EP0031038B1 - Step by step switch mechanism - Google Patents

Description

The invention relates to a forward and reverse switchable stepping mechanism for a multi-stage switch, which switching mechanism is arranged in a housing and has an integrally formed drive provided with two pushbuttons, two switching elements, two plungers and a latching element, on which a return spring acts and which acts in a linear manner Working movement with one or the other switching element can be brought into engagement with a pinion of a character carrier arranged on the axis of symmetry of the housing and operatively connected to the latching element.

From DE-C-22 62 274 a step switch is known, the button is integrally formed with the push buttons. The push buttons are each connected to the push button via a resilient web, the push button being arranged in the housing to be longitudinally displaceable and slightly tiltable in two directions. When a button is pressed, half a switching step is achieved by the engagement of a transport pin on the number wheel, which is completed by the restoring force of a spring when the button slides back through a transport wedge. In this step-by-step mechanism, the rotary movement of the number wheel takes place jerkily in two phases and essentially counter to the respectively actuated button.

From DE-A-26 53 172 a step-by-step mechanism for a key coding switch is known, in which a button is provided for the forward and reverse switching step. The individual button is provided with approximately C-shaped actuating and locking cams, which essentially grip over the ring gear of a character carrier. When a button is pressed, the associated actuating cam sets the ring gear in motion, while the locking cam of the other button is deflected from its rest position by the ring gear. For production as well as for assembly, it is disadvantageous that the drive consists of two separate parts and that two individual springs must also be installed.

Furthermore, EP-A. 0 006 967 discloses a stepping mechanism for a multi-stage switch, which has two functionally separate actuating elements provided with plungers, molded switching elements and spring elements. In this switching mechanism, the individual switching element for the switching process is inevitably deflectable from a rest position, can be brought into engagement with the pinion of a character carrier and, after the switching step has been completed, can be returned to the rest position by the restoring force of the spring elements.

The invention has for its object to provide a step-by-step mechanism in which, by pressing once, an exact, completed switching step is achieved in the direction of the respective push button, without the need for highly accurate dimensional tolerances of the individual parts or an adjustment. In addition, the drive should be in one piece, ensure simple assembly without additional aids and be able to be produced from plastic in the known injection molding process. These requirements should also be achievable when it comes to a miniature stepping switch.

• a) an dem einen Ende des Antriebs die für den Schaltvorgang mit dem Zahnritzel in Eingriff bringbaren und mit einem Steg biegeelastisch auslenkbar an den Stösseln angeformten Schaltelemente angeordnet sind,
• b) im Abstand zu den Schaltelementen das die gegenüberliegenden Stössel brückenartig miteinander verbindende Rastelement angeordnet ist,
• c) an dem Rastelement bezüglich der Gehäuse-Symmetrieachse symmetrisch angeordnete und in der Ruhestellung mit dem Zahnritzel im Eingriff stehende Rastnocken angeformt sind, und
• d) für den Schaltvorgang das Rastelement mit den Rastarmen derart biegeelastisch und das Zahnritzel freigebend an den Stösseln angeformt ist, dass beim Schaltvorgang der dem jeweils betätigten Stössel gegenüberliegende Stössel in Ruhestellung verbleibt.

According to the invention, this object is achieved in that

• a) at one end of the drive the switching elements which can be brought into engagement with the pinion for the switching process and which can be deflected in a flexurally elastic manner with a web are arranged on the tappets,
• b) the latching element, which connects the opposing plungers in a bridge-like manner, is arranged at a distance from the switching elements,
• c) molded on the locking element with respect to the housing axis of symmetry symmetrically and in the rest position with the pinion engaging locking cams are formed, and
• d) for the switching process, the latching element with the latching arms is formed so flexibly and releasing the pinion on the tappets that the tappet opposite the respective tappet remains in the rest position during the switching process.

Further features of the invention will become apparent from the following description in conjunction with the drawing and the claims.

