A manual reset snap-action temperature controller

Abstract

A manual reset snap-action thermostat belongs to the technical field of snap-action thermostats. A first, second, and third through-hole are provided in the center of the base, with the distance between the first and third through-holes equal to the distance between the second and third through-holes. A fourth and fifth through-hole are provided on the front and rear sides of the lower part of the reset handle. The first lower rod and the first upper rod of the first reset rod are movably connected to the first and fourth through-holes, respectively. The second lower rod and the second upper rod of the second reset rod are movably connected to the second and fifth through-holes, respectively. The lower ends of the first and second reset rods are movably connected to a bimetallic disc. This manual reset snap-action thermostat, due to its double reset rod structure, can achieve a service life of 20,000 cycles or more. Because the reset pressure is not applied to the moving spring, it does not deform, thus improving the service life of the moving and stationary contacts. The thermostat body is relatively short, making it suitable for equipment applications with strict installation height requirements.

Description

Technical Field

[0001] This invention relates to the field of snap-action thermostats, and particularly to a manually reset snap-action thermostat. Background Technology

[0002] Manually reset snap-on thermostats are used in equipment that requires over-temperature protection, such as instant electric water heaters and small thick-film instant heating modules.

[0003] The existing manual reset snap-action thermostat is cylindrical, with a body height of approximately 17.5 mm. Along its centerline, from top to bottom, are a reset rod, a moving spring, an actuating rod, and a circular bimetallic disc, all connected in movable contact. During manual reset, the reset pressure acts on the moving spring, which in turn moves the actuating rod downwards, causing the bimetallic disc (center) to flip downwards and reset. This process deforms the moving spring, and prolonged operation can severely affect the closure of its moving and stationary contacts. Furthermore, the center of the circular bimetallic disc is where internal stress is most concentrated; prolonged downward force from the actuating rod can damage and crack this area, leading to failure and reducing the bimetallic disc's lifespan. The existing cylindrical manual reset snap-action thermostat has a lifespan of 10,000 cycles. Summary of the Invention

[0004] The technical problem this invention aims to solve is to provide a manually reset snap-action thermostat, which employs a double reset rod structure. The lower ends of the double reset rods are symmetrically and equidistantly connected to both sides of the center of a circular bimetallic disc. This allows the manually reset snap-action thermostat to achieve a service life of 20,000 cycles or more. Since the moving spring no longer bears the reset pressure, the service life of the moving and stationary contact assembly is significantly improved. Simultaneously, it greatly reduces the height of the thermostat body, meeting the installation location requirements of some equipment.

[0005] The technical solution proposed in this invention is as follows: A manually reset snap-action thermostat includes a cover, a bimetallic disc, a transmission rod, a base, a bottom cover, a moving contact assembly, and a stationary contact assembly. From top to bottom, the bottom cover, moving contact assembly, stationary contact assembly, base, transmission rod, cover, and bimetallic disc are arranged in sequence. The bottom cover is fixedly connected to the base, one end of the moving contact assembly, and one end of the stationary contact assembly via fixing posts and rivets. The outer circumference of the bimetallic disc is placed within an annular flat groove formed between the bottom of the base and the bottom of the cover, and is in movable contact with this annular flat groove. The upper end of the vertically placed transmission rod is in movable contact with the protrusion in the middle of the moving spring of the moving contact assembly, and the lower end of the transmission rod is in movable contact with the circular... The base has a movable contact connection at the center; it also includes a first reset rod, a second reset rod, and a reset handle; the base has a third through hole in the center, and the base has a first through hole and a second through hole equidistant from the third through hole on the front and rear sides of the base; the lower front and rear wings of the reset handle have a fourth through hole and a fifth through hole respectively; the first lower rod of the first reset rod is movably sleeved to the first through hole, and the first upper rod of the first reset rod is movably sleeved to the fourth through hole; the second lower rod of the second reset rod is movably sleeved to the second through hole, and the second upper rod of the second reset rod is movably sleeved to the fifth through hole; the lower ends of the first reset rod and the lower ends of the second reset rod are respectively movably contacted with the bimetallic disc.

