Joint

Abstract

To provide a joint which has a good appearance while inhibiting deterioration of strength.SOLUTION: A joint 1 includes: an annular joint main part 10 having an opening 11; and a closing member 20. The joint main part 10 includes: an attachment part 13 provided at a portion opposite to the opening 11; and connection recessed parts 14 including two end faces 12 with the opening 11 therebetween, first recessed parts 14a recessed from the respective end faces 12, and second recessed parts 14b recessed from the respective first recessed parts 14a. The closing member 20 includes: a rod-like closing part 21 inserted into the opening 11; connection protruding parts 22 having first protruding parts 22a respectively protruding from respective ends of the closing part 21, and second protruding parts 22b protruding from the respective first protruding parts 22a; a beam part 23 extending from the closing part 21 and attached to the attachment part 13 at its tip; and reinforcement pieces 24 each connecting the first protruding part 22 with the beam part 23.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a joint for connecting chains or ropes. [Background technology]

[0002] A known joint for connecting chains or ropes is a metal rod bent into a ring shape with an opening formed between its two end faces (a so-called "split link"). When using this split link to connect chains, the chain is passed through the opening, the two end faces are brought close together so that they face each other, and the opening is closed; the end faces are then welded together to join the chains.

[0003] However, when split cans are used, welding is required and the weld bead must be polished after welding, which is a time-consuming process.

[0004] Incidentally, a joint has been proposed that includes a C-shaped main body having an opening and a T-shaped closure member attached to the main body so as to close the opening (Patent Document 1). More specifically, the main body has outwardly protruding convex portions at each end on both sides of the opening, and a recessed attachment portion is provided in the main body at a portion opposite the opening (the middle portion of the C-shape). Meanwhile, the closure portion has a rod-shaped closure portion that has recesses at both ends into which the convex portions of the main body are inserted and that closes the opening, and a rod-shaped beam portion that extends from the center of the closure portion into the attachment recess.

[0005] According to the technology of Patent Document 1, the engagement between the convex part of the main body and the concave part of the closure member prevents the opening of the opening when the main body is pulled by the connected chain, and the insertion of the tip of the beam part of the closure member into the mounting concave part of the main body and mounting with a pin prevents the closure member from coming off the main body. This means that, compared to split cans, there is no need for welding and the chain can be easily connected.

[0006] However, in the technology of Patent Document 1, the recess of the closing member is adapted to receive the protrusion protruding from the end of the main body, which inevitably means that the outer diameter of the closing member is larger than the outer diameter of the end of the main body, causing the closing member to protrude outward from the main body, which poses the problem of the closing member protruding from the main body getting caught on other components and also leads to poor appearance of the joint.

[0007] Therefore, it is conceivable to make the outer diameter of the main body within a predetermined range from the end smaller than the outer diameter of the other parts, and to provide a protrusion at the tip of that end that protrudes smaller than the outer diameter of the other parts, and then to make the outer diameter of the closing part the same size as the outer diameter of the other parts of the main body and to provide a recess into which the protrusion can be inserted, so that the closing part does not protrude beyond the main body. However, in this case, since the outer diameter of the part with the protrusion is smaller than the original outer diameter, there is a problem that the strength when pulled by the connected chain is reduced. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] Publication No. 51-141760 Summary of the Invention [Problem to be solved by the invention]

[0009] In view of the above circumstances, an object of the present invention is to provide a joint that has a good appearance while suppressing a decrease in strength. [Means for solving the problem]

[0010] In order to solve the above problems, the joint according to the present invention comprises: "A joint comprising an annular joint body having an opening, and a closing member attached to the joint body and closing the opening, The joint body is an attachment portion provided at a location on the opposite side of the opening with the center of the annulus in between; a connecting recess having a first recess recessed from each of two end faces sandwiching the opening and penetrating in a direction connecting the opening and the mounting portion, and a second recess recessed from a portion of the first recess away from the end faces and open at least to the opposite side from the mounting portion, The closure member is a rod-shaped closing portion that is inserted into the opening portion so as to connect the two end surfaces of the joint body, and whose outer surface coincides with an extension of an outer surface of a portion of the joint body where the connecting recess is provided; a connecting protrusion having first protrusions protruding from both ends of the closing portion and inserted into the first recess, and a second protrusion protruding from the first protrusions and inserted into the second recess; a beam portion extending from the closing portion to the mounting portion and having a tip attached to the mounting portion; a reinforcing piece that connects the first protrusion and the beam and is provided on the same plane as the first protrusion. It is characterized by:

[0011] For example, when connecting two chains with this configuration, with the joint body and the closure member separated, the loops of each chain are passed through the opening of the joint body, and the two chains are separated in the direction that the two end faces move apart across the opening. In this state, the connecting protrusion of the closure member is inserted into the connecting recess of the joint body, and the tip of the beam portion of the closure member is attached to the mounting portion of the joint body for assembly. This closes the opening of the joint body with the closure member of the closure member, connecting the two chains. On the other hand, if the connected chains are designed to be removable, the chains can be removed by releasing the attachment between the mounting portion and the tip of the beam portion and separating the joint body and the closure member.

