WO1999040331A1 - Screw tightening tool - Google Patents

Abstract

A screw tightening tool which comprises a spiral-shaped power spring (1) and latch means (2). Mounted to a front end of the power spring (1) is an engagement member (3), which has a fitting portion (31) and is adapted to engage with a member being tightened. Provided on a rear end of the power spring (1) are a ring-shaped portion (41) and a fixture member (42), the ring-shaped portion (41) being fixed to a member, to which a member (H) being tightened, such as bolt and nut is mounted. The latch means (2) comprises a cord-shaped latch member (21), and a latch member insertion hole (22) provided on the power spring (1). The power spring (1) can be latched by inserting the latch member (21) through the latch member insertion hole (22) to wind the same around an outer periphery of the power spring (1), and latching of the latch member (21) is released by an operation, in which the ring-shaped portion (41) at the rear end of the power spring (1) is fixed to the member being mounted. Accordingly, it is possible to perform tightening with a predetermined torque without performing an operation of tightening a bolt, nut or the like with a predetermined torque.

Description

Technical field of screw fasteners

 The present invention relates to an improvement in a screw tightening tool for tightening a bolt, a nut, or the like by the winding elasticity of a mainspring.

 Light

 Fine bolts and nuts are widely used for fixing various members including buildings and railways, and the bolts and nuts are fixed to prevent loosening later. It is necessary to tighten with the tightening torque.

 However, it is necessary to use a torque wrench to tighten the bolts and nuts individually with a fixed tightening torque, and if it is necessary to tighten the bolts and nuts with a large tightening torque, labor is required for the operator.

 Also, for example, when bolts and nuts are used for wood, even if the bolts and nuts are finally tightened with a certain tightening torque, the bolts and nuts naturally become loose due to aging of the wood. For this reason, after the period has elapsed since the tightening, the tightening work must be performed again.

 The present invention has been proposed in view of the above circumstances, and can naturally tighten a bolt or a nut with a constant tightening torque without performing a tightening operation with a constant tightening torque. Provide a screw fastener that can maintain a constant tightening torque at all times even when used on wood, etc., where bolts and nuts naturally loosen due to aging. Is the first purpose.

A second object of the present invention is to provide a screw fastener that can easily release a locking member that locks a mainspring spring in an elastic state and that is easy to work. Disclosure of the invention

 The present invention solves the above problem by providing a screw fastener having the following features.

 The screw tightening device of the first invention of the present application includes a mainspring spring 1 having winding elasticity, and a locking means 2 which locks the mainspring 1 in a state of winding elasticity.

 A radially inner end of the mainspring 1 is engaged with a member H to be tightened such as a bolt. On the other hand, the rear end side of the mainspring spring 1 on the radially outer side is fixed to the workpiece S on which the workpiece H is mounted.

 The locking means 2 is made of a material that can be released.

 The screw fastener according to the second invention of the present application is provided with an engagement means 3 at a radially inner end portion of the mainspring panel 1 for non-rotatably engaging with a tightened member H such as a bolt or a nut. The rear end of the mainspring spring 1 on the radially outer side is provided with fixing means 4 for fixing the member H to be mounted to the material S to be mounted. In the screw tightening device of the third invention of the present application, the locking means 2 includes a string-shaped locking member 21 and a lock release mechanism for releasing locking of the locking member 21.

 The locking member 21 is wound around the outer periphery of the mainspring having a winding elasticity so that the mainspring 1 is locked with the winding elasticity.

 The lock release mechanism releases the lock of the lock member 21 when the rear end of the mainspring 1 is fixed to the workpiece S.

In the first and second inventions of the present application configured as described above, if the locking member 21 is released, the mainspring panel 1 locked up to that point is released and expanded by the winding elasticity. During this expansion, the member to be tightened H such as a bolt H 1 nut engaged with the front end of the mainspring 1 can be rotated, and can be tightened with a constant torque. At this time, for example, when the mainspring 1 is placed in the case, the mainspring 1 cannot be expanded beyond the inner diameter of the case. As a result, if the bolt HI is not tightened to the wood S in advance with a certain tightening torque There is a possibility that the tightening torque may not be achieved. However, in the present invention, after the locking member 21 is unlocked, there is no such thing as a case, and the mainspring spring is not provided.

