DE2411772A1 - ELECTRIC SWITCH WITH REVERSIBLE CONTACT PIECES THAT ARE NORMALLY CLOSED OR NORMALLY OPEN - Google Patents

Description

Electrical switch with changeable contacts that are normally closed or normally open

The invention relates to electrical switches which are adjustable in advance so that the contacts normally are open or normally closed. In particular, the invention relates to switches for small electrical outputs, which are operated by machines or operators and where there is the possibility of contact pieces that are closed at rest are to be converted into contact pieces that are open at rest, or vice versa, which is to be done by assembly steps that change the distance between the contact pieces.

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As is known, a switch of the type described above consists of fixed and movable parts. The fixed ones. Parts are generally made up of a cover, a housing and the terminals with the fixed supply contacts together, while the movable parts consist of an actuator to which a movable contact carrier bridge heard.

The actuation device is mechanical push or push forces exposed that are exercised on them. The displacement of the actuator is made by an elastic system controlled, which generally consists of two springs.

There are known ways to change the (normal) idle state of a switch by simply changing the distance between the fixed and moving contact pieces is changed. For example, in British Patent 784,777, a System described in which the normally closed contacts by a system with normally open contacts can be replaced by rotating the actuator through an angle of 180 °.

However, this system has the disadvantage that the location of the two springs that control the displacement of the actuator must also be changed. In this operation there is a risk that one or both springs will be lost and the switch can no longer be used.

It would be possible to design a switch in such a way that the system of normally closed contacts through the system with normally open contact pieces could be exchanged.e or vice versa, by removing the fixed contact pieces from certain cavities formed in the housing to certain other cavities in the same housing will.

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In this pallet, if the shape of the terminals is retained, the ends of which carry the fixed contact pieces, the system have the disadvantage that a different cover should be provided for the two possible rest states of the switch for the exit of the terminals, which according to the one or another idle state are arranged differently.

The purpose of the present invention is to provide a switch which does not have the aforementioned disadvantages.

The aim or the object of the present invention is seen essentially in providing an electrical switch create that of a company with normally open contacts can be converted into operation with normally closed contacts and vice versa.

According to the invention, a switch of the aforementioned type contains a Housing having a first and a second pair of cavities spaced from and opposite one another are,

two Z-shaped supply terminals, of which the lower one or the first branch or branch carries a fixed contact piece on the inside of the cover and the upper or second Branch or branch forms the connection with an electrical circuit outside the housing, the lower branches of the supply terminals Are arranged in the first or second cavity pairs in such a way that the switch in one case normally has closed contact pieces and in the other case normally open contact pieces,

a cover that fits over the housing and a pair of slots has through which the upper branches of the supply terminals protrude

the housing further includes a movable bridge leading to the two each other opposite contact pieces in the respective positions fits, and 409838/0352

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has an actuating device for moving the bridge from an idle state to an operating state and vice versa, which corresponds to the changes in operation of the electrical circuit with which the upper branches of the supply terminals connected, and

the terminals are shaped so that the plane containing the forms one branch of each terminal, with respect to the plane corresponding to the other branch by an angle between 20 and rotated 40 ° so that the lower or first branches are located in either the upper or lower cavities, the upper or second branches always coincide with the two slots formed in the cover of the housing, and the slots occupy an intermediate position with respect to the position of the cavity pairs.

The switch according to the invention makes it possible of the To switch the system with normally open contacts to the system with normally closed contacts and vice versa, the same parts from which are always used in the two states of rest that are possible as desired the switch is set up. It has also been found that the particular angle of inclination required for the branches of the terminals is provided, has the advantage that it has a number of superposed switches for a screwdriver Passage between the terminals protruding from the cover supplies and facilitates its handling for normal connection work with electrical circuits.

The invention will now be based on further features and advantages the following description and the drawing of an exemplary embodiment explained in more detail.

Figure 1 is a cross-sectional view through the housing parallel to the cover and through the interior of the switch normally open contacts.

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Figure 2 shows a cross-sectional view similar to Figure 1 of the interior of the switch with normally closed Contact pieces.

Figure 3 shows a terminal of the switch. Figure * J shows the cover of the switch. Figure 5 is a front view of the switch.