[0012] According to this configuration, when the joint body and the closure member are assembled, the connecting protrusions provided on both ends of the closure portion of the closure member are inserted into the two connecting recesses provided on the joint body, respectively. This allows the connecting recesses and connecting protrusions to engage with each other, preventing deformation that would separate the two end faces (opening of the opening). Furthermore, even if the joint is pulled or twisted by the connected chain, the structure makes it difficult for a direct force to be applied in the direction of removing the closure member, and because the opening is closed by the closure portions, the chain will not come loose from the joint body.

[0013] Furthermore, when assembled, the outer surface of the closure part coincides with the extension of the outer surface of the part of the joint body where the connecting recess is provided, so there is no step between the joint body and the closure part, there is no risk of other parts getting caught, and the joint has a good appearance similar to that of a split can.

[0014] In addition, the tip of the beam extending from the closing part that closes the opening is attached to the attachment part on the opposite side of the joint body from the opening, so the beam separates the loop of the joint body into two, preventing the connected chains from getting too close and interfering with each other.

[0015] Furthermore, in the closure member, the first protrusion of the connecting protrusion and the beam portion are connected by a flat reinforcing piece, which reinforces the first protrusion. This allows the reinforcing piece to reduce the plate thickness of the first protrusion while maintaining the strength of the connecting protrusion. Meanwhile, on the joint body side, reducing the plate thickness of the first protrusion of the closure member also allows the first recess of the connecting recess into which the first protrusion is inserted to be reduced. Furthermore, reducing the first recess relatively increases the thickness of the portion of the joint body where the connecting recess is provided, thereby preventing a decrease in strength at that portion. Therefore, by setting the plate thickness of the first protrusion of the connecting protrusion of the closure member to an appropriate thickness, a decrease in the connection strength between the connecting recess and the connecting protrusion can be prevented without creating a step between the joint body and the closure member.

[0016] In the technology of Patent Document 1, when forming the protrusions and recesses so that the closing portion does not protrude beyond the main body, it is conceivable to suppress a decrease in strength by thinning the wall thickness of the recessed portion of the closing member and providing a reinforcing piece connecting to the beam portion at the recessed portion. However, in this case, since a space is required in the closing member for the protrusions to pass through, the reinforcing piece is provided at both outer portions of the protrusions, resulting in a problem that the thickness of each reinforcing piece is thin and prone to breakage when a chain inserted into the main body loop collides with it. Furthermore, the space formed between the two reinforcing pieces may become caught in this space with other components. To address these problems, the joint of this configuration provides a connecting recess in the joint main body and a connecting protrusion in the closing member. Therefore, only one reinforcing piece is required to pass through the recess, allowing the reinforcing piece to have sufficient thickness and be less likely to break when a chain collides with it. Furthermore, since no space is formed at the reinforcing piece and it is located inside, it does not catch on other components. [Effects of the Invention]

[0017] As described above, according to the present invention, a joint that has a good appearance while suppressing a decrease in strength can be provided. [Brief explanation of the drawings]

[0018] [Figure 1] FIG. 2A is a perspective view showing the joint of the first embodiment from the front side, FIG. 2B is a perspective view showing the joint of FIG. 2A from the rear side, and FIG. 2C is an exploded perspective view of the joint of FIG. [Figure 2] (a) is a plan view of the joint of the first embodiment, (b) is an enlarged cross-sectional view showing the main part taken along line AA in (a), (c) is an enlarged cross-sectional view taken along line BB in (a), and (d) is an enlarged cross-sectional view taken along line CC in (a). [Figure 3] (a) is an explanatory diagram showing the attachment relationship between the attachment portion and the beam portion in the joint of Figure 1, (b) is an explanatory diagram showing an attachment relationship between the attachment portion and the beam portion that is different from (a), (c) is an explanatory diagram showing an attachment relationship between the attachment portion and the beam portion that is different from (a) and (b), and (d) is an explanatory diagram showing an attachment relationship between the attachment portion and the beam portion that is different from (a) to (c). [Figure 4] 10(a) is a perspective view of a joint according to a second embodiment, (b) is an exploded perspective view of the joint in (a), and (c) is a plan view of the joint in (a). [Figure 5] FIG. 10(a) is a perspective view of a joint according to a third embodiment, and FIG. 10(b) is an exploded perspective view of the joint of FIG. [Figure 6] 10(a) is an exploded perspective view of a joint according to a fourth embodiment, FIG. 10(b) is an exploded perspective view of a joint according to a fifth embodiment, and FIG. 10(c) is an exploded perspective view of a joint according to a sixth embodiment. [Figure 7] FIG. 10A is an exploded perspective view of a joint of a seventh embodiment, FIG. 10B is a perspective view showing the joint of FIG. 10A in an assembled state, and FIG. 10C is an explanatory diagram showing a cross section of the attachment portion between the attachment portion and the beam portion in FIG. 10B. DETAILED DESCRIPTION OF THE INVENTION

[0019] A joint 1 according to a first embodiment of the present invention will now be described in detail with reference to Figures 1 and 2. The joint 1 comprises a C-shaped, i.e., an annular joint body 10 having an opening 11, and a closing member 20 attached to the joint body 10 and closing the opening 11.

