END SWITCH
Patent Information
- Application Number
- DE112019001264
- Authority / Receiving Office
- DE · DE
- Patent Type
- Patents
- Current Assignee / Owner
- Priority Date
- 2018-03-14
- Filing Date
- 2019-03-05
- Publication Date
- 2025-02-13
- Estimated Expiration
- 2039-03-05
Smart Images
Figure 00000000_0000_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The present disclosure relates to a limit switch. STATE OF THE ART
[0002] Patent Document 1 discloses a limit switch provided with a housing in which a switch is housed. This limit switch includes a shaft extending from the outside to the inside of the housing and pivotally supported by the housing, and an arm connected to the end of the shaft on the outer side of the housing and capable of pivoting the shaft. EP 2 874 168 A2 discloses a limit switch having a pivot shaft connected to a first and a second cam. The two cams are held apart by the tension of a spring. When no external force acts on the pivot shaft, the spring causes the respective cam to move to a neutral position in which the spring is relaxed. In order to be able to move the two cams relative to each other, rotation limiting parts are arranged such that the other cam cannot be moved beyond the neutral position.US 3287516 A describes a limit switch with an external actuating element that activates the switching units in the limit switch housing in response to an externally applied force. The actuating element is mounted on the housing in an explosion-proof manner and is connected to two cams, each of which can only pivot in one direction.
[0003] US 2014 / 0374224 A1 discloses a limit switch with a pivoting shaft and two cams attached to it to switch a contact mechanism on and off.
[0004] US Pat. No. 5,028,748 A discloses a limit switch with a rotating shaft to which a cam is attached, driving an actuating plunger to switch the switching unit on or off depending on the actuation of the actuating lever. Elastic stoppers are mentioned in two different forms: a spring-loaded cylinder or a U-shaped plateau stopper. Both of these stoppers are designed to prevent one cam from over-rotating by preventing the cam from being rotated back further than the free position.
[0005] JP H04 - 324 213 A describes a limit switch with two cams, each with a projection that can be held apart by a spring. PRIOR ART DOCUMENT PATENT DOCUMENT
[0006] Patent Document 1: JP 2015-204223 A. SUMMARY OF THE INVENTION OBJECTS TO BE SOLVED BY THE INVENTION
[0007] Some of the limit switches described above are configured such that the arm extends in a direction perpendicular to the shaft, has one end in the extending direction of the arm fixed to the shaft, and can pivot with respect to the shaft between three positions in the circumferential direction (ie, an intermediate return position in which the limit switch is turned off, and a first travel end position and a second travel end position at both ends in which the limit switch is turned on).
[0008] In such a limit switch, the arm is positioned in the return position by the excitation force of a coil spring or the like, so that the arm may swing in the return position instead of stopping immediately, and it may not be possible to accurately determine the return position. In this case, the return position varies for each limit switch, and it may not be possible to operate the limit switch accurately.
[0009] An object of the present disclosure is to provide a limit switch that can be accurately operated. MEANS FOR SOLVING THE OBJECTS
[0010] An example of the limit switch of the present disclosure includes: a switch body with a contact mechanism inside and an operating unit connected to the switch body. The operating unit contains a housing body connected to the switch body, a pivot shaft extending from an outer side of the housing body to an inner side of the housing body and pivotable about an extending direction of the pivot shaft; a bearing provided in the housing body and pivotally supporting the pivot shaft, an operating lever which is connected to the pivot shaft outside the housing body and is pivotable together with the pivot shaft between an intermediate return position and a first end of movement position and a second end of movement position, wherein the intermediate return position and the two movement end positions are arranged at intervals in a circumferential direction with respect to the extension direction of the pivot shaft, an annular first cam connected to the pivot shaft within the housing body and including a first transmitter that pivots together with the pivot shaft to switch the contact mechanism on or off when the operating lever pivots from the intermediate return position to the first end of travel position, wherein the first transmitter does not pivot together with the pivot shaft when the operating lever pivots from the intermediate return position to the second end of travel position, wherein the first cam allows the pivoting of the pivot shaft when the first transmitter does not pivot, an annular second cam connected to the pivot shaft with a gap from the first cam in the extending direction of the pivot shaft and arranged symmetrically with the first cam with respect to the pivot shaft within the housing body, and including a second transmitter that pivots together with the pivot shaft to switch the contact mechanism on or off when the operating lever pivots from the intermediate return position to the second movement end position, wherein the second transmitter does not pivot together with the pivot shaft when the operating lever pivots from the intermediate return position to the first movement end position, wherein the second cam allows the pivoting of the pivot shaft when the second transmitter does not pivot, an elastic member provided within the housing body, regulating the operating lever from the first movement end position toward the intermediate return position via the pivot shaft and the first cam, and regulating the operating lever from the second movement end position toward the intermediate return position via the pivot shaft and the second cam, a pivot limiting part of a first cam provided within the housing body and limiting the pivoting of the first cam in a first direction in which the operating lever moves from the intermediate return position to the second movement end position, and a pivot limiting part of a second cam provided within the housing body and limiting pivoting to the second cam in a second direction in which the operating lever moves from the intermediate return position to the first movement end position.
