EP0500138B1 - Protective switch - Google Patents

Abstract

A protection switch with sudden switching on and off, a trip-free release and forced opening is described. A manually movable actuator (10) forms with a U-clip (50) a toggle lever. One leg (51) of the U-clip (50) forming the toggle joint axis is displaceably guided in the actuator (10) in a link (15) with a variable spacing from its rotation axis (11) and against the action of a spring (14) supported on the actuator (10). The other leg (52) of the U-clip (50) is guided in a fixed link (25) and in a ratchet lever (40). The ratchet lever (40) serves to transfer movement to a contact arrangement (21, 22) and cooperates with the release ratchet (60) of an overcurrent and/or undervoltage monitoring device. The fixed link (25) controls the engaging movement of the ratchet lever (40). In an intermediate position of the ratchet lever, it has a detent (26), which only releases said other leg (52) of the U-clip (50) following the further movement of the actuator (10) over and beyond the dead center position of the toggle lever (10, 50) and the tensioning of the spring (14) for sudden contact closure. The construction requires a minimum of parts, particularly if the spring (14) is directly shaped onto the actuator.

Description

Technical field

The invention relates to a circuit breaker, in particular device circuit breaker, with a single-pole or multi-pole contact arrangement, with a rotatably mounted actuating member which can be moved manually between a switch-on and a switch-off position, with a further toggle lever leg forming a toggle lever with the actuating member as the first toggle lever leg, and with a two-armed ratchet lever for transmitting motion between the actuating member and the contact arrangement, the ratchet lever cooperating with the contact arrangement by means of a contact arm and with the release pawl of an overcurrent and / or undervoltage monitoring device by means of a trigger arm and being pivotally supported in between at the end of the further toggle lever leg, wherein the first toggle lever leg formed by the actuating member counteracts its action with respect to its length determined by the distance between the toggle lever joint axis and the axis of rotation of the actuating member he spring can be shortened by the toggle joint axis being fixed to the further toggle lever leg and being displaceably guided against the action of a spring in a first link extending in the actuating member at a variable distance from the said axis of rotation, the mentioned end of the further toggle lever Leg carries an axle pin, which in a fixed, the switch-on movement of the ratchet lever controlling further backdrop is guided, with a latching of the axle pin in the further backdrop during the switch-on movement is provided at least until the dead center position of the toggle lever is provided at an intermediate position of the ratchet lever, and a spring is provided which latches during the switch-on movement during the spindle is tensioned and which causes a sudden contact closure after releasing the locking with at least partial relaxation.

In addition to manual switching on and off, circuit breakers must perform various functions with high reliability: In the event of overcurrent and / or undervoltage in the circuit of the device to be protected - which is determined by appropriate monitoring devices - they must trip automatically, i.e. interrupt the circuit; automatic contact opening must also be ensured if the actuating element is blocked in the switch-on position (so-called free tripping). In addition, it should be possible to separate the contacts by acting on the actuator, even if they are welded together or otherwise stick together (so-called positive opening).

In order to ensure a long service life or the reliable mode of operation and compliance with the trigger values once set, even after a large number of switching operations, the switch design must ensure that the wear and tear is as low as possible, in particular low contact wear. There is therefore an additional requirement on the switching and triggering mechanism that the opening and closing of the contacts is erratic, and cannot be influenced by the manual movement of the actuating member ("switch-off and switch-on jump"). In all of this, the circuit breaker should take up as little space as possible and, last but not least, be inexpensive to manufacture in large quantities.

State of the art

A switch according to the preamble of claim 1 with the design features mentioned above is known from FR-A1-2 628 261. The known switch is constructed using a large number of parts which are expensive to manufacture and in particular to assemble. Above all, it has a plurality of springs. Both toggle lever legs are adjustable in length. The axle journal is locked in the fixed link by means of a further link in a part which is movable and is provided for this purpose in relation to the first link.

From DE-A-28 09 754 a device circuit breaker is known, which also has some of the design features mentioned above, but in which a "creeping" opening and closing of the contacts is possible when operated by hand; the sudden opening is only certain when the latch lever is automatically triggered by the monitoring device.

