the actuating lever 86 to pivot about the articulation point 85, so that the lower end of the actuating lever 86 is pivoted closer to the actuating element, not shown, acting in the direction of arrow 87, so that the switchover takes place earlier, while, when the adjustment device is reversed, the switchover takes place later.

In an advantageous embodiment of the invention, the bolt 93 is guided in a nut 96 provided with an internal thread, which in turn is held rotatably in a sliding seat 97 of the housing 46. The housing 46 is also equipped with a fixed stop 98 projecting up to the level of the setting wheel 94. This cooperates with a projection 99 which is fixedly connected to the setting wheel 94. The principle of operation is as follows. To adjust the setting wheel 94 is first rotated so far that the projection 99 abuts the stop 98. Then the adjusting wheel 94 is moved with the bolt 93 by turning the nut 96 downwards or after the leg 90 of the bimetallic compensation strip. In the correct desired position, the mother is z. B. attached by gluing, clamping or welding relative to the housing 46.

Claims (11)

1 A contact-making device provided with a longitudinally displaceable tappet (34 ; 59) and movable contact pieces (39, 40 ; 71, 77) which are actuatable by the latter and which, for the formation of break contacts and/or make contacts, cooperate with fixed contact pieces (37, 38 ; 72, 78), characterised in that the tappet (34 ; 59) has a guide (32, 33 ; 62), which extends transversely to the direction of displacement thereof, for a movable guide element (28 ; 51), and in that the movable guide element (28 ; 51) is fitted to a link member (27; 53), and in that the link member (27 ; 53) engages articulatedly in the zone of the knee of an angle piece (16,17 ; 47), and in that an extension spring (31 ; 50) is provided between the movable guide element (28 ; 51) and one leg (17) of the angle piece, and in that the angle piece (16, 17 ; 47) is mounted so that it can be swivelled by means of the other leg (16), and in that there is associated with the movable guide element (28 ; 51) a fixed guide element (29 ; 52) and the arrangement is made in such a way that the movable guide element (28 ; 51), during the switch-over path, is guided in one direction along one side of the fixed guide element (29 ; 52) and in the other direction along the other side thereof.

2. A contact-making device as claimed in Claim 1, characterised in that the extension spring (31 ; 50) is arranged between the movable guide element (28 ; 51) and the leg (17) of the angle piece (16, 17 ; 47) in such a way that its central axis forms with the central lines (55, 56) of this leg (17) and of the link member (27 ; 53), in the two end positions of the switch-over path (10), obtuse- angled triangles of approximately identical size.

3. A contact-making device as claimed in Claim 1 or 2, characterised in that an actuating lever (20 ; 86) acts on the angle piece (16, 17 ; 47) by means of an articulatedly fastened connection member (21 ; 83).

4. A contact-making device as claimed in one of the preceding Claims, characterised in that there are provided stops (57 ; 58) for limiting the swivel movement of the angle piece (16,17 ; 47).

5. A contact-making device as claimed in Claim 3 or 4, characterised in that the connection member (83) is provided with a spring (84).

6. A contact-making device as claimed in one of the preceding Claims, characterised in that a return spring (24 ; 67) acts on the angle piece (16, 17 ; 47).

7. A contact-making device as claimed in Claim 6, characterised in that the return spring (67), with one end, sits adjustably in an internal thread of a return spring retainer (68).

8. A contact-making device as claimed in one of the preceding Claims, characterised in that the movable contact pieces (39, 40 ; 71, 77) are fitted to leaf springs (41, 42; 70, 76).

9. A contact-making device as claimed in one of Claims 3 to 8, characterised in that the actuating lever (86) co-operates with a compensation bimetal (89, 90).

10. A contact-making device as claimed in Claim 9, characterised in that the compensation bimetal (89, 90) is designed so as to be angular and is pivotally held in a holder and, with one leg (89), abuts the actuating lever (86) and, with the other leg (90), abuts an adjusting device (93, 94).

11. A contact-making device as claimed in Claim 10, characterised in that the adjusting device consists of a setting wheel (94) with a bolt (93) and a nut (96), and in that the housing (46) is provided with a stop (98) and the setting wheel (94) is provided with a projection (99), and in that the nut (96) is held in a sliding seat (97) of the housing (46).

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