Torsion detection clamp for torsional spring
By designing a torsion spring torque detection fixture including fixed components and movable components, the problem that existing tools are difficult to apply torsion springs in different structures is solved, and effective detection of one end axial outward folding torsion spring is achieved, which is efficient, economical and environmentally friendly.
Patent Information
- Application Number
- CN202510425999.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-04-07
- Publication Date
- 2025-06-24
AI Technical Summary
Existing torsion spring torque measurement tools are difficult to apply torsion springs of different structures, especially torsion springs with only one end axially outward folded.
A torsion spring torque detection fixture is designed, including a fixed assembly and a movable assembly. The fixing assembly restricts the torsion spring into the cavity and fixes its first end through the base plate, bearing, support block, fixing rod and pointer. The movable assembly drives the torsion spring to twist from the second end through the rotating shaft, lever, angle disc and digital torque wrench, and displays the torsion angle and torque value in real time.
This detection fixture can be effectively applied to torsion springs that fold outwardly at one end, so as to achieve batch detection of whether their torque is qualified, and has the characteristics of simple structure, easy use and low manufacturing cost.
Smart Images
Figure CN120194922A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of torsion measurement of torsion springs, and particularly to a torsion detection fixture for torsion springs. Background Art
[0002] Before the torsion spring is taken off the production line, it is necessary to randomly inspect the torsion of the torsion spring by using a torsion measurement tool to determine whether the torsion springs of this batch are qualified. Since the structures of torsion springs in different batches may be different, it is difficult to use the same torsion measurement tool to measure torsion springs with different structures.
[0003] For example, the utility model patent with the authorized publication number of CN206440412U discloses a torsion spring force measuring machine, which includes a fixed table, a sensor, a dial rod, a fixed shaft, a rotating table, a linkage turntable and a hand-cranked graduated turntable. A hand-cranked graduated turntable is provided on one side of the rotating table, and a linkage turntable is provided adjacent to the hand-cranked graduated turntable. A dial rod is fixedly provided on the surface layer of the linkage turntable. A fixed shaft is provided on one side of the dial rod, and a sensor is provided on one side of the fixed shaft. The sensor and the fixed shaft are both fixedly installed on the surface layer of the fixed table. A test torsion spring is sleeved on the fixed shaft. One end of the test torsion spring is slidably connected to the sensor, and the other end is slidably connected to the dial rod. Among them, the hand-cranked graduated turntable is in transmission connection with the linkage turntable 7. The torsion spring is sleeved on the fixed shaft, one end of the torsion spring is placed on the sensor, and the other end is placed on the dial rod of the linkage turntable. The hand-cranked graduated turntable is rotated to a unit angle, and the linkage turntable rotates to the same unit angle. During this period, the torsion spring is toggled to twist and deform, and the sensor detects the torsion spring pressure in real time and converts it into torque to complete the test. Through the above text description and in combination with the drawings of this patent, it can be seen that the torsion spring force measuring machine disclosed in this patent is only applicable to torsion springs with both ends folded outward relative to the spiral main axis.
[0004] While Figure 1 As another common torsion spring 30, this torsion spring 30 includes a spiral main body 31. A bent head 32 with a radially inward fold is provided at the first end of the spiral main body 31. A bent portion 33 with a radially inward fold is provided near the end of the second end of the spiral main body 31. The end of the bent portion 33 is folded outward relative to the spiral main body 1 axis. It can be seen that Figure 1 for the shown torsion spring 30, only one end is folded outward along the axis. Obviously, the torsion spring force measuring machine disclosed in the above patent is not applicable to it. Therefore, a special torsion measurement tool needs to be designed for this type of torsion spring 30. Summary of the Invention
[0005] The present invention aims to provide a torsion detection fixture for torsion springs, which is specifically used to detect the torsion of the torsion springs as Figure 1 shown.
[0006] For this purpose, the present invention adopts the following technical solutions:
[0007] Torsion spring torque detection fixture, including a set of fixed components and a set of movable components used in cooperation with the fixed components.
