Foot switch

Abstract

The invention relates to a foot switch with a housing (1) and a pedal (3) which is pivotally mounted on a bearing axis (16) relative to the housing (1), wherein upon pivoting in an actuating direction from a rest position, the pedal (3) acts on a spring-biased switching unit (2), and wherein the pedal (3) can be pivoted beyond the rest position into a cleaning position, counter to the actuating direction.The foot switch is characterized in that at least one fixed sleeve (41, 43) and at least one rotary sleeve (42, 44) are arranged axially next to one another on the bearing axis (16), wherein the fixed sleeve (41, 43) is rotationally fixed to the housing (1) and the rotary sleeve (42, 44) is rotationally fixed to the pedal (3), and wherein the fixed sleeve (41, 43) and the rotary sleeve (42, 44) each have at least one run-on slope (413, 433, 423, 443) which slide on one another in at least one pivoting angle range which is located between the rest position and the cleaning position, as a result of which the fixed sleeve (41, 43) and the rotary sleeve (42, 44) move axially away from one another against a spring force when the pedal (3) is moved counter to the actuation direction.

Description

[0001] The invention relates to a foot switch with a housing and at least one pedal which is pivotally mounted on a bearing axis relative to the housing, wherein upon pivoting in an actuating direction from a rest position the pedal acts against a restoring force on a switching unit and wherein the pedal can be pivoted counter to the actuating direction beyond the rest position into a cleaning position.

[0002] Foot switches with one or more pedals are used in many applications. They are usually designed to close or open an electrical circuit when pressed with the foot, or alternatively or additionally output a signal whose value is functionally related to the pedal position. The value can be output in analog and / or digital format.

[0003] In many industrial or medical applications, it is desirable to be able to move the pedal past its rest position in the opposite direction of actuation. Foot switches are often designed so that the pedal is swung downward with the foot for actuation. Moving it in the opposite direction of movement then corresponds to folding the pedal up, making the space beneath the pedal more accessible for cleaning.

[0004] The pedal is actuated against a restoring force, which is applied, for example, by a spring in the switching unit of the foot switch. This can, for example, have a spring-loaded plunger that transmits the pedal actuation to an electrical contact set or an electrical position sensor.

[0005] The ability of the pedal to move beyond its rest position in the opposite direction to the direction of actuation means that there can be no fixed stop in the rest position. This in turn means that if, for example, someone slips off the pedal or if pressure is quickly released from the pedal, the pedal will spring up beyond its rest position due to the restoring force. For example, the pedal could move into the cleaning position and possibly remain there without returning to the usual rest position expected for the next actuation. Even if this does not happen, the movement beyond the rest position and the return to the rest position is associated with noise that can be annoying.

[0006] From the document US 10 338 626 B2, a foot switch of the type mentioned above is known with a pedal that can be operated with the foot from a rest position and can be pivoted upwards beyond the rest position into a cleaning position. A movable roller is arranged in the pedal itself, which is pushed out of the pedal below the treadle in a direction toward the bearing axis under spring force. This spring-loaded roller runs along a surface formed on a housing of the foot switch. This surface has a lug in the rest position area, which the roller must overcome in order to pivot the pedal upwards beyond the rest position into the cleaning position.The interaction of the spring-loaded roller in the pedal and the surface with the aforementioned lug on the foot switch housing prevents or at least significantly suppresses any overshoot of the pedal beyond its rest position, for example, when slipping off the pedal. In addition, the shape of the surface below the lug can generate a restoring force for the pedal, and the shape of the surface above the lug can define a locking position for the cleaning position.

[0007] However, the arrangement of the spring-loaded roller in the pedal results in a more complex pedal design. Furthermore, a correspondingly designed foot switch housing is required to provide the required rolling track for the roller. The solution described in the publication is therefore complex to implement and not well-suited for retrofitting an existing foot switch with a non-overshooting pedal.