• Figur 1 eine im grösseren Massstab und im Schnitt dargestellte Draufsicht eines Schrittschaltwerks mit in einem Gehäuse angeordnetem Antrieb,
• Figur 2 eine isometrisch und bezüglich der Symmetrieebene 11 im Schnitt dargestellte Hälfte einer ersten Variante des Antriebs gemäss Fig. 1,
• Figur 3 eine gemäss der Linie III-III in Figur 1 dargestellte Schnittansicht des in dem Gehäuse angeordneten Schrittschaltwerks in teilweise zerlegtem Zustand,
• Figur 4 eine isometrische Darstellung eines 'Antriebs des Schrittschaltwerks gemäss einer zweiten Variante,
• Figur 5 eine im Schnitt dargestellte Draufsicht des Schrittschaltwerks mit der zweiten Variante. des Antriebs gemäss Fig. 4,
• Figur 6 eine im Schnitt dargestellte Draufsicht des Schrittschaltwerks mit einer dritten Variante eines Antriebs, und
• Figur 7 eine isometrisch und bezüglich der Symmetrieebene VII im Schnitt dargestellte Hälfte der dritten Variante des Antriebs gemäss Fig. 6.

The invention is described below in connection with the drawing. It shows:

• FIG. 1 shows a plan view, on a larger scale and in section, of a stepping switch mechanism with a drive arranged in a housing,
• FIG. 2 shows an isometric half of a first variant of the drive according to FIG. 1, shown in section with respect to the plane of symmetry 11,
• FIG. 3 shows a sectional view of the stepping mechanism arranged in the housing according to the line III-III in FIG. 1 in a partially disassembled state,
• FIG. 4 shows an isometric illustration of a drive of the stepping mechanism according to a second variant,
• Figure 5 is a sectional plan view of the step switch with the second variant. 4 according to FIG.
• Figure 6 is a sectional plan view of the stepping mechanism with a third variant of a drive, and
• FIG. 7 shows an isometric half of the third variant of the drive according to FIG. 6, shown in section with respect to the plane of symmetry VII.

1 shows a sectional top view of a pushbutton switch 100, and a housing 60 can be seen, which is formed from a side wall 50, an end face 41, an upper and a lower wall 59, 59 'and a rear wall 56. In the housing 60 is essentially a drive 30, a character carrier 79 with a tooth attached to it pinion 80 and a spring 70 existing forward and reverse switchable step switch arranged. The drive 30, which is designed to be mirror-symmetrical with respect to the axis of symmetry of the housing, comprises two pushbuttons 21, 21 '; two plungers 14, 14 '; two from elements 22, 22 '; 24, 24 'and 28, 28' switching elements 23, 23 'formed as well as a from the elements 37; 38, 38 '; 39, 39 'formed locking element 40. The drive 30 is associated with the plungers 14, 14' on pins 61, 61 'and on the inside 57, 57' of the wall 59, 59 'and with the switching elements 23, 23' Pins 54, 54 'and 53, 53' guided.

FIG. 2 shows isometric and half of the drive 30 with respect to the plane of symmetry or the section plane II and the pushbutton 21, the plunger 14, the switching element 23 and a section of the latching element 40 can be seen. The switching element 23 arranged at the front end is integrally formed on the plunger 14 with the web 22 and runs approximately parallel to the plunger 14 with the stepped switching arm 24. At the end of the switching arm 24, a switching cam 28 is formed which has a contact surface 27 and an inner surface 25. The contact surface 27 and the inner surface 25 enclose an acute angle.

In order to give the drive 30 additional rigidity, an angular corner piece 19 or 6 is formed on each end of the plunger 14. For the installation of the largest possible drawing medium 79, the corner pieces 19 and 6 are separated from one another by a recess 29. The corner piece 19 consists of an end wall 18 with an end face 20 and a side wall 15 arranged at right angles thereto. The push button 21 is arranged on the end face 20.

The side wall 15 is wedge-shaped and is delimited by an outer surface 16 which runs parallel to the plunger 14 and an inner surface 17 which is slightly inclined thereto. The corner piece is designed analogously and has an end wall 9 and an inner side 8 which runs parallel to the plunger 14 and on which a recess 7 is provided to hold the spring 70 (FIG. 1). The side wall 10 has an outer surface 11 and an inner surface 12, both of which run parallel to the plunger 14. A second inner surface 13 is slightly inclined to the outer surface 11 and gives the outer wall 10 a wedge-shaped end.

