JP2012193807A - Fall prevention pin - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fall prevention pin excelling in work efficiency, diminishing a working load without using a mounting tool or the like, and allowing easy and sure attachment and detachment.SOLUTION: This fall prevention pin 1 is formed with a simple structure by a plurality of leg parts 21, 22, 23 having base ends 21a, 22a, 23a connected to a head part 10 and spirally extending along an axis L. The head part 10 is held by fingers and inserted in an insertion hole 113 for the respective leg parts of the fall prevention pin 1, following the insertion, the respective leg parts 21, 22, 23 slidably contact an opening edge 113b of the insertion hole 113 to be imparted with pressing force, the respective leg parts 21, 22, 23 are elastically deformed, and respective tip parts 21e, 22e, 23e projecting from an opening 113B are pressure-contacted to an opening edge 13c to be locked. The fall prevention pin 1 is surely mounted by simple work for inserting the fall prevention pin 1 in the insertion hole 113 by fingers of a worker, and a stable mounting state of the fall prevention pin 1 can be obtained without causing dispersion by a worker.

Description

  The present invention relates to a drop-off prevention pin, and more particularly to a drop-off prevention pin that is inserted into an insertion hole formed in a shaft portion.

  The high-voltage power transmission line is held in an insulator series attached to the power transmission tower. The insulator series is formed by connecting a plurality of suspended insulators in series.

  This hanging insulator is disclosed, for example, in Patent Document 1, and a perspective view is shown in FIG. 10 (a) and a cross section is shown in FIG. 10 (b). And a cap portion 105 attached to the upper outer peripheral surface of the insulator main body 101.

  The pin portion 102 has a base end attached to the inside of the insulator main body 101 via a fixing member such as cement, and a connecting hole through which the shaft portion 112 of the cotter pin 111 can be inserted into the lower end portion 103 protruding downward from the insulator main body 101. 104 is drilled.

  The cap portion 105 is attached in a bell shape covering the upper portion of the insulator main body 101 via a fixing member such as cement, and a clevis portion 106 is formed at the upper end of the cap portion 105. The clevis portion 106 includes a pair of protruding pieces 107A and 107B that protrude upward from the cap portion 105, and through holes 108A and 108B into which the shaft portion 112 of the cotter pin 111 can be inserted, respectively. It is formed.

  The cotter pin 111 has a shaft portion 112 that can be inserted into the connecting hole 104 of the pin portion 102 and the through holes 108A and 108B of the clevis portion 106, and a large-diameter head portion 114 that is integrally formed at the base end of the shaft portion 112. An insertion hole 113 that penetrates in the radial direction is formed in the distal end portion 112 a of the shaft portion 112. A split pin 115 is inserted into the insertion hole 113 as a fall prevention pin.

  The split pin 115 forms a substantially annular head portion 116 having a substantially elongated rod shape made of metal and having an intermediate portion folded back in a substantially arc shape, and the leg portions 117A and 117B come into contact with each other toward the same direction. It is extended.

  As shown in FIG. 11, each of the hanging insulators 100 formed in this manner has the other hanging insulator between the opposing projecting pieces 107 </ b> A and 107 </ b> B protruding from the clevis portion 106 of the one hanging insulator 100. The lower end portion 103 (shown by phantom lines) of the 100 pin portions 102 is inserted to hold the through holes 108A and 108B and the connecting hole 104 coaxially.

  With the through holes 108A and 108B and the coupling hole 104 held coaxially, the shaft 112 of the cotter pin 111 is inserted into the through hole 108A from the tip 112a side, and the through hole 108A, the coupling hole 104, and the through hole 108B are inserted. The tip 112a of the shaft 112 is protruded from the through hole 108B of the protruding piece 107B by penetrating.

  Then, for example, the head 116 of the split pin 115 is gripped with pliers or the like, and the leg portions 117A and 117B of the split pin 115 are inserted into the insertion hole 113 of the cotter pin 111 from the tip end portions 117Aa and 117Ba side, and the head 116 is inserted. Push in until the opening edge of the hole 113 abuts.

  Next, the end portions 117Aa and 117Ba of the leg portions 117A and 117B of the split pin 115 protruding from the insertion hole 113 of the cotter pin 11 are bent and opened. Thereby, the suspension levers 100 are connected to each other by the cotter pin 111.

