A constant force spring and its processing technology

Abstract

The present invention discloses a constant force spring, comprising a No. 1 spring assembly and a No. 2 spring assembly, wherein the outer surface of the No. 1 spring assembly is provided with a No. 1 extension plate near the No. 2 spring assembly, and the outer surface of the No. 2 spring assembly is provided with a No. 2 extension plate near the No. 1 spring assembly. The key points of the technical solution are that, by dividing the original constant force spring into two spring assemblies, the spring assemblies can be assembled after being manufactured, which can greatly reduce the difficulty of processing and facilitate the replacement of damaged spring assemblies. By respectively providing connecting grooves on both sides of the spring assembly and providing rubber strips on the inner surface of the connecting grooves, it can play a role of temporary connection when the spring assembly is damaged, thereby improving the safety of the constant force spring in use. By controlling the speed of temperature cooling during tempering and performing slow cooling, the service life and quality of the spring assembly can be improved.

Description

Technical Field

[0001] The invention relates to the field of springs, and in particular to a constant force spring and a processing technology thereof. Background Art

[0002] Constant force springs are disc-shaped springs made of elastic steel wires or steel strips with the same cross-section, such as hairsprings and springs. However, their constant force is limited by the surface of the disc and cannot meet more constant force technical needs. The existing cylindrical, tower-shaped, conical, olive-shaped, and diamond-shaped spring structures are mostly wound with elastic steel wires of uniform thickness;

[0003] The existing constant force spring and its processing technology have certain disadvantages when used: (1) Difficulty in production: Since the existing constant force spring is a constant force spring structure set at both ends of the workpiece, in order to ensure the constant elastic force on both sides, it is necessary to detect the length, width, thickness, etc. of the workpiece before processing. Secondly, during processing, one end of the workpiece is bent first, and then the other end of the workpiece is bent. At the same time, during forming, it is also necessary to accurately measure the bending position and bending length, which affects the processing progress; (2) Insufficient safety: When the constant force spring is used, if the spring is broken, the spring will splash under the action of its own elastic force, which may cause certain dangers; (3) Fast tempering speed: Since the constant force spring needs to be tempered to eliminate the internal stress in the workpiece after bending, the existing constant force spring cools down quickly after tempering. Since the workpiece has just undergone high-temperature tempering and suddenly cools down, cracks are likely to appear inside the workpiece, affecting the quality of the constant force spring. For this reason, we propose a constant force spring and its processing technology. Summary of the invention

[0004] In order to overcome the deficiencies of the prior art, the object of the present invention is to provide a constant force spring and a processing technology thereof, which divides the original constant force spring into two spring components, so that the spring components are manufactured and then assembled, which can greatly reduce the difficulty of processing and facilitate the replacement of damaged spring components, avoiding the need for overall replacement and wasting resources. By providing a latch pin on the outer surface of the extension plate and opening a latch slot inside the docking slot, which can cooperate with the latch pin on the outer surface of the extension plate, the extension plate can be fixed to prevent the extension plate from sliding, and by providing protrusions at the center of the inner top surface of the docking slot and on both sides of the inner bottom surface of the docking slot, the movement of the extension plate can be further restricted. Space, by opening connecting grooves on both sides of the spring assembly and arranging rubber strips on the inner surface of the connecting grooves, it can play a role of temporary connection when the spring assembly is damaged, avoiding the spring assembly from breaking and splashing, and improving the safety of the constant force spring. By controlling the temperature cooling speed during tempering and performing slow cooling, it can avoid cracks in the constant force spring caused by excessive cooling, thereby improving the service life and quality of the spring assembly. Before forming, the workpiece is subjected to continuous composite tension and compression, so that the tension on both sides of the workpiece can be fully adjusted, the characteristics of tension and bending are introduced, the bending stress state of the strip is improved, and the residual stress of the workpiece is reduced by positive and reverse bending, further increasing the stability of the workpiece.

