JPH0242122B2 - - Google Patents

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to an improvement in screws, and it is possible to accurately control the tightening torque of bolts and nuts so as not to apply undue load to the bolts and nuts. It pertains to what has been done.

[Technical background of the invention and its problems] When tightening bolts and nuts, if the tightening torque is lower than the required torque, the bolts and nuts will become dense, and conversely, if the tightening torque is lower than the required torque, If the voltage is high, too much load is applied and the bolt
This will cause deformation and damage to the nut. Therefore, the tightening torque of bolts and nuts must be adjusted to the required torque. For the above reasons, conventional bolt tightening machines are equipped with a torque detector for the purpose of stable bolt tightening, and the torque is controlled by comparing the detected tightening torque with the required torque. was being carried out.

However, when a bolt tightening machine is equipped with a torque detector in this manner, the structure becomes complicated, the cost becomes relatively high, and the strength of the bolt tightening machine tends to be weak, which is a problem.

Further, since special tools such as bolt tightening machines are large and unsuitable for work at high places, it has been desired to be able to control the tightening torque of bolts with a regular wrench or the like.

[Object of the Invention] The present invention was proposed in order to solve the problems of the prior art as described above, and its purpose is to adjust the tightening torque of the screw itself without using a torque detector. By configuring the bolt tightening machine so that it can be controlled, the configuration of the bolt tightening machine can be simplified and the cost of bolt tightening work can be reduced.
To provide a screw that can obtain stable torque even when tightening with a normal wrench or the like during work at high places.

[Summary of the Invention] The screw of the present invention is provided by dividing the screw into two parts concentrically in the radial direction to form two members: a screw base having a threaded portion and a tightening case having a fixing portion of the tightening means;
The screw base and the tightening case are rotatably fitted together, and when tightening the screw, the screw base and the tightening case are connected and fixed with a torque key, and the strength of the torque key is set to a specified value to the outer tightening case. It is set so that it will shear when a torque greater than the torque is applied.

With this configuration, when tightening a bolt, the screw base and the tightening case are connected and fixed by the torque key, and the tightening means is fixed to the tightening case. The rotation applies a tightening force to the tightening case, thereby tightening the screw base that is integrated with the tightening case. After the screw base is tightened to the specified torque, if a torque exceeding the specified torque is applied to the tightening case, the torque key will be sheared and the screw base and the tightening case will be separated. The clamping force applied to
Only the tightening case is rotated, and a torque exceeding a predetermined torque is not applied to the screw base. In this way, according to the screw of the present invention, the tightening torque can be controlled by the configuration of the screw itself.

[Embodiment of the Invention] Next, an embodiment in which the present invention is applied to a bolt will be specifically described with reference to the drawings.

In the bolt shown in the front view of FIG. 1 and the cross-sectional view of FIG. A locking protrusion 1a is provided at one end of the inner circumferential surface. A head 2b of a cylindrical screw base 2 having a threaded portion 2a is inserted into the inner periphery of the tightening case 1 so as to be concentric with the tightening case 1.

As shown in the enlarged view of FIG. 3, the threaded portion 2a side of the head 2b of the screw base 2 is locked by the protrusion 1a of the tightening case 1, and the opposite side of the head 2b is locked by the other end 1b. They are caulked and fixed, whereby the tightening case 1 and the screw base body 2 are rotatably fitted.

Furthermore, key grooves 3a and 3b are provided at two locations on the inner peripheral surface of the tightening case 1 and the outer peripheral surface of the head 2b of the screw base body 2, respectively, dividing the circumference into two. A torque key 4 is inserted into a key groove 3 formed in a state where the two are aligned.

In addition, between the threaded part 2a and the tightening case 1,
A disk-shaped washer 5 is inserted. This washer may be a spring washer other than the one shown in the drawings, or a flange may be provided on the outer periphery of the tightening cage 1 to form a flanged bolt or a flanged nut. Also,
As shown in FIG. 3, a ring-shaped projection 6 for adjusting frictional resistance is provided on the threaded portion 2a side of the tightening case 1.

The operation of this embodiment having the above configuration is as follows.

That is, when tightening a bolt, first align the key grooves 3a and 3b of each member and insert the torque key 4 thereto, as shown in FIG. 4, to tighten the screw base 2 and the tightening case. Connect and fix 1. In this state, the tightening case 1 is fixed to a bolt tightening machine or wrench, etc., and the tightening case 1 is tightened by the rotation thereof, and the tightening case 1 and the screw base 2 are rotated together, and the screw base 2 is tightened. Attachment will be made.

Then, after the screw base 2 is tightened to a predetermined torque, the tightening force applied to the tightening case 1 becomes more than the predetermined torque, so the torque key 4 is sheared, and the screw base 2 and the tightening Case 1 is separated. As a result, as shown in FIG. 5, the tightening force applied to the tightening case 1 rotates only the tightening case 1, and a torque exceeding a predetermined torque is not applied to the screw base body 2.