As already stated, the electrical switch shown in the drawing can be converted from normally closed contact pieces to a system in which the contact pieces are normally open, and vice versa. The conversion is brought about solely by the fact that the arrangement of the terminals in one or the other pair of cavities formed in the housing is changed without changing the cover itself or paying special attention to the process of its arrangement on the housing when the conversion has been executed. In particular, the switch 1 shown in Figures 1 and 2 has a housing 2, which is preferably made of a thermosetting synthetic material, and two Z-shaped terminals, which are shown in Figure 3 in detail and their stationary contact pieces 3 and 4 in one Height with the ends of the lower branches are arranged. The housing has two pairs of cavities. In the pair formed from the cavities 5 and 6, as shown in Figure 1, the fixed contact pieces 3 and 4 are received. This ensures that the switch functions with normally open contacts. Furthermore, a second pair of cavities 7 and 8 is provided at a distance from the cavities 5 and 6 and opposite them and designed accordingly in order to receive the stationary contact pieces 3 and k (see FIG. 2). This ensures the function of the same switch with normally closed contact pieces.

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The interior of the housing furthermore contains the movable parts of the switch, namely a bridge 9, one end of which carries the contact pieces 10 and 11 opposite one another, while the other end carries the contact pieces 12 and 13 also opposite one another, and an actuating device 14 which can be actuated from the outside via a plunger protruding from the housing or a push rod 15 and which has a bearing or a seat 16 (the interior of which contains the bridge 9) and an annular guide 17.

The bridge 9 is also movable on the inside of the bearing.

The actuator that exposed the thrust effects which are exerted on the plunger 15, the bridge shifts from a rest state to an operating state and vice versa with the resulting changes in the switching state in the circuit connected to the second or upper branches of the Terminal of the switch is connected.

For the purpose of controlling the displacement of the actuating device, elastic means are provided which consist of a first and a second cylindrical spring, which are denoted by 18 and 19, respectively. Each of these springs has an end turn which can act on one of the surfaces of the bridge.

One end of the first spring 18 is pressed in movable contact against a wall of the housing. At the same height with the opposite end, certain turns are inserted into the circular guide 17, and the end turn presses against the bridge 9 (see Figures 1 and 2).

The second spring 19 is completely inserted into its bearing 16. One end presses against the bridge 9 and the other

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is placed in movable contact against the wall 20 of the actuator. The two feathers are the elastic ones Means usually used to control the displacement of the actuator and to move the bridge with respect to the actuator can be used.

In Figure 3 is a terminal of the switch according to the invention shown. It should be remembered that each terminal serves to support the fixed contacts and for to provide the electrical connection with a suitable circuit. The terminals according to the present invention have a special shape in order to make the Operating mode with normally open contacts to that with normally closed contacts and, to make the reverse possible by simply placing the fixed contact pieces in one or the other pair of cavities in the housing to be ordered. In particular, each terminal is Z-shaped. The lower or first branch a on the inside of the housing serves to support the fixed contact and the upper or second branch b on the outside of the housing serves for connecting an electrical circuit which is not shown in the drawing.

According to the embodiment shown in the drawing. is the plane that forms one branch of the Z, at an angle rotated by 30 ° with respect to the plane forming the other branch -. The top or second branches of the two terminals are preferably formed by planes that run parallel to one another. The formation of the terminals with this special Z-shape, in which the twigs or branches of the connecting terminal forming two levels in a special way are arranged as described above, ensures that both under the operating conditions shown in Figure 1, in which the contact pieces are normally open, as well as under the operating conditions shown in Figure 2, in which the

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Contact pieces are normally closed, the orientation of the two upper branches of the connection terminals is always the same.

In other words, regardless of whether the terminals are arranged with the lower or first branches in the cavities 5 and 6 or in the cavities 7 and 8, the upper or second twigs or branches always in the same position upwards out of the housing. This makes it possible one and the same for the switch under both operating conditions Use a cover that has only two slots to keep the upper twigs from the connections can stick out. These branches are then with respect to the The plane forming the lower or first branches inclined at an angle equal to that of the upper or second branches is. Furthermore, the slots in the cover are in an intermediate position with respect to the location of the two pairs of cavities generated.

Figure ¹ J shows the cover 21 with the two slots 22 and 23, from which, when the cover is in its intended position on the housing, projecting branches, the branches or the terminal. The dimensions of the slots are the minimum required passage of the branches of the terminals to prevent debris from entering the housing.

The cover is made of synthetic material, preferably is thermoplastic. It engages the housing by clamping means provided on these two parts. In detail the clamping means which are provided in the cover, as can be seen from FIG. 4, consist of at least two Teeth or legs 25 and 26 with windows 27 and 28 respectively provided at opposite ends of the cover and perpendicular to the plane containing them and down. are directed.

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The gasket means provided on the housing consist of at least two protruding elements 29 and 30 (see Figure 5), which on opposite surfaces of the housing in one are positioned corresponding to the legs of the cover, so that when these two parts are united, the protruding ones Elements are inserted into the windows 27 and 28 of the legs 25 and (see Figures 1, 2 and 5) · The cover is usually provided with a stop (not in the drawing shown), so that when the cover engages the housing, the stop, the actuating device 14 in the in Figures 1 or 2 positions shown. An advantage that comes from using the above-described gasket means to connect the Cover with the housing is achieved, is that these means, although they do not affect the interior of the housing, allow a simple arrangement of the various parts of the switch and also facilitate the assembly work.

