switch

Abstract

Securely fasten one end of the bellows packing within the limited space. [Solution] The cap 14A is fixed to the end of the plunger 13A that is exposed to the outside of the case 12. The bellows packing 15 covers the side of the plunger 13A that is exposed to the outside of the case 12. The cap 14A has a plate-shaped portion 41 that is positioned substantially perpendicular to the ±Y direction and a cylindrical portion 42 that extends from the plate-shaped portion 41 substantially parallel to the ±Y direction and toward the case 12. The plunger 13A has a flange portion 31 on its side. The plunger 13A and the cap 14A have a retaining structure 16 that engages with each other to fix the cap 14A to the plunger 13A, thereby holding the end 51 of the bellows packing 15 between the flange portion 31 of the plunger 13A and the cylindrical portion 42 of the cap 14A.

Description

Technical Field

[0001] This invention relates to a switch.

Background Art

[0002] Patent Documents 1 and 2 disclose a trigger switch.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0004] The trigger switch for a power tool in Patent Document 1 operates a switching mechanism provided in an internal space formed by a case and a cover by operating a trigger. The operating operation from the trigger is transmitted to the switching mechanism by the sliding of a plunger connected to the switching mechanism through a plunger opening. In order to prevent water and dust from entering through the gap between the plunger and the plunger opening, an external packing is provided. The tip of the external packing is engaged with a packing engaging portion provided on the trigger. The switch for a power tool includes not only a trigger type as described in Patent Document 1 and Patent Document 2 but also a plunger type. Since the operating portion of the plunger type switch is smaller and has shape restrictions compared to the trigger type, it is difficult to ensure the adhesion between the external packing and the plunger. An object of this invention is to solve such problems, for example.

Means for Solving the Problems

[0005] The switch comprises a hollow case with a through-hole extending through its side, a plunger inserted through the through-hole and slidable in the axial direction, a cap fixed to the end of the plunger exposed to the outside of the case, and a bellows packing covering the side of the plunger exposed to the outside of the case. The cap has a plate-shaped portion positioned substantially perpendicular to the axial direction and a cylindrical portion extending from the plate-shaped portion substantially parallel to the axial direction and toward the case. The plunger has a flange on its side. The plunger and the cap have a retaining structure that engages with each other to fix the cap to the plunger, thereby holding one end of the bellows packing between the flange of the plunger and the cylindrical portion of the cap. [Effects of the Invention]

[0006] The plunger and cap have a retaining structure, which holds one end of the bellows packing between the flange of the plunger and the cylindrical part of the cap, thus ensuring that one end of the bellows packing is securely fixed within a limited space. [Brief explanation of the drawing]

[0007] [Figure 1] A front view showing an example of a switch. [Figure 2] A side view showing the aforementioned switch. [Figure 3] A partially enlarged cross-sectional view III-III showing the aforementioned switch. [Figure 4] A partially enlarged cross-sectional view IV-IV showing the aforementioned switch. [Figure 5] A partially enlarged perspective view showing an example of a plunger. [Figure 6] A partially enlarged section III-III showing another example of a switch. [Figure 7] A partially enlarged cross-sectional view IV-IV showing the aforementioned switch. [Figure 8] A partially enlarged perspective view showing the plunger of the aforementioned switch. [Modes for carrying out the invention]

[0008] Refer to Figures 1-5 to explain switch 10A. Switch 10A is a plunger-type switch used in applications such as power tools and gardening tools, and requires high water and dust resistance. The switch 10A includes, for example, a case 12, a plunger 13A, a cap 14A, and a bellows packing 15.

[0009] Case 12 is formed, for example, by combining a case body 21 and a cover 22, and has a space inside for housing a switching mechanism (not shown). Case 12 has a through hole 23 on its side (the -Y side), through which the plunger 13A is inserted.