There is nothing obstructing the expansion of 1, so the bolt H1 can be turned more

Even if the bolt H1 is attached to the wood S by hand, the bolt H1 can be rotated and tightened until a predetermined tightening torque is obtained. Therefore, even if a tool such as a spanner is not used, it is sufficient to simply set the bolt H1 on the wood S by hand and the operation can be easily performed.

 Further, after the bolt H1 is tightened, the bolt H1 can be maintained in a biased state by applying the elastic force of the spring 1 to the bolt H1. Therefore, after a while, © wood S as a material to be attached changes its diameter and bolts! When the tightening torque of (1) starts to decrease, the bolt H1 can be automatically tightened by the elastic force of the mainspring spring 1 in accordance with that, and a constant tightening torque can be maintained at all times.

 On the other hand, since the spring 1 having elasticity is merely locked by the locking member 21, the overall weight can be reduced as much as possible, and the labor for transportation and handling can be reduced. In addition, since a case for housing the mainspring 1 is not provided in the production, the processing can be simplified, and the mold can be produced at low cost with almost no need for a mold.

 In the third invention of the present application, the locking means 2 includes a string-shaped locking member 21 and a locking member.

21.A lock release mechanism that releases the lock of 1 is provided.The lock release mechanism locks the lock member 21 when the rear end of the mainspring 1 is fixed to the workpiece S. Shall be cancelled. By doing so, the locking of the locking member 21 can be released at the same time by one operation of fixing the rear end of the mainspring 1 to the material S to be mounted, and the operation can be facilitated. BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 (/) is a plan view of an embodiment of the screw fastener of the present invention, and FIG. 1 (B) is a side view thereof. FIG. 2 is a cross-sectional view taken along the line 第 in FIG. 1 (A).

 FIG. 3 is a plan view showing a state where the member to be tightened is tightened.

 FIG. 4 is a side view in which a part of the tightened state of the member to be tightened is shown in cross section. FIG. 5 is a side view showing another embodiment of the locking means.

 FIG. 6 (Α) is a plan view showing still another embodiment of the locking means, and FIG. 6 (Β) is a side view thereof.

 FIG. 7 is a plan view showing still another embodiment of the locking means. FIG. 8 (Α) is a plan view showing an embodiment using a U-shaped locking member as locking means, and FIG. 8 (Β) is a side view thereof.

 FIG. 9 is a plan view showing another embodiment of the engagement means.

 FIG. 10 (Α) is a plan view showing still another embodiment of the engaging means, and FIG. 10 (Β) is

FIG. 4 is a plan view of a mainspring having a tightened member attached to a rear end. BEST MODE FOR CARRYING OUT THE INVENTION

 Hereinafter, embodiments of the present invention will be specifically described with reference to the drawings.

 FIG. 1 (Α) is a plan view of a screw fastener according to an embodiment of the present invention, FIG. 1 (Β) is a side view thereof, and FIG. 2 is a II-II line of FIG. 1 (Α). It is sectional drawing.

 The screw tightening tool of the present invention includes a mainspring 1 and locking means 2. The mainspring 1 is formed by winding a long steel sheet in order from the front end side, arranging the front end side on the inside of the diameter, and arranging the rear end side on the inside of the diameter side to exhibit a spiral shape having winding elasticity. Have been.

An engaging portion 3 is provided in front of the mainspring 1. The engaging portion 3 serves as an engaging means for engaging with a member to be tightened (shown in FIG. 4) such as a bolt nut. It consists of a separate engaging member 3. The engaging member 3 is formed of a cylindrical body having a height slightly higher than the width of the mainspring 1, and has a regular hexagonal shape capable of fitting the member to be tightened to the inner peripheral portion of the engaging member 3 immovably. Are provided. Also, on the outer periphery of the engaging member 3, a spring A mounting groove 32 is provided for mounting on the front end of% 1. The mounting groove 32 is substantially L-shaped from the upper surface of the engaging member 3 and has a receiving portion 51 having a thickness of about 1 to 1.5 mm at the lower end side, and is approximately the same as the width of the mainspring 1. They are formed at the same depth. The front end of the spring 1 bent in a U-shape is fitted into the mounting groove 32 from above, so that the lower end of the spring 1 is received from the lower surface of the engaging member 3 to the receiving portion 5. It is non-rotatably mounted with the thickness of 1 above.