[0011] The pivot limiting member of the first cam comprises a first elastic stopper which cooperates with the first cam in a direction perpendicular to the pivot shaft in a state in which the operating lever is in the intermediate return position to limit the pivoting of the first cam in the first direction, and the pivot limiting part of the second cam includes a second elastic stopper that cooperates with the second cam in a direction perpendicular to the pivot shaft in a state where the operating lever is in the intermediate return position to limit the pivoting of the second cam in the second direction.
[0012] A limit switch may be configured such that the pivot shaft to which the first cam, the second cam, and the elastic member are connected has a substantially semi-arc shape in cross section along the direction perpendicular to the extending direction of the pivot shaft and is formed with a locking surface to which locking projections of the first cam and the second cam are locked.
[0013] A limit switch may further be configured such that a spring locking member for locking a first end of the elastic member is provided on a first contact surface of the first transmitter with respect to the pivot shaft, and that on a second contact surface of the second transmitter with respect to the pivot shaft, a spring locking member for locking a second end (632) of the elastic member is provided. EFFECTS OF THE INVENTION
[0014] According to the limit switch, the operating unit includes: an elastic member that regulates the operating lever from the first movement end position toward the intermediate return position or return position via the pivot shaft and the first cam, and regulates the operating lever from the second movement end position toward the return position via the pivot shaft and the second cam; a first cam pivot limiting member that limits the pivoting of the first cam in a first direction in which the operating lever moves from the return position to the second movement end position; and a second cam pivot limiting member that limits the pivoting of the second cam in a second direction in which the operating lever moves from the return position to the first movement end position.The elastic part, the swing limiting part of the first cam, and the swing limiting part of the second cam can reduce the swing of the operating lever in the return position to instantly stop the operating lever in the return position. As a result, it is possible to achieve the limit switch, which can reduce the variation in the return position of the operating lever and operate accurately. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a perspective view of a limit switch according to an embodiment of the present disclosure. Fig. Fig. 2 is a perspective view showing an operation unit in a state where an operation lever of the limit switch is Fig. 1 was removed. Fig. 3 is a sectional view taken along a line III-III in Fig. 2 is taken. Fig. Fig. 4 is a perspective view showing the operation unit in a state where a housing and an operation lever of the limit switch are Fig. 1 were removed. Fig. 5 is a sectional view taken along a line VV in Fig. 2 is taken. Fig. 6 is a sectional view taken along a line VI-VI in Fig. 4 is taken. Fig. 7 is a sectional view taken along a line VII-VII in Fig. 4 is taken. Fig. Fig. 8 is a sectional view of an embodiment not according to the invention taken along a line VIII-VIII in Fig. 2 is taken. Fig. 9 is a front view showing a first modification of the limit switch of Fig. 1 represents. Fig. 10 is a sectional view taken along the line III-III in Fig. 2, which is a second modification of the limit switch from Fig. 1 represents. Fig. 11 is a sectional view taken along the line VIII-VIII in Fig. 2, the inventive embodiment of the limit switch from Fig. 1 represents. MODES FOR CARRYING OUT THE INVENTION
[0015] Hereinafter, an example of the present disclosure will be described with reference to the accompanying drawings. In the following description, terms indicating specific directions or positions (e.g., terms such as "top," "bottom," "right," and "left") are used as necessary, but the use of these terms is intended to facilitate understanding of the present disclosure with reference to the drawings, and the technical scope of the present disclosure is not limited by the meaning of these terms. The following description is essentially illustrative only and is not intended to limit the present disclosure, its application, or uses. Furthermore, the drawings are schematic, and the relationship of each dimension or the like does not necessarily correspond to an actual one.
[0016] As in Fig. 1, a limit switch 1 according to an embodiment of the present disclosure is provided with a switch body 2 having a contact mechanism (not shown) inside, and an operation unit 3 detachably connected to the switch body 2.