[0005] To achieve the above object, the technical solution adopted by the present invention is:

[0006] A constant force spring comprises a No. 1 spring assembly and a No. 2 spring assembly, wherein a No. 1 extension plate is provided on the outer surface of the No. 1 spring assembly near the No. 2 spring assembly, and a No. 2 extension plate is provided on the outer surface of the No. 2 spring assembly near the No. 1 spring assembly, and a docking plate is provided on the outer surfaces of the No. 2 extension plate and the No. 1 extension plate.

[0007] By dividing the original constant force spring into two spring components, the spring components can be manufactured and then assembled, which can greatly reduce the processing difficulty and facilitate the replacement of damaged spring components, avoiding the need for overall replacement and wasting resources.

[0008] Preferably, a No. 1 bayonet is welded on the top outer surface of the No. 1 extension plate near the No. 2 extension plate, and a No. 2 bayonet is welded on the top outer surface of the No. 2 extension plate near the No. 1 extension plate.

[0009] Preferably, a convex pin is welded on one end of the first extension plate close to the second extension plate, and a groove is formed on one end of the second extension plate close to the first extension plate.

[0010] By providing protrusions at the center of the inner top surface of the docking slot and at both sides of the inner bottom surface of the docking slot, the activity space of the extension plate can be further limited.

[0011] Preferably, a docking slot is formed through the front outer surface of the docking plate, and card slots are formed at both sides of the inner top surface of the docking slot.

[0012] By arranging a latch on the outer surface of the extension plate and opening a latch groove inside the docking slot, the extension plate can be fixed to prevent the extension plate from sliding by cooperating with the latch on the outer surface of the extension plate.

[0013] Preferably, a No. 1 protrusion is bonded to the inner bottom surface of the docking slot near both sides, and a No. 2 protrusion is bonded to the middle position of the inner top surface of the docking slot.

[0014] Preferably, connecting grooves are provided on both side outer surfaces of the No. 1 spring assembly, rubber strips are inlaid on the inner surfaces of the connecting grooves, and a T-shaped pin is provided on the outer surface of the rubber strip on one side close to the No. 1 spring assembly.

[0015] By opening connecting grooves on both sides of the spring assembly and arranging rubber strips on the inner surface of the connecting grooves, a temporary connection can be achieved when the spring assembly is damaged, thereby preventing the spring assembly from breaking and splashing, and improving the safety of the constant force spring.

[0016] A processing technology for a constant force spring comprises the following steps:

[0017] (I) Raw material processing: Use a slotting machine to slot the workpiece and the butt plate, and then use a grinder to grind the workpiece and the butt plate;

[0018] (II) Injection molding: Place the polished workpiece into the injection mold so that the rubber wraps the surface of the workpiece, and then remove the rubber at the upper and lower ends of the workpiece to complete the injection molding;

[0019] (III) Forming: After injection molding, the end of the workpiece away from the bayonet is placed in a spring winding machine for continuous composite drawing and pressing, and the other end of the workpiece is bent to form an extension plate to obtain a spring assembly;

[0020] (IV) Preliminary inspection: Use a vernier caliper and a micrometer to inspect the dimensions of the spring assembly;

[0021] (V) Cleaning and tempering: After preliminary inspection, the spring is placed in an ultrasonic cleaner for cleaning for 3-5 minutes. After cleaning, it is placed in a tempering furnace for tempering and cooled to obtain a formed spring;

[0022] (VI) Secondary inspection: Use a vernier caliper and a micrometer to inspect the dimensions of the formed spring;

[0023] (VII) Splicing: Select two formed springs after secondary testing, insert the extension plates into the docking slots 8 respectively, and put them into the packaging box for packaging.

[0024] Preferably, in step (I), the raw materials include a workpiece and a docking plate, and the workpiece is slotted: first, connecting grooves are respectively opened on both sides of the workpiece, and a latch pin is welded at one end of the front side of the workpiece, and then a groove is opened or a protruding pin is welded at one end of the workpiece close to the latch pin; the docking plate is slotted: first, a docking slot is opened inside the docking plate using a slotting machine, and latch slots are opened inside the docking slot near both sides, the width of the workpiece is 3.8-4.2 mm, and the thickness of the workpiece is 0.055-0.065 mm.

