JP2012132517A - Method for preventing loosening up of nut and structure for preventing loosening up of nut - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable sure prevention of looseness of a nut.SOLUTION: An axis 6 having a screw part 63 which screws a nut 7 and a key groove 62a arranged in the vicinity of the screw part 63 is prepared. The nut 7 is screwed in the screw part 63 and a key 64 is engaged with the key groove 62a. An engaging material 8 having a notch 80 which is engaged with the nut 7 to be relatively nonrotatable is prepared and the notch 80 of the engaging material 8 is engaged with the nut 7. A plate 9 having the key groove 9a which is engaged with a through-hole 90 and the key 64 which inserts the axis 6 is prepared, the axis 6 is passed through the through-hole 90 of the plate 9, and the key 64 is engaged with the key groove 9a. Then, the plate 9 is firmly fixed with the engaging material 8 by welding. In this case, the plate 9 is fixed with the nut 7 in conditions that the engaging material 8 is fixed with the nut 7 to be relatively nonrotatable and the plate 9 is fixed with the key groove 62a of the axis 6, so as to prevent loosening up of the nut 7.

Description

  The present invention relates to a locking method and a locking structure that can reliably prevent a nut from locking.

  For example, in Japanese Utility Model Publication No. 7-41932, a plurality of sharp protrusions are provided on the seat surface of the nut, and these protrusions are bitten on the mounting surface of the nut when the nut is tightened. A nut that prevents the nut from rotating (to prevent loosening) is disclosed (see FIGS. 1 to 10 of the publication).

  In the conventional configuration, it is possible to easily prevent the nut from loosening at a low cost, but on the other hand, it is necessary to bite the protrusion provided on the seat surface of the nut into the mounting surface. When it is made of a material with high hardness, it is difficult to reliably prevent the nut from loosening. In the case of a structure in which the mounting surface cannot be excessively pressurized, for example, both ends of the shaft are rotatably supported by the bearing, and the nuts screwed to the tip of the shaft are appropriately tightened so that the bearings at both ends When a moderate pressure is applied to the shaft to smoothly rotate the shaft without backlash, if the nut is tightened excessively in order to bite the protrusion on the nut seat surface, Excessive axial force acts on the bearings at both ends of the shaft, and as a result, rotation of the bearing is hindered, causing a problem that the shaft does not rotate smoothly.

  Therefore, a radial screw hole is formed through the nut, a set screw is screwed into the screw hole, the nut is tightened appropriately, and then the set screw is rotated in the tightening direction to thereby fix the tip of the set screw. It is conceivable to bite into the outer peripheral surface of the shaft, but in this case, if the hardness of the outer peripheral surface of the shaft is high, the tip of the set screw cannot be bitten into the outer peripheral surface of the shaft, and as a result The nut cannot be securely prevented from loosening.

  In this case, if an engagement hole is formed in the outer peripheral surface of the shaft by post-processing in accordance with the position of the set screw, and the tip of the set screw is engaged with the engagement hole, the nut is inserted via the set screw. Although it is possible to prevent loosening, in this case, since it is necessary to form an engagement hole in the outer peripheral surface of the shaft by post-processing, when the shaft is made of a material with high hardness, Post-processing is not easy.

  The present invention has been made in view of such a conventional situation, and the problem to be solved by the present invention is that the nut mounting surface or the shaft is made of a material having a high hardness even when the nut is mounted. The purpose is to ensure that the loosening can be prevented. In addition, the present invention is intended to make it possible to easily prevent the nut from loosening without requiring post-processing in a state where the nut is properly tightened. Furthermore, the present invention attempts to prevent the nut from loosening in a state where the nut is held at an arbitrary rotational position (that is, a tightening position) with respect to the shaft.

The nut locking method according to the invention of claim 1 includes the following steps. That is, i) a step of preparing a shaft having a screw portion to which the nut can be screwed and a key groove disposed in the vicinity of the screw portion, and screwing the nut into the screw portion.
ii) A step of preparing an engaging member having a notch that can be engaged with the nut so as not to be relatively rotatable, and engaging the notch of the engaging member with the nut.
iii) Prepare a plate having a hole through which the shaft can be inserted and a key engaging portion into which a key inserted into the key groove can be engaged, and pass the shaft through the hole in the plate. Engaging the key with the key.
iv) A step of fixing the plate to the engaging member.

  According to the first aspect of the present invention, the plate that engages with the key inserted into the key groove of the shaft is fixed to the engaging member that engages with the nut in a state in which the nut that is screwed into the screw portion of the shaft is tightened. Therefore, the nut is fixed to the shaft via the engaging member, the plate, and the key. Thereby, the nut can be prevented from loosening with respect to the shaft.

