JP5706099B2 - Screw clamp - Google Patents

Description

  The present invention relates to a screw-type clamp, and more particularly to a tightening bolt structure thereof.

  From a clamp body having a pair of opposing legs, receiving means provided on one of the pair of legs, and a fastening bolt structure screwed into a female screw hole formed through the other leg Therefore, a screw-type clamp that is fastened and fixed between the suspended object and the receiving means by moving the tightening bolt structure close to the receiving means is well known and widely used in various construction sites. However, in the case where the engagement teeth are formed at the tip of the tightening bolt structure itself, the rotational force accompanying the rotation of the bolts during tightening acts on the suspended object, or the engagement teeth are covered. There were disadvantages such as deeply digging into the engaged surface of the suspended object and scratching it, and when the engaging teeth were worn, the entire tightening bolt structure had to be replaced, resulting in high costs. .

  In order to eliminate this disadvantage, the fastening bolt structure 20 proposed by the present applicant in Patent Document 1 has a female screw hole and a screw formed through one leg of the clamp body as shown in FIG. A bolt main body 21 having a male screw 23 to be mated on its outer peripheral surface, and a pad 22 attached to the tip of the bolt main body 21 so as to be relatively rotatable and detachable. A female thread portion 26 and a female thread portion 26 are formed at the relative end of either the bolt body 21 or the pad 22 (the bolt body 21 in FIG. 1) adjacent to the inner thread portion 26. A counterbore portion 27 having an inner diameter larger than the female thread valley diameter of the female thread portion 26 and an opening formed adjacent to the opening end side of the female screw section 26 and having an inner diameter larger than the female thread valley diameter of the female thread portion 26 A front end hole 28 having an end-side counterbore portion 25 is formed, and a male end that can be screwed into a female screw portion 26 is formed at a relative end portion of the bolt body 21 or the other side of the pad 22 (pad 22 in FIG. 1). A screw portion 31, a groove portion 32 having an outer diameter smaller than the female thread of the female screw portion adjacent to the proximal end side of the male screw portion 31, and an open end adjacent to the proximal end side of the groove portion 32 A step having an outer diameter substantially the same as or slightly smaller than the inner diameter of the side spot facing portion 25 Mating end 29 and a 33 are formed.

  According to the tightening bolt structure 20, the pad 22 can be attached to and detached from the bolt body 21 at the first relative axial direction position (FIG. 2) where the female screw portion 26 and the male screw portion 31 are screwed together. In the second relative axial direction position (FIG. 3) in which the male screw portion 31 is loosely fitted in the counterbore portion 27 and the female screw portion 26 is loosely fitted in the groove portion, the pad 22 is a bolt body. 21 is rotatable relative to 21. Therefore, if the fastening bolt structure 20 is used at the second relative axial position where the pad 22 is mounted so as to be relatively rotatable with respect to the bolt body 21, the pad 22 is used as the engaged surface of the suspended object. Even if the tightening bolt structure 20 is rotated and tightened while being pressed, the rotational force is absorbed by the pad 22 and does not act on the suspended object, so that the suspended object can be lifted in a stable posture without rotating. be able to. Further, when the pad 22 is worn, the pad 22 can be removed and a new pad can be attached at the first axial position where the female screw portion 26 and the male screw portion 31 are screwed together.

Japanese Patent No. 36551493

  As described above, the tightening bolt structure disclosed in Patent Document 1 is extremely advantageous, but has some problems in actual handling. That is, when the pad 22 is inserted into the tip hole 28 of the bolt body 21, grease is sealed in the entire surface of the tip hole 28, and then the male screw portion 31 is screwed into the female screw portion 25 to make the first relative By setting the axial position (FIG. 2) and rotating the pad 22 in this state, the second relative axial position (FIG. 3) is finally obtained and the pad 22 is rotated relative to the bolt body 21. When the pad is advanced toward the back toward the second relative axial position after the first relative axial position is obtained, the back seat of the tip hole 28 can be freely set. Since there is no way for the air and grease collected in the counterbore 27 to escape, a damper state occurs in which the screwed pad 22 attempts to return. This makes it difficult to mount the pad 22 and requires time.

