GB2120852A

GB2120852A - A switch for installation in assembly panels

Info

Publication number: GB2120852A
Application number: GB08310397A
Authority: GB
Inventors: Rudolf Hopt
Original assignee: Schuler AG
Current assignee: Schuler AG
Priority date: 1982-04-17
Filing date: 1983-04-18
Publication date: 1983-12-07
Also published as: DE3214241A1; JPS58197613A; FR2525385A1; GB8310397D0; DE3214241C2

Abstract

An electric switch, for installation in assembly panels, comprises contacts 30 which are movable relative to fixed contacts 23,24 by a manually operable actuating key 53 which is movable in a switch case 1 against the action of a spring 41 and which comprises an indicating element 58. <IMAGE>

Description

SPECIFICATION A switch, in particular for installation in assembly panels The present invention relates to a switch, in particularfor installation in assembly panels, comprising a key element moveable within a switch case, for manual operation of the switch, and a contact system with fixed and moveable contact elements.

The known switches of this type, in which the key element performs a stroke along the longitudinal axis of the switch against the action of a spring, are provided with a cap portion which can be additionally mounted on the switch and which comprises an additional part arranged in the axis of the key element and serving as holder for and comprising a luminous diode so that when pressure is exerted on the diode the key element arranged in the same axis is simultaneously caused to move so as to operate the switch. The position of the switch is indicated by a corresponding luminous signal emitted by the diode.It is a drawback of this known arrangement that special electric connections must be realized between the diode and the additional part and that such additional parts supplementing the switch require certain addional installation work, beyond that required for the installation of the switch itself.

Finally, the space requirements of such an additional part are often felt to be a disadvantage.

Now, it is the object of the present invention to eliminate this disadvantage.

According to the present invention, this object is solved in that the key element itself comprises an indicating element, i.e. that the indicating element is integrated in the key element and, thus, in the switch.

This facilitates considerably the installation of a switch whose position is indicated by a luminous signal, into a panel or the like. In addition, this offers the possibility to integrate also the connection lines of the indicating element in the switch, according to one embodiment of the invention and, according to another embodiment of the invention, to provide a contact pin for the connection line in the base of the switch.

In one embodiment of the invention, the indicating element consists of a diode operable in two emission colours. According to a further improvement of this embodiment, the emission colour of the diode is indicative of the position of the switch.

In one embodiment of the invention, the indicating element is arranged on the outward, i.e. the operator's end of a key element. And according to another embodiment of the invention, the indicating element may project beyond the upper edge of the key element so that in the case of a diode operable with different emission colours the colour gets clearly visible. In this case in particular it may be convenient to provide the indicating element with a transparent protective cap. In one embodiment of the invention, this protection can be achieved also by a short tube section encircling the indication element.

In one embodiment of the invention in which the key element (push-button) is urged outwardly in the conventional mannerby a spring, the diameter of the indicating element is smaller than the diameter of the key element so that the operator's end of the key element exhibits around the indicating element an annular end face which is urged by the spring against the inner face of the switch case. As a result thereof, the inner space of the switch case is sealed off against the outside in the inoperative position of the key element, a feature which is generally missing in known switches using a cylindrical key element.

According to certain embodiments of the invention, a contact pin for at least one connection of the indicating element is fixed in the base of the switch, while in the known switch comprising an indicating element in the cap portion, the connection point for the indicating element must first be determined and found in the grid plate.

This embodiment of the invention can be further improved in that contact pins provided for realizing the connection of the indicating element, have a length greater than the contact pins leading to the switching contacts so that these extensions of the contact pins are connected with electric lines leading to the connections of the indicating elements.

A further improvement of this embodiment can be achieved by an arrangement in which the key element containing the indicating element comprises bores which are engaged by extensions of contact pins and that a spiral spring of an electrically conductive material is arranged at the end of the contact pin facing the indicating element and has its end opposite the contact pin in contact with connection lines for the indicating element.

