NO167612B - MANUAL ELECTRIC SWITCH. - Google Patents

Abstract

The invention relates to a manually-operated circuit breaker (1) having a two-armed switch lever (9) supported such that it can pivot on the switch housing. Its drive arm (24) together with a push rod (11) form the guide of a bell crank (25) in kinematic drive terms. A contact link (13) connects two fixed contacts (14, 15). The pivoting movement of the switch lever produces a follow-through movement of the bell crank (25) through its extended position against a contact spring pressure, which allows the contact link (13) to be transferred into a contact open position, and vice versa. The push rod (11) is inserted such that it can pivot with an end remote from the contact (guide end 26) in a guide slot (27) running in its pivoting direction on the unsupported end of the drive arm (24) of the switch lever (9), and such that it can move in the slot direction. Between its ends, the push rod is provided with a latching tab (34) which, after a follow- through movement of the push rod (11) in the contact open direction, through the bell crank extended position under the contact spring force of the contact link (13) in the open position, is located in a stop position on a latch projection (35) fixed to the housing and holds the contact link (13) in the contact open position. <IMAGE>

Description

The present invention relates to a manual, electric switch as stated in the introductory part of claim 1.

Such switches are known, e.g. from EP-A-0127784. They comprise a two-stage switch lever which is rotatably stored in the switch housing and which, by swinging between a closed and an open position, causes a contact bridge to be opened or closed. The contact bridge is moved kinematically by means of an angle arm consisting of a drive arm which is connected to the switch lever and a pressure-cam follower which is stored in a rotary-push joint on the drive arm. The pressure camber serves as a pressure transfer part and affects the contact bridge with its free end.

When the switch lever is moved from the engagement position to the disengagement position, the angle arm will be pushed through its extended position. The articulated shaft of the angle arm is thereby moved downwards in the direction of the contact bridge. Through the pressure cam follower, the contact bridge opens downwards. The angle arm is then in an over-extended end position in which it is held by the contact spring pressure.

By turning the switch lever in the opposite direction, the angle arm will be brought from its overstretched position to its normal bending zone. As the pressure-cam follower can be moved freely in the drive arm's rotary-push joint in the switch lever, the angle arm will be transferred impact-wise to the break position under the influence of the contact spring, whereby the contact bridge is closed.

A disadvantage of this type of switch is the large number of individual parts and joint connections that are required. During torque switching, these parts must also be accelerated, whereby the switching speed is reduced. It is therefore an object of the invention to produce a manual switch of the above-mentioned type which is simply constructed and where the switch lever can be operated without affecting the torque switching.

This has been achieved as stated in the characterizing part of claim 1. When the pressure cam follower is locked against the contact housing side in the contact opening position, it will in this position function exclusively as a distance element which maintains the contact bridge at a certain distance from the fixed contacts.

By swinging the contact lever to the closed position, the bolt tongue is brought out of engagement with the bolt cam. After exceeding the angle arm extension position in the contact closing direction, the pressure cam follower is freely movable in the contact lever. Under the influence of the contact spring pressure, the cam follower together with the contact bridge will be moved strikingly in the contact closing direction. Thereby, an operator-independent torque is ensured. This cannot be prevented either by stopping the contact lever in an undefined middle position. Security has thus been achieved at all times for a defined method of handling. The torque switching can also take place even faster than with known switches, as the masses to be accelerated are smaller. For this reason, greater shearing speeds and greater shearing performance can be achieved. This effect is reinforced by the small, internal frictional forces between the switch mechanism's moving parts, due to the loss of shaft connections.

When the switch is in the locked initial position, the switch lever can be moved through a limited angular sector of approx. 60°. In a structurally advantageous design, the switch according to the invention will only need* one single structural part in addition to the switch lever, namely the pressure cam follower, for operating the contact bridge. This means a significant, construction-wise and production-technical simplification. Material consumption for the switch mechanism has also been reduced in favor of a narrow design of the switch. The switch mechanism's movements all take place in one plane.

According to claim 2, due to the locking of the pressure cam follower in the contact opening position, the switch lever is completely relieved of the contact spring pressure. The switch lever will therefore:,, in normal, vertical installation of the device, fall down in the cut-out end style-1 due to its own weight.

According to the characterizing part of claim 3, the contact spring pressure will force the contact bridge into contact with the end of the pressure cam follower towards the contact side. In this case too, no additional structural elements are needed to ensure a defined position of the pressure cam follower in relation to the contact bridge.

