JPH0243664Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to an improvement of a torque wrench equipped with two toggle links.

In other words, the operator senses that a predetermined torque value has been reached and immediately reduces the tightening force, but by the time the operator reduces his manual force due to inertia, a larger torque is applied to the object to be tightened. To prevent this, after the toggle link is activated, the head further bends against the grip to absorb the inertia of the operator and eliminate overtorque to the object to be tightened. Torque wrenches have already been proposed. Further, to explain this torque wrench using the conventional example shown in FIGS. 1 to 4, a head 1' for fastening a bolt 21 is connected to a tube 2' which also serves as a grip part with a pin 3'.
A link B4' is connected to the other end by a support shaft a. Link B4' is pressed against head 1' at an angle β ₂ by spring force.

Link-A5' is connected to the other end of link-B4' at an angle _α1 by a support shaft b, and the other end of link-A5' is connected to the thruster 11 by a support shaft c. It is connected to a spring 13 via the same spring receiver 12 as in the conventional type. The spring 13 can be adjusted to change the operating torque by adjusting the compression force of the spring 13.
The other end is held down by an adjustment screw 14, and the adjustment screw 1
4 is connected to tube 2' with a screw.

In Fig. 1, when α ₂ > α ₁ , when the manual force F is applied and the predetermined torque is reached, the link A5' operates first and compresses the spring 13, and the link A5' rises to α' ₁ (the (See Figure 2).

At this time, the link B4' remains pressed against the head 1 and moves together with the head 1'. Head 1' is bent by θ due to the action of link A5'. Link-A5' is β' ₁ with respect to link-B4'
It rises to an angle of , and stops when it hits link B4'. At this time, similar to the conventional preset type torque wrench, the operator is informed that the predetermined torque has been reached by a sudden decrease in torque and the sound of link -A5' hitting link -B4'.

When the operator continues to apply manual force F due to inertia, link A5' and tongue B4' come together to form one link, and the angle becomes γ.

Link-A5' and link-B4' work together until the angle becomes γ', and then bend further until head 1' hits tube 2' (third
(see figure).

Figure 4 shows the change in torque value during this period. By applying manual force F until time K, the predetermined torque _T0 is reached.
The link A5' then operates, the torque decreases due to the toggle action, and the link A5' hits the link B4'. The operator knows from this sound and the sudden drop in torque that the predetermined torque T ₀ has been reached, but continues to apply further manual force F due to inertia.

Therefore, if link-A5' and link-B4' are combined to form one link and operate so that γ<α ₁ , this operating torque _T'0 is smaller than _T0 , so excessive torque does not occur.

If the time for this second stage operation is set to 5/100 seconds or more, the operator will normally reduce the manual force F before the second stage operation is completed, which will prevent the generation of excessive torque. .

However, in such conventional torque wrenches, the second stage torque T' ₀ is set to be smaller than the first stage torque T ₀ , and the tightening is always performed correctly with the torque not exceeding T ₀ . However, on the other hand, since the torque T′ ₀ in the second stage is low, the force that bends the torque wrench greatly due to inertia, that is, △C shown in Figure 4, acts, causing the operator to do extra work. However, the disadvantage was that the workers were highly fatigued.

The present invention was devised to eliminate such drawbacks, and in a preset type torque wrench that incorporates two toggle links and operates in two stages, the first toggle link that operates first is set at the lower limit of the screw tightening tolerance. The second toggle link, which is to be activated next, is made to work at the upper limit of the tolerance, thereby eliminating the drawbacks of the conventional example, and achieving the above-mentioned 2.
It is an object of the present invention to provide a torque wrench that is equipped with a micro switch that operates in conjunction with step operation, and is capable of lighting up to indicate when the toggle is in operation.

The present invention will be explained in detail below based on the embodiments shown in FIGS. 5 to 7. The structural diagram shown in FIG. 6 shows only the main parts of the torque wrench according to this embodiment, and the other parts are omitted because they are the same as the structure of the conventional example.

2 is a tube of a preset type torque wrench that is equipped with two toggle links (shown in the conventional example) and operates in two stages, and a thruster 11 is located within this tube 2; A switch operation pin 17 is provided protrudingly. Reference numerals 18 and 19 are two micro switches fixed to the tube 2. Normally, the pin 17 is used to press the micro switch 18.
However, when the tightening work is started and the first stage toggle link is activated, the pin 17 moves to the right in FIG. 18, the micro switch 18 is turned on. Further, by operating the torque wrench, the pin 17 is moved to the position indicated by the chain line 17' near the end of the operation of the second stage toggle link, and the micro switch 19 is moved.
This turns on the . 31 is a lower limit torque indicator light that lights up when the reset switch 37 is closed;
32 is an appropriate torque indicator, 33 is an upper limit torque indicator, 34 is a power source, and 35 and 36 are relays.