In certain embodiments of the invention, finally, electric lines leading to connections of an indicating element may form mechanical guides for the key element. Such mechanical guides may for instance be formed by the extensions of the contact pins.

The switch of the invention will be described hereafter and is shown in the drawing.

In the drawing which illustrates one embodiment of the invention Figure 1 shows an overall view of one embodi mentoftheswitch of the invention; Figure 2 shows an explosion view of the same embodiment, and Figure 3 shows a cross-section through the embodiment shown in Figure 2, along line Ill-Ill in Figure 2, in enlarged scale.

Figure 1 shows a case bottom 1 of a plastic material for a push-button switch with an outer face 3 tapering downwardly in the form of a truncated cone. The lower end of the said bottom portion is closed by a plane face 4, the upper end by a circular face 5 which forms a common edge 6 with the tapering outer wall portion 3. The case bottom 1 is provided with a medium case portion 10 exhibiting the shape of a hollow cylinder and enclosing a fitting short hollow cylinder 13 made of a plastic material whose upper delimiting face is provided with twelve symmetrically arranged successive faces in the form of saw blade teeth 15 and which projects upwardly in the case center portion 10, beyond the case bottom portion 1.

The case bottom 1 comprises a substantially cuboid opening 21 of substantially square outline arranged symmetrically relative to the vertical axis of symmetry 20 of the switch - see Figure 2. The upper plane of this opening coincides with that of the surface 5, while its lower plane intersects a tapering outer wall 3 at about half its height. The side length of the square outline of the opening 21 is approximately equal to the outer radius of the hollow cylinder 13, for instance to twice the grid spacing of a circuit board usually used for electronic circuits. Eight cylindrical contact pins 22 to 25 pass through the case bottom 21, along the vertical edges and the mean perpendiculars of the lateral faces of the substantially cuboid opening 21. The lower ends of these contact pins have a rounded shape, similar to a truncated cone.The upper delimiting faces of the contact pins 22 to 24 are located in the plane of the circular surface 5, while their cylindrical crosssection projects at least partly into the area of the substantially cuboid opening 21 and serves for contact-making.

The contact pins 25 extend upwardly beyond the face5 upto about two-thirds of the height of the medium case portion 10. Contrary to the contact pins 22 to 24, they are enclosed by the plastic material of the case bottom 1 also in the area of the substantially cuboid opening 21, which exhibits in this area semi-cylindrical recesses 27 which extend concentrically to the contact pins 25 and have about twice the radius of the latter. The upper ends of the said contact pins 25 are rounded off at 28 in a form similartotrancated cones. Two moveable contact elements 30 are provided each with two contact bridges 31 in the form of annular springs which are interconnected by a bend 32. The height of the contact bridges 31 is substantially equal to the depth of the opening 21.They consist of a resilient material which may be provided, if necessary, with additional electrically conductive layers or integrally formed strips and have the hollow sides of their connecting bends 32 in contact with the contact pins 23.

Between the contact pins 22/23 and 23/24, respectively, the substantially cuboid opening 21 is provided with protuberances 34 in the form of cylinder segments, to allow the contact bridges 31 to be freely swung into contact with the contact pins 22 or 24, with the pins 23 serving as pivot axis. The free ends of the contact element 30, i.e. those faces of the contact bridges 31 in the form of annular springs which are the closest to the vertical axis of symmetry 20, bear resiliently against lower vertical sides 36 to 38 of an operating element 40 made of an insulating material. The operating element 40 carries on its lower end an elongated actuating element 42 delimited by long parallel faces 36 and lateral faces 37 and 38 extending from the parallel faces at an obtuse angle and forming between them an acute angle.If necessary, the said operating element may be provided at its lower end with a tapering annex not shown in the drawing, which may serve as mounting aid for the assembly of the switch. The height of the lateral faces 36 to 38 and the height of the contact element 30 correspond apprroximately to the depth of the opening 21.