  In this case, since it is not necessary to excessively press the seat surface of the nut against the mounting surface, even when the mounting surface of the nut is made of a high hardness material, the nut can be reliably prevented from loosening. Further, since it is not necessary to tighten the nut excessively, it is possible to prevent the nut from being loosened while the nut is properly tightened. Further, since it is not necessary to perform post-processing on the shaft, the nut can be easily and reliably prevented from loosening even when the shaft is made of a material having high hardness. In this case, it is not necessary to position the nut at a predetermined rotational position with respect to the shaft, and the nut can be held at an arbitrary rotational position (that is, a tightening position) with respect to the shaft.

  According to a second aspect of the present invention, in the first aspect, the keyway and the key inserted therein are for attaching a fixing member fixed to the shaft so as not to rotate.

  In this case, a dedicated key groove for a key to be engaged with the key engaging portion of the plate is not formed in advance on the shaft, but a fixed member (for example, a sprocket, a gear, etc. The plate is attached to the shaft using the keyway and the key for the item 5)). Thereby, manufacturing cost can be reduced and the structure can be simplified.

The nut locking method according to the invention of claim 3 includes the following steps. That is, i) a step of preparing a shaft having a screw portion to which a nut can be screwed and a spline or serration arranged in the vicinity of the screw portion, and screwing the nut into the screw portion.
ii) A step of preparing an engaging member having a notch that can be engaged with the nut so as not to be relatively rotatable, and engaging the notch of the engaging member with the nut.
iii) Prepare a plate having a hole through which the shaft can be inserted and a spline hole or serration hole into which the spline or serration can engage, and pass the shaft through the hole in the plate, and the shaft into the spline hole or serration hole in the plate Engaging a spline or serration of the.
iv) A step of fixing the plate to the engaging member.

  According to the invention of claim 3, the plate that engages with the spline or serration of the shaft is fixed to the engaging member that engages with the nut in a state where the nut that is screwed into the screw portion of the shaft is tightened. The nut is fixed to the shaft through the engaging member, the plate, the spline hole (or serration hole) and the spline (or serration). Thereby, the nut can be prevented from loosening with respect to the shaft.

  In this case, since it is not necessary to excessively press the seat surface of the nut against the mounting surface, even when the mounting surface of the nut is made of a high hardness material, the nut can be reliably prevented from loosening. Further, since it is not necessary to tighten the nut excessively, it is possible to prevent the nut from being loosened while the nut is properly tightened. Further, since it is not necessary to perform post-processing on the shaft, the nut can be easily and reliably prevented from loosening even when the shaft is made of a material having high hardness. In this case, it is not necessary to position the nut at a predetermined rotational position with respect to the shaft, and the nut can be held at an arbitrary rotational position (that is, a tightening position) with respect to the shaft.

  According to a fourth aspect of the present invention, in the third aspect, the spline or the serration is for attaching a fixing member fixed to the shaft so as not to rotate.

  In this case, a dedicated spline or serration that engages with the spline hole or serration hole of the plate is not formed on the shaft in advance, but a fixed member (for example, a sprocket or a gear) fixed to the shaft. The plate will be attached to the shaft using the spline or serration for see)). Thereby, manufacturing cost can be reduced and the structure can be simplified.

  According to a fifth aspect of the present invention, in the second or fourth aspect, the fixing member is a sprocket or a gear.

  According to a sixth aspect of the present invention, in the first or third aspect, the notch of the engaging member is provided so as to engage with the outer surface of the nut.

  In this case, the notch of the engaging member engages with the outer surface of the nut, so that the engaging member is attached to the nut so as not to be relatively rotatable.

  According to a seventh aspect of the present invention, in the sixth aspect, the nut is a hexagonal nut, and the outer surface of the hexagonal nut that can engage with the notch of the engaging member is two opposing surfaces of the hexagonal nut.

  In this case, the notch of the engaging member is engaged with the two opposing surfaces of the hexagonal nut, so that the engaging member is attached to the nut so as not to be relatively rotatable. In this case, since the hexagon nut has three sets of opposing surfaces, the engagement member can be engaged with the hexagon nut from any one of the three directions.

  According to an eighth aspect of the present invention, in the first or third aspect, the plate is welded or bonded to the engaging member.

  In this case, since the plate is fixed to the engaging member by welding or adhesion, the plate is securely fixed to the engaging member after the engaging member is engaged with the nut and the plate is attached to the shaft. Can do.

  According to the invention of claim 9, in claim 1 or 3, the shaft is rotatably supported by the bearing, and the nut presses the bearing in the axial direction to smoothly rotate the shaft without rattling. It is a member.

  In this case, by appropriately adjusting the tightening amount of the nut, the shaft can be smoothly rotated without rattling.

  According to a tenth aspect of the present invention, in the first or third aspect, the shaft constitutes a turning portion of an industrial vehicle attachment.