[0008] The fixed components include a base plate and a bearing, a support block, a fixed rod and a pointer provided on the base plate. The bearing is fixedly provided in the shaft hole provided on the top surface of the base plate. The support block includes more than three and is evenly arranged around the shaft hole on the base plate to form a limiting cavity on the top surface of the base plate for vertically placing the torsion spring and making the torsion spring stand upright on the base plate. The fixed rod is provided inside the limiting cavity for fixing the first end of the torsion spring. The pointer is radially arranged above the limiting cavity.
[0009] The movable components include a rotating shaft, a bushing sleeved and fixed on the rotating shaft, a rotating rod seat fixed on the bushing, a lever fixed at the bottom of the rotating rod seat, an angle disc fixed at the top of the rotating rod seat and sleeved on the rotating shaft through its central hole, and a digital display torque wrench fixed at the top of the rotating shaft. The rotating shaft is used to movably insert into the bearing from above. The lever is used to drive the torsion spring to twist from the second end. The angle disc is used to cooperate with the pointer to display the torsion angle of the torsion spring. The digital display torque wrench is used to drive the rotating shaft, the bushing, the rotating rod seat, the lever and the angle disc to rotate synchronously in the same direction and display the torque value after the torsion spring rotates.
[0010] In the present invention, a bearing, a limiting cavity, a fixed rod and a pointer are provided on a base plate, and a lever, an angle disc and a digital display torque wrench are provided on a rotating shaft. The limiting cavity can prevent the torsion spring from eccentric movement during torsion. The fixed rod can fix the first end of the torsion spring. The rotating shaft can movably dock with the bearing and drive the lever and the angle disc to rotate. The lever can drive the torsion spring to twist from the second end. The angle disc can cooperate with the pointer to display the torsion angle of the torsion spring. The digital display torque wrench can be used to drive the rotating shaft, the lever and the angle disc to rotate and display the torque value after the torsion spring twists. Its structure Figure 1 matches the described torsion spring and can be used to batch detect whether the torque of the torsion spring of this type of structure is qualified. In addition, the present invention also has the characteristics of simple structure, convenient use and low manufacturing cost. BRIEF DESCRIPTION OF THE DRAWINGS
[0011] Figure 1 Schematic diagram of the torsion spring structure applicable to the present invention;
[0012] Figure 2 Schematic diagram of the torsion spring torque detection fixture of the present invention;
[0013] Figure 3 Schematic diagram of the fixed components of the present invention;
[0014] Figure 4 Schematic diagram of the movable components of the present invention;
[0015] Figure 5 Schematic diagram of the use state of the fixed components of the present invention;
[0016] Figure 6 This is one of the schematic diagrams of the usage state of the torsion spring torque detection fixture of the present invention. The dotted arrow in this drawing indicates the torsion direction of the torsion spring;
[0017] Figure 7 This is the second schematic diagram of the usage state of the torsion spring torque detection fixture of the present invention;
[0018] Figure 8 This is a cross-sectional view of the usage state of the torsion spring torque detection fixture of the present invention.
[0019] In the figure, the markings are: 10, fixed component; 11, base plate, 11.1, shaft hole, 11.2, first screw hole, 11.3, straight blind groove, 11.31, second screw hole, 11.4, scale line; 12, bearing; 13, support block, 13.1, first straight long through hole; 14, fixed rod; 15, pointer; 16, first screw; 17, adjusting rod seat, 17.1, second straight long through hole; 18, second screw; 19, screw rod; 110, adjusting nut; 20, movable component; 21, rotating shaft, 21.1, convex key, 21.2, multi-angle stud; 22, bushing, 22.1, keyway, 22.2, plane, 22.21, third screw hole, 22.3, fourth screw hole; 23, rotating rod seat, 23.1, third straight long through hole, 23.2, fourth straight long through hole, 23.3, jack; 24, lever; 25, angle disc, 25.1, disc center hole, 25.2, arc through hole; 26, digital display torque wrench, 26.1, digital display torque meter, 26.2, handle, 26.3, connecting handle, 26.4, bushing; 30, torsion spring; 31, spiral main body; 32, bent head; 33, bent part. Detailed implementation manners
[0020] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments.
[0021] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments.