On top of the lower portion of the operating element 40 there is provided a fork-shaped portion comprising a central yoke plate 44 from which two diamatrically opposite prongs 45 extend upwardly.

The prongs 45 have the cross-section of a hollow cylinder segment and are provided at their upper portion with integrally formed pins 48 of cylindrical shape which extend radially outwardly to engage recesses in the hollow-cyindrical vertical wall portion 52 of a key element 53, which recesses serve as operating cams 51. The hollow cylinder has an inner diameter a little larger than the diameter of the operating element 40 so that the prongs 45 of the latter can be received within the key element 53 with only little play. During assembly, the prongs 45 are slightly pressed together in the direction of the vertical axis of symmetry 20 and introduced from below into the key element 53, whereafter the key element 53 and the operating element 40 are turned in opposite directions around their common vertical axis of symmetry until the pins 48 engage the operating cams 51.The area of the key element 53 situated a little above the operating cams 51 takes the form of a solid cylinder 43 delimited on top by a plane annular end face 55 and provided in this area with a circular cylindrical opening 56 intended to receive an indicating element 58, for instance a two-colour luminous diode which may be protected by a cap. The prongs 45 enclose between them a spiral pressure spring 41 the lower end of which bears against the yoke plate 44, while its upper end bears against an annular shoulder or inner end face not shown in the drawing - of the central opening in the key element 53 delimited on top by the solid cylinder 43.

The lower end of the wall 52 of the key element 53 is provided on its outside with a horizontally extending groove 59 receiving in flush arrangement a ring 60 whose outer diameter corresponds to that of the wall 52 and which is vertically cut at one point. The outer face of the ring 60 is equipped with two diametrically opposite, integrally formed cam followers 61 which preferablytaketheform of a right hexagonal prism placed on its vertex whose height is substantially equal or a little greater than the height of the ring 60; the length of the cam followers 61 corresponds to the thickness of the hollow cylinder 13.

The medium case portion 10 is followed on top by a case cover 65 of the upper case portion 2. The cover 65 has the shape of a circular cylinder, an outer diameter corresponding to that of the medium case portion 10 and an inner diamter 67 being a little greater than the outer diameter of the key element 53 on which it is guided. From the lower face of the case cover 65 extends an integrally formed concentrical sleeve 66 whose outer diameter corresponds to the inner diameter of the hollow cylinder 13 and whose inner diameter corresponds to the outer diameter of the key element 53.

The outside of the sleeve 66 is provided with two diametrically opposite cam followers 68 engaging corresponding recesses 70 in the upper portion of the medium case portion 10.

In the lower edge of the said sleeve 66 there are provided, in alternating arrangement, six recesses in the form of saw teeth 72 and six deeper recesses in the form of vertical grooves 73. The latter coact in positive locking engagement with the cam followers 61 and end on the right-hand side in an inclined flank 74 corresponding approximately to the inclined flank of the saw teeth 72. The saw teeth 72 and the grooves 73 are arranged at an angular spacing of about 30 . The contour of the inclined flanks 74 and the saw teeth 72 is substantially mirror-inverted relative to that of the saw teeth 15, but in the assembled switch, the saw teeth 15 are offset against the saw teeth 72 by about half a tooth space.

So, each stroke of the key (along double arrow C) causes the cam followers 61 to move in the same direction, in the embodiment shown in clockwise direction.

The wall 52 of the key element 53 exhibits two diametrically opposite vertical, downwardly open cylindrical bores 76 receiving the contact pins 25 as guides. The cylindrical bores 76 have sufficient room, even when the key element 53 is pressed, to receive spiral springs 78 made of an electrically conductive material and whose upper ends contact connection lines 79 leading in a manner not shown in the drawing within the key element 53 into the recess 56 and to contacts for the indicating element 58 which is likewise not shown in the drawing.

The operating cams 51 in the wall 52 are arranged symetrically relative to the vertical axis of symmetry 20, and the area between the cylindrical bores 76.