  In this case, the turning unit is a member that turns the attachment in the vertical plane or the horizontal plane. For example, in the swivel part of the C hook attachment of a forklift, the upper and lower parts of the vertical shaft are rotatably supported by bearings. The plate and the engaging member are attached in a state where the pressure is moderately applied. As a result, it is possible to reliably prevent the nut that pressurizes the shaft so as to rotate smoothly without rattling.

  The nut locking structure according to the invention of claim 11 is engaged with a shaft having a threaded portion and a keyway disposed in the vicinity thereof, a nut threadedly engaged with the threaded portion of the shaft, and a non-rotatable engagement with the nut. An engagement member having a notch, a key engagement portion with which a key inserted into a key groove is engaged, and a plate having a hole through which a shaft is inserted, and the plate is fixed to the engagement member .

  According to the eleventh aspect of the invention, the plate that engages with the key that is inserted into the key groove of the shaft is fixed to the engaging member that engages with the nut in a state where the nut that is screwed into the screw portion of the shaft is tightened. Therefore, the nut is fixed to the shaft via the engaging member, the plate, and the key. Thereby, the nut can be prevented from loosening with respect to the shaft.

  In this case, since it is not necessary to excessively press the seat surface of the nut against the mounting surface, even when the mounting surface of the nut is made of a high hardness material, the nut can be reliably prevented from loosening. Further, since it is not necessary to tighten the nut excessively, it is possible to prevent the nut from being loosened while the nut is properly tightened. Further, since it is not necessary to perform post-processing on the shaft, the nut can be easily and reliably prevented from loosening even when the shaft is made of a material having high hardness. In this case, it is not necessary to position the nut at a predetermined rotational position with respect to the shaft, and the nut can be held at an arbitrary rotational position (that is, a tightening position) with respect to the shaft.

  According to a twelfth aspect of the present invention, in the eleventh aspect, the fixing member is fixed to the shaft in a non-rotatable manner via a key inserted into the key groove.

  In this case, a dedicated key groove for a key to be engaged with the key engaging portion of the plate is not formed in advance on the shaft, but a fixed member (for example, a sprocket, a gear, etc. The plate is attached to the shaft using the keyway and the key for the item 15)). Thereby, manufacturing cost can be reduced and the structure can be simplified.

  According to a thirteenth aspect of the present invention, a nut locking structure includes a threaded portion and a shaft having splines or serrations arranged in the vicinity thereof, a nut that is screwed to the threaded portion of the shaft, and a non-rotatably engaged with the nut And a plate having a spline hole or serration hole into which the spline or serration engages and a hole through which the shaft is inserted. The plate is fixed to the engagement member. .

  According to the invention of claim 13, the plate that engages the spline or serration of the shaft is fixed to the engaging member that engages the nut in a state in which the nut that is screwed into the screw portion of the shaft is tightened. The nut is fixed to the shaft through the engaging member, the plate, the spline hole (or serration hole) and the spline (or serration). Thereby, the nut can be prevented from loosening with respect to the shaft.

  In this case, since it is not necessary to excessively press the seat surface of the nut against the mounting surface, even when the mounting surface of the nut is made of a high hardness material, the nut can be reliably prevented from loosening. Further, since it is not necessary to tighten the nut excessively, it is possible to prevent the nut from being loosened while the nut is properly tightened. Further, since it is not necessary to perform post-processing on the shaft, the nut can be easily and reliably prevented from loosening even when the shaft is made of a material having high hardness. In this case, it is not necessary to position the nut at a predetermined rotational position with respect to the shaft, and the nut can be held at an arbitrary rotational position (that is, a tightening position) with respect to the shaft.

  In a fourteenth aspect of the present invention, in the thirteenth aspect, the fixing member is fixed to the shaft so as not to rotate through a spline or a serration.

  In this case, a dedicated spline or serration that engages with the spline hole or serration hole of the plate is not formed in advance on the shaft, but a fixed member (for example, a sprocket or a gear) fixed to the shaft (claim 15). The plate will be attached to the shaft using the spline or serration for see)). Thereby, manufacturing cost can be reduced and the structure can be simplified.

  According to a fifteenth aspect of the present invention, in the twelfth or fourteenth aspect, the fixing member is a sprocket or a gear.

  In the invention of claim 16, in claim 11 or 13, the notch of the engaging member is engaged with the outer surface of the nut.

  In this case, the notch of the engaging member is engaged with the outer surface of the nut, so that the engaging member is attached to the nut so as not to be relatively rotatable.

  According to a seventeenth aspect of the present invention, in the sixteenth aspect, the nut is a hex nut, and the notch of the engaging member is engaged with two opposing surfaces of the hex nut.