 The method of attaching the engaging member 3 and the front end of the mainspring spring 1 is not limited to the above-described one, but may be any one that can be attached so that it cannot be rotated, and is not particularly limited. Further, the engagement between the engagement member 3 and the front end of the mainspring 1 may be in a form of being detachably attached or in a fixed form. On the other hand, the fitting portion 31 of the engaging member 3 is not limited to a regular hexagonal shape, and the tightening member H such as a bolt and a nut is moved, such as a regular hexagonal shape. Any shape that can be improperly engaged is acceptable.

 At the rear end of the mainspring 1, a fixing means 4 is provided. The fixing means 4 is for fixing a member H to be fastened, such as a bolt or a nut, to a member S to be fastened, such as a building or pillow, to which the member H to be fastened is attached (shown in FIG. 4). The fixing means 4 in the present embodiment includes a ring portion 41 and a fixing member 42 such as a nail. The ring-shaped portion 41 is formed by winding and forming the rear end of the spiral spring 1 into a ring shape large enough to pass through the fixing member 42. Then, the fixing member 42 is inserted through the ring-shaped portion 41 and driven into the material S to be mounted, so that the ring-shaped portion between the large head 43 provided on the fixing member 42 and the material S to be mounted. 4 1 is made to be fixed.

The fixing member 42 is not limited to the one using a nail, but may be any one that can be fixed to the workpiece S, such as a wood screw, a self-drilling screw having a drill portion at the tip, and May be a general bolt or the like. For example, if the material S to be mounted is made of wood, nails or wood screws should be used, while if the material S to be mounted is made of reinforced steel, self-drilling screws should be used. The self-drilling can be tightened while turning the screw by turning the screw. Can be fixed according to. Further, the fixing member 42 may not be allowed to pass through the ring-shaped portion 41, or may be fixed to the rear end of the mainspring 1 in advance. However, if it is fixed in advance, it will be difficult to adapt to the type of material S to be mounted.Because of this, nails, wood screws, self-drilling screws, bolts, etc. can be selected and used at the construction site. Is preferred.

 Further, in this embodiment, when the rear end of the mainspring 1 is fixed to the material S to be mounted, a contact preventing means for preventing the lower end side of the spring 1 from contacting the material S to be mounted is provided. ing. The contact preventing means in this embodiment includes the receiving portion 51 provided on the above-described engaging member 3 and the protrusion 52 provided on the annular portion 41 on the rear end side of the mainspring 1. The projection 52 projects downward from the lower end of the ring-shaped portion 41 by a length of about 1 to 1.5 mm from the lower end of the mainspring 1. Then, the spring panel 1 fixed to the mounting material S by the receiving portions 51 and the projections 52 forms a lower end of the entire spring 1 from the front end to the rear end as shown in FIG. A gap t of about 1 to 1.5 mm is formed between the side and the workpiece S so that the lower end of the mainspring 1 does not contact the workpiece S. The height between the projection 52, the receiving portion 51 and the lower end of the mainspring 1 is not limited to about 1 to 1.5 mm, and is not particularly limited. The height of the projection 52 and the height of the receiving portion 51 may be different from each other, and may be changed as appropriate.

 In the present embodiment, the locking means 2 includes a locking member 21 for locking the mainspring spring 1 in a state having elasticity as shown in FIG. 1 (B), and a locking member 21. And a lock release mechanism for releasing the lock. The locking member 21 is made of a long cord-like member in which a thin steel wire is covered with a covering member, and is made of a bendable member.

The lock release mechanism is configured to release the lock of the lock member 21 when the rear end portion of the mainspring panel 1 is fixed to the workpiece S, and has the following configuration. That is, the main spring panel 1 is provided with a locking member 揷 through hole 22 provided at a rear end side in front of the ring-shaped portion 41, and the locking member 21 is provided with a locking portion from the outer periphery of the main spring panel 1. After passing through the material hole 22, the locking member 回 り crosses the illustrated lower end in the width direction of the spring 1 between the hole 22 and the ring-shaped portion 41, and turns to the outer peripheral side. It is wound around the outer peripheral side of the rear end portion 41, and in this way, the elastic spring panel 1 in an elastic state is locked so as not to expand. Therefore, in the spring 1 locked by the locking member 21, the portion from the locking member through hole 22 to the annular portion 41 is pushed obliquely upward by the locking member 21. As a result, the width direction is shifted from the other parts. As a result, the fixing member 42 such as 釕 is inserted through the ring-shaped portion 41 and the ring-shaped portion 41 is fixed to the workpiece S, so that the locking member 21 is cut or the locking member 21 is fixed. Is released downward, and the locking by the locking member 21 is released.

