Thin type coil spring manufacturing process and tape measure

Abstract

The present application relates to tape measure technical field, provide a kind of thin type coil spring manufacturing process and tape measure, including the following steps, quenching treatment, cryogenic treatment, tempering treatment, roll forming treatment, and the thin type coil spring is prepared;Tape measure includes tape housing, tape reel, thin type coil spring, tape band, mandrel and center nail, thin type coil spring is made by above-mentioned process;Center nail is fixedly connected with tape housing, tape reel can be rotatably set on the outside of center nail, mandrel is fixedly arranged in the inside of tape reel, and mandrel is coaxially arranged with center nail;The inner end of thin type coil spring is clamped and fixed on the outside wall of tape reel, and the outer end of thin type coil spring is hung and fixed on tape band, the space utilization of tape housing is improved in the present application, and the tape band of thickness meeting the use demand can be put in, and the length of tape band is increased.

Description

Technical Field

[0001] This invention relates to the field of measuring tape technology, and more specifically, to a manufacturing process for a thin coil spring and a measuring tape. Background Technology

[0002] As a traditional length measuring tool, the measuring tape evolved in the 19th century with the introduction of steel tapes. Combined with a spiral spring and locking mechanism, it formed the prototype of the modern measuring tape. Modern measuring tapes generally consist of a casing, tape, spring, and wheels, and are characterized by their ease of use, portability, and durability. They are widely used in construction, home decoration, surveying, and other fields.

[0003] In the design of ultra-small measuring tapes, if an 8-meter long measuring tape is to be accommodated, the traditional solution requires increasing the thickness of the measuring spring to provide sufficient recovery torque. However, this will increase the diameter of the measuring wheel, making it impossible to achieve overall miniaturization. If the diameter of the measuring wheel is reduced to pursue a smaller size, space constraints will prevent the accommodation of high-quality thick measuring tapes with a thickness of 0.12mm or more. It is difficult to meet the requirements of "miniaturization, long measuring tape, and thick measuring tape". There is a technical problem in the industry that "long and thick measuring tapes cannot be accommodated in a small size". Summary of the Invention

[0004] To overcome the shortcomings mentioned above, this invention aims to provide a manufacturing process and measuring tape for thin coil springs, which can solve the aforementioned problems.

[0005] A manufacturing process for thin coil springs includes the following steps:

[0006] S1 quenching treatment: Place the 65Mn thin steel strip of the set thickness on the continuous production line, convey it at a constant linear speed of 8 meters / minute, continuously heat it to 860℃ and keep it at a constant temperature for a preset time to make the steel strip structure completely austenitic.

[0007] S2 cryogenic treatment: After the steel strip is quenched, it is quickly transferred to the cryogenic process, cooled to -90℃ and kept at a constant temperature to inhibit the precipitation of residual austenite and promote the complete transformation of residual austenite into martensite.

[0008] S3 Tempering Treatment: After cryogenic treatment, the steel strip continues to be conveyed at a linear speed of 8 meters / minute and sent to the tempering process area. It is tempered at 370°C at a medium temperature to eliminate residual stress inside the steel strip and obtain the steel strip for making thin coil spring 3.

[0009] S4 Coiling and Forming Process: After the tempering process, the steel strip cooled to room temperature is continuously wound into a ring shape through a coiling and forming equipment, and then shaped and maintained to obtain the thin coil spring.

[0010] A measuring tape includes a casing, a wheel, a thin coil spring, a tape, a spindle, and a center pin. The thin coil spring is manufactured using the process described in claim 1. The center pin is fixedly connected to the casing. The wheel is rotatably sleeved on the outside of the center pin. The spindle is fixedly disposed inside the wheel and is coaxially arranged with the center pin. The inner end of the thin coil spring is snapped and fixed to the outer wall of the wheel, and the outer end of the spring is hooked and fixed to the tape. One end of the tape is wrapped around the outer wall of the wheel and fixed synchronously with the thin coil spring. The other end of the tape extends movably to the outside of the casing.

[0011] Furthermore, the measuring wheel has an internal mounting cavity, and the mandrel is fixedly embedded in the mounting cavity.