  The above problem can be alleviated if the amount of grease sealed in the tip hole 28 is reduced, but the air damper action is caused by gradually compressing the air accumulated in the sealed space of the back spot facing portion 27. Cannot be avoided, and cannot be a fundamental solution for facilitating the mounting of the pad 22. Also, if the amount of grease is small, there is a risk that the pad 22 will rotate freely with respect to the bolt body 21 at the second relative axial position (FIG. 3) (so-called grease breakage). As a result, rust is likely to be generated at the contact points, and the life of the pad 22 and the bolt body 21 is shortened.

  Further, when the worn pad 22 is replaced, when the pad 22 is to be pulled out from the second relative axial position (FIG. 3) through the first relative axial position (FIG. 2), Since a reduced pressure or vacuum state is formed in the spot facing portion 27, the operation of pulling out the pad 22 is not easy.

  Therefore, the problem to be solved by the present invention is to further improve the tightening bolt structure proposed in Patent Document 1 to facilitate the attachment / detachment operation of the pad with respect to the bolt body.

In order to solve this problem, the present invention according to claim 1 is directed to a clamp body having a pair of opposing legs, receiving means provided on one of the pair of legs, and being able to advance and retract to the other leg. A screw-type clamp of a type that includes a tightening bolt structure that is fastened and fixed between the suspended bolt and the receiving means by moving the tightening bolt structure close to the receiving means. The attached bolt structure is composed of a bolt body and a pad having tip engagement teeth that are attached to the tip of the bolt body so as to be relatively rotatable and detachable. A tip hole having a counterbore portion adjacent to the back portion of the screw portion and a tip side counterbore portion adjacent to the tip end side of the female screw portion is formed, and a tip portion facing the bolt body tip portion of the pad is formed. Of the tip hole An engagement end portion having a male screw portion that can be screwed to the screw portion, a groove portion adjacent to the distal end side of the male screw portion, and an enlarged diameter portion adjacent to the distal end side of the groove portion is formed. The pad can be attached to and detached from the bolt body at the first relative axial position where the male threaded portion of the joint end is screwed with the female threaded portion of the tip hole of the bolt body, and the engagement end of the pad is The male threaded portion, groove portion and expanded diameter portion of the engagement end portion of the pad are inserted further into the distal end hole from the first relative axial position, and the counterbored portion, female thread portion and distal end of the distal end hole The pad is rotatable relative to the bolt body at the second relative axial position respectively accommodated in the side counterbore part, and further extends radially from the counterbore part of the tip hole of the bolt body. Ri Na and air vent holes opening at the outer peripheral surface of the bolt body is formed, the air The punching hole discharges the air accumulated in the counterbored portion of the tip hole when the pad is inserted into the bolt body to obtain the second relative axial position, and is discharged to the outside of the tightening bolt structure. When the pad located at the second relative axial position is pulled out from the bolt body, it functions as an air injection hole for injecting air from the outside of the tightening bolt structure into the counterbore part of the tip hole. It is possible to replenish grease using

  According to the present invention, in the tightening bolt structure having the configuration described in Patent Literature 1, the air vent hole for communicating the counterbore portion of the tip hole with the outside of the tightening bolt structure at the second relative axial position. Therefore, when the pad is inserted into the tip hole of the bolt body, the air accumulated in the counterbore part is smoothly discharged from the air vent hole to the outside of the tightening bolt structure. Installation work is easy. When removing a worn pad to replace it, air enters the counterbore part from the outside of the tightening bolt structure through the air vent hole, so that a vacuum or vacuum state is formed in the counterbore part. It is easy to remove.

  Furthermore, grease can be replenished using this air vent hole, and if a wire or the like is inserted into this air vent hole, the grease sealing state (grease amount) in the counterbore part can be easily confirmed. It is also convenient when performing grease-up as maintenance.

It is a half sectional view which shows the fastening bolt structure in the screw type clamp of patent documents 1 in the state where the pad was removed from the bolt main part. FIG. 6 is a one-side cross-sectional view showing a first relative axial position relationship in which the male screw portion of the pad is screwed into the female screw portion of the tip hole of the bolt body in the tightening bolt structure. FIG. 6 is a one-side cross-sectional view when the pad is in a second relative axial position relationship in which the pad is rotatably attached to the bolt body in the tightening bolt structure. It is a front view of the screw type clamp by the example of the present invention incorporating the bolt structure which improved this bolt structure. It is a bottom view of this screw type clamp. It is a side view of this screw type clamp. It is sectional drawing which shows the clamp | bolt bolt structure incorporated in this screw type clamp in the state from which the pad was removed from the bolt main body.

