JP2024013571A - Nut cap and nut fastener - Google Patents

Abstract

PROBLEM TO BE SOLVED: To surely prevent a nut from being loosed and falling in a situation that an impact, vibration or the like is intermittently continued.

SOLUTION: A nut cap 20 is fit to an external periphery of each of a plurality of nuts 6 for screwing a rotating body 3 into a bolt 2 protruding from a rotating hub 1, and attaching it to the rotating hub 1. Engagement grooves 10 formed at side peripheral faces of the nuts 6 extend along nut rotation directions. When fastened, a binding band 11 is stuck and fastened in a loop shape from the outside in the radial direction into the engagement grooves 10 of the nuts 6 which are aligned at equal intervals along a circumferential direction with respect to a rotation center of the rotating body 3. In the nut cap 20, opening parts 22 for allowing the passage of the binding band 11 which is stuck to the engagement grooves 10 of the nuts 6 are formed at least at two points.

SELECTED DRAWING: Figure 4

COPYRIGHT: (C)2024,JPO&INPIT

Description

The present invention relates to a nut cap and a nut locking device.

Patent Document 1 describes a plurality of mounting parts that are press-fitted one by one into the outer circumferential side of the wheel nut, and a system that connects these mounting parts to each other in order to prevent the wheel nut from loosening due to shocks, vibrations, etc. during driving. A rotation stopper is disclosed in which a plurality of mounting parts and a connecting part are integrally molded from a soft material such as resin.

According to the rotation stopper of Patent Document 1, even if there is an angular phase difference between the wheel nuts to be connected, the flexibility of the connecting part absorbs the phase difference and the mounting part can be press-fitted into the wheel nut. It is said that it can be done.

Utility Model Publication No. 6-43330

However, the fact that the connecting part made of soft material is flexible means that the binding force of the connecting part on the attached part is weak, allowing the attached part to rotate or displace. Therefore, there was a problem in that it was difficult to reliably prevent the wheel nuts from loosening and eventually falling off.

This kind of problem is not unique to wheel nuts, but also in general rotating bodies (e.g. pulleys, rollers, etc.) that are fixed to a rotating hub with multiple sets of bolts and nuts, and shocks and vibrations continue intermittently. It can happen under the circumstances.

The present invention has been made in view of the above-mentioned current situation, and a technical object thereof is to provide a structure that prevents a nut under fastening from loosening and falling off.

The invention includes a nut cap and a nut locking device, and exemplary constructions are specified in the claims. Among these, the invention according to claim 1 is a nut cap that is fitted on the outer periphery of each of a plurality of nuts for mounting a rotating body on the rotating hub by screwing into bolts protruding from the rotating hub, the nut cap being fitted on the outer periphery of each of the nuts The engagement grooves formed on the surfaces extend along the nut rotation direction, and when fastened, the engagement grooves of each nut are arranged at equal intervals along the circumferential direction with respect to the rotation center of the rotating body. A cable tie is fitted into the engagement groove from the outside in the radial direction and tightened in a loop shape, and at least two openings are formed through which the cable tie fitted in the engagement groove of each nut passes. There is.

According to a second aspect of the invention, in the nut cap according to the first aspect, a cutout groove is formed on the side facing the rotating body.

The invention according to claim 3 relates to a nut loosening stopper, which includes a plurality of nuts that are screwed onto bolts protruding from a rotating hub to attach a rotating body to the rotating hub, and the side circumferential surface of the nuts includes a plurality of nuts that are screwed into bolts protruding from a rotating hub, and which have a plurality of nuts on the side circumferential surface thereof in the direction of rotation of the nuts. a nut having an engaging groove extending along the nut, and a radially outer groove formed in the engaging groove of each nut arranged at equal intervals along the circumferential direction with respect to the rotation center of the rotating body when fastened. The present invention includes a binding band that is fitted into the loop and tightened into a loop, and a nut cap according to claim 1 or 2.

According to the present invention, during fastening, there are three steps: engagement of the binding band with the engagement groove of each nut, fitting of the nut cap to each nut, and insertion of the binding band into the opening of the nut cap. Together, these structures can easily and accurately prevent each nut from loosening (dislodging). Therefore, it is possible to prevent each nut from loosening and falling off, and as a result, it is possible to exhibit a high effect of preventing the rotating body from falling off.