  The split pins 115 are prevented from coming out of the insertion holes 113 of the cotter pins 111 by the bent leg portions 117A, 117B of the split pins 115 and the head portions 116Aa and 117Ba. Further, even if a force in the pulling direction acts on the cotter pin 111, the cotter pin 111 is locked by the tip portions 117Aa and 117Ba of the bent leg portions 117A and 117B of the split pin 115 and the head portion 116. The escape from the clevis portion 106 can be prevented.

  In addition, when the suspended insulator 100 is replaced with another new suspended insulator 100 due to breakage of the suspended insulator 100, first, the bent legs 117A and 117B of the split pin 1115 are restored to the original state by using pliers or the like. Return to. Then, the head 116 of the split pin 115 is gripped with pliers or the like, the split pin 115 is pulled out from the insertion hole 113 of the cotter pin 111, and the cotter pin 111 is pulled out from the clevis portion 106.

  On the other hand, various split pin mounting tools have been proposed. For example, as shown in FIG. 12, the split pin mounting tool of Patent Document 2 includes a first member 121 having an end portion of a first grip portion 122 operated by a worker's finger and a second grip portion 126 operated by a finger. A first member 121, and a pivot shaft 129 that pivotably supports the middle part of the first member 121 and the middle part of the second member 125, and the tip part of the first member 121. The first clamp part 123 having the arc-shaped concave first clamping surface 123 a is provided, and the second clamp part 127 having the arc-concave second clamping surface 127 a is provided at the tip of the second member 125.

  For example, as shown in FIG. 13A, the split pins 115 are inserted into the insertion holes 132 of the shaft member 131 by inserting the leg portions 117 </ b> A and 117 </ b> B of the split pin 115 with a fingertip or the like. And as shown in FIG.13 (b), the front-end | tip parts 117Aa and 117Ba of the leg parts 117A and 117B which protrude from the insertion hole 132 of the shaft member 131 are bent a little toward the outside. The front end portions 117Aa and 117Ba can be bent by the split pin attaching tool 120.

  Next, in a state where the first grip part 122 and the second grip part 126 of the split pin mounting tool 120 are gripped with fingers, the first clamp part 123 and the second clamp part 127 are pivoted as shown in FIG. The split pin attaching tool 120 is operated in a direction in which the first clamp part 123 and the second clamp part 127 are brought close to each other so as to sandwich the member 131 in the direction perpendicular to the axis of the shaft member 131. As a result, the first clamping surface 123a of the first clamp part 123 supports the head 116 of the split pin 115, and the tip part 117Aa of the leg part 117A of the split pin 115 is in contact with the second clamping surface 127a of the second clamp part 127. Touch.

  Further, when the first clamp part 123 and the second clamp part 127 are operated so as to approach each other, as shown in FIG. 13D, the second clamping surface 127a of the second clamp part 127 is the tip part of the leg part 117A. 117Aa is bent outward and the tip portion 117Ba of the leg portion 117B is bent.

JP 2009-150519 A JP 2008-141890 A

  According to the above-mentioned Patent Document 1, when connecting the suspension lever 100, the lower end portion 103 of the pin portion 102 of the other suspension lever 100 is inserted between the opposing protruding pieces 107A and 107B of the clevis portion 106 of one suspension lever 100. The shaft 112 of the cotter pin 111 is passed through the through hole 108A, the connecting hole 104, and the through hole 108B, and the tip 112a of the shaft 112 is protruded from the through hole 108B of the protruding piece 107B. Then, the head portion 116 of the split pin 115 is gripped with pliers or the like, and the leg portions 117A and 117B are inserted into the insertion hole 113 of the cotter pin 111, and further, the tip portions 117Aa and 117Ba of the leg portions 117A and 117B protruding from the insertion hole 113. The split pin 115 is attached by bending the pin with pliers or the like and opening the leg.

  However, since the leg portions 117Aa and 117Ba of the split pin 115 protruding from the insertion hole 113 of the cotter pin 111 are bent and opened by pliers or the like, the operation is troublesome and requires work time. Furthermore, the bending amounts of the tip portions 117Aa and 117Ba of the leg portions 117A and 117B are large, and the burden on the operator is increased. In addition, the skill of the operator is required to improve the work accuracy. Furthermore, since the bending work of the end portions 117Aa and 117Ba of the leg portions 117A and 117B is performed manually, there may be a large variation in the bending amount and bending angle for each worker. When the split pins 115 drop off, the cotter pins 111 fall off, resulting in a malfunction of the equipment, due to a shortage of the bending amount and bending angle of the legs 117A and 117B of the split pins 115.

