The present invention relates to a manufacture method of a concave disc-shaped structure of bimetal strip, particularly to one that has a displaceable positioning hole located on the inner edge arranged on two guiding pins, and the guiding surface is used to condense during pressing down so that the assembling hole at the outer edge can be inserted into the rivet to be riveted and combined for positioning.
The conventional push button switch with light for general indoor use, which is a see saw switch, when either end of the block is pressed, the bump at the bottom end pushes a spring sheet to contact the see saw to form a on or off state; however, it is found that this structure is a passive switch structure. Each change of the on or off state must cooperate with a pressing action, otherwise the on state is still on, so there is no function of automatic switching, and when the switch is in the on state and the power is overload, because it does not have the automatic trip function, it is very easy to cause the short circuit; therefore, there is a safety risk in use.
The bimetal strip is a composite material composed of two or more metals or other materials with suitable properties, bimetal strip is also known as thermal bimetal strip, two strips have two different expand rates. when they are heated, the different expansions force the flat strip to bend one way.
In the earlier prior art, it is disclosed that the contact spring leaf composed of bimetal strip will trip when the temperature rises to the trip temperature (generally set to 100° C.-150° C.) when overloaded, to avoid short circuit. Such structure can be found in Taiwan patent applications No. 398674.
Referring to
The alloy plate 7 is attached to the bending portion 51 of the second conductive plate 5 and the positioning hole 73. The alloy plate 7 is made from a thin metal sheet and the contacting plate 72 disposed centrally is provided with a slit T2 in both side and tail portions. When the alloy plate 7 is shrunk to the narrower width W2 at its positioning end, a curvature will be naturally formed by its internal stress. Accordingly, the curvature can be formed naturally instead of forming a convex contacting plate with conventional pressing process. Since no mechanic force is applied to the alloy plate 7, no internal stress is constrained within the alloy plate, accordingly, the deforming curvature resulted from temperature rising as electric current flows through it will be remained unchanged. On the other hand, the ratio between the width W1 of free end and the width W2 of positioning end can be specially arranged such that the alloy plate 7 can be provided with bi-directional switching functions, as shown in
However, when narrowing the positioning end of the alloy plate 7 smaller than width W2, the method is to stamp two symmetrical notches 76 on both sides of the positioning end in advance, and then use a tool 77 to push inward from the notches 76 on both sides of the positioning end, with the notch 76 located on the outer edge of the alloy plate 7 for inward movement, the notch 76 is aligned with the guide blade seat and pushed inwardly when pressed parallel, so that the positioning hole 73 at the inner edge enters the rivet column 78 for riveting and positioning, and then the positioning hole 73 of the positioning end of the disc-shaped alloy plate 7 is condensed and fixed on the bending body 51 of the second lug 5, and a convex extension control piece 75 on the free end is used as a control for on/off switching action; However, this kind of compression combination method with the tool 77 pushing inward from the notches 76 on both sides of the positioning end and the convex extension control piece 75 have the following defects:
A primary object of the present invention is to provide a manufacture method of a concave disc-shaped structure of bimetal strip that does not damage its internal stress structure, can increase the service life, and can accurately calculate the amperage of the overload current by using the formula V=IR and W=VA to reduce the product defect rate and facilitate the calculation and analysis of the overload trip current.
