Automatic fastening device

Abstract

To provide an automatic fastening device capable of maintaining the fastening force of a fastener over a long period and maintaining the aseismic performance of a building while enhancing the degree of freedom of an installation site, reducing the cost, and actualizing the simplification of work.SOLUTION: An automatic fastening device includes an outer sleeve 20, an inner sleeve 30 arranged in the outer sleeve, and a fastening member 40 inserted through the inner sleeve. An outer sleeve inner peripheral face 20a and an inner sleeve outer peripheral face 30a form a first guide part 60, and an inner sleeve inner peripheral face 30b and a fastening member outer peripheral facer 40a form a second guide part 70. When a gap G is caused between a nut 4 and a fixed member 8, the inner sleeve is moved with its weight to the fitting part 42 of the fastening member while being guided by a first guide part, whereby the fastening member is turned in the peripheral direction while being guided by a second guide part 70 and the nut is turned via the fitting part 42. The nut is threaded to a screw part 2a until losing a gap G.SELECTED DRAWING: Figure 12

Description

Technical Field

[0001] The present invention relates to an automatic fastening device, and more particularly to an automatic fastening device used for fixing a member to be fixed together with a fastening member composed of a bolt having a threaded portion and a nut screwed onto the threaded portion.

Background Art

[0002] Patent Document 1 discloses a screw tightening tool including a spiral spring having a winding elasticity and a locking means for locking the spiral spring in a state having a winding elasticity. The tip side on the inner diameter side of the spiral spring is engaged with a member to be tightened such as a bolt or a nut, and the rear end side on the outer diameter side of the spiral spring is fixed to a member to which the member to be tightened is attached. The locking means includes a locking member for locking the spiral spring in a state having a winding elasticity, and a locking release mechanism for releasing the locking of the locking member.

[0003] The locking release mechanism releases the locking of the locking member when the spiral spring is fixed to the member to which it is attached at the rear end portion. Thereby, even if a tightening operation is not performed with a constant tightening torque on a bolt or a nut that has loosened due to vibration, the bolt or the nut can be tightened with a natural constant tightening torque. Moreover, even when the bolt or the nut naturally loosens due to aging, that is, when so-called wood shrinkage occurs, a constant tightening torque can always be maintained.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] In the above screw fastener, the spring is directly engaged with a fastening member such as a bolt or a nut, and is fixed to the mounted member by a fixing member. Therefore, in the mounted member, it is necessary to secure an installation space for the screw fastener in the radial direction of the nut or the like. In particular, when fastening a large-diameter nut, using a large-diameter spring makes it difficult to secure an installation space, and also takes time for the installation work to install a large-diameter spring.

[0006] In addition, it is costly because an expensive spring is used. Also, in the process of tightening the nut with the spring, it is assumed that the elastic force of the spring gradually decreases, and ultimately the fastening force of the nut gradually decreases. Furthermore, after all the elastic force of the spring is used for the additional tightening of the nut, the fastening force of the fastener cannot be maintained.

[0007] The present invention has been made in view of such problems, and aims to provide an automatic fastening device that can increase the degree of freedom of the installation location, reduce the device cost, simplify the installation work, maintain the fastening force of the fastener over a long period, and thus maintain the seismic performance of the building.

Means for Solving the Problems

[0008] In order to achieve the above object, an automatic fastening device of the present invention is an automatic fastening device used to fix a member to be fixed together with a fastening member composed of a bolt having a threaded portion and a nut screwed onto the threaded portion. The automatic fastening device has a fixing portion fixed to the member to be fixed, a cylindrical outer sleeve disposed with the fixing portion at the lower end, a cylindrical inner sleeve disposed movably in the axial direction of the outer sleeve within the outer sleeve, and within the outer sleeve, movement in the axial direction is blocked while rotation in the circumferential direction is permitted. The automatic fastening device is inserted into the inner sleeve, has a fitting portion fitted to the nut at one end, and has an insertion hole through which a bolt protruding from the nut is inserted. An inner circumferential surface of the outer sleeve and an outer circumferential surface of the inner sleeve form a first guide portion over their axial directions, and an inner circumferential surface of the inner sleeve and an outer circumferential surface of the fastening member form a second guide portion over their axial directions. When a gap is generated between the nut and the member to be fixed, the inner sleeve moves toward the fitting portion while being guided by the first guide portion due to its own weight, so that the fastening member rotates in the circumferential direction while being guided by the second guide portion, and further the nut rotates through the fitting portion, and the nut is screwed into the threaded portion until the gap disappears.