EP-A1-0 205 361 describes a jump switch for a miniature switch in which an intermediate member loaded by a spring is inserted between a toggle lever and the actuating member. The spring switch-on is effected by this spring, which is tensioned when switched on. An axle journal at the "free" end of a toggle lever leg designed as a U-bracket is guided in a link which is provided with a catch for the axle journal in an intermediate position. The length of both toggle lever legs is constant. The locking of the axle pin in the link is forcibly carried out by moving the link. This is cut in a specially designed movable part.

From DE-U1-87 01 048.8, a switch lock for a circuit breaker with only one pseudo-fast engagement is known, which by guiding the toggle joint axis in a fixed backdrop provided with a slope, running on a circular ring around the axis of rotation of the actuating member. In the known construction, disadvantageous transverse forces occur on the moving parts.

Presentation of the invention

The aim of the invention is to provide a circuit breaker which meets the requirements mentioned at the outset, but which manages with fewer parts. This is achieved according to the invention in that the further toggle lever arm is constant with respect to its length, which is determined by the distance between the toggle arm joint axis and the axle journal, in that only one single arm is attached to the actuating member to act on the toggle lever joint axis and to effect the abrupt contact closure supporting spring is provided, and that the journal is held in the further setting during the switch-on movement only by abutment against a catch formed in the setting, from which it automatically slides after overcoming the dead center position of the toggle lever.

Particular embodiments of the circuit breaker defined in claim 1 are given in claims 2 to 11. Claims 10 and 11 relate in particular to possible configurations of the switch for actuating an auxiliary contact unit arranged outside; this additional possibility is given in a particularly advantageous manner in the circuit breaker according to the invention.

The invention is explained in more detail below using an exemplary embodiment in conjunction with the drawing.

Brief description of the drawings

Fig. 1

2 is a schematic partial illustration of a device circuit breaker according to the invention in the switched-off position,

Fig. 2

is the corresponding representation of the switch in the switched on position,

3 to 6

show a highly schematic representation of a switch-on process in four successive movement phases,

Fig. 7

is a schematic diagram of the parts in the area of the release pawl (viewed in the longitudinal direction of the pawl lever towards the release pawl) to explain the switch-off process,

Fig. 8

schematically shows an auxiliary contact unit actuated by the switch when the switch is switched off, and

Fig. 9

is the corresponding representation when the switch is switched on.

Ways of Carrying Out the Invention

The device circuit breaker according to FIGS. 1 and 2 is generally constructed as follows: the contact arrangement, consisting of the fixed contact 21 and the movable counter contact 22; is mounted on a fixed support 20 (both shown broken off) arranged in a switch housing 2; the latter is located at the free end of a contact spring 23 which is attached to the connection 24. It is preferably a two-pole switch, a similar contact arrangement being mounted on the rear of the carrier 20 (as seen in FIGS. 1 and 2). The one described below The actuation and release mechanism is then assigned to both contact arrangements together. A rocker 10 is provided as the actuator for manual switch actuation. This is pivotally mounted on an arm 31 (FIG. 2) of the carrier 20 by means of an axis 11 and can thus be pivoted optionally into the switch-off position according to FIG. 1 or the switch-on position according to FIG. 2. In a manner known per se, the rocker 10 can be designed in two parts with an internal rocker support and an external, interchangeable "cap". A rocker spring 12 wound around the rocker axis 11 is supported with one end on a cam 13 of the rocker and with the other end on a cam 28 of the carrier and is tensioned when the rocker is pivoted into the switched-on position.

The rocker 10 forms, so to speak as the first toggle lever leg, with a further toggle lever leg 50, which is described in greater detail below, a toggle lever, the articulation axis of which is designated 51. At the "free" end 52 of the toggle lever leg 50, a two-armed ratchet lever 40 is supported, which is used for transmitting motion between the actuating member 10 and the contact arrangement.

