Torque wrench

Abstract

To provide a torque wrench of a small size having a torque limiter function, allowing adjustment of a torque value by operation from outside of a casing, and usable for replacing a chip of a cutting tool.SOLUTION: A torque wrench 1 houses a torque value setting mechanism 7 having a shaft part 3 inserted in a box-shaped handle of a small thickness and including a torque value setting spring 4 inside the handle. The torque value setting mechanism 7 includes a rotary body 5 which engages with external teeth 34 formed on an outer periphery of the shaft part 3, and a rocking lever 6 which is energized by the spring 4 to push the rotary body 5 against the external teeth 34. The spring 4 is arranged inside the handle in a direction substantially parallel to the shaft part 3 in a longer direction, and the spring 4 is provided with a spring pressure adjusting member 41 which is externally operable.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to a torque wrench that has a torque limiter function that prevents the tightening torque applied to the shaft from exceeding a set value, and that is capable of adjusting the set value of the tightening torque. [Background technology]

[0002] When turning or milling a workpiece such as metal, a cutting tool with a replaceable cutting tip attached to a holder may be used. When attaching such a tip to the holder, if the tightening torque of the screw is too large, the tip may be distorted or the screw may be damaged. Conversely, if the tightening torque is too small, the screw may loosen and the tip may not be fixed properly. Therefore, in order to accurately attach the tip to the holder, it is important to tighten the screw with the appropriate tightening torque.

[0003] Conventionally, there is known a torque wrench that activates a torque limiter function when the tightening torque reaches the upper limit of the set value in order to tighten a screw within a set torque range. Patent Document 1 describes a torque wrench equipped with a torque limiter that utilizes a cam mechanism, in which the spring force of a torque value setting spring acts on a roller member that engages with a cam portion via a roller holding lever body. In this invention, by making the distance between the support shaft and the point of application of the spring force transmission rod longer than the distance between the support shaft in the roller holding lever body and the roller member, it is possible to reduce the spring force relative to the reaction force generated in the roller member, and the spring and other members are made smaller and lighter.

[0004] However, this torque wrench is generally long and rod-shaped, and the torque limiter mechanism is arranged in a straight line. A torque wrench of this size and shape is not suitable for attaching and detaching a tip of a cutting tool in a narrow space.

[0005] Also, Patent Document 2 describes a torque wrench that has a size and shape suitable for attaching and detaching a cutting tool tip and is capable of applying a torque not higher than a predetermined level to a fastening member. This torque wrench is equipped with a gear arranged coaxially with a rod and a torque limiter mechanism using two leaf springs that engage with this gear, and it is possible to set an upper limit of the torque value by increasing or decreasing the offset of the leaf spring from the central axis of the rod. However, in order to change the set torque value in this torque wrench, it is necessary to disassemble the handle (housing 31), replace the leaf spring holding member (spring holders 49 and 51), and reassemble it. Therefore, it is practically difficult to change the torque value once it has been set at any time, and multiple torque wrenches with different set torque values ​​must be prepared and used separately. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Republished Patent No. 2010 / 119599 [Patent Document 2] JP 2015-199194 A Summary of the Invention [Problem to be solved by the invention]

[0007] The problem that the present invention aims to solve is to provide a small-sized torque wrench that solves the above-mentioned problems of the conventional art, has a torque limiter function, and allows the torque value to be adjusted by operation from outside the housing, and can be used to replace tips of cutting tools. [Means for solving the problem]

[0008] In order to solve the above problem, we designed a thin box-shaped handle. The fastening member has an engaging portion formed at its tip.A torque wrench having a shaft portion passing through it and a torque value setting mechanism equipped with a spring for setting a torque value housed inside the handle, the torque value setting mechanism comprising a rotating body that engages with external teeth formed on the outer periphery of the shaft portion, and a rocking lever that is biased by the spring to press the rotating body against the external teeth, the spring being arranged inside the handle with its longitudinal direction oriented approximately parallel to the shaft portion, and the spring being provided with a spring pressure adjustment member that can be operated externally.

[0009] It is also preferable that the shaft portion is disposed at one end of the handle, and the spring is disposed at the other end.