[0020] In the following description, the direction in which the two end faces 12 of the joint body 10 separated by the opening 11 is referred to as the first direction, the direction connecting the opening 11 and the part opposite the opening 11 across the annular center of the joint body 10 is referred to as the second direction, and the direction perpendicular to the first and second directions is referred to as the third direction (see Figure 1(c)).

[0021] The joint body 10 has an overall C-shape, formed by bending a round rod of a predetermined wire diameter into a U-shape at two locations. The joint body 10 includes an attachment portion 13 provided on the side opposite the opening 11 across the center of the annulus, connecting recesses 14 recessed in each of the two end faces 12, and a through hole 15 passing through the joint body 10 toward the attachment portion 13. The through hole 15 passes through the attachment portion 13 in the second direction at the center of the attachment portion 13 in the first direction.

[0022] The attachment portion 13 is formed as a groove recessed in the second direction from the inward-facing surface on the outer circumferential surface of the joint body 10. The groove of the attachment portion 13 extends with a constant width in the first direction, longer than the distance between the two end faces 12. The length of the attachment portion 13 in the first direction is the same as the distance between the bottoms in the first direction of each of the two first recesses 14a described below.

[0023] The connecting recess 14 has a first recess 14a recessed in the first direction from each end face 12 and penetrating in the second direction, and a second recess 14b recessed in the third direction from a portion of the first recess 14a away from the end face 12. The distance of the first recess 14a in the third direction is the same as the width (length in the third direction) of the groove of the mounting portion 13. The second recess 14b is recessed on both sides in the third direction, with the first recess 14a in between. In this embodiment, the second recess 14b does not penetrate in the second direction and is open only on the side opposite the mounting portion 13. In other words, the end of the second recess 14b near the mounting portion 13 in the second direction is filled with a dam portion 16. This dam portion 16 prevents a decrease in strength at the portion where the connecting recess 14 is provided.

[0024] The connecting recess 14 also has a third recess 14c that is recessed so as to connect the end side of the second recess 14b that is open to the outer surface of the joint body 10 and the end face 12. In the connecting recess 14, the inner wall of the second recess 14b that is closer to the end face 12 is a dovetail wall 14d that is inclined so as to approach the end face 12 the further away from the first recess 14a it is.

[0025] The closure member 20 has a rod-shaped closure portion 21, connecting protrusions 22 protruding from each end of the closure portion 21, a beam portion 23 extending from the closure portion 21, and a flat reinforcing piece 24 connecting the beam portion 23 and the connecting protrusion 22.

[0026] The closing portion 21 is in the form of a cylindrical rod with the same diameter as the wire diameter of the joint body 10 and the same length as the distance between the two end faces 12 of the joint body 10 .

[0027] The connecting protrusion 22 has a flat first protrusion 22a extending from both end faces of the closing portion 21, a second protrusion 22b protruding from the tip of the first protrusion 22a in a direction intersecting the plate surface of the first protrusion 22a, and a third protrusion 22c protruding from the first protrusion 22a so as to connect the closing portion 21 and the second protrusion 22b.

[0028] First protrusion 22a protrudes in the first direction with a width (length in the second direction) that is the same as the diameter of closing portion 21. The thickness of first protrusion 22a is the same as the distance in the third direction of first recess 14a. The outer shape of first protrusion 22a matches the inner shape of first recess 14a.

[0029] The second protrusions 22b protrude in the third direction from both sides of the plate surface of the first protrusion 22a along the tip edge of the first protrusion 22a extending in the second direction. The end face of the second protrusion 22b on the beam 23 side of the tip edge of the first protrusion 22a is provided to a length that does not reach the end edge of the beam 23 side of the first protrusion 22a. Therefore, the end of the second protrusion 22b opposite to the beam 23 side coincides with the extended plane of the outer surface of the closure portion 21, while the end face on the beam 23 side does not coincide with the extended plane of the outer surface of the closure portion 21. The outer shape of the second protrusion 22b coincides with the inner shape of the second recess 14b.

[0030] Third protrusion 22c is provided to connect the end of second protrusion 22b opposite beam 23 to closing portion 21. The outer shape of third protrusion 22c matches the inner shape of third recess 14c. Connecting protrusion 22 is reinforced by third protrusion 22c.

[0031] In the connecting protrusion 22, the wall facing the end face of the closing portion 21 on the outer wall of the second protrusion 22b is a dovetail wall 22d that is inclined so as to approach the closing portion 21 as it moves away from the first protrusion 22a. The dovetail wall 22d of the connecting protrusion 22 is provided to correspond to the dovetail wall 14d of the connecting recess 14.