[0022] As Figure 2 and Figure 3 shown in the torsion spring torque detection fixture, which is specifically used to detect the torsion spring 30 as Figure 1 shown. This fixture includes a set of fixed components 10, and the fixed components 10 include a base plate 11, a bearing 12, a support block 13, a fixed rod 14, and a pointer 15, wherein:
[0023] AsFigure 2-3 As shown, the bottom plate 11 is a rectangular plate, and a shaft hole 11.1 that communicates from top to bottom is provided at the exact center thereof. A bearing 12 is fixedly provided at the lower part of the shaft hole 11.1.
[0024] As Figure 2-3 As shown, there are four support blocks 13. The four support blocks 13 are evenly arranged in a ring on the top surface of the bottom plate 11 around the shaft hole 11.1 to enclose a limiting cavity on the top surface of the bottom plate 11 that can vertically accommodate the torsion spring 30 and make the torsion spring 30 stand upright on the bottom plate 11. To prevent the torsion spring 30 from undergoing eccentric movement during torsion, the height of all support blocks 13 is not lower than the height of the torsion spring 30 and they are all located at positions that lightly touch the torsion spring 30 or are located adjacent to the torsion spring 30. The four support blocks 13 are all identical rectangular blocks and their length directions are all arranged radially with respect to the shaft hole 11.1. A first linear long through hole 13.1 that communicates from top to bottom is provided on each support block 13 radially with respect to the shaft hole 11.1. A first screw 16 is provided in the first linear long through hole 13.1, and the first screw 16 is screwed into a first screw hole 11.2 provided correspondingly on the top surface of the bottom plate 11 to lock the support block 13 on the bottom plate 11 and enable the support block 13 to be radially adjusted to a suitable position according to the size of the torsion spring 30. Scale lines 11.4 are provided radially on the top surface of the bottom plate 11 beside each support block 13 with respect to the shaft hole 11.1. To make the size of the limiting cavity match the size of the torsion spring 30, before detecting a certain batch of torsion springs 30, the positions of the support blocks 13 can be accurately radially adjusted with reference to the scale lines 11.4 so that the inner ends of the support blocks 13 are on the same circumference.
[0025] As Figure 2-3 As shown, a linear blind groove 11.3 is provided radially on the top surface of the bottom plate 11 around the shaft hole 11.1. The linear blind groove 11.3 is arranged along the midpoint connection line of the short sides of the bottom plate 11 and penetrates the upper part of the shaft hole 11.1 and one short side of the bottom plate 11. An adjusting rod seat 17 is provided in the linear blind groove 11.3. A fixing rod 14 stands upright and is fixed to the top of the inner end of the adjusting rod seat 17 and is located inside the limiting cavity to be used for hanging the bent head 32 of the first end of the torsion spring 30 from the inside. A second linear long through hole 17.1 that communicates from top to bottom is provided on the adjusting rod seat 17 along the length direction of the linear blind groove 11.3. A second screw 18 is provided in the second linear long through hole 11.3, and the second screw 18 is screwed into a second screw hole 11.31 provided at the bottom of the linear blind groove 11.3 to lock the adjusting rod seat 17 on the bottom plate 11 and enable the adjusting rod seat 17 and the fixing rod 14 to be radially adjusted to a position where they can hang the bent head 32 of the first end of the torsion spring 30 according to the size of the torsion spring 30.
[0026] As Figure 2-3As shown, on the top surface of the bottom plate 11 outside the limiting cavity, a screw rod 19 is vertically provided. Two adjusting nuts 110 are screwed on the screw rod 19. Between the two adjusting nuts 110, a pointer 15 is provided. The pointer 15 is movably sleeved on the screw rod 19 between the two adjusting nuts 110 through a rod sleeve provided at the tail of its needle. The two adjusting nuts 110 lock and fix the tail of the needle of the pointer 15 on the screw rod 19, so as to radially arrange the pointer 15 above the limiting cavity and make the height of the pointer 15 adjustable.
[0027] In addition, as Figure 2 shown, in order to facilitate the taking of the entire fixing assembly 10, a handle 111 can be provided on the top surface of the bottom plate 11.