  Several embodiments of the present invention will be described below in detail with reference to the accompanying drawings. However, the present invention is not limited to these embodiments, and is within the scope of the invention defined by the description of the scope of claims. It goes without saying that various modifications and changes are allowed in the above.

  4 to 7 show a screw-type clamp according to an embodiment of the present invention. The overall configuration of the screw-type clamp 10 is conventionally known. As described above as the background art, one of the pair of opposed legs 11a and 11b (11b) of the clamp body 11 has a swivel jaw as a metal receiver. 12 is rotatably and swingably supported, and the other leg portion (11a) is provided with a bolt main body 21 of the tightening bolt structure 20 so as to advance and retreat. In the screw-type clamp 10 having such a configuration, an end of a suspended object (not shown) is inserted into the opening 13 between the pair of legs 11a and 11b, and a handle 14 attached to the rear end of the bolt body 21 is provided. By rotating and moving the clamping bolt structure 20 in the clamping direction (left direction in FIG. 4), the suspended object is sandwiched between the swiveling jaw 12 and the pad 22 at the tip of the clamping bolt structure 20. Fixed.

  Since the feature of the present invention resides in the fastening bolt structure 20 in the screw clamp 10, the description of other components will be omitted, and the fastening bolt structure 20 will be further illustrated in FIG. It will be described in detail with reference. In addition, about the component of the fastening bolt structure 20, the same code | symbol is attached | subjected to the element which is the same as that shown in FIG. 1 thru | or FIG.

  The tightening bolt structure 20 includes a bolt main body 21 and a pad 22 that is relatively rotatably and detachably attached to the tip of the bolt main body. The bolt body 21 is formed in a substantially cylindrical shape from, for example, special alloy steel, and a male screw 23 is formed on the outer peripheral surface thereof. A handle mounting hole 24 for attaching the handle 14 is formed through the rear end portion of the bolt body 21.

  In this embodiment, the pressure nut 16 is slidably and non-rotatably mounted in the axial direction by the rotation stop pin 36 while being biased by the spring 17 in the mounting hole 15 formed through one leg portion 11a of the clamp body 11. The pressure nut 16 is provided so that the bolt body 21 can be passed through. The tip 18 of the pressure nut 16 protrudes into the clamp opening 13, but when the tightening bolt structure 20 is tightened with the suspended object sandwiched between the swivel jaw 12 and the pad 22, the spring The pressure nut 16 gradually retracts (to the right in FIG. 4) against the urging force of 17. A tightening confirmation ring 19 is provided around the tip 18, and when the pressure nut 16 is retracted until the tightening confirmation ring 19 disappears, it can be confirmed that a prescribed tightening force has been applied. it can. Since the configuration and operation of the pressure nut 16 and the tightening confirmation ring 19 are described in detail in Japanese Patent Application Laid-Open No. 10-037919 by the applicant of the present application, further explanation is omitted here.

  The front end of the bolt body 21 has a counterbore portion 25 having a circular cross section that opens toward the front end, a female screw portion 26 adjacent to the back thereof, and a counterbore portion 27 having a circular cross section adjacent to the back thereof. A tip hole 28 is formed. In this embodiment, the inner diameter R1 of the tip side counterbore part 25 is set larger than the valley diameter R2 of the female thread part 26, and the inner diameter R3 of the rear counterbore part 27 is substantially the same as or equal to the valley diameter R2 of the female thread part 26. Is set slightly larger than. Further, an air vent hole 35 extending in the radial direction of the bolt main body 21 from the back spot facing portion 27 is formed and opened at the outer peripheral surface 21 a of the bolt main body 21.

  The pad 22 is made of, for example, special alloy steel, and is integrally formed from an engagement end 29 that is inserted and fitted into the tip hole 28 of the bolt body 21 and a tip 30 that has a larger diameter than the engagement end 29. Configured. An engagement tooth 34 such as a knurled shape is formed on the distal end surface of the distal end portion 30 of the pad 22.