[0008] It is therefore an object of the present invention to provide a foot switch of the type mentioned above that, while being simple in design, effectively suppresses overshoot of the pedal beyond its rest position, for example, after slipping off the pedal. The proposed solution should also be suitable as a retrofit solution for existing foot switches.

[0009] This problem is solved by a foot switch having the features of the independent claim. Advantageous embodiments and further developments are the subject of the dependent claims.

[0010] A foot switch according to the invention of the type mentioned at the outset is characterized in that at least one fixed sleeve and at least one rotary sleeve are arranged axially next to one another on the bearing axis, wherein the fixed sleeve is rotationally fixed to the housing and the rotary sleeve is rotationally fixed to the pedal, and wherein the fixed sleeve and the rotary sleeve each have at least one run-on bevel which slide against one another in at least one pivoting angle range which is located between the rest position and the cleaning position, as a result of which the fixed sleeve and the rotary sleeve move axially away from one another against a spring force when the pedal is moved counter to the actuating direction. It is noted that in the context of the present application, a "rotationally fixed coupling" is also understood to mean a connection in which a certain rotational play, e.g. due to tolerances, is present.

[0011] If a user slips off the pedal while actuating it, the pedal is initially accelerated towards the rest position by the restoring force. There, however, the pedal is stopped by the colliding and sliding run-on slopes of the at least one fixed sleeve and the at least one rotating sleeve and the spring force acting axially between them, and is pressed back into the rest position without swinging significantly beyond the rest position. Nevertheless, it is possible to manually pivot the pedal beyond the rest position into the cleaning position. The axial spring forces that must be overcome in this process also cause the pedal to move completely back into the rest position when pivoted back from the cleaning position.

[0012] The arrangement of the rotating sleeve and the fixed sleeve on the axis is space-saving and can be easily retrofitted, since no special design of the housing is required and retrofitting is therefore possible without modifying an existing housing.

[0013] In an advantageous embodiment of the foot switch, two fixed sleeves and two rotating sleeves are arranged on the bearing axis, with a compression spring preferably arranged between the two rotating sleeves on the bearing axis, and the two fixed sleeves each arranged on the outside next to the rotating sleeves. This arrangement allows the rotating sleeves to exert central and thus symmetrical forces on the pedal.

[0014] In a further advantageous embodiment of the foot switch, the at least one fixed sleeve is positioned adjacent to a bearing block for the bearing axis and is rotationally fixedly coupled to the bearing block. Preferably, the bearing block and the fixed sleeve are rotationally fixedly coupled via a locking pin engaging in a locking bore.

[0015] In a further advantageous embodiment of the foot switch, at least one driver surface is formed on the circumference of the at least one rotary sleeve, which bears against a driver web of the pedal in order to couple the at least one rotary sleeve to the pedal in a rotationally fixed manner.

[0016] The two designs mentioned above, for coupling the fixed sleeve to the housing or the rotating sleeve to the pedal in a rotationally fixed manner, can be implemented without any significant material expenditure and are also well suited for the design in which two fixed sleeves and two rotating sleeves are arranged on the bearing axis.

[0017] In a further advantageous embodiment of the foot switch, the run-up slope is formed on the front side of pockets or pins of the at least one fixed sleeve and the at least one rotary sleeve. The run-up slopes preferably touch each other when the pedal is in the rest position and move away from each other in the circumferential direction when the pedal is moved in the actuation direction. In this embodiment, the arrangement of the fixed and rotary sleeves has no influence on the pedal, except for minimal frictional forces that occur between them, and thus does not impede its actuation.

[0018] Further preferably, when the pedal is moved in the opposite direction to the actuation direction, the ramps slide against each other in an angular range immediately adjacent to the rest position. Thus, the suppression of overshoot effectively begins immediately from the rest position.

