GB2089129A

GB2089129A - A push-button switch

Info

Publication number: GB2089129A
Application number: GB8130713A
Authority: GB
Original assignee: Schoeller and Co Elektrotecnische Fabrik GmbH and Co
Current assignee: Schoeller and Co Elektrotecnische Fabrik GmbH and Co
Priority date: 1980-10-18
Filing date: 1981-10-12
Publication date: 1982-06-16
Also published as: FR2492582A1; ES8207382A1; DE3039419C2; ES506306A0; GB2089129B; SE442795B; FR2492582B1; DE3039419A1; SE8105839L; IT1144838B; IT8168331A0

Abstract

A push button switch comprises a pushbutton 3 for actuating a snap acting contact 16 via an actuating spring 28 which is integral with restoring springs for the pushbutton 3. The restoring springs are supported on members 55,56 attached to a base plate 2 carrying the contacts 16 17, the members 55,56 being snapped into recesses 57,58 in the pushbutton 3 for returning the pushbutton 3 on the base plate 2. In an illuminated push-push switch, the spring 28 is carried by the pushbutton 3 and operates a rotatable cam 27 via a star wheel to cause actuation of the contacts 16,17. Most of the switch components are held together by snap connections. The spring 28 may alternatively act directly on the movable contact 16 to define a retractive switch. <IMAGE>

Description

SPECIFICATION A push-button switch The invention reiates to an electrical push-button switch, especially for motor vehicles.

The switches which are installed at present by the motor vehicle manufacturing industry have to be designed for direct current 15 A, 12 V, and consequently high contact pressures, large-volume contacts and high actuating forces of more than 10 N are required. In addition, these switches also require large installation depths because of levers, notches or other features. A stroke of severai millimeters is required so that the operational position of the switch can be seen by the position of the switch button ortheswitch knob. By means of a colour change in the illumination incorporated in the switch, the "on" position is also indicated during night travel. Because of the need to identify the operational positions during day and night travel, these switches require considerable space in front.

The object of the invention is to provide a push-button switch which requires little actuating force, a small switching stroke, a small installation depth and little space in front. In addition, illumination of the switch button should facilitate finding same in the dark, and the function of the switch should be indicated.

According to the present invention there is provided an electrical push-button switch, more especially for motor vehicles, comprising a rotatable element actuated by a push-button and which acts upon a monostable snap switch.

The advantage of the switch according to the Invention is that, because of the high-speed switching of the snap switch, only a small switching stroke with a small actuating force is necessary for actuating the push-button, so that the arrangement is similar to a sensor key.

In addition, the flat-fronted switch may be arranged in accordance with styling requirements without making it more difficult to meet safety requirements.

Because of the monostable snap switch in conjunction with the rotatable element, "on" and "off" switching may only be effected in one direction by pressing a button. Thus, no reciprocal movement are required for the "on" and "off" switching processes, i.e. the snap switch does not have to be actuated once upards and then, reciprocally, downwards.

Because of the high-speed switching of the snap switch, relatively high direct currents of 15 A, and briefly even higher currents, may be switched with actuating forces of 1 to 3 N.

One preferred embodiment of the invention has a rotatable element designed as a cam member whose cams act upon the contact spring of the snap switch.

The snap switch and cam member may be disposed on a base plate which carries the push-button, which base plate, together with the attached push-button, may be inserted into a frame-like housing. The cam member may be mounted rotatably in two bearing blocks mounted on the base plate. The cam member may preferably have a hexagonal cross-section, and three of its side faces may be spaced further from the axis of rotation than the other three side faces located therebetween, in order to alternately determine the "on" and "off" positions of the snap switch contacts. A star wheel, preferably having six teeth, may be provided on the cam member for engagement with a tappet spring which is actuated by the push-button and ensures that the cam member rotates when the push-button is actuated; the tappet spring may form a structural unit with the restoring springs for the push-button.Tappet and restoring springs may also be disposed one above the other and be mounted jointly on the push-button. The two restoring springs of the tappet spring may be supported on hooks, attached to the base plate, in order to retain the push-button.