FIG. 2 is an exploded perspective view of a wheel and an axle hub. It is explanatory drawing of the wheel nut of embodiment, (a) is a front view, (b) is a top view, (c) is a bottom view, and (d) is a right view. It is an explanatory view of a wheel nut according to another example in which the formation position of the engagement groove is changed, in which (a) is a front view, (b) is a top view, (c) is a bottom view, and (d) is a right side view. be. It is an external perspective view of a nut cap. It is an explanatory view of a nut cap, (a) is a top view, (b) is a front view, (c) is a bottom view, (d) is a left view, (e) is a right view, and (f) is a rear view. In the figure, (g) is a cross-sectional view taken along line gg in (a), and (h) is a cross-sectional view taken along line h-h in (a). (a) is an explanatory view showing a state in which the nut loosening stopper is attached, and (b) is a partially enlarged view. (a) is an enlarged sectional view when a nut loosening stopper is applied to a single tire wheel, (b) is an enlarged sectional view with the nut cap broken, and (c) is a partial enlarged sectional view of (b). . (a) is an enlarged sectional view when a nut loosening device is applied to a wheel for double tires, (b) is an enlarged sectional view with the nut cap broken, and (c) is a partial enlarged sectional view of (b). .

Next, embodiments of the present invention will be described in detail with reference to the drawings. In the embodiment of the present invention, a case is illustrated in which a wheel 3 is attached to an axle hub 1 in a vehicle such as a truck or a bus. A vehicle typically has at least four wheels 3. The wheel 3 corresponds to a rotating body, and the axle hub 1 corresponds to a rotating hub.

As shown in FIG. 1, a plurality of wheel bolts 2 protruding outward in the axial direction are arranged concentrically and at equal intervals with respect to the axial center of the axle hub 1 on a flange portion of an axle hub 1 provided on a vehicle. installed. In the wheel 3, bolt insertion holes 4 corresponding to the respective wheel bolts 2 are formed concentrically with respect to the center of rotation and arranged at equal intervals.

Lay the wheel 3 on the axle hub 1, insert each wheel bolt 2 of the axle hub 1 into the corresponding bolt insertion hole 4, and tighten the wheel nut 6 onto the wheel bolt 2 with a predetermined torque using, for example, a torque wrench. The wheel 2 is attached to the axle hub 1 by screwing.

As the mounting structure of the wheel 3 to the axle hub 1, there are two types: a flat seat method in accordance with the ISO (International Standard) standard, and a spherical seat method in accordance with the JIS (Japanese Standard) standard. The embodiments shown in FIGS. 2 to 8 are of the flat seat type according to the ISO standard, and exemplify the case where the wheel 3 is attached to the axle hub 1 with eight sets of wheel bolts 2 and wheel nuts 6.

Note that, in both the ISO standard flat seat system and the JIS standard spherical seat system, the wheel 3 may be attached to the axle hub 1 using ten sets of wheel bolts 2 and wheel nuts 6. Further, an embodiment in which the present invention is applied to a plane seat system according to the ISO standard will be described below, but it goes without saying that the present invention can be similarly applied to a spherical seat system according to the JIS standard.

The nut loosening stopper 5 of the embodiment shown in FIGS. 2 to 8 includes a plurality of wheel nuts 6 that are screwed into wheel bolts 2 protruding from an axle hub 1 to attach a wheel 3 to the axle hub 1, and a plurality of wheel nuts 6. It is equipped with a binding band 11 that can be wrapped around. A nut cap 20 is placed over the outer periphery of each wheel nut 6 (also referred to as the nut body 7).

The wheel nut 6 of the embodiment is of a flat seat type based on the ISO standard, and includes a nut body 7 having a polygonal shape (in this case, a hexagonal shape) in plan view and having a screw hole 9, and a nut body 7 on the seat surface side of the nut body 7. It has a circular flange-shaped flat seat 8 attached thereto. The wheel nut 6 of the embodiment is made of metal such as steel, stainless steel, chromium alloy, or aluminum alloy.

An engagement groove 10 extending along the nut rotation direction (circumferential direction) is formed on the side circumferential surface of the wheel nut 6, that is, on the side circumferential surface of the nut body 7. As shown in FIGS. 2 and 3, the engagement groove 10 in the nut body 7 may be formed closer to the top surface or closer to the flat seat 8. The shape of the engagement groove 10 may be, for example, an L-shaped notch, but it is more preferable if it is a concave groove with walls on both sides in the height direction.