The design feature according to claim 4 prevents deviation in the lateral direction of the end of the pressure cam follower towards the contact side, whereby the pressure transfer between the cam follower and the contact bridge is improved. The two structural parts are thereby fixed in position relative to each other, and during the contact movement the end of the pressure cam follower towards the contact side will exclusively rest against the contact bridge in a narrowly defined surface zone.

At the same end of the cam follower, a longitudinal blind channel is arranged which accommodates a compression spring (claim 5). This serves as a clearance compensation spring in the event that, as a result of length tolerances, the pressure cam follower will not always be safely brought into contact with the contact bridge, particularly in the closed position of the switch. Because of the clearance compensation spring, a pressure transfer between said structural parts will still be possible, by bringing the switch lever to its end position (stop position). Thereby, the switch lever operating arms will align with each other, if several switches according to the invention are arranged in a row, and this gives a visually advantageous overall impression.

Claims 7-9 relate to advantageous modifications of the particularly simple design of the rotary-sliding joint between drive arm and pressure cam follower, which is defined in claim 6. The guide table extends through an angular sector of approx. 90°, which corresponds to the angle of rotation of the switch lever and which is delimited by stop surfaces at the ends of the angle sector respectively in and against the closing direction of rotation. In the following, the impact floats are referred to as the cut-out or cut-in edge. The meaning of these designations will appear from the figure description. The guide table's angular sector is located directly opposite the switch lever's operating arm. As the pivoting axis of the switch lever is situated roughly in line with the outer wall that encloses the switch lever, this ensures that the guide table will be inside the switch housing in any operating position of the switch lever. Consequently, no foreign bodies, contaminants or the like can penetrate the guide table, hindering the function of the switch. The internal, moving parts of the switch mechanism are also covered in all positions of the switch lever, and thereby protected against manipulation, soiling or the like.

In the switch-on position, according to claim 10, the contact spring force will be transmitted through the pressure cam follower to the switch lever, which is thereby fixed in its defined switch-on swing position. At the same time, it is prevented that the guiding ability of the pressure cam follower is pushed out of the guiding groove with consequent disruption of the switch's operation. It is particularly advantageous if the length of the pressure cam follower is somewhat smaller than the distance between the contact bromide and the disconnection surface in the contact closed position, as stated in the characterizing part of claim 11. With such a construction, it will be ensured at all times that the contact bridge is located against the two fixed contacts in the closed position, despite existing manufacturing tolerances in connection with the length of the pressure cam follower. If the length of the cam follower was greater than this distance, the contact bridge, in the closed position, would therefore not rest properly against the counter contact. The clearance equalization is thereby taken over by the compensation spring at the end of the pressure cam follower towards the contact side.

According to claim 12, the switch lever is movable in relation to the pressure cam follower, without a force being exerted against it. The cam follower itself thereby remains in its locked open position, which advantageously cannot be canceled by fleeting or insufficient turning of the switch lever. Incorrect operation of the manual safety switch is thereby effectively prevented.

Claims 13 and 14 describe precautions which will lead to a reduction of the internal wear in the switch mechanism and ensure a defined switch kinematics also when the switch is used for a longer period of time. The guide table's stop surfaces and likewise the disconnection and connection flanks are of a bearing bowl-like design, and the pressure cam follower's guiding ability has a correspondingly vaulted, convex shape. Large contact surfaces are thereby created between the pressure cam follower's guiding ability and the guiding table. There are no point contact points that would be exposed to large forces with consequent increased wear.

In claim 15, a construction feature is specified which will provide an improved engagement of the pressure cam follower in its open position. The superimposed engagement surfaces on the bolt tongue and the bolt cam, respectively, extend in relation to the cam follower length axis at an acute angle with an angular opening in the contact closing direction. The thrust cam follower's bolt tongue is thereby brought into engagement behind a bolt cam on the inner part of the contact housing. The interlocking cannot be canceled by simple lateral movement, but the cam follower must make a combined movement in longitudinal and lateral direction.

The invention is described in more detail below with reference to the accompanying drawings, in which: Fig. 1 shows a side view of a safety switch in the closed position, with the switch housing open. Fig. 2 shows a side view of the switch according to fig. 1 in open position. Fig. 3 shows an enlarged, schematic view of the switch mechanism in different switch positions. Figs 1 and 2 show the switch mechanism in the safety switch 1, whose plastic switch housing is largely square-shaped and composed of two switch housing half-shells 1 2. On each side of the switch housing, there are arranged two mutually opposite contact terminals 3. The connecting wires are introduced to the contact terminals 3 through switch housing openings 4, and fixed with clamping screws 5.