The tappet spring may be mounted on the pushbutton. A displaceable intermediate member, which is guided in the base plate, may be provided between the cam member and the leaf spring of the snap switch, which leaf spring carries the movable contact, in order to define the point of application of the actuating force. The angular intermediate member may be positively guided, by means of one arm guided in a slot in the base plate and may have a wedge-shaped projection, more especially a rib or an embossed portion, on its other arm, for abutment with the leaf spring of the snap switch. An illuminating device, mounted on the base plate, may protrude into the push-button.The illuminating device may comprise two differently coloured lamps, one of which serves as a light to facilitate location of the switch in the dark and the other of which serves as a function indicator. in this case, the locating light may be switched off when the function indicator lights up upon actuation of the push-button switch, or the lamp of the locating light may continue to shine, but will be outshone by the function indicator lamp. The lights of the illuminating device may be attached to retaining and lead-in plates or wires, mounted on the base plate, and may be disposed beneath a translucent symbol plate of the push-button. The cam member may comprise further cams which act upon a switch contact in order to switch the locating light on and off.In addition, the cam member may comprise a plurality of switching zones for the simultaneous actuation of a plurality of snap switches, disposed one alongside the other on the base plate with the associated intermediate members or other switches.

The push-button may be guided in the base plate of the switch. The guidance for the push-button may comprise pins of any desirable cross-section which are mounted on the push-button and are guided in column supports attached to the base plate. However, a dovetail guidance means may also be used for guiding the push-button. All the essential members and components of the switch may be held together by means of snap connections, and the snap connection between the base plate and the push-button may be designed so that it also serves to limit the stroke. This is made possible by the hooks of the snap connection which protrude into slots in the push-button.

As a further alternative embodiment of the inven tion, the switch may also be designed as a pulse switch. In this case, the tappet spring has an extended arm which acts directly upon the leaf spring of the snap spring so that there is no need for any cam member nor any intermediate member.

The present invention will be described further, by way of example, with reference to the accompanying drawings, in which : Figure 1 is a longitudinal section through a push-button switch, taken along the line I - I in Figure 4; Figure 2 is a section through a push-button switch taken along the line II - II in Figure 4; Figure 3 is a section through a push-button switch taken along the line Ill - lil in Figure 4; Figure 4 is a plan view of the base plate of a push-button switch without the illuminating device; Figure is a plan view of the two lamps of the illuminating device and the push-button frame; Figure 6 is a section through the notches of individual components of the push-button;; Figure 7 is a section through the base plate and the contact stop of the push-button taken along the line VIl-VIl in Figure 4; Figure 8 is a section taken along the line VIII - VIII in Figure 7; Figure 9 is a perspective view of a cam member of the push-button; Figure 10 is a perspective view of a tappet spring mounted on the push-button; Figure 11 is a perspective view of an angular intermediate member which acts upon the leaf spring of the snap switch; Figure 12 shows one circuit example for the illuminating device; Figure 13 is a plan view of the base plate of a further embodiment of the invention having two snap switches disposed one alongside the other; Figure 14 is a section taken along the line XIV - XIV in Figure 13;; Figure 15 is a section through the base plate of a further embodiment of the invention having a snap switch designed as a change-over switch, taken along the line XV - XV in Figure 16; Figure 16 is a plan view of the embodiment shown in Figure 15; Figure 17 is a perspective view of a cam member for two on/off switches which are disposed one alongside the other and which form one 2-stage switch; and Figure 18 is a longitudinal section through a switch, designed as a key, in accordance with Figure 1.

