A semi-automatic defrosting type pressure thermostat with auxiliary switch

Abstract

A half-automatic defrosting type pressure temperature controller with auxiliary switch belongs to the technical field of pressure temperature controller. The pressure temperature controller comprises a switch box assembly, a push rod, a bellows, a temperature adjusting and controlling mechanism and a defrosting lock catch tripping mechanism, and an auxiliary switch and an auxiliary switch linkage mechanism are further arranged between a main switch and an adjusting plate. An auxiliary moving contact of the auxiliary switch is connected with a stationary contact through an auxiliary contact piece, and an auxiliary stationary contact is connected with an H terminal. An auxiliary screw, an auxiliary tension spring and an auxiliary piece handle of the auxiliary switch linkage mechanism are sequentially connected, the screw rod of the auxiliary screw passes through a hole in the upper part of the adjusting plate, the screw head is in contact with the outer side of the adjusting plate, and the left end of the auxiliary piece handle is fixedly connected with the upper end of the auxiliary contact piece. The structure can realize synchronous control of the opening and closing of the auxiliary switch and the disconnection and connection of the electric heating defrosting device, and can automatically return the single-door refrigerator to the normal temperature adjusting and controlling working cycle after rapid defrosting.

Description

Technical Field

[0001] This invention relates to the field of pressure thermostat technology, and particularly to a semi-automatic defrosting pressure thermostat with an auxiliary switch. Background Technology

[0002] Pressure-type thermostats are widely used in the refrigeration control of refrigerators, freezers, and other appliances. They control the temperature by sensing the rise and fall of the internal temperature of the refrigerator and triggering a microswitch to turn the compressor on and off. In a single-door direct-cooling refrigerator, the microswitch typically operates below 0°C (e.g., -6 to -18°C). Over time, frost can accumulate on the evaporator surface. If the frost layer is too thick, it can affect refrigeration efficiency, necessitating periodic defrosting. Semi-automatic defrosting thermostats are used in this application. When thick frost is detected, the user manually presses the defrost button on the thermostat, turning off the microswitch. The defrosting mechanism automatically disengages and returns to the normal temperature control cycle only when the internal temperature gradually rises above 0°C (approximately 2 to 8°C).

[0003] Chinese patent publication CN2849941Y discloses a utility model entitled "Semi-automatic Frosting Refrigerator Temperature Controller". The microswitch 6 comprises only one set of single-pole single-throw switches used to control the on / off state of the compressor.

[0004] The aforementioned semi-automatic defrosting refrigerator temperature controller has the following disadvantages: Pressing the defrost button (i.e., the defrosting shaft 13) disconnects the microswitch 6, stopping the compressor. The frost on the evaporator surface inside the refrigerator melts slowly as the ambient temperature naturally rises above 0°C (approximately 2-8°C). When the defrost reset temperature is reached, the defrost mechanism automatically disengages and returns to the normal temperature control cycle. Since natural defrosting takes a long time, typically around 2 hours, prolonged compressor inactivity severely impacts food preservation. Therefore, some refrigerator manufacturers propose adding an electric defrosting device to the evaporator of single-door refrigerators. This device requires manual operation to activate during defrosting and deactivate when the refrigerator resumes normal operation. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide a semi-automatic defrosting pressure thermostat with an auxiliary switch. When the defrosting lock release mechanism is in the released state, the auxiliary switch remains open; when the defrosting lock release mechanism is in the locked state, the auxiliary switch remains on; thereby realizing semi-automatic rapid defrosting of a single-door refrigerator, and automatically returning to the normal temperature control state after defrosting is completed.