[0019] In a further advantageous embodiment of the foot switch, the run-on slopes no longer touch when the pedal is moved counter to the actuation direction beyond the angular range, whereby the angular range ends before the cleaning position. This advantageously means that no restoring forces act on the pedal in the cleaning position. However, an axially arranged spring between the fixed sleeve and the rotating sleeve is compressed more strongly than it is in the rest position of the pedal or in the actuation position. The frictional force acting between the at least one fixed sleeve and the at least one rotating sleeve is thereby increased, whereby the pedal is held in the cleaning position, but can easily be pivoted back down into the rest position.

[0020] The invention is explained in more detail below using an exemplary embodiment and the accompanying figures. The figures show: Fig. 1a a foot switch with a pedal in rest position in a longitudinal section; Fig. 1b, c the foot switch off Fig. 1a in two different cross sections; Fig. 1d a damping device of the foot switch in a spatial detailed representation; Fig. 2a-d the foot switch of the Fig. 1a-d in the same representation with its pedal in cleaning position; and Fig. 3 a spatial exploded view of the pedal and the damping device of the foot switch.

[0021] The figures show an exemplary embodiment of a foot switch comprising a housing 1, a switching unit 2, and a pedal 3 acting on the switching unit 2, in various views and in various operating states. In all figures, the same reference numerals identify the same elements. For reasons of clarity, not all elements are provided with a reference numeral in all figures.

[0022] In Fig. Figure 1a shows a longitudinal section through the foot switch. It has a housing 1 composed of a lower housing section 11, also referred to as base 11 below, and an attached upper housing section 17, also referred to as cover 17 below. The base 11 and the cover 17 can each be made in one piece or in multiple parts from plastic or metal. A combination is also conceivable, in which, for example, the base 11 is made from metal, e.g., aluminum or zinc, using a die-casting process, and the cover 17 is made from plastic and produced using an injection-molding process. The housing 1 has housing feet 12 on its base 11.

[0023] In the example shown, the cover 17, in its front section facing the user, merges into a protective hood 18 that covers the pedal 3. An opening 19 is provided at the front to allow the pedal 3 to be operated with the foot. It is understood that a foot switch according to the application can also be designed without the protective hood 18 shown.

[0024] The pedal 3 is pivotally mounted on the housing 1 about a bearing axis 16. In the illustrated embodiment, the pedal 3 is mounted on the base 11 of the housing 1, with the bearing axis 16 being guided by two bearing blocks 15 mounted on the base 11. In alternative embodiments, the bearing blocks can also be formed directly on the base 11. It is also possible to mount the pedal 3 on the cover 17 instead of the base 11. In the illustrated embodiment, one pedal 3 is provided, but it is also possible for several pedals 3 to be arranged side by side.

[0025] The pedal 3 has a tread 31 on which the user's foot rests when using the foot switch, allowing the user to press the pedal 3 down with the foot to actuate the foot switch. Below the tread 31, a downwardly projecting switching lever 32 is formed on the pedal 3. This switch lever transmits the actuation movement of the pedal 3 to the switching unit 2, which is mounted in a receptacle 13 on or in the base 11.

[0026] In the Fig. 1a shows a longitudinally displaceable plunger 21 of the switching unit 2, against which the switching lever 32 rests and which, when the foot switch is actuated by the switching lever 32, is pressed in against the restoring force of a return spring 22. In the illustrated embodiment, the return spring 22 provides the restoring force for the pedal 3 via the plunger 21. Alternatively or additionally, at least one further spring may be present to apply the restoring force acting between the housing 1 and the pedal 3.

[0027] An interior space 14 is formed in the base 11 behind the pedal 3, as viewed by the user, and is covered by the cover 17. Located within this interior space 14 is a contact set of the switching unit 2 or a position sensor that determines the position of the plunger 21 and thus detects actuation of the foot switch. Additional electrical or electronic components can be arranged in the interior space 14 to evaluate the contact set or the position sensor of the switching unit 2. Furthermore, connections (not shown here) can be provided that protrude into the interior space 14 if the foot switch is operated with a wired connection. It is also conceivable for a radio transmission module to be arranged in the interior space 14, along with batteries for its power supply, if the radio switch is operated wirelessly.