According to Figures 1 to 8, the switch of the invention comprises a frame-like housing 1, a base plate 2 and a push-button 3. A snap switch 4 is mounted on the base plate 2. A leaf spring 6 of the snap switch 4 is connected to a contact plate 10 by means of the rivet 5. The leaf spring 6 comprises a snap spring 7 which is mounted, with a cutting edge 8, in a groove 9 in the contact plate 10 secured on the base plate. On the free end of the leaf spring 6 there is a movable contact 16 which co-operates with a fixed contact 17 and which abuts the stop 18 in its rest position. The fixed contact 17 is designed as a rivet, by means of which a contact plate 19 is mounted on the base plate 2.Located above the leaf spring 6 of the snap switch 4 is a cam member 27 which is mounted rotatably in two bearing blocks 25 and 26, provided on the base plate 2, and upon which cam member 27, a tappet spring 28 acts, the spring 28 being mounted on the push-button 3. In addition, a plurality of electricaliy conductive retain ing plates 31,32 and 33 are mounted on the base plate 2 and carry lamps 34 and 35 of an illuminaing device 36, as shown in Figure 5. The illuminating device 36 is disposed beneath a translucent symbol plate 37 of the push-button 3, which is omitted in Figure 5. The retaining plate 31 is connected to the contact plate 10,the retaining plate 33 is connected to a contact plate 38, and the retaining plate 32 is connected, by means of a switching contact 39, to a contact plate 40.

The section shown in Figure 2 shows the switching contact 39 which is disposed beside the snap switch 4 and serves to switch a green lamp 34 of the illuminating device 36, on and off, for example, as can be seen from the wiring diagram shown in Figure 12. The switching contact 39 is a rest contact and is actuated in the same manner as the snap switch 4, by the cam member 27.

Figure 3 shows the two bearing blocks 25 and 26 which are provided, on their free ends, with inclined faces for snapping in axle pins 45 and 46 of the cam member 27. Disposed between the leaf spring 6 and the cam member 27 there is an angular intermediate member 50 which is displaceably guided, by one arm, in a slot 51 in the base plate 2 and has, on its other arm, an embossed projecting portion 52 which rests on the leaf spring 6 of the snap switch 4 in orderto define accurately the pointofapplication of the actuating force. The tappet spring 28, mounted on the push-button 3, has two resilient arms 53 and 54 which are supported on the hooks 55 and 56 (Figure 6), mounted on the base plate 2, for the push-button 3.The hooks 55 and 56 snap into recesses 57 and 58 in the push-button 3 and also serve simultaneously as stops for defining the stroke of the push-button 3.

Figure 4 shows a plan view of the base plate 2, wherein, for reasons of ciarity, the housing 1, the push-button 3 and the illustrating device 36 are omitted. The reference numerals 60,61,62 and 63 denote tubular members which are mounted on the base plate 2 and into which pins 20,21, 22, 23 protrude, these pins being mounted on the pushbutton 3, so that a form of column guidance is provided for the push-button 3 and this guidance prevents the button from tilting or jamming. Instead of the circular cross-section which is shown as an example, any other suitable cross-section may also be used for the pins and tubular members.

The illuminating device 36, which was omitted from Figure 4, is shown in Figure 5 together with the frame-like push-button 3. However, the symbol plate 37, which is clampable onto the push-button 3, is omitted here, this symbol plate 37 serving to cover and protect the illuminating device 36 and carrying a transparent symbol for identifying the switch.

Figure 6 shows the notch arrangement intercon necting the individual components, namely the symbol plate 37 and the push-button 3, the pushbutton 3 and the base plate 2, and the base plate 2 and the housing 1. No screw couplings are therefore required for these members, so that a time-saving assembly of the individual parts is possible. Figures 7 and 8 show the notching of the stop 18 with a retaining device mounted on the base plate 2. The retaining device comprises two clamps 66 and 67, into which the bar-like stop 18 is clamped.

The perspective view of the cam member 27 in Figure 9 shows that this member comprises three different sections. The first section 70 is of a triangular design and serves to actuate the switch contact 39; the second section 71 forms, with its 6 teeth, a star wheel and is designed to engage in the tappet spring 28 so as to rotate the cam member 27; and the third section 72 has a hexagonal crosssection and actuates the snap switch 4. The narrow side faces 73 of section 72 are further spaced from the axis of rotation than the three side faces 74, located inbetween and determines alternately the "on" and "off" positions of the snap switch 4.

