Tightening device

Abstract

To provide a tightening device that can avoid a state where the screw is only partially engaged. [Solution] The fastening device 2 comprises a main body 3, a screw piece 4 on which a male thread portion 4b, which is part of the circumferential direction of the male screw 4a, is formed, and a shaft 5. The main body 3 has an insertion portion 3a that is inserted into the screw hole 1a of the female screw member 1, and a contact surface 3b that contacts the contact surface 1b of the female screw member 1. The screw piece 4 moves between a first position where it is housed in the insertion portion 3a and a second position where it protrudes from the outer circumferential surface of the insertion portion 3a. The second position is located on the side of the first direction 6a, where the insertion portion 3a is inserted into the screw hole 1a, and the angle 7a of the direction of movement 7 in which the screw piece 4 moves, with respect to the axis 4c of the male screw 4a, is smaller than the angle 4f of the hypotenuse 4e on the second direction 6b side of the screw thread 4d of the male thread portion 4b, which is opposite to the first direction 6a. The shaft 5 moves in the direction of the axis 4c and presses against the screw piece 4, causing the screw piece 4 to move from the first position to the second position.

Description

Technical Field

[0001] This invention relates to a tightening device provided with a movable screw member.

Background Art

[0002] Conventionally, there has been a screw device having a retractable screw portion (see, for example, Patent Document 1). As shown in FIG. 15, this screw device 21 (lock bolt) includes a tubular shaft 22, an operating rod 23 inserted therein and movable vertically in the axial direction, and a lock element 24 having a screw portion 24a. Here, the lock element 24 is inserted into an opening 22a provided on the lower side of the tubular shaft 22, and is movable between a position where the screw portion 24a provided on the front side protrudes from the opening 22a and a position where the screw portion 24a is accommodated in the opening 22a. And, a convex portion 23a and a concave portion 23b are provided on the lower side of the operating rod 23, and a convex portion 24b and a concave portion 24c are provided on the back side of the lock element. When the operating rod 23 is in the raised position (see FIG. 15), the convex portion 23a and the convex portion 24b face each other, so that the lock element 24 is in a position where the screw portion 24a protrudes from the opening 22a. When the operating rod 23 is in the lowered position, the convex portion 23a and the concave portion 24c, and the concave portion 23b and the convex portion 24b face each other, so that the lock element 24 can be moved to a position where the screw portion 24a is accommodated in the opening 22a. And, a spring 25 is provided in the tubular shaft 22, and by this spring 25, the operating rod 23 is biased to the raised position, and normally, the lock element 24 is in a position where the screw portion 24a protrudes from the opening 22a. And, by pressing a push button 26 provided at the upper end of the operating rod 23, the operating rod 23 moves to the lowered position, and at the same time, the lock element 24 can be moved to a position where it is accommodated in the opening 22a. Further, the lower side of the tubular shaft 22 is formed with a small diameter, and the upper side is formed with a large diameter, and the boundary thereof is a shoulder portion 22b. Therefore, when the lower side of the tubular shaft 22 is inserted into the screw hole of the female screw member in a state where the push button 26 is pressed, the shoulder portion 22b (specifically, a seal 22c provided on the shoulder portion) hits the upper surface of the female screw member.

Prior Art Documents

[0003] [Patent Document 1] DE 202019106029 U1 [Overview of the Initiative] [Problems that the invention aims to solve]

[0004] Incidentally, in the conventional screw device 21, after pressing the push button 26 with a finger to insert the lower side of the tubular shaft 22 into the screw hole 27a of the female screw member 27, and then releasing the finger from the push button 26, the locking element 24 moves radially outward along the inner circumferential surface of the opening 22a. However, before this movement is complete, the threads 24d of the screw portion 24a (i.e., the male thread) of the locking element 24 may come into contact with the upper hypotenuse 27c that forms the valley 27b of the female thread in the screw hole 27a (see Figure 16). In this case, since the shoulder portion 22b of the tubular shaft 22 is in contact with the upper surface of the female thread member 27 (seal 22c omitted), the threads 24d of the threaded portion 24a (male thread) cannot enter the valleys 27b of the female thread any further. In this partially engaged state, the tubular shaft 22 (thread device 21) may be rotated, causing the threaded portion 24a to be screwed into the threaded hole 27a.