[0017] As in Fig. 1, the switch body 2 has a hollow, substantially rectangular parallelepiped shape and the operating unit 3 is connected to one of the side surfaces facing each other in the longitudinal direction (ie the upper surface in Fig. 1).
[0018] As in Fig. 1, the operating unit 3 includes: a housing 10; a pivot shaft 20 extending from the outside of the housing 10 to the inside of the housing 10 and pivotable about the extending direction of the pivot shaft 20; a bearing 30 (see FIG. Fig. 3) provided in the housing and pivotally supporting the pivot shaft 20; and an operating lever 40 connected to the pivot shaft 20 outside the housing 10.
[0019] As in Fig. As shown in Figure 2, the housing 10 includes a hollow, substantially cubic housing body 11 connected to the switch body 2, and a peripheral wall 12 provided on a surface of the housing body 11. The housing body 11 is provided with the bearing 30, and the pivot shaft 20, which extends from the outside of the housing body 11 to the inside of the housing body 11, is pivotally supported by the bearing 30. The peripheral wall 12 has, for example, a substantially cylindrical shape and surrounds the bearing 30 around the pivot shaft 20 outside the housing body 11, as shown in Fig. 3 shown.
[0020] As in Fig. 2, the pivot shaft 20 has a substantially columnar shape and is configured to be pivotable about its extending direction.
[0021] As in Fig. 3, the pivot shaft 20 includes a projection 21 extending in a radial direction with respect to the pivot shaft 20 and a recess 22 extending in a direction intersecting (e.g., perpendicular to) the extending direction of the pivot shaft 20 for accommodating and holding the projection 21. The projection 21 is configured by a separate member from that of the pivot shaft 20, and a part of the projection 21 is press-fitted into the recess 22 to be accommodated and held therein. Each of the projection 21 and the recess 22 is closer to the inside of the housing body 11 than a later-described sealant 13 in the extending direction of the pivot shaft 20, and the projection 21 is arranged to contact a pivot limiting part 31 of the bearing 30 described later in the circumferential direction of the pivot shaft 20.That is, the pivoting of the projection 21 about the pivot shaft 20 is limited by the pivot limiting part 31 of the bearing 30 to define the pivoting range of the pivot shaft 20.
[0022] As in Fig. 3, the bearing 30 is provided in the housing body 11 and the end of the housing body 11 is surrounded by the peripheral wall 12, which end is further away from the inside of the housing body 11. As shown in Fig. 4, the bearing 30 has a substantially cylindrical shape capable of pivotally supporting the pivot shaft 20, and the pivot limiting member 31 is provided at the end of the housing body 11, the end being farther from the inside of the housing body 11.
[0023] As in Fig. 5, the pivot limiting member 31 is configured by a notch extending in the circumferential direction with respect to the pivot shaft 20, and a first end 32 and a second end 33 in the circumferential direction with respect to the pivot shaft 20 contact the projection 21 of the pivot shaft 20 to limit the pivoting of the projection 21 of the pivot shaft 20 about the pivot shaft 20.
[0024] It should be noted that the sealing means 13 is provided inside the peripheral wall 12 and at the end of the housing body 11, the end being farther from the inside in the extending direction of the pivot shaft 20 than the bearing 30. The sealing means 13 is configured by, for example, an oil seal and seals the inside of the housing body 11.
[0025] As in Fig. 1, the operating lever 40 is disposed outside the housing body 11 and extends in a direction intersecting (e.g., perpendicular to) the pivot shaft 20. One end of the operating lever 40 in the extending direction thereof is connected to the pivot shaft 20 such that the pivot shaft 20 can be pivoted along with the pivoting of the operating lever 40. At the other end of the operating lever 40 in the extending direction thereof, a roller 41 is provided so as to be pivotable about a pivot axis L substantially parallel to the pivot shaft 20.
[0026] As in Fig. As shown in Figure 2, the operating lever 40 is configured to be pivotable between an intermediate return position P1, which is arranged at intervals in the circumferential direction with respect to the extending direction of the pivot shaft 20, and a first movement end position P2 and a second movement end position P3 at both ends, respectively. In the limit switch 1, the return position P1, the first movement end position P2, and the second movement end position P3 are arranged at a distance of approximately 90 degrees from each other in the circumferential direction around the pivot shaft 20. Fig. 2, a center line extending in the extending direction of the operating lever 40 is indicated by a dotted line.
[0027] As in Fig. 1, the operating lever 40 is at the return position P1 in a state where no external force is applied. At this time, the operating lever 40 extends in a direction away from the switch body 2 along the longitudinal direction of the switch body 2 from the pivot shaft 20. In a state where the operating lever 40 is at the return position P1, the contact mechanism in the switch body 2 is turned off.