[0006] The first reset rod consists of a first lower rod, a first limiting rod, and a first upper rod. The lower plane of the first limiting rod is in movable contact with the base, and the upper plane of the first limiting rod is in movable contact with the lower plane of the front wing of the reset handle. The lower end of the first lower rod is spherical and is in movable contact with the bimetallic disc, with its contact point being A.

[0007] The second reset rod consists of a second lower rod, a second limiting rod, and a second upper rod. The lower plane of the second limiting rod is in movable contact with the base, and the upper plane of the second limiting rod is in movable contact with the lower plane of the rear wing of the reset handle. The lower end of the second lower rod is spherical and is in movable contact with the bimetallic disc, with its contact point being B.

[0008] The center of the bimetallic disc is O, and contact A and contact B are located on the same diameter. = ,straight line The length is 0.55 to 0.65 times the diameter of the bimetallic disc.

[0009] The reset handle is in active contact with the rectangular through hole in the middle of the bottom cover.

[0010] The present invention has the following significant technical effects: (1) The manual reset snap-action thermostat of the present invention adopts a double reset rod structure. Its body is in the shape of a flat rectangular parallelepiped. Its over-temperature protection action structure consists of a moving spring, a transmission rod, and a bimetallic disc arranged sequentially from top to bottom in the center of the body. This structure is basically the same as the existing manual reset snap-action thermostat with a tall cylindrical body. That is, when the action temperature is reached, the bimetallic disc flips upward. The reaction force borne by its center is mainly the elastic force of the moving spring and the weight of the action rod, which is measured to be about 2.8N. When the temperature of the heating element of the equipment drops and manual reset is required, for the existing manual reset snap-action thermostat, the reset pressure is applied to the center of the bimetallic disc through the reset rod and the action rod located on the same center line, causing it to flip downward and reset, which is measured to be about 2.7N. For the manual reset snap-action thermostat of the present invention, the reset pressure is divided into two equal and opposite components that act on points A and B of the bimetallic disc through the first and second reset rods, respectively, which are measured to be about 1.3N. As can be seen, the reset pressure of this manual reset snap-action thermostat is not concentrated at the central point of the bimetallic disc, but is decomposed into two components applied to points A and B on either side of the central point. The distance between points A and B is approximately 3 / 5 of the diameter of the bimetallic disc. This reduces the reset pressure required to flip the bimetallic disc downwards and distributes it to two points, minimizing damage to the disc. Furthermore, the greater distance between points A and B from the center significantly extends the lifespan of the bimetallic disc. This is a major factor contributing to the increased lifespan of this manual reset snap-action thermostat, which can reach 20,000 cycles or more.

[0011] (2) Since the reset handle (bridge-shaped) of this manual reset snap-action thermostat has no direct contact with the moving spring, the reset pressure will not be applied to the moving spring. Therefore, the moving spring will not be deformed as a result, thereby improving the working life of the moving and stationary contacts.

[0012] (3) Since this manual reset snap-action thermostat adopts a double reset rod structure, it can be made into a flat cuboid, so that its body height is reduced from the existing high cylindrical manual reset snap-action thermostat body height of 17.5mm to the body height of this flat cuboid manual reset snap-action thermostat body height of 7.6mm, so as to meet the installation structure requirements of instant electric water heaters, etc. Attached Figure Description

[0013] Figure 1 This is a schematic diagram of a manually reset snap-action temperature controller according to the present invention.

[0014] Figure 2 yes Figure 1 The diagram shows a cross-sectional view of the CC section.

[0015] Figure 3 yes Figure 1The diagram shows a cross-sectional view of DD.

[0016] Figure 4 yes Figure 1 The diagram shows the location and structure of the main components of a manual reset snap-action temperature controller.