[0028] In the Fig. 1b and Fig. 1c shows a cross-section and a partially cut cross-section through the foot switch 1, respectively, showing the arrangement of the bearing blocks 15 on the base 11 and the positioning of the bearing axis 16 and the pedal 3. Reference is further made to Fig. 3, which shows the pedal 3 and its bearing in a spatial exploded view.

[0029] Fig. 3 shows that bearing bores 151 are formed in the bearing blocks 15, through which the bearing spindle 16 extends. It is noted that, in the context of the application, the term "bore" refers to a cylindrical through-hole or blind hole, regardless of whether this was actually created by a drilling process or another forming step. Bearing pins 33 are formed on the underside of the pedal 3, which also have a bore through which the bearing spindle 16 extends. In the example shown, the bearing spindle 16 is fixed in the bearing pin 33 by means of stud bolts 34. It is also conceivable to fix the bearing spindle 16 in one or both of the bearing blocks 15 and not in the bearing pin 33.

[0030] The view of the Fig. 3 further shows a downwardly projecting stop 35, with which the pedal 3 rests on the base 11 when it is fully depressed. The stop 35 prevents excessive forces from being exerted on the switching unit 2 via the shift lever 32.

[0031] According to the application, a damping device 4 is arranged on the bearing axis 16 between the bearing blocks 15, which damping device prevents the pedal 3 from swinging upwards beyond its rest position if, for example, a user slips his foot off the tread 31 when actuating the foot switch.

[0032] This damping device 4 is in Fig. 1d reproduced in the assembled state. Fig. 3 shows the structure and components of the damping device 4 in an exploded view.

[0033] In the example shown, the damping device 4 has four sleeves 41-44 arranged side by side between the bearing blocks 15 on the bearing axis 16. Each of the sleeves 41-44 has a central bore 411, 421, 431, or 441, through which the bearing axis 16 passes. The two outer sleeves 41 and 43 are mounted in a rotationally fixed manner to the bearing block 15 by each having a locking pin 412 and 432, respectively, which engages in a corresponding locking bore 152 of the bearing block 15. These sleeves 41 and 43 are also referred to below as fixed sleeves 41, 43.

[0034] The two inner sleeves 42 and 44 have flat driver surfaces 424 and 444 on their circumference, with which they rest against at least one driver web 36 of the pedal 3. In this way, the sleeves 42, 44 are coupled to the pedal 3 in a rotationally fixed manner. Since the pedal can pivot relative to the base, the sleeves 42 and 44 also pivot relative to the base and, to distinguish them from the fixed sleeves 41, 43, are hereinafter also referred to as rotary sleeves 42, 44. In the illustrated embodiment, two driver surfaces 424 and 444 are formed parallel to one another and opposite one another on each rotary sleeve 42, 44, and correspondingly, two opposing driver webs 36 are also formed on the pedal 3.

[0035] A compression spring 45 is arranged between the two rotary sleeves 42 and 44, which presses the two sleeves 42, 44 away from each other in the axial direction. A cup-shaped spring receptacle 422, into which the spring 45 engages, can be seen in the rotary sleeve 42. A comparable spring receptacle is also present in the rotary sleeve 44, but is not visible in the illustration. In addition, the rotary sleeve 44 has a circumferential collar 442 that surrounds the spring 45 on the outside and can be inserted into the spring receptacle 422 of the rotary sleeve 42. The collar 442 prevents dust or other particles from penetrating the area of ​​the compression spring 45.

[0036] The rotary sleeves 42 and 44 have axially outwardly projecting pins that engage corresponding pockets of the fixed sleeves 41 and 43, respectively. The pins are provided with run-up slopes 423 and 443, and the pockets of the fixed sleeves 41 and 43 are provided with corresponding run-up slopes 413 and 433. It is understood that in an alternative embodiment, the rotary sleeves 42, 44 may have the pockets and the fixed sleeves 41, 43 may have the pins.