The above is the configuration of this embodiment. Next, to describe the operation, first, when starting the screw tightening work using the torque wrench, the adjustment screw 14 is rotated, and the operating torque of the second stage toggle link is The value is set to the upper limit Tmax of the screw tightening tolerance, and then the operating torque value of the first stage toggle link is adjusted to the lower limit of the screw tightening tolerance by rotating the correction screw 16.
Set to Tmin. Next, the torque wrench thus set is used to tighten the screw, but if the first stage toggle link operates at point K during this tightening operation, this first stage toggle link operation is mechanically performed at point K. perceived by the senses. Immediately after that, the torque value drops rapidly and reaches point A in FIG. It is visually confirmed that Tmin has been reached. Therefore, the feeling that the first stage toggle link has been moved at point K is confirmed by vibration and visual inspection, and the inertia of the tightening manual force disappears without operating the second stage toggle link (point S in Figure 5). reference),
The tightening torque T is within tolerance. However, when the second-stage toggle link is operated due to the large inertia of the tightening manual force, the operation of the toggle link is again sensually recognized due to vibration transmission, and furthermore, near the end of the second-stage toggle link's operation (the 5
(see point B in the figure), the micro switch 19 closes,
Since the upper limit torque indicator light 33 is lit, it is visually confirmed that the tightening torque has reached Tmax.

That is, in the normal state (when no screw tightening operation is being performed), the micro switch 18 is open, so the lower limit torque indicator light 31 is lit by the power supply 34, but due to the tightening operation, the first stage When the toggle link is operated and the micro switch 18 moves, the relay 35 operates and the proper torque indicator light 32 is activated.
lights up and is self-holding. When further tightening force is applied and the second stage toggle link operates, the micro switch 19 is activated, and if there is a risk of overtorque, the relay 36 is activated, and the upper limit torque indicator light 33 lights up to maintain self-holding. Therefore, by lighting the upper limit torque indicator light 33, the danger of overtorque (see point F in FIG. 5) can be eliminated. Once the tightening is completed, it can be released by pressing the reset button 37.

As described above, the present invention provides a preset torque wrench that incorporates two toggle links and operates in two stages, including: a first switch that is closed by the operation of the first stage toggle link that operates first;
The second circuit is closed by the operation of the second stage toggle link.
a lower limit torque indicator light that is turned off when the first switch is closed; an upper limit torque indicator light that is turned on when the second switch is closed; and a lower limit torque indicator light that is turned off when the first switch is closed; Since this torque wrench is characterized by being equipped with a proper torque indicator light that lights up when the second switch is closed and goes off when the second switch is closed, the operation of both micro switches 18 and 19 and each display are light 3
Depending on the lighting status of 1, 32, and 33, the tightening status of the screws associated with the operation of each toggle link can be displayed by lighting, so you can visually check the tightening status of the screws according to the feeling of reaching the torque due to the vibration (operation) of the toggle link. The tightened state of the screw can be effectively confirmed, and therefore the risk of overtorque can be effectively eliminated.

[Brief explanation of the drawing]

Fig. 1, Fig. 2, and Fig. 3 are cross-sectional views showing the operating state of a conventional torque wrench equipped with two toggle links; Fig. 4 is a graph showing the operation of the torque wrench; Fig. 5. 6 is a graph showing the operation of the torque wrench according to the present invention, FIG. 6 is a sectional view showing the main parts of the torque wrench according to the present invention, and FIG. 7 is a circuit diagram of the display mechanism. 2...tube, 11...thruster, 17...pin,
18, 19...Micro switch, 31, 32, 3
3... Confirmation lamp, 34... Power supply, 35, 36... Relay, 37... Reset switch.

Claims (1)

[Scope of utility model registration request] In a preset type torque wrench that has two built-in toggle links and operates in two stages, the first switch is closed by the operation of the first stage toggle link that operates first, and the first switch is closed by the operation of the second stage toggle link. a lower limit torque indicator light that is turned off when the first switch is closed; an upper limit torque indicator light that is turned on when the second switch is closed;
A torque wrench characterized in that it is equipped with a proper torque indicator light that is turned on when the first switch is closed and turned off when the second switch is closed.