  Furthermore, the attaching operation of the split pin 115 in the hanging lever 100 or the like is often performed at a high place or in a limited narrow working space, and the pliers that hold the legs 117A and 117B of the split pin 115 during the operation. Or the like may slip, or accidentally cause troubles such as breakage and dropping of the suspension insulator 100 by pliers or the like.

  Also, in the work of attaching the split pin 115 by the split pin attaching tool 120 disclosed in Patent Document 2, the tips 117Aa and 117Ba of the leg portions 117A and 117B of the split pin 115 are manually performed using the split pin attaching tool 120. The bending of the legs 117A and 117B is manually performed, so that the amount of bending and the angle of bending for each operator vary greatly. There is a concern about the same problems as in Patent Document 1.

  Accordingly, an object of the present invention made in view of such a point is to provide a drop-off prevention pin that can be easily and reliably attached and detached with reduced work load without using a mounting tool or the like and excellent workability. It is in.

  The invention of the fall-off prevention pin according to claim 1, which achieves the above object, includes a head part, and a base end part on the head part, in the fall-off prevention pin that is inserted into an insertion hole formed in the shaft part. And a plurality of legs extending in a spiral shape with the central axis as the center, and the legs are centered on the central axis as they move away from the base end connected to the head. A base end range that is spirally spaced from the central axis, a bulge range that is curved so as to approach the central axis continuously to the base end range, and the central axis is centered from the bulge range An insertion guiding range that gradually approaches the central axis and reaches the tip as the distance from the head increases.

  According to this, the drop-off prevention pin is configured with a simple configuration by a plurality of legs that are coupled to the head at the base and spirally extend along the central axis. Furthermore, without using a mounting tool, the head is gripped by fingers and the anti-detachment pins are inserted into the insertion holes from the distal end side of each leg, and the insertion guidance range of each leg is provided at the opening edge. When press-contacted, each leg is pressed against the central axis, the tip turns spirally, moves in the direction of the inner peripheral surface of the opposing insertion hole, and the tip protrudes from the opening, and the drop prevention pin Is pushed into the through hole and inserted into the opening edge, the bulging area continues to slide into the opening edge of the insertion hole and continues to the insertion guiding area of each leg. However, a pressing force is applied to the central axis side, and by applying the pressing force, each leg portion is elastically deformed and each distal end portion protruding from the opening is brought into pressure contact with the opening edge to be locked.

  As a result, the drop-off prevention pin is securely attached, but the drop-off prevention pin can be easily removed by grasping the head with fingers and pulling the drop-off prevention pin out of the through hole, reducing the burden on the operator. Excellent workability. Also, the drop-off prevention pin is securely attached by a simple operation of gripping the head with the operator's fingers and inserting the drop-off prevention pin into the insertion hole, and there is no variation by the operator, and the fall-off prevention pin is stably attached Is obtained.

  According to a second aspect of the present invention, in the dropout prevention pin according to the first aspect, the leg portions extend in directions different from each other with their tip ends shifted from the central axis, and the no-load state. The distance from the central axis to each tip is smaller than the radius of the insertion hole, the distance from the central axis to the bulging range is larger than the radius of the insertion hole, and each bulge is viewed from the extending direction of the central axis. The distance from the extended range to the tip is set larger than the diameter of the insertion hole.

  This is a more specific configuration of each leg portion of claim 1, and each tip portion is shifted from the center axis and extends in different directions, and from the center axis to each tip in an unloaded state. The distance is smaller than the radius of the insertion hole, the distance from the central axis to the bulging range is larger than the radius of the insertion hole, and the distance from each bulging range to the tip is in the state viewed from the extending direction of the central axis. By setting the diameter larger than the diameter of the insertion hole, the operation of the first aspect can be reliably performed.

  According to a third aspect of the present invention, in the dropout prevention pin according to the first or second aspect, each of the legs is formed of a stainless steel wire having a circular cross section.

  According to this, each leg is made of stainless steel wire with excellent rust resistance, so that it has excellent durability and a relatively small pushing force because it has a circular cross section with a small contact area with the opening edge. Can be inserted.