[0005] This invention was made to solve the aforementioned drawbacks of the conventional methods, and its purpose is to provide a tightening device that can avoid a state where the screw is only partially engaged. [Means for solving the problem]

[0006] The fastening device according to this invention has the following configuration in order to achieve the above objective. That is, The fastening device according to claim 1 comprises a cylindrical body, a screw piece having a male thread portion formed on it which is part of the circumferential direction of the male thread, and a shaft. Here, the body extends in the direction of the axis of the male thread. The body also has an insertion portion which is inserted into the screw hole of a female screw member, and a contact surface which faces and contacts the contact surface of the female screw member when the insertion portion is inserted into the screw hole, thereby completing the insertion. The screw piece is provided to be movable between a first position in which it is incorporated into the insertion portion and housed in the insertion portion so as to be able to move in and out of the screw hole, and a second position in which it protrudes from the outer circumferential surface of the insertion portion so as to be screwed into the female thread of the screw hole. At this time, the second position is located on the side of the first direction for inserting the insertion part into the screw hole, and in a plane including the axis of the male screw, the angle of the direction of movement of the screw piece with respect to the axis is smaller than the angle of the hypotenuse of the threads of the male screw on the side of the second direction for withdrawing the insertion part from the screw hole. The main body has a guide surface that guides the screw piece in the direction of movement, and the screw piece has a guided surface that contacts the guide surface and is guided in the direction of movement. The shaft is located inside the main body, facing the direction of the axis of the male screw, and is movable in the direction of that axis. Therefore, when the shaft presses against the screw piece, the screw piece is guided by the guide surface and moves from the first position to the second position.

[0007] According to this fastening device, in order to fasten it to a female threaded member, first, the screw piece is placed in the first position, and the insertion part of the main body is inserted into the threaded hole of the female threaded member until the contact surface of the main body contacts the contact surface of the female threaded member. Then, the screw piece is moved from the first position to the second position. Here, the second position is located on the side of the first direction in which the insertion part is inserted into the threaded hole, and in the plane containing the axis of the male thread, the angle of the direction in which the screw piece moves with respect to that axis is smaller than the angle of the hypotenuse on the second direction side of the thread of the male thread (that is, the hypotenuse on the second direction side of the valley of the female thread). For this reason, the thread of the male thread does not abut against the hypotenuse on the second direction side of the valley of the female thread while the screw piece is moving from the first position to the second position.

[0008] Therefore, as the screw insert moves from the first position to the second position, when the threads of the male screw portion abut against the hypotenuse on the first direction side of the valley of the female screw, the threads of the male screw portion advance along the hypotenuse on the first direction side of the valley of the female screw, and the main body moves in the second direction in addition to the screw insert, causing the contact surface of the main body to separate from the contact surface of the female screw member, and thus the screw insert can move to the second position. After that, the main body is rotated in the tightening direction of the male screw to screw the male screw portion into the screw hole.

[0009] Furthermore, if the top of the thread on the male screw part comes into contact with the top of the thread on the female screw part as the screw piece moves from the first position to the second position, the main body rotates together with the screw piece, disengaging the contact between the tops, and allowing the screw piece to move from the first position to the second position.

[0010] Furthermore, the fastening device according to claim 2 of the invention is the fastening device according to claim 1, further comprising an elastic member for the screw piece that biases the screw piece toward the inside of the insertion portion. Thus, the screw piece is biased by the elastic member for the screw piece and is in the first position, and is pressed by the shaft, causing it to move toward the second position against the biasing force of the elastic member for the screw piece.