One arm 41 of the ratchet lever 40 - referred to here as a "contact arm" - works together with the contact arrangement or with the contact spring 23. The other arm 42 - here called the "release arm" - on the other hand interacts with the release pawl 62 of a monitoring device, not shown. In a manner known per se, the release pawl 62 can be arranged on one arm of a release lever 60 designed as an angle lever. This is mounted on the carrier 20 by means of an axle 61 and is normally held in the position shown by a compression spring 65, which is supported between a fixed cam 29 and the other arm of the release lever. The monitoring device, not shown, moves in the direction of arrow A (FIG. 2) onto the release lever 60 in order to pivot it counterclockwise against the force of the spring 65. It can are an overcurrent release (thermal, magnetic) and / or an undervoltage or shunt relay or a mechanical safety release. A pawl edge 46 of the pawl lever 40 is supported on the pawl surface 63 of the release pawl 62 when the switch is switched on (FIG. 2). If the trigger lever 60 is pivoted as described, the pawl edge 46 slides off the surface 63, which triggers the circuit breaker.

The special design of the switching mechanism is now described below, which ensures a jerky contact closure upon switching on, which cannot be influenced by the manual movement of the actuating member 10 (“switch-on jump”). The schematic FIGS. 3 to 6 serve to illustrate the movement sequence. FIG. 3 corresponds to the switch-off position according to FIG. 1, FIG. 4 shows the situation after a first partial movement, FIG. 5 after a further movement shortly before the jump, and FIG. 6 corresponds to the switch-on position according to FIG. 2.

The hinge axis 51 of the toggle lever 10, 50 can be displaced along a link 15 in the actuating member 10. The link 15 extends in the actuator 10 at a variable distance from its axis of rotation 11. By moving the knee joint axis 51 in the link 15, the length of the toggle lever leg formed by the actuator 10 changes, which is determined by the distance between the knee joint axis 51 and the axis of rotation 11 of the actuator 10 is determined. The axis 51 is further displaced against a bending or leaf spring 14 which engages on the knee joint axis 51 and is supported on the actuating member 10 and which bears against the axis 51 with some pretension.

The toggle lever leg 50 is designed as a U-shaped bracket which on the one hand forms the toggle lever joint axis 51 and on the other hand forms an axle pin 52 which is parallel to the joint axis and which represents the end of the toggle lever leg 50, ie the two Parallel legs of the U-bracket form the two axes 51 and 52. The pawl lever 40 is pivotally supported on the axle pin 52, namely in an elongated hole 43 which extends approximately in the longitudinal direction of the pawl lever and in which the pin 52 can slide when the switch is actuated . In addition, the journal 52, which represents the end of the toggle lever leg 50, is guided along a fixed link 25. This backdrop is present on the carrier 20 and controls the switch-on movement of the ratchet lever 40 in the following manner: If the actuating member 10 is pivoted clockwise starting from the switched-off position (FIGS. 1 and 3), the toggle lever 10, 50 is thereby "stretched" . In a first movement phase, the pawl lever 40 is pressed down by the leg 50. His contact arm 41 leads the movable contact 22 up to a short distance from the fixed contact 21, and the pawl edge 46 on the trigger arm 42 comes to rest on the pawl surface 63 of the trigger pawl 62 (FIG. 4). During this first phase, the leg end 52 is also pushed forward in the elongated hole 43 and reaches a bulge 26 in the link 25. The bulge 26 forms a catch for the end 52 in this intermediate position of the ratchet lever 40. When the actuating member is pivoted further the end 52 initially "caught" in the catch 26 and the position of the ratchet lever 40 unchanged. In contrast, the hinge axis 51 moves upwards along the link 15, whereby on the one hand the toggle lever leg formed by the actuating member 10 is shortened and on the other hand the spring 14 is tensioned. This situation emerges from FIG. 5, in which the toggle lever 10, 50 is shown approximately in its dead center position or shortly before reaching this position. The shortening of the toggle lever leg formed by the actuating member 10 is necessary so that the actuating member 10 can continue to move after the end 52 has been latched on the catch 26 and the toggle lever can be moved past its dead center.