  According to a fourth aspect of the present invention, in the drop-off prevention pin according to any one of the first to third aspects, the head includes a leg holding portion for caulking the base ends of the leg portions and the leg holding portions. It is characterized by comprising a gripping part formed integrally with the part.

  According to this, the drop-off prevention pin can be easily configured by caulking the base ends of the leg portions with the leg holding portions integrally formed with the gripping portion.

  According to the present invention, the drop-off prevention pin is configured with a simple configuration including a plurality of legs that are coupled to the head at the base and spirally extend along the central axis. Without using an installation tool, grasp the head with your fingers and insert the anti-detachment pin into the insertion hole from the tip end of each leg. When contact is made, pressure is applied to move in the direction of the inner peripheral surface of the insertion hole, the tip protrudes from the opening, and each bulging range is brought into contact with the opening edge of the insertion hole and pressed to apply each pressing force. Each leg part elastically deforms and each tip part protruding from the opening presses against the opening edge to be locked.

  As a result, the drop-off prevention pin is securely attached, but the drop-off prevention pin can be easily removed by grasping the head with fingers and pulling the drop-off prevention pin out of the through hole, reducing the burden on the operator. Excellent workability. Also, the drop-off prevention pin is securely attached by a simple operation of gripping the head with the operator's fingers and inserting the drop-off prevention pin into the insertion hole, and there is no variation by the operator, and the fall-off prevention pin is stably attached Is obtained.

It is a perspective view which shows the state which mounted | wore the cotter pin with the fall-off prevention pin which concerns on one embodiment of this invention. It is a perspective view which shows the outline of a fall-off prevention pin. FIG. 3 is a view taken in the direction of an arrow III in FIG. FIG. 4 is a schematic view of the dropout prevention pin taken along the arrow IV in FIG. 2. FIG. 3 is a V arrow view of FIG. It is process explanatory drawing which shows the attachment process of a fall-off prevention pin typically, (a) is a side view, (b) is an arrow view of (a). It is process explanatory drawing which shows the attachment process of a fall-off prevention pin typically, (a) is a side view, (b) is an arrow view of (a). It is process explanatory drawing which shows the attachment process of a fall-off prevention pin typically, (a) is a side view, (b) is an arrow view of (a). It is process explanatory drawing which shows the attachment process of a fall-off prevention pin typically, (a) is a side view, (b) is an arrow view of (a). It is explanatory drawing of a suspension insulator, (a) is a perspective view of a suspension insulator, (b) is sectional drawing. It is explanatory drawing of the clevis part and split pin of a hanging insulator. It is explanatory drawing of a split pin attachment tool. It is explanatory drawing of the attachment work of the split pin by a split pin attachment tool.

  One embodiment of the present invention will be described with reference to FIGS. 1 to 9 by taking as an example a case where a detachment prevention pin is attached to a cotter pin connecting a suspended insulator. Note that the suspension lever and the cotter pin have the same configuration as the suspension lever 100 and the cotter pin 111 shown in FIG. 10, and a detailed description thereof will be omitted by attaching the corresponding reference numerals.

  FIG. 1 is a perspective view showing a state in which a drop-off prevention pin according to the present embodiment is mounted on a shaft portion of a cotter pin.

  As shown in FIG. 1, the lower end portion 103 (shown in phantom) of the pin portion 102 of the other suspension lever 100 is disposed between the protruding pieces 107A and 107B that protrude to face the clevis portion 106 of one suspension lever 100. The through holes 108A and 108B and the connection hole 104 are coaxially held by being inserted. The shaft 112 of the cotter pin 111 is inserted into the through hole 108A from the tip 112a side, and the through hole 108A, the coupling hole 104, and the through hole 108B are penetrated, and the tip 112a of the shaft 112 is inserted from the through hole 108B of the protruding piece 107B. Make it protrude.

  The drop-off prevention pin 1 is inserted into an insertion hole 113 formed in a radial direction through the tip 112a of the shaft 112 of the cotter pin 111 protruding from the protruding piece 107B.

  The drop prevention pin 1 will be described with reference to FIGS. 2 is a perspective view showing an outline of the drop-off prevention pin, FIG. 3 is a view taken along the arrow III in FIG. 1, FIG. 4 is a view taken along the arrow IV in FIG. 2, and FIG.