[0025] Preferably, in the step (III), continuous composite tension and compression forming is performed: first, the workpiece is placed into a spring winding machine with its front side facing upward, so that the workpiece is bent into an arc with a bending radius of 15-20 mm, the workpiece is placed into the spring winding machine with its front side facing downward again, and bent in the reverse direction, and the above steps are repeated 3-5 times, and then the workpiece is bent multiple times with its front side facing upward, and the extension plate is cut off after bending and forming, so that the length of the extension plate is 3.3-3.7 mm, the outer diameter of the spring assembly is 4.8-5.2 mm, the distance from the center point of the spring assembly to the plane where the extension plate is located is 0.3 mm, and the number of turns of the spring assembly is greater than 2.5 turns.

[0026] Before forming, by performing continuous composite tension and compression on the workpiece, the tension on both sides of the workpiece can be fully adjusted, the characteristics of stretching and bending are introduced, the bending stress state of the strip is improved, and the residual stress of the workpiece is reduced by positive and reverse bending, further increasing the stability of the workpiece.

[0027] Preferably, in the step (V), the temperature of the tempering furnace is 240-280°C, the heating time is 6-9 min, the cooling rate is 2-3°C min, and the process stops after cooling to room temperature.

[0028] By controlling the cooling speed during tempering and performing slow cooling, it is possible to avoid cracks in the constant force spring due to excessive cooling, thereby improving the service life and quality of the spring assembly.

[0029] Compared with the prior art, the present invention has the following beneficial effects:

[0030] 1. By dividing the original constant force spring into two spring components, the spring components can be manufactured and assembled later, which can greatly reduce the difficulty of processing and facilitate the replacement of damaged spring components, avoiding the need for overall replacement and wasting resources;

[0031] 2. By providing a latch on the outer surface of the extension plate and opening a latch groove inside the docking slot, the latch can cooperate with the latch on the outer surface of the extension plate to fix the extension plate and prevent the extension plate from sliding;

[0032] 3. By providing protrusions at the center of the inner top surface of the docking slot and at both sides of the inner bottom surface of the docking slot, the activity space of the extension plate can be further limited;

[0033] 4. By opening connection grooves on both sides of the spring assembly and setting rubber strips on the inner surface of the connection grooves, it can play a role of temporary connection when the spring assembly is damaged, avoiding the spring assembly from breaking and splashing, and improving the safety of the constant force spring;

[0034] 5. By controlling the cooling speed during tempering and performing slow cooling, it is possible to avoid cracks in the constant force spring due to excessive cooling, thereby improving the service life and quality of the spring assembly;

[0035] 6. Before forming, by continuously compounding and pulling the workpiece, the tension on both sides of the workpiece can be fully adjusted, the characteristics of stretching and bending are introduced, the bending stress state of the strip is improved, and the residual stress of the workpiece is reduced by positive and negative bending, further increasing the stability of the workpiece. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 It is a schematic diagram of the overall structure of a constant force spring in a constant force spring of the present invention;

[0037] Figure 2 This is a structural diagram of a constant force spring of the present invention after a No. 1 spring assembly and a No. 2 spring assembly are separated;

[0038] Figure 3 A constant force spring of the present invention Figure 2 A magnified view of middle;

[0039] Figure 4 This is a structural diagram of a butt joint plate in a constant force spring of the present invention;

[0040] Figure 5 It is a cross-sectional view of a butt joint plate in a constant force spring of the present invention;

[0041] Figure 6 It is a cross-sectional view of a spring assembly No. 1 in a constant force spring of the present invention;

[0042] Figure 7 The present invention is a flowchart of a constant force spring and its processing technology.