[0028] On the other hand, when an external force is applied to the operating lever 40 in the circumferential direction with respect to the pivot axis L, the operating lever 40 pivots together with the pivot shaft 20 from the return position P1 to the first movement end position P2 or the second movement end position P3. By pivoting the operating lever 40, a first cam 61 and a second cam 62, described later, connected to the pivot shaft 20 pivot, and the contact mechanism in the switch body 2 is switched from off to on. That is, the operating lever 40 is configured to pivot the pivot shaft 20 to turn the contact mechanism on and off.
[0029] As in Fig. 5, in the limit switch 1, when the operating lever 40 is in the first movement end position P2, the projection 21 of the pivot shaft 20 contacts the first end 32 of the pivot limiting part 31 of the bearing 30 in the circumferential direction with respect to the pivot shaft 20. When the operating lever 40 is in the second movement end position P3, the projection 21 of the pivot shaft 20 contacts the second end 33 of the pivot limiting part 31 of the bearing 30 in the circumferential direction with respect to the pivot shaft 20.
[0030] Furthermore, as in Fig. 3, the operating unit 3 includes a pivot shaft support 50. The pivot shaft support 50 is provided around the pivot shaft 20 at a position inside the peripheral wall 12 and farther from the inside of the housing body 11 than the bearing 30 in the extending direction of the pivot shaft 20.
[0031] In particular, as in Fig. 4, the pivot shaft support 50 is configured by a substantially annular second bearing 51 disposed over the circumference of the pivot shaft 20. In a state where an external force along the extending direction of the pivot shaft 20 (ie, an external force F along the direction shown in Fig. 1) is not applied to the operating lever 40, the second bearing 51 allows the pivoting of the pivot shaft 20. In a state where the external force is applied to the operating lever 40 along the extending direction of the pivot shaft 20, an end 52 on the outer side in the radial direction with respect to the pivot shaft 20 contacts an inner peripheral surface 121 (shown in Fig. 3) the peripheral wall 12 to support the pivot shaft 20.
[0032] Furthermore, as in Fig. 3, the operating unit 3 includes the first cam 61 and the second cam 62, each connected to the pivot shaft 20 within the housing body 11, and an elastic member 63 provided within the housing body 11. The second cam 62 is arranged symmetrically with the first cam 61 with respect to the pivot shaft 20.
[0033] As in Fig. 6, the pivot shaft 20 to which the first cam 61, the second cam 62 and the elastic member 63 are connected has a substantially semi-arc shape in cross section along the direction perpendicular to the extending direction of the pivot shaft 20 and is formed with a locking surface 23 to which locking projections 613, 623 of the first cam 61 and a second cam 62 described later are locked.
[0034] As in Fig. 6, the first cam 61 includes a first transmitter 611 having an annular shape (including not only a completely annular shape but also a substantially annular shape provided with a notch), wherein the first transmitter 611 pivots together with the pivot shaft 20 to turn the contact mechanism on and off when the operating lever 40 pivots from the return position P1 to the first movement end position P2, wherein the first transmitter 611 does not pivot together with the pivot shaft 20 when the operating lever 40 pivots from the return position P1 to the second movement end position P3. That is, the first transmitter 611 transmits the power of the pivoting torque of the pivot shaft 20, which is generated by the operating lever 40 pivoting from the return position P1 to the first movement end position P2, to a drive component to turn the contact mechanism on and off.
[0035] A substantially circular through-hole 612 is provided at a substantial center of the first cam 61. On the inner peripheral surface of the through-hole 612, a locking projection 613 is provided, which locks with the locking surface 23 of the pivot shaft 20. With the locking projection 613, when the operating lever 40 pivots in a second direction B from the return position P1 toward the first movement end position P2, the first cam 61 pivots together with the pivot shaft 20, while when the operating lever 40 pivots in a first direction A from the return position P1 toward the second movement end position P3, the first cam 61 does not pivot together with the pivot shaft 20 and allows the pivoting of the pivot shaft 20 with respect to the first cam 61.
[0036] A first contact surface 614 is provided at the end of the first transmitter 611 on the downstream side in the second direction B in which the operating lever 40 moves from the return position P1 toward the first movement end position P2. As shown in Fig. 8, in an embodiment not according to the invention, the first contact surface 614 is arranged to contact a later-described first contact projection 71 in a state where the operating lever 40 is in the return position P1. Furthermore, on the opposite side of the first contact surface 614 of the first transmitter 611 with respect to the pivot shaft 20, a spring locking part 615 is provided for locking a first end 631 of the elastic part 63.