Their upper and lower end portions extend vertically, while their middle portion extends at an angle relative to the axis of symmetry 20.

In one of the two stop positions, the spring 41 urges the key element 53 upwardly until the cam followers 61 come to rest against the end of the groove 73. If no cam followers are provided when the switch is designed as key switch, the case cover 65 is provided with an inwardly projecting rim against which the face 55 of the key element 53 comes to rest. In this position, the pins 48 are to be found at the lowermost end of the paraxial lower portion 81 of the cams 51.

When the switch is to be shifted to the other switching position, the user presses down the indicating element 58 and, thus, the key element 53 against the action of the spring 41. This does not change the vertical position of the operating element 40, but causes the pins 48 which project laterally from the operating element 40 to slide upwardly at first in vertical direction along the paraxial cam portion 81, and then in an inclined direction along the inclined portion 82 of the operating cam 51.

Considering, however, that the key element 53 cannot rotate relative to the case 1,2, 10 due to the guiding effect provided by the extended contact pins 25, the operating element 40 turns around the axis of symmetry 20 until the pins 48 enter the upper paraxial portion 83 when the indicating element 58 continues to be pressed. The same turning movement is performed by the actuating element 42 which bears resiliently, preferably by its short sides 38, against the curved ends of the contact bridges 31 of the two contact elements 30 so that these contact bridges 31 come to rest against the contact pins 24 (Figure 2). This entails a wiping movement not only between the contact bridges 31 and the contact pins 24, but also between the connecting bends 32 and the middle contact pins 23. Thus, a good selfcleaning effect is achieved for the contacts.Moreover, it is ensured by the deflection of the contact bridges 31 exhibiting the form of annular springs, provoked by the operating element 40 in its extreme positions that the contact pressure exerted remains always constant, corresponding to the said deflection. The angular distance between the two extreme positions of the operating element 40 is defined by the angular spacing of the two paraxial portions 81 and 83 of the operating cams 51. Considering that the pressure exerted upon the contacts 23 and 24 commences to rise only when the contact element 30 has turned far enough to bring the contact bridge 31 in contact with the contact pin 24, the bouncing of the contacts is also practically eliminated.The contact pressure is determined by the beforementioned angular spacing of the paraxial portions 81 and 83 of the operating cam and the spring tension of the annular spring, and independent of the pressure exerted by the user upon the key element 53. The said pressure does not act upon the contact arrangement, but is transmitted in the lowermost position of the key element 53 via the pins 48, which in this position rest against the upper ends of the upper portions 83 of the operating cams 51, and, thus, via the operating element 40, to the case bottom 1.

In the embodiment of the invention shown in the drawing, the switch is designed as detent switch in which the active switch position is retained by detent means. When performing the downward movement as described before, along arrow C, the detent pins 61 enter the saw teeth 15 of the medium case portion 10 and move downwards to the tooth base, while the ring 60 turns simultaneously by about 15 angular degrees.

Now, when the force acting from above on the indicating element 58 is released, the key element 53 is pressed upwardly by the spring 41, but the cam followers 61 abut against the inclined flanks of the saw teeth 72 in the upper portion 2 and move into the tooth base of the said saw teeth 72, with the ring 60 and the cam followers 61 rotating again about a small angle. The upward movement of the key element 73 is limited by the fact that the cam followers 61 abut against the base of the saw teeth 72, but the dimensions are selected to ensure that in this end position the pins 48 have not yet left the lower end of the upper paraxial portions 83 of the operating cam 51, i.e. that the operating element 40 has not yet performed any rotary movement about the axis of symmetry 20. Accordingly, the switch is still in the position which it occupied in the end position of the key element 53. Any rotary movement of the operating element 53 is prevented by the fact that to this end the pins 48 would have to enter the inclined middle portion 82 of the operating cam 51 which would, however, first require a further upward movement of the key element 53. This is, however, rendered impossible because the cam followers 61 bear against the base of the saw teeth 72. Accordingly, the height of the saw teeth 72 is selected to ensure that the pins 48 do not enter the portion 82 of the operating cam 51 in this position.

