Engine recoil starter pull cord boot machining fixture
Patent Information
- Application Number
- CN202522506724.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-11-26
- Publication Date
- 2026-10-27
- Estimated Expiration
- 2035-11-26
AI Technical Summary
由于护套坯料本身较小，且为钣金冲压件，其形状较为特殊(为蘑菇形状)；夹持时很难夹稳，为保证护套坯料的轴线与三爪夹同轴还需要多次夹持或调整；从而导致护套的车加工效率较低，且操作较为繁杂
[0006]本实用新型发动机反冲启动器拉绳护套车加工夹具的有益技术效果是能够方便的对护套坯料进行夹持，且能够保证护套坯料的轴线与转轴同轴；有效的简化了操作，提高了加工效率。
Smart Images
Figure CN224896560U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the machining technology of engine recoil starter pull rope sheath, and in particular to a machining fixture for engine recoil starter pull rope sheath. Background Technology
[0002] The recoil starter is a key component of small gasoline and diesel engines. Its function is to rapidly rotate the engine's flywheel by quickly pulling the starter's cable. This rapid rotation causes the compression ratio in the engine cylinders to reach the diesel fuel's knock-off point, resulting in combustion and enabling the engine to operate normally. Typically, a cover is installed in the recoil starter, with the cable leading out through a through-hole on the side of the cover. Because the recoil starter contains a coil spring, a pulley, and the cable, pulling the cable requires considerable force, and after the engine starts, the cable quickly winds around the pulley under the action of the coil spring. If the edge of the through-hole on the side of the cover is thin or sharp, it may damage the cable. To protect the cable, a protective sleeve is usually riveted to the through-hole on the side of the cover, making the edge of the through-hole rounded, thus protecting the cable as it enters and exits the cover. The sheath is mushroom-shaped, including a head and a stem, and is formed by stamping a thin sheet metal. A through hole is provided in the stem of the sheath. After inserting the sheath stem into the through hole on the side of the cover, the end of the sheath stem is then stamped outwards and flipped to rivet it onto the through hole on the side of the cover (see Appendix). Figure 1 In the diagram, a represents the cover body, and b represents the sheath. The sheath is formed by stamping a thin sheet metal. When punching through the hole in the sheath, the edge of the hole usually forms a serrated shape. To prevent the serrated edge of the sheath's through hole from damaging the pull rope and to ensure the quality of the sheath's riveting, the serrated edge of the sheath's through hole needs to be removed (see Appendix). Figure 2 The sheath with its serrated edges not removed is usually referred to as the "sheath blank". Current technology typically uses machining to remove the serrated edges of the through-hole in the sheath blank, clamping the head of the blank in a three-jaw chuck during machining. Because the sheath blank itself is small and is a sheet metal stamping part with a rather unique shape (mushroom-shaped), it is difficult to clamp securely. Multiple clamping or adjustments are required to ensure the axis of the sheath blank is coaxial with the three-jaw chuck, resulting in low machining efficiency and complex operation. Summary of the Invention
[0003] To address the above problems, this utility model proposes a machining fixture for an engine recoil starter pull rope sheath.
[0004] This utility model relates to a machining fixture for an engine recoil starter pull rope sleeve, comprising: a turntable, an outer sleeve, an inner core, an expansion sleeve, a pull sleeve, a spring, a pull rod, a push plate, and a cylinder; the turntable has four through holes evenly distributed around its circumference; the outer sleeve is cylindrical and fixed to the turntable; the pull sleeve is slidably installed inside the outer sleeve, and has an inner inclined cylindrical surface that is smaller at the top and larger at the bottom above its inner circle; the expansion sleeve is fixedly installed inside the pull sleeve, and has an outer inclined cylindrical surface that matches the inner inclined cylindrical surface of the pull sleeve above its outer circle; the inner circle of the expansion sleeve has two steps, one large and one small, with the diameter of the larger upper step being smaller than that of the pull sleeve. The outer diameter of the blank head is large, and four notches are evenly distributed on the upper circumference of the expansion sleeve; the inner core is a cylinder with three steps: large, medium, and small. The outer diameter of the large step is smaller than that of the large step in the inner circle of the expansion sleeve, and the medium step is slidably installed inside the small step in the inner circle of the expansion sleeve; the spring sleeve is fitted outside the small step of the inner core; there are four pull rods, the front ends of which pass through the through holes of the turntable and are fixed to the bottom of the pull sleeve; the push plate is a circular plate and is fixed to the rear end of the four pull rods; the piston of the cylinder points to the push plate and is fixed in the inner cavity of the four pull rods, and the bottom of the cylinder is fixed to the turntable.