  The drop-off prevention pin 1 has a base 10 serving as a head and base ends 21 a, 22 a, 23 a coupled to the base 10, and a cross-section extending gently and spirally around the central axis L along the central axis L The three legs 21, 22, 23 formed of a circular wire are configured as main parts.

  These leg portions 21, 22 and 23 are preferably stainless steel wires having excellent rust resistance and rigidity.

  The base portion 10 is extended to the leg holding portion 11 and the leg holding portion 11 that integrally caulk-join the base end portions 21 a, 22 a, 23 a of the leg portions 21, 22, 23 arranged at equal intervals around the central axis L. An annular grip 12 is provided.

  The leg portions 21, 22, 23, whose base end portions 21 a, 22 a, 23 a are coupled to the leg holding portion 11, have the same shape, and the center axis line L changes as the distance from the leg holder portion 11 increases along the center axis line L. It has a base spiral range 21b, 22b, 23b that is a gentle spiral in the center and gradually separates from the central axis L, that is, gradually expands in diameter, and continuously to the distal end side of each base range 21b, 22b, 23b. The bulge ranges 21c, 22c, 23c formed so as to be gently curved so as to approach the central axis L, and the spiral leg holders centered on the central axis L from the bulge ranges 21c, 22c, 23c, respectively. The insertion guide ranges 21d, 22d, and 23d that gradually approach the central axis L as the distance from 11 is reached, that is, gradually decrease in diameter and reach the distal end portions 21e, 22e, and 23e, are continuously formed. In other words, the legs 21, 22, and 23 constituted by the three wires are gently continuous spirals with the central axis L as the center, and the base end side 21 a, 22 a, 22 a on the base 10 side to the tip end part 21 e. , 22e, 23e, proximal end ranges 21b, 22b, 23b that gradually increase in diameter, and bulge ranges 21c, 22c, 23c that are continuous with the proximal end ranges 21b, 22b, 23b and become large diameter ranges, The insertion guide ranges 21d, 22d, and 23d are formed by gradually reducing the diameter and reaching the tip portions 21e, 22e, and 23e.

  Further, as shown in FIG. 4, the leg portions 21, 22, and 23 have their tip portions 21 e, 22 e, and 23 e shifted from the central axis L and extending in different directions, and the central axis L in an unloaded state. From the center axis L to the bulging ranges 21c, 22c, and 23c, and the distance r1 from the tip end 21e, 22e, and 23e is smaller than the radius R of the insertion hole 113 of the shaft 112 of the cotter pin 111 (r1 <R). r2 is set larger than the radius R of the insertion hole 113 (r2> R).

  Further, the state seen from the extending direction of the central axis L, that is, the distance r3 from the bulging ranges 21c, 22c, 23c to the tip portions 21e, 22e, 23e in FIG. 4 is set larger than the diameter D of the insertion hole 113. (R3> D).

  As a result, the drop prevention pin 1 can be inserted into the insertion hole 113 from the respective tip end portions 21e, 22e, 23e side, and when inserted into the insertion hole 113 from the tip end portions 21e, 22e, 23e side, 22d and 23d are in contact with the opening edge of the insertion hole 113 and pressed against the central axis L, respectively, and the distal end portions 21e, 22e, and 23e rotate in a spiral shape and face the insertion hole 113 facing each other. Move to. Further, when the bulging ranges 21c, 22c, and 23c are pressed in contact with the opening edge or inner peripheral surface of the insertion hole 113, the tip portions 21e, 22e, and 23e are separated from each other while rotating in a gentle spiral shape. Move to spread outward.

  Next, a process of mounting the drop-off prevention pin 1 configured as described above in the insertion hole 113 formed through the shaft portion 112 of the cotter pin 111 will be described with reference to process explanatory diagrams shown in FIGS. . In each figure, (a) is a side view, (b) is an arrow view of (a), and the insertion hole 113 is indicated by a virtual line.

  When attaching the desorption prevention pin 1 to the through hole 113 of the cotter pin 111, as shown in FIGS. 6A and 6B, the operator grasps the holding portion 12 of the desorption prevention pin 1 with fingers, The tip portions 21e, 22e, and 23e are opposed to the opening 113A of the insertion hole 113 of the cotter pin 111.