At a distance from the pushbutton 21, the V-shaped locking element 40, consisting of a locking arch 34 and the locking cam 37, is formed on the other end of the drive 30. The latching arch 34 essentially comprises the linear latching arm 38 and the latching arm 38 'which is integrally formed in mirror image, not shown here, and a middle piece 33 on which the latching cam 37 is integrally formed. The angle between the locking arm 38 or 38 'and the plunger 14 or 14' is approximately 45 °, the angle between the locking arm 38 and the mirror-image locking arm 38 'is approximately 90 °. The latching cam 37 has a convexly curved latching surface 35 and a concavely curved inner surface 36, which run essentially parallel to one another. Due to the narrow design of the locking arch 34 and the attachment point 39 to the plunger 14 and the attachment point 39 'to the plunger 14', not shown here, the locking element 40 is in relation to the push buttons 21, 21 'in the direction of the arrows 1 and 2 (FIG. 1). applied forces are designed to be flexible.

In Fig. 3 the switch is shown in a sectional view along the line 111-111 in Fig. 1 and you can see the housing 60, which is closed on one side by the side wall 50 and open on the other opposite side. Furthermore, one can see the pins 54, 53 and 61, the elements 21, 24, 28, 27 and 38 of the drive 30, the pinion 80 rotatable about an axle pin 52 and the spring 70 mounted on a cam 55 and locked in the recess 7.

The open side is closed by a circuit plate 44 shown at a distance from the open side for the sake of simplified illustration and by an end plate 43 also shown at a distance from the housing 60, for which purpose the housing 60 has at least one pin 46 at the corners, which snaps into a correspondingly assigned and provided in the end plate 43 bore 42. The corners of the side wall 50 are each provided with a bore 48, into each of which a pin 49 of an end plate 47 engages.

4, a drive 130 according to a second variant is shown isometrically and the switching element 23 can be seen with the pushbutton 21 and the web 22 and the switching element 23 'partially shown with the pushbutton 21' and the plungers 114, 114 '. This variant differs only in the embodiment of the locking element 140 from the drive 30 according to FIG. 2. The locking element 140 is V-shaped and comprises a central part 133 designed as a locking arch 134, which on its upper side 131 has a locking surface 135, 135 ' provided locking cams 137. Two latching arms 138, 138 'are formed on the latching arch 134 and in the central region 115, 115' of the plungers 114, 114 '. The latching surfaces 135, 135 'arranged on the latching cam 137 enclose an obtuse angle, while the latching arm 138 or 138' with the push button 21,. 21 'articulated half with respect to the plunger 114 or 114' encloses an angle of approximately 135 °. The reference numerals not shown in FIG. 4 for the individual elements are identical to the reference numerals of the corresponding elements according to FIG. 2.

5 shows in section a pushbutton switch 200 with the parts 70, 79, 80 arranged in the housing 60 and the drive 130 according to the second variant shown in FIG. 4. Here, the housing 60 corresponds to the parts 41; 46, 46 ';50;52; 53, 53 '; 54, 54 ';55;56; 59, 59 'and 61, 61' the housing described with reference to Figure 1 and the drive 130 with the essential elements 21, 21 '; 23, 23 '; 114, 114 'and 140 corresponds to the drive described with reference to FIG. 4.

The operation of the step switch in conjunction with the push button switch is described below.

As can be seen from FIGS. 1 and 5 described above, the switching mechanism which can be switched forwards and backwards and is used in the housing 60 optionally consists of the drive 30 according to FIG. 2 or the drive 130 according to FIG. 4, and the symbol carrier shown only schematically and in outline 79 with the pinion 80. The end face 41 of the housing 60 has a window 45 for dismantling the drawing medium 79 and two openings 51, 51 'for inserting and guiding the pushbuttons 21, 21' of the corresponding drive 30 or 130.

When the pushbutton 21 'according to FIG. 1 is actuated, for example, the plunger 14', which is guided on the inside 57 'of the wall 59' on the one hand and on the other hand through the pin 61 'which is fixedly connected to the side wall 50, moves in the direction of the arrow 1 in the direction of the arrow 1 During this movement sequence, the latching element 40 is simultaneously displaced in the arrow direction 1 into the position shown in dashed lines, while the other actuating element is not displaced. Associated with this is a deformation of the drive 30, which occurs essentially in the area of the attachment points 39, 39 '. By shifting the plunger 14 ', the locking cam 37 is inevitably shifted in the direction of the arrow 1, as a result of which it moves away from the pinion 80 and unlocks it. By further pressing the pushbutton 21 'in the direction of the arrow 1, the contact surface 27' of the switching cam 28 'engages with the pinion 80 and, when pressed further, causes the character carrier 79 to rotate by a full switching step of 36 °. During the actuation, a deflection of the switching element 23 'is prevented by the pins 54' and 53 'which are firmly connected to the side wall 50. The switching step in the direction of arrow 1 is ended and limited by contacting the corner piece 6 'with the associated pin 46'.

