HU196503B - Torque-indicating wrench in particular for drawing screws with adjustable torque - Google Patents

Abstract

SUMMARY OF THE INVENTION The present invention relates to a torque wrench, in particular to tighten screws to an adjustable torque, which is formed by a tubular handle (3) formed to receive torque wrench handle (J1), and a handle handle (3) opposite to handle (11). at the end, a keyhead (1) suitable for gripping the screw head and a protrusion that is integral with the keyhead (1) and extends into the handle bar (3), rotatably arranged around the pin (2) in the handle bar (3). The essence of the invention is that at least a portion of the protrusion extending beyond the pin (2) of the keyhead (1) into the handle bar (3) is provided as a deflection bar (5) suitable for deflection to the handle bar (3), which is an abutment pin (5). the end of the handle (11) is fixed to the inside of the handle bar (3) without displacement and rotation, while the gauge (5) is capable of changing electrical resistance to one of the elongation at the tensioning of the key (6). is arranged. 196503 -1-

Description

FIELD OF THE INVENTION The present invention relates to a torque wrench for tightening screws with adjustable torque, the handle of the torque wrench being integrally formed with a tubular handle head for receiving torque measuring means, and an end for locking the handle shaft with a key for the handle. a projection extending into the handle shaft and arranged in the handle shaft for rotation about a pin.

As is known, in practice, torque gauge clips operating exclusively on a mechanical basis are widespread. They can be used within tight torque limits due to the mechanical principle of operation, e.g. 20-60 Nm, 40'-80 Nm 60-160 Nm ... 280-600 Nm. For each of the known tools, the required torque limit is adjusted by varying the spring force (usually a disk spring). Within the torque range, each occurring torque limit must be set with separately supplied accessories (socket wrenches, etc.), which increases the assembly technology lead times, sometimes requiring several times the main operating time.

Due to the high value of the spring, it undergoes a significant permanent deformation during use, which may cause the torque value set on the tool to be significantly different from that realized in practice. The accuracy of the tool is further diminished by the wear of the movable elements during use.

For these reasons, torque wrenches often need to be checked for accuracy (replacement, recalibration). The current torque gauge clips use a click sound when the set torque limit is reached, and its perception depends on external noise and subjective factors. Also, the tool arm cannot be extended for easier effort, as this changes the set torque value.

Such torque wrenches are the home-made Cro-Dym and foreign Beta, Saltus, etc. blade.

It is an object of the present invention to overcome these shortcomings and to provide a torque-gauge keychain whereby the value of the force exerted can be continuously monitored, the size limit extended, economical manufacturing and component typing are ensured.

The invention is based on the discovery that the bending of a key made of a suitable material is proportional to the torque during the tightening of the screw, and thus the torque value can be converted into an electrical signal that can be displayed by means of a measuring tape known per se.

It is an object of the invention that at least a portion of the key head projection extending non-contact beyond the pin is designed as a gauge block for deflection relative to the handle stem, the end of the gauge handle being disposed at one end of the handle, A strain gauge suitable for a change in electrical resistance proportional to the elongation at which the elongation is applied is provided on its elongate side with the key.

The invention will be described in more detail with reference to the embodiment shown in the figure, which is a schematic diagram of the axial section of a torque wrench according to an embodiment of the invention.

The key head 1 shown in the figure is pivotally mounted on a tubular handle 3 via a pin 2 relative to the pin 2 axis. In this way, the axis of the key head 1, which is in alignment with the axis line of the handle 3 at rest, can be inclined at an angle during operation by leaning against the axis of the handle 3. The projection of the key head 1 is fastened to the measuring block 5 by a rivet 4 such that the rivet 4 does not prevent the bending of the measuring block 5 inside the handle shaft 3. On one side of the gauge block 5, preferably on the side of the gauge block 5 which is convexly elongated when the key is tightened, a strain gauge 6 and a compensation gauge 7 for proportional electrical resistance change of the elongation torque are provided.

The other end of the gauge block 5 is secured by a rivet 9 secured to the inner tube surface of the handle 3. Electric and electronic components are located in the cavity of the handle 3 and beyond the ring 8. The variation in the resistance of the strain gauge 6 can be measured in a known manner by means of a bridge circuit, which is also powered by a stabilized current source located in the cavity of the handle 3 beyond the ring. The output of the circuit arrangement is also connected in a manner known per se to a display 10 which may be a digital display, e.g. Digital display recalibrated to Nra or LED, etc.

The end opposite the end of the handle stem 3 towards the key head 1 ends in the handle 11. If a light emitting diode is used as a display 10, a torque wrench is provided to indicate that the maximum torque limit has been reached. In this case, the handle 11 has at its end a cone 12 which is connected to a knob 13 of a rotary potentiometer arranged on a face surface at the end of the handle 11.

The torque wrench according to the invention can be operated as follows:

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When tightened with the key head 1, one side of the measuring block 5 fixed with a rivet 9 and pivoting about the rivet 4 is elongated or stretched in a negative sense, i.e. it shrinks. The strain gauge stamp 6 placed on this side changes its resistance in proportion to the strain. The resistance difference can be measured by the bridge connection. The change in resistance due to elongation must be distinguished from the change in resistance due to temperature differences. In order to keep the latter within the permissible limits, a compensation stamp 7 is placed near the strain gauge stamp 6. Since the change in resistance as a result of elongation is both linear and linear, the increase in torque can, by calibrating the resistance change to a torque, provide essentially the value of the torque occurring. 20

The torque wrench according to the invention is of great importance in the mechanical engineering, assembly, repair, installation of machinery, equipment and vehicles, in all places where tightening with the specified torque can be important. The torque wrench according to the invention prevents the threads from being interrupted and the screws from breaking.

The invention is not limited to the solutions described in the embodiments 30, but encompasses all the solutions protected by the claims, in particular the main claim.

Claims (3)

PATENT CLAIMS A torque wrench, in particular for adjusting screws with adjustable torque, the torque wrench handle being integrally formed with a CBO-shaped handle for receiving torque-measuring means, and a screw head for receiving a key-head at the opposite end of the handle, a protrusion extending into the handle shaft adapted to pivot about the pin, characterized in that at least a portion of the protrusion of the key head (1) extending beyond the bolt (2) in contact with the handle shaft (3) ), the end of the measuring block (5) facing the handle (11) is fixed to the inside of the handle stem (3) without movement and rotation, while the measuring block (5) is broken with one of the keys a strain gauge (6) suitable for changing the electrical resistance proportional to the elongation-causing torque is provided on the elongated side of the female. Torque gauge according to Claim 1, characterized in that the switching arrangement in the handle stem (3) measures and changes the resistance of the strain gauge stamp (6) in the part between the gauge block (5) and the handle (11). , a display, and a power supply for operating the switching arrangement are provided. Torque gauge according to claim 1 or 2, characterized in that on the side of the gauge block (5) containing the strain gauge stamp (6) there is a compensating stamp (7) suitable for compensating the change in resistance due to temperature differences.