 Next, how to use the screw fastener will be described with reference to FIGS.

For example, when tightening the bolt H1 as the member H to be fastened to the wood S as the material S to be mounted, first, the fitting portion of the engaging member 3 is attached to the head of the bolt H1 attached to the wood S. 3 Fit 1 As a result, the radially inner front end side of the screw fastener is engaged with the bolt H1, and the screw fastener does not move even when the screw fastener is released. After that, the fixing member 42 is driven into the wood S through the annular portion 41. As a result, the rear end of the mainspring 1 is fixed to the wood S. In this fixed state, as described above, the contact is prevented from the front end to the rear end by the contact preventing means formed by the receiving portion 51 provided on the front end side of the mainspring 1 and the projection 52 provided on the rear end side of the mainspring 1. A gap t is formed between the lower end side of the entire spring 1 and the workpiece S. Also, when the fixing member 42 is driven into the wood S, the portion of the locking member 21 which is turned to the outer peripheral side from the lower end in the width direction of the mainspring 1 is cut by receiving a pressing force from the lower end of the mainspring 1, Alternatively, even when the mainspring 1 is not cut, the locking member 21 wound on the outer periphery of the mainspring 1 is pressed downward and disengages from the outer periphery of the mainspring 1 to release the lock. By releasing the locking of the locking member 21, the spring 1 is released and expanded by winding elasticity as shown in FIG. Is rotated, and the bolt H 1 engaged with this is also rotated. Thereby, the bolt HI can be tightened. Therefore, only the operation of fixing the rear end of the mainspring 1 is sufficient, and the operation of releasing the locking member 21 is not required, so that the operation can be simplified. In addition, when the mainspring is extended, the contact preventing means forms a gap t between the lower end of the mainspring 1 and the workpiece S, so that the spring panel 1 does not receive resistance from the workpiece S. The winding elasticity of the spring 1 can be directly transmitted to the bolt H1, and the bolt H1 can be securely tightened. At that time, for example, when the spring 1 is put in the case, the spring H1 cannot be expanded beyond the inner diameter of the case. As a result, there is a risk that the bolt H1 may not be able to be tightened to a certain tightening torque unless the bolt H1 is tightened to the wood S in advance with a certain tightening torque using a spanner or the like. In the present invention, after the locking member 21 is unlocked, there is nothing like a case to prevent the expansion of the mainspring 1, so that the bolt H 1 can be rotated more, and Even if the bolt IT1 is attached to the wood S, the bolt H1 can be tightened to a certain tightening torque. Therefore, even if a tool such as a wrench is not used, it is sufficient to simply set the bolt HI on the wood S by hand, and the operation can be facilitated.

 The tightening of the bolt H1 due to the elasticity of the spring 1 stops when the elastic force of the spring 1 and the tightening torque of the bolt H1 become equal, and the tightened bolt H1 releases the elasticity of the spring 1 Force is maintained in a biased state. Therefore, after a lapse of time, the wood S changes its diameter and the so-called wood S starts to fall, and when the tightening torque of the bolt H1 begins to decrease, the bolt H1 is elastically moved by the spring force of the spring 1. It can be tightened automatically and can always maintain a constant tightening torque. After the bolts HI are tightened, they may be left in that state.For example, as shown by the broken line in FIG. obtain.

If you use the screw fastener as described above, it will be elastic Since the mainspring spring 1 is only locked by the string-shaped locking member 21, the overall weight can be reduced as much as possible, and the labor for transportation and handling can be reduced. In addition, since there is no case for storing the mainspring 1 in the manufacturing process, the processing can be simplified, and the die can be manufactured at low cost with almost no need for a mold.

 In the present embodiment, the locking member through hole 22 of the locking release mechanism of the locking means 2 is formed at the lower end of the mainspring 1 in the width direction. The position of the mainspring 2 in the width direction is not particularly limited. However, if the spring spring 1 is provided at the lower end of the spring 1 in the width direction, the locking member 21 will come off the outer periphery of the spring 1 if the rear end of the spring 1 is not cut when the spring is fixed to the attached S. This is preferable because it is easy to release the lock.