When the push button 21 'is released, the restoring force of the spring 70 moves the plunger 14' of the drive 30 in the direction of the arrow 2, the latching cam 37 first engaging in a tooth gap 78 of the toothed pinion 80 and, after a further movement in the same direction, the inner surface 25 'of the switching element 23 'is deflected towards the tappet 14' by the toothed pinion 80 now held by the locking cams 37, which is made possible by the web 22 'designed to be flexible. Due to the deflection of the switching element 23 ', the spring 70 can move the plunger 14' further in the direction of the arrow 2 until the switching cam 28 'has jumped over the pinion 80 and moves s.ch again into the rest position.

During each switching step, the pinion 80 is moved against the locking surface 35 of the in the Pfeilr rect ^t 1 moving the locking cam 37. The resulting pressure is experienced in the operation as a pressure point.

By repeatedly pressing one or the other pushbutton 21 or 21 ', the necessary switching steps are carried out until the character carrier 79 has reached the desired position, which can be easily read through the window 45.

When using the drive 130 of the second variant, the pinion 80 moves approximately in the same direction as the locking cam 137 with each switching step. Since the pinion 80 now exerts no pressure on the locking cam 137, no pressure point is felt when actuated.

The housing with the pegs, stops, etc. arranged in the interior of the housing on the side wall and the drive can preferably be produced from suitable plastic in an economical injection molding process, so that rational mass production and thus also low manufacturing costs are ensured.

In the following the invention is explained according to a third variant with reference to the drawing. 6 shows a sectional top view of a push-button switch 300 and a housing 260 can be seen, which is formed from a side wall 250, an end wall 241, an upper and a lower wall 259, 259 'and a rear wall 256. Arranged in the housing 260 is a stepping mechanism consisting essentially of a drive 230, a character carrier 279 with a toothed pinion 280 fastened thereon and a spring 270 mounted on a pin 255, which can be switched back and forth. The drive 230, which is designed to be mirror-symmetrical with respect to the axis of symmetry of the housing, essentially comprises two pushbuttons 221, 221 '; two plungers 214, 214 '; two of the essential elements 222, 222 '; 224, 224 'and 228, 228' switching elements 223, 223 'formed as well as a from the elements 235; 236, 236 '; 237, 237 '; 238 and 239, 239 'formed locking element 240.

In FIG. 7, one half of the drive 230 is shown isometrically and with respect to the axis of symmetry or the section plane VII, and the pushbutton 221, the plunger 214, the switching element 223 and a part of the locking element 240 can be seen. The switching element 223 arranged at the front end is formed laterally on the plunger 214 with the web 222 and runs approximately parallel to the plunger 214 with the stepped switching arm 224. At the end of the switching arm 224, a switching cam 228 is formed, which has a contact surface 227 and an inner surface 225. The contact surface 227 and the inner surface 225 form an acute angle.

In order to give the drive 230 additional rigidity, there is an angular corner piece 219 or 206 at both ends of the plunger 214 molded. For the installation of a drawing support 279 as large as possible, the corner pieces 219 and 206 are preferably separated from one another by a recess 229. The corner piece 219 consists of an end wall 218 with an end surface 220 and a side wall 215 arranged at right angles thereto. The push button 221 is arranged on the end surface 220. The side wall 215 is wedge-shaped and is delimited by an outer surface 216 running parallel to the tappet 214 and an inner surface 217 which is slightly inclined thereto. The corner piece 206 likewise has an inner side 208 running parallel to the plunger 214, on which a recess 207 for holding the spring 270 (FIG. 6) is visible. The side wall 210 has an outer surface 211 and an inner surface 212, both of which are inclined at approximately 30 ° to the plunger 214. A second outer surface 213 is slightly inclined to the outer surface 211 and gives the outer wall 210 a wedge-shaped closure.