[0043] In the figure: 1. Spring assembly No. 1; 2. Spring assembly No. 2; 3. Extension plate No. 1; 4. Extension plate No. 2; 5. Docking plate; 6. Pin No. 1; 7. Pin No. 2; 8. Docking slot; 9. Slot; 10. Rubber strip. DETAILED DESCRIPTION

[0044] In order to make the technical means, creative features, objectives and effects achieved by the present invention easy to understand, the present invention is further explained below in conjunction with specific implementation methods.

[0045] Example 1

[0046] Reference Figure 1-5 As shown, a constant force spring comprises a No. 1 spring assembly 1 and a No. 2 spring assembly 2, wherein a No. 1 extension plate 3 is provided on the outer surface of the No. 1 spring assembly 1 near the No. 2 spring assembly 2, and a No. 2 extension plate 4 is provided on the outer surface of the No. 2 spring assembly 2 near the No. 1 spring assembly 1, and a docking plate 5 is provided on the outer surfaces of the No. 2 extension plate 4 and the No. 1 extension plate 3.

[0047] By dividing the original constant force spring into two spring components, the spring components can be manufactured and then assembled, which can greatly reduce the processing difficulty and facilitate the replacement of damaged spring components, avoiding the need for overall replacement and wasting resources.

[0048] Reference Figure 3 As shown, a first bayonet 6 is welded on the top outer surface of the first extension plate 3 near the second extension plate 4 , and a second bayonet 7 is welded on the top outer surface of the second extension plate 4 near the first extension plate 3 .

[0049] Reference Figure 3 A convex pin is welded on one end of the first extension plate 3 close to the second extension plate 4, and a groove is formed on one end of the second extension plate 4 close to the first extension plate 3.

[0050] Reference Figure 4-5 As shown, a docking slot 8 is formed through the front outer surface of the docking plate 5 , and clamping slots 9 are formed at both sides of the inner top surface of the docking slot 8 .

[0051] By providing protrusions at the center of the inner top surface of the docking slot 8 and at both sides of the inner bottom surface of the docking slot 8, the movable space of the extension plate can be further limited.

[0052] By providing a latch on the outer surface of the extension plate and opening a latch groove 9 inside the docking slot 8, the extension plate can be fixed to prevent the extension plate from sliding by cooperating with the latch on the outer surface of the extension plate.

[0053] Reference Figure 5 The inner bottom surface of the docking slot 8 is bonded with a No. 1 protrusion near both sides, and the inner top surface of the docking slot 8 is bonded with a No. 2 protrusion at the middle position.

[0054] Reference Figure 6 As shown, connecting grooves are provided on both sides of the outer surface of the No. 1 spring assembly 1, and rubber strips 10 are embedded in the inner surface of the connecting grooves. A T-shaped pin is provided on the outer surface of the rubber strip 10 close to the No. 1 spring assembly 1.

[0055] By opening connecting grooves on both sides of the spring assembly and arranging rubber strips 10 on the inner surface of the connecting grooves, a temporary connection can be provided when the spring assembly is damaged, thereby preventing the spring assembly from breaking and splashing, and improving the safety of the constant force spring.

[0056] Before use, insert the extension plates of the two spring assemblies into the docking slots 8 from both sides of the docking plate 5, so that the latches at the top of the No. 1 extension plate 3 and the No. 2 extension plate 4 are respectively inserted into different latch slots 9, and the extension plates and the docking plate 5 are connected together to complete the combination, which can greatly reduce the processing difficulty and facilitate the replacement of damaged spring assemblies, avoiding the need for overall replacement and wasting resources.

[0057] When the spring assembly breaks during deformation, the fragments splash outward under the action of elastic force. However, since rubber strips 10 are bonded to the outer surfaces of both sides of the spring assembly, the broken fragments can be pulled to prevent the spring assembly fragments from splashing, thereby improving the safety of the constant force spring. After that, the damaged spring assembly is manually pulled outward, and the docking plate 5 is pressed at the same time, so that the pin slides out of the slot 9, and the damaged spring assembly can be removed. After that, the new spring assembly extension plate is inserted into the docking slot 8 to complete the replacement, avoiding the need for overall replacement and improving resource utilization.