  Then, the attachment / detachment prevention pin 1 is inserted into the insertion hole 113 from the distal end portions 21e, 22e, 23e of the leg portions 21, 22, 23, as shown in FIGS. 7 (a) and 7 (b). The insertion guide ranges 21d, 22d, and 23d of the legs 21, 22, and 23 are brought into contact with the opening edge 113b of the insertion hole 113 on the opening 113A side.

  When inserting the distal end portions 21e, 22e, 23e of the desorption prevention pin 1 into the insertion hole 113, the distance r1 from the central axis L of the distal end portions 21e, 22e, 23e of the leg portions 21, 22, 23 is set. By setting the radius smaller than the radius R of the insertion hole 113, the tip portions 21e, 22e, and 23e can be easily inserted into the insertion hole 113. Further, each insertion guide range 21d, 22d, 23d of each leg 21, 22, 23 is inserted into the insertion hole 113 while being smoothly guided by abutting or sliding against the opening edge 113b of the insertion hole 113, and dropped. The drop-off prevention pin 1 is self-centered (centered) so that the center axis L of the prevention pin 1 coincides with the center axis of the insertion hole 113.

  When each of the insertion guide ranges 21d, 22d, 23d abuts against the opening edge 113b and is centered with respect to the insertion hole 113, the drop prevention pin 1 is further pushed into the insertion hole 113. Accordingly, the insertion guide ranges 21d, 22d, and 23d of the leg portions 21, 22, and 23 are brought into sliding contact with the opening edge 113b of the insertion hole 113, and the insertion guide ranges 21d, 22d, and 23d of the leg portions 21, 22, and 23 are formed. A pressing force in the direction of the central axis L, that is, in the diameter reducing direction is applied, and by applying the pressing force, the leg portions 21, 22, and 23 are elastically deformed, and as shown in FIGS. 8A and 8B, the distal ends. The parts 21e, 22e, and 23e move closer to the inner peripheral surface 113a of the opposing insertion hole 113 while gently rotating in the spiral direction, and further protrude from the opening 113B.

  The drop-in prevention pin 1 is pushed into the insertion hole 113 in the direction of the central axis L where the insertion guide ranges 21d, 22d, and 23d of the leg portions 21, 22, and 23 that are in sliding contact with the opening edge 113b are the insertion direction. Compared with the fact that the insertion guide ranges 21d, 22d, and 23d are circular in section with a small contact area with the opening end edge 113b while maintaining the self-centering in the drop-off prevention pin 1 in comparison with the fact that the insertion guide ranges 21d, 22d, and 23d are circular in section. It can be inserted with less pushing force.

  Further, when the drop prevention pin 1 is pushed into the insertion hole 113 and the bulging areas 21c, 22c, and 23c are inserted into the opening edge 113b in succession to the insertion guide portions 21d, 22d, and 23d, they are pushed. Accordingly, the bulging ranges 21c, 22c, and 23c are slidably brought into contact with the opening edge 113b and the inner peripheral surface 113a of the insertion hole 113 in succession to the insertion guiding ranges 21d, 22d, and 23d of the legs 21, 22, and 23, respectively. The insertion guide ranges 21d, 22d, and 23d of the leg portions 21, 22, and 23 are given a pressing force in the direction of the central axis L, that is, in the diameter reducing direction, and the leg portions 21, 22, and 23 are elastically deformed by the pressing force application. As shown in FIGS. 9A and 9B, the tip portions 21e, 22e, and 23e protruding from the opening 113B are pressed and locked to the opening edge 113b while gently rotating in the spiral direction. .

  A drop-off prevention pin is provided by the tip portions 21e, 22e, 23e of the leg portions 21, 22, 23 that are in pressure contact with the opening edge 113b and the bulging ranges 21c, 22c, 23c that are in pressure contact with the inner peripheral surface 113a or the opening edge 113b. 1 is prevented from coming out of the insertion hole 113. Further, even if a force in the pulling direction is applied to the cotter pin 111, the drop prevention pin 1 is pressed against the opening edge 133c and protrudes from the end portions 21e, 22e, 23e protruding from the opening 113B and the leg portion 21 protruding from the opening 113A, Since the cotter pin 111 is locked by the base end ranges 21b, 22b, and 23b of the base plates 22 and 23 and the base portion 10, the cotter pin 111 can be prevented from falling off from the clevis portion 106.