[0006] The technical solution proposed in this invention is as follows: A semi-automatic defrosting pressure-type temperature controller with an auxiliary switch includes a switch box assembly, a push rod, a bellows and capillary tube, a pressure plate mounted on the main body, an adjusting plate, a defrosting plate, a spring, a roller, a leaf spring, a defrosting screw, a bracket, an adjusting wheel, an adjusting shaft, a defrosting shaft, a tension spring, a spring nut, and a temperature adjusting screw. The switch box assembly includes a switch box, a stationary contact, a moving contact, a contact screw, an L terminal, a spring, a C terminal, and a moving contact piece. The main switch is mainly composed of the moving contact piece, the spring, the moving contact, the stationary contact, the L terminal, the C terminal, and the contact screw. The temperature control mechanism is mainly composed of the pressure plate, the adjusting plate, the tension spring, the spring nut, the temperature adjusting screw, the adjusting shaft, and the adjusting wheel. The defrosting lock release mechanism is mainly composed of the defrosting plate and the adjusting plate. The system comprises a leaf spring, rollers, defrosting screws, spring plates, and a defrosting shaft. It also includes an auxiliary switch and an auxiliary switch linkage mechanism. The auxiliary switch mainly consists of an auxiliary contact piece, an auxiliary moving contact, an auxiliary stationary contact, and an H-terminal. The H-terminal is located on the switch box. One end of the auxiliary contact piece is riveted to the stationary contact, and the other end of the auxiliary contact piece is riveted to the auxiliary moving contact. The auxiliary stationary contact is riveted to the H-terminal. The auxiliary switch linkage mechanism mainly consists of an auxiliary tension spring, an auxiliary screw, and an auxiliary contact handle. One end of the auxiliary tension spring is hooked to one end of the auxiliary contact handle, and the other end of the auxiliary tension spring is threadedly interference-fitted with the auxiliary screw, which passes through the upper hole of the adjustment plate from the right side. The left end of the auxiliary contact handle is fixedly connected to the other end of the auxiliary contact piece.

[0007] One end of the auxiliary tension spring is interference-fitted with the cross arm of one end of the auxiliary contact plate handle. The auxiliary screw shaft passes through the upper hole of the adjusting plate and is threadedly interference-fitted with the other end of the auxiliary tension spring. The diameter of the auxiliary screw head is larger than the diameter of the upper hole of the adjusting plate. The other end of the auxiliary contact plate is pre-bent to the left so that the auxiliary moving contact and the auxiliary stationary contact are in a relatively separated state when static. The auxiliary contact plate handle is made of insulating plastic, and the left end of the auxiliary contact plate handle is fixedly connected to the other end of the auxiliary contact plate by a clamping injection molding method.

[0008] Compared with the prior art, the present invention has the following significant effects: This invention is based on the existing semi-automatic defrosting pressure thermostat, with an auxiliary switch and an auxiliary switch linkage mechanism. The auxiliary switch linkage mechanism enables the linkage between the auxiliary switch and the defrosting lock release mechanism, thereby enabling the closing and opening of the auxiliary switch to be synchronously controlled with the connection and disconnection of the electric defrosting device installed near the evaporator, so that the refrigerator automatically returns to the normal temperature control cycle after the rapid defrosting is completed.

[0009] The present invention provides a semi-automatic defrosting pressure thermostat with an auxiliary switch, which is particularly suitable for single-door refrigerator applications. Attached Figure Description

[0010] Figure 1This is a schematic diagram of a semi-automatic defrosting pressure thermostat with an auxiliary switch according to an embodiment of the present invention, in the defrosting lock release mechanism in the released state. The tension spring, spring nut, and temperature adjustment screw are omitted in the figure.

[0011] Figure 2 yes Figure 1 The diagram shows a semi-automatic defrosting pressure thermostat with an auxiliary switch in the defrosting lock release mechanism in the locked state. The tension spring, spring nut, and temperature adjustment screw are omitted in the diagram.

[0012] Figure 3 yes Figure 1 A top-view structural diagram.

[0013] Figure 4 yes Figure 3 A schematic diagram of the AA section. Detailed Implementation

[0014] The present invention will be further described in detail through the following embodiments.