Effect of the Invention

[0009] According to the automatic fastening device of the present invention, it is possible to increase the degree of freedom of the installation location, reduce the device cost, further simplify the installation work, maintain the fastening force of the fastening member over a long period, and thus maintain the seismic performance of the building.

Brief Description of the Drawings

[0010]

Figure 1

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Figure 12

Mode for Carrying Out the Invention

[0011] Hereinafter, the automatic fastening device 1 according to an embodiment of the present invention will be described with reference to the drawings. Note that the concepts of "up" and "down" in the following description are those within the scope of the drawings and can vary depending on the installation state of the automatic fastening device 1. FIG. 1 shows a front view of the automatic fastening device 1 in the installed state. The automatic fastening device 1 (hereinafter also simply referred to as the device 1) is used to fix a member to be fixed together with a fastening tool 6 composed of a bolt 2 having a threaded portion 2a and a nut 4 screwed onto the threaded portion 2a.

[0012] Hereinafter, a specific installation example of the device 1 will be described. As shown in FIG. 1, in a building having a plurality of floors, a long bolt 2 passes through the beams (members to be fixed) 8 of each floor, and the bolt 2 is fastened with a nut 4 at each beam 8. Each beam 8 and the fastening tool 6 composed of the bolt 2 and the nut 4 are positioned, for example, inside a wall (not shown) in the interior of the building. In this case, it is difficult to access the fastening tool 6 or the device 1 for additional tightening of the nut 4 or the like. Here, due to the shrinkage of the beam 8 or the loosening of the nut 4 caused by vibration, a gap may occur between the beam 8 and the nut 4.

[0013] The device 1 is inserted through the bolt 2 and attached to the nut 4. Even in a situation where it is difficult to access the fastener 6 or the device 1, the nut 4 is automatically screwed in to eliminate the gap. As a result, the fastening force of the fastener 6 to the beam 8 is maintained, and thus the seismic performance of the building is maintained. Also, as shown in FIG. 1, since the device 1 in the installed state has a compact structure in the radial direction of the nut 4, the device 1 can be easily installed in a narrow space inside the wall along the bolt 2.

[0014] FIG. 2 shows a perspective view of the device 1 as viewed from above, FIG. 3 shows a perspective view of the device 1 as viewed from below, and FIG. 4 shows a longitudinal sectional view of the device 1 attached to the nut 4. As shown in FIG. 4, the device 1 mainly includes a cylindrical outer sleeve 20, a cylindrical inner sleeve 30, and a tubular fastening member 40. The outer sleeve 20 has a fixing portion 22 for fixing the device 1 to the beam 8, and the fixing portion 22 is arranged with its lower end.

[0015] The fixing portion 22 is a plate-like portion formed at the lower end of the outer sleeve 20 and protrudes in pairs in the radial direction of the outer sleeve 20. Specifically, each fixing portion 22 has a notched locking portion 22a (see FIGS. 2 and 3). By fitting the locking portion 22a into the screw 10 (see FIGS. 1 and 4) driven into the beam 8 or driving the screw 10 into the locking portion 22a, the device 1 is detachably fixed to the upper surface of the beam 8 at each fixing portion 22.

[0016] Thereby, when the device 1 operates and the fastening member 40 rotates, the device 1 itself is prevented from rotating together with the fastening member 40. As shown in FIG. 4, the inner sleeve 30 is arranged to be movable in the axial direction (vertical direction) of the outer sleeve 20 within the outer sleeve 20. The inner sleeve 30 of the present embodiment has a weight that can move downward while rotating due to its own weight, and thus can rotate the fastening member 40. Preferably, it is made of metal, for example, formed from cast iron.