[0017] Figure 5 yes Figure 1 The diagram shows the state of a manually reset snap-action temperature controller after an over-temperature action.

[0018] Figure 6 yes Figure 1 The diagram shows the structure of the reset handle.

[0019] The following are the labels in the diagram: 1. Cover; 2. Bimetallic disc; 3. Transmission rod; 4. First reset rod; 4-1. First lower rod; 4-2. First limiting rod; 4-3. First upper rod; 5. Second reset rod; 5-1. Second lower rod; 5-2. Second limiting rod; 5-3. Second upper rod; 6. Base; 6-1. First through hole; 6-2. Second through hole; 6-3. Third through hole; 7. Bottom cover; 8. Moving contact assembly; 8-1. Moving spring; 8-2. Moving contact; 8-3. Second terminal; 9. Reset handle; 9-1. Fourth through hole; 9-2. Fifth through hole; 10. Stationary contact assembly; 10-1. First terminal; 10-2. Stationary contact; 10-3. Conductive sheet; 11. Rivet; 12. Fixing post. Detailed Implementation

[0020] The present invention will be further described in detail through the following embodiments.

[0021] See Figures 1-6As shown, a manual reset snap-action thermostat includes a cover 1, a bimetallic disc 2, a transmission rod 3, a base 6, a bottom cover 7, a moving contact assembly 8, and a stationary contact assembly 10. From top to bottom, the bottom cover 7, moving contact assembly 8, stationary contact assembly 10, base 6, transmission rod 3, cover 1, and bimetallic disc 2 are arranged sequentially. The bottom cover 7 is fixedly connected to the base 6, one end of the moving contact assembly 8, and one end of the stationary contact assembly 10 by fixing posts 12 and rivets 11. The outer periphery of the bimetallic disc 2 is placed within an annular flat groove formed between the bottom of the base 6 and the bottom of the cover 1, and is in movable contact with this annular flat groove. The upper end of the vertically placed transmission rod 3 is in movable contact with the protrusion in the middle of the moving spring 8-1 of the moving contact assembly 8, and the lower end of the transmission rod 3 is in movable contact with the center of the bimetallic disc 2. It also includes a first reset rod 4, a second reset rod 5, and a reset handle 9; the base 6 has a third through hole 6-3 in the center, and the base 6 on both sides of the third through hole 6-3 has a first through hole 6-1 and a second through hole 6-2 equidistant from it; the lower front and rear wings of the reset handle 9 have a fourth through hole 9-1 and a fifth through hole 9-2 respectively; the first lower rod 4-1 of the first reset rod 4 is movably connected to the first through hole 6-1, and the first upper rod 4-3 of the first reset rod 4 is movably connected to the fourth through hole 9-1; the second lower rod 5-1 of the second reset rod 5 is movably connected to the second through hole 6-2, and the second upper rod 5-3 of the second reset rod 5 is movably connected to the fifth through hole 9-2; the lower ends of the first reset rod 4 and the second reset rod 5 are respectively in contact with the bimetallic disc 2.

[0022] The first reset rod 4 is composed of a first lower rod 4-1, a first limiting rod 4-2, and a first upper rod 4-3. The lower plane of the first limiting rod 4-2 is in movable contact with the base 6, and the upper plane of the first limiting rod 4-2 is in movable contact with the lower plane of the front wing of the reset handle 9. The lower end of the first lower rod 4-1 is spherical and is in movable contact with the bimetallic disc 2, with its contact point being A.

[0023] The second reset rod 5 consists of a second lower rod 5-1, a second limiting rod 5-2, and a second upper rod 5-3. The lower plane of the second limiting rod 5-2 is in movable contact with the base 6, and the upper plane of the second limiting rod 5-2 is in movable contact with the lower plane of the rear wing of the reset handle 9. The lower end of the second lower rod 5-1 is spherical and is in movable contact with the bimetallic disc 2, with its contact point being B.