The space between the two contact terminals is occupied by a shaft 6 for a fuse insert 7 which can be inserted from above, and the switch mechanism for manual operation of the safety switch 1. The position directions for the contact terminals 3, the shaft 6 and the switch mechanism 8 thereby run approximately parallel to each other in the same plane, and the switch according to the invention is also of a very narrow construction.

The switch mechanism 8 consists of the switch lever 9 which, by a switch housing projection 10 which is arranged on the upper side of the safety switch 1, is rotatably supported on a pivot pin 42, of the pressure cam follower 11 which extends largely perpendicular to the switch housing upper side and of the contact bridge 13 which is affected by the cam the follower towards the contact closing direction 12. With the help of the contact bridge 13, the created current path through the safety switch 1 can be interrupted manually. The current path runs between the first side contact terminal 3, through the first fixed contact 14, the contact bridge 13, the second fixed contact 15, the foot contact 16 for the fuse insert 7, the fuse insert 7 itself and through the head contact 17 of the insert to the second contact terminal 3 marked.

Between the shaft 6 for the fuse insert 7 and the switch mechanism 8, a latch mechanism 18 is also arranged which prevents the contact bridge 13 from closing if the fuse insert 7 is not inserted. The operation of the mechanism is known from EP-A-0184652.

The construction and kinematics of the switch mechanism 8 are described below in connection with fig. 3. Switch lever 9

which, rotatable in the main plane of the safety switch 1, is supported by the switch housing projection 10, is two-armed. The outer operating arm 19 serves as a handle and in the closed position (fig. 1) will cover the screw cap 20 for the fuse insert 7. The operating arm 19 is largely L-shaped, and the pivot bearing branch 21 passes into a cylinder roller 22 which serves as switch lever bearing part. In the pivot bearing branch 21, a spring-loaded flexure joint 23 is also fitted which is to protect the switch from being closed by force when the fuse protection insert 7 is not inserted and locked to the switch lever 9. The construction and function are likewise described in EP-A-0184652.

The part of the cylinder roller 22 which is facing away from the operating area 19 forms the drive arm 24 for the pressure cam follower 11. These two parts form the drive kinematic control means for an angle arm 25 which, by its bending or stretching movement, brings the contact bridge 13 into the closed and open positions, respectively. The knee joint 25 of the angle arm is a rotary-sliding joint. It is created by the fact that the pressure cam follower 11's guiding ability 26 towards the knee joint side is located in a guiding groove 27 which, at the free and unsupported end of the switch lever 9's drive arm 24, extends in a circular arc-shaped curvature about the pivot axis 42 in the direction of rotation of the lever 3 6. Furthermore the guide end 26 of the pressure cam follower 11 is rotatably and displaceably supported in the longitudinal direction of the track by the drive arm 24.

The guide track 27, which extends in the form of a circular arc in the swing plane of the switch lever 9, runs through a circular sector of approx. 90°, roughly corresponding to the angle of rotation of the switch lever 9, and is bounded at both ends by two abutment surfaces, namely a disengagement flank 37 and a disengagement flank 40. The guide groove 27 is located directly opposite the switch lever 9's operating arm 19. In the longitudinal direction, the guide groove 27 is undercut approximately in the form of a trough.

The pressure cam follower 11 extends from the drive arm 24 of the switch lever 9 approximately in contact with the closing direction 12 in the interior of the switch. Its end 28 towards the contact side extends between the contact location's 2 fixed contacts 14 and 15 and affects the contact bridge 13 in the contact closing direction 12. Through the two contact springs 30 which are supported against the switch housing bottom 29, the contact bridge 13 is permanently spring-loaded in the contact closing direction 12. This ensures safety for a constant, mutual contact between the end 28 of the pressure cam follower 11 towards the contact side and the middle part of the contact bridge 13. At the end 28 of the pressure cam follower 11 towards the contact side, there are, largely perpendicular to the joint plane of the angle arm 25, arranged two protruding guide pins 31 which each engages in a guide recess 33 directly above in the switch housing inner wall 32, which extends in the contact closing direction 12 of the contact bridge 13. The end 28 towards the contact side is thus fixed in the lateral direction and can only be moved in the contact closing direction 12 in the switch housing.

Between its two ends, the pressure cam follower 11 is equipped with a rack tongue 34 which is arranged in the lateral direction largely in the plane of the angle arm and which, after the pressure cam follower 11 has been guided through the angle arm stretching position under the contact spring pressure from the contact bridge 13 which is in the open position, will be in contact in ans lagsst illing against a bolt cam 35 which is firmly connected to the switch housing. The overlapping engagement surfaces of the bolt tongue 34 and the bolt cam 35 extend, in relation to the longitudinal axis of the cam follower, at an acute angle 41 with an angular opening in the contact closing direction 12. The pressure cam follower 11 is thereby brought into secure engagement.