[0028] As Figure 2 and 4 shown, the fixture further includes a set of movable components 20 that cooperate with the fixing assembly 10 and are used to drive the torsion spring 30 to twist from the second end and display the torsion value after the torsion spring 30 twists. The movable components 20 include a rotating shaft 21, a bushing 22 sleeved and fixed on the rotating shaft 21, a rotating rod seat 23 fixed on the bushing 22, a dial rod 24 fixed at the bottom of the rotating rod seat 23, an angle disc 25 fixed at the top of the rotating rod seat 23 and sleeved on the rotating shaft 21 through its central hole 25.1, and a digital display torque wrench 26 fixed at the top of the rotating shaft 21, where:
[0029] As Figure 2-4 shown, a number of convex keys 21.1 are circumferentially arranged on the outer wall of the near-bottom of the rotating shaft 21. The bushing 22 is movably sleeved on the rotating shaft 21 from the top and is fixedly butted with the convex keys 21.1 through a number of key grooves 22.1 correspondingly provided at its bottom end. The top end of the rotating shaft 21 exposes above the bushing 22 and the angle disc 25.
[0030] As Figure 2-4As shown, on the corresponding two sides at the top of the bushing 22, there are parallel planes 22.2, and on both sides of the plane 22.2, there are third screw holes 22.21. On the rotating rod base 23, there is a third linear long through hole 23.1 that communicates from top to bottom, and on its corresponding two sides, there are fourth linear long through holes 23.2 that communicate with the third linear long through hole 23.1. The rotating rod base 23 is sleeved on the top of the bushing 22 through its third linear long through hole 23.1, and the two long faces of its third linear long through hole 23.1 respectively clamp the two planes 22.2. In the fourth linear long through holes 23.2 on both sides, there are third screws 27, and the third screws 27 on both sides are respectively screwed into the third screw holes 22.21 on their respective same sides to jointly lock the rotating rod base 23 on the bushing 22. Along the short side direction at the top of the rotating rod base 22, there are multiple jacks 23.3, and the top end of the lever 24 is inserted and fixed in any one of the jacks 23.3, so as to be vertically fixed at the bottom of the bushing 22 for hanging and connecting the bent part 33 of the second end of the torsion spring 30 from the inside. During use, the position of the rotating rod base 23 can be adjusted horizontally to adjust the lever 24 to the position for hanging and connecting the second end of the torsion spring 30.
[0031] As Figure 2-4 shown, the angle disc 25 is horizontally arranged on the top of the bushing 22, and on its top surface, there is an angle scale around its disc center hole 25.1. The tip of the pointer 15 is located above the angle disc 25 and radially points to the angle scale. On the disc surface of the angle disc 25, there are more than two arc through holes 25.2 around its disc center hole 25.1. In each arc through hole 25.2, there is a fourth screw 28, and each fourth screw 28 is screwed into the fourth screw hole 22.3 correspondingly arranged on the top surface of the bushing 22 to lock and fix the angle disc 25 on the bushing 22. During installation, the angle disc 25 can be adjusted circumferentially to align the pointer 15 in the initial state with its zero scale line.
[0032] As Figure 2-4 shown, the digital display torque wrench 26 includes a digital display torque meter 26.1. The digital display torque meter 26.1 is rectangular, and its corresponding two sides are respectively set as the driving end and the input end. A handle 26.2 is fixedly arranged at its driving end, and a connector 26.3 is fixedly arranged at its input end. The handle 26.2, the digital display torque meter 26.1, and the connector 26.3 are coaxially arranged. A sleeve 26.4 is radially fixed on the connector 26.3, and the sleeve 26.4 is sleeved and locked on the shaft head 21.2 arranged at the top end of the rotating shaft 21 to fixedly connect the digital display torque wrench 26 and the rotating shaft 21 as a whole, and make the digital display torque wrench 26 and the rotating shaft 21 perpendicular to each other.