Therefore, when the screw of this embodiment is used, the tightening torque can be controlled only by the configuration of the screw itself, so there is no need to provide a torque detector in the bolt tightening machine as in the conventional case. This makes it possible to simplify the bolt tightening machine and therefore reduce costs.
Additionally, since the weakness of the bolt tightening machine is eliminated, its durability can be improved. On the other hand, stable torque can be obtained even when using a normal wrench or the like when working in high places. Furthermore, as a result of the tightening case 1 being separated from the screw base 2, the screw cannot be loosened without inserting the torque key 4 again, so there is no possibility of loosening even when an external force is applied, which is good for crime prevention. Are better.

Furthermore, in this embodiment, since the ring-shaped protrusion 6 for adjusting frictional resistance is provided on the threaded portion 2a side of the tightening case 1, the frictional resistance can be easily calculated, and the frictional resistance can be easily calculated based on the calculated frictional resistance. Torque key 4
The intensity can be set. Further, the strength of the torque key 4 can be freely adjusted by appropriately selecting the material, thickness, number, etc. of the torque key, and examples of the material of the torque key include steel, aluminum, plastic, etc. Furthermore, the number of key grooves is also appropriately selected depending on the number of torque keys 4. Note that the work will be easier if the washer 6 is attached in advance.

Further, the planar shape of the fixing portion of the tightening means of the tightening case 1 is not limited to the hexagonal shape as shown in the above embodiment, but also the oval shape as shown in FIG. 6, and the planar shape as shown in FIG. A rectangular shape may also be considered.

Furthermore, the embodiment shown in FIGS. 8 to 10 is an application of the present invention to a nut, and its structure is completely the same as the bolt of the previous embodiment except for the difference in the shape of the bolt and nut. , Therefore, since the effects are the same, the same parts are given the same symbols,
The explanation will be omitted.

Such a nut may be used in combination with the bolt of the previous embodiment, or the present invention may be applied only to either the bolt or the nut. Furthermore, the present invention is applicable not only to bolts and nuts, but also to wood screws, countersunk screws, etc., and in these cases, as shown in FIG. Since the fixing part 11 of the attaching means is located at the center of the screw head, the tightening case 1 is on the inside and the head 2b of the screw base 2 is on the outside.

In each of the above embodiments, when loosening a screw, a new torque key 4 that can withstand at least a larger shearing force than when tightening is inserted into the keyway 3, and the screw is tightened again with the screw base 2. After connecting the case 1 with the case 1, by applying a certain torque to the tightening case 1, the screw portion 2a of the screw base body 2 integrated with the case 1 can be loosened. However, if the torque key 4 that has been sheared during tightening remains in the keyway 3, the following problem will occur.

In other words, when loosening a screw, use a new torque key 4.
Since the screw cannot be inserted, the screw base body 2 and the tightening case 1 cannot be connected, and therefore the screw cannot be loosened.

The solution in this case is to increase the number of keyways 3 for the torque key 4 in advance, and use separate keyways 3 for tightening and loosening, so that at least a larger shearing force than when tightening is applied. It is conceivable to insert a durable loosening torque key 4.

[Effects of the Invention] As explained above, according to the present invention, a torque detector can be used with a simple structure in which a screw is divided into a screw base and a tightening case, and both are connected by a torque key set to a predetermined strength. Since the tightening torque can be controlled using the screw itself without the need to use a We can provide excellent screws that can obtain high torque.

In particular, the present invention is excellent in crime prevention since once the screw has been tightened, it cannot be loosened unless a release key is prepared. Additionally, since the end of the keyway is exposed, there is an advantage that the screw can be reused by replacing the key.

[Brief explanation of the drawing]

1 to 5 are views showing an embodiment in which the present invention is applied to a bolt, respectively. FIG. 1 is a front view from the head side, FIG. 2 is a partial sectional view, and FIG. 3 is a Figure 2 is an enlarged view of part A, Figure 4 is a perspective view showing when tightening is started, Figure 5 is a perspective view showing when tightening is completed, Figures 6 and 7 are bolts shown in Figure 1. FIGS. 8 to 1 are perspective views showing different embodiments in which the head of the
0 shows an embodiment in which the present invention is applied to a nut, FIG. 8 is a front view, FIG. 9 is a partial sectional view, and FIG.
FIG. 10 is an enlarged view of part B in FIG. 9, and FIG. 11 is a sectional view showing an embodiment in which the present invention is applied to a countersunk screw. DESCRIPTION OF SYMBOLS 1...Tightening case, 1a...Protrusion, 1b...Caulking end, 2...Screw base, 2a...Threaded part, 2
b... Head, 3, 3a, 3b... Keyway, 4...
Torque key, 5... washer, 6... ring-shaped protrusion,
11...Fixed part.

Claims (1)

[Claims] 1 Divide the screw into two concentrically in the radial direction,
A screw base having a threaded portion and a tightening case having a fixing portion of the tightening means are two members, and the screw base and the tightening case are rotatably fitted, and the screw base and the tightening case are in contact with each other. Opposing key grooves extending in the axial direction of the screw are formed on the surfaces, and one end of the key grooves formed in the screw base and the tightening case is exposed on the end surface of the screw, and a certain amount of tightening is carried out in the key groove. A screw characterized by inserting a key that is sheared with applied torque.