At a distance from the push button 221, the locking element 240, which is only half visible and is U-shaped here, is formed approximately in the middle of the plunger 214. The half of the latching element 240, which is mirror-symmetrical with respect to the axis of symmetry of the housing or the section plane VII, consists of the likewise U-shaped latching arch 235, which is reinforced by the base plate 238, and the latching cam 237 formed on the latching arch 235, which is essentially perpendicular to the sectional plane VII has standing locking surface 234. The locking arm 236, which runs essentially parallel to the plunger, connects the detent element 240 to the plunger 214 in the region of the attachment point 239 (FIG. 6), the attachment point 239 being designed to be flexible in bending.

The reference numerals not shown in FIG. 7 for the individual elements of the drive 230 are identical to the elements and reference numerals according to FIG. 6, the reference numerals of the elements of the drive 230 arranged on the other side of the housing symmetry axis being provided with a line.

The operation of the step switch and the push button switch according to the third variant is described below.

As can be seen from the previously described FIGS. 6 and 7, the switchable forward and reverse switch mechanism inserted in the housing 260 consists of the drive 230 according to FIG. 7 and the schematically illustrated character carrier 279 with the pinion gear 280 rotatably arranged about the axis pin 252 (FIG. 6). The end wall 241 of the housing 260 has a window 245 for reading the character carrier 279 and two openings 251, 251 'for inserting and guiding the pushbuttons 221, 221' of the drive 230.

By actuating the push button 221, for example, the plunger 214 guided on the one side on the inside of the wall 259 and on the other side through the link 261 which is firmly connected to the side wall 250 moves in the direction of arrow 201 against the restoring force of the spring 270 The movement of the plunger 214 and the locking element 240 is displaced in the direction of arrow 201, while the other plunger 214 'undergoes essentially no displacement. Associated with this is a deformation which occurs essentially at the attachment points 239, 239 '. By moving the plunger 214, both locking cams 237, 237 'move essentially in the direction of arrow 201, as a result of which they are removed from the pinion 280 and the latter is unlocked. By further actuation of the pushbutton 221 in the direction of arrow 201, the contact surface 227 of the switching cam 228 engages with the pinion 280 and, upon continued actuation, causes the character carrier 279 to be rotated by an entire switching step of 36 °. During actuation, deflection of the switching element 223 is prevented by the pin 254, which is firmly connected to the side wall 250. The switching step in the direction of arrow 201 is ended by contacting the corner piece 206 with the rear wall 256 or the pin 246 of the housing 260.

When the push button 221 is released, the restoring force of the spring 270 moves the drive 230 in the direction of the arrow 202, the latching cam 237 ′ first engaging in an associated tooth gap 278 of the toothed pinion 280 and, after a further movement in the same direction, the second latching cam 237 engaging in the corresponding tooth gap . The toothed pinion 280 held by the locking cams 237 'deflects the switching element 223, which continues to move in the direction of the arrow 202, to the plunger 214, which is made possible by the web 222 which is designed to be flexible in terms of bending. Due to the deflection of the switching element 223, the spring 270 can move the drive 230 further in the direction of the arrow 202 until the switching cam 228 has jumped over the pinion 280 and moves back into the rest position. In the rest position, the two locking cams 237, 237 'press with their locking surfaces 234, 234' against the toothed pinion 280 by the restoring force of the spring 270, which is thereby fixed in position. By repeatedly pressing one or the other pushbutton, the necessary switching steps are carried out until the character carrier 279 has reached the desired position, which can be easily read through the window 245.

In this variant, too, the housing with the pins, stops, etc. arranged on the inside of the side wall and the drive can preferably be produced from suitable plastic in an economical spraying process, so that rational mass production and thus also low manufacturing costs are ensured.

To clarify the pressure point for each switching step, a flexible elastic attachment 262 or 262 'is formed on each plunger 214 or 214' of the drive 230 at a distance from the corresponding push buttons 221 or 221 '. At Each attachment 262, 262 'is formed with a wedge-shaped and spring-elastic cam 263 or 263' directed towards the inside of the wall 259 or 259 '. In each switching step, the cam 263 or 263 'assigned to the actuated plunger slides over a cam 264 or 264' formed on the inside of the wall 259 or 259 '. The consequent deflection of the attachment 262 or 262 'is perceived as a pressure point at the switch.