  In this case, the notch of the engaging member is engaged with the two opposing surfaces of the hexagonal nut so that the engaging member is attached to the nut so as not to be relatively rotatable. In this case, since the hexagon nut has three sets of opposing surfaces, the engagement member can be engaged with the hexagon nut from any one of the three directions.

  According to an eighteenth aspect of the present invention, in the eleventh or thirteenth aspect, the plate is welded or bonded to the engaging member.

  In this case, since the plate is fixed to the engaging member by welding or adhesion, the plate is securely fixed to the engaging member after the engaging member is engaged with the nut and the plate is attached to the shaft. Can do.

  According to a nineteenth aspect of the invention, in the eleventh or thirteenth aspect, the shaft is rotatably supported by the bearing, and the nut presses the bearing in the axial direction to smoothly rotate the shaft without rattling. It is a member.

  In this case, by appropriately adjusting the tightening amount of the nut, the shaft can be smoothly rotated without rattling.

  According to a twentieth aspect of the present invention, in the eleventh or thirteenth aspect, the shaft constitutes a turning portion of an attachment for an industrial vehicle.

  In this case, the turning unit is a member that turns the attachment in the vertical plane or the horizontal plane. For example, in the swivel part of the C hook attachment of a forklift, the upper and lower parts of the vertical shaft are rotatably supported by bearings. The plate and the engaging member are attached in a state where the pressure is moderately applied. As a result, it is possible to reliably prevent the nut that pressurizes the shaft so as to rotate smoothly without rattling.

  As described above, according to the first aspect of the present invention, the plate engaged with the key inserted into the key groove of the shaft is engaged with the nut in a state where the nut screwed into the screw portion of the shaft is tightened. Since the engaging member is fixed to the mating member, the nut can be fixed to the shaft via the engaging member, the plate, and the key, thereby preventing the nut from loosening with respect to the shaft.

  In this case, it is not necessary to excessively press the nut against the mounting surface, and the nut can be reliably prevented from loosening even when the mounting surface is made of a material with high hardness. Further, it is not necessary to tighten the nut excessively, and the nut can be prevented from loosening with the nut tightened appropriately. Further, since it is not necessary to perform post-processing on the shaft, the nut can be easily and reliably prevented from loosening even when the shaft is made of a material having high hardness. In this case, it is not necessary to position the nut at a predetermined rotational position with respect to the shaft, and the nut can be held at an arbitrary rotational position (that is, a tightening position) with respect to the shaft.

  According to the second aspect of the present invention, the plate that engages the spline or serration of the shaft is fixed to the engaging member that engages the nut in a state in which the nut that is screwed into the screw portion of the shaft is tightened. The nut can be fixed to the shaft through the engaging member, the plate, the spline hole (or serration hole) and the spline (or serration). Thereby, the nut can be prevented from loosening with respect to the shaft.

  In this case, it is not necessary to excessively press the nut against the mounting surface, and the nut can be reliably prevented from loosening even when the mounting surface is made of a material with high hardness. Further, since it is not necessary to tighten the nut excessively, it is possible to prevent the nut from being loosened while the nut is properly tightened. Further, since it is not necessary to perform post-processing on the shaft, the nut can be easily and reliably prevented from loosening even when the shaft is made of a material having high hardness. In this case, it is not necessary to position the nut at a predetermined rotational position with respect to the shaft, and the nut can be held at an arbitrary rotational position (that is, a tightening position) with respect to the shaft.

1 is a side view of a C hook attachment of a forklift that employs a nut locking structure according to an embodiment of the present invention and a guide frame that supports the slidable front and rear direction. FIG. 2 is a front view of FIG. 1. FIG. 3 is a plan view of FIG. 2. It is an internal structure figure of the turning part of C hook attachment (FIG. 1). FIG. 5 is an exploded view of a nut locking structure of a turning part (FIG. 4). It is a figure for demonstrating the assembly procedure of a nut loosening prevention structure (FIG. 5). It is a figure for demonstrating the assembly procedure of a nut loosening prevention structure (FIG. 5).

Embodiments of the present invention will be described below with reference to the accompanying drawings.
1 to 7 are views for explaining a nut locking structure according to an embodiment of the present invention. Here, a forklift is taken as an example of an industrial vehicle, and a case where the nut loosening prevention structure according to the present invention is employed in the turning portion of the C hook attachment of the forklift will be described as an example. 1 and 4, the left side is the vehicle front side, and the right side is the vehicle rear side.

  As shown in FIG. 1 and FIG. 2, the forklift 1 has a C hook attachment 2 as an attachment which is a working device disposed on the front surface portion thereof. The C hook attachment 2 is a C-shaped (or U-shaped) member in side view provided on both the left and right sides of the front portion of the vehicle, and is an upper and lower portion extending portion that is disposed on the upper and lower portions and extends in the horizontal direction. 2A and 2B, and the hanging part 2C which connects these in the up-down direction.