[0037] From the presentation of the Fig. 1d, which shows the damping device 4 in the assembled state, it can be seen that the pockets in the fixed sleeves 41, 43 are somewhat larger in terms of their angular range than the pins of the rotating sleeves 42 and 44. Accordingly, the rotating sleeves 42, 44 can rotate within a certain angular range relative to the fixed sleeves 41, 43 before the run-up slopes 413 and 423 or 433 and 443 lie on top of one another. This angle corresponds exactly to the freedom of movement of the pedal 3 between a rest position and an actuated position, i.e., the position in the actuated state.

[0038] In Fig. Figure 1d shows the relative position of the fixed and rotating sleeves 41-44 in the actuated state. In the resting state, the ramps 413 and 423, or 433 and 443, would just touch each other. Within this angular range, which corresponds to the movement of the pedal 3 between its rest position and the actuated position, the damping device 4 has no influence on the pedal 3, except for minimal frictional forces that occur between the fixed sleeves 41 and 43 and the rotating sleeves 42, 44.

[0039] In addition to moving the pedal 3 between the rest position and the actuated position, it is also possible to move the pedal 3 upwards beyond the rest position, i.e., opposite to the actuated direction, in order to bring the pedal 3 into a cleaning position. The foot switch is in the Fig. 2a-d in the same way as in Fig. 1a-d with pedal 3 in this cleaning position.

[0040] When the pedal 3 is moved upwards beyond its rest position, the rotary sleeves 42 and 44 rotate so that the run-up slopes 413 and 423 or 433 and 443 slide against each other, thereby pushing the rotary sleeves 42 and 44 towards each other against the spring force of the compression spring 45. When moving the pedal 3 upwards, in particular, the angular range in which the run-up slopes 413 and 423 or 433 and 443 slide against each other must be overcome. Upon further movement, the protruding pin of the respective rotary sleeve 42, 44 moves on the end face of the respective fixed sleeve 41, 43 without the spring 45 being compressed further. Fig. Figure 2d shows this state of the damping device 4, which is preferably reached at the latest in the cleaning position of the pedal 3. Then, no more restoring forces of the compression spring 45 act on the pedal 3, but the compression spring 45 is more strongly compressed than it is in the rest position of the pedal 3 or in the actuating position according to Fig.1d. The frictional force acting between the fixed sleeves 41 and 43 and the rotating sleeves 42 and 44 is thus increased, whereby the pedal 3 is held in the cleaning position, but can easily be pivoted back down into the rest position. Shortly before reaching the rest position, the ramps 413 and 423, or 433 and 443, slide onto each other again and actively move the pedal 3 back into the rest position. The damping device 4 shown thus enables pivoting up into the cleaning position and ensures that the pedal pivots back completely into the rest position.

[0041] In addition, the damping device 4 dampens any overshoot of the pedal 3 if a user slips off the tread 31 during actuation. The pedal 3 is then initially accelerated by the restoring forces of the return spring 22 via the plunger 21 toward the rest position, but is stopped there by the converging and sliding run-up slopes 413 and 423 or 433 and 443 and the restoring forces of the compression spring 45 and pressed back into the rest position without oscillating significantly beyond the rest position.

[0042] The illustrated arrangement of the damping device 4 on the bearing axis 16 between the bearing blocks 15 allows for easy retrofitting of such a damping device. The use of the damping device 4 requires only appropriately designed bearing blocks 15, which provide the locking bore 152, and a correspondingly designed pedal 3, which has at least one driver web 36. No modifications are required to the base 11 or the cover 17 of the foot switch.