[0015] See Figures 1-4As shown, a semi-automatic defrosting pressure thermostat with an auxiliary switch includes a switch box assembly, a push rod 2, a bellows 3 and a capillary tube, a pressure plate 8 mounted on the main body 6, an adjusting plate 7, a defrosting plate 5, a spring 4, a roller 9, a leaf spring 10, a defrosting screw 11, a bracket 12, an adjusting wheel 13, an adjusting shaft 14, a defrosting shaft 15, a tension spring 16, a spring nut 17, and a temperature adjusting screw 18. The switch box assembly includes a switch box 1, a stationary contact 21, and a moving contact 22. The main switch is mainly composed of the moving contact 29, the spring 25, the moving contact 22, the stationary contact 21, the L terminal 24, the C terminal 27, and the contact screw 23. The temperature control mechanism is mainly composed of the pressure plate 8, the adjusting plate 7, the tension spring 16, the spring nut 17, the temperature adjusting screw 18, the adjusting shaft 14, and the adjusting wheel 13. The defrost lock release mechanism is mainly composed of the following components: head 22, contact screw 23, L terminal 24, spring 25, C terminal 27, and moving contact piece 29. The system comprises a defrost plate 5, an adjusting plate 7, a leaf spring 10, a roller 9, a defrost screw 11, a spring 4, and a defrost shaft 15. It also includes an auxiliary switch and an auxiliary switch linkage mechanism. The auxiliary switch mainly consists of an auxiliary contact piece 28, an auxiliary moving contact 30, an auxiliary stationary contact 31, and an H terminal 26. The H terminal 26 is located on the switch box 1. One end of the auxiliary contact piece 28 is riveted to the stationary contact 21, and the other end of the auxiliary contact piece 28 is riveted to the auxiliary moving contact 30. The auxiliary stationary contact 31 is riveted to the H terminal 26. The auxiliary switch linkage mechanism mainly consists of an auxiliary tension spring 19, an auxiliary screw 20, and an auxiliary plate handle 32. One end of the auxiliary tension spring 19 is hooked to one end of the auxiliary plate handle 32, and the other end of the auxiliary tension spring 19 is threadedly interference-fitted with the auxiliary screw 20, which passes through the upper hole of the adjusting plate 7 from the right side. The left end of the auxiliary plate handle 32 is fixedly connected to the other end of the auxiliary contact piece 28.

[0016] One end of the auxiliary tension spring 19 is connected to the cross arm of one end of the auxiliary contact plate 32 with an interference fit. The shaft of the auxiliary screw 20 passes through the upper hole of the adjusting plate 7 and is connected to the other end of the auxiliary tension spring 19 with an interference fit. The head diameter of the auxiliary screw 20 is larger than the diameter of the upper hole of the adjusting plate 7. The other end of the auxiliary contact plate 28 is pre-bent to the left so that the auxiliary moving contact 30 and the auxiliary stationary contact 31 are in a relatively separated state when static. The auxiliary contact plate 32 is made of insulating plastic, and the left end of the auxiliary contact plate 32 is fixedly connected to the other end of the auxiliary contact plate 28 by a clamping injection molding method.