[0033] As Figure 1 and 5As shown, when detecting the torsion spring 30, the torsion spring 30 can be first placed in the limiting cavity on the bottom plate 11 with the first end at the bottom and the second end at the top, and the bent head 32 at the first end of the torsion spring 30 can be hooked on the fixing rod 14 from the inside. The torsion spring 30 can freely fall on the bottom plate 11 by its own gravity, and the four support blocks 13 together will keep the helical body 31 of the torsion spring 30 in a vertical state from the outside. After that, as Figure 6-8 shown, hold the handle 26.2 and pick up the entire movable assembly 20, movably dock the rotating shaft 21 with the bearing 12 from above, and hook the lever 25 on the bent portion 33 at the second end of the torsion spring 30 from the inside. Drive the digital display torque wrench 26 to rotate in the horizontal direction through the handle 26.3 to drive the rotating shaft 21, the shaft sleeve 22, the rotating rod seat 23, the lever 24 and the angle disc 25 to rotate synchronously in the same direction. When the lever 24 rotates, it can drive the torsion spring 30 to twist starting from the second end. The pointer 15 and the angle disc 25 can cooperate to display the twisting angle. The torque after the torsion spring 30 is twisted can be sequentially conducted to the digital display torque meter 26.1 through the lever 24, the rotating rod seat 23, the shaft sleeve 22, the rotating shaft 21, the sleeve 26.4 and the connector 26.3, and the digital display torque meter 26.1 will display its torque value. Twist all the torsion springs 30 by the same angle, and it can be judged whether the torque of each torsion spring 30 is within the qualified numerical range.
[0034] For those skilled in the art, it is obvious that the present invention is not limited to the details of the above exemplary embodiments, and without departing from the spirit or basic characteristics of the present invention, the present invention can be implemented in other specific forms. Therefore, from any point of view, the embodiments should be regarded as exemplary and non-limiting. The scope of the present invention is defined by the appended claims rather than the above description. Therefore, all changes falling within the meaning and scope of the equivalent elements of the claims are intended to be included in the present invention. Any reference signs in the claims should not be regarded as limiting the claimed rights.
Claims
1. Torsion spring torque detection fixture, characterized by: It comprises a set of fixed components (10) and a set of movable components (20) used in conjunction with the fixed components (10); The fixing assembly (10) comprises a base plate (11) and a bearing (12), a support block (13), a fixing rod (14) and a pointer (15) arranged on the base plate (11); the bearing (12) is fixedly arranged in an axial hole (11.1) arranged on the top surface of the base plate (11); the support block (13) comprises more than three axial holes evenly arranged on the base plate (11) around the outer periphery of the axial hole (12) so as to enclose a limiting cavity on the top surface of the base plate (11) for vertically placing a torsion spring and making the torsion spring stand upright on the base plate (11); the fixing rod (14) is arranged inside the limiting cavity for fixing the first end of the torsion spring; and the pointer (15) is radially arranged above the limiting cavity; The movable assembly (20) comprises a rotating shaft (21), a shaft sleeve (22) sleeved and fixed on the rotating shaft (21), a rotating rod seat (23) fixed on the shaft sleeve (22), a lever (24) fixed at the bottom of the rotating rod seat (23), an angle disc (25) fixed at the top of the rotating rod seat (23) and sleeved on the rotating shaft (21) through its disc center hole (25.1), and a digital torque wrench (26) fixed at the top of the rotating shaft (21). The rotating shaft (21) is used to be movably inserted into the bearing (12) from the top, the lever (24) is used to drive the torsion spring to twist from the second end, the angle disc (25) is used to cooperate with the pointer (15) to display the torsion angle of the torsion spring, and the digital torque wrench (26) is used to drive the rotating shaft (21), the shaft sleeve (22), the rotating rod seat (23), the lever (24) and the angle disc (25) to rotate synchronously in the same direction and display the torque value of the torsion spring after rotation.
2. The torsion spring torque detection fixture according to claim 1, characterized in that: The height of the support block (13) is not less than the height of the torsion spring and is located at a position lightly touching the torsion spring, or at a position close to the torsion spring.
3. The torsion spring torque detection fixture according to claim 1 or 2, characterized in that: The support block (13) is fixed to the base plate (11) by a first screw (16); a first straight long hole (13.1) is provided on the support block (13) in a radial direction relative to the axial hole (11.1) and is communicated with the top and bottom; the first screw (16) passes through the first straight long hole (13.1) and is screwed to a first screw hole (11.2) correspondingly provided on the top surface of the base plate (11) to lock the support block (13) on the base plate (11); and a scale mark (11.4) is provided on the top surface of the base plate (11) next to each support block (13) in a radial direction relative to the axial hole (11.1).