[0005] Furthermore, the distance from the bottom surface of the small step of the inner core to the surface of the turntable is greater than twice the thickness of the head of the sheath blank.
[0006] The beneficial technical effect of this utility model engine recoil starter pull rope sheath machining fixture is that it can conveniently clamp the sheath blank and ensure that the axis of the sheath blank is coaxial with the rotating shaft; it effectively simplifies the operation and improves the processing efficiency. Attached Figure Description
[0007] Appendix Figure 1 A three-dimensional schematic diagram of the sheath riveted to the front and back of the cover;
[0008] Appendix Figure 2 A 3D schematic diagram of the sheath blank before and after machining;
[0009] Appendix Figure 3 This is a three-dimensional schematic diagram of the machining fixture for the engine recoil starter pull rope sheath of this utility model;
[0010] Appendix Figure 4 This is an exploded three-dimensional schematic diagram of the machining fixture for the engine recoil starter pull rope sheath of this utility model;
[0011] Appendix Figure 5 This is a cross-sectional schematic diagram of the machining fixture for the engine recoil starter pull rope sheath of this utility model;
[0012] Appendix Figure 6 This is a cross-sectional view of the sheath blank before clamping.
[0013] Appendix Figure 7This is a cross-sectional view of the sheath blank after it has been clamped.
[0014] In the diagram, 1 is the turntable, 2 is the outer casing, 3 is the inner core, 4 is the expansion sleeve, 5 is the pull sleeve, 6 is the spring, 7 is the pull rod, 8 is the push plate, 9 is the cylinder, a is the cover, and b is the protective sleeve.
[0015] The following description, in conjunction with the accompanying drawings and specific embodiments, further illustrates the machining fixture for the engine recoil starter pull rope sheath of this utility model. Detailed Implementation
[0016] See appendix Figure 3 , 4 5. As shown in the figure, the machining fixture for the engine recoil starter pull rope sleeve of this utility model includes: a turntable 1, an outer sleeve 2, an inner core 3, an expansion sleeve 4, a pull sleeve 5, a spring 6, a pull rod 7, a push plate 8, and a cylinder 9; the turntable has four through holes evenly distributed around its circumference; the outer sleeve is cylindrical and fixed on the turntable; the pull sleeve is slidably installed inside the outer sleeve, and an inner inclined cylindrical surface with a smaller upper part and a larger lower part is provided above its inner circle; the expansion sleeve is fixedly installed inside the pull sleeve, and an outer inclined cylindrical surface matching the inner inclined cylindrical surface of the pull sleeve is provided above its outer circle; the inner circle of the expansion sleeve has two steps, one large and one small, on which... The diameter of the large step is larger than the outer diameter of the head of the sheath blank, and four notches are evenly distributed on the upper circumference of the expansion sleeve; the inner core is a cylinder with three steps: large, medium, and small. The outer diameter of the large step is smaller than that of the large step in the inner circle of the expansion sleeve, and the medium step is slidably installed inside the small step in the inner circle of the expansion sleeve; the spring sleeve is fitted outside the small step of the inner core; there are four pull rods, the front ends of which pass through the through holes of the turntable and are fixed to the bottom of the pull sleeve; the push plate is a circular plate and is fixed to the rear end of the four pull rods; the piston of the cylinder points to the push plate and is fixed inside the four pull rods, and the bottom of the cylinder is fixed to the turntable. This utility model of an engine recoil starter pull rope sheath machining fixture uses an expansion sleeve to clamp the sheath blank and also provides a sheath blank ejection function. In practical use, the machining fixture of this utility model is coaxially fixed or clamped to the lathe spindle via a turntable or outer sleeve. The head of the sheath blank is placed on the inner core surface manually or by a robotic arm, and the sheath blank is pushed towards the turntable. Under the action of the thrust, the inner core compresses the spring and moves towards the turntable, allowing the head of the sheath blank to fully enter the expansion sleeve. The cylinder is activated, and the cylinder piston pushes the push plate away from the turntable, while the pull rod drives the pull sleeve towards the turntable. The inner