A ratchet wrench that can tighten even loose nuts.

Abstract

This ratchet wrench allows tightening or loosening of nuts with only one hand, even when the nuts are loose, and improves work efficiency by ensuring stable engagement between the ratchet and the nut. [Solution] In a ratchet wrench 1 in which the ratchet part 4 engages with a nut 9, a load-applying member 6 is provided on the ratchet part 4 that contacts a bolt 8, thereby applying frictional force or resistance to the bolt 8. This frictional force or resistance is set to be greater than or equal to the minimum resistance value required for the ratchet mechanism to rotate in one direction. A spring and its protective material, or an elastic member can be used as the load-applying member.

Description

Technical Field

[0004]

[0001] The present invention relates to a ratchet wrench used for tightening or loosening bolts and nuts in assembly and disassembly operations of various mechanical devices and in construction assembly operations.

Background Art

[0002] Generally, a ratchet wrench engages a ratchet portion with a nut and rotates the nut by reciprocally rotating a handle. FIGS. 15 and 16 are diagrams illustrating a conventionally generally known ratchet wrench. In this ratchet wrench 50, a ratchet portion 54 disposed on a wrench body 2 having a handle 3 engages and integrates with the wrench body 2 in either the right or left rotational direction with respect to the wrench body 2 by a built-in ratchet mechanism not shown, and when a relative torque of a predetermined value or more acts in the rotational direction opposite to the integrating rotational direction, it is configured to fit so as to freewheel.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Patent Document 3

[0005] Conventionally, when tightening, before attaching the ratchet part 54 to the nut 59, Then tighten the nut 59, and when loosening it, use a ratchet to some extent. After loosening it with a wrench, the ratchet part 54 is released from its attachment to the nut 59, and the nut 59 is tightened by hand. The restrictions are being eased. However, if there are scratches or rust in the middle of the bolt, it becomes impossible to tighten or loosen the nut by hand. A ratchet wrench must be used first, and after the nut has passed the scratches or rust, it must be rotated again by hand. In other words, there is a problem in that continuous ratchet wrench work is not possible. Furthermore, with spring washers that exert a large reaction force, hand-tightening may not adequately compress the spring washer, and as mentioned above, the ratchet mechanism may not function properly.

[0006] The present invention aims to provide a ratchet wrench that allows the tightening or loosening of a nut to continue even when the nut has become loose due to the proper functioning of the ratchet mechanism.

[0007] In prior literature, there is no solution to restore the function of the ratchet mechanism by providing a fulcrum on the bolt, which is the basic principle of the present invention. However, if we were to mention one, Patent Document 1 proposes a solution in which a thumb handle is provided on the upper part of the ratchet mechanism, and the user grasps the handle with one hand and rotates the thumb handle on the upper part of the ratchet with the other hand. However, in terms of work efficiency, it is not expected to make a significant difference compared to directly tightening or loosening the nut by hand. Also, because the thumb handle is provided on the upper part of the ratchet, its use is limited to nuts that penetrate the bolt. (Patent Document 1)

[0008] Patent Document 2 proposes a means of rotating the second drive mechanism that rotates the ratchet part around its longitudinal axis, independently of the reciprocating rotation of the handle. This invention, like the one described above, has a mechanism at the top of the ratchet to switch the direction of rotation, thus limiting its use to nuts that pass through bolts. (Patent Document 2)

[0009] Patent Document 3 proposes a method for driving a second drive mechanism that rotates the ratchet part with a reciprocating motion in the longitudinal axis direction, separate from the reciprocating rotation of the handle. This second drive mechanism also employs a ratchet mechanism and has a switching mechanism. Therefore, there are two operating parts for switching the rotation direction of the ratchet part, and it is necessary to match the rotation direction, making the operation complicated. Furthermore, the reciprocating motion of the second drive mechanism is effective only when tightening or loosening the nut, as it is driven in only one direction, and the rotation of the ratchet part is effective, but it is not possible to rotate the nut in both directions, resulting in poor work efficiency. In addition, the structure is complex and high cost. (Patent Document 3)

[0010] Patent Document 4 proposes a structure in which a gear is provided in the ratchet part, a second drive mechanism is connected via a belt or chain, and multiple ratchet mechanisms are combined to provide auxiliary drive. However, this structure is complex and does not directly solve the problem of "not being able to ensure rotation of the ratchet part in one direction" that occurs when the nut is loose. (Patent Document 4) [Means for solving the problem]

[0011] The ratchet wrench of the present invention comprises a wrench body and a ratchet portion that is rotatably supported on the wrench body via a ratchet mechanism. The ratchet portion engages with a nut screwed onto a bolt to perform work, and the ratchet portion is provided with a load-applying member that contacts the bolt to apply frictional or resistive force.