Figure 10 shows the tappet spring 28 and the restoring spring, which comprises the resilient arms 53 and 54, for the push-button 3, which form one structural unit. The rectangular aperture 75 serves to secure the spring on the push-button 3.

The angular intermediate member shown in Figure 11 has two arms 80 and 81, of which the arm 80 is guided in a slot 51 in the base plate, whilst the other arm 81 is provided with the embossed projecting portion 52 for engaging the leaf spring 6 of the snap switch 4.

The base plate 2 shown in Figures 13 and 14 is provided with two adjacent snap switches 85 and 86 and the two associated intermediate members 87 and 88. As a further embodiment, Figures 15 and 16 show a snap switch designed as a change-over switch. In this case, the stop 18 is replaced by a further fixed contact 90 which co-operates with the movable contact 16. If two adjacent on/off switches are designed as a 2-stage switch, then the cam member 91 has the form shown in Figure 17.

The mode of operation of the above-described switch is as follows: When the button 3 is pressed, the tappet spring 28 rotates the star wheel 71 in a radial movement and therewith rotates the cam member 27 through one step, e.g. about an angle of rotation of 60 . The intermediate member 50, with the embossed portion 52, presses downwards onto the leaf spring 6 of the snap switch 4 for the circuit which is opened at the commencement of operation. After the pressure point is reached, the leaf spring 6 of the snap switch 4 snaps over, and the contact 16 closes the circuit by means of the fixed contact 17. The leaf spring 6 remains in this state because the narrow face 73 of the cam member 27, which is spaced further from the axis of rotation of the cam member 27, now determines this position of the leaf spring 6.After the button 3 has been released, the button is moved into the initial position by means of the arms 53 and 54 of the tappet spring 28. During this return stroke, the tappet spring 28 returns to its initial position relative to the star wheel 71. Upon a subsequent pressing of the button 3, the same course of movement is effected with the star wheel 71 and the cam member 27, and the narrow face 73 of the cam member 27 hereby rotates about a further 60 , whereby the wide face 74, which is closer to the axis of rotation of the cam member 27, abuts the intermediate member 50. Because of the resilience of the leaf spring 6, the intermediate member 50 is biased towards the cam member 27 and when the snap-back pressure point of the leaf spring 6 is reached, the leaf spring snaps over and opens the contacts 16 and 17.Thus, the switching position is determined by the cam member 27. After the button 3 is reieased, the button is moved back again into the initial position, and the tappet spring 28 returns to the initial position once more. When the button 3 is pressed again, the first-described course of movement is effected with the closure of the contacts 16 and 17. When the button is pressed again, the contacts 16 and 17 are opened again, and soon.

In addition to the on/off switch as described, the snap switch 4 may also be designed as a single-pole change-over switch. Multiple on/off swiches and multipolar change-over switches may be provided using a multiple cam member. The embodiment according to the invention is in no way limited to a hexahedral cam member and a star wheel with 6 teeth. Other embodiments may be realized using this principle. This also applies to the cam member which may be designed so as to be staggered reciprocally in respect of its geometr, i.e. the synchronously acting sections may simultaneously close one snap switch and open a second snap switch.

According to the circuit in Figure 12, the red light 35 for indicating the function lights up in the "on" position. When the instrument lights of the motor vehicle are switched on by the main switch, the indicator light 34, for example, a green light, is switched on. The green light 34 is extinguished by the second switching contact 39, which is likewise actuated by the cam member 27, when the snap switch 4 is closed by pressing the button 3 and a load, e.g. an electric motor 41, is switched on. The switching contact 39 for the green light 34 may be of an extremely simple design, without high-speed switching, because only a light-current of a few mA is switched. However, the change-over is effected synchronously because the adjacent switches 4 and 39 are actuated by a common cam member 27.The switching contact 39 may even be eliminated with the green light 34 shining permanently but being outshone by the stronger red light when the switch is switched on.