[0017] The pressure plate 8 is supported on the blade 6-1 of the main body 6 at both sides and can swing around it. A push rod 2 is provided in the middle of the vertical section of the pressure plate 8 to push the main switch of the switch box assembly to turn on and off. A hook is also provided on the vertical section to connect with the hook of the tension spring 16. A downward protrusion is provided in the middle of the horizontal section of the pressure plate 8 to contact the top of the bellows 3. The lower two protrusions of the adjusting plate 7 are supported on the second support points 6-3 on the two side walls of the main body 6 and can swing left and right around the second support points 6-3. A temperature adjusting screw 18 is installed on the adjusting plate 7 through a hole on its front side and is threaded to one end of the tension spring 16 with a spring nut 17. A leaf spring 10 is also riveted to the lower part of the adjusting plate 7. A defrosting screw 11 is provided between the upper part of the leaf spring 10 and the corresponding adjusting plate 7 to adjust the relative position between the leaf spring 10 and the adjusting plate 7. The left side protrusions of the defrost plate 5 are mounted on the first fulcrum 6-2 on the two side walls of the main body 6 and can swing around it; the right side of the defrost plate 5 has a hugging curved surface, and a roller 9 passes through the middle of the leaf spring 10. The adjusting wheel 13, which is riveted to the adjusting shaft 14, is movably placed in the middle circular hole of the bracket 12, and the defrost shaft 15 slides through the center hole of the adjusting shaft 14; the lower L-shaped hook of the defrost shaft 15 is fixedly connected to the middle of the defrost plate 5. One end of the spring 4 is fixed to one side wall of the main body 6, and the other end is in contact with the left elastic support of the defrost plate 5. The stationary contact 21 and the auxiliary contact piece 28 are riveted to the L terminal 24 at one end. The moving contact 22 is riveted to the moving contact piece 29 at one end, and the other end of the moving contact piece 29 is riveted to the C terminal 27. A spring 25 is provided in the middle of the moving contact piece 29. The contact screw 23 is used to adjust the gap between the moving contact 22 and the stationary contact 21 to obtain the required switching temperature difference. The other end of the auxiliary contact piece 28 is riveted to the auxiliary moving contact 30 and fixedly connected to the left end of the auxiliary piece handle 32. The auxiliary piece handle 32 is made of plastic insulating material and is fixed to the other end of the auxiliary contact piece 28 by clamp injection molding. The auxiliary stationary contact 31 is riveted to the H terminal 26. The L terminal 24, H terminal 26, and C terminal 27 are all riveted to the switch box 1. One end of the auxiliary tension spring 19 is hooked to the cross arm of the auxiliary plate handle 32, and the other end of the auxiliary tension spring 19 is threadedly interference-fitted to the auxiliary screw 20, which passes through the upper hole of the adjusting plate 7 from the right side. The head diameter of the auxiliary screw 20 is larger than the diameter of the upper hole of the adjusting plate 7. The upper part of the auxiliary contact piece 28 is pre-bent to the left for shaping, so that when the auxiliary contact piece 28 is static, the auxiliary moving contact 30 swings to the left to form the auxiliary switch in the open state.

[0018] The working principle of this semi-automatic defrosting pressure thermostat with auxiliary switch is as follows: When the thermostat is in temperature control mode (i.e., defrost trip mode), the reed 4 lifts the defrost plate 5 and drives the defrost shaft 15 to the highest position. At this time, the defrost plate 5 is not in contact with the leaf spring 10, the handle of the adjusting plate 7 is in contact with the cam surface of the adjusting wheel 13, and the pressure plate 8 is simultaneously subjected to the tension force of the tension spring 16 and the upward force of the bellows 3. When the temperature rises or falls, causing the upward force of the bellows 3 to increase or decrease, the vertical section of the pressure plate 8 will swing left and right, thereby pushing the main switch in the switch box assembly to turn on or off. Twisting the adjusting shaft 14 can change the tension force of the tension spring 16, so that this tension force and the upward force of the bellows 3 reach a balance, thereby obtaining different switching action temperatures of the thermostat. At this time, the auxiliary tension spring 19 is in a relaxed state, the head of the auxiliary screw 20 is disengaged from the outer side of the upper hole of the adjusting plate 7, and the auxiliary switch is in a natural separation state.