In the embodiment, an engagement groove 10 is formed over the entire circumferential side surface of the wheel nut 6 (nut body 7). The engagement groove 10 may be formed by cutting out at least the side circumferential corner portion 7a of the wheel nut 6 (the nut body 7), and may have a form in which there is no groove near the center of the side circumferential surface (the wheel nut 6 ( A form in which an engagement groove 10 extends intermittently on the side peripheral surface of the nut body 7).

The binding band 11 of the embodiment is made of metal such as steel, stainless steel, chromium alloy, or aluminum alloy, and includes a band-shaped band portion 12 and a cylindrical buckle portion attached to one longitudinal end of the band portion 12. It is equipped with 13. The basic structure of the binding band 11 is similar to the existing one, although the length of the band portion 12 is long, for example, about 1 m.

A locking protrusion (not shown) is provided within the buckle portion 13. The locking projection contacts the wide side of the band portion 12 inserted into the buckle portion 13, and allows the other end of the band portion 12 in the longitudinal direction to be inserted through the buckle portion 13 to form a loop. , is configured to prevent the other end of the band portion 12 in the longitudinal direction from being pulled out from the buckle portion 13 as it is.

Note that a band presser 14 may be attached to the band portion 12 to pull and hold the other end in the longitudinal direction so as to overlap the one end in the longitudinal direction. Note that the structure of the binding band 11 in the embodiment is merely an example, and it is of course possible to employ a binding band 11 having a different structure. The material of the binding band 11 is not limited to metal, but may be made of synthetic resin as long as strength and the like can be ensured.

For example, the wheel nut 6 is screwed onto the wheel bolt 2 with a predetermined torque using a torque wrench or the like, and the wheel 3 is attached to the axle hub 1 (this state may be referred to as "fastened" in this specification). In the state in which the binding band 11 is wound around the wheel nuts 6 groups in a loop shape, the groove depth of the portion of each engagement groove 10 corresponding to the side circumferential corner portion 7a of the wheel nut 6 (nut body 7) is The dimension Dg is set larger than the thickness dimension Tb when the band portion 12 is viewed from the bolt axis direction under fastening (Dg>Tb).

With this configuration, even if the wheel nut 6 tries to loosen due to impact or vibration, for example, the band portion 12 of the binding band 11 will be caught in the engagement groove 10, so that the wheel nut 6 will be loosened in the bolt axis direction (the longitudinal direction of the wheel bolt 2). direction) cannot be moved (not loosened). That is, the engagement relationship between the engagement groove 10 and the band portion 12 prevents each wheel nut 6 from loosening (dislodging). Therefore, it is possible to prevent each wheel nut 6 from loosening and falling off the wheel bolt 2, and as a result, it is possible to exhibit a high effect of preventing the wheel 3 from falling off.

The nut cap 20 of the embodiment is made of a synthetic resin such as polyurethane resin, vinyl chloride resin, polyethylene terephthalate, polycarbonate, acrylic resin, nylon resin, polyethylene resin, or fluorinated ethylene resin, and includes the wheel nut 6 (the nut body 7 ) is formed into a ring shape that surrounds the entire side circumferential surface. The nut cap 20 may be made of metal. The shape of the nut cap 20 is not limited to a ring shape, but may be a lid shape with one end open.

The inner peripheral surface of the nut cap 20 is formed with an uneven portion 21 consisting of a repetition of a concave portion 21a and a convex portion 21b continuous in the circumferential direction. As shown in FIGS. 4 and 5(a) and 5(c), the inner circumferential surface of the nut cap 20 of the embodiment has a twenty-square star shape in plan view due to the presence of the uneven portions 21. When the nut cap 20 is placed on the outer periphery of the nut body 7, each side circumferential corner portion 7a of the nut body 7 fits into the corresponding recess 21a of the nut cap 20, and the wheel nut 6 and the nut cap 20 are moved relative to each other. It is held non-rotatable.

Note that the inner circumferential surface of the nut cap 20 is not limited to a twenty-square star shape in plan view, but may be twelve-sided, eighteen-sided, or thirty-sided. The inner peripheral surface of the nut cap 20 may have a star shape that is a multiple of the polygonal shape of the nut body 7. The nut cap 20 may be press-fitted onto the outer periphery of the wheel nut 6.