[0010] It is also preferable that the oscillating lever be a long plate when viewed from the front, have a pressing portion at one end in the longitudinal direction that abuts against the rotating body, and have a support shaft that supports the oscillating lever positioned at a position closer to the pressing portion than the center of the oscillating lever.

[0011] It is also preferable that the spring be configured to press the rocking lever via a pin having a portion that comes into contact with the rocking lever formed into a convex spherical shape. Effect of the Invention

[0012] The present invention makes it possible to provide a small-sized torque wrench that is equipped with a torque limiter function and allows the set torque value to be adjusted by operation from outside the housing, and that can be used for replacing tips on cutting tools. [Brief description of the drawings]

[0013] [Figure 1] FIG. 2 is a front view of the torque wrench according to the embodiment. [Diagram 2] FIG. 2 is a perspective view showing the torque wrench of the embodiment with the cover removed. [Diagram 3] FIG. 2 is a partial cross-sectional view showing the torque wrench of the embodiment with the cover removed. [Figure 4]10 is a diagram showing the operation of a torque value setting mechanism according to an embodiment, in which the torque value setting mechanism is indicated by a dotted line. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] The following describes an embodiment of the invention. The up, down, left and right directions in this specification correspond to the up, down, left and right directions shown in FIG. 1. As shown in FIGS. 1 to 3, the torque wrench 1 of this embodiment includes a thin box-shaped handle 2 and a shaft portion 3 having an engagement portion 32 that can engage with a fastening member such as a screw, and the shaft portion 3 penetrates the handle 2. The handle 2 of this embodiment includes a handle body 21 and a cover 22 that can cover the handle body 21, and the handle body 21 has a space that can accommodate a torque value setting mechanism 7 having a spring 4 for setting a torque value. The shaft portion 3 of this embodiment includes a shaft 31 having an engagement portion 32 formed at its tip, and a shaft holding member 33 that is arranged coaxially with the shaft 31 and holds the shaft 31. The shaft 31 and the shaft holding member 33 are not rotatable relative to each other. A plurality of spline-shaped, vertically elongated external teeth 34 are provided on the outer periphery of the shaft portion 3. The external teeth 34 of this embodiment are formed on the outer periphery of the shaft holding member 33 and are housed inside the handle 2.

[0015] As shown in FIG. 3, the torque value setting mechanism 7 in the torque wrench 1 of this embodiment includes a spring 4, a rotor 5 that engages with the external teeth 34, and a swing lever 6 that is biased by the spring 4 to press the rotor 5 against the external teeth 34. The spring 4 is disposed inside the handle 2 with its longitudinal direction oriented substantially parallel to the shaft 3, and the swing lever 6 is disposed with its longitudinal direction oriented to bridge the upper side of the spring 4 and the shaft 3. These torque value setting mechanisms 7 are housed inside the handle 2. A spring pressure adjusting member 41 is provided at the lower end of the spring 4. The spring pressure adjusting member 41 of this embodiment is a screw that can be inserted into an adjustment screw hole 23 formed in the handle body 21 from the outside of the handle 2 and screwed into the adjustment screw hole 23 to adjust the biasing force of the spring 4. Since the operation portion of the spring pressure adjusting member 41 is located outside the handle 2, the set torque value can be easily adjusted from the outside of the torque wrench 1.

[0016] Here, the torque value setting mechanism 7 of the present invention and the handle 2 in which the torque value setting mechanism 7 is housed will be described in detail. As shown in Figures 2 and 3, the handle body 21 of the embodiment has a shaft support groove 211 that supports the shaft 3, and the shaft support groove 211 is provided with an external teeth accommodating portion 212 that accommodates the portion in which the external teeth 34 are formed. In this embodiment, the shaft support groove 211 is formed at a position on the left side when viewed from the front of the handle body 21, and the external teeth accommodating portion 212 is formed at a position above the center of the shaft support groove 211.

[0017] A rocking lever accommodating portion 214 that axially supports the rocking lever 6 is provided on the upper side of the handle body 21 as viewed from the front, with the longitudinal direction oriented approximately perpendicular to the external teeth portion accommodating portion 212. The external teeth portion accommodating portion 212 and the rocking lever accommodating portion 214 are communicated with each other by a passage-shaped rotor support groove 213 that supports the rotor 5.