[0032] Beam portion 23 is formed in a flat plate shape, is provided on the same plane as first convex portion 22a, and extends in the second direction from closure portion 21 with a width equal to the overall length (length in the first direction) of closure portion 21. The plate thickness of beam portion 23 is the same as the plate thickness of first convex portion 22a and is also the same as the width (third direction) of the groove in mounting portion 13 of joint body 10.

[0033] The reinforcing piece 24 is provided on the same plane as the first convex portion 22a and the beam portion 23. The length in the first direction of the beam portion 23 and the reinforcing piece 24 is the length that allows them to be inserted into the attachment portion 13 of the joint body 10 when the closure member 20 is attached to the joint body 10. Therefore, the first convex portion 22a, the beam portion 23, and the reinforcing piece 24 are integrally formed into a single flat plate. Therefore, the tips of the beam portion 23 and the reinforcing piece 24 can be inserted into the attachment portion 13 of the joint body 10.

[0034] In this embodiment, the ends of the beam portions 23 and the reinforcing pieces 24, which are formed as an integral flat plate, are inserted into grooves in the mounting portion 13 of the joint body 10, thereby attaching them to the joint body 10. Hereinafter, the portion of the closure member 20 that is attached to the mounting portion 13 will be simply referred to as the "end of the beam portion 23, etc." In addition, in this embodiment, the fit tolerance between the groove in the mounting portion 13 and the ends of the beam portions 23, etc. is a "transition fit" or "tight fit" relationship that requires hammering or press-fitting. In this embodiment, as shown in FIG. 3(a), the end edges of the beam portions 23, etc. are chamfered to make them easier to insert into the grooves in the mounting portion 13.

[0035] Furthermore, in the present embodiment, as described above, the first convex portion 22a and the beam portion 23 are connected by the reinforcing piece 24 in the closure member 20, and therefore the first convex portion 22a is reinforced by the reinforcing piece 24. As a result, the reinforcing piece 24 makes it possible to reduce the thickness of the first convex portion 22a while maintaining the strength of the connecting convex portion 22. Meanwhile, on the joint body 10 side, as the thickness of the first convex portion 22a in the closure member 20 is reduced, the first recess 14a of the connecting recess 14 into which the first convex portion 22a is inserted can also be reduced. Furthermore, reducing the first recess 14a relatively increases the thickness of the portion of the joint body 10 where the connecting recess 14 is provided, making it possible to suppress a decrease in strength in that portion. For this reason, in the present embodiment, the thickness of the first convex portion 22a is set to a thickness that ensures sufficient strength in the portion of the joint body 10 where the connecting recess 14 is provided.

[0036] The material of the joint 1 (joint body 10 and closing member 20) may be metal, synthetic resin, or nanocellulose.

[0037] Next, we will explain how to use the joint 1. For example, when connecting two chains 2 (see FIG. 2(a)), with the joint body 10 and the closure member 20 separated, the loops of the two chains 2 are passed through the opening 11 of the joint body 10, and then the chains are separated in the first direction with the opening 11 between them. In this state, the closure member 20 is placed in a position on the outside of the opening 11 of the joint body 10 in the second direction, with the tip of the beam portion 23 facing toward the joint body 10 (see FIG. 1(c)).

[0038] Then, the beams 23 and reinforcing pieces 24 are passed through the first recesses 14a so that the connecting protrusions 22 of the closure member 20 are inserted into the connecting recesses 14 of the joint body 10, and the tips of the beams 23 and reinforcing pieces 24 are hammered or press-fit into the grooves of the attachment part 13 to attach the closure member 20 to the joint body 10. At this time, the tips of the beams 23, etc. are inserted until the outer surface of the closure part 21 of the closure member 20 coincides with the extension of the outer surface of the part of the joint body 10 where the connecting recesses 14 are provided. As a result, the opening 11 of the joint body 10 is closed by the closure part 21 of the closure member 20, and the closure member 20 is assembled to the joint body 10, and the two chains 2 are connected.

[0039] On the other hand, when removing the connected chain 2, a rod-shaped tool is inserted into the through-hole 15 and the tip of the beam portion 23 is struck with the tool, moving the closure member 20 so that the tip of the beam portion 23 etc. comes out of the groove of the attachment portion 13, thereby releasing the attachment of the closure member 20 to the joint body 10. This allows the joint body 10 and the closure member 20 to be separated, and the chain 2 can be removed through the opened opening 11. Note that by appropriately setting the fit tolerance between the groove of the attachment portion 13 and the tip of the beam portion 23 etc., it is possible to make it so that the chain 2 cannot be removed without destroying the joint 1, as with a split can, or to make it so that the chain 2 can be removed without destroying the joint 1.