As shown in FIGS. 7 and 8, the width Wc of the nut cap 20 (see FIGS. 5(b), (d), (e), and (f)) is the groove width of the engagement groove 10 formed in the nut body 7. It is set larger than the dimension Wg (Wc>Wg). Therefore, by covering the outer periphery of the nut body 7 with the nut cap 20, it is possible to cover the engagement groove 10 of the nut body 7 with the nut cap 20.

The nut cap 20 is formed with at least two groove-shaped or hole-shaped openings 22 through which the band portion 12 of the binding band 11 fitted into the engagement groove 10 of the nut body 7 passes. Each opening 22 in the embodiment is formed by cutting out a long groove on the side of the nut cap 20 that faces the flat seat 8 of the wheel nut 6 (the side that faces the wheel 3). The nut cap 20 of the embodiment has three openings 22 cut out at equal intervals along the circumferential direction.

The inner circumferential surface of the nut cap 20 of the embodiment has a twenty-square star shape in plan view due to the presence of the uneven portions 21. Moreover, the nut cap 20 has three openings 22 cut out at equal intervals along the circumferential direction. Therefore, when the binding band 11 is wound around the wheel nuts 6 in a loop shape, the band portion 12 of the binding band is attached to each wheel nut 6 regardless of the phase state of each wheel nut 6 in the nut rotation direction. can pass through adjacent openings 22, 22 of the nut cap 20 fitted over the nut cap 20. That is, after wrapping the binding band 11 around the group of wheel nuts 6, the nut cap 20 can be easily placed on the outer periphery of each wheel nut 6.

Note that the opening 22 is not limited to a cutout groove shape as in the embodiment, but may be an elongated hole shape. It is sufficient that the openings 22 are formed in at least two locations in the nut cap 20 (four or more locations are also acceptable). The size of the aperture phase θ (see FIG. 4(b)) of the apertures 22 is not particularly limited because it depends on the number of apertures 22. In the case of the embodiment, it is more preferable to set the aperture phase θ of the aperture 22 to a range of, for example, about 30° to 90°.

The width dimension Wo of each opening 22 (see FIGS. 5(b), (d), (e) and (f)) is set to be smaller than the width dimension Wb of the band part 12 in order to make it easier to insert the band part 12 of the binding band 11. is also set large (Wo>Wb).

As shown in FIGS. 4 to 8, the inner circumferential surface of the nut cap 20 has a front edge corresponding to the side circumferential corner portion 7a of the engagement groove 10 of the wheel nut 6 (nut body 7) into which the nut cap 20 is fitted. An inwardly convex locking rib 23 that can be caught and engaged with the portion 10a is formed. In the embodiment, an inwardly convex locking rib 23 is integrally formed in the middle part in the width direction of a recess 21a formed in a portion of the inner peripheral surface of the nut cap 20 where the opening 22 is not provided. The width dimension Wl of the locking rib 23 is set smaller than the groove width dimension Wg of the engagement groove 10 (Wl<Wg) in order to make it easy to fit into the engagement groove 10.

When the nut cap 20 is placed on the outer periphery of the nut body 7 and each side circumferential corner portion 7a of the nut body 7 is fitted into the corresponding recess 21a of the nut cap 20, the locking part located halfway in the width direction of the recess 21a is engaged. The rib 23 is forcibly engaged (depressed and caught) with the front edge portion 10a of the engagement groove 10 corresponding to the side circumferential corner portion 7a. As a result, the nut cap 20 is irremovably attached to the nut body 7 (see FIGS. 6(b), 7(b), and 8(b)).

For example, when the wheel nut 6 is screwed into the wheel bolt 2 with a predetermined torque using a torque wrench or the like, and the wheel 3 is attached to the axle hub 1, each wheel nut 6 is attached to each wheel bolt 2 of the axle hub 1 and the wheel 3. As is clear from the relationship with each bolt insertion hole 4, they are arranged at equal intervals along the circumferential direction with respect to the rotation center of the wheel 3. Under such fastening, the binding band 11 is tightened (wrapped) into a loop so that the band portion 12 of the binding band 11 fits into the engagement groove 10 of each wheel nut 6 from the outside in the radial direction of the wheel 3. (See FIG. 6(a)).