The lights are mounted on supports 31,32,33 which produce simultaneously the electrical connection between the base plate and the switches. These supports protrude through the base of the pushbutton housing. The two lights 34 and 35 are fixedly disposed in the push-button housing. The button housing is sealed by a transparent cover plate 37, which may be designed as a symbol plate. When the push-button 3 is actuated, the lights are not moved and their positions remain unchanged.

If the switch is not to be used as an on/off switch, but as a pulse switch, then the embodiment shown in Figure 18 is applicable. The tappet spring 28 of the switch shown there has an extended arm 29 which acts directly upon the leaf spring 6 of the snap switch 4. The cam member 27 and the intermediate member 50 are therefore eliminated, since contact is only to be made for the duration of time when the button of the switch is pressed.

The invention has been explained fully above with reference to several embodiments shown in the drawing. However, it is obvious that the invention is in no way limited to these examples, because there are numerous possible modifications in respect of design and arrangementforthe individual components of the switch without the scope covered by the invention being exceeded thereby.

Claims

1. An electrical push-button switch, more especially for motor vehicles, comprising a rotatable element actuated by a push-button and which acts upon a monostable snap switch.

2. A push-button switch according to claim 1, in which the rotatable element is designed as a cam member whose cams act upon a contact spring of the snap switch.

3. A push-button switch according to claim 2, in which the snap-switch and the cam member are disposed on a base plate which supports the pushbutton.

4. A push-button switch according to claim 3, in which the base plate, with the attached push-button, is insertable into a frame-like housing.

5. A push-button switch according to claims 3 or 4, in which the cam member is mounted rotatably in two bearing blocks mounted on the base plate.

6. A push-button switch according to claims 2 to 5, in which the cam member has a hexahedral cross-section, and three of its side faces are spaced further from the axis of rotation of the cam member than the three side faces which lie inbetween, so as to fix alternately the "on" and "off" positions of the snap switch contacts.

7. A push-button switch according to claims 2 to 6, in which a star wheel is provided on the cam member and has teeth for engagement with a tappet spring actuated by the push-button.

8. A push-button switch according to claim 7, in which the tappert spring forms a structural unit with restoring springs for the push-button, or in which tappet and restoring springs are disposed one above the other and are mounted jointly on the pushbutton.

9. A push-button switch according to claim 8, in which the two restoring springs of the tappet spring are supported on the hooks attached to the base plate in order to retain the push-button.

10. A push-button switch according to claims 7 to 9, in which the tappet spring is secured to the push-button.

11. A push-button switch according to claims 2 to 10, in which a displaceable intermediate member is guided in the base plate and is provided between the cam member and the contact spring of the snap switch, which contact spring carries the movable contact so as to define the point of application of the actuating force.

12. A push-button switch according to claim 11, in which the angular intermediate member is positively guided, by one arm, in a slot in the base plate and has, on its other arm, a projection, more especially a rib or an embossed portion, for abutment against the contact spring of the snap switch.

13. A push-button switch according to claims 1 to 12, in which an illuminating device is attached to the base plate and protrudes into the push-button.

14. A push-button switch according to claim 13, in which the illuminating device.comprises two differently coloured lamps, one of which serves as a light to facilitate location in the dark and the other serves as a function indicator.

15. A push-button switch according to claim 14, in which the lamps of the illuminating device are attached to retaining and lead-in lates or wires, mounted on the base plate, and are disposed beneath a translucent symbol plate of the pushbutton.

16. A push-button switch according to claims 13 to 15, in which the cam member comprises further cams which act upon a switch contact in order to switch the location light on and off.

17. An electrical push-button switch substantially as herein described with reference to and as illustrated in the accompanying drawings.

17. A push-button switch according to claims 2 to 15, in which the cam member comprises a plurality of switching zones for the simultaneous actuation of a plurality of snap switches, disposed one alongside the other on the base plate with the associated intermediate members or other switches.

18. A push-button switch according to claims 1 to 17, in which the push-button is guided in the base plate of the switch.