In the aforementioned sequence of movements, the toggle lever leg 50 changes its direction with respect to the link 25 (comparison of FIGS. 4 and 5). Therefore, when the actuator continues to move in the situation shown in Fig. 5 or shortly thereafter, i.e. after passing through the deadlock suit, inevitably causes the end 52 of the detent 26 to slip, i.e. that the catch releases the toggle lever leg 50 and the ratchet lever 40. Under the action of the tensioned spring 14, the toggle lever leg 50 then jumps downward along the fixed link 25 and the link 15, the end 52 taking the latch lever 40 with it for jerky contact closure. The pawl lever 40 pivots about its pawl edge 46 resting on the pawl surface 63, but only by a relatively small angle: as a result of the above-mentioned initial approach of the contacts, the contact path which has to be covered in leaps and bounds up to the closing of the contact is only slight, which contributes considerably to avoiding undesired contact bruising . The abruptly setting end position (switch-on position) is shown in FIGS. 2 and 6.

It is particularly important that the abruptly described movement sequence from the situation according to FIG. 5 to that according to FIG. 6 cannot be influenced by the actuating element 10, i.e. "creeping" contact closure is not possible. On the other hand, the tensioning of the spring 14 and subsequently its suddenly decreasing resistance on the actuating member can be felt in the desired manner.

The switch-on position is maintained in that the toggle lever 10, 50 has passed its dead center in this position and the ratchet lever 40 is under the action of the contact spring 23 (which is bent slightly to generate the contact pressure).

Since the switch often remains in the switched-on position for a long time, it is advantageous if the "spring" 14 is as little or as little as possible in the switched-on position at least not much more than is loaded in the off position. Otherwise, it could slow down over time. As can be seen from FIG. 6, the guide 15 (link) for the articulation axis 51 in the switched-on position is practically perpendicular to the direction of the leg 50 or in any case at such an angle that the force component of the force exerted by the leg 50 in the longitudinal direction of the guide is considerable is less than the force component perpendicular to the guide; As a result, the spiral spring 14 experiences only a small permanent load in the switched-on position as desired. This arrangement is possible because it is provided for guidance or link 15 in the actuator 10 and moves with it.

Since the spring 14 is not significantly loaded neither in the switched-off nor in the switched-on state, it is possible to design it from plastic. This in turn opens up the possibility of integrally molding them on the actuator 10 and producing the actuator 10 and spring 14, for example, as a one-piece plastic injection molded part. With a further advantage, one part (namely the spring) is saved in terms of assembly technology, as a result of which the switch lock of the device circuit breaker according to the invention only consists of the three parts of the actuating member, U-bracket and latch lever. This corresponds to the absolute minimum of parts with which the multiple requirements explained at the beginning, such as jump switching on and off, free tripping and forced tripping, can be realized.

The following also applies to the sequence of movements when switching on: in addition to the link 25 with the catch 26, the carrier 20 has a further link or guide 27, in which a pin 44 of the ratchet lever 40 slidably engages. As a result, the pawl lever 40 is guided against displacement in its longitudinal direction with respect to the fixed link 25. Such longitudinal displacements could otherwise occur because of the sliding movements of the end 52 in the elongated hole 43 (compare FIGS. 3 to 6) and then influence the contact point of the latch edge 46 on the latch surface 63, as a result of which the set trigger values of the circuit breaker would change.

In the switched-on state (FIG. 2), the rocker spring 12 is tensioned and acts in the counterclockwise direction on the rocker 10, but it cannot overcome the locking of the toggle lever 10, 50 as long as the latch lever 40 locks on the release latch 62 in the position shown and is loaded by the force of the contact spring 23. However, as soon as the release lever 60 is pivoted to a sufficient extent by a monitoring device (arrow A in FIG. 2), the latch edge 46 slides off the latch surface 63, as a result of which the aforementioned locking of the toggle lever is suddenly eliminated. On the one hand, the spring 12 pivots the actuator 10 back into the switched-off position, and on the other hand the contact arm 41 of the ratchet lever is free to be pivoted upwards by the contact spring 23, the contacts opening suddenly.