[0058] When in use, the No. 1 spring assembly 1 and the No. 2 spring assembly 2 are respectively fixed on both sides of the force-bearing member, and then the force-bearing member is fitted with the surface of the docking plate 5. The docking plate 5 is squeezed by the force-bearing member, so that the docking plate 5 drives the extension plates on both sides to move backward together, and the extension plates straighten the spring assembly. Since the spring assembly needs to restore its original bent shape, it exerts an opposite pulling force on the extension plate and transmits the pulling force to the force-bearing member.

[0059] Example 2

[0060] Reference Figure 7 As shown, a processing technology of a constant force spring includes the following steps:

[0061] (I) Raw material processing: a slotting machine is used to slot the workpiece and the docking plate 5, and then a grinder is used to grind the workpiece and the docking plate 5. The raw materials include the workpiece and the docking plate 5. Workpiece slotting: firstly, connecting slots are respectively opened on both sides of the workpiece, and a latch pin is welded at one end of the front of the workpiece, and then a groove is opened or a convex pin is welded at one end of the workpiece close to the latch pin; docking plate 5 slotting: firstly, a slotting machine is used to open a docking slot 8 inside the docking plate 5, and latch slots 9 are opened near both sides of the docking slot 8. The width of the workpiece is 4.0 mm, and the thickness of the workpiece is 0.060 mm;

[0062] (II) Injection molding: Place the polished workpiece into the injection mold so that the rubber wraps the surface of the workpiece, and then remove the rubber at the upper and lower ends of the workpiece to complete the injection molding;

[0063] (III) Forming: After injection molding, the end of the workpiece away from the latch is placed in a spring winding machine for continuous composite tension and compression forming, and the other end of the workpiece is bent to form an extension plate to obtain a spring assembly. Continuous composite tension and compression forming: first, the workpiece is placed in the spring winding machine with the front side facing upward, so that the workpiece is bent into an arc with a bending radius of 20 mm. The workpiece is placed in the spring winding machine with the front side facing downward again, and reversely bent. The above bending is repeated 3-5 times, and then the workpiece is bent multiple times with the front side facing upward. After bending and forming, the extension plate is cut off, so that the length of the extension plate is 3.5 mm, the outer diameter of the spring assembly is 5.0 mm, the distance from the center point of the spring assembly to the plane where the extension plate is located is 0.3 mm, and the number of turns of the spring assembly is equal to 2.5 turns. Before forming, by continuously composite tension and compression of the workpiece, the tension on both sides of the workpiece can be fully adjusted, the characteristics of tension and bending are introduced, the bending stress state of the strip is improved, and the residual stress of the workpiece is reduced by positive and reverse bending, further increasing the stability of the workpiece;

[0064] (IV) Preliminary inspection: Use a vernier caliper and a micrometer to inspect the dimensions of the spring assembly;

[0065] (V) Cleaning and tempering: The spring after preliminary inspection is placed in an ultrasonic cleaner for cleaning for 4 minutes, and then placed in a tempering furnace for tempering. The formed spring is cooled and the temperature of the tempering furnace is 260°C, the heating time is 8 minutes, and the cooling rate is 3°C min. The spring is cooled to room temperature and then stopped. By controlling the cooling rate during tempering and performing slow cooling, cracks in the constant force spring due to excessive cooling can be avoided, thereby improving the service life and quality of the spring assembly.

[0066] (VI) Secondary inspection: Use a vernier caliper and a micrometer to inspect the dimensions of the formed spring;

[0067] (VII) Splicing: Select two formed springs after secondary testing, insert the extension plates into the docking slots 8 respectively, and put them into the packaging box for packaging.

[0068] The above shows and describes the basic principles and main features of the present invention and the advantages of the present invention. It should be understood by those skilled in the art that the present invention is not limited to the above embodiments. The above embodiments and descriptions are only for explaining the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, which fall within the scope of the present invention to be protected. The scope of protection of the present invention is defined by the attached claims and their equivalents.