The indicating element 58 signalizes this switch position by one of the two colours.

When the switch is to be shifted to its other position, the user presses again the indicating element 58 so that the key element 53 is once more moved downwards, against the action of the spring 41. This causes the pins 48 positioned at the lower end of the upper portion 83 of the operating cam 51 to slide into the upper end position. Each of the cam followers 61 slides along a steep flank of the saw teeth 72, is released by the latter and comes to rest against the inclined flank of the saw teeth 15 in the medium case portion 2. It has been described before that the teeth in the upper case portion 10 are offset against the teeth in the medium case portion 2 by about half a tooth pitch (15 ). Accordingly, the cam followers 61 come to rest against the flanks of the teeth 15 at about their centers.

If thereafter the user does not continue to exert pressure on the indicating element 58, the key element 53 is urged upwardly by the spring 41, the cam followers 61 striking initially - because of the offset arrangement of the teeth - the inclined flanks 74 of the teeth in the upper case portion 2, at about their centers, and sliding thereafter into the groove 73 and there right to the end of the groove. During this upward movement of the key element 53, the pins 48 slide through the upper portion 83 and the inclined middle portion 82 into the lower portion 81 of the operating cam 51, and the actuating element 42 rotates about the angle defined in the manner described above (about 30 ) and presses upon the two other diametrically opposite contact bridges 31, thus interconnecting the contact pins 22 and 23.Any return movement of the actuating element from this position is prevented due to the fact that to allow this movement the key element 53 would have to be pressed down against the action of the spring 41, and this can be achieved only by pressure exerted on the indicating element 58.

In another embodiment of the invention in which the switch is used as a mere key switch, the cam followers 61 are missing. In the inoperative position of the switch, the key element 53 is retained by the spring 41 in its upper end position, and the pins 48 occupy their position at the lower end of the lower paraxial portion 81 of the operating cam 51. Due to the fact that the key element 53 is retained against rotation by the extended contact pins 25, the actuat ing element 42 bears with the force required in view of the resilient force of the elastically deformed contact bridges 31 against two diametrically oppo site annular spring ends whereby in the embodiment shown in Figure 2 the contacts 22 and 24 are connected.Now, when pressure is applied on the indicating element 58, the key element 53 moves downwardly so that the pins 48 guided in the operating cam 41 move upwardly. As a result thereof, the operating element 40 and the actuating element 42 perform a rotary movement during the period of time in which the pins 48 slide upwardly along the middle inclined cam portion 82. Now, the contacts 22 and 23 are connected by the other spring-like contact bridges 31 of the contact element 30, and this again independent of the pressure being exerted upon the indicating element 58. Here again7 the contact pressure is exclusively determined by the size of the rotary movement performed by the actuating element 42, which depends on the shape of the operating cam 42, and the resilient force of the contact bridges 31 deflected by the actuating element 42.When the pressure exerted upon the indicating element 58 is released, the key element 43 is again urged upwards by the spring 41, and the cam followers 48 move downwardly along the cam 41. As a result thereof, the actuating element 42 turns in clockwise direction back into the position shown in Figure 2, so that the contact elements 30 break the contact between the contact pins 22 and 23 and remake the contact between the contact pins 23 and 24. If no cam followers 61 are present, i.e. if the switch of the invention is used as a mere key switch, the arrangement can do without the upper paraxial portion 83 of the operating cam 51, and without the teeth 15,72,73,74.

Finally, the contact pins 22 to 24 coacting with a contact element 30 are equally spaced along a straight line, and the contact pins 22 to 25 form the corners of squares the side length of which corresponds to the grid spacing of a grid plate with a module of 2.54 or 5.08 mm.