[0040] Thus, according to this embodiment, two chains 2 can be joined by hammering or press-fitting the tips of the beams 23, etc. of the closure member 20 into the grooves of the attachment part 13 of the joint body 10, and the joined chains 2 can be detached by removing the tips of the beams 23, etc. from the grooves of the attachment part 13. Therefore, compared to when a conventional splitter is used, there is no need to weld or polish the weld beads when joining the chains 2.

[0041] Furthermore, according to this embodiment, when the joint body 10 and the closure member 20 are assembled, the connecting protrusions 22 on both ends of the closure portion 21 of the closure member 20 are inserted into the two connecting recesses 14 of the joint body 10, respectively, and the connecting recesses 14 and the connecting protrusions 22 are engaged, so there is no rattle between the joint body 10 and the closure member 20, and deformation such that the two end faces 12 separate from each other (opening of the opening 11) can be prevented when the joint body 10 is pulled in the first direction by the connected chain 2. Furthermore, because the opening 11 is closed by the closure portion 21, the chain 2 will not come off the joint body 10.

[0042] Furthermore, according to this embodiment, when assembled, the outer surface of the closure portion 21 coincides with the extension of the outer surface of the portion of the joint body 10 where the connecting recess 14 is provided, so there is no step between the joint body 10 and the closure portion 21, and there is no risk of other components getting caught.

[0043] Furthermore, according to this embodiment, the tips of the beams 23 and the like extending from the closure section 21 of the closure member 20 are attached to the attachment section 13 on the opposite side of the joint body 10 from the opening 11, so the beams 23 divide the loop of the joint body 10 into two. This prevents the connected chains 2 from getting too close and interfering with each other. Furthermore, because the chains 2 come into contact at the U-shaped curved section of the joint body 10, the contacting sections do not shift and become biased, making it less likely that an impact load will be applied due to the shifting.

[0044] Furthermore, according to this embodiment, the thickness of the first convex portion 22a in the closure member 20 is set to a thickness that provides sufficient strength to the portion of the joint body 10 where the connecting recess 14 is provided, thereby preventing a step from occurring between the joint body 10 and the closure portion 21 and suppressing a decrease in the connecting strength between the connecting recess 14 and the connecting convex portion 22.

[0045] Furthermore, according to this embodiment, the joint body 10 is provided with the attachment portion 13 extending in the first direction, and the beam portion 23 of the closure member 20 attached to the attachment portion 13 is flat, making it difficult for the joint body 10 to twist around the axis extending in the first direction. Furthermore, in this embodiment, the length in the first direction of each of the tips of the attachment portion 13 and the beam portion 23 is the same as the distance between the bottoms in the first direction of the two first recesses 14a, respectively, and is longer than the distance between the two end faces 12 (the width of the opening 11). This increases the strength against torsion compared to when the length is smaller than the width of the opening 11.

[0046] Furthermore, according to this embodiment, in the assembled state, the dovetail wall 14d of the connecting recess 14 and the dovetail wall 22d of the connecting protrusion 22 are engaged with each other, so that deformation in the expanding direction of the first recess 14a can be prevented.

[0047] Furthermore, according to this embodiment, the joint 1 is made up of only two parts, the joint body 10 and the closing member 20, so that an increase in the cost of the joint 1 can be suppressed.

[0048] In the above embodiment, the mounting portion 13 of the joint body 10 is a groove with parallel inner surfaces, and the ends of the beams 23, etc. of the closure member 20 are flat plates with parallel surfaces. However, this is not limited to this. For example, as shown in FIG. 3(b), both the groove of the mounting portion 13 and the ends of the beams 23, etc. may be tapered, and the mounting may be performed by fitting the tapered portions together. Even in this case, by appropriately setting the fit tolerance, it is possible to make the chain 2 either non-detachable or detachable. Alternatively, as shown in FIG. 3(c), the inner wall of the groove-shaped mounting portion 13 may be formed with multiple recesses and protrusions, and the ends of the beams 23, etc. may be tapered to a point with multiple shutter-like claws, and the mounting may be performed by engaging the claws with the recesses and protrusions on the inner wall. Also, as shown in Figure 3(d), a step may be formed on the inner wall of the groove-shaped mounting portion 13 so that the opening side becomes narrower, and the tip of the beam portion 23 etc. may be tapered to a point where the outer shape is discontinuous to form a claw, and the mounting may be performed by engaging the step of the step with the claw.

[0049] Next, an embodiment different from the joint 1 of the first embodiment will be described with reference to Figs. 4 to 7. In the following, the same components as those of the first embodiment will be given the same reference numerals, and detailed description will be omitted. First, a joint 1A of the second embodiment will be described with reference to Fig. 4. The joint 1A includes a joint body 10A and a closure member 20A.

[0050] The length in the first direction of the joint body 10A is shorter than the length in the first direction of the joint body 10 in the joint 1 of the first embodiment. Furthermore, the length in the first direction of the attachment portion 13 of the joint body 10A is the same as the distance between the two end faces 12 with the opening 11 between them. The other configurations of the joint body 10A are the same as those of the joint body 10 of the first embodiment.