Claims (8)

1. Stepping switch mechanism, which can be switched forwards and backwards, for a multistage switch, which switch mechanism is arranged in a housing (60 ; 260) and comprises a one-piece drive (30 ; 130 ; 230) provided with two pushbuttons (21, 21' ; 221, 221'), two switch elements (23, 23' ; 223, 223'), two slides (14, 14' ; 214, 214') , and one locking element (40 ; 140 ; 240), which drive is subjected to the action of a return spring (70 ; 270) and which, in the event of linear operating movement with one or the other switch element, can be made to engage with a pinion (80 ; 280) of a symbol carrier (79 ; 279) in operative connection with the locking element and arranged on the symmetrical axis of the housing, characterised in that

a) the switch elements (23, 23' ; 223, 223'), which can be made to engage with the pinion (80 ; 280) for the switching operation and, with the use of a cross-piece (22, 22' ; 222, 222') are formed on the slides (14, 14' ; 214, 214') so as to be flexibly deflectable, are arranged on one end of the drive (30 ; 130 ; 230),

b) the locking element (40 ; 140 ; 240) connecting the opposite slides (14, 14' ; 114, 114' ; 214, 214') to each other in bridge-like fashion, is in space arrangement to the switch elements (23, 23' ; 223, 223'),

c) a locking cam (37 ; 137 ; 237, 237'), arranged symmetrically in respect of the axis of symmetry of the housing and engaged in the rest position with the pinion (80 ; 280), is formed on the locking element (40 ; 140 ; 240),
and

d) for the switching operation, the locking element (40 ; 140 ; 240) with the locking limbs (38, 38' ; 138, 138' ; 236, 236') is flexibly formed on the slides (14, 14' ; 114, 114' ; 214, 214') and can release the pinion (80 ; 280), in such a way that during the switching operation, the slide opposite the respectively actuated slide remains in the rest position.

2. Stepping switch mechanism according to claim 1, characterised in that the locking element (40) is V-shaped and is arranged at the other end of the drive (30) and has on its central part (33) facing the pinion (80) the locking cam (37), which is provided with a convex-curved locking surface (35).

3. Stepping switch mechanism according to claim 2, characterised in that the two locking limbs (38, 38') of the V-shaped locking element (40), formed on the slides (14, 14') with flexible connecting points (39, 39'), together form an angle of approximately 90° and, in relation to their associated slides (14, 14'), an angle of approximately 45°.

4. Stepping switch mechanism according to claim 1, characterised in that the locking element (140), provided with the locking limbs (138, 138') formed in the central area (115, 115') of the slide (114, 114') is V-shaped, and comprises on its central part (133) the locking cam (137), which is provided with two locking surfaces (135, 135') and faces the pinion (80).

5. Stepping switch mechanism according to claim 4, characterised in that the two locking limbs (138, 138') of the locking element (140) formed on the slides (114, 114') with flexible connecting points (119, 119') together form on the side facing the pinion (80), an angle of approximately 90°, and the two locking surfaces (135, 135') of the locking cam (137) engaged with the pinion (80) are arranged at an obtuse angle relative to each other.

6. Stepping switch mechanism according to claim 1, characterised in that the locking element (240), provided with the locking arms (236, 236') flexibly formed in the central area of the slide (214, 214'), is U-shaped and comprises on one locking curve (235) the two locking cams (237, 237') in spaced arrangement relative to each other and engaged with the pinion (280) with locking surfaces (234, 234').

7. Stepping switch mechanism according to claim 6, characterised in that a flexibly designed projection (262, 262') with wedge-shaped cams (263, 263') is formed on the end of the slide (214, 214'), which projection slides over a cam (264, 264') formed on the inside of the wall (259, 259') to define an action point when the pushbutton (221, 221') is actuated.

8. Stepping switch mechanism according to one of the claims 1 to 7, characterised in that the drive (30; 130 ; 230) with the locking element (40 ; 140 ; 240), formed in each case in a subtan- tially flexible manner, are designed for a rotary movement of the symbol carrier (79 ; 279) in the direction of the respectively actuated pushbutton (21, 21' ; 221, 221').

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