[0043] The design also allows the restoring forces preventing or minimizing overshoot, with which the pedal 3 is moved back to the rest position, to be varied and thus suitably adjusted in a simple manner by varying the spring preload or spring constant of the compression spring 45 and the gradients of the run-up slopes 413, 423, 433, 443. List of reference symbols 1 housing 11 Lower housing part (base) 12 Housing base 13 Recording 14 Interior 15 bearing block 151 bearing bore 152 locking hole 16 bearing axis 17 Upper housing part (cover) 18 Protective cover 19 Opening 2 switching unit 21 plungers 22 Return spring 3 Pedal 31 Tread 32 gear levers 33 bearing journals 34 Stud screw 35 stop 36 Carrier bar 4 Damping device 41 Fixed sleeve 411 Central bore 412 locking pin 413 ramp 42 rotating sleeve 421 central bore 422 spring retainer 423 ramp 424 Driving surface 43 additional fixed sleeves 431 central bore 432 locking pin 433 ramp 44 additional rotating sleeves 441 Central bore 442 collar 443 ramp 444 Driving surface 45 compression spring

Claims

[1] Foot switch with a housing (1) and a pedal (3) which is pivotally mounted on a bearing axis (16) relative to the housing (1), wherein, when pivoted in an actuating direction from a rest position, the pedal (3) acts on a spring-loaded switching unit (2) and wherein the pedal (3) can be pivoted beyond the rest position into a cleaning position in the opposite direction to the actuating direction, characterized byin that at least one fixed sleeve (41, 43) and at least one rotary sleeve (42, 44) are arranged axially next to one another on the bearing axis (16), the fixed sleeve (41, 43) being rotationally fixed to the housing (1) and the rotary sleeve (42, 44) being rotationally fixed to the pedal (3), and the fixed sleeve (41, 43) and the rotary sleeve (42, 44) each having at least one run-on bevel (413, 433, 423, 443) which slide on one another in at least one pivoting angle range which is located between the rest position and the cleaning position, as a result of which the fixed sleeve (41, 43) and the rotary sleeve (42, 44) move axially away from one another against a spring force when the pedal (3) moves counter to the actuating direction. [2] Foot switch according to claim 1, wherein the two fixed sleeves (41, 43) and two rotating sleeves (42, 44) are arranged on the bearing axis (16). [3] Foot switch according to claim 2, wherein a compression spring (45) is arranged between the two rotary sleeves (42, 44) on the bearing axis (16) and the two fixed sleeves (41, 43) are each arranged outside next to the rotary sleeves (42, 44). [4] Foot switch according to one of claims 1 to 3, wherein the at least one fixed sleeve (41, 43) is positioned adjacent to a bearing block (15) for the bearing axis (16) and is coupled to the bearing block (15) in a rotationally fixed manner. [5] Foot switch according to claim 4, wherein the bearing block (15) and the fixed sleeve (41, 43) are coupled in a rotationally fixed manner via a locking pin (412, 432) engaging in a locking bore (152). [6] Foot switch according to one of claims 1 to 5, in which at least one driver surface (424, 444) is formed on the circumference of the at least one rotary sleeve (42, 44), which driver surface bears against a driver web (36) of the pedal (3) in order to couple the at least one rotary sleeve (42, 44) to the pedal (3) in a rotationally fixed manner. [7] Foot switch according to one of claims 1 to 6, in which the run-up slope (413, 433, 423, 443) is formed on the end face of pockets or pins of the at least one fixed sleeve (41, 43) and the at least one rotary sleeve (42, 44). [8] Foot switch according to one of claims 1 to 7, in which the run-up slopes (413, 433, 423, 443) touch each other in the rest position of the pedal (3) and move away from each other in the circumferential direction when the pedal (3) is moved in the actuating direction. [9] Foot switch according to claim 8, wherein the run-up slopes (413, 433, 423, 443) slide on one another when the pedal (3) moves counter to the actuating direction in an angular range which immediately follows the rest position. [10] Foot switch according to claim 9, wherein the run-up slopes (413, 433, 423, 443) no longer touch each other when the pedal (3) is moved counter to the actuating direction beyond the angular range. [11] Foot switch according to claim 9 or 10, wherein the angular range ends before the cleaning position.

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