[0010] The plunger 13A is slidable in the axial direction (±Y direction) and transmits external operation to the switching mechanism. For example, the plunger 13A is biased in the -Y direction by a biasing member such as a coil spring, and by pushing it in the +Y direction against this biasing force, it slides in the +Y direction, and when the pushing is stopped, it slides in the -Y direction due to the biasing force of the biasing member and returns to its original position. The plunger 13A has, for example, a flange portion 31, a pair of tip portions 32a and 32b, a cylindrical portion 34, and an annular projection 35. The cylindrical portion 34 is cylindrical in shape and extends in the axial direction (±Y direction). The cylindrical portion 34 has an axial breathing hole 341 that extends in the axial direction (±Y direction) along the central axis, and a radial breathing hole 342 that penetrates the cylindrical portion 34 in a direction substantially perpendicular to the axial direction (±Y direction) and connects the axial breathing hole 341 to the outside of the cylindrical portion 34. This connects the internal space of the case 12 to the outside, preventing a pressure difference from occurring between the internal space and the outside of the case 12 when the plunger 13A is moved, which would reduce the waterproof and dustproof performance. The annular projection 35 is provided near the -Y end of the cylindrical portion 34 and protrudes 360 degrees around the entire circumference of the cylindrical portion 34 in a radially outward direction (+R direction) substantially perpendicular to the axial direction (±Y direction). The flange portion 31 is provided on the +Y side of the annular projection 35 of the cylindrical portion 34 and is flange-shaped, projecting radially outward (+R direction) substantially perpendicular to the axial direction (±Y direction) from the side surface of the cylindrical portion 34. The tip portions 32a and 32b protrude further in the -Y direction from the -Y end of the cylindrical portion 34. The tip portions 32a and 32b are positioned opposite each other with a U-shaped groove 33 in between. For example, tip portion 32a is positioned on the +Z side, and tip portion 32b is positioned on the -Z side. The tip portion 32a is provided with a retaining structure 16, which is a hook portion 36a that protrudes from the outer side surface, for example, in the +Z direction. The hook portion 36a has a surface on the tip side (-Y side) that is inclined at an angle, and a surface on the root side (+Y side) (root side surface 361) that is a plane approximately perpendicular to the axial direction (±Y direction). Similarly, the tip portion 32b is provided with a retaining structure 16, which is a hook portion 36b that protrudes from the outer side surface in the opposite direction to the tip portion 32a, for example in the -Z direction. The hook portion 36b has a surface that is obliquely inclined on the tip side (-Y side), and the surface on the root side (+Y side) (root side surface 361) is a plane that is substantially perpendicular to the axial direction (±Y direction).

[0011] The cap 14A is fixed to the -Y end of the plunger 13A, which is exposed to the outside of the case 12, and covers the end of the plunger 13A. The cap 14A has, for example, a plate-shaped portion 41, a cylindrical portion 42, and an annular groove 45. The plate-like portion 41 is arranged in a circular disc shape, for example, substantially perpendicular to the axial direction (±Y direction). The plate-like portion 41 is provided with a convex portion 47 that protrudes in the +Y direction from the surface on the root side (+Y side). The convex portion 47 extends, for example, in the ±X direction, corresponding to the groove 33 of the plunger 13A, and engages with the groove 33. The cylindrical portion 42 is a substantially cylindrical shape extending in the root direction (+Y direction) from the plate-like portion 41. The inner diameter of the cylindrical portion 42 is slightly smaller than the distance from the +Z side end of the engaging portion 36a to the -Z side end of the engaging portion 36b, and is slightly larger than the width in the ±Z direction of the entire tip portions 32a and 32b excluding the engaging portions 36a and 36b. In the cylindrical portion 42, as an anti-loosening structure 16, a pair of engaging through holes 46a and 46b provided at positions facing each other are provided. The engaging through holes 46a and 46b penetrate in a radial direction substantially perpendicular to the axial direction (±Y direction) of the cylindrical portion 42. The inner surface 461 on the root side (+Y side) of the engaging through hole 46a is a plane substantially perpendicular to the axial direction (±Y direction). Similarly, the inner surface 461 on the root side (+Y side) of the engaging through hole 46b is a plane substantially perpendicular to the axial direction (±Y direction). Since the engaging through holes 46a and 46b penetrate, even when the cap 14A is manufactured using a mold, such a right-angled shape can be provided. The annular groove 45 is recessed over the entire 360-degree circumference in a radial direction (+R direction) substantially perpendicular to the axial direction (±Y direction) from the inner surface of the cylindrical portion 42. The annular groove 45 is provided at a position corresponding to the annular projection 35 and engages with the annular projection 35.