[0011] Furthermore, the fastening device according to claim 3 comprises, in the fastening device according to claim 2, an operating member provided on the side of the main body opposite to the insertion portion, and a first elastic member. The main body has a guide hole in its peripheral wall, the guide hole having a vertical hole extending in the direction of the axis of the male screw and a horizontal hole continuing from the vertical hole and extending on the first direction side toward the tightening rotation side of the male screw. The shaft has a retaining hole in its peripheral wall. A pin-shaped member is attached to the operating member, which is inserted into the guide hole and the retaining hole. The operating member is therefore movable between a standby position located on the second direction side and a push-in position located on the first direction side with respect to the main body via the pin-shaped member guided in the vertical hole, and is also rotatable between the push-in position and a push-in rotation position located on the tightening rotation side of the male screw from the push-in position via the pin-shaped member guided in the horizontal hole. The first elastic member is provided to bias the shaft toward the first direction relative to the operating member. When the operating member is in the standby position, the pin-shaped member is in contact with one of the circumferential surfaces of the holding hole, which is the circumferential surface toward the second direction, with the shaft toward the second direction and the screw piece in the first position. When the operating member is moved from the standby position to the push-in position, the pin-shaped member moves away from the one circumferential surface of the holding hole, the shaft, biased by the first elastic member, presses against the screw piece, and the screw piece is guided by the guide surface and moves toward the second position. When the operating member is rotated from the push-in position to the push-rotation position, the pin-shaped member, biased by the first elastic member via the operating member, contacts the circumferential surface of the lateral hole toward the second direction, and the operating member maintains its pushed-in state.

[0012] Furthermore, the fastening device according to claim 4 comprises a second elastic member in addition to the fastening device according to claim 3. This second elastic member has a smaller biasing force than the first elastic member and biases the shaft toward the second direction relative to the main body. Therefore, when the operating member is in the standby position, the pin-shaped member that contacts one of the circumferential surfaces of the holding hole is subjected to the biasing force of the second elastic member and contacts one of the circumferential surfaces of the vertical hole that is on the second direction side.

[0013] Furthermore, the fastening device according to claim 5 is the fastening device according to any one of claims 1 to 4, wherein the pressed surface of the screw piece that is pressed against the shaft has an inclination angle that is symmetrical with respect to a plane perpendicular to the axis of the male screw with respect to the guided surface. [Effects of the Invention]

[0014] According to the fastening device of this invention, as the screw piece moves from the first position to the second position, the threads of the male screw portion do not abut against the hypotenuse on the second direction side of the valley of the female screw, thereby avoiding a state of partial thread engagement. [Brief explanation of the drawing]

[0015] [Figure 1] This is a perspective view of a fastening device according to one embodiment of the present invention. [Figure 2] Similarly, this is a disassembled perspective view of the fastening device. [Figure 3] Similarly, this is a longitudinal cross-sectional view of a tightening device with the operating member in a standby position. [Figure 4] Similarly, this is a cross-sectional view taken along line AA in Figure 3. [Figure 5] Similarly, this is a longitudinal cross-sectional view of a tightening device with the operating member in the pressed-in position. [Figure 6] Similarly, this is a cross-sectional view taken along the BB line in Figure 5. [Figure 7]Also, it is an enlarged development view showing the relationship between the guide hole of the main body and the pin-shaped member. (a) shows the position of the pin-shaped member when the operating member is in the standby position, (b) shows the position of the pin-shaped member when the operating member is in the pushed-in position, and (c) shows the position of the pin-shaped member when the operating member is in the pushed-in rotation position. [Figure 8] Also, it shows a screw member. (a) is an enlarged front view, (b) is an enlarged side view, and (c) is an enlarged cross-sectional view taken along line C-C. [Figure 9] Also, it is an enlarged side view showing a pair of screw members. [Figure 10] Also, it is a longitudinal sectional view when the insertion part of the tightening device with the operating member in the standby position is inserted into the screw hole of the female screw member. [Figure 11] Also, following FIG. 10, it is a longitudinal sectional view when the operating member is in the pushed-in position. [Figure 12] Also, it is an enlarged view of part D in FIG. 11. [Figure 13] Also, following FIG. 11, it is a longitudinal sectional view when the operating member is in the pushed-in rotation position and the pushed-in state of the operating member is maintained. [Figure 14] Also, it is an enlarged view of part E in FIG. 13. [Figure 15] It is a sectional view showing a conventional screw device. [Figure 16] Also, it is a schematic diagram for explanation when, with the push button pressed, the lower side of the screw device is inserted into the screw hole of the female screw member and then the finger is released from the push button.

Embodiments for Carrying Out the Invention

[0016] Hereinafter, embodiments for carrying out this invention will be described based on the drawings.

[0017] FIGS. 1 to 14 show an embodiment of the present invention. In the figures, reference numeral 1 indicates a female screw member, and 2 indicates a tightening device.