  The C hook attachment 2 is suitable for, for example, handling a coil material obtained by winding a steel sheet for an automobile body into a roll shape. In this case, the lower extending portion 2B of the C hook attachment 2 is passed through the central hole of the coil material, so that the coil material is suspended and the cargo handling operation is performed.

  The upper extending portions 2A of the left and right C hook attachments 2 are connected to left and right support frame assemblies 3, 3 'provided corresponding to the respective C hook attachments 2, respectively.

  The left support frame assembly 3 has a pair of stays 30 and 31 that are arranged at intervals in the front-rear direction (left-right direction in FIG. 1) and extend in the up-down direction. It is fixed to the upper extension 2A of the attachment 2. Each stay 30, 31 is inserted with a support shaft 32 extending in the horizontal direction along the extending direction of the upper and lower extending portions 2 </ b> A, 2 </ b> B of the C hook attachment 2. The support shaft 32 is supported by a frame 33 provided between the stays 30 and 31. Each stay 30, 31 is rotatable around the axis of the support shaft 32.

  The support frame assembly 3 also includes frames 34 and 35 that are disposed between the stays 30 and 31 at intervals in the front-rear direction and extend in the left-right direction (left-right direction in FIG. 2). The frames 34 and 35 are integrally connected to the frame 33.

  A cylinder 4 is provided corresponding to the support frame assembly 3. The piston rod 40 of the cylinder 4 is hinged to a flange 30 a provided at the upper end of the stay 30.

  With this configuration, when the piston rod 40 of the cylinder 4 is extended or retracted, the C hook attachment 2 swings around the axis of the support shaft 32 via the stays 30 and 31 (see the one-dot chain line in FIG. 2). ).

  The right support frame assembly 3 ′ has the same configuration as the left support frame assembly 3, and corresponding members are denoted by the same reference numerals. The piston rod 40 ′ of the cylinder 4 ′ is hinged to a flange 31 a ′ at the upper end of the stay 31 ′.

  Also in this case, when the piston rod 40 ′ of the cylinder 4 ′ is extended or retracted, the C hook attachment 2 swings around the axis of the support shaft 32 ′ via the stays 30 ′ and 31 ′. (See FIG. 2, one-dot chain line).

  As shown in FIGS. 2 and 3, a bracket 5 extending in the vertical direction is disposed between the cylinders 4, 4 ′ offset in the front-rear direction.

  As shown in FIG. 4, a shaft 6 extending in the vertical direction is inserted inside the bracket 5, and the shaft 6 is inserted through the bracket 5 and extends upward and downward. The shaft 6 is rotatably supported on the bracket 5 by bearings 50 and 51 provided on the inside and the upper end of the bracket 5, respectively.

  The shaft 6 has a lower portion 60 disposed below the bracket 5 (see FIG. 5), and a hole 60a extending in the horizontal direction is formed through the lower portion 60. A support shaft 61 is inserted through the hole 60a, and the support shaft 61 is rotatably supported by the hole 60a. The upper ends of the frames 34 and 35 are connected to the end portion of the support shaft 61, and the frames 34 and 35 are swingable around the axis of the support shaft 61.

  As shown in FIG. 5, a key groove 62 a is formed at the upper end 62 of the shaft 6. In this example, the key groove 62a is formed at two positions 180 degrees apart on the circumference at the upper end 62 of the shaft 6 (see FIG. 7). A key 64 is engaged with the key groove 62a.

  These key grooves 62 a are provided for attaching the sprocket 10 (FIG. 4) to the upper end 62 of the shaft 6. As shown in FIG. 4, a drive shaft 11 is juxtaposed on the side of the shaft 6. A sprocket 12 is attached to the upper end of the drive shaft 11, and a chain 13 is wound around each sprocket 10, 12. Although not shown, a part of the sprocket 12 is connected to the tip of a piston rod of a cylinder as an actuator. By extending or retracting the piston rod of the cylinder, the sprocket 12 rotates and the chain 13 is Through which the sprocket 10 rotates. As a result, the shaft 6 rotates forward or backward, so that each C hook attachment 2 connected to the lower end of the shaft 6 via the support shaft 61 and the frames 34 and 35 pivots around the axis of the shaft 6. It has become. That is, the shaft 6 functions as a turning portion of the C hook attachment 2.

  As shown in FIG. 5, a screw portion 63 is formed below the upper end 62 of the shaft 6. The key groove 62 a extends downward to a position near the screw portion 63. A nut (for example, a hexagonal nut) 7 is screwed to the screw portion 63, and an engaging member 8 is engaged with the outer periphery of the nut 7 (see FIG. 4). A plate 9 is disposed on the engaging member 8. The plate 9 is fixed to the engaging member 8 by welding or adhesion.