[0037] As in Fig. 7, the second cam 62 includes a second transmitter 621 having an annular shape (including not only a completely annular shape but also a substantially annular shape provided with a notch), wherein the second transmitter 621 pivots together with the pivot shaft 20 to turn the contact mechanism on and off when the operating lever 40 pivots from the return position P1 to the second movement end position P3, wherein the second transmitter 621 does not pivot together with the pivot shaft 20 when the operating lever 40 pivots from the return position P1 to the first movement end position P2. That is, the second transmitter 621 transmits the power of the pivoting torque of the pivot shaft 20 generated by the operating lever 40 pivoting from the return position P1 to the second movement end position P3 to a drive component to turn the contact mechanism on and off.
[0038] A substantially circular through-hole 622 is provided at a substantial center of the second cam 62. On the inner peripheral surface of the through-hole 622, a locking projection 623 is provided, which locks with the locking surface 23 of the pivot shaft 20. With the locking projection 623, when the operating lever 40 pivots in the first direction A from the return position P1 toward the second movement end position P3, the second cam 62 pivots together with the pivot shaft 20, while when the operating lever 40 pivots in the second direction B from the return position P1 toward the first movement end position P2, the second cam 62 does not pivot together with the pivot shaft 20 and allows the pivoting of the pivot shaft 20 with respect to the second cam 62.
[0039] A second contact surface 624 is provided at the end of the second transmitter 621 on the downstream side in the first direction A in which the operating lever 40 moves from the return position P1 to the second movement end position P3. As shown in Fig. 8, in an embodiment not according to the invention, the second contact surface 624 is arranged to contact a later-described second contact projection 72 in a state where the operating lever 40 is in the return position P1. Furthermore, on the opposite side of the second contact surface 624 of the second transmitter 621 with respect to the pivot shaft 20, a spring locking part 625 is provided for locking a second end 632 of the elastic part 63.
[0040] In the limit switch 1, the first contact surface 614 of the first cam 61 and the second contact surface 624 of the second cam 62 are each arranged on the same virtual plane perpendicular to the extending direction of the pivot shaft 20.
[0041] As in Fig. 4, the elastic member 63 is configured by a coil spring, disposed between the first cam 61 and the second cam 62, and connected to the pivot shaft 20 in a state where the first end 631 is locked with the spring locking part 615 of the first cam 61 and the second end 632 is locked with the spring locking part 625 of the second cam 62. The elastic member 63 regulates the operating lever 40 from the first movement end position P2 toward the return position P1 via the first cam 61 and the pivot shaft 20, and regulates the operating lever 40 from the second movement end position P3 toward the return position P1 via the second cam 62 and the pivot shaft 20.
[0042] The operating unit 3 includes a first cam swing limiting part and a second cam swing limiting part, each provided within the housing body 11.
[0043] As in Fig. 8, in an embodiment not according to the invention, the pivot limiting part of the first cam includes the first contact surface 614 of the first cam 61 and the first contact projection 71 connected to the housing body 11. The first contact projection 71 extends from the inside of the housing body 11 toward the first contact surface 614 and is configured to contact the first contact surface 614 when the operating lever 40 is in the return position P1, thereby limiting the pivoting of the first cam 61 in the first direction A in which the operating lever 40 moves from the return position P1 toward the second movement end position P3.
[0044] As in Fig. 8, in an embodiment not according to the invention, the pivot limiting part of the second cam includes the second contact surface 624 of the second cam 62 and the second contact projection 72 connected to the housing body 11. The second contact projection 72 extends from the inside of the housing body 11 toward the second contact surface 624 and is configured to contact the second contact surface 624 when the operating lever 40 is in the return position P1, thereby limiting the pivoting of the second cam 62 in the second direction B in which the operating lever 40 moves from the return position P1 toward the first movement end position P2.
[0045] Note that each of the first contact surface 614 and the second contact surface 624 is formed, for example, by crushing the downstream side end of the first transformer 611 in the first direction and the downstream side end of the second transformer 621 in the second direction.
[0046] In the limit switch 1, the operating unit 3 includes the pivot shaft support 50, which allows the pivot shaft 20 to pivot with respect to the housing body 11 in a state where an external force along the extending direction of the pivot shaft 20 is not applied to the operating lever 40, and contacts the peripheral wall 12 to support the pivot shaft 20 in a state where the external force along the extending direction of the pivot shaft 20 is applied to the operating lever 40. The pivot shaft support 50 can prevent the deformation of the pivot shaft 20 due to an external force along the extending direction of the pivot shaft 20, making it possible to reach the limit switch 1, which is less likely to fail.