[0018] The fastening device 2 comprises a cylindrical body 3, a screw piece 4 on which a male thread portion 4b, which is part of the circumferential direction of the male thread 4a, is formed, and a shaft 5. Here, the body 3 extends in the direction of the axis 4c of the male thread 4a. The body 3 has an insertion portion 3a that is inserted into the screw hole 1a of the female screw member 1, and a contact surface 3b that comes into contact with the contact surface 1b of the female screw member 1 when the insertion portion 3a is inserted into the screw hole 1a, thereby completing the insertion.

[0019] The screw piece 4 is incorporated into the insertion portion 3a of the main body 3. The screw piece 4 is provided to be movable between a first position (see Figures 3 and 10) in which it is housed in the insertion portion 3a so that the insertion portion 3a can move in and out of the screw hole 1a, and a second position (see Figures 5 and 13) in which it protrudes from the outer surface of the insertion portion 3a so that the male thread portion 4b of the screw piece 4 is screwed into the female thread 1c of the screw hole 1a. Here, the second position is located on the side of the first direction 6a (i.e., the direction from the rear end of the main body 3 toward the front end where the insertion part 3a is located) that inserts the insertion part 3a into the screw hole 1a, compared to the first position. In the plane containing the axis 4c of the male screw 4a, the angle 7a of the direction of movement 7 in which the screw piece 4 moves, with respect to the axis 4c, is set to be smaller than the angle 4f of the hypotenuse 4e on the side of the thread 4d of the male screw part 4b that withdraws the insertion part 3a from the screw hole 1a in the second direction 6b (i.e., the direction from the front end where the insertion part 3a is located toward the rear end of the main body 3, and the direction opposite to the first direction 6a) (see Figure 8(c)).

[0020] Therefore, the main body 3 has a guide surface 3c that guides the screw piece 4 in the direction of movement 7, and the screw piece 4 has a guided surface 4g that contacts the guide surface 3c and is guided in the direction of movement 7. In the illustrated embodiment, the guide surface 3c and the guided surface 4g are formed flat, and the angle between the guide surface 3c and the guided surface 4g with respect to the axis 4c of the male screw 4a is the angle 7a of the direction of movement 7 (see Figure 8(c)).

[0021] The shaft 5 is located inside the main body 3 and is oriented in the direction of the axis 4c of the male screw 4a, and is movable in the direction of that axis 4c. When the shaft 5 presses against the screw piece 4, the screw piece 4 is guided by the guide surface 3c and moves from the first position to the second position.

[0022] In detail, the fastening device 2 includes an elastic member 8 for the screw thread (a tension coil spring in the illustrated embodiment) that biases the screw thread 4 toward the inside of the insertion portion 3a that houses the screw thread 4. That is, the screw thread 4 is biased by the elastic member 8 for the screw thread and is in a first position, and is pressed by the shaft 5, causing it to move against the biasing force of the elastic member 8 to a second position.

[0023] The tightening device 2 also includes an operating member 9 and a first elastic member 10, which are provided on the opposite side of the insertion portion 3a of the main body 3 (i.e., the rear end side). The main body 3 has a guide hole 3d in its peripheral wall, and the guide hole 3d has a vertical hole 3e extending in the direction of the axis 4c of the male screw 4a, and a horizontal hole 3f that follows the vertical hole 3e and extends on the tightening rotation side of the male screw 4a on the first direction 6a side (in the illustrated embodiment, it is on the tightening rotation side of the male screw 4a and extends in a direction perpendicular to the vertical hole 3e). The shaft 5 has a retaining hole 5a in its peripheral wall (in the illustrated embodiment, the retaining hole 5a is an elongated hole extending in the direction of the axis 4c of the male screw 4a). A pin-shaped member 11 is attached to the operating member 9, which is inserted into the guide hole 3d and the retaining hole 5a. Therefore, the operating member 9 is movable relative to the main body 3 between a standby position located on the side of the second direction 6b (see Figures 3, 4, 7(a), and 10) and a push-in position located on the side of the first direction 6a (see Figures 5, 6, 7(b), and 11) via a pin-shaped member 11 guided by a vertical hole 3e of the guide hole 3d. The operating member 9 is also rotatable relative to the main body 3 between the push-in position and a push-in rotation position located on the tightening rotation side of the male screw 4a from the push-in position (see Figures 7(c) and 13) via a pin-shaped member 11 guided by a horizontal hole 3f of the guide hole 3d.