Then, the phase of the nut cap 20 is adjusted so that the band portion 12 passes through the adjacent openings 22, 22 of the nut cap 20, and the nut cap 20 is fitted onto the outer periphery of the nut body 7 of the corresponding wheel nut 6. Then, each side circumferential corner portion 7a of the nut body 7 is fitted into the corresponding recess 21a of the nut cap 20. Then, the locking rib 23 located halfway in the width direction of the recess 21a sinks into the front edge portion 10a of the engagement groove 10 corresponding to the side circumferential corner portion 7a, and the nut cap 20 is held against the nut body 7. (See FIG. 6(b), FIG. 7(b), and FIG. 8(b)).

In addition, when the openings 22 are hole-shaped, after attaching the nut cap 20 to the wheel nut 6, the binding band 11 is inserted into each opening 22 and the binding band 11 is wound in a loop shape.

According to the above configuration, even if each wheel nut 6 tries to loosen due to shock or vibration while driving, the band portion 12 of the binding band 11 is caught in the engagement groove 10, so that each wheel nut 6 has a corresponding one. The wheel bolt 2 is held in such a way that it cannot be removed.

That is, the engagement relationship between the engagement groove 10 of each wheel nut 6 and the band portion 12 of the binding band 11 prevents each wheel nut 6 from loosening (dislodging). Therefore, each wheel nut 6 can be prevented from loosening and falling off from the wheel bolt 2.

Furthermore, each wheel nut 6 is covered with a nut cap 20, and the portion where the band portion 12 is wrapped around the wheel nut 6 is covered with the nut cap 20, so that the band portion 12 is reliably prevented from falling off from the engagement groove 10. It can be prevented.

Moreover, if the wheel nut 6 tries to loosen due to shock or vibration while driving, the wheel nut 6 and the nut cap 20 cannot rotate relative to each other, so they try to rotate together, but in this case, the nut cap 20 Since one of the openings 22 always abuts against the band portion 12 of the binding band 11, loosening of the nut cap 20 and thus the wheel nut 6 is prevented.

In other words, the three structures of engagement between the engagement groove 10 and the binding band 11, fitting of the nut cap 20 into the wheel nut 6, and insertion of the binding band 11 into the opening 22 of the nut cap 20 work together. Loosening (dislodgement) of the wheel nut 6 can be easily and accurately prevented. Therefore, if the embodiment is adopted, a high effect of preventing the wheel 3 from falling off can be exhibited.

In the embodiment, the opening 22 is cut out on the side of the nut cap 20 that faces the flat seat 8 of the wheel nut 6 (the side that faces the wheel 3), so that the nut cap 20 is notched for the group of wheel nuts 6. After winding the band 11 into a loop, each wheel nut 6 can be fitted with a nut cap 20. Therefore, the workability of attaching and detaching the nut loosening stopper 5 including the nut cap 20 can be greatly improved.

In the embodiment, the combination of the wheel nut 6 and the nut cap 20 holds the band portion 12 of the cable tie 11 locally (at multiple locations), so even if the cable tie 11 breaks or is damaged, it will not be damaged. The binding band 11 can be held by the plurality of sets of the wheel nut 6 and the nut cap 20 without being released, and the binding band 11 can be reliably prevented from falling off due to breakage or the like.

In addition, a locking rib 23 protruding inward on the inner circumferential surface of the nut cap 20 is forced into a front edge portion 10a of the engagement groove 10 of the wheel nut 6 (nut body 7) corresponding to the side circumferential corner portion 7a. Since the nut cap 20 is engaged, there is very little risk of the nut cap 20 falling off the wheel nut 6.

It is desirable that the binding band 11 is tightened by pulling the other longitudinal end of the band portion 12 in the direction in which the wheel nut 6 loosens. In the case of the embodiment (ISO standard), the tightening direction of the wheel nut 6 is right-handed for both the left and right wheels 3 of the vehicle, so as shown in FIG. It is best to tighten the other longitudinal end by pulling it counterclockwise.

Then, when the brake is applied, a load is applied to the other end of the band portion 12 in the longitudinal direction in the direction of insertion into the buckle portion 13. That is, since a load is applied in a direction that tightens the binding band 11 more, it is possible to suppress the binding band 11 from falling off.