The contacts open suddenly, even if the actuating element is blocked in the switch-on position during automatic triggering (free triggering). The toggle lever 10, 50 then remains in the position according to FIG. 2, but the ratchet lever pivots about the end 52 of the leg 50.

Even when switching off by manual actuation of the rocker 10, the contacts are suddenly opened (switch-off jump), by suitable action on the release lever 60 or the release pawl 62 from the actuating member 10, as will be explained below with reference to FIGS. 1 and 2 is explained with FIG. 7. On the actuating element 10 there is a switch-off element 16 in the form of an arm 16 which projects approximately radially with respect to the axis 11, and on the upper end of the release pawl 62 there is a cam 64 which projects laterally molded on, which is located in the pivoting range of the free end of the arm 16. The cam 64 has a first inclined surface 64 'and a second inclined surface 64˝ (Fig. 7). During the switch-on movement of the actuating member 10, the arm 16, starting from the rest position 16a (FIG. 7), is resiliently deflected along the inclined surface 64 'into an intermediate position 16z, but then springs back into the position 16e, whereby it in the switch-on position (FIG 2) is located under the cam 64 next to the release pawl. When switching off manually, the arm 16 is pivoted with the actuating member, whereby it slides upward on the inclined surface 64˝ and thereby deflects the release pawl 62 in a clockwise direction. As a result, the switch is inevitably triggered suddenly, as described above in connection with the automatic triggering. It should be noted that even with a slow switch-off movement and correspondingly "creeping" deflection of the release pawl 62, the contact pressure does not decrease correspondingly, but initially increases somewhat, because at the same time the toggle lever 10, 50 is completely out of the slightly bent switch-on position according to FIG. 2 is stretched until the dead center is overcome.

Regarding the switch-on movement, the following should also be mentioned: The geometric arrangement is preferably chosen such that during the movement section in which the arm 16 slides down over the inclined surface 64 'and is deflected by the cam 64, the downward movement is practically radial to the pivot axis of the Release lever 60 is directed. This prevents the trigger pawl from experiencing a pivoting moment when switched on by the arm 16, which in turn could impair the triggering accuracy (while the arm 16 is deflected resiliently, the pawl edge 46 already lies on the pawl surface 63).

The cam 64 at the end of the release pawl 62 also overlaps an extension 47 on the pawl lever which extends beyond the pawl edge 46. This limits the path by which the latch arm 42 can lift upwards. A cam 45 is then formed on the contact arm 41 of the ratchet lever and engages under the contact spring 23. With this design, it is ensured that the contacts can be separated both after automatic triggering and after manual switching off by action on the actuating member 10 (positive opening) if they should stick to one another and the force of the tensioned contact spring 23 should not be sufficient for the contact separation.

The present circuit breaker is also particularly suitable for actuating an auxiliary contact unit arranged outside the switch, as will be described below. Auxiliary contacts are used for signal or control purposes and should always change their switch position at the same time as the contacts of the circuit breaker, regardless of whether the circuit breaker is actuated manually or automatically.

8 and 9, an auxiliary contact unit 70 is shown schematically, which is preferably mounted laterally outside the switch housing 2 on the circuit breaker according to FIGS. 1 and 2. The auxiliary contact unit 70 contains two changeover contacts, which are actuated simultaneously. A movable contact on the contact spring 73 or 73 'works with two fixed contacts 72, 74 or 72' and 74 '. The switch position according to FIG. 8 corresponds to the switch-off position of the circuit breaker according to FIG. 1 and the switch position according to FIG. 9 corresponds to its switch-on position according to FIG. 2.

The contact arrangement of the auxiliary contact unit 70 and its actuating mechanism are arranged on a common carrier or a base plate 71. The operating mechanism For example, as shown, it can be constructed as follows: A first bracket 76 and a second bracket 83 are each pivotably mounted on the base plate 71 by means of bearing pins 75 and 82, respectively. The first tab 76 in turn supports a two-armed pawl 79 over a pin 78, the pawl arm 81 of which interacts with a shoulder 84 on the second tab 83. A tension spring 86 tends to pivot the first tab 76 upward. Another, on the pin 78 tension spring determines the pivot position of the two-armed pawl 79 to the first tab 76. The second tab 83 has two cams 85 and 85 'for driving the contact spring 73 and 73'.