[0024] The first elastic member 10 is provided to bias the shaft 5 toward the first direction 6a relative to the operating member 9. When the operating member 9 is in the standby position, the pin-shaped member 11 is in contact with one of the circumferential surfaces 5b of the holding hole 5a, which is the circumferential surface on the second direction 6b side (that is, in contact with one of the circumferential surfaces 5b due to the biasing force of the first elastic member 10), and the shaft 5 is on the second direction 6b side, with the screw piece 4 in the first position. When the operating member 9 is moved from the standby position to the push-in position, the pin-shaped member 11 moves away from one of the circumferential surfaces 5b of the holding hole 5a, and the shaft 5, under the biasing force of the first elastic member 10, presses against the screw piece 4, which is then guided by the guide surface 3c and moves toward the second position. Then, when the operating member 9 is rotated from the pressed position to the pressed-rotate position, the pin-shaped member 11, which is biased by the first elastic member 10 via the operating member 9, comes into contact with the circumferential surface 3g of the lateral hole 3f on the side of the second direction 6b (in the illustrated embodiment, the recessed surface at the far end provided on the side of the lateral hole 3f in the second direction 6b), and the operating member 9 is held in the pressed state.

[0025] Furthermore, the clamping device 2 is equipped with a second elastic member 12. This second elastic member 12 has a smaller biasing force than the first elastic member 10 (more specifically, significantly smaller), and biases the shaft 5 relative to the main body 3 toward the second direction 6b. Therefore, when the operating member 9 is in the standby position, the pin-shaped member 11, which contacts one of the circumferential surfaces 5b of the holding hole 5a due to the biasing force of the first elastic member 10, is also affected by the biasing force of the second elastic member 12 and contacts one of the circumferential surfaces 3h of the vertical hole 3e in the guide hole 3d, which is the circumferential surface on the side of the second direction 6b. Conversely, the position of the operating member 9 when the pin-shaped member 11 contacts one of the circumferential surfaces 3h of the vertical hole 3e is the standby position.

[0026] Specifically, the main body 3 comprises a cylindrical main body member 301, a ring member 302 having the aforementioned contact surface 3b, and a columnar member 303 having the aforementioned guide surface 3c. The main body member 301 is formed in a stepped shape and consists of a small-diameter main body portion 3i on the first direction 6a side and a large-diameter main body portion 3j on the second direction 6b side. The inner holes of the main body member 301 are formed through, and the inner holes of the small-diameter main body portion 3i consist of a small-diameter hole 3k on the first direction 6a side and a medium-diameter hole 3m on the second direction 6b side, while the inner hole of the large-diameter main body portion 3j consists of a large-diameter hole 3n. The ring member 302 is fastened to the main body member 301 at an intermediate position of the small-diameter main body portion 3i using a set screw 13, and the surface of the ring member 302 on the first direction 6a side becomes the aforementioned contact surface 3b. The main body member 301 (main body 3) has an insertion portion 3a on the side of the ring member 302 that is in the first direction 6a. An elongated hole 3p is made in the side wall of this insertion portion 3a so as to be in an opposing position. The columnar member 303 is fitted into the inside of the tip portion of the insertion portion 3a (main body 3) (i.e., the small diameter hole 3k) and secured by a spring pin 14. The side of the columnar member 303 that is in the second direction 6b is inclined in a wedge shape, and both of these inclined surfaces become the guide surfaces 3c. In other words, two guide surfaces 3c are provided so as to be in a symmetrical position.

[0027] The screw piece 4 has a pressing surface 4h that is pressed against the shaft 5, and this pressing surface 4h has an inclination angle that is symmetrical with respect to a plane perpendicular to the axis 4c of the male screw 4a with respect to the guide surface 4g. Two of these screw pieces 4 are provided, corresponding to the two guide surfaces 3c, 3c. These screw pieces 4, 4 are inserted into the two elongated holes 3p, 3p of the main body 3, respectively, with the male screw portion 4b facing outwards and the opposite back surfaces facing each other. The screw piece 4 has a hole 4i on its back surface. The ends of the aforementioned elastic member 8 for screw pieces (specifically, a tension coil spring) are inserted into the holes 4i, 4i of the two screw pieces 4, 4, and each end is secured to the screw piece 4 by a parallel pin 15.