[0047] The pivot shaft support 50 includes the annular second bearing 51 disposed over the circumference of the pivot shaft 20. This makes it possible to prevent deformation of the pivot shaft 20 at any position around the pivot shaft 20 due to an external force along the extending direction of the pivot shaft 20.
[0048] In the limit switch 1, the operation unit 3 includes the operation unit detachably connected to the switch body 2, and in the operation unit 3, the pivot shaft 20 includes the projection 21 extending in the radial direction with respect to the pivot shaft 20, and the bearing 30 includes the pivot limiting part 31 arranged around the pivot shaft 20 so as to be contactable with the projection 21 and limiting the pivoting of the projection 21 around the pivot shaft 20. That is, the limit switch 1 limits the pivoting of the pivot shaft 20 not at the inside of the switch body 2 or the operating unit 3, but at the pivot shaft 20 and the bearing 30, thereby limiting the pivoting of the operating lever 40.As a result, even if an external force of a magnitude greater than expected is applied to the operating lever 40 from the pivoting direction thereof, it is possible to prevent breakage of the drive component that turns the contact mechanism on and off, such as the cams 61, 62, and thus the limit switch 1 can be repaired, for example, by simply replacing the operating unit. That is, it is possible to achieve the limit switch 1 that is easy to repair and has high practicality.
[0049] The operating unit 3 includes the cylindrical peripheral wall 12 surrounding the bearing 30 around the pivot shaft 20 outside the housing body 11, and the sealant 13 disposed farther from the inside of the housing body 11 than the bearing 30 inside the peripheral wall 12 and in the extending direction of the pivot shaft 20, sealing the inside of the housing body 11. The projection 21 is disposed closer to the inside of the housing body 11 than the sealant 13 in the extending direction of the pivot shaft 20. Thus, it is possible to prevent breakage of the drive component that switches the contact mechanism units, such as the cams 61, 62, on and off while sealing the inside of the operating unit 3, so that the practicality of the limit switch 1 can be further improved.
[0050] The pivot shaft 20 is provided with the projection 21 extending outward in the radial direction from the pivot shaft 20, and the bearing 30 is provided with the pivot limiting part 31. This makes it possible to easily access the limit switch 1, which is easy to repair, and has high practicality.
[0051] The protrusion 21 is configured by a separate member from that of the pivot shaft 20, and the pivot shaft 20 has the recess 22 extending in a direction intersecting with the extending direction of the pivot shaft 20 to accommodate and retain the protrusion 21. For example, by using a material with a higher hardness than the pivot shaft 20 to form the protrusion 21, the strength of the protrusion 21 can be increased.
[0052] In the limit switch 1, the operating unit 3 includes: the elastic member 63 that regulates the operating lever 40 from the first movement end position P2 toward the return position P1 via the pivot shaft 20 and the first cam 61, and regulates the operating lever 40 from the second movement end position P3 to the return position P1 via the pivot shaft 20 and the second cam 62; the first cam pivot limiting member 614, 71 that limits the pivoting of the first cam 61 in the first direction A in which the operating lever 40 moves from the return position P1 to the second movement end position P3; and the second cam pivot limiting member 624, 72 that limits the pivoting of the second cam in the second direction B in which the operating lever 40 moves from the return position P1 to the first movement end position P2.The elastic member 63, the swing limiting member of the first cam 614, 71, and the swing limiting member of the second cam 624, 72 can reduce the swing of the operating lever 40 at the return position P1 to immediately stop the operating lever 40 at the return position P1. As a result, it is possible to reach the limit switch 1, which can reduce the variation of the return position P1 of the operating lever 40 and operate accurately.
[0053] Further, the first cam pivot limiting part includes a first contact surface 614 provided at the downstream side end of the first transmitter 611 in the second direction B in which the operating lever 40 moves from the return position P1 toward the first movement end position P2, and the first contact projection 71 connected to the housing body 11 and contacting the first contact surface 614 when the operating lever 40 is in the return position P1 to limit the pivoting of the first cam 61 in the first direction A.The second cam swing limiting part includes a second contact surface 624 provided at the downstream side end of the second transmitter 621 in the first direction A, and the second contact protrusion 72 connected to the housing body 11 and contacting the second contact surface 624 when the operating lever 40 is in the return position P1 to limit the swing of the second cam 62 in the second direction B. This makes it possible to further reduce the swing of the operating lever 40 at the return position P1.