[0017] The fastening member 40 is inserted into the inner sleeve 30 while being prevented from moving in the axial direction and allowed to rotate in the circumferential direction within the outer sleeve 20. The fastening member 40 has a fitting portion 42 that fits onto the nut 4 at its lower end (one end), and an insertion hole 44 through which the bolt 2 protruding from the nut 4 is inserted. The installation work of the device 1 is performed by fitting the fitting portion 42 onto the nut 4 and fixing the locking portion 22a of the fixing portion 22 to the beam 8 with the screw 10.

[0018] The device 1 can be installed by such a simple operation. Simultaneously with the completion of this installation work, the rotation of the device 1 with respect to the beam 8 is prevented by each fixing portion 22. As shown in FIGS. 2 to 4, a pair of locking holes 24 are formed below the inner sleeve 30 of the outer sleeve 20. By inserting and attaching a pin-shaped locking member (not shown) into the locking holes 24, the inner sleeve 30 is supported within the outer sleeve 20 by the locking member so as not to fall, and in this state, the device 1 can be stored and transported.

[0019] As shown in FIG. 4, the inner peripheral surface 20a of the outer sleeve 20 and the outer peripheral surface 30a of the inner sleeve 30 form a first guide portion 60 over their axial directions. Specifically, the first guide portion 60 forms spiral engaging portions 62 that engage with each other on the inner peripheral surface 20a of the outer sleeve 20 and the outer peripheral surface 30a of the inner sleeve 30 to move the inner sleeve 30 while rotating it in the circumferential direction.

[0020] Furthermore, the inner peripheral surface 30b of the inner sleeve 30 and the outer peripheral surface 40a of the fastening member 40 form a second guide portion 70 over their axial directions. Specifically, the second guide portion 70 forms linear engaging portions 72 that engage with each other on the inner peripheral surface 30b of the inner sleeve 30 and the outer peripheral surface 40a of the fastening member 40 to convert the above-described rotation of the inner sleeve 30 into the circumferential rotation of the fastening member 40.

[0021] FIG. 5 shows a perspective view of the outer sleeve 20, and FIG. 6 shows a longitudinal sectional view of the outer sleeve 20. A spiral rib portion 26 (see FIG. 6) is formed on the inner peripheral surface 20a of the outer sleeve 20. Further, as described above, at the lower end of the outer sleeve 20, fixing portions 22 having locking portions 22a are formed in pairs, and a pair of locking holes 24 are formed above at least the middle portion of the outer sleeve 20 in the height direction.

[0022] FIG. 7 shows a perspective view of the inner sleeve 30, and FIG. 8 shows a longitudinal sectional view of the inner sleeve 30. A spiral groove portion 32 is formed at a position on the outer peripheral surface 30a of the inner sleeve 30 that faces the spiral rib portion 26 of the outer sleeve 20. The above-described spiral engagement portion 62 is formed by the spiral rib portion 26 formed on the inner peripheral surface 20a of the outer sleeve 20 and the spiral groove portion 32 formed on the outer peripheral surface 30a of the inner sleeve 30 meshing with each other. Further, on the inner peripheral surface 30b of the inner sleeve 30, linear groove portions 34 are formed in pairs at positions facing each other in the radial direction along the axial direction of the inner sleeve 30.

[0023] FIG. 9 shows a perspective view of the fastening member 40, FIG. 10 shows a longitudinal sectional view of the fastening member 40, and FIG. 11 shows a perspective view of the washer 48 attached to the upper end of the outer sleeve 20. Linear rib portions 46 are formed in pairs at positions on the outer peripheral surface 40a of the fastening member 40 that face the respective linear groove portions 34 of the inner sleeve 30. Further, as described above, a fitting portion 42 into which the nut 4 is fitted is formed at the lower end of the fastening member 40, and an insertion hole 44 for the bolt 2 is formed inside the fastening member 40.