[0012] The frictional or resistive force applied to the bolt by the load-applying member shall be greater than or equal to the minimum resistance value necessary for the ratchet mechanism to ensure unidirectional rotation of the nut. Furthermore, it should be small enough not to hinder the process of rotating the nut in the intended direction. This setting allows the ratchet mechanism to rotate the nut in the desired direction even when the nut is loosely screwed in, thus maintaining normal ratchet operation.

[0013] The load-applying member can be a spring that contacts the bolt, a bolt protective material or friction member placed on the spring, or an elastic member that contacts the bolt, or a combination of these.

[0014] Furthermore, the ratchet mechanism can be switched using either a left / right switching lever or a method that does not have a switching lever and switches the direction of rotation by reversing the wrench body. [Effects of the Invention]

[0015] According to the present invention, since the load-applying member applies a predetermined resistance to the bolt, the problem of not being able to ensure rotation in one direction of the ratchet mechanism even when the nut is extremely loosely screwed in is prevented, and continuous tightening and loosening operations become possible.

[0016] Furthermore, since the load-applying member contacts the bolt, a lead (distance traveled in the axial direction) is generated by the rotation of the ratchet. This lead is equivalent to that of the nut, and the engagement depth between the nut and the ratchet remains unchanged, improving work efficiency. In addition, while methods using magnets in the ratchet are generally employed to stabilize engagement with the nut, the effect of the present invention is that it does not depend on whether the nut is made of a magnetic or non-magnetic material.

[0017] The structure is simple and does not require a complex mechanism like the conventional examples (Patent Documents 1, 2, 3, 4), so the operability can be improved without increasing the manufacturing cost.

Brief Description of the Drawings

[0018] [Figure 1] It is a plan view schematically showing a first embodiment of a ratchet wrench according to the present invention. [Figure 2] It is a side view schematically showing the first embodiment as a partial cross section. [Figure 3] It is a plan view schematically showing a second embodiment. [Figure 4] It is a side view schematically showing the second embodiment (when tightening) as a partial cross section. [Figure 5] It is a side view schematically showing the second embodiment (when loosening) as a partial cross section. [Figure 6] It is a plan view schematically showing a third embodiment. [Figure 7] It is a side view schematically showing the third embodiment as a partial cross section. [Figure 8] It is a perspective view schematically showing a ratchet gear portion of the third embodiment as a partial cross section. [Figure 9] It is a perspective view schematically showing a ratchet gear portion of the third embodiment. [Figure 10] It is a plan view schematically showing a fourth embodiment. [Figure 11] It is a side view schematically showing the fourth embodiment (when tightening) as a partial cross section. [Figure 12] It is a side view schematically showing the fourth embodiment (when loosening) as a partial cross section. [Figure 13] It is a perspective view schematically showing a ratchet gear portion of the fourth embodiment as a partial cross section. [Figure 14] It is a perspective view schematically showing a ratchet gear portion of the fourth embodiment. [Figure 15] It is a plan view explaining the usage state of the conventional example. [Figure 16]This is a cross-sectional view of the usage description of a conventional example. [Modes for carrying out the invention]

[0019] Preferred embodiments of the present invention will be described with reference to the accompanying drawings. Note that the embodiments described below do not limit the scope of the present invention as defined in the claims. Furthermore, not all of the configurations described below are essential requirements of the present invention.

[0020] In Figures 1 and 2, which show a first embodiment of the present invention, the ratchet wrench 1 has a handle 3 connected to a wrench body 2 which incorporates a ratchet mechanism (not shown), and a ratchet part 4 is fitted and supported on the wrench body 2, and a rotation switching lever 5 for the ratchet mechanism is attached thereto.

[0021] When the switching lever 5 is switched to the R side, the ratchet part 4 engages with the handle 3 and becomes integrated with it when it rotates clockwise, and when it rotates counterclockwise, it rotates freely relative to the wrench body 2 due to a relative torque of a predetermined value or more. Conversely, when the switching lever 5 is switched to the L side, it engages with the handle 3 and becomes integrated with it when it rotates counterclockwise, and when it rotates clockwise, it rotates freely relative to the wrench body 2 due to a relative torque of a predetermined value or more. Note that the bolts and nuts in this embodiment are described as having standard threads (right-hand threads).

[0022] Here, a spring 6 is attached to the upper surface of the ratchet part 4 by fixing screws 6a, 6b, and 6c. Furthermore, a bolt protection material 7 is wrapped around the spring 6. When the ratchet part is assembled to the bolt, that is, when the bolt protection material grips the bolt, it is necessary to provide the resistance required for the ratchet gear to rotate. This torque must be greater than the free-spinning start torque of the ratchet mechanism. Furthermore, it should be small enough not to hinder the process of rotating the nut in the intended direction. It is necessary that the ratchet mechanism functions correctly even when assembled to the bolt without a nut.