4. The torsion spring torque detection fixture according to claim 1, characterized in that: The shaft hole (11.1) is a through hole, the bearing (12) is fixedly arranged at the lower part of the shaft hole (11.1), the top surface of the bottom plate (11) outside the shaft hole (11.1) is radially provided with a straight blind groove (11.3) penetrating the upper part of the shaft hole (11.1), the straight blind groove (11.3) is fixedly provided with an adjusting rod seat (17), and the fixing rod (14) is uprightly fixed at the inner end top of the adjusting rod seat (17).
5. The torsion spring torque detection fixture according to claim 4, characterized in that: The adjusting rod seat (17) is fixed in the linear blind groove (11.3) by a second screw (18); a second linear long through hole (17.1) communicating with the top and the bottom is provided on the adjusting rod seat (17) along the length direction of the linear blind groove (11.3); the second screw (18) passes through the second linear long hole (13.1) and is screwed into a second screw hole (11.31) provided at the bottom of the linear blind groove (11.3), so as to lock the adjusting rod seat (17) on the bottom plate (11) of the linear blind groove (11.3).
6. The torsion spring torque detection fixture according to claim 1, 2, 4 or 5, characterized in that: A screw rod (19) is vertically provided on the top surface of the bottom plate (11) outside the limiting cavity, and two adjusting nuts (110) are screwed on the screw rod (19). The pointer (15) is movably sleeved on the screw rod (19) between the two adjusting nuts (110) through a rod sleeve provided at the needle tail, so as to be locked and fixed on the screw rod (19) by the two adjusting nuts (110).
7. The torsion spring torque detection fixture according to claim 1, characterized in that: A plurality of convex keys (21.1) are circumferentially arranged on the outer wall near the bottom of the rotating shaft (21); the shaft sleeve (22) is movably inserted into the rotating shaft (21) from the top and is fixedly connected to the convex keys (21.1) one by one through a plurality of key slots (22.1) correspondingly arranged at the bottom end thereof.
8. The torsion spring torque detection fixture according to claim 1, characterized in that: The top of the shaft sleeve (22) is provided with planes (22.2) parallel to each other on the corresponding two sides, and the planes (22.2) on both sides are provided with third screw holes (22.21); the rotating rod seat (23) is provided with a third straight long through hole (23.1) communicating with the top and bottom, and the corresponding two sides are provided with fourth straight long through holes (23.2) communicating with the third straight long through hole (23.1); the rotating rod seat (23) is sleeved on the top of the shaft sleeve (22) through its third straight long through hole (23.1) and clamps the two planes (22.2) respectively through the two long faces of its third straight long through hole (23.1); the fourth straight long through holes (23.2) on both sides are provided with third screws (27); the third screw holes (27) on both sides are respectively screwed with the third screw holes (22.21) on the same side, and the rotating rod seat (23) is locked on the shaft sleeve (22) together.
9. The torsion spring torque detection fixture according to claim 8, characterized in that: The angle disc (25) is horizontally arranged on the top of the shaft sleeve (22) and an angle meter is arranged on the top surface thereof around the disc center hole (25.1). The needle tip of the pointer (15) is located above the angle disc (25) and radially points to the angle meter. Two or more arc-shaped through holes (25.2) are arranged on the disc surface of the angle disc (25) around the disc center hole (25.1). A fourth screw (28) is arranged in each arc-shaped through hole (25.2). Each fourth screw (28) is screwed into a fourth screw hole (22.3) correspondingly arranged on the top surface of the shaft sleeve (22) to lock and fix the angle disc (25) on the shaft sleeve (22).
10. The torsion spring torque detection fixture according to any one of claims 1, 7 to 9, characterized in that: The top of the rotating shaft (21) is exposed above the angle disc (25) and a shaft head (21.2) is arranged on the top of the rotating shaft (21). The digital torque wrench (26) comprises a digital torque gauge (26.1), a handle (26.2) and a connector (26.3) coaxially arranged on the corresponding two sides of the digital torque gauge (26.1). A shaft sleeve (26.4) is radially arranged on the connector (26.3), and the shaft sleeve (26.4) is sleeved and locked on the shaft head (21.2).
Citation Information
Patent Citations
Torsional spring force measuring machine
CN206440412U