[0012] The bellows packing 15 covers the side surface of the plunger 13A exposed outside the case 12. The end portion 52 on the root side (+Y side) of the bellows packing 15 is closely fixed by fitting to the case 12 around the through hole 23. The end portion 51 on the tip side (-Y side) of the bellows packing 15 is sandwiched between the flange portion 31 and the cylindrical portion 42 around the cylindrical portion 34 and is closely fixed to the plunger 13A. Thereby, it prevents water and dust from entering the case 12 from the gap between the case 12 and the plunger 13A of the through hole 23. [[ID=IO]]

[0013] In the assembly process of the switch 10A, the plunger 13A is inserted into the bellows packing 15, and then the cap l4A is fitted to the plunger 13A, whereby the end portion 51 of the bellows packing 15 is sandwiched between the flange portion 31 of the plunger 13A and the cylindrical portion 42 of the cap 14A. Here, since the distance from the +Z-side end of the engaging portion 36a to the -Z-side end of the engaging portion 36b is larger than the inner diameter of the cylindrical portion 42, when attempting to fit the cap 14A onto the plunger 13A, the cylindrical portion 42 abuts against the obliquely inclined surfaces on the tip side (-Y side) of the engaging portions 36a and 36b. When the cap 14A is further pushed in the +Y direction, the tip portions 32a and 32b bend inward, causing the distance from the +Z-side end of the engaging portion 36a to the -Z-side end of the engaging portion 36b to become smaller. Then, as the cap 14A advances in the +Y direction, the tip portions 32a and 32b return to their original positions, and the engaging portions 36a and 36b engage with the engaging through-holes 46a and 46b. At the same time, the convex portion 47 engages with the groove 33 between the tip portions 32a and 32b, and the cap 14A is fixed to the plunger 13A.

[0014] Since the base side surfaces 361 of the engaging portions 36a and 36b and the inner surfaces 461 of the engaging through-holes 46a and 46b are substantially perpendicular to the axial direction, even if the cap 14A is pulled in the -Y direction, it is possible to prevent the cap 14A from coming off the plunger 13A. Also, since the convex portion 47 engages with the groove 33 between the tip portions 32a and 32b, it is possible to prevent the distance between the tip portions 32a and 32b from becoming smaller, thereby preventing the cap 14A from coming off the plunger 13A.

[0015] In this way, by fixing the cap 14A to the plunger 13A, the end portion 51 of the bellows packing 15 is sandwiched between the cylindrical portion 42 of the cap 14A and the flange portion 31 of the plunger 13A, and is fixed in close contact with the plunger 13A, enabling the end portion 51 of the bellows packing 15 to be securely fixed within the limited space.

[0016] Furthermore, an annular rib protruding in the direction of the root (+Y direction) may be provided on the end face of the base side (+Y side) of the cylindrical portion 42. The annular rib may, for example, have a triangular cross-section and be provided around the entire circumference of 360 degrees. As a result, when the cap 14A is fixed to the plunger 13A, the annular rib bites into the end 51 of the bellows packing 15, causing the cap 14A and the bellows packing 15 to be in close contact, thereby improving waterproofing and dustproofing. Furthermore, a thin concave groove extending radially downward (-Z direction) may be provided on the base side (+Y side) end face of the cylindrical portion 42. When the cap 14A and the plunger 13A are in close contact, the inside and outside of the cylindrical portion 42 communicate through this concave groove, thereby ensuring communication between the internal space of the case 12 and the outside via the axial breathing hole 341 and the radial breathing hole 342. The concave groove may be stepped in shape, with the outer side being thinner than the inner side. A cylindrical sponge packing may be provided inside the axial breathing hole 341. By pushing a sponge packing with a larger diameter than the axial breathing hole 341 into the axial breathing hole 341, the amount of air passing through the axial breathing hole 341 can be adjusted, improving waterproofing and dustproofing. A square-shaped through-hole may be provided in the cover 22, and adhesive may be filled through this through-hole. This fills the gaps in the component mating area, improving waterproofing and dustproofing, and also seals the soldered parts of the PCB connector terminals to prevent short circuits caused by moisture and dust.