Instead of two contact elements 30, it is also possible to provide only one contact element. Further, the three contact pins 22 to 24 may be exchanged against only two switch pins 22 and 23, or 23 and 24, if a single-throw switch or key is to be realized instead of the double-throw switch shown in the drawing.

The switch of the invention is particularly suited for use in assembly panels using a modular system, in which case the contact pins are connected by special conductor boards, or wired. The switch may also be provided with an additional contact pin in its axis of symmetry which may be conductively connected to the indicating element as a third connection.

If necessary, the indicating element may be covered by a transparent cap or enclosed in a small tube section. Also, the indicating element 58 may be replaced by a solid pin or the like connected rigidly with the key element.

To facilitate the assembly of this switch or key, the bottom may be split up in the area of the opening 21 into two or more pieces.

In other embodiments of the invention, the solid cylinder 43 of the key element 53 is of two-piece design and provided in the sectional plane with two surfaces extending at a right angle relative to the axis of symmetry 20 and serving as support for a spiral spring or the like. This offers the advantage that in each of the switch positions of the detent switch of the invention, the annular face 55 comes to rest against the lower face of the case portion 2 when the operating pressure exerted on the indicating element 58 is released and that the indicating element 58 provides a substantially flush seal for the switch at the case cover 2 so that the switch is largely protected from external adverse influences, such as dust or humidity.

In other embodiments of the invention, the connection element 32 is provided with only one contact bridge which is alternately brought into contact with the contact 22 or 24 by a corresponding pivotal movement about the axis 23.

In the described embodiment of the invention, the operating cam takes the form of a recess in the key element, and the cam follower takes the form of a projection on the actuating element 42. In other embodiments of the invention, the operation of the key may be transformed into a pivotal movement by the cooperation of other parts of the switch. For instance, the operating cam may be formed by a groove milled into the inner surface of the case portion 10, and a projection provided on a part rotatably seated on the key element, for instance a projection provided on a ring, may be guided in the said operating cam, in which case the pivotal movement of the part mounted to pivot relative to the key element, but fixed on the latter against rotation, is transferred to the actuating element, for instance by paraxial guides provided in the actuating element and pins or the like which are rigidly connected to the said rotatable part and engage the said guides to slide therein in longitudinal direction.

Claims

1. A switch, in particular for installation in assembly panels, comprising a key element moveable within a switch case against the action of a spring, for manual operation of the switch, and a contact system with fixed and moveable contact elements, wherein the key element comprises an indicating element.

2. A switch in accordance with claim 1, wherein the indicating element is formed by a diode operable in two emission colours.

3. A switch in accordance with claim 2, wherein the diode indicate the respective positions of the switch.

4. Aswitch in accordance with claim 1,wherein the indicating element arranged on the operator's end of the key element is covered by a transparent cap.

5. A switch in accordance with claim 1, wherein the indicating element arranged on the operator's end of the key element is enclosed by a short tube section.

6. A switch in accordance with claim 1 comprising a spring acting upon the key element, wherein the indicating element has a diameter smaller than that of the neighbouring section of the key element so that the key element exhibits at the operator's end an annular end face surrounding the indicating element, which annular end face is urged by a spring against the inner surface of the switch case.

7. A switch in accordance with claim 1, wherein a contact pin fixed in the base of the switch is provided for at least one connection of the indicating element.

8. A switch in accordance with claim 7, wherein certain contact pins provided for connecting the indicating element are extended to project beyond the contact pins leading to switch contacts and these extensions of the contact pins are connected with electric lines leading to connections of the indicating element.

9. A switch in accordance with claim 8, wherein the key element comprising the indicating element is provided with bores engaged by extensions of contact pins and a spiral spring made of an electrically conductive material is arranged at the upper end of the contact pin and has its end facing away from the contact pin in contact with connection lines for the indicating element.

10. A switch in accordance with claim 1,wherein electric lines leading to connection of the indicating element form guides for the longitudinal movement of the key element.

11. A switch substantially as herein described with reference to and as illustrated in the accompanying drawings.