[0028] Furthermore, the length of the screw piece 4 in the direction of the axis 4c of the male screw 4a is P × (N + 0.5) with respect to the pitch P of the male screw 4a (where N is any integer), with the peak of the male screw 4a positioned at one end of that length and the trough of the male screw 4a positioned at the other end of that length, and in addition, both sides of that length are cut by the same height h (where h is a value including 0) to obtain a length L (in the illustrated embodiment, both ends are further chamfered), so that one type of screw piece 4 can be used in common by reversing one end of its length (see Figure 9).

[0029] The shaft 5 consists of a small-diameter shaft portion 5c on the side of the first direction 6a and a large-diameter shaft portion 5d on the side of the second direction 6b. The large-diameter shaft portion 5d is formed in a cylindrical shape, and the aforementioned holding hole 5a is provided in its peripheral wall. Thus, the small-diameter shaft portion 5c of the shaft 5 is inserted into the small-diameter hole 3k and the medium-diameter hole 3m of the main body member 301 (main body 3), and the large-diameter shaft portion 5d is inserted into the large-diameter hole 3n of the main body member 301 (main body 3). The tip of the small-diameter shaft portion 5c is formed in a conical shape, and the shaft 5 presses the screw piece 4 (more specifically, the pressed surface 4h) with the surface 5e of the cone.

[0030] The operating member 9 is formed in a cup shape and is placed over the large-diameter main body portion 3j of the main body 3. This operating member 9 has a hole 9a in its peripheral wall. The aforementioned pin-shaped member 11 is inserted through this hole 9a, the guide hole 3d, and the retaining hole 5a, and is fastened to the operating member 9 at the hole 9a by a set screw (not shown).

[0031] The first elastic member 10 and the second elastic member 12 are made of, for example, compression coil springs. As mentioned above, the biasing force of the second elastic member 12 is smaller than that of the first elastic member 10. Conversely, the biasing force of the first elastic member 10 is larger than that of the second elastic member 12, and in particular, its biasing force is set to be sufficiently large. Here, the first elastic member 10 is inserted into the inner hole of the large-diameter shaft portion 5d of the shaft 5, and at one end it presses against the bottom surface of the hole, and at the other end it presses against the top surface of the operating member 9. The second elastic member 12 is fitted onto the small-diameter shaft portion 5c of the shaft 5 and inserted into the medium-diameter hole 3m of the main body 3, and at one end it presses against the step portion of the main body 3 moving from the medium-diameter hole 3m to the small-diameter hole 3k, and at the other end it presses against the step portion of the shaft 5 moving from the small-diameter shaft portion 5c to the large-diameter shaft portion 5d.

[0032] Next, the operation and effects of the fastening device 2 having the above configuration will be explained. To fasten the fastening device 2 into the female screw member 1 in which a screw hole 1a is formed, first, the screw piece 4 is set to the first position (in the illustrated embodiment, the operating member 9 is set to the standby position and the shaft 5 is held on the side of the second direction 6b, thereby setting the screw piece 4 to the first position), and the insertion portion 3a of the main body 3 is inserted into the screw hole 1a of the female screw member 1 until the contact surface 3b of the main body 3 contacts the contact surface 1b of the female screw member 1. After that, the screw piece 4 is moved from the first position to the second position (in the illustrated embodiment, the operating member 9 is moved from the standby position to the push-in position, and then rotated to the push-in rotation position to move the screw piece 4 from the first position to the second position).

[0033] Here, the second position is located on the side of the first direction 6a, where the insertion part 3a is inserted into the screw hole 1a, compared to the first position. In the plane containing the axis 4c of the male screw 4a, the angle 7a of the direction of movement 7 in which the screw piece 4 moves (see Figure 8(c)) is smaller than the angle 4f of the hypotenuse 4e of the thread 4d of the male screw portion 4b on the side of the second direction 6b, where the insertion part 3a is withdrawn from the screw hole 1a (that is, the angle 1f of the hypotenuse 1e of the valley 1d of the female screw 1c on the side of the second direction 6b (see Figures 12 and 14)). Therefore, as the screw piece 4 moves from the first position to the second position, the thread 4d of the male screw portion 4b does not come into contact with the hypotenuse 1e of the valley 1d of the female screw 1c on the side of the second direction 6b.