[0051] In the closure member 20A, the reinforcing pieces 24 connecting the beam portion 23 and the first protrusion 22a are arranged so that the reinforcing pieces 24 approach the side edges of the beam portion 23 in an arc shape as they move toward the tip side of the beam portion 23. In other words, the reinforcing pieces 24 of the closure member 20A are arranged only in the vicinity of the closure portion 21 and do not extend to the tip of the beam portion 23. The other configurations of the closure member 20A are the same as those of the closure member 20 of the first embodiment.

[0052] The joint 1A of the second embodiment achieves the same effects as the joint 1 of the first embodiment. Furthermore, because the reinforcing piece 24 does not extend along the side edge of the beam portion 23 to its tip, the length in the first direction of the portion spanning between the mounting portion 13 and the closure portion 21 is shorter than the length of the corresponding portion in the joint 1 of the first embodiment. This ensures sufficient space for the chain 2 to pass through even when the length in the first direction of the joint body 10A is short. This allows for a chain with a short length in the first direction to be accommodated, resulting in a joint 1 with a good appearance similar to that of a split chain. Furthermore, according to this embodiment, the wire diameter and outer diameter (lengths in the first and second directions) can be made the same as those of a chain (long link chain) specified in, for example, "JIS F2016," so that the chains can be connected seamlessly.

[0053] Next, a joint 1B of a third embodiment will be described with reference to Fig. 5. The joint 1B includes a joint body 10B and a closing member 20B. The joint body 10B is the same as the joint body 10A of the second embodiment.

[0054] The closure member 20B differs from the closure member 20A of the second embodiment in that the beam portion 23 extends cylindrically from the closure portion 21 in the second direction, and a flat insertion portion 25 is provided at the tip of the beam portion 23 to be inserted into the groove of the attachment portion 13. The insertion portion 25 is formed so that the fit tolerance with the groove of the attachment portion 13 is a "transition fit" or "tight fit." The configuration of other parts of the closure member 20B is the same as that of the closure member 20A of the second embodiment.

[0055] The joint 1B of the third embodiment has the same effects as the joint 1A of the second embodiment. Moreover, since the beam portion 23 of the joint 1B is cylindrical, the rigidity of the joint 1B is higher than that of a flat plate-shaped beam portion, and the strength of the joint 1B is higher than that of the joint 1A.

[0056] Next, a joint 1C of a fourth embodiment will be described with reference to Fig. 6(a). The joint 1C includes a joint body 10C, a closure member 20C, and a mounting screw 30. The joint body 10C has a through hole 15 penetrating in the second direction toward the mounting portion 13, and a counterbore 15a that is larger than the inner diameter of the through hole 15 is provided on the side opposite to the mounting portion 13 (opening 11). The other configurations of the joint body 10C are the same as those of the joint body 10 of the first embodiment.

[0057] The closing member 20C has a threaded hole 26, into which a mounting screw 30 is screwed, provided on the tip surface of the beam portion 23. The other configurations of the closing member 20C are the same as those of the closing member 20 of the first embodiment. In addition, in the fourth embodiment, the fit tolerance between the groove of the mounting portion 13 and the tip of the beam portion 23 etc. is a "loose fit" relationship that allows easy insertion and removal by hand.

[0058] In the joint 1C of the fourth embodiment, the closure member 20C can be attached to the joint body 10C by inserting the tip of the beam portion 23 of the closure member 20C into the groove of the attachment portion 13 of the joint body 10C, and then threading the attachment screw 30 into the screw hole 26 through the through hole 15 and tightening it. In this state, the head of the attachment screw 30 is positioned within the counterbore 15a of the through hole 15 and does not protrude from the outer surface of the joint body 10C. Therefore, there is no risk of other components getting caught on the attachment screw 30, and the appearance of the joint 1C is not impaired. To separate the joint body 10C and the closure member 20C, the attachment screw 30 is removed and the closure member 20C can be easily separated by pulling it in the removal direction.

[0059] The joint 1C of the fourth embodiment provides the same effects as the joint 1 of the first embodiment. In addition, if a screwdriver for turning the mounting screws 30 is available, assembly and disassembly can be easily performed.

[0060] Next, a joint 1D of the fifth embodiment will be described with reference to Fig. 6(b). The joint 1D includes a joint body 10D, a closure member 20D, and an attachment screw 31. In the joint body 10D, a screw hole 17 directed toward the attachment portion 13 penetrates in a direction perpendicular to the plate surface of the flat beam portion 23 (third direction). This screw hole 17 does not penetrate to the opposite side of the attachment portion 13. The other configurations of the joint body 10D are the same as those of the joint body 10 of the first embodiment.