[0024] The straight meshing portion 72 is formed by the engagement of a pair of straight concave ridges 34 formed on the inner peripheral surface 30b of the inner sleeve 30 and a pair of straight convex ridges 46 formed on the outer peripheral surface 40a of the fastening member 40. Further, a locking groove 52 is formed on the outer peripheral surface 40a at the upper end of the fastening member 40. The washer 48 shown in FIG. 11 is positioned at the upper end of the outer sleeve 20 (see FIGS. 2 and 4), and the inner teeth 48a of the washer 48 are locked in the locking groove 52. Thereby, the fastening member 40 is prevented from moving in the axial direction and allowed to rotate in the circumferential direction within the outer sleeve 20.

[0025] FIG. 12 shows a longitudinal sectional view of the device 1 when a gap G occurs between the nut 4 and the beam 8. First, in the state shown in FIG. 4, the locking member is removed from the locking hole 24 to release the support of the inner sleeve 30, and the device 1 is set. Then, it is assumed that a gap G as shown in FIG. 12 occurs between the nut 4 and the beam 8 due to shrinkage of the beam 8 or loosening of the nut 4 caused by vibration. In other words, the gap G is formed by the bolt 2 moving slightly upward by the amount of the gap (see FIG. 4) between the nut 4 and the fitting portion 42 due to shrinkage of the beam 8 or loosening of the nut 4.

[0026] In this case, the inner sleeve 30 moves while rotating in the circumferential direction, specifically, in the clockwise direction as viewed from above, toward the fitting portion 42, that is, downward, while being guided by the first guide portion 60 (i.e., the spiral meshing portion 62) by its own weight from the initial set state (state (1)). Along with this, the fastening member 40 rotates in the circumferential direction, specifically, in the clockwise direction as viewed from above, while being guided by the second guide portion 70 (i.e., the straight meshing portion 72) (state (2)).

[0027] Along with this, the nut 4 rotates in the clockwise direction as viewed from above through the fitting portion 42 (state (3)), the nut 4 is screwed onto the threaded portion 2a (state (4)), and the state without the gap G as shown in FIG. 4 is achieved. It should be noted that the transition from these states (1) to state (4) actually occurs instantaneously each time a minute gap G occurs, and thus is not a slow operation that can be visually observed.

[0028] As described above, the device 1 of the present embodiment includes the outer sleeve 20, the inner sleeve 30, and the fastening member 40 described above. By shifting from the state (1) to the state (4) described above, the gap G formed between the nut 4 and the beam 8 is eliminated. As a result, the fastening force of the fastener 6 with respect to the beam 8 is maintained, and thus the seismic performance of the building is maintained.

[0029] In addition, since the device 1 in the installed state has a compact structure in the radial direction of the nut 4, the degree of freedom in the installation location of the device 1 can be increased. In particular, even when fastening a large-diameter nut 4, the installation space for the device 1 can be easily secured, and it is not necessary to install a large-diameter spring, so the installation work can be carried out in a short time. Furthermore, since the nut 4 is tightened more by utilizing the self-weight of the inner sleeve 30, it is not necessary to use an expensive spring, and since no other parts are required, the device cost can be significantly reduced.

[0030] Furthermore, if the weight of the inner sleeve 30 is preset, the elastic force of the spring will not gradually decrease during the fastening of the nut 4 as in the case of using a spring, and thus the fastening force of the nut 4 will not gradually decrease. Also, the situation where all of the elastic force of the spring is used for further tightening the nut 4 as in the case of using a spring will not occur, and the fastening force of the fastener 6 with respect to the beam 8 can be maintained over a long period by the rotation of the inner sleeve 30 due to its self-weight.

[0031] More specifically, the first guide portion 60 forms a spiral meshing portion 62 that meshes with the inner peripheral surface 20a of the outer sleeve 20 and the outer peripheral surface 30a of the inner sleeve 30 to move the inner sleeve 30 while rotating it in the circumferential direction. The second guide portion 70 forms a linear meshing portion 72 that meshes to convert the rotation of the inner sleeve 30 into the circumferential rotation of the fastening member 40.