[0019] When the defrost shaft 15 is pressed, i.e., when the defrost lock is engaged, the defrost shaft 15 causes the defrost plate 5 to overcome the supporting force of the spring 4 and swing downward around the first fulcrum 6-2. The outer right side of the defrost plate 5 engages with the roller 9. This engaging action causes the leaf spring 10 to swing to the right around its lower fulcrum, causing the adjusting plate 7 to swing to the right around its lower second fulcrum 6-3. The handle of the adjusting plate 7 separates from the cam end face of the adjusting wheel 13. At the same time, the downward pointed part of the right side of the defrost plate 5 presses down on the right side of the horizontal section of the pressure plate 8, causing it to rotate clockwise. This causes the push rod 2 to move to the right, putting the main switch of the switch box assembly in the off state. Simultaneously, the outer periphery of the upper hole of the adjusting plate 7 will... The head of the auxiliary screw 20 moves to the right, tightening the auxiliary tension spring 19 to overcome the natural leftward bending force of the upper end of the auxiliary contact piece 28, allowing the auxiliary moving contact 30 to contact and connect with the auxiliary stationary contact 31. At this point, the defrosting state with the auxiliary switch on is entered. When the temperature rises to 2-8°C or above, the bellows 3 generates a large upward force to overcome the tension of the tension spring 16, causing the pressure plate 8 to swing counterclockwise. This pushes the clinging curved surface of the defrosting plate 5 to disengage from the roller 9. Under the tension of the tension spring 16, the handle of the adjusting plate 7 returns to the state of contact with the cam end face of the adjusting wheel 13. The main switch of the switch box assembly returns to the normal temperature control state, and the auxiliary switch also returns to the naturally disconnected state.

[0020] Tightening the auxiliary screw 20 adjusts the tension of the auxiliary spring 19 in defrost mode, ensuring that its tension is greater than the natural bending force of the upper part of the auxiliary contact piece 28, thus ensuring reliable connection of the auxiliary switch. Meanwhile, since the tension and stiffness of the auxiliary spring 19 are much smaller than those of the spring 16, although the handle of the adjusting plate 7 will swing slightly to the right during defrost tripping, the tension of the auxiliary spring 19 does not increase significantly. Therefore, the auxiliary spring 19 has virtually no impact on the reset action temperature of the defrost lock tripping mechanism.

[0021] The hook of the auxiliary tension spring 19 is connected to the cross arm of the auxiliary plate handle 32 by an interference fit, and will not fall off in the relaxed state; the spring coil of the auxiliary tension spring 19 is connected to the thread of the auxiliary screw 20 by an interference fit, and will not change the adjusted relative position in the relaxed state.

[0022] The adjustment process for this semi-automatic defrosting pressure-type temperature controller with auxiliary switch is as follows: First, following the normal procedure, adjust the temperature regulating screw 18, contact screw 23, and defrost screw 11 to obtain the required on / off temperatures and defrost reset temperatures for the main switch. Then, with the defrost lock in the de-energized state, adjust the auxiliary screw 20 until the auxiliary switch is just on, then tighten it slightly. By designing a suitable stiffness for the tension spring 16 and the lift of the adjusting wheel 13, the required normal operating temperature range and defrost reset temperature can be obtained. By designing a suitable stiffness for the auxiliary tension spring 19, reliable on / off operation of the auxiliary switch in the defrost lock state can be ensured. Furthermore, through reasonable design, the tension and stiffness of the auxiliary tension spring 19 are much smaller than those of the tension and stiffness of the tension spring 16. Therefore, the presence of the auxiliary tension spring 19 has virtually no impact on the reset temperature of the defrost lock release mechanism.

[0023] The temperature adjusting screw 18, contact screw 23, and defrosting screw 11 are fixed with adhesive after adjustment. The hook of the auxiliary tension spring 19 and the cross arm of the auxiliary plate handle 32 are interference-fitted, and the two will not fall off in the relaxed state. The spring coil of the auxiliary tension spring 19 and the thread of the auxiliary screw 20 are interference-fitted, and no adhesive is needed to fix the screw head to the adjusting plate 7. The two will not change their adjusted relative positions in the relaxed state.