On the other hand, when the JIS standard spherical seat system is adopted, the tightening direction of the wheel nut 6 is left-handed for the left wheel 3 of the vehicle, and right-handed for the right wheel 3. Therefore, for the left wheel 3, the other end of the band portion 12 in the longitudinal direction is tightened clockwise, and for the right wheel 3, the band portion 12 is tightened as shown in FIG. 6(a). It is best to tighten the other longitudinal end of the tube by pulling it counterclockwise.

Then, when applying the brake, a load is applied to the other longitudinal end of the band portion 12 in the direction of insertion into the buckle portion 13 in either the left or right wheel 3 . That is, since a load is applied in a direction that tightens the binding band 11 more, it is possible to suppress the binding band 11 from falling off.

As shown in FIGS. 7(a)(b) and 8(a)(b), the nut loosening device 5 of the embodiment can be used for a single tire wheel 3, or a double tire wheel 3. It can also be adopted for wheels 3, 3 for use. In the flat seat system of the ISO standard, in the case of wheels 3, 3 for double tires, the length of each wheel bolt 2 becomes long.

Note that at least one of the three surfaces constituting the engagement groove 10 may be subjected to a surface roughening process such as buffing or blasting, or the inner surface of the band portion 12 in a looped state and the end surfaces on both sides of the inner surface may be roughened. If at least one surface of the wheel nuts 6 is subjected to surface roughening treatment, the frictional force increases when the engagement groove 10 of each wheel nut 6 and the band portion 12 of the binding band 11 are engaged, so that It is more effective in preventing loosening. Of course, both the engagement groove 10 and the band portion 12 may be surface roughened, or only one of them may be roughened.

Moreover, instead of the surface roughening treatment described above, the band holder 14 is made of synthetic resin such as a silicone tube, and covers approximately the entire length of the band part 12 (the band part 12 is inserted into the band holder 14). may be configured. In this case, the buckle portion 13 and the other end of the band portion 12 in the longitudinal direction protrude from each end of the band presser 14 in the longitudinal direction and are exposed.

With this configuration, the engagement between the engagement groove 10 of each wheel nut 6 and the band retainer 14 increases the frictional force, and it is possible to effectively prevent each wheel nut 6 from loosening. When tightening the binding band, since the band portion 12 is inserted into the band presser 14, there is little frictional resistance and the band can be tightened smoothly.

Note that the configuration of each part in the present invention is not limited to the illustrated embodiment, and can be variously modified without departing from the spirit of the present invention.

In the embodiment of the present invention, the case where the wheel 3 is attached to the axle hub 1 in a vehicle such as a truck or a bus is exemplified, but the present invention is not limited to this. It is also possible to apply the present invention to all rotating bodies (for example, pulleys, rollers, etc.) that are fixed to a rotating hub with nuts.

1 Axle hub (rotating hub)
2 Wheel bolt 3 Wheel (rotating body)
5 Nut loosening stopper 6 Wheel nut 7 Nut body 7a Side peripheral corner 10 Engagement groove 10a Front edge portion 11 Binding band 12 Band portion 20 Nut cap 21 Uneven portion 21a Recess 21b Convex portion 22 Opening 23 Locking rib

Claims (3)

A nut cap that is fitted onto the outer periphery of each of a plurality of nuts that are screwed into bolts protruding from the rotating hub to attach a rotating body to the rotating hub,
The engagement grooves formed on the side peripheral surface of each nut extend along the nut rotation direction, and when fastened, are arranged at equal intervals along the circumferential direction with respect to the rotation center of the rotating body. A cable tie is fitted into the engagement groove of each nut from the outside in the radial direction and tightened into a loop shape,
at least two openings are formed through which the binding band fitted in the engagement groove of each nut passes;
nut cap. A cutout groove is formed on the side facing the rotating body.
The nut cap according to claim 1. A plurality of nuts that are screwed onto bolts protruding from the rotating hub to attach the rotating body to the rotating hub, the nuts having engagement grooves extending along the rotational direction of the nuts formed on their side circumferential surfaces;
A binding band that is fitted from the outside in the radial direction into the engagement grooves of the nuts that are arranged at equal intervals along the circumferential direction with respect to the rotation center of the rotary body when fastened, and is tightened into a loop shape;
The nut cap according to claim 1 or 2 is provided.
Nut loosening device.

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