[0032] Furthermore, the spiral engagement portion 62 is formed by the spiral rib portion 26 formed on the inner peripheral surface 20a of the outer sleeve 20 and the spiral groove portion 32 formed on the outer peripheral surface 30a of the inner sleeve 30 engaging with each other. On the other hand, the linear engagement portion 72 is formed by a pair of linear groove portions 34 formed on the inner peripheral surface 30b of the inner sleeve 30 and a pair of linear rib portions 46 formed on the outer peripheral surface 40a of the fastening member 40 engaging with each other.

[0033] Thus, in the device 1, the first guide portion 60 and the second guide portion 70, that is, the spiral engagement portion 62 and the linear engagement portion 72 are positioned above the fitting portion 42 fitted to the nut 4. Thereby, in the device 1, a conversion mechanism that converts the rotation of the inner sleeve 30 into the rotation of the fastening member 40 and thus the fitting portion 42 can be positioned at a position separated from the nut 4 that is the fastening target. Therefore, even when only a narrow space can be secured around the nut 4 and the device 1, the device 1 can be installed, and both an increase in the degree of freedom of the installation location of the device 1 and a simplification of the installation work can be effectively realized.

[0034] Also, even if the first guide portion 60 is formed from a linear engagement portion such as the linear engagement portion 72 and linearly moved, and the second guide portion 70 is formed from a spiral engagement portion such as the spiral engagement portion 62 and rotated, the operation of the device 1 can be realized. However, when the first guide portion 60 is formed from the spiral engagement portion 62, the moving distance accompanied by the rotation of the inner sleeve 30 when a gap G is generated becomes long. In particular, by reducing the gradient of the spiral shape of the spiral engagement portion 62, the moving distance accompanied by the rotation of the inner sleeve 30 further increases, and the inner sleeve 30 becomes more likely to rotate during movement.

[0035] By realizing smooth rotation of the inner sleeve 30, the weight and size of the inner sleeve 30 can be reduced, enabling the apparatus 1 to be made more compact and further reducing the apparatus cost. Also, as the moving distance of the inner sleeve 30 increases, a greater tightening margin that allows further tightening of the nut 4 can be ensured, so that the fastening force of the fastener 6 by the apparatus 1 can be maintained over a longer period.

[0036] Furthermore, the fixing portion 22 is formed to project diametrically in pairs at the lower end of the outer sleeve 20 and is locked to the beam 8 via the screws 10, thereby preventing the rotation of the apparatus 1 with respect to the beam 8 when the fastening member 40 rotates. Thereby, by forming the fixing portion 22 that projects radially at the lower end of the outer sleeve 20 and having a simple configuration that only locks to the screws 10, the apparatus 1 can be detachably rotationally blocked and fixed to the beam 8. Therefore, simplification of the installation work of the apparatus 1 can be surely realized.

[0037] Also, the apparatus 1 includes a locking member that supports the inner sleeve 30 within the outer sleeve 20. Thereby, during the installation work of the apparatus 1, the work can be performed without manually supporting the inner sleeve 30 having a certain weight, and the inner sleeve 30 can be released and the apparatus 1 can be set by a simple operation of only removing the locking member. Therefore, further simplification of the installation work of the apparatus 1 can be achieved.

[0038] This concludes the description of the embodiments of the present invention. However, the present invention is not limited to the above embodiments, and various modifications can be made without departing from the spirit of the present invention. For example, as described above, the spiral engagement portion 62 is formed by the spiral ridge portion 26 formed on the inner peripheral surface 20a of the outer sleeve 20 and the spiral groove portion 32 formed on the outer peripheral surface 30a of the inner sleeve 30 engaging with each other.