[0054] Note that the limit switch 1 is not limited to the above embodiment, but any configuration can be used as long as the operating unit 3 includes the pivot shaft support 50. For example, the projection 21 of the pivot shaft 20, the pivot limiting part 31 of the bearing 30, and the pivot shaft support 50 may be omitted.
[0055] The pivot shaft support 50 is not limited to being configured by the substantially annular second bearing 51 disposed over the circumference of the pivot shaft 20. For example, as shown in Fig. 9, the pivot shaft support 50 may be configured by a protrusion 53 extending outward in the radial direction from the pivot shaft 20. As an example, a plurality of protrusions 53 are provided and arranged at intervals in the circumferential direction of the pivot shaft 20. As described above, any configuration can be adopted in the pivot shaft support 50 as long as it is a configuration in which the pivot shaft support 50 can allow the pivot shaft 20 to pivot in a state where the external force F along the extending direction of the pivot shaft 20 is not applied to the operation lever 40, and the pivot shaft support 50 can contact the peripheral wall 12 to support the pivot shaft 20 in a state where the external force F along the extending direction of the pivot shaft 20 is applied to the operation lever 40.This means that it is possible to achieve limit switch 1, which is less likely to fail and has high design flexibility.
[0056] The projection is not limited to the pivot shaft 20, but for example, as shown in Fig. 10, the projection may be a projection 34 extending in a direction perpendicular to the pivot shaft 20 from the inner peripheral surface of the bearing 30 facing the pivot shaft 20. The pivot shaft 20 in Fig. 10 is provided with a groove-shaped pivot limiting part 24 which can accommodate the projection 34 of the bearing 30 and extends in the circumferential direction of the pivot shaft 20.
[0057] The projection 21 is not limited to being configured by a separate member from that of the pivot shaft 20, but may be integrally configured by the same member as that of the pivot shaft 20.
[0058] In an embodiment of the invention, the pivot limiting part of the first cam and the pivot limiting part of the second cam are not limited to being configured by the contact surfaces 614, 624 and the contact protrusions 71, 72. For example, as shown in FIG. 4, the pivot limiting part of the first cam may be configured by a third contact surface 616 and a first elastic stopper 73, and the pivot limiting part of the second cam may be configured by a fourth contact surface 626 and a second elastic stopper 74. The third contact surface 616 and the fourth contact surface 626 are respectively arranged between the first transmitter 611 and the second transmitter 621 to provide a contact surface for the housing body 11 in the extending direction of the operating lever 40 (i.e., in Fig.11 upwards) as viewed from the extending direction of the pivot shaft 20 when the pivot shaft 20 is in the return position P1. The first elastic stopper 73 and the second elastic stopper 74 contact the third contact surface 616 and the fourth contact surface 626, respectively, and excite the respective cams 61, 62 in a direction perpendicular to the pivot shaft 20.
[0059] For example, each of the first contact protrusion 71 and the second contact protrusion 72 may be configured by the same member as that of the housing body 11, or may be configured by a separate member (e.g., an elastic member such as rubber, a set of screws, or washers) separated from the housing body 11.
[0060] As described above, any configuration can be adopted in each of the swing limiting part of the first cam and the swing limiting part of the second cam, as long as it is a configuration in which the swing of the first cam 61 in the second direction B or the swing of the second cam 62 in the first direction A can be restricted. That is, it is possible to achieve the limit switch 1 that can be operated accurately and has high design flexibility.