The coupling kinematic process is shown in fig. 3. When the switch 1 is brought to the closed position (fig. 3a), the angle arm 25, consisting of the drive arm 24 and the pressure cam follower 11, will be in its maximum bending position. In this position, the guide capability 26 of the cam follower lies in the guide table 27, in abutment against the disengagement flank 37 which delimits the slot in the closing swing direction 36 of the switch lever 9. Due to the spring load from the contact springs 30, the switch contact through the fixed contact 14, the contact bridge 13 and the fixed contact 15 is reliably closed. As the length of the pressure cam follower 11 must not exceed the distance between the contact surface 37 and the center of the contact bridge, a length which is somewhat smaller than this critical distance has been chosen, as security against manufacturing tolerances. In order to compensate for the clearance that arises therefrom, a blind channel 38 is arranged in the end part 28 of the pressure cam follower 11 towards the contact side, which accommodates the clearance compensation spring 39. In closed style1 none as shown in fig. 3a, this clearance compensation spring 3 9 abuts against the contact bridge 13, forces the cam follower 11 upwards and thereby brings the switch lever 9 into the shown, defined closed position end position. For the purpose of safe contact establishment, the force from the clearance compensation spring 39 must be less than the force from the contact springs 30.

The switch is opened by turning the switch lever 9 in the clockwise direction. By means of the disengagement flank 37, which is named as such because it loads the pressure cam follower 11 during the disengagement movement, the guide ability 26 of the pressure cam follower 11 and thus the cam follower itself is pushed downwards in the direction towards the contact closing direction 12, whereby the contact bridge 13 is separated from fixed contact with 14 and 15. This movement continues until the angle arm 25's extended position is reached (switch lever 9 shown with solid lines in fig. 3b). After the dead center of the angle arm 25 has been exceeded, the pressure cam follower 11 is moved slidingly in the guide groove 27 in the contact closing direction under the influence of the spring force from the contact springs 30. Due to the simultaneous movement in the lateral direction, however, the bolt tongue 34 will be brought into engagement with the bolt cam 35 in the switch housing, whereby pressure - the cam follower 11 and thus the contact bridge 13 is fixed in the open position (fig. 3c). The guiding ability 26 of the pressure cam follower 11 will thereby be located approximately in the middle part of the guiding groove 27. The switch lever 9 is thus freely movable between the maximum open position as shown in fig. 3c, and the approximate middle position as shown in fig. 3b, without canceling the engagement between the pressure cam follower and the bolt cam 35.

The bolt connection between the bolt tongue 34 and the cam 35 also serves to alternately change the function of the pressure cam follower 11. During the switch mechanism's contact opening movement, the cam follower 11 functions as a control device for an angle arm 25, consisting of the drive arm 24, the disconnection flank 37 at the guide table 27 and the guiding ability 26 as a knee joint, and the pressure cam follower 11. In the contact opening position, the pressure cam follower 11 is detached from the drive arm 24 as a result of the engaging connection , and the cam follower thus only serves as an avs tooth element..

When turning the switch lever 9 in the opposite direction, to close the safety switch 1, the switch lever 9 will first cover the above-mentioned free path. The engagement flank 40 of the switch lever 9, which delimits the guide table 27 towards the closing direction 36 for the switch lever 9, is then forced against the pressure cam follower

11 guiding ability 26. With a combined movement in the longitudinal and lateral direction, the interlocking of the bolt tongue 34 and the bolt cam 35 is cancelled. The pressure cam follower 11 thereby once again serves as a control device for the angle arm 25. However, this has changed, as the control surface of the drive arm 24 at the switch lever forms the knee joint together with the engagement flank 40. However, the knee joint shaft is no longer located in the bearing recess of the disengagement flank 37, but in the recess in the engagement flank 40.

Just after the intervention has been cancelled, the angle arm's extended position is reestablished (fig. 3b, where the switch lever 9 is shown with broken lines). After the bottom dead center of the angle arm 24 has been exceeded, the pressure cam follower 11 is displaced percussively in the contact closing direction 12 by means of the contact springs 30, whereby the contact is closed. Since the guiding ability 26 can thereby slide freely in the nearest leading track 27, it is only necessary to accelerate the contact bridge 13 and the pressure cam follower 11, in order to close the contact. This results in a very fast torque engagement which is also not hindered by the switch lever 9.

In order to reduce friction, the abutment floats 37 and 41 are designed approximately like bearing cups, while the guide end 26 of the pressure cam follower 11 is vaulted convex.