[0061] The closure member 20D has a stopper hole 27 formed at the tip of the beam portion 23 at a position corresponding to the screw hole 17 of the joint body 10D. The open end of the stopper hole 27 is chamfered in the form of a countersunk spot face. The other configurations of the closure member 20D are the same as those of the closure member 20 of the first embodiment. The relationship between the groove of the mounting portion 13 and the tip of the beam portion 23, etc. is a "loose fit" relationship that allows for easy insertion and removal by hand. The mounting screw 31 is a set screw such as a hexagon socket head set screw.

[0062] In the joint 1D of the fifth embodiment, the tip of the beam portion 23 and the like of the closure member 20D is inserted into the groove of the attachment portion 13 of the joint main body 10D to align the screw hole 17 with the stop hole 27, and then the attachment screw 31 is screwed into the screw hole 17 and its tip is inserted into the stop hole 27 of the beam portion 23. This restricts movement of the beam portion 23 in the direction of removal from the attachment portion 13, and the closure member 20D is attached to the joint main body 10D. At this time, by screwing the attachment screw 31 so that a portion of it does not protrude from the screw hole 17, there is no risk of other components getting caught on the attachment screw 31 and the appearance of the joint 1D is not impaired. To separate the joint main body 10D and the closure member 20D, the attachment screw 31 is removed and the closure member 20D can be easily separated by pulling it in the removal direction.

[0063] The joint 1D of the fifth embodiment has the same effects as the joint 1 of the first embodiment. In addition, if a tool such as a hexagonal wrench for turning the mounting screws 31 is available, assembly and disassembly can be easily performed.

[0064] Next, a joint 1E of a sixth embodiment will be described with reference to FIG. 6(c). The joint 1E includes a joint body 10E, a closure member 20E, and a tapered pin 32. The joint body 10E has a through hole 15E that penetrates toward the mounting portion 13 and penetrates to the opposite side in a direction perpendicular to the plate surface of the flat beam portion 23 (third direction). This through hole 15E is a tapered hole. The other configurations of the joint body 10E are the same as those of the joint body 10 of the first embodiment.

[0065] The closure member 20E has a through hole 28 penetrating in the third direction at a position corresponding to the through hole 15E of the joint body 10E on the tip side of the beam portion 23. This through hole 28 is a tapered hole that is continuous with the through hole 15E when aligned with the through hole 15E. The other configuration of the closure member 20E is the same as that of the closure member 20 of the first embodiment. In addition, the relationship between the groove of the mounting portion 13 and the tip of the beam portion 23, etc. is a "loose fit" relationship that allows easy insertion and removal by hand. The tapered pin 32 is shorter in length than the wire diameter of the joint body 10E.

[0066] In the joint 1E of the sixth embodiment, the tip of the beam portion 23 and the like of the closure member 20E is inserted into the groove of the attachment portion 13 of the joint body 10E to align the through hole 15E with the through hole 28, and then the tapered pin 32 is inserted so as to be driven into the through hole 15E. This restricts the movement of the beam portion 23 in the direction of removal from the attachment portion 13, and the closure member 20E is attached to the joint body 10E. At this time, the tapered pin 32 does not protrude from the outer surface of the joint body 10E because its length is shorter than the wire diameter of the joint body 10E. This eliminates the risk of other members getting caught on the tapered pin 32 and does not detract from the appearance of the joint 1E. When separating the joint body 10E and the closure member 20E, a rod-shaped tool is inserted into the through hole 15E from the side opposite to the side where the tapered pin 32 was inserted into the through hole 15E, and the tapered pin 32 is removed by tapping or the like, and then the closure member 20E can be easily separated by pulling it in the direction of removal.

[0067] The joint 1E of the sixth embodiment has the same effects as the joint 1 of the first embodiment. Furthermore, since the tapered pin 32 is inserted into the through hole 15E, the tapered pin 32 is unlikely to come out of the through hole 15E.

[0068] Next, a joint 1F of a seventh embodiment will be described with reference to FIG. 7. The joint 1F includes a joint body 10F, a closure member 20F, and a tool 33 for removing the closure member 20F from the joint body 10F. The attachment portion 13F of the joint body 10F is a hole penetrating in the second direction and has two protrusions 13a protruding inward from the inner surface inside the hole. The two protrusions 13a are provided at the center in the second direction and spaced apart in the first direction. The other configuration of the joint body 10F is the same as that of the joint body 10 of the first embodiment.

[0069] The beam portion 23 of the closure member 20F has, at its tip, two notches 23a recessed from both sides parallel to the second direction, elastic claws 23b protruding from the surface of the notches 23a facing the first direction, and an accommodating recess 23c recessed to accommodate the elastic claws 23b. The notches 23a are cut out at a distance in the second direction equal to the protruding length of the protrusions 13a of the mounting portion 13 in the second direction. The elastic claws 23b are formed to extend outward from the tip side of the beam portion 23 toward the closure portion 21. The elastic claws 23b are arranged so that the distance between the tip of the elastic claws 23b and the surface of the notches 23a facing the second direction is the same as the length of the protrusions 13a of the mounting portion 13F in the second direction.