 Further, the locking member passage hole 22 is not limited to this form. For example, as shown in FIG. 5, the upper end or the lower end in the width direction of the mainspring 1 (in FIG. 5, the opening from the lower end is formed). (Illustration), it may be opened at a predetermined depth, and even in this case, the locking member 21 can be turned to the outer peripheral side across the illustrated lower end of the mainspring spring 1 in the width direction. Further, by providing such a locking member insertion hole 22 having an opening at one end, when the rear end side of the mainspring 1 is fixed to the workpiece S, the lower end of the mainspring 1 in the width direction of the mainspring 1 can be used. The force to cut the part of the locking member 21 drawn on the side by the pressing force of the spring 1 or the pressing force of the spring 1 to remove the locking member 21 from the outer periphery of the spring 1 even if it cannot be cut. The locking member 21 can be securely released.

 The locking release mechanism of the locking means 2 is not limited to the one described above, and the locked locking member 21 is cut by an operation of fixing the rear end side of the mainspring 1 to the material S to be mounted. Or, it may be of any form that can be released from the outer periphery of the mainspring 1 and released from the lock.

For example, as shown in FIGS. 6 (A) and 6 (B), the mainspring spring 1 is provided with the locking member 揷 through hole 22, and at the rear end side of the mainspring spring 1, the vicinity of the locking member 揷 through hole 22 is checked. The inclined portion 11 is formed so that the portion from the rear end to the rear end is gradually raised in advance toward the rear end, and the locking member 21 is passed through the locking member through hole 22 to form the inclined portion. 1 Wrap around the spring 1 except for 1 and lock it. Then, when fixing to the mounting material S, the inclined portion 11 of the mainspring panel 1 is pressed by hand or the like until it comes into contact with a portion inside the diameter, and from that state, a ring-shaped portion provided at the rear end of the inclined portion 11 is formed. The fixing member 4 2 is driven into the part 4 1. In this way, when the fixing member 42 is driven, the inclined portion 11 is displaced in an ice flat shape, and the lower end of the inclined portion 11 is displaced in the horizontal displacement process. FIG. 6 shows the locking member 21 wound in the process of displacing the inclined portion 11 horizontally even when it is in contact with the locked locking member 21 and pressed downward to cut it, or even when it is not cut. (B) can be removed from the outer periphery of the mainspring 1 by sequentially pressing downward from the right to the left.

 Further, in this case, as shown in FIG. 7, a bent portion 12 bent toward the inside of the diameter is formed in the vicinity of the locking member 孔 through hole 22 of the mainspring 1, and the inclined portion 11 is previously formed with the diameter. It may be made to abut on the inner part, so that when fixing the fixing member 42, it is not necessary to perform the operation while pressing the inclined portion 11 with hand or the like, and the operation is performed. It can be easy.

 Further, the locking of the mainspring 1 by the locking means 2 is performed by simply winding the string-shaped locking member 21 around the entire outer periphery of the mainspring panel 1 and fixing the rear end of the mainspring 1 to the adherend S. The locking of the locking member 21 may be released.

 In addition, in the case of winding around the entire outer periphery of the mainspring 1 or in the case of providing the locking member through hole 22 having one end opening as shown in FIG. 5, an annular locking member 21 can be used.

In addition, the locking means 2 is not limited to the string-shaped locking member 21 and has locking pieces 21a and 21a at both ends, for example, as shown in FIGS. A locking member 21 is formed in a U-shape. The locking member 21 is spirally wound around a spring 1 in a state of being spirally wound. Set it so that it is located outside and inside the diameter of 1 and lock the spring 1 and after the spring 1 After the end is fixed to the mounting member S, the locking member 21 may be removed.

 Further, an engagement claw formed by cutting and raising a part of the mainspring 1 radially outward and an engagement hole formed in a part of the mainspring 1 are provided at a rear end side of the mainspring 1 on a radially outer side. The main spring 1 wound in a predetermined size is locked by the engaging claw and the engaging hole, and after locking the rear end of the mainspring 1 to the workpiece S, the locking is performed. It may be removed and can be changed as appropriate.

 Further, in this embodiment, a cylindrical engaging member 3 separate from the mainspring 1 is attached as the engaging means. For example, as shown in FIG. The engaging portion 3 having a fitting portion 31 into which the member to be tightened H can be fitted may be formed by bending and forming the same into a rectangular shape.