To actuate the auxiliary contact unit 70, a control cam 18 "rising" with respect to the rocker axis 11 is provided on the rocker 10 of the circuit breaker. A cam 77 projecting laterally from the first tab 76 of the unit 70 protrudes into the switch housing 2 and is located in the area of the control cam 18 (the position of the rocker axis 11 and the control cam 18 are indicated by dash-dotted lines in FIGS. 8 and 9, as are those Location of the actuating cam 77 in FIGS. 1 and 2). If the circuit breaker is switched on by pivoting the rocker 10, the curve 18 presses the cam 77 downward, the latch arm 81 taking along the second tab 83 via the shoulder 84, which in turn brings the contact springs into the switch position according to FIG. 9. The course of the curve 18 is chosen with respect to the direction of movement of the cam 77 so that neither the tension spring 86 nor the contact spring 73 and 73 'in the switched-on position exert a disturbing torque on the rocker 10. When the rocker 10 is pivoted back into the switch-off position - by hand or as a result of automatic switch activation - the cam 77 also follows the curve 18, as a result of which the auxiliary contact unit again assumes the position shown in FIG. 8.

The following measure ensures that even if the circuit breaker is tripped (if the rocker 10 automatically tripped in the switch-on position according to Fig. 2 remains blocked), the auxiliary contact device 70 is automatically unlocked and its contacts go into the position shown in FIG. 8 at the same time as the circuit breaker contacts open: a pawl 80 protrudes from the pawl 79, which projects laterally into the housing 2 of the circuit breaker and is in the range of motion of the contact arm 41 of the ratchet lever 40; preferably a cam 48 is formed on the end of the arm 41 for cooperation with the trigger cam 80. During normal switching on and off, as well as with normal automatic triggering of the circuit breaker, there is an interaction between cams 80 and 48. In the case of the free release mentioned, however, the latch lever with the cam 48 pushes the release cam 80 upward because the actuating mechanism of the auxiliary contact unit via the cam 18 and the cam 77 initially remains in the position according to FIG. 9. The two-armed pawl is thus pivoted by the cam 48 so that it releases the tab 83 and the contact springs 73, 73 'can pivot upwards. By (as can be seen from FIGS. 2 and 9) the tripping cam 80 in the switched-on position is at a distance from the cam 48 of the arm 41, it is ensured that the sudden opening of the circuit breaker contacts is not impeded by the tripping mechanism of the auxiliary contact unit.

The device circuit breaker described according to FIGS. 1 and 2 could in principle be implemented with an actuating element for sliding movement or in the form of a push button instead of with a pivotable rocker 10. The switch is characterized by a long service life and functional reliability in all switching and triggering processes. In comparison with known constructions, in which the switching on and off does not take place suddenly, no additional parts are required. The switch shown is also particularly suitable for automatic assembly, since the parts are joined together practically in only two directions (in the plane of the drawing in FIGS. 1 and 2 and perpendicularly thereto). As a result, the switch is ideal for efficient, high-volume production.

Claims (11)

1. Protective switch with a single-pole or multi-pole contact arrangement (21, 22), with a rotatably mounted actuating member (10) movable manually between a switch-on and a switch-off position, with a further toggle-lever leg (50) forming a toggle lever with the actuating member as a first toggle-lever leg, and with a two-armed pawl lever (4) for transmitting movement between the actuating member and contact arrangement,

   - the pawl lever (40) cooperating by means of a contact arm (41) with the contact arrangement and by means of a tripping arm (42) with the tripping pawl (62) of an overcurrent and/or undervoltage monitoring device and being supported pivotably between these at the end (52) of the further toggle-lever leg (50),