  As shown in FIG. 6, the engaging member 8 is a C-shaped or U-shaped (or U-shaped) member having a notch 80, and the notch 80 is lateral to the nut 7. It is formed in a shape that can be engaged with the outer peripheral surface of the nut 7 and can be engaged with the outer peripheral surface of the nut 7 in a relatively non-rotatable manner. In this case, the notch 80 has two parallel parallel surfaces 80a and 80b at the opening, and the distance between the two surfaces 80a and 80b is larger than the distance between the parallel parallel two surfaces 70 and 71 of the nut 7. Slightly larger. The opposing two surfaces 80 a and 80 b of the notch 80 are engaged with the opposing two surfaces 70 and 71 of the nut 7. In this example, the outer periphery of the engaging member 8 is formed in a polygonal shape, but this may be circular.

  As shown in FIG. 7, the plate 9 is, for example, an annular (that is, disk-shaped) member, and a central through hole 90 through which the upper end 62 of the shaft 6 can be inserted is separated from the center 2 by 180 °. It has a key groove (key engaging portion) 9a which is formed at a location and can be engaged with the key 64. Further, the outer peripheral edge 91 of the plate 9 is larger than the outer peripheral edge 72 of the nut 7 and slightly smaller than the outer peripheral edge 81 of the engaging member 8. This is to facilitate the welding operation when the plate 9 is fixed to the nut 7 by welding. Alternatively, this is to secure a bonding margin when the plate is bonded to the nut 7.

  As described above, the nut 7 is screwed into the threaded portion 63 of the shaft 6, the engaging member 8 is engaged with the outer periphery of the nut 7, and then the plate 9 is disposed on the engaging member 8. By fixing 9 to the engaging member 8, a structure for preventing the nut 7 from loosening with respect to the shaft 6 is formed.

  As shown in FIG. 1, a guide frame 110 extending in the front-rear direction is provided above the C hook attachment 2. The guide frame 110 is supported from below by an arm 120 connected to the rear end side. The arm 120 is provided so as to be lifted and lowered by a lifting device 130 disposed behind the arm 120.

  The guide frame 110 is provided with a slide frame 100 slidable in the front-rear direction via guide rollers 101 and 102. A cylinder 140 is disposed on the guide frame 110 in the front-rear direction, and the piston rod 141 of the cylinder 140 is connected to the rear end of the slide frame 100. By driving the cylinder 140 and extending or retracting the piston rod 141, the slide frame 100 moves in the front-rear direction along the guide frame 110.

  As shown in FIG. 4, the bracket 5 and the drive shaft 11 are attached to the slide frame 100. When the slide frame 100 moves, each C hook attachment 2 moves together with these members. .

Next, the assembly procedure of the nut locking structure according to this embodiment will be described with reference to FIGS.
First, the shaft 6 is inserted into the bracket 5 and is rotatably supported by bearings 50 and 51 (see FIG. 4). Next, the nut 7 is screwed into the threaded portion 63 of the shaft 6, and the nut 7 is tightened (see FIG. 5). At this time, if the tightening of the nut 7 is weak, the shaft 6 is rattled in the vertical direction. On the other hand, if the nut 7 is tightened too much, a large thrust due to the tightening of the nut 7 causes a bearing 51 from the seat surface of the nut 7. , 50 makes it difficult for the bearings 50 and 51 to rotate. Therefore, when tightening the nut 7, the tightening amount of the nut 7 is appropriately adjusted so that the shaft 6 rotates smoothly without rattling. .

  After the tightening position of the nut 7 is determined, the engaging member 8 is engaged from the side of the nut 7 (see FIG. 5). At this time, since the nut 7 is a hexagonal nut, the engaging member 8 can be attached to any two sides of the nut 7 from three directions (see FIG. 6).

  After the engagement member 8 is attached, the plate 9 is inserted from the upper end 62 of the shaft 6 to place the plate 9 on the engagement member 8, and the key groove 62 a of the upper end 62 of the shaft 6 and the key of the plate 9 are placed. With the groove 9a aligned, the key 64 is engaged with these key grooves 62a, 9a (see FIG. 7). At this time, since the plate 9 is an annular member, the overlap region between the plate 9 and the engaging member 8 does not change even when the engaging member 8 is engaged with the nut 7 from any direction. From this state, the outer peripheral edge 91 of the plate 9 is fixed to the upper surface of the engaging member 8 by welding. In this way, the assembly of the locking structure for the nut 7 is completed.

  In this case, the engagement member 8 is fixed to the nut 7 so as not to be relatively rotatable, and the plate 9 is fixed to the nut 7 in a state where the plate 9 is fixed to the key groove 62a of the shaft 6. Loosening prevention is performed.