[0018] The rotor support groove 213 in the embodiment is formed with a vertical width approximately equal to the diameter of the rotor 5, and regulates the vertical movement of the rotor 5 fitted in the rotor support groove 213. The right end of the rotor 5 protrudes outward from the right end of the rotor support groove 21 and receives pressure from the swing lever 6 biased by the spring 4. Note that the rotor 5 in the embodiment is a steel ball, but it may be a rotor of another shape, such as a cylindrical shape.

[0019] The rocking lever 6 of the embodiment is a generally long plate-like member as seen from the front, and is provided with a protruding portion 61 that is pentagonal as seen from the front and protrudes downward to the left at the lower left corner as seen from the front. The rocking lever 6 is supported so as to be rockable about a support shaft 62 provided on the protruding portion 61. The rocking lever 6 of the embodiment is made of metal, but may be formed of other materials such as resin. The rocking lever 6 of the embodiment is provided with a pressing portion 63 that receives and presses the rotating body 5, located above the protruding portion 61 on the left side surface thereof.

[0020] A spring accommodating section 216 having a spring support hole 215 therein and accommodating a spring 4 for setting a torque value is provided on the right side of the handle body 21 when viewed from the front and below the rocking lever accommodating section 214. The longitudinal direction of the spring accommodating section 216 is approximately perpendicular to the rocking lever accommodating section 214. Therefore, the spring 4 accommodated in the spring accommodating section 216 is disposed below the rocking lever 6 with the longitudinal direction oriented approximately parallel to the shaft portion 3 and approximately perpendicular to the rocking lever 6.

[0021] The spring 4 in this embodiment has a spring pressure adjusting member 41 at its lower end and a pin 42 at its upper end, and the spring pressure is transmitted to the rocking lever 6 via the pin 42. The tip of the pin 42 in this embodiment is formed into a convex spherical shape. A part of this convex spherical surface abuts against a receiving portion 64 on the underside of the rocking lever 6 to the right of the center when viewed from the front.

[0022] Additionally, a cover fixing screw hole 25 into which a cover fixing screw 24 for attaching the cover 22 to the handle body 21 is screwed is formed between the spring accommodating portion 216 and the shaft support groove 211. When the cover 22 is attached to the handle body 21 in which the torque value setting mechanism 7 is housed, the upper edge of the cover 22 restricts the upward movement of the swing lever 6.

[0023] In this way, in the torque wrench 1 of the present invention, the torque value setting mechanism 7 is arranged so that it is approximately L-shaped when viewed from the front, and further, the torque value setting mechanism 7 and the shaft portion 3 are arranged so that they are approximately U-shaped when viewed from the front, so that the torque value setting mechanism 7 can be stored inside the handle 2 which is rectangular when viewed from the front.

[0024] Next, the operation of the torque value setting mechanism 7 of the present invention will be described. When the spring pressure adjusting member 41 is tightened, the spring 4 is compressed by being pushed from below, and the spring 4 pushes up the lower right part of the rocking lever 6 when viewed from the front. The rocking lever 6 is pushed from the lower right by the spring 4, so that the rocking lever 6 tilts slightly toward the lower left. The force that tilts the rocking lever 6 acts so that the pressing part 63 presses the rotating body 5 against the external teeth 34. The rotating body 5, which is pushed from the right side by the rocking lever 6, moves slightly to the left and is pressed against the external teeth 34, restricting the rotation of the shaft part 3. The torque wrench 1 in this state is used to tighten the fastening member.

[0025] The operator engages the engaging portion 32 with the fastening member, and grips the handle 2 to rotate the torque wrench 1. When the tightening torque reaches the set torque value, the force applied from the external teeth 34 to the rotor 5 increases, and the rotor 5 moves against the pressing force from the pressing portion 63 and overcomes the external teeth 34. In this way, the torque limiter function works, allowing the operator to sense that the tightening torque has reached the torque value.