The mechanical connection between the terminals and the wires by soldering or, preferably, (see Figure 5) with the aid of two wire terminals 31 and 32, the respective clamping plates 33 and 3 ¹ J and the clamping screws are inserted into corresponding threaded holes 35 and 36, which are provided at the end of the upper and second branches, respectively, of the two connecting terminals. The wires are inserted by unscrewing the clamping screws 35 and 36 and then sliding the plates 33 and 3 ^ together with the screws, creating a suitable free space on the shaft of the screws. The final connection of the wires with the switch is done by tightening the same screws in the threaded holes of the terminals and by attaching the actual wires between the plates and the branches of the terminals. Finally, the switch includes two separating or intermediate plates 37 and 38 (see Figures 4 and 5) » which are provided on the cover to cover the upper branches of the connection

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clamp compared to those of other terminals .electrically to isolate, if several switches are arranged one above the other, and to ensure the safety distance between the upper branches and to enlarge any neighboring metal parts.

The operation of the various components of the electrical switch according to the invention will now be explained in more detail. FIG. 1 shows the states that occur when the contact pieces are normally open, and Pijgur 2 shows the states that exist when the contact pieces are normally closed. Under the conditions shown in Figure 1 circumstances, the bridge 9 occupies a rest state in which the contact pieces 10 and 12 are clocked by the fixed Kon pieces 3 and ¹ I separately disposed in the first pair from the cavities 5 and 6. FIG. These states are kept unchanged by the spring 18 which acts on the base plate of the circular guide 17 via its own end turn which resiliently counteracts the displacement of both the actuating device 14 and the bridge 9.

When a surgeon or a machine exerts a thrust on the plunger 15 of the actuating device, the bridge 9 undergoes a displacement in two phases or stages.

During the first phase or stage, the bridge is moved with the actuator, keeping its position on the inside of the bearing remains unchanged, since one side of it always remains in contact with the end turn of the spring 18, which is gradually compressed. The other side of the bridge is in contact with the spring 19, which is not yet compressed is. In the second phase or stage, the bridge is in the operating state, the changes in the electrical state of the electrical circuit. This operating state of the bridge begins when the contact pieces 10 and 12 against

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the fixed contacts 3 and 4 are pressed, and he continues during the period in which there is axial pressure on the actuator, i. H. above that Period in which the contact pieces 3 and 4 are pressed against the contact pieces 10 and 12.

In this phase or stage, the spring 19 is gradually compressed, one end of which is located on the wall 20 of the operating device in motion, while the other end is arranged on the bridge 9, which now belong to the contact pieces 10 and 12 against the fixed contacts 3 and 4 pushes and is thus in a fixed position with respect to the cover.

The gradual compression of the spring 19 increases the pressure between the fixed contact pieces 3 and 4 and the contact pieces 10 and 12, thereby ensuring effective electrical connection with the circuit associated with the upper and second branches of the terminals is connected.

As soon as the pressure exerted on the plunger 15 ceases, it moves the bridge moves away from the position it was in, as described above. The bridge then returns due the action of the spring 18 returns to the position shown in FIG.

If the operating states of the switch shown in FIG. 2 are required, those of the system with normally closed Contact pieces correspond is to change the position of the connection terminals nothing more is required than the connection terminals from the two cavities 5 and 6 into the two cavities 7 and 8 su move. This is done as follows: The feeder wires are taken from the top or second branches the terminals are removed by loosening and removing the clamping screws 35 and 36 (see FIG. 5);

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then the cover is pulled out of the housing, these two parts so far by the clamping means already described were locked together;

furthermore, the two terminals are released from the cavities 5 and 6 taken out and rotated through an angle of 180 °, whereupon they are inserted into the cavities 7 and 8, see above that the fixed contact pieces 3 and 4 on the contact pieces 11 and 13 of the bridge are directed; then the housing is closed again by the cover, by inserting the upper branches of the terminals between the two slots provided on the cover, whereupon the housing and the cover are locked together with the clamping means described above; Finally, the lead wires / are connected to the upper branches of the connection terminals by tightening the terminal screws 35 and 36 are inserted into the threaded holes in the upper Branches of the terminals are provided.

After these operations have been carried out, the switch is in the state shown in FIG. This condition corresponds to the system with normally closed contact pieces.

The new operating state of the switch differs from that shown in Figure 1 in that when the bridge is in Rest state, their contact pieces 11 and 13 are associated with the fixed contact pieces 3 and 4, which are arranged in the cavities 7 and 8.