[0012] Furthermore, the inner end of the thin coil spring is fixed to the outer wall of the ruler wheel by a snap-fit ​​engagement, and the outer end of the thin coil spring is hooked to the end of the ruler belt by a hook, thereby fixing it to the ruler belt.

[0013] Furthermore, the ruler shell is provided with an opening for the ruler strap to enter and exit.

[0014] Compared with the prior art, the beneficial effects of the present invention are:

[0015] ① In this invention, a thin coil spring made of steel strip processed by continuous quenching and deep tempering process parameters is assembled with other components into a measuring tape. While maintaining the same external shape (casing) size as the commonly used 5-meter measuring tape on the market, the length of the measuring tape is increased to accommodate an 8-meter long measuring tape. This breaks the industry's traditional perception of the capacity of small-volume measuring tapes, improves the space utilization rate inside the casing, and allows for the insertion of measuring tapes with a thickness (0.11-0.12mm) that meets the usage requirements. The measuring tape has good straightness and is resistant to bending, enabling suspended measurement.

[0016] ② In this invention, the cost is controllable, and there is no need to use expensive special materials or complex additional mechanisms, which is conducive to large-scale production. Attached Figure Description

[0017] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used in conjunction with embodiments of the invention to explain the invention and do not constitute a limitation thereof. In the drawings:

[0018] Figure 1 A schematic diagram of the manufacturing process for a thin coil spring;

[0019] Figure 2 This is an illustration of a measuring tape. Figure 1 ;

[0020] Figure 3 This is an illustration of a measuring tape. Figure 2 ;

[0021] Figure 4 This is a schematic diagram of the internal structure of a measuring tape.

[0022] In the diagram: 1. Ruler housing; 2. Ruler wheel; 3. Thin coil spring; 4. Ruler belt; 5. Mandrel; 6. Center pin; 7. Opening; 8. Screw hole. Detailed Implementation

[0023] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. Specific Implementation

[0024] like Figure 1 As shown, a thin coil spring manufacturing process is used to improve the performance of the coil spring while reducing its thickness. It employs a continuous quenching and deep tempering method using steel strip, and specifically includes the following steps:

[0025] S1 quenching treatment: Place the 65Mn thin steel strip of the set thickness on the continuous production line, convey it at a constant linear speed of 8 meters / minute, continuously heat it to 860℃ and keep it at a constant temperature for a preset time to make the steel strip structure completely austenitic.

[0026] S2 cryogenic treatment: After the steel strip is quenched, it is quickly transferred to the cryogenic process, cooled to -90℃ and kept at a constant temperature to inhibit the precipitation of residual austenite and promote the complete transformation of residual austenite into martensite.

[0027] S3 Tempering Treatment: After cryogenic treatment, the steel strip continues to be conveyed at a linear speed of 8 meters / minute and sent to the tempering process area. It is tempered at a medium temperature of 370°C to eliminate residual stress inside the steel strip and obtain steel strip for making high elastic thin coil springs.

[0028] S4 Coiling and Forming Process: After the tempering process, the steel strip cooled to room temperature is continuously coiled into a ring shape (such as a spiral ring shape) through a coiling and forming equipment, and then shaped and maintained to obtain a thin coil spring 3.

[0029] After the above steps, the hardness of the steel strip of the thin coil spring 3 is increased to HV630 or higher, and it can still provide sufficient elastic restoring force when the thickness of the steel strip is reduced to 0.105mm.