[0017] Refer to Figures 6-8 to explain switch 10B. Switch 10B is almost identical to switch 10A, but instead of plunger 13A and cap 14A, it has plunger 13B and cap 14B.

[0018] Plunger 13B is almost identical to plunger 13A, but has a tip portion 32c instead of tip portions 32a and 32b. The tip portion 32c protrudes further in the -Y direction from the -Y end of the cylindrical portion 34. The tip portion 32c is, for example, a roughly cylindrical shape coaxial with the cylindrical portion 34. The tip portion 32c is provided with a groove portion 38 recessed on its side surface as a retaining structure 18. The groove portion 38 has an axial groove 381 extending along the axial direction (±Y direction) and a circumferential groove 382 extending along the circumferential direction (±C direction) which is substantially perpendicular to the axial direction (±Y direction). The axial groove 381 is provided, for example, at a position in the +X direction when viewed from the central axis of the plunger 13B, and its tip end (-Y side) reaches the tip end face (-Y side) of the tip portion 32c and is open. The circumferential groove 382 has an L-shape, with its end in the clockwise direction (+C direction) when viewed from the tip side (-Y side) connecting to the end of the axial groove 381 on the root side (+Y side). From this connection, it extends counterclockwise (-C direction) for approximately 90 degrees, reaching, for example, a position in the +Z direction when viewed from the central axis of the plunger 13B. The circumferential groove 382 is provided with groove engagement portions 383 and 384. The groove engagement portion 383 protrudes from the inner surface on the root side (+Y side) of the circumferential groove 382 toward the tip side (-Y direction). The groove engagement portion 384 protrudes from the inner surface on the tip side (-Y side) of the circumferential groove 382 toward the root side (+Y direction).

[0019] Cap 14B is almost identical to cap 14A, but instead of engagement through holes 46a and 46b, it has a retaining structure 18 consisting of a protrusion 48 and a retaining through hole 49. The protrusion 48 projects radially inward (-R direction) from the inner surface of the cylindrical portion 42, substantially perpendicular to the axial direction (±Y direction). The protrusion 48 engages with the groove 38 of the plunger 13B. The width of the protrusion 48 in the axial direction (±Y direction) is slightly smaller than the width of the circumferential groove 382 in the axial direction (±Y direction), and slightly larger than the distance between the groove engagement portions 383 and 384 in the axial direction (±Y direction). The retaining through-hole 49 penetrates the cylindrical portion 42 in a radial direction (±R direction) substantially perpendicular to the axial direction (±Y direction). The retaining through-hole 49 is positioned opposite the protrusion 48. As a result, when the cap 14B is fixed to the plunger 13B, the retaining through-hole 49 is positioned in the -Z direction when viewed from the central axis of the plunger 13B.

[0020] The +R side surface of the protrusion 48 is a plane substantially parallel to the direction in which the protrusion 48 protrudes. Since the protrusion 48 protrudes in a direction substantially perpendicular to the axial direction (±Y direction) (-R direction), the +R side surface of the protrusion 48 is substantially parallel to the axial direction (±Y direction). Since the retaining through hole 49 is provided at a position opposite the protrusion 48, such a right-angle shape can be provided even when manufacturing the cap 14B using a mold.