  The engagement end portion 29 of the pad 22 includes a male screw portion 31 provided at a base end portion facing the bolt main body 21, a groove portion 32 adjacent to the distal end side, and an expanded diameter portion 33 adjacent to the distal end side. Have The male threaded portion 31 can be screwed with the female threaded portion 26 of the tip hole 28 of the bolt body 21. Accordingly, the crest diameter R4 is substantially the same as the trough diameter R2 of the female thread portion 26 of the tip hole 28. The outer diameter R5 of the groove portion 32 is set to be the same as or slightly smaller than the crest diameter of the female screw portion 26 of the tip hole 28 of the bolt body 21, and the outer diameter R6 of the step portion 33 is set to the tip hole of the bolt body 21. 28 is set to be substantially the same as or slightly smaller than the inner diameter R1 of the front end side spot facing portion 25. Further, the bolt body 21 and the pad 22 are set in a second relative position, which will be described later, by appropriately setting the axial length of each part of the tip hole 28 of the bolt body 21 and each of the engagement end parts 29 of the pad 22. When there is a relative axial position, the male threaded portion 31, the groove 32, and the expanded diameter portion 33 of the engagement end 29 of the pad 22 are the counterbore 27 of the tip hole 28 of the bolt body 21, and the female threaded portion 26. And the tip side counterbore part 25.

  The operation of attaching the pad 22 to the bolt body 21 is performed by inserting the engaging end portion 29 of the pad 22 into the tip hole 28 of the bolt body 21. Since the inner diameter R1 of the tip side counterbore portion 25 of the bolt body tip hole 28 is larger than the crest diameter R4 of the male thread portion 31 of the pad engagement end portion 29, the engagement end portion 29 of the pad 22 is made to be the tip hole of the bolt body 21. 28, and the inner diameter R1 is substantially the same as or slightly smaller than the outer diameter R6 of the stepped portion 33 of the pad engaging end 29, so that positioning is automatically performed (center alignment). Is done.

  The pad engaging end 29 is inserted into the bolt body tip hole 28 while being guided / positioned in this manner, whereby the first relative axial position where the male screw portion 31 and the female screw portion 26 are screwed together. A relationship is obtained (see FIG. 2). By screwing the pad 22 in this positional relationship, the pad engagement end portion 29 is inserted further into the bolt main body tip hole 28, and finally, the male screw portion 31 of the female screw portion 26 of the bolt main body tip hole 28 is inserted. A second relative axial direction positional relationship is obtained that leaves the region and is accommodated in the counterbore portion 27 located at the innermost position (see FIG. 3). In this positional relationship, the male thread portion 31, the groove portion 32, and the step portion 33 of the pad engaging end portion 29 are respectively connected to the tip hole of the bolt main body 21 according to the relationship between the diameter dimension and the axial length dimension of each portion as described above. 28 is rotatably accommodated in the counterbore portion 27, the female screw portion 26, and the counterbore portion 25, and thus the pad 22 is rotatable with respect to the bolt body 21.

  When the pad is mounted, when the insertion is performed further from the first relative axial direction position where the male thread portion 31 and the female thread portion 26 are screwed together toward the second relative axial position, The grease or air previously sealed in the tip hole 28 accumulates in the counterbore portion 27 and is gradually compressed. Since it is formed, grease and air that accumulates in the counterbore portion 27 are smoothly discharged to the outside of the bolt main body 21 through the air vent hole 35, so that the pad mounting operation is not hindered.

  After obtaining the fastening bolt structure 20 in which the pad 22 is mounted in the second relative axial position relative to the bolt body 21 as described above, the pad 22 is inserted from the outside of the leg portion 11a of the clamp body 11. Then, the male screw 23 on the outer peripheral surface of the bolt main body is screwed into the pressure nut 16, and the handle 15 is operated in this state to rotate the bolt main body 21, whereby the tightening bolt structure 20 is fixed to the leg portion 11 a of the clamp main body 10. Attached to. Of course, after the bolt body 21 is mounted on the leg portion 11a alone, the pad 22 may be mounted from the side of the clamp opening 13 as described above to form the tightening bolt structure 20.