[0024] This semi-automatic defrosting pressure-type thermostat with auxiliary switch is suitable for installation in single-door refrigerators with electric defrosting devices. The live wire is connected to the thermostat's common terminal L (24), the compressor end is connected to terminal C (27), and the electric defrosting device end is connected to terminal H (26). The other ends of both the compressor and the electric defrosting device are connected to the neutral wire. A hollow knob on the adjusting shaft 14 is used to adjust the refrigerator's normal cooling temperature. A button on the defrosting shaft 15 allows the user to manually press it for defrosting. Simply pressing this button quickly completes defrosting, keeping the food inside the refrigerator fresh.

Claims

1. A semi-automatic defrosting pressure thermostat with an auxiliary switch, comprising a switch box assembly, a push rod (2), a bellows (3) and a capillary tube, a pressure plate (8) mounted on a main body (6), an adjusting plate (7), a defrosting plate (5), a spring (4), a roller (9), a leaf spring (10), a defrosting screw (11), a bracket (12), an adjusting wheel (13), an adjusting shaft (14), a defrosting shaft (15), a tension spring (16), a spring nut (17), and a temperature adjusting screw (18). The switch box assembly comprises a switch box (1), a stationary contact (21), a moving contact (22), a contact screw (23), an L terminal (24), a bow spring (25), and a C terminal. The main switch is mainly composed of the moving contact (27), moving contact (29), moving contact (22), stationary contact (21), L terminal (24), C terminal (27), and contact screw (23). The temperature control mechanism is mainly composed of the pressure plate (8), adjusting plate (7), tension spring (16), spring nut (17), temperature adjusting screw (18), adjusting shaft (14), and adjusting wheel (13). The defrost lock release mechanism is mainly composed of the defrost plate (5), adjusting plate (7), leaf spring (10), roller (9), defrost screw (11), spring (4), and defrost shaft (15). Its characteristics are: An auxiliary switch and an auxiliary switch linkage mechanism are also provided. The auxiliary switch is mainly composed of an auxiliary contact piece (28), an auxiliary moving contact (30), an auxiliary stationary contact (31), and an H terminal (26). The H terminal (26) is located on the switch box (1). One end of the auxiliary contact piece (28) is riveted to the stationary contact (21), and the other end of the auxiliary contact piece (28) is riveted to the auxiliary moving contact (30). The auxiliary stationary contact (31) is riveted to the H terminal (26). The auxiliary switch linkage mechanism is mainly composed of an auxiliary tension spring (19), an auxiliary screw (20), and an auxiliary plate handle (32). One end of the auxiliary tension spring (19) is hooked to one end of the auxiliary plate handle (32), and the other end of the auxiliary tension spring (19) is threadedly interference-fitted to the auxiliary screw (20) which passes through the upper hole of the adjusting plate (7) from the right side. The left end of the auxiliary plate handle (32) is fixedly connected to the other end of the auxiliary contact piece (28).

2. A semi-automatic defrosting pressure-type temperature controller with an auxiliary switch according to claim 1, characterized in that: One end of the auxiliary tension spring (19) is connected to the cross arm of one end of the auxiliary plate handle (32) with an interference fit. The rod of the auxiliary screw (20) passes through the upper hole of the adjusting plate (7) and is connected to the other end of the auxiliary tension spring (19) with an interference fit. The head diameter of the auxiliary screw (20) is larger than the hole diameter of the upper hole of the adjusting plate (7).

3. A semi-automatic defrosting pressure-type temperature controller with an auxiliary switch according to claim 1, characterized in that: The other end of the auxiliary contact (28) is to be bent to the left beforehand so that the auxiliary moving contact (30) and the auxiliary stationary contact (31) are in a relatively broken state when static.

4. A semi-automatic defrosting pressure-type temperature controller with an auxiliary switch according to claim 1, characterized in that: The auxiliary plate handle (32) is made of insulating plastic, and the left end of the auxiliary plate handle (32) is fixedly connected to the other end of the auxiliary contact plate (28) by means of clamping injection molding.

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