  Next, the sprocket 10 is inserted into the upper end 62 of the shaft 6 from above and is key-coupled to the key groove 62 a of the upper end 62. Thereafter, the end plate 14 is fixed to the upper end of the sprocket 10 to prevent the sprocket 10 from coming off from the shaft 6.

Next, the cargo handling work by the forklift 1 configured as described above will be briefly described.
At the time of cargo handling work, for example, the forklift 1 is directly opposed to the coil material, which is a cargo handling object, and the forklift 1 is moved forward toward the coil material, whereby each C hook attachment 2 is moved forward.

  When each C hook attachment 2 is moved forward, the slide frame 100 is advanced by driving the cylinder 140 (FIG. 1) and extending the piston rod 141 as necessary. Then, the bracket 5 and the shaft 6 are moved together with the slide frame 100 (refer to the two-dot chain line in FIG. 1), whereby each C hook attachment 2 is connected via the support shaft 61, the frames 34 and 35, and the support shafts 32 and 32 ′. Moves forward.

  At this time, by appropriately driving the lifting device 130 (FIG. 1), the lower extension 2B of the C hook attachment 2 is passed through the central hole of the coil material. At this time, if necessary, the cylinders 4 and 4 ′ (FIG. 2) are driven to extend or retract the piston rods 40 and 40 ′, so that the C hook attachment 2 is attached to the support shafts 32 and 32 ′. The angle of inclination of the C hook attachment 2 is adjusted by swinging it around (see the dashed line in FIG. 2).

  And the raising / lowering apparatus 130 is driven, and the lower extension part 2B of the C hook attachment 2 is moved upward, whereby the coil material is lifted upward by the lower extension part 2B. At this time, the weight of the coil material acts on the frames 30, 30 ′, 34, 34 ′ from the C hook attachment 2, and as a result, the frames 34, 34 ′ swing a little around the axis of the support shaft 61. The weight balance is adjusted.

  At this time, the sprocket 10 is rotated via the chain 13 by rotating the sprocket 12 (FIG. 4) by driving a cylinder (not shown). Then, the support shaft 61 rotates together with the shaft 6, and as a result, the C hook attachment 2 turns around the axis of the shaft 6 via the frames 34, 34 ′, 35. Thereby, the direction of the coil material suspended by the C hook attachment 2 can be changed.

<Other Example 1>
In the above-described embodiment, the sprocket is described as an example of the fixing member that is key-coupled to the upper end 62 of the shaft 6, but a gear or other member may be used instead of the sprocket.

<Other Example 2>
In the said Example, although the hexagonal nut was demonstrated as an example as the nut 7 screwed together with the thread part 63 of the axis | shaft 6, you may make it use the nut which has outer peripheral shapes other than a hexagonal nut. For example, the outer peripheral shape may be a cylindrical surface, and nuts having a pair of parallel surfaces formed at two positions 180 ° apart on the cylindrical surface may be used.

<Other Example 3>
In the above-described embodiment, an example in which the plate 9 is fixed to the shaft 6 and the plate 9 is key-coupled to the shaft 6 is shown, but the application of the present invention is not limited to this.

  Spline connection or serration connection may be employed instead of key combination. In this case, splines or serrations may be formed at positions in the immediate vicinity of the threaded portion 63 of the shaft 6, and spline holes or serration holes that engage with the splines or serrations may be formed in the plate.

  In this case, the plate fixed to the shaft 6 by spline coupling or serration coupling is fixed to the engaging member 8 engaged with the nut 7 by welding or adhesion, so that the shaft 6 is The nut 7 can be reliably prevented from loosening with respect to the screw portion 63.

  Also in this case, if the spline or serration formed on the shaft 6 is for attaching a sprocket or gear as a fixing member fixed to the upper end 62 of the shaft 6, a dedicated spline for the plate Further, it is not necessary to separately form serrations on the shaft 6, and the nut 7 can be prevented from loosening by using splines and serrations originally formed on the shaft 6, so that the manufacturing cost can be reduced and the structure can be simplified.

<Other application examples>
In the above-described embodiment, an example in which the nut locking structure according to the present invention is applied to the turning portion of the C hook attachment of the forklift is shown. However, the present invention is a rotating portion (turning portion and hinge portion) of other attachments of the forklift. Further, the present invention can be applied to a twist lock shaft portion of a spreader type large forklift used for cargo handling work of a marine container.

  The present invention can also be applied to rotating parts (turning part and hinge part) of industrial vehicles other than forklifts, and further applicable to hub nut tightening parts of front axles and rear axles.

  As described above, the nut loosening prevention method and the nut loosening prevention structure according to the present invention are suitable for a turning part of an attachment of an industrial vehicle, particularly a forklift.