[0026] In this embodiment, the support shaft 62 supporting the rocking lever 6 is disposed at a position closer to the pressing portion 63 than the center of the rocking lever 6. Specifically, as shown in FIG. 4, when the point where the pressing portion 63 and the rotating body 5 contact is the contact point P1 and the point where the receiving portion 64 and the pin 42 contact is the contact point P2, the distance d1 between the center point C of the support shaft 62 and the contact point P1 is shorter than the distance d2 between the center point C and the contact point P2. In this embodiment, the ratio of the lengths of the distances d1 and d2 is about 1:4. With the center point C as the fulcrum, the contact point P1 is the point of action of the lever, and the contact point P2 is the point of force of the lever, so that even with a small spring pressure, a large pressure can be applied to the rotating body 5, and the spring 4 can be made smaller in size.

[0027] Furthermore, since the distance d1 is shorter than the distance d2 in the torque value setting mechanism 7, it is possible to precisely set a fine torque value by rotating the spring pressure adjustment member 41. When the spring pressure adjustment member 41 is turned in the tightening direction, the force with which the pressing portion 63 presses the rotor 5 increases, and the rotor 5 moves in a direction approaching the shaft portion 3. This increases the upper limit of the tightening torque of the torque wrench 1. On the other hand, when the spring pressure adjustment member 41 is turned in the loosening direction, the force with which the pressing portion 63 presses the rotor 5 decreases, and the rotor 5 moves in a direction away from the shaft portion 3. This decreases the upper limit of the tightening torque of the torque wrench 1.

[0028] At this time, the upper limit of the tightening torque that is set is changed by rotating the spring pressure adjusting member 41, but the distance that the rotating body 5 moves relative to this amount of rotation is extremely small compared to the amount of rotation of the spring pressure adjusting member 41. Therefore, by rotating the spring pressure adjusting member 41, the force with which the pressing part 63 presses the rotating body 5 can be minutely changed, making it possible to finely adjust the upper limit of the tightening torque of the torque wrench 1.

[0029] Although the present invention has been described above by taking the embodiment as an example, the present invention is not limited to the above embodiment and can be embodied in various forms. For example, in the shaft portion 3 of the embodiment, the shaft 31 is detachable from the shaft holding member 33, but they may be formed integrally. If the shaft 31 is detachable as in the embodiment, the shaft 31 can be easily replaced depending on the fastened member.

[0030] In addition, in the embodiment, the shaft portion 3 penetrates one end of the handle 2, but the shaft portion 3 may be disposed in the center of the handle 2. In addition, a configuration may be adopted in which the external teeth 34 are disposed in a position on the lower side of the handle main body 21, the torque value setting mechanism 7 is disposed in an orientation that is upside down compared to the embodiment, and the spring pressure adjustment member 41 is provided on the upper side of the handle 2. [Explanation of symbols]

[0031] 1 torque wrench 2 Handle 21 Handle body 211 Shaft support groove 212 External teeth receiving part 213 Rotating body support groove 214 Swing lever housing 215 Spring support hole 216 Spring housing 22 Cover 23 Adjustment screw hole 24 Cover fixing screw 25 Screw holes for fixing the cover 3 Shaft section 31 Axis 32 Engagement part 33 Shaft retaining member 34 Outer teeth 4 Spring 41 Spring pressure adjustment member 42 pin 5 Rotating Body 6 Swing Lever 61 Protrusion 62 Spindle 63 Pressing part 64 Receiving part 7 Torque value setting mechanism

Claims

1. A shaft portion having an engagement portion at its tip that can be engaged with a fastening member is inserted into a thin box-shaped handle, A torque wrench having a torque value setting mechanism including a spring for setting a torque value housed inside the handle, The torque value setting mechanism includes: A rotor that engages with external teeth formed on an outer periphery of the shaft portion; a swing lever biased by the spring to press the rotor against the external teeth, The spring is disposed inside the handle with a longitudinal direction oriented substantially parallel to the shaft portion, The spring is provided with a spring pressure adjusting member that can be operated externally.

2. 2. The torque wrench of claim 1, wherein the shaft portion is disposed at one end of the handle and the spring is disposed at the other end.

3. 3. The torque wrench according to claim 1, wherein the rocking lever is a long plate-like member when viewed from the front, and is provided with a pressing portion at one end in the longitudinal direction that abuts against the rotating body, and a support shaft that supports the rocking lever is disposed at a position closer to the pressing portion than the center of the rocking lever.

4. 4. The torque wrench according to claim 1, wherein the spring presses the rocking lever via a pin having a portion that comes into contact with the rocking lever and is formed into a convex spherical shape.

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