[0061] The peripheral wall 12 is not limited to being provided integrally with the housing 10, but may be provided separately. In this case, the peripheral wall 12 may be made of the same material as the housing body 11 or a different material therefrom. INDUSTRIAL APPLICABILITY
[0062] The limit switch of the present disclosure can be applied, for example, to a production line of an automobile or the like. DESCRIPTION OF REFERENCE SYMBOLS 1 limit switch 2 switch bodies 3 operating unit 10 housings 11 Housing body 12 Perimeter wall 121 inner peripheral surface 13 Sealant 20 Swivel shaft 21 lead 22 recess 23 Locking surface 24 Swivel limiting part 30 warehouses 31 Swivel limiting part 32 first end 33 second end 34 lead 40 operating levers 41 roll 50 swivel shaft support 51 second camp 52 End 53 lead 61 first cam 611 first transformer 612 through hole 613 locking projection 614 first contact surface 615 spring locking part 616 third contact surface 62 second cam 621 second transformer 622 through hole 623 locking projection 624 second contact surface 625 spring locking part 626 fourth contact surface 63 elastic part 631 first end 632 second end 71 first contact lead 72 second contact lead 73 first elastic stop 74 second elastic stop P1 Return position P2 first movement end position P3 second movement end position A first direction B second direction L Swivel axis
Claims
[1] Limit switch (1), comprising: a switch body (2) with a contact mechanism inside; and an operating unit (3) connected to the switch body (2), wherein the operating unit (3) comprises a housing (10) connected to the switch body (2), a pivot shaft (20) extending from an outer side of the housing (10) to an inner side of the housing (10) and pivotable about an extension direction of the pivot shaft (20); a bearing (30) provided in the housing (10) and pivotally supporting the pivot shaft (20), an operating lever (40) which is connected to the pivot shaft (20) outside the housing (10) and is pivotable together with the pivot shaft (20) between an intermediate return position (P1) and a first end-of-movement position (P2) and a second end-of-movement position (P3), wherein the intermediate return position (P1) and the two end-of-movement positions (P2, P3) are arranged at intervals in a circumferential direction with respect to the direction of extension of the pivot shaft (20), an annular first cam (61) connected to the pivot shaft (20) within the housing (10) and comprising a first transmitter (611) which pivots together with the pivot shaft (20) to switch the contact mechanism on or off when the operating lever (40) pivots from the intermediate return position (P1) to the first end position (P2), wherein the first transmitter (611) does not pivot together with the pivot shaft (20) when the operating lever (40) pivots from the intermediate return position (P1) to the second end position (P3), wherein the first cam (61) allows the pivoting of the pivot shaft (20) when the first transmitter (611) does not pivot, an annular second cam (62) connected to the pivot shaft (20) with a gap from the first cam (61) in the extending direction of the pivot shaft (20) and arranged symmetrically with the first cam (61) with respect to the pivot shaft (20) within the housing (10), and comprising a second transmitter (621) which pivots together with the pivot shaft (20) to switch the contact mechanism on or off when the operating lever (40) pivots from the intermediate return position (P1) to the second movement end position (P3), wherein the second transmitter (621) does not pivot together with the pivot shaft (20) when the operating lever (40) pivots from the intermediate return position (P1) to the first movement end position (P2), wherein the second cam (62) allows the pivoting of the pivot shaft (20) when the second transmitter (621) does not swings, an elastic member (63) provided within the housing (10) drives the operating lever (40) from the first movement end position (P2) toward the intermediate return position (P1) via the pivot shaft (20) and the first cam (61), and drives the operating lever (40) from the second movement end position (P3) toward the intermediate return position (P1) via the pivot shaft (20) and the second cam (62), a pivot limiting part (614, 73) of the first cam (61) provided within the housing (10) and limiting the pivoting of the first cam (61) in a first direction (A) in which the operating lever (40) moves from the intermediate return position (P1) to the second movement end position (P3), and a pivot limiting part (624, 74) of the second cam (62) provided within the housing (10) and limiting the pivoting of the second cam (62) in a second direction (B) in which the operating lever (40) moves from the intermediate return position (P1) to the first movement end position (P2), characterized by , that the pivot limiting part (614, 73) of the first cam (61) comprises a first elastic stopper (73) which cooperates with the first cam (61) in a direction perpendicular to the pivot shaft (20) in a state in which the operating lever (40) is in the intermediate return position (P1) to limit the pivoting of the first cam (61) in the first direction (A), and the pivot limiting part (624, 74) of the second cam (62) comprises a second elastic stopper (74) cooperating with the second cam (62) in a direction perpendicular to the pivot shaft (20) in a state where the operating lever (40) is in the intermediate return position (P1) to limit the pivoting of the second cam (62) in the second direction (B). [2] Limit switch (1) according to claim 1, characterized by in that the pivot shaft (20) to which the first cam (61), the second cam (62) and the elastic member (63) are connected has a substantially semi-arc shape in cross-section along the direction perpendicular to the extension direction of the pivot shaft (20) and is formed with a locking surface (23) on which locking projections (613, 623) of the first cam (61) and the second cam (62) are locked. [3] Limit switch (1) according to claim 1 or 2, characterized by , that on a first contact surface (614) of the first transmitter (611) with respect to the pivot shaft (20) a spring locking part (615) for locking a first end (631) of the elastic part (63) is provided and that on a second contact surface (624) of the second transmitter (621) with respect to the pivot shaft (20) a spring locking part (625) for locking a second end (632) of the elastic part (63) is provided.
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