1: Forklift (industrial vehicle)

2: C hook attachment (attachment)

6: Shaft 62a: Keyway 63: Screw part 64: Key

7: Nut 70, 71: Opposing surface

8: Engagement member 80: Notch

9: Plate 90: Through hole 9a: Key groove (key engaging part)

10: Sprocket (fixing member)

50, 51: Bearing

Japanese Utility Model Publication No. 7-41932 (see FIGS. 1 to 10)

Claims (20)

A method for preventing the nut from loosening,
Prepare a shaft having a threaded portion to which the nut can be screwed and a keyway disposed in the vicinity of the threaded portion, and screw the nut into the threaded portion,
An engagement member having a notch that can be engaged with the nut so as not to rotate relative to the nut is prepared, and the notch of the engagement member is engaged with the nut.
Preparing a plate having a hole through which the shaft can be inserted and a key engaging portion into which a key inserted into the key groove can be engaged, and passing the shaft through the hole in the plate; And engaging the key with the key engaging portion,
The plate is fixed to the engaging member.
A nut locking method characterized by that. In claim 1,
The key groove and the key inserted in the key groove are for attaching a fixing member fixed to the shaft so as not to rotate.
A nut locking method characterized by that. A method for preventing the nut from loosening,
Preparing a shaft having a threaded portion to which the nut can be screwed, and a spline or serration disposed in the vicinity of the threaded portion, and screwing the nut into the threaded portion;
An engagement member having a notch that can be engaged with the nut so as not to rotate relative to the nut is prepared, and the notch of the engagement member is engaged with the nut.
A plate having a hole through which the shaft can be inserted and a spline hole or serration hole into which the spline or serration can be engaged is prepared, and the shaft is passed through the hole of the plate, and the spline hole of the plate Or engage the spline or serration of the shaft with the serration hole,
The plate is fixed to the engaging member.
A nut locking method characterized by that. In claim 3,
The spline or serration is for attaching a fixing member that is non-rotatably fixed to the shaft.
A nut locking method characterized by that. In claim 2 or 4,
The fixing member is a sprocket or a gear;
A nut locking method characterized by that. In claim 1 or 3,
The notch of the engaging member is provided so as to be able to engage with an outer surface of the nut.
A nut locking method characterized by that. In claim 6,
The nut is a hex nut, and the outer surface of the hex nut that can be engaged with the notch of the engagement member is two opposing surfaces of the hex nut.
A nut locking method characterized by that. In claim 1 or 3,
The plate is welded or bonded to the engagement member;
A nut locking method characterized by that. In claim 1 or 3,
The shaft is rotatably supported by a bearing, and the nut is a member for smoothly rotating the shaft without play by pressurizing the bearing in the axial direction.
A nut locking method characterized by that. In claim 1 or 3,
The shaft constitutes a turning part of the attachment of the industrial vehicle,
A nut locking method characterized by that. A nut locking structure,
A shaft having a threaded portion and a keyway disposed in the vicinity thereof;
A nut screwed into the threaded portion of the shaft;
An engagement member having a notch that engages with the nut in a relatively non-rotatable manner;
A key engaging portion with which a key inserted into the key groove is engaged, and a plate having a hole through which the shaft is inserted;
The plate is fixed to the engaging member;
A nut locking structure characterized by that. In claim 11,
A fixing member is fixed to the shaft so as not to rotate through the key inserted into the keyway.
A nut locking structure characterized by that. A nut locking structure,
A shaft having a spline or serration disposed in the vicinity of the thread portion; and
A nut screwed into the threaded portion of the shaft;
An engagement member having a notch that engages with the nut in a relatively non-rotatable manner;
A plate having a spline hole or serration hole with which the spline or serration engages, and a hole having a hole through which the shaft is inserted,
The plate is fixed to the engaging member;
A nut locking structure characterized by that. In claim 13,
A fixing member is fixed to the shaft in a non-rotatable manner through the spline or serration.
A nut locking structure characterized by that. In claim 12 or 14,
The fixing member is a sprocket or a gear;
A nut locking structure characterized by that. In claim 11 or 13,
The notch of the engagement member is engaged with an outer surface of the nut;
A nut locking structure characterized by that. In claim 16,
The nut is a hex nut, and the notch of the engagement member is engaged with two opposing surfaces of the hex nut;
A nut locking structure characterized by that. In claim 11 or 13,
The plate is welded or bonded to the engagement member;
A nut locking structure characterized by that. In claim 11 or 13,
The shaft is rotatably supported by a bearing, and the nut is a member for smoothly rotating the shaft without play by pressurizing the bearing in the axial direction.
A nut locking structure characterized by that. In claim 11 or 13,
The shaft constitutes a turning part of the attachment of the industrial vehicle,
A nut locking structure characterized by that.

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