[0021] The +R side surfaces of the groove engagement portions 383 and 384 are inclined at an angle so that the protrusions 48 can overcome the groove engagement portions 383 and 384 and reach the innermost part (-C side end) of the circumferential groove 382. The -R side surfaces (inner sides 385 and 386) of the groove engagement portions 383 and 384 are planes substantially parallel to the axial direction (±Y direction) so as to prevent the protrusion 48 from returning in the +C direction when it reaches the innermost part of the circumferential groove 382 (the -C end).

[0022] In the assembly process of the switch 10B, the plunger 13B is inserted into the bellows packing 15, and then the cap 14B is fitted onto the plunger 13B, thereby sandwiching the end 51 of the bellows packing 15 between the flange 31 of the plunger 13B and the cylindrical part 42 of the cap 14B. First, the protrusion 48 of the cap 14B is aligned with the axial groove 381 of the plunger 13B, and the cap 14B is moved in the +Y direction to engage the protrusion 48 with the axial groove 381. Once the protrusion 48 reaches the innermost part (the +Y side end) where the axial groove 381 connects with the circumferential groove 382, ​​the cap 14B is then rotated in the -C direction. When the protrusion 48 comes into contact with the groove engagement parts 383 and 384, resistance is generated. However, when the cap 14B is further rotated in the -C direction, the protrusion 48 and the groove engagement parts 383 and 384 undergo elastic deformation, causing the protrusion 48 to overcome the groove engagement parts 383 and 384 and reach the innermost part (the -C side end) of the circumferential groove 382.

[0023] Since the protrusion 48 engages with the innermost part (the -C side end) of the circumferential groove 382, ​​even if the cap 14B is pulled in the -Y direction, it is possible to prevent the cap 14B from coming off the plunger 13B. Furthermore, since the inner surfaces 385 and 386 of the grooved gripping portions 383 and 384, and the +R side surface of the protrusion 48 are substantially parallel to the axial direction, even if the cap 14B is about to rotate in the +R direction, the protrusion 48 prevents it from going over the grooved gripping portions 383 and 384, thereby preventing the cap 14B from rotating and coming off the plunger 13B.

[0024] In this way, the cap 14B is fixed to the plunger 13B, so that the end 51 of the bellows packing 15 is sandwiched between the cylindrical portion 42 of the cap 14B and the flange portion 31 of the plunger 13B, and is fixed in close contact with the plunger 13B, and the end 51 of the bellows packing 15 can be securely fixed within a limited space.

[0025] The embodiments described above are examples intended to facilitate understanding of the present invention. The present invention is not limited thereto and includes various modifications, changes, additions, or deletions without departing from the scope defined by the appended claims. This will be readily apparent to those skilled in the art from the above description.

[0026] Switches for power tools and gardening tools are predominantly waterproof. The plunger type, which uses the same switch mechanism as a trigger switch but differs only in the shape of the operating part, is used in a wide variety of power tools and gardening tools. Its axial operating part allows for indirect operation via an operating part on the tool itself. The operating part is small and has shape constraints. Plunger-type switches require the same ease of assembly and performance (waterproofing, mechanical durability) as trigger-type switches. Trigger-type valves use a pin to prevent the bellows packing from coming loose, ensuring a tight seal between the packing and the plunger, but plunger-type valves lack the space for this. Using fastening components instead of pins reduces space, making assembly more difficult. Therefore, it is necessary to maintain airtightness between the bellows packing and the plunger without using fixing parts. Therefore, the position-retaining shape is provided at 360° on the circumference of the axis, creating a structure that separates the outside from the inside using the position-retaining shape. In plunger-type caps, the circular surface of the cap is used for manipulation, making it impossible to create a positioning shape on the circular surface. By providing a second positioning shape in the limited space on the side of the cap, waterproofing is improved. The breathing holes prevent the occurrence of pressure differences. A retaining mechanism is provided to maintain a tight seal between the bellows packing and the plunger. This improves waterproof and dustproof performance, accommodates dimensional constraints, and makes assembly easier with a minimum number of parts.