  In addition, when the suspended insulator 100 is replaced with another new suspended insulator 100 due to breakage of the suspended insulator 100 or the like, first, the operator grasps the gripping portion 12 of the drop-off prevention pin 1 with fingers, and the center axis line Pull in the extending direction of L. As the grip portion 12 is pulled out, the bulging areas 21c, 22c, 23c of the leg portions 21, 22, 23 are pulled out from the opening edge 113b, and the inner peripheral surface 113a and the opening edge 113b of the through hole 113 are pressed. The distal end portions 21e, 22e, 21e, 22e, are released by swinging in the diameter increasing direction in which the insertion guiding ranges 21d, 22d, 23d are separated from the central axis L by the restoring force of the legs 21, 22, 23, that is, spring force. 23e moves in the direction of the diameter reduction while rotating slowly in the spiral direction, is released from the opening end edge 113b, is unlocked, and the drop-off prevention pin 1 is easily pulled out from the insertion hole swing 113.

  Therefore, according to the present embodiment, the base 10 serving as the head, and the base legs 21 a, 22 a, and 23 a are coupled to the base 10, and the three legs that gently extend along the central axis L The drop-off prevention pin 1 is configured with a simple configuration by the portions 21, 22, and 23. The drop-off prevention pin 1 is inserted into the insertion hole 113 of the cotter pin 111 by holding the base 10 with fingers without using a tool. While the pin 1 is securely attached, the drop-off prevention pin 1 can be easily pulled out by grasping the base 10 with fingers and pulling out the drop-off prevention pin 1 from the through hole 113, thereby reducing the burden on the operator. Excellent workability.

  Further, the drop-off prevention pin 1 is securely attached by a simple operation of gripping the base 10 with the operator's fingers and inserting the drop-off prevention pin 1 into the insertion hole 113 of the cotter pin 111, so that there is no variation by the operator and is stable. The attached state of the dropout prevention pin 1 is obtained.

  Note that the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the invention. For example, in the above embodiment, the base 10 and the three legs 21, 22, 23 constitute the drop-off prevention pin 1, but depending on the size of the insertion hole 113 to which the drop-off prevention pin 1 is attached, the coupling rigidity, etc. And a leg part can be comprised by four or more. Also. The present invention is not limited to the insertion hole 113 of the cotter pin 111, and can also be applied as a drop prevention pin for various shaft parts such as a shaft part of another connecting pin or a drop prevention pin for a bolt shaft part.

1 Captive pin 10 Base (head)
11 Leg holding part 12 Grip part 21, 22, 23 Leg part 21a, 22a, 23a Base end part 21b, 22b, 23b Base end range 21c, 22c, 23c Swelling range 21d, 22d, 23d Insertion guide part 21e, 22e, 23e End portion 100 Suspended insulator 101 Insulator body 102 Pin portion 103 Lower end portion 104 Connection hole 105 Cap portion 106 Clevis portion 107A, 107B Protruding piece 108A, 108B Through hole 111 Cotta pin 112 Shaft portion 112a Tip portion 113 Insertion hole 113a Inner peripheral surface 113b Open edge 113c Open edge 114 Head L Center axis

Claims (4)

In the fall prevention pin that is inserted and inserted into the insertion hole formed in the shaft part,
The head,
A base end portion coupled to the head and a plurality of legs extending in a spiral shape around the central axis;
Each of the leg portions has a spiral shape centered on the central axis as the distance from the proximal end portion coupled to the head portion increases, and a proximal range that gradually separates from the central axis, and continues to the proximal range. A bulging range that is curved so as to approach the central axis, and a spiral shape centering on the central axis from the bulging range, and an insertion guiding range that gradually approaches the central axis and reaches the tip as it moves away from the head A drop prevention pin characterized in that and are continuously formed. Each leg above
Each tip is displaced from the central axis and extends in different directions, and the distance from the central axis to each tip is smaller than the radius of the insertion hole in an unloaded state, and from the central axis to the bulging range The distance is larger than the radius of the insertion hole, and the distance from each bulging range to the tip end portion is set to be larger than the diameter of the insertion hole when viewed from the extending direction of the central axis. Item 2. The fall prevention pin according to Item 1.   The drop-off prevention pin according to claim 1 or 2, wherein each of the legs is formed of a stainless steel wire having a circular cross section.   4. The head according to claim 1, wherein the head includes a leg holding portion that caulks and joins the base ends of the leg portions, and a grip portion integrally formed with the leg holding portion. Detachment prevention pin as described.

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