[0024] The center of the bimetallic disc 2 is O, and the contact points A and B are located on the same diameter. = ,straight line The length is 0.55 to 0.65 times the diameter of the bimetallic disc 2.

[0025] The reset handle 9 is in active contact with the rectangular through hole in the middle of the bottom cover 7.

[0026] The stationary contact assembly 10 consists of a stationary contact 10-2, a conductive sheet 10-3, and a first terminal 10-1. The stationary contact 10-2 is welded and fixed to one side of the conductive sheet 10-3, and the other side is welded and fixedly connected to the first terminal 10-1. The moving contact assembly 8 consists of a moving contact 8-2, a moving spring 8-1, and a first terminal 8-3. The moving spring 8-1 has a downward protrusion in the middle, and the moving contact 8-2 is welded and fixed to one side of it, while the other side is welded and fixedly connected to the second terminal 8-3.

[0027] The working principle and process of this manual reset snap-action temperature controller are as follows: In existing manual reset snap-action thermostats, the centerlines of the reset lever, actuating lever, and bimetallic disc all coincide with the thermostat's centerline. When the bimetallic disc needs to be manually flipped back to its original position, all reset pressure is applied directly to the center of the bimetallic disc through the reset lever, moving spring, and actuating lever. The center of the bimetallic disc is where internal stress is most concentrated. Repeatedly applying a large reset pressure to this area over a long period will cause it to crack, break, and fail, significantly reducing its lifespan. This is the primary factor contributing to the thermostat's short lifespan. Furthermore, repeatedly applying large reset pressure directly to the thin moving spring over a long period will cause deformation, resulting in misalignment and poor contact between the moving contact 8-2 and the stationary contact 10-2. This can easily generate sparks, further damaging the moving and stationary contacts and shortening the thermostat's lifespan.

[0028] To overcome the shortcomings of existing manual reset snap-action thermostats and improve their service life, this manual reset snap-action thermostat adopts a double reset rod structure. The reset pressure is decomposed into two equal, vertically downward components, which are applied directly to points A and B, equidistant from the center O of the bimetallic disc 2, via the first reset rod 4 and the second reset rod 5, causing the bimetallic disc 2 to reset and flip downwards. Since the component forces are relatively small, and the force points A and B are where the internal stress of the bimetallic disc 2 is relatively low, the service life of the bimetallic disc is greatly improved, thus significantly increasing the service life of this manual reset snap-action thermostat.

[0029] Furthermore, since the reset pressure does not require the moving spring 8-1 to apply force to the bimetallic disc 2, it will not deform significantly during long-term operation, greatly improving the service life of the moving and stationary contacts. Therefore, the service life of this manual reset snap-action temperature controller can reach 20,000 cycles or more.

[0030] The working process of this manually reset snap-action temperature controller is as follows: When the temperature of the heating element of the temperature-controlled device rises to the operating temperature of this manual reset snap-action temperature controller, the bimetallic disc 2 flips upward, and through the transmission rod 3, pushes the moving spring 8-1 to swing upward, causing the moving contact 8-2 to disengage from the stationary contact 10-2, and the heating element is de-energized.

[0031] When the temperature of the heating element gradually decreases and it needs to be reset and powered on, push the reset handle 9 downwards by hand. The resulting reset pressure is decomposed into two equal and vertically downward components through the two wings on the lower part of the reset handle 9. These components act on point A of the bimetallic disc 2 through the first reset rod 4, which is movably connected to the fourth through hole 9-1 and the first through hole 6-1, and on point B of the bimetallic disc 2 through the second reset rod 5, which is movably connected to the fifth through hole 9-2 and the second through hole 6-2. This causes the bimetallic disc 2 to reset and flip downwards. At the same time, the transmission rod 3 falls onto the bimetallic disc 2 under its own weight and the elastic force of the moving spring 8-1. The moving contact 8-2 closes with the stationary contact 10-2, and the heating element is powered on and heats up.