[0023] Figures 3 to 5 show the main parts of a ratchet wrench 20 according to a second embodiment of the present invention. In Figures 3 to 5 and Figures 6 to 16 described later, components with the same reference numerals as those in Figures 1 to 2 are substantially the same as those with the same reference numerals in Figures 1 to 3, so their explanation is omitted. Unlike the first embodiment of the present invention, this ratchet wrench 20 does not have a rotation switching member for the ratchet mechanism, and the engagement rotation direction is fixed to either the right or the left. The engagement rotation direction is changed by flipping the upper and lower surfaces of the ratchet wrench body. Therefore, it is necessary to enable engagement of the nut with the ratchet part from both sides. For this reason, the spring and bolt protector must be installed in the middle of the ratchet part. The torque required for the bolt protector to rotate against the bolt is the same as in the first embodiment. Figure 4 is a schematic side view showing a partial cross-section when the nut 9 is being tightened. Figure 5 is a schematic side view showing a partial cross-section when loosening nut 9. The ratchet wrench 20 of this second embodiment can be expected to have the same effects and advantages as the ratchet wrench 1 of the first embodiment.

[0024] Figures 6 to 9 show the main parts of a ratchet wrench 30 according to a third embodiment of the present invention. In this ratchet wrench 30, rubber is used instead of a spring to resist the bolt. It also has a rotation switching function for the ratchet mechanism. As shown in Figure 8, the nut is assembled to the ratchet in only one direction, so the rubber needs to be installed on the opposite side from the direction of nut insertion. The torque required for the rubber to rotate relative to the bolt is the same as in the first embodiment. Figure 7 is a schematic side view showing a partial cross-section. Figures 8 and 9 are detailed diagrams of the ratchet gear. The ratchet wrench 30 of this third embodiment can be expected to have the same effects as the ratchet wrench 1 of the first embodiment.

[0025] Figures 10 to 14 show the main parts of a ratchet wrench 40 according to a fourth embodiment of the present invention. In this ratchet wrench 40, rubber is used to resist the bolt. Furthermore, there is no rotation switching mechanism for the ratchet mechanism, and the engagement rotation direction is fixed to either the right or the left, and the engagement rotation direction is changed by flipping the top and bottom surfaces of the ratchet wrench body. Accordingly, as shown in Figure 13, it is necessary to be able to engage the nut with the ratchet part from both sides. For this reason, the rubber must be installed in the middle of the ratchet part. The torque required for the rubber to rotate against the bolt is the same as in the first embodiment. Figure 11 is a schematic side view showing a partial cross-section when a nut is being tightened. Figure 12 is a schematic side view showing a partial cross-section when loosening a nut. Figures 13 and 14 are detailed diagrams of the ratchet gear. The ratchet wrench 40 of this fourth embodiment can be expected to have the same effects as the ratchet wrench 1 of the first embodiment. [Explanation of symbols]

[0026] 1. Ratchet wrench 2. Wrench body 3 handles 4 ratchet gears 5. Selector lever 6. Spring 6a Spring clasp a 6b Spring clasp b 6c Spring retainer c 7 Bolt protection 8 bolts 9 nuts 10 E-rings 20 Ratchet wrench (second embodiment) 24 Ratchet gear (second embodiment) 26 Spring (Second Embodiment) 27 Bolt Protection (Second Embodiment) 30 Ratchet wrench (third embodiment) 34 Ratchet gear (third embodiment) 36 Rubber (Third embodiment) 36a Rubber through hole (Third embodiment) 36b Rubber slit (Third example) 40 Ratchet wrench (4th embodiment) 44 Ratchet gear (4th embodiment) 46 Rubber (Fourth embodiment) 46a Rubber through hole (Fourth embodiment) 46b Rubber slit (Fourth example) 50 Ratchet wrench (conventional example) 54 Ratchet gear (conventional example) 58 Bolt (conventional example) 59 Nut (conventional example) 60 Spring washer (conventional example) 61 Washer (conventional example) 62 Plate (conventional example) 63 Device body (conventional example) Imaginary lines indicating direction 100

Claims

1. A ratchet wrench characterized by comprising: a wrench body; a ratchet part rotatably supported on the wrench body via a ratchet mechanism, which engages with a nut screwed onto a bolt and rotates the nut in a certain direction; and a load-applying member which contacts the bolt when the bolt is assembled to the ratchet part, and converts the frictional force or resistance force generated between the bolt and the ratchet part into torque to suppress the rotation of the nut or the ratchet part relative to the bolt when the wrench body is rotated in the opposite direction to the certain direction.

2. The ratchet wrench according to claim 1, wherein the load-applying member is a spring, or a protective member or friction member disposed on the spring, or a combination thereof.

3. The ratchet wrench according to claim 1, wherein the load-applying member is an elastic member, or a protective member or friction member, or a combination thereof, is disposed on the elastic member.

4. The ratchet wrench according to claim 1, wherein the load-applying member uses a friction member.

5. The ratchet wrench according to any one of claims 1 to 4, characterized in that the ratchet mechanism has a function to switch the direction of rotation left or right by a switching lever, or the direction of rotation is switched by inverting the wrench body upside down without having a switching lever.

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