[0027] This retaining structure is provided on the outer side of a convex shape circumferentially located on the shaft of the plunger, in the space on the side of the cap excluding the circular surface at the tip of the cap, which is the operating surface. To prevent the cap from shifting position due to repeated operation, one of the following shapes is provided: The plunger has two protrusions, and its corners are right-angled. The corners on the cap side that the two protrusions fit into are also right-angled. Due to the mold structure of the cap, a through hole is provided, making the right-angled shape possible. A U-shaped groove is provided between the two protrusions on the plunger. A convex shape is provided on the back side of the cap that fits into the U-shaped groove. Alternatively, the corners of the cylinder inside the cap can be made right-angled. Due to the mold structure of the cap, a through hole can be provided, making a right-angled shape possible. The corners of the plunger groove that fits into the cylinder inside the cap can also be made right-angled. One or two protrusions can be provided on the wall surface of the plunger groove to prevent the cap from returning in the direction of rotation. [Explanation of symbols]

[0028] 10A, 10B Switch, 12 Case, 21 Case body, 22 Cover, 23 Through hole, 13A, 13B Plunger, 31 Flange, 32a, 32b, 32c Tip, 33 Groove, 34 Cylindrical part, 341 Axial breathing hole, 342 Radial breathing hole, 35 Annular projection, 36a, 36b Catching part, 361 Base side, 38 Groove, 381 Axial groove, 382 Circumferential groove, 383, 384 Groove catching part, 385, 386 Inner side, 14A, 14B Cap, 41 Plate-shaped part, 42 Cylindrical part, 45 Annular groove, 46a, 46b Engaging through hole, 461 Inner surface, 47 Convex part, 48 Convex part, 49 Retaining through hole, 15 Bellows packing, 51, 52 ends, 16, 18 retaining structure.

Claims

1. A hollow case with through holes that penetrate the sides, A plunger inserted through the aforementioned through hole and slidable in the axial direction, A cap fixed to the end of the plunger exposed to the outside of the case, A bellows packing covering the side of the plunger exposed to the outside of the case and Equipped with, The aforementioned cap is A plate-shaped portion arranged substantially perpendicular to the aforementioned axial direction, A cylindrical portion extending from the plate-like portion in a direction substantially parallel to the axial direction and approaching the case, It has, The plunger has a flange on its side, The plunger and the cap have a retaining structure that engages with each other to fix the cap to the plunger, thereby holding one end of the bellows packing between the flange portion of the plunger and the cylindrical portion of the cap. switch.

2. The plunger mentioned above is It has a pair of tip portions that are substantially parallel to the axial direction and extend away from the case, and are opposite to each other, The aforementioned retaining structure is The cylindrical portion is provided with a pair of engagement through holes facing each other, A pair of hooks protrudes from the outer sides of the pair of tip portions and engages with the pair of engagement through holes, respectively. It has, The inner surface of the case side of the engagement through hole and the side surface of the case side of the hook are planes substantially perpendicular to the axial direction. The switch according to claim 1.

3. The aforementioned retaining structure is A convex portion that protrudes from the side surface of the case of the plate-shaped portion and engages with the groove between the pair of tip portions to prevent the distance between the pair of tip portions from decreasing. It further has, The switch according to claim 2.

4. The plunger mentioned above is A substantially cylindrical tip portion extending substantially parallel to the axial direction and away from the case It has, The aforementioned retaining structure is The aforementioned tip portion has a recessed groove, A protrusion that extends from the inner surface of the cylindrical portion and engages with the groove, A retaining through hole is provided in the cylindrical portion at a position opposite to the protrusion, It has, The groove portion is An axial groove extending from the tip of the aforementioned tip portion along the axial direction, A circumferential groove extending in a predetermined direction along the circumferential direction of the tip portion from the end of the axial groove, It has, The aforementioned circumferential groove is It has a grooved gripping portion that protrudes from the inner surface, The side of the protrusion opposite to the predetermined direction, and the side of the groove-catching portion on the side in the predetermined direction, are planes substantially parallel to the axial direction. The switch according to claim 1.

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