[0034] Therefore, as the screw piece 4 moves from the first position to the second position, when the threads 4d of the male thread portion 4b abut against the hypotenuse 1g on the first direction 6a side of the valley 1d of the female thread 1c (see Figure 11 (in detail, Figure 12)), the threads 4d of the male thread portion 4b advance along the hypotenuse 1g on the first direction 6a side of the valley 1d of the female thread 1c, and the main body 3 moves in the second direction 6b in addition to the screw piece 4, causing the contact surface 3b of the main body 3 to separate from the contact surface 1b of the female thread member 1, and thus the screw piece 4 can move to the second position (see Figure 13 (in detail, Figure 14)). After that, the main body 3 is rotated in the tightening direction of the male thread 4a (in the illustrated embodiment, the operating member 9 is rotated in the tightening direction of the male thread 4a, thereby rotating the main body 3 in that direction), and the male thread portion 4b is screwed into the screw hole 1a.

[0035] Furthermore, when the screw piece 4 moves from the first position to the second position, if the top of the thread 4d of the male thread 4b comes into contact with the top of the thread 1c of the female thread, the main body 3 rotates together with the screw piece 4, disengaging the contact between the tops, and the screw piece 4 can move from the first position to the second position.

[0036] In other words, unlike conventional screw devices, this tightening device 2 prevents the threads 4d of the male thread portion 4b from hitting the hypotenuse 1e on the second direction 6b side of the valley 1d of the female thread 1c while the screw piece 4 is moving from the first position to the second position, thus avoiding a state of partial thread engagement (i.e., preventing the screw from being tightened while only partially engaged).

[0037] It should be noted that the present invention is not limited to the embodiments described above, and various other modifications are possible. For example, although the clamping device 2 includes a second elastic member 12, this second elastic member 12 may be omitted.

[0038] Furthermore, in this tightening device 2, when the operating member 9 is pushed in, the shaft 5 presses against the screw piece 4, causing the screw piece 4 to move from the first position to the second position. Alternatively, when the operating member 9 is pulled up, the shaft 5 may press against the screw piece 4 by hooking it from the side that has passed it, causing the screw piece 4 to move from the first position to the second position. Alternatively, the operating member 9 may be rotated, for example by tilting the vertical groove 3e, so that the shaft 5 presses against the screw piece 4.

[0039] Furthermore, the tightening device 2 includes an operating member 9 and a first elastic member 10 that biases the operating member 9, and the shaft 5 is moved by operating the operating member 9. However, the shaft 5 may be moved directly without providing the operating member 9 or the first elastic member 10.

[0040] Furthermore, although the tightening device 2 is equipped with an elastic member 8 for the screw thread, this elastic member 8 for the screw thread is optional.

[0041] Furthermore, the pressed surface 4h of the screw piece 4, which is pressed against the shaft 5, has an inclination angle that is symmetrical with respect to the plane perpendicular to the axis 4c of the male screw 4a with respect to the guided surface 4g, but it does not necessarily have to have an inclination angle that is symmetrical.

[0042] Furthermore, the contact surface 3b is the back surface of the ring member 302, but if a washer or the like is added to the back of the ring member 302, then naturally the back surface of that washer or the like becomes the contact surface 3b. Also, the ring member 302 is fixed to the main body member 301, but it may be formed integrally from the beginning. [Explanation of symbols]

[0043] 1 Female threaded member 1a Screw hole 1b Contact surface 1c Female thread 2. Tightening device 3 Main unit 3a Insertion part 3b Contact surface 3c Guide surface 3d guide hole 3e vertical hole 3f horizontal hole Circumferential surface of the second direction side of the 3g transverse hole 3h One side of the vertical hole 4 screw inserts 4a Male screw 4b Male threaded section 4c axis center 4d thread 4e hypotenuse 4f Angle of the hypotenuse 4g guided surface 4h Pressed surface 5 shafts 5a Retaining hole 5b One circumferential surface of the retaining hole 6a 1st direction 6b 2nd direction 7 Direction of movement 7a Angle of the direction of movement 8 Elastic component for screw threads 9 Operating Member 10 First elastic member 11 Pin-shaped member 12. Second elastic member