Furthermore, in contrast to Figure 1, the presence of the fixed contact pieces, the contact pieces of the bridge are assigned, ensure that the end turn of the spring l8 no longer with the base (base) of the circular guide the actuator is in contact.

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Upon a detailed study of the way in which the switch works when the contacts are normally closed shows / that * in this case also two different Phases or stages occur after mechanical influences have been exerted on the approach 15:

A first phase or stage, in which the pressure is exerted on the extension 15, causes a compression of the spring 19, while the stronger spring 18 experiences no compression, so that the bridge 9 remains in its original position in which the contact pieces 11 and 13 against the stationary contact pieces 3 and ² I. These operating conditions ensure that the switch is unaffected by minor random vibrations in the actuator.

Furthermore, a second phase or stage occurs, at the beginning of which the end turn of the spring 18 is against the base of the circular guide 17 declines due to the progressive movement of the actuator.

In this case, the bridge 9, which is no longer prevented from moving by the action of the spring 18, from the Idle state moves out and assumes an operating state in which the fixed contact pieces 3 and 4 of the contact pieces 11 and 13 are separated, causing changes in state in the electrical connected to the upper branches of the connecting terminals Circuit.

As soon as the axial pressure exerted on the ram is released, the bridge reverses due to the action of the no longer compressed Springs back to rest

As can be seen from the above description, works the switch both in the operating mode in which the contact * - pieces are normally closed, as well as in the operational

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art. with normally open contact pieces in an inherently usual manner. As has already been stated, the convertibility from one operating state to another is ensured by the simple displacement or displacement of the connection terminals so that their upper or second branches or branches are inclined with respect to the plane formed by the lower or first branches. The range of this inclination angle of 20 to 40 ° is particularly desirable because of the fact that it offers the further advantage that with switches arranged one above the other, there is a passage for the screwdriver between the terminals protruding from the cover and its action on the wire clamping screws of the underneath located Sehalters is facilitated.

If this latter advantage is not required, according to a further exemplary embodiment of the invention, the angle of inclination of the branches or Xths of the connection terminal can go beyond the aforementioned range.

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Claims (5)

Expectations Electric switch that is operated from an operating state in which the contact pieces are normally open, can be converted into an operating state in which the contact pieces are normally are closed, and vice versa, characterized by a housing (2) which has a first and a second pair of cavities (5, 6; 7, 8) which are spaced from and opposite one another are, two Z-shaped connection terminals, of which the first or lower branch (a) has a fixed contact (3 or 4) on the inside of the housing and the upper or second branch (b) has a connection to an electrical circuit arrangement on the outside of the housing, the first or lower branches (a) of the terminals in the first or second pairs of cavities (5-8) can be arranged, so that in one arrangement the puncture of the switch (1) with normally closed contacts and in the other arrangement the puncture can be carried out with normally open contact pieces, a cover which fits over the housing (2) and has a pair of slots (22, 23) through which the second or upper branches (6) of the connecting terminals can be led out, the housing (2) inside a movable bridge (9) which is provided with two opposing contact pieces (10, 11; 12, 13) on its two ends, and an actuating device device (14) has for shifting the bridge (9) from an idle state to an operating state and vice versa, which correspond to the state changes of the electrical circuit arrangement connected to the upper branches of the connecting terminals, being the level covering one branch of each terminal forms, in relation to the level that the 409838/0352 another branch or branch corresponds to an angle between 20 and 40 ° is rotated such that the first or lower Branches (a) are arranged in either the upper (5, 6) or lower (7, 8) cavities, while the second or upper Branches (6) always coincide with the two slots (22, 23) provided in the housing cover, which with respect to the positions of the cavity pairs assume an intermediate position. 2. Electrical switch according to claim 1, characterized in that the second or upper Branches of the two terminals by parallel to each other Levels are formed. 3. Electrical switch according to claim 1 or 2, characterized in that the cover on the Engages the housing via clamping means provided in these two parts. 4. Electrical switch according to claim 3, characterized characterized in that the clamping means provided in the cover have two legs (25, 26) with pen stars (27, 28) which are arranged level with at least two opposite ends of the cover and are perpendicular are arranged to the plane of the cover and directed downwards, while the clamping means provided in the housing off at least two protruding elements (29, 30) disposed on the opposite surfaces of the housing are, correspond to the legs (25, 26) of the cover and in the assembled state of cover and housing in the windows (27, 28) of the legs are inserted. 5. Electrical switch according to one or more of the claims 1 to H _3, characterized in that the cover has separating or intermediate plates (37, 38) for the electrical insulation of the second or upper branches of the connection terminals. 409838/0352