[0039] However, the spiral engagement portion 62 may be formed with the unevenness reversed on the inner peripheral surface 20a of the outer sleeve 20 and the outer peripheral surface 30a of the inner sleeve 30. Similarly, the linear engagement portion 72 may also be formed with the unevenness reversed on the inner peripheral surface 30b of the inner sleeve 30 and the outer peripheral surface 40a of the fastening member 40. Further, although the effect of the first guide portion 60 being the spiral engagement portion 62 is as described above, if there is no problem in not obtaining this effect, the first guide portion 60 may be a linear engagement portion where a linear concave groove portion and a linear convex rib portion are engaged, instead of the spiral engagement portion 62. In this case, the second guide portion 70 will form a spiral engagement portion where a spiral concave groove portion and a spiral convex rib portion are respectively engaged.

[0040] Also, in the above embodiment, the device 1 is used to maintain the fastening force of the fastener 6 to the beam 8. However, not limited to this, the device 1 can be widely used for fastening various woods where there is concern about wood shrinkage, and various materials other than wood where there is concern about loosening of the nut 4 due to vibration, such as metal materials and resin materials.

Explanation of Reference Numerals

[0041] 1 Automatic fastening device 2 Bolt 2a Threaded portion 4 Nut 6 Fastener 8 Beam (member to be fixed) 20 Outer sleeve 20a Inner peripheral surface of outer sleeve 22 Fixed portion 26 Spiral convex rib portion 30 Inner sleeve 30a Outer peripheral surface of inner sleeve 30b Inner peripheral surface of inner sleeve 32 Spiral concave groove portion 34 Linear concave groove portion 40 Fastening member 40a Outer peripheral surface of fastening member 42 Fitting portion 44 Insertion hole 46 Linear convex rib portion 60 First guide portion 62 Spiral meshing part 70 Second guide part 72 Linear meshing part G Gap

Claims

1. An automatic fastening device used to fix a member to be fixed together with a fastening member composed of a bolt having a threaded portion and a nut screwed onto the threaded portion, having a fixing portion fixed to the member to be fixed, and a cylindrical outer sleeve disposed with the fixing portion as a lower end, a cylindrical inner sleeve disposed movably in the axial direction of the outer sleeve within the outer sleeve, within the outer sleeve, movement in the axial direction is blocked while rotation in the circumferential direction is permitted, inserted into the inner sleeve, having a fitting portion fitted to the nut at one end, and having an insertion hole through which the bolt protruding from the nut is inserted, a fastening member is provided, the inner circumferential surface of the outer sleeve and the outer circumferential surface of the inner sleeve form a first guide portion over their axial directions, the inner circumferential surface of the inner sleeve and the outer circumferential surface of the fastening member form a second guide portion over their axial directions, when a gap occurs between the nut and the member to be fixed, the inner sleeve moves toward the fitting portion while being guided by the first guide portion due to its own weight, whereby the fastening member rotates in the circumferential direction while being guided by the second guide portion, and further the nut rotates through the fitting portion, and the nut is screwed into the threaded portion until the gap disappears, an automatic fastening device.

2. The first guide portion forms a spiral engagement portion that meshes with the inner circumferential surface of the outer sleeve and the outer circumferential surface of the inner sleeve to move the inner sleeve while rotating it in the circumferential direction, The second guide portion forms a linear engagement portion that meshes with the inner circumferential surface of the inner sleeve and the outer circumferential surface of the fastening member to convert the rotation of the inner sleeve into rotation in the circumferential direction of the fastening member, the automatic fastening device according to claim 1.

3. The spiral engagement portion is formed by the spiral ridge portion formed on the inner circumferential surface of the outer sleeve and the spiral groove portion formed on the outer circumferential surface of the inner sleeve meshing with each other, the automatic fastening device according to claim 2.

4. The linear engagement portion is formed by a pair of linear groove portions formed on the inner circumferential surface of the inner sleeve and a pair of linear ridge portions formed on the outer circumferential surface of the fastening member meshing with each other, the automatic fastening device according to claim 3.

5. The fixing portion is formed to protrude radially in pairs at the lower end of the outer sleeve, and when the fastening member rotates by being locked to the member to be fixed, rotation of the automatic fastening device with respect to the member to be fixed is blocked. The automatic fastening device according to claim 1.

6. The automatic fastening device according to claim 1, further comprising a locking member that supports the inner sleeve within the outer sleeve.

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