[0030] like Figure 2-4As shown, a measuring tape includes a casing 1, a measuring wheel 2, a thin coil spring 3, a measuring tape 4, a spindle 5, and a center nail 6. The thin coil spring 3 is manufactured using the aforementioned process. The center nail 6 is fixedly connected to the casing 1 and is arranged along the central axis of the casing 1. The measuring wheel 2 is rotatably sleeved on the outside of the center nail 6. The spindle 5 is fixedly arranged inside the measuring wheel 2 and is coaxial with the center nail 6. The spindle 5 is used to enhance the structural stability of the measuring wheel 2 and prevent the measuring wheel 2 from shifting during rotation. The inner end of the thin coil spring 3 is snapped and fixed to the outer wall of the measuring wheel 2. Specifically, the two are firmly fixed by a pre-set slot on the outer wall of the measuring wheel 2 and a snap head on the inner end of the thin coil spring 3. The outer end of the thin coil spring 3 is connected by a hook (the outer end of the coil spring is stamped). The hook-shaped spring 3 hooks onto the inner wall of the ruler 4 and is fixed to the end of the ruler 4 to ensure that the ruler 4 can be wound synchronously with the thin coil spring 3, preventing the ruler 4 from falling off. One end of the ruler 4 is wound around the outer wall of the ruler wheel 2 and is linked with the ruler wheel 2 under the limiting action of the thin coil spring 3. The other end of the ruler 4 can extend to the outside of the ruler shell 1. The thin coil spring 3 is initially in a pre-tightened state. When the ruler 4 is pulled outward, the ruler 4 drives the thin coil spring 3 to unfold synchronously. The thin coil spring 3 accumulates elastic potential energy. After the ruler 4 is released, the thin coil spring 3 contracts under the action of elastic restoring force, driving the ruler wheel 2 to rotate in the opposite direction around the central nail 6, thereby driving the ruler 4 to wrap synchronously back around the outer wall of the ruler wheel 2, realizing the automatic recycling of the ruler 4.

[0031] like Figure 2-4 As shown, the ruler wheel 2 has an internal mounting cavity, in which the spindle 5 is fixedly embedded, enhancing the overall structural strength of the ruler wheel 2 and ensuring that it can rotate stably under the force of the thin coil spring 3 without easily deforming. The inner end of the thin coil spring 3 is fixed to the outer wall of the ruler wheel 2 by a snap-fit ​​engagement, ensuring a secure connection and facilitating installation and disassembly. The outer end of the thin coil spring 3 is hooked to the end of the ruler belt 4 via a hook, thus securing it to the ruler belt 4 and facilitating its replacement and maintenance.

[0032] like Figure 2-4 As shown, the ruler housing 1 is provided with an opening 7 for the ruler belt 4 to enter and exit, which is used to pull out or retract the ruler belt 4. The edges of the opening 7 are rounded to prevent the ruler belt 4 from being scratched when entering and exiting, thus extending the service life of the ruler belt 4.

[0033] like Figure 2-4 As shown, the ruler belt 4 and the outer wall of the ruler wheel 2 are fixed by a thin coil spring 3. The inner end of the thin coil spring 3 is engaged with the ruler wheel 2 and the outer end is attached to the ruler belt 4, so that the ruler belt 4 can keep synchronous linkage with the thin coil spring 3 and the ruler wheel 2 when winding, avoiding relative slippage between the ruler belt 4 and the ruler wheel 2, and ensuring that the ruler belt 4 is neatly wound and smoothly pulled out.

[0034] like Figure 2-4As shown, the ruler shell 1 is composed of two shell halves that are snapped together. The ruler shell 1 has screw holes, and the two shell halves are locked together by screws, which facilitates the installation, inspection and maintenance of the structure inside the ruler shell 1.

[0035] like Figure 2-4 As shown, the outer side of the ruler housing 1 is provided with a braking locking structure for locking the extension and retraction of the ruler belt. The improvement of the thin coil spring manufacturing process and the ruler in this embodiment is the preparation process of the thin coil spring and the assembly structure of the thin coil spring. The ruler belt locking structure adopts any existing structure, and the braking locking structure is a conventional technical means in the field, which will not be described in detail here.

[0036] The manufacturing process of a thin coil spring and the working principle of the measuring tape in this embodiment are as follows: First, the steel strip of the thin coil spring 3 is prepared. 65Mn steel strip is selected and processed according to the aforementioned continuous quenching and deep tempering process parameters. After completion, the hardness and metallographic structure of the steel strip are tested to ensure that the hardness reaches HV630 or higher and the residual austenite content in the microstructure is less than 5%. Next, key components are processed, such as the measuring tape shell 1, measuring wheel 2, thin coil spring 3, and measuring tape 4, etc., according to the determined dimensional parameters. The outer diameter of the measuring wheel is controlled within the range of 55-57.1mm, and the thickness of the thin coil spring 3 is controlled within 0.09-0.105mm. While the thin coil spring 3 is thinned, its strength also meets the requirements. For practical use, the thickness (including coating) of the measuring tape 4 is between 0.14-0.16mm. This allows the measuring tape 4 to be installed within a standard 5m measuring tape casing, with a length of up to 8 meters. For final assembly and testing, the processed components are assembled into a measuring tape. The measuring wheel 2 is fitted onto the outside of the center nail 6, and the inner end of the thin coil spring 3 is engaged in the groove on the outer wall of the measuring wheel 2. The outer end is hooked to the end of the measuring tape 4 via a hook. One end of the measuring tape 4 is wrapped around the outer wall of the measuring wheel 2, and the other end extends outward through the opening 7 of the measuring casing 1. Finally, the two halves of the measuring casing 1 are engaged and tightened with screws. The smoothness of the measuring tape being pulled out and retracted, as well as its straightness, are tested to ensure that all performance standards are met.