Claims (15)

1. Manual, electric switch (1) with a two-arm switch lever (9) which is pivotably supported on a switch housing, and with a pressure cam follower (11) whose guide end (26) is mounted with a lever drive arm (24), and which is pivotable about an axis parallel to the lever driver axis (42) and limited displaceable approximately in the direction of swing of the driver arm (24), where the lever driver arm (24), together with the pressure cam follower (11), forms the drive kinematic control part in an angle arm (25), and where the switch includes a contact bridge (13) which, when the angle arm (250, by turning the switch lever (9), is guided by the pressure cam follower (11) over its range of motion, under counteraction of the pressure force from a contact spring (30), can be returned from a contact closing position to a contact opening position , characterized by that the pressure cam follower (11) between its ends, i.e. a guide end (26), and a contact side end (28), is equipped with a bolt tongue (34) which, when the pressure cam follower (11) is guided over the angle arm's ( 25) range of motion while the contact bridge (13) is held in the open position under the counteraction of the compressive force from the contact spring (30), is brought into engagement behind a fixed latch cam (35) in the switch housing and in this engagement position the contact bridge (13) remains in the contact opening position and which, when turning the switch lever (9) in the closing direction (36) is released from the engaged position, and that the contact bridge (13) which, without being hindered by the switch lever (9), is closed under the influence of the contact spring pressure after the angle arm (25)'s range of motion in the closing direction has been exceeded ( 36), is pushed back in its closed position. 2. Breaker in accordance with claim 1, characterized by that the switch lever (9) is relieved of the contact spring pressure when the pressure cam follower (11) is brought into engagement position. 3. Breaker in accordance with claim 1 or 2, characterized by that the contact bridge (13) rests against the contact side end (28) of the pressure cam follower (11) under the influence of the contact spring pressure. 4. Breaker in accordance with claim 3, characterized by that at the contact side end (28) of the pressure cam follower (11) there is arranged, on one or both sides, a guide pin (31) which projects largely perpendicularly from the plane of movement of the angle arm (25) and which is inserted in the contact closing direction (12 ) in a guide recess (3 3) which is arranged in the opposite switch housing inner wall (32) and extends in the contact closing direction (12) of the contact bridge (13). 5. Breaker in accordance with claim 4, characterized by that a longitudinal blind channel (38) is arranged in the contact side end (28) of the pressure cam follower (11) which accommodates a pressure spring (39). 6. Breaker in accordance with claim 1, characterized by that the guide end (26) of the pressure cam follower (11) farthest from the contacts is inserted rotatably and displaceably in the direction of the track in a guide track (27) at the unsupported end of the switch lever (9) drive arm (24). 7. Breaker in accordance with claim 6, characterized by that the longitudinal axis of the guide groove (27) for the guide end (26) of the pressure cam follower (11) extends in the form of a circular arc around the pivot axis (42) of the switch lever (9) in its pivot plane. 8. Breaker in accordance with claim 7, characterized by that the guide groove (27) extends through an angle sector corresponding to the angle of rotation of the switch lever (9), and is bounded respectively in and towards the closing direction (36) by end-stop surfaces, respectively disconnection flank (37) and engagement flank (40). 9. Breaker in accordance with claim 8, characterized by that the guide groove (27) is located directly opposite the operating arm (19) of the switch lever (9). 10. Breaks in accordance with one of the preceding requirements, characterized by that the guide end (26) of the pressure cam follower (11) rests against the disconnection flank (37) which delimits the guide groove (27) in the closing direction (36) of the switch lever (9), when the switch lever (9) is in the closed position. 11. Breaker in accordance with claim 10, characterized by that the pressure cam follower (11) length is somewhat smaller than the distance, measured in the contact closing direction, between the contact bridge center and the disconnection flank (37) which delimits the guide track (27) in the closing direction (36). 12. Breaks in accordance with one of the preceding requirements, characterized by that the guide end (26) of the pressure cam follower (11) takes a position at a distance from the engagement flank (40) and disengagement flank (37) of the guide groove (27), when the switch lever (9) is in the open position. 13. Switch in accordance with one of the claims 10-12, characterized by that the disengagement flank (37) and/or engagement flank (40) of the guide track (27) is of a bearing bowl-like design. 14. Breaks in accordance with one of the preceding requirements, characterized by that the guide end (26) of the pressure cam follower (11) is of a vaulted, convex shape. 15. Breaks in accordance with one of the preceding requirements, characterized by that the overlapping engagement surfaces of the bolt tongue (34) and/or the bolt cam (35) form an acute angle (41) with the cam follower's (1 1) longitudinal axis, with an angular opening in the contact closing direction (12).