  When it is necessary to replace the pad 22 due to wear of the engaging teeth 34 at the tip of the pad 22, the male thread portion 31, the groove portion 32 and the expanded diameter portion 33 of the engaging end portion 29 of the pad 22 are connected to the bolt body. The direction in which the pad 22 is pulled out from the bolt body 21 from the second relative axial position in the state of being accommodated in the counterbore portion 27, the female screw portion 26, and the tip side counterbore portion 25 of the tip hole 28 of the tip 21. Move to. As a result, a first relative axial position in which the male threaded portion 31 of the engagement end portion 29 of the pad 22 is screwed into the female threaded portion 26 of the tip hole 28 of the bolt body 21 is obtained. What is necessary is just to make it detach | leave from the bolt main body 21 by turning to a direction. At this time, the inside of the counterbore part 27 is depressurized. However, since air is automatically introduced from the outside through the air vent hole 35, the work of pulling out the pad 22 is not hindered. That is, the air vent hole 35 functions as an air injection hole during the pad drawing operation. Since the operation of attaching a new pad 22 after removing the worn pad 22 can be performed in the same manner as described above, the description is omitted.

  Furthermore, grease can be replenished using the air vent hole 35. If a wire or the like is inserted into the air vent hole 35, the grease sealing state (grease amount) in the counterbore portion 27 can be easily confirmed. If the grease amount is insufficient, the grease is passed through the air vent hole 35 to the counterbore portion 27. The grease can be replenished and replenished, and the air vent hole 35 can be used effectively during maintenance.

10 Screw type clamp 11 Clamp main body 11a, 11b Leg part 12 Rotating jaw (receiver)
13 Opening 14 Handle 15 Mounting hole 16 Pressure nut 17 Spring 18 Pressure nut tip 19 Tightening confirmation ring 20 Tightening bolt structure 21 Bolt body 21a Outer peripheral surface 21b Rear end surface 22 Pad 23 Male screw 24 Handle mounting hole 25 Tip side Counterbore part 26 Female thread part 27 Back counterbore part 28 End hole 29 Engagement end part 30 End part 31 Male thread part 32 Groove part 33 Expanded diameter part 34 Engagement tooth
35 air vent

Claims (1)

A clamping bolt structure comprising: a clamp main body having a pair of opposing leg portions; receiving means provided on one of the pair of leg portions; and a fastening bolt structure provided on the other leg portion so as to be able to advance and retract. In the screw-type clamp that is fastened and fixed between the suspended object and the receiving means by moving the receiving object close to the receiving means, the tightening bolt structure is relative to the bolt body and the tip of the bolt body. It is composed of a pad having a tip engagement tooth that is rotatably and detachably attached, and has a female screw portion, a counterbore portion adjacent to the back of the female screw portion, and a female screw portion at the tip portion of the bolt body And a male screw that can be screwed into the female screw portion of the tip hole at the tip portion facing the bolt body tip portion of the pad. And the tip of the male thread An engagement end portion having an adjacent groove portion and an expanded diameter portion adjacent to the distal end side of the groove portion is formed, and the male screw portion of the engagement end portion of the pad is screwed with the female screw portion of the tip hole of the bolt body. The pad is detachable from the bolt body at the first relative axial position to be joined, and the engagement end portion of the pad is inserted further into the tip hole from the first relative axial position. The pad at the second relative axial position where the male threaded portion, groove portion and expanded diameter portion of the engagement end portion of the pad are respectively accommodated in the counterbore portion, female screw portion and tip side counterbore portion of the tip hole. is rotatable relative bolt body, further, Ri Na and air vent holes opening at the outer peripheral surface of the bolt body is formed to extend from the deeper pocket portion of the distal end hole of the bolt body in the radial direction, said air vent The hole is formed by inserting the pad into the bolt body and When the relative axial direction position is obtained, the air accumulated in the counterbored portion of the tip hole is discharged to the outside of the tightening bolt structure, and the pad at the second relative axial position is removed from the bolt body. When pulling out, it functions as an air injection hole for injecting air from the outside of the tightening bolt structure into the counterbore part of the tip hole, and it is possible to replenish grease using this air release hole. Screw type clamp.

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