[0037] This embodiment describes a thin coil spring manufacturing process and a measuring tape. The thin coil spring 3, made from steel strip treated with continuous quenching and deep tempering process parameters, is assembled with other components to form a measuring tape. While the thin coil spring 3 is thinner, its strength still meets usage requirements, and it occupies less space. While maintaining the same external shape (casing 1) as the market-standard 5-meter measuring tape, it accommodates an 8-meter long measuring tape, breaking the industry's traditional perception of small-volume measuring tape capacity. This improves the space utilization rate within the casing 1 and allows for the insertion of measuring tapes with sufficient thickness. Simultaneously, the structural design of the thin coil spring 3, with the inner end engaging the measuring wheel 2 and the outer end hooking the measuring tape 4, ensures that the measuring tape 4 does not detach during winding. Combined with the elastic restoring force of the thin coil spring 3, it stably achieves the automatic retraction function of the measuring tape 4. The structure is reasonable and easy to use.

[0038] Finally, it should be noted that the above descriptions are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A manufacturing process for thin coil springs, characterized in that, Includes the following steps: S1 quenching treatment: Place the 65Mn thin steel strip of the set thickness on the continuous production line, convey it at a constant linear speed of 8 meters / minute, continuously heat it to 860℃ and keep it at a constant temperature for a preset time to make the steel strip structure completely austenitic. S2 cryogenic treatment: After the steel strip is quenched, it is quickly transferred to the cryogenic process, cooled to -90℃ and kept at a constant temperature to inhibit the precipitation of residual austenite and promote the complete transformation of residual austenite into martensite. S3 Tempering treatment: After deep cooling, the steel strip continues to be conveyed at a linear speed of 8 meters / minute and sent to the tempering process area. It is tempered at 370°C at a medium temperature to eliminate the residual stress inside the steel strip and obtain the steel strip for making thin coil springs (3). S4 Coiling and Forming Process: After the tempering process is completed, the steel strip cooled to room temperature is continuously coiled into a ring shape through a coiling and forming equipment, and then shaped and maintained to obtain the thin coil spring (3).

2. A measuring tape, characterized in that: The device includes a ruler housing (1), a ruler wheel (2), the thin coil spring (3), a ruler belt (4), a mandrel (5), and a center nail (6). The thin coil spring (3) is manufactured using the process described in claim 1. The center nail (6) is fixedly connected to the ruler housing (1). The ruler wheel (2) is rotatably sleeved on the outside of the center nail (6). The mandrel (5) is fixedly disposed inside the ruler wheel (2), and the mandrel (5) is coaxially arranged with the center nail (6). The inner end of the thin coil spring (3) is snapped and fixed to the outer wall of the ruler wheel (2), and the outer end of the thin coil spring (3) is hooked and fixed to the ruler belt (4). One end of the ruler belt (4) is wrapped around the outer wall of the ruler wheel (2) and is fixed synchronously with the thin coil spring (3). The other end of the ruler belt (4) can extend movably to the outside of the ruler housing (1).

3. A measuring tape according to claim 2, characterized in that: The measuring wheel (2) has an internal mounting cavity, and the mandrel (5) is fixedly embedded in the mounting cavity.

4. A measuring tape according to claim 2, characterized in that: The inner end of the thin coil spring (3) is fixed to the outer wall of the ruler wheel (2) by a slot, and the outer end of the thin coil spring (3) is hooked to the end of the ruler belt (4) to achieve fixation with the ruler belt (4).

5. A measuring tape according to claim 2, characterized in that: The ruler shell (1) is provided with an opening (7) for the ruler belt (4) to enter and exit.

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