 Alternatively, as shown in FIG. 10 (A), an engagement piece 23 formed by bending a part of the front end of the mainspring 1 is used as an engagement portion, and this engagement piece 23 is provided on a bolt or a nut H2. Alternatively, the engagement may be performed by fitting into the engagement groove H3, and the bolt nut H2 having the engagement groove H3 may be used.

 Further, in the present embodiment, the front end of the mainspring 1 and the tightened member H are detachably engaged by the engaging means. However, the present invention is not limited to the form in which the engaging means is provided. As shown in FIG. 10 (B), the front end of the mainspring spring 1 and a bolt or nut H2 as a member to be tightened H are fixed and attached by an attaching means 7 such as welding, and then tightened. The spring 1 having the attachment member H can be implemented as a spring 1 and can be changed as appropriate.

Further, in the present embodiment, the contact preventing means is not limited to the force constituted by the receiving portion 51 provided on the engaging member 3 and the projection 52 provided on the ring-shaped portion 41, and is not limited to this form. When the rear end of the mainspring 1 is fixed to the workpiece S, the lower end of the mainspring 1 may not be in contact with the workpiece S, and may be changed as appropriate. Alternatively, only one of the receiving portion 51 and the protrusion 52 may be provided to serve as a contact preventing means. Even in this case, the lower end at the front end or the rear end of the mainspring 1 does not contact the workpiece S. The resistance when expanding the mainspring 1 can be reduced. Also, this It is not necessary to provide any contact preventing means, and it can be changed as appropriate.

 In the first and second inventions of the present application, if the locking member 21 is released, the member H to be tightened can be rotated and tightened by expanding the zemapane 1. Also, since there is nothing to hinder the expansion of the mainspring panel 1, the bolt H1 can be rotated more, and even if the bolt H1 is attached to the wood S by hand, the bolt H1 can be tightened to a certain tightening torque. Can be tightened. Therefore, even if a tool such as a wrench is not used, it is sufficient to simply set the bolt H1 on the wood S by hand, and the operation can be facilitated.

 Further, after the bolt H1 is tightened, the bolt H1 can be maintained in a biased state by applying the elastic force of the spring 1 to the bolt H1. Therefore, after a while, the wood S as the material to be mounted changes in diameter over time, and when the tightening torque of the bolt H1 starts to decrease, the bolt H1 is automatically turned on by the elastic force of the spring 1 accordingly. Tightening torque can be maintained at all times.

 On the other hand, since the spring 1 having elasticity is only locked by the locking member 21 in the form of a string, the overall weight can be reduced as much as possible, and the labor required for transportation and handling can be reduced. Can be something. In addition, since there is no case for housing the mainspring 1 in manufacturing, the processing can be simplified, and the die can be manufactured at low cost with almost no need for a mold.

 According to the third invention of the present application, the locking of the locking member 21 can be simultaneously released by one operation of fixing the rear end portion of the mainspring spring 1 to the workpiece S, and the operation can be facilitated.

Claims

The scope of the claims 1. A mainspring having a winding elasticity (1), and locking means (2) for locking the mainspring (1) in a state of having a winding elasticity,  The radially inner end of the mainspring (1) is engaged with a tightened member (H) such as a bolt and a nut, and the radially outer rear end of the mainspring (1) is fitted with the tightened member (H). Fixed to the mounting material (S),  Screw fastening, characterized in that the locking means (2) is of a type that can be unlocked 2. At the radially inner end of the mainspring (1), there is provided an engagement means (3) for non-rotatably engaging with a tightened member (H) such as a bolt or a nut. A fixing means (4) for fixing the member to be fastened (H) to the material to be mounted (S) is provided at the rear end portion of the radial outside of the spring (1). The screw fastener according to claim 1, wherein the claim includes: 3. The locking means (2) includes a string-shaped locking member (21), and a locking release mechanism (22) for releasing locking of the locking member (21).  The locking member (21) is powerfully wound around the outer periphery of the mainspring having a winding elasticity, whereby the mainspring spring (1) is locked in a state having the winding elasticity,  The locking release mechanism releases the locking of the locking member (21) when the rear end of the mainspring spring α) is fixed to the workpiece (S). Screw fastener according to Paragraph 1 or 2.