inclined cylindrical surface at the upper part of the inner circle of the pull sleeve forms a compression against the outer inclined cylindrical surface at the upper part of the outer circle of the expansion sleeve. Because the upper part of the expansion sleeve has four notches, the upper part of the expansion sleeve forms a circumferential clamping around the head of the sheath blank (see appendix). Figure 6 , 7Because this machining fixture is coaxial with the lathe spindle, the sheath blank it holds can also be coaxial with the lathe spindle. After machining, the cylinder is activated again, the cylinder piston moves to the turntable side, the pull sleeve releases its pressure on the expansion sleeve, and the expansion sleeve releases its grip on the sheath blank; the inner core moves outward rapidly under the action of the spring, pushing the machined sheath away from the expansion sleeve, thereby realizing the unloading of the sheath blank. This machining fixture uses an expansion sleeve to hold the sheath blank, which not only simplifies the operation but also ensures the clamping accuracy; it effectively simplifies the operation and improves the machining efficiency.
[0017] As one of the preferred technical solutions, the distance from the bottom surface of the small step of the inner core to the surface of the turntable is greater than twice the thickness of the head of the sheath blank. As mentioned earlier, the inner core moves towards one side of the turntable under the action of the thrust, so that the head of the sheath blank is completely inserted into the expansion sleeve. Setting the distance from the bottom surface of the small step of the inner core to the surface of the turntable to be greater than twice the thickness of the head of the sheath blank is to ensure that the inner core has sufficient movement distance, so that it can continue to move after ensuring that the head of the sheath blank is completely inserted into the expansion sleeve, and that there is still enough space after the head of the sheath blank is inserted into the expansion sleeve, so as to ensure that the sheath blank will not fall out of the expansion sleeve when clamped by the expansion sleeve.
[0018] Obviously, the beneficial technical effect of the engine recoil starter pull rope sheath machining fixture of this utility model is that it can conveniently clamp the sheath blank and ensure that the axis of the sheath blank is coaxial with the rotating shaft; it effectively simplifies the operation and improves the processing efficiency.
Claims
1. A machining fixture for an engine recoil starter pull rope sheath, characterized in that, The machining fixture includes: a turntable, an outer sleeve, an inner core, an expansion sleeve, a pull sleeve, a spring, a pull rod, a push plate, and a cylinder; the turntable has four through holes evenly distributed around its circumference; the outer sleeve is cylindrical and fixed to the turntable; the pull sleeve is slidably installed inside the outer sleeve, and has an inner inclined cylindrical surface that is smaller at the top and larger at the bottom above its inner circle; the expansion sleeve is fixedly installed inside the pull sleeve, and has an outer inclined cylindrical surface that matches the inner inclined cylindrical surface of the pull sleeve above its outer circle; the inner circle of the expansion sleeve has two steps, one large and one small, with the diameter of the upper large step being larger than the outer diameter of the head of the sleeve blank. The expansion sleeve has four notches evenly distributed around its upper circumference; the inner core is a cylinder with three steps: large, medium, and small. The outer diameter of the large step is smaller than that of the large step on the inner circle of the expansion sleeve, and the medium step is slidably installed inside the small step on the inner circle of the expansion sleeve; the spring sleeve is fitted outside the small step of the inner core; there are four pull rods, the front ends of which pass through the through holes of the turntable and are fixed to the bottom of the pull sleeve; the push plate is a circular plate and is fixed to the rear end of the four pull rods; the piston of the cylinder points to the push plate and is fixed inside the four pull rods, and the bottom of the cylinder is fixed to the turntable.
2. The machining fixture for the engine recoil starter pull rope sheath according to claim 1, characterized in that, The distance from the bottom surface of the small step of the inner core to the surface of the turntable is greater than twice the thickness of the head of the sheath blank.