Claims

1. A fastening device comprising a cylindrical body, a screw piece having a male thread portion formed on it which is part of the circumferential direction of the male thread, and a shaft, The main body extends in the direction of the axis of the male screw, and, The main body has an insertion portion that is inserted into the screw hole of the female screw member, and a contact surface that comes into contact with the contact surface of the female screw member when the insertion portion is inserted into the screw hole, thereby completing the insertion. The screw piece is incorporated into the insertion part and is housed in the insertion part so as to be able to move in and out of the screw hole, and is provided to be movable between a first position in which the insertion part is housed in the insertion part so as to be able to move in and out of the screw hole, and a second position in which the male screw portion protrudes from the outer surface of the insertion part so as to be screwed into the female screw of the screw hole. The second position is located on the side of the first direction for inserting the insertion part into the screw hole, and in a plane containing the axis of the male screw, the angle of the direction of movement of the screw piece with respect to that axis is smaller than the angle of the hypotenuse of the threads of the male screw portion on the second direction side for withdrawing the insertion part from the screw hole. The main body has a guide surface that guides the screw piece in the direction of movement, and the screw piece has a guided surface that contacts the guide surface and is guided in the direction of movement. The shaft is located within the main body, faces the direction of the axis of the male screw, and is movable in the direction of that axis. A fastening device in which the shaft presses against the screw thread, causing the screw thread to be guided by the guide surface and move from the first position to the second position.

2. The screw insert is provided with an elastic member for the screw insert that biases it toward the inside of the insertion portion, The fastening device according to claim 1, wherein the screw piece is biased by the elastic member for the screw piece to be in the first position, and is pressed by the shaft to move against the biasing force of the elastic member for the screw piece to the second position.

3. The main body comprises an operating member provided on the side opposite to the insertion portion and a first elastic member, The main body is provided with a guide hole in its peripheral wall, the guide hole having a vertical hole extending in the direction of the axis of the male screw and a horizontal hole continuing from the vertical hole and extending on the first direction side toward the tightening rotation side of the male screw, The shaft has a retaining hole in its peripheral wall, The operating member is fitted with a pin-shaped member that is inserted into the guide hole and the holding hole, and The operating member is movable between a standby position located on the second direction side and a push-in position located on the first direction side relative to the main body via the pin-shaped member guided in the vertical hole, and is also rotatable between the push-in position and a push-in rotation position located on the tightening rotation side of the male screw relative to the main body via the pin-shaped member guided in the horizontal hole. The first elastic member is provided such as to bias the shaft toward the first direction relative to the operating member. When the operating member is in the standby position, the pin-shaped member is in contact with one of the circumferential surfaces of the holding hole, which is the circumferential surface on the second direction side, and the shaft is on the second direction side and the screw piece is in the first position. When the operating member is moved from the standby position to the pressed position, the pin-shaped member moves away from one of the circumferential surfaces of the holding hole, the shaft, under the biasing force of the first elastic member, presses against the screw piece, and the screw piece is guided by the guide surface and moves toward the second position. The fastening device according to claim 2, wherein when the operating member is rotated from the pressed position to the pressed-rotating position, the pin-shaped member, which is biased by the first elastic member via the operating member, strikes the circumferential surface of the lateral hole on the second direction side, and the operating member maintains its pressed state.

4. A second elastic member is provided, The second elastic member has a smaller biasing force than the first elastic member, and biases the shaft relative to the main body toward the second direction. The fastening device according to claim 3, wherein when the operating member is in the standby position, the pin-shaped member that contacts one of the circumferential surfaces of the holding hole is subjected to the biasing force of the second elastic member and contacts one of the circumferential surfaces of the vertical hole that is on the second direction side.

5. The fastening device according to any one of claims 1 to 4, wherein the pressed surface of the screw piece that is pressed against the shaft has an inclination angle that is symmetrical with respect to a plane perpendicular to the axis of the male screw with respect to the guided surface.

Images