Claims

1. A constant force spring, comprising a first spring assembly (1) and a second spring assembly (2), characterized in that: A first extension plate (3) is provided on the outer surface of the first spring assembly (1) near the second spring assembly (2), a second extension plate (4) is provided on the outer surface of the second spring assembly (2) near the first spring assembly (1), and a butt joint plate (5) is sleeved on the outer surfaces of the second extension plate (4) and the first extension plate (3); The first spring assembly (1) and the second spring assembly (2) are respectively fixed on both sides of the force-bearing member, and then the force-bearing member is fitted onto the surface of the docking plate (5); A first bayonet (6) is welded to the top outer surface of the first extension plate (3) at a position close to the second extension plate (4), and a second bayonet (7) is welded to the top outer surface of the second extension plate (4) at a position close to the first extension plate (3); A protruding pin is welded to one end of the first extension plate (3) close to the second extension plate (4), and a groove is formed at one end of the second extension plate (4) close to the first extension plate (3); A docking slot (8) is provided through the front outer surface of the docking plate (5), and clamping slots (9) are provided at both sides of the inner top surface of the docking slot (8).

2. A constant force spring according to claim 1, characterized in that: The inner bottom surface of the docking slot (8) is bonded with a No. 1 protrusion near both sides, and the inner top surface of the docking slot (8) is bonded with a No. 2 protrusion at the middle position.

3. A constant force spring according to claim 1, characterized in that: The outer surfaces of both sides of the first spring assembly (1) are provided with connection grooves, the inner surfaces of the connection grooves are inlaid with rubber strips (10), and the outer surface of the rubber strip (10) close to the first spring assembly (1) is provided with a T-shaped pin.

4. A processing technology for a constant force spring according to any one of claims 1 to 3, characterized in that: The following steps are involved: (I) Raw material processing: using a slotting machine to slot the workpiece and the docking plate (5), and then using a grinder to grind the workpiece and the docking plate (5). The raw materials include the workpiece and the docking plate (5). Workpiece slotting: firstly, connecting slots are respectively opened on both sides of the workpiece, and a latch pin is welded at one end of the front of the workpiece, and then a groove is opened or a convex pin is welded at one end of the workpiece close to the latch pin; docking plate (5) slotting: firstly, a docking slot (8) is opened inside the docking plate (5) using a slotting machine, and latch slots (9) are opened near both sides of the docking slot (8); (II) Injection molding: Place the polished workpiece into the injection mold so that the rubber wraps the surface of the workpiece, and then remove the rubber at the upper and lower ends of the workpiece to complete the injection molding; (III) Forming: After injection molding, the end of the workpiece away from the bayonet is placed in a spring winding machine for continuous composite drawing and pressing, and the other end of the workpiece is bent to form an extension plate to obtain a spring assembly; (IV) Preliminary inspection: Use a vernier caliper and a micrometer to inspect the dimensions of the spring assembly; (V) Cleaning and tempering: After preliminary inspection, the spring is placed in an ultrasonic cleaner for cleaning for 3-5 minutes. After cleaning, it is placed in a tempering furnace for tempering and cooled to obtain a formed spring; (VI) Secondary inspection: Use a vernier caliper and a micrometer to inspect the dimensions of the formed spring; (VII) Splicing: Select two formed springs after secondary testing, insert the extension plates into the docking slots (8) respectively, and pack them into packaging boxes.

5. The processing technology of a constant force spring according to claim 4, characterized in that: In the step (III), continuous composite tension and compression forming is performed: first, the workpiece is placed into a spring winding machine with its front side facing upward, so that the workpiece is bent into an arc with a bending radius of 15-20 mm, and the workpiece is placed into the spring winding machine with its front side facing downward again, and bent in the reverse direction, and the above bending is repeated 3-5 times, and then the workpiece is placed with its front side facing upward and bent multiple times, and the extension plate is cut after bending.

6. The processing technology of a constant force spring according to claim 4, characterized in that: In the step (V), the temperature of the tempering furnace is 240-280°C, the heating time is 6-9 min, the cooling rate is 2-3°C min, and the process stops after cooling to room temperature.

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