19. A push-button switch according to claims 1 to 18, in which guidance means for the push-button comprises pins of any desirable cross-section which are mounted on the push-button and are guided in column supports attached to the base plate.

20. A push-button switch according to claims 1 to 19, in which a dovetail guidance means is used for guiding the push-button.

21. A push-button switch according to claims 1 to 20, in which all the essential members and components of the switch are held together by means of snap connections.

22. A push-button switch according to claim 21, in which the snap connection between the base plate and the push-button is designed so that it also serves simultaneously to limit the stroke of the push-button.

23. A push-button switch according to one of claims 1 to 22, in which a tappet spring is provided which has an extended arm which acts directly upon the contact spring of the snap switch.

24. An electrical push-button switch substantially as herein described with reference to and as illustrated in the accompanying drawings.

New claims or amendments to claims filed on 3rd February 1982 Superseded claims All New or amended claims:

1. An electrical push-button switch, more especially for motor vehicles, comprising a cam member which acts upon a monostable snap switch and on which a star wheel is mounted, a tappet spring engaging in the teeth of the star wheel and being actuated by the push-button, and the cam member and the snap switch being disposed on a base plate carrying the push-button, wherein the tappet spring forms a structural unit with restoring springs for the push-button, and the restoring springs are supported on hooks attached to the base plate in order to retain the push-button.

2. A push-button switch according to claim 1, in which tappet and restoring springs are disposed one above the other and are mounted jointly on the push-button.

3. A push-button switch according to claim 1 or 2, in which a displaceable intermediate member is guided in the base plate and is provided between the cam member and the leaf spring of the snap switch, which leaf spring carries the movable contact so as to define the point of application of the actuating force.

4. A push-button switch according to claims 1 to 3, in which the angular intermediate member is positively guided, by its one arm, in a slot in the base plate and has, in its other arm, a wedge-shaped projection, especially a rib or an embossed portion, for abutment against the leaf spring of the snap switch.

5. A push-button switch according to claims 1 to 4, in which an illuminating device is attached to the base plate and protrudes into the push-button.

6. A push-button switch according to claims 1 to 5, in which the illuminating device comprises two differently coloured lamps, one of which serves as a light to facilitate location in the dark and the other serves as a function indicator.

7. A push-button switch according to claims 1 to 6, in which the lamps of the illuminating device are attached to retaining and lead-in plates or wires mounted on the base plate, and are disposed beneath a translucent symbol plate of the pushbutton.

8. A push-button switch according to claims 1 to 7, in which the cam member comprises further cams which act upon a switch contact in order to switch the location light on and off.

9. A push-button switch according to claims 1 to 8, in which the cam member comprises a plurality of switching zones for the simultaneous actuation of a plurality of snap switches disposed one alongside the other on the base plate, with the associated intermediate members or other switches.

10. A push-button switch according to claims 1 to 9, in which the push-button is guided in the base plate of the switch.

11. A push-button switch according to claims 1 to 10, in which the guidance means forthe pushbutton comprises pins of any suitable cross-section which are guided in columns attached to the base plate and are mounted on the push-button.

12. A push-button switch according to claims 1 to 11, in which a dovetail guidance means is used for guiding the push-button.

13. A push-button switch according to claims 1 to 12, in which all the essential members and components of the switch are held together by means of snap connections.

14. A push-button switch according to claim 13, in which the snap connection between the base plate and the bush-button is designed so that it also serves simultaneously to limit the stroke.

15. An electrical push-button switch, more especially for motor vehicles, comprising a tappet spring which acts directly upon a monostable snap switch, said tappet spring being actuated by the pushbutton, and the snap switch being disposed on the base plate carrying the push-button, wherein the tappet spring forms a structural unit with restoring springs for the push-button, and the restoring springs are supported on hooks attached to the base plate in order to retain the push-button.

16. A push-button switch according to claim 15, in which the tappet spring has an extended arm which acts directly upon the leaf spring of the snap switch.