[0032] This manual reset snap-action thermostat, with its double reset rod structure and flat rectangular shape, has a relatively short body height, making it suitable for applications with strict requirements on thermostat installation height, such as instantaneous electric water heaters. One existing cylindrical manual reset snap-action thermostat model is KSD301-RG, with a body height of 17.5mm; another model of this manual reset snap-action thermostat (flat rectangular shape) is KSD312-RG, with a body height of 7.6mm.

Claims

1. A manual reset snap-action thermostat, comprising a cover (1), a bimetallic disc (2), a transmission rod (3), a base (6), a bottom cover (7), a moving contact assembly (8), and a stationary contact assembly (10), arranged sequentially from top to bottom as the bottom cover (7), the moving contact assembly (8), the stationary contact assembly (10), the base (6), the transmission rod (3), the cover (1), and the bimetallic disc (2), wherein the bottom cover (7) is connected to the base (6), one end of the moving contact assembly (8), and one end of the stationary contact assembly (10). The bimetallic disc (2) is fixedly connected by a fixed stake (12) and a rivet (11). The outer periphery of the bimetallic disc (2) is placed in the annular flat groove formed between the bottom of the base (6) and the bottom of the cover (1) and is in movable contact with the annular flat groove. The upper end of the vertical transmission rod (3) is in movable contact with the protrusion in the middle of the moving spring (8-1) of the moving contact assembly (8). The lower end of the transmission rod (3) is in movable contact with the center of the bimetallic disc (2). The bimetallic disc (2) is characterized in that: It also includes a first reset rod (4), a second reset rod (5), and a reset handle (9); the base (6) has a third through hole (6-3) in the center, and the base (6) on both sides of the third through hole (6-3) has a first through hole (6-1) and a second through hole (6-2) equidistant from it; the lower front and rear wings of the reset handle (9) are respectively provided with a fourth through hole (9-1) and a fifth through hole (9-2); the first lower rod (4-1) of the first reset rod (4) is flexibly connected to the first through hole (6-1). The first upper rod (4-3) of the first reset rod (4) is movably sleeved with the fourth through hole (9-1); the second lower rod (5-1) of the second reset rod (5) is movably sleeved with the second through hole (6-2); the second upper rod (5-3) of the second reset rod (5) is movably sleeved with the fifth through hole (9-2); the lower end of the first reset rod (4) and the lower end of the second reset rod (5) are respectively movably contacted with the bimetallic disc (2).

2. The manual reset bump bump thermostat of claim 1, wherein: The first reset rod (4) is composed of a first lower rod (4-1), a first limiting rod (4-2) and a first upper rod (4-3). The lower plane of the first limiting rod (4-2) is in contact with the base (6), and the upper plane of the first limiting rod (4-2) is in contact with the lower plane of the front wing of the reset handle (9). The lower end of the first lower rod (4-1) is spherical and is in contact with the bimetallic disc (2), and its contact point is A.

3. The manual reset bump bump thermostat of claim 1, wherein: The second reset rod (5) consists of a second lower rod (5-1), a second limiting rod (5-2), and a second upper rod (5-3). The lower plane of the second limiting rod (5-2) is in contact with the base (6), and the upper plane of the second limiting rod (5-2) is in contact with the lower plane of the rear wing of the reset handle (9). The lower end of the second lower rod (5-1) is spherical and is in contact with the bimetallic disc (2), and its contact point is B.

4. The manual reset bump bump thermostat of claim 1, wherein: The bimetallic disc (2) has a center O, the contact point A and the contact point B are located on the same diameter, and = , the length of the straight line is 0.55-0.65 times the diameter of the bimetallic disc (2).

5. The manual reset bump bump thermostat of claim 1, wherein: The reset handle (9) is in active contact with the rectangular through hole in the middle of the bottom cover (7).

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