[0070] The other configurations of the closure member 20F are the same as those of the closure member 20 of the first embodiment. The relationship between the groove of the mounting portion 13F and the tip of the beam portion 23, etc. is a "loose fit" relationship that allows easy insertion and removal by hand.

[0071] The tool 33 has a rod-shaped main body 33a and two release pieces 33b protruding from both ends of the main body 33a. The two release pieces 33b are spaced apart at the same distance as the distance between the two notches 23a at the tip of the beam portion 23. Furthermore, the two release pieces 33b are each formed in the same shape as the space formed by the inner surface of the mounting portion 13F and the outer surface of the notch 23a of the beam portion 23 when the tip of the beam portion 23 is inserted into the mounting portion 13F.

[0072] In the joint 1F of the seventh embodiment, when the tip of the beam 23 or the like of the closure member 20F is inserted into the hole of the mounting portion 13F of the joint body 10F, the elastic claw 23b contacts the protrusion 13a of the mounting portion 13F and deforms to be accommodated in the accommodation recess 23c as the beam 23 moves. Then, when the beam 23 moves and the elastic claw 23b passes the protrusion 13a, the elastic force of the elastic claw 23b causes it to protrude from the accommodation recess 23c and return to its original state. In this state, the protrusion 13a is positioned between the surface of the notch 23a facing the second direction and the elastic claw 23b, and the surface of the notch 23a and the tip of the elastic claw 23b are in contact with the protrusion 13a. In other words, movement of the beam 23 in the second direction is restricted. As a result, the beam portion 23 is restricted from moving further in the direction of insertion into the mounting portion 13F and from moving further in the direction of removal, so that the closure member 20F is attached to the joint body 10F.

[0073] When removing the closure member 20F from the joint body 10F, the two release pieces 33b of the tool 33 are inserted into the space between the mounting portion 13F and the notch 23a in the beam 23, and the elastic claws 23b are pressed by the release pieces 33b and are accommodated in the accommodation recesses 23c. In this state, when the closure member 20F is pulled in the direction of removal, the tips of the beam 23 and the like come out of the mounting portion 13F, and the closure member 20F can be easily separated from the joint body 10F.

[0074] The joint 1F of the seventh embodiment provides the same effects as the joint 1 of the first embodiment.

[0075] The present invention has been described above by citing preferred embodiments, but the present invention is not limited to the above embodiments, and various improvements and design changes are possible as described below, without departing from the spirit of the present invention.

[0076] For example, in the above embodiment, the second recess 14b of the connecting recess 14 is not penetrated in the second direction by the dam portion 16 and is open only on the side opposite the mounting portion 13, but this is not limited thereto and the second recess 14b may penetrate in the second direction and be open on both sides. In this case, it is desirable that the connecting protrusion 22 is formed so that the end face of the second protrusion 22b on the beam portion 23 side is flush with the outer surface of the joint body when inserted into the connecting recess 14 and assembled. This can improve the appearance of the joint.

[0077] Furthermore, in the above embodiment, the connecting recess 14 is provided with a third recess 14c, and the connecting protrusion 22 is provided with a third protrusion 22c, but this is not limited to this, and the third recess 14c and the third protrusion 22c may not be provided.

[0078] Furthermore, in the above embodiment, the tip of the beam portion 23 etc. is inserted into the groove of the mounting portion 13 and attached by hammering, pressing, or screws, etc. However, this is not limited to this, and the mounting portion 13 may be a surface extending in the first direction, and the tip of the beam portion 23 etc. may be provided with a portion that makes surface contact with the surface of the mounting portion 13, and the beam portion 23 may be attached to the mounting portion 13 by mounting screws, set screws, etc. [Explanation of symbols]

[0079] 1st floor joint 10~10F Joint body 11 Opening 12 End face 13 Mounting part 14 Connection recess 14a First recess 14b Second recess 15 through holes 20~20F Closure 21 Closing part 22 Connecting protrusion 22a First convex part 22b Second convex part 23 Beam section 24 Reinforcement piece

Claims

[Claim 1] A joint comprising an annular joint body having an opening, and a closure member attached to the joint body and closing the opening, The joint body is an attachment portion provided at a location on the opposite side of the opening with the center of the annulus in between; a connecting recess having a first recess recessed from each of two end faces sandwiching the opening and penetrating in a direction connecting the opening and the mounting portion, and a second recess recessed from a portion of the first recess away from the end faces and open at least to the opposite side from the mounting portion, The closure member is a rod-shaped closing portion that is inserted into the opening portion so as to connect the two end surfaces of the joint body, and whose outer surface coincides with an extension of an outer surface of a portion of the joint body where the connecting recess is provided; a connecting protrusion having first protrusions protruding from both ends of the closing portion and inserted into the first recess, and a second protrusion protruding from the first protrusions and inserted into the second recess; a beam portion extending from the closing portion to the mounting portion and having a tip attached to the mounting portion; a reinforcing piece that connects the first protrusion and the beam portion and is provided on the same plane as the first protrusion. A joint characterized by:

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