   - the first toggle-lever leg formed by the actuating member (10) being capable of being shortened, counter to the effect of a spring, in terms of its length defined by the distance between the toggle-lever joint axle (51) and the rotary axle (11) of the actuating member, in that the toggle-lever joint axle (51) is fixed to the further toggle-lever leg (50) and is guided displaceably, counter to the effect of a spring, in a first slot (15) extending in the actuating member (10) at a variable distance from the said rotary axle (11),

   - the said end (52) of the further toggle-lever leg (50) carrying an axle journal (52) which is guided in a stationary further slot (25) controlling the switch-on movement of the pawl lever (40),

   - there being provided, in an intermediate position of the pawl lever (40), an engagement of the axle journal (52) in the further slot (25) during the switch-on movement, at least until the dead-centre position of the toggle lever (10, 50) is reached, and

   - there being provided a spring which, during the switch-on movement, while the axle journal (52) is engaged, is tensioned and which, after the release of the engagement, brings about an abrupt contact-closing as a result of at least partial expansion,
   characterized

   - in that the further toggle-lever leg (50) is constant in terms of its length defined by the distance between the toggle-lever joint axle (51) and the axle journal (52),

   - in that only a single spring (14) supported on the actuating member (10) is provided for loading the toggle-lever joint axle (51) and for bringing about the abrupt contact-closing,

   - in that the axle journal (52) is held in the further slot (25) during the switch-on movement solely by bearing on a notch (26) which is formed in the slot and from which it slides off automatically approximately in the region of the dead-centre position of the toggle lever (10, 50).
2. Protective switch according to Claim 1, characterized in that the further toggle-lever leg (50), the toggle-lever joint axle (51) and the axle journal (52) are formed by a U-shaped shackle.
3. Protective switch according to Claim 1 or 2, characterized in that the axle journal (25) also engages into a long hole 43 located in the pawl lever (40) and extending approximately in the longitudinal direction of the latter.
4. Protective switch according to one of Claims 1 to 3, characterized in that the pawl lever (40) is guided against displacement in its longitudinal direction in relation to the stationary slot (25).
5. Protective switch according to one of Claims 1 to 4, characterized in that, in the switch-on position, the spring (14) is relieved and is formed on the actuating member, preferably as a leaf spring.
6. Protective switch according to one of Claims 1 to 5, characterized in that, in the switch-on position of the actuating member (10), the first slot (15) formed in the latter is directed relative to a force exerted on it by the further toggle-lever leg (50), in such a way that the force component in the longitudinal direction of the slot (15) is lower than the force component perpendicular to the slot (15).
7. Protective switch according to Claim 1, characterized by a switch-off member (16) which is connected to the actuating member (10) and cooperates with the tripping pawl (62) mounted pivotably about an axle (61) and which, as a result of the switch-on movement of the actuating member (10), comes into a position engaging over the tripping pawl (62) and, during the switch-off movement, pivots the tripping pawl (62) into a tripping position releasing the pawl lever (40).
8. Protective switch according to Claim 7, characterized in that the movement of the switch-off member (16) in relation to the tripping pawl (62) is directed essentially radially relative to the pivot axle (61) of the tripping pawl, so that, during switch-on, the latter experiences no moment in the tripping direction.
9. Protective switch according to Claim 1, characterized in that there is on the tripping pawl (62) a boss (64) which engages over the respective arm (42) of the pawl lever (40) on the side located opposite the pawl face (63) of the tripping lever (62), in order to ensure a forced opening of the contacts (21, 22) by means of the pawl lever (40).
10. Protective switch according to Claim 1, characterized in that its actuating member (10) has a control cam (18) for the actuation of an auxiliary-contact unit (70) arranged outside the protective switch, an actuating boss (77) which belongs to the actuating mechanism (76, 79, 83) of the auxiliary-contact unit (70) projecting into the interior of the protective switch in the range of movement of the said control cam (18).
11. Protective switch according to Claim 10, characterized in that there is located in the range of movement of the contact arm (41) of the pawl lever (40) a tripping boss (80) which belongs to the actuating mechanism of the auxiliary-contact unit (70) and which, in the switch-on position, assumes a distance from the said contact arm (41).

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