To achieve the objects mentioned above, the present invention comprises: a). providing a bimetal strip, after stamping the bimetal strip has a positioning end, a free end corresponding to the positioning end, and a connecting lever extending inward from the free end, at the end of the connecting lever has a through hole, and the through hole has a connecting point, and an appropriate gap is cut at the center of the positioning end, and two symmetrical positioning holes are provided at the positioning ends on both sides of the gap, and two symmetrical assembling hole are provided outside the symmetrical positioning holes, and the center distance of the two symmetric positioning holes is D1, and the center distance of the two symmetric assembling holes is D2; b). providing a lug, after stamping the lug has a connecting pin, a combining surface connecting to the connecting pin, the combining surface has a connecting hole for penetration, and the outside of the connecting hole has two symmetrical rivets, define the width of the left and right sides of the connecting hole as W3, the center distance of the two symmetrical rivets is D4, and the D4 is smaller than D2; c). providing an assembling jig, the assembling jig includes a base seat, a first guiding pin and a second guiding pin parallelly arranged on the base seat, the center distance of the first guiding pin and the second guiding pin is D3, the width of the two outer edges of the first guiding pin and the second guiding pin is smaller than the width W3 of the connecting hole, and the base seat is provided with two protruding columns below the two symmetrical rivets of the lug, the protruding columns is used for positioning the bottom edge of the rivets and bearing the punching of the guiding hole of punch, so that the bimetal strip and the lug are smoothly riveted and combined; d). Sleeve the connecting hole of the lug into the first guiding pin and the second guiding pin, and make the bottom of the combining surface against the surface of the base seat; e). Sleeve the positioning hole of the bimetal strip into the first guiding pin and the second guiding pin from the top, making the bimetal strip arrange above the first guiding pin and the second guiding pin; f). providing a compression module, arranged above the first guiding pin and the second guiding pin, the axial direction is provided with a shaft hole for the first guiding pin and the second guiding pin to extend, and two guiding hole of punch arranged on the outside of the two shaft holes, the compression module is sleeved into the first guiding pin and the second guiding pin from top to bottom, and then the bimetal strip is pressed down to make the two symmetrical positioning holes gradually turn inward to condense to the combining surface of the lug, further narrow the center distance D1 of the positioning holes of the bimetal strip to be equidistant from the center distance D3 of the first guiding pin and the second guiding pin, and narrow the center distance D2 of the two symmetrical assembling hole to D4 which is the same as the center distance of the two symmetrical rivets, and sleeve into the two symmetrical rivets, and use the two guiding holes of punch of the compression module, punch the riveting to deform it, and then riveting and bonding the bimetal strip and the lug; g). Raise the compression module, and the bimetal strip and the lug are removed upward from the assembling jig; and h). Form a concave disc-shaped structure of bimetal strip.
Also, the first guiding pin has a peak, and has a guiding surface inclined from top to bottom to inward from the peak.
Also, the second guiding pin has a peak, and has a guiding surface inclined from top to bottom to inward from the peak.
Also, the connecting hole on the lug includes two symmetrical rectangular holes, the distance W3 between the left and right sides of the rectangular holes is greater than the outer edges of the first guiding pin and the second guiding pin, so that the first guiding pin and the second guiding pin can respectively extend through the two rectangular holes.
Also, the connecting hole on the lug includes a long hole, the distance W3 between the left and right sides of the long hole is greater than the outer edges of the first guiding pin and the second guiding pin, so that the first guiding pin and the second guiding pin can respectively extend through the long hole.
With the features disclosed above, the prior art has the notch 76 located on the outer edge of the alloy plate 7 for inward movement, the notch 76 is aligned with the guide blade seat and pushed inwardly when pressed parallel, so that the positioning hole 73 at the inner edge enters the rivet column 78 for riveting and positioning. The present invention is different that having a displaceable positioning hole located on the inner edge arranged on two guiding pins, and the guiding surface is used to condense during pressing down so that the assembling hole at the outer edge can be inserted into the rivet to be riveted and combined for positioning.
With the features disclosed above, the present invention has below features:
Referring to
As
In this embodiment, the guiding surfaces 322/332 inclined from top to bottom to inward from the peak 321/331, making the symmetrical positioning holes 14 of the bimetal strip 10 close inward. Moreover, in this embodiment, the first guiding pin 32 and the second guiding pin 33 have same heights, but not limit to this application. In other words, the first guiding pin 32 and the second guiding pin 33 can have different heights, and the positioning hole 14 can be condensed and assembled by using the height difference.
Finally,
With the feature disclosed above, after the bimetal strip 10 and the lug 20 are combined and positioned by the above method, then an overload switch is formed in the case (not showing in the drawing). However, the overload switch is a conventional art, so the detail need not to be mentioned.
The main difference is the assembling method of the bimetal strip 10 and the lug 20, the difference between the present invention and the prior art is shown in the following table:
With the above mentioned features, the present invention has below benefits:
Although particular embodiments of the invention have been described in detail for purposes of illustration, various modifications and enhancements may be made without departing from the spirit and scope of the invention. Accordingly, the invention is not limited except as by the appended claims.
Number | Date | Country | Kind |
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109137604 | Oct 2020 | TW | national |
Number | Name | Date | Kind |
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7248140 | Yu | Jul 2007 | B2 |
20170148601 | Wang | May 2017 | A1 |
20220139652 | Wang | May 2022 | A1 |
Number | Date | Country | |
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20220139652 A1 | May 2022 | US |