JPH0413093Y2 - - Google Patents

Description

[Detailed description of the invention] [Field of application of the invention] The present invention is capable of controlling the tightening state using a torque wrench.
This invention relates to a wireless digital torque meter that can be controlled at a location away from the tightening work site.

[Background of the idea]

For example, a conventional measurement method that allows the tightening state of a torque wrench to be managed in a control room located away from the tightening work site is based on the mechanical distortion caused by the load torque of the torque wrench. A wired type that detects the amount with a strain gauge etc. and connects it to a display in the control room using this detection signal cord (cable).
In addition, the voltage signal detected by a strain gauge, etc. is amplified by an amplifier, and a V/F converter is used to convert the voltage to frequency, and the signal is sent to the control room as an FM signal.
In the control room, a method has been considered in which the receiver amplifies and detects the signal after receiving it, and then converts the detected frequency signal into a torque value and displays it. Since they are connected by wire, workability is poor, the range of movement (range of action) is narrow, and the distance between the measuring device and the display device is also limited. In addition, in the latter case, the detection and transmission circuits are complicated, expensive, and consume a large amount of power.In addition, the external size of the measuring device becomes large, which also requires maintenance and maintenance.
There were problems such as poor workability.

[Purpose of invention]

The present invention was made in order to solve the problems of the conventional technology mentioned above.The torque meter, which is a measuring device, is equipped with only an oscillating section that integrates torque detection and transmission into an integrated circuit. It is a lightweight, low power consumption, and low cost measuring device, and it can receive and display the transmitted frequency signal by counting it for a certain period of time, converting it into a torque value by calculating it with a certain function, and displaying it. It is an object of the present invention to provide a wireless digital torque meter that can perform various functions wirelessly.

[Embodiments of the invention] The invention will be described in detail below based on embodiments shown in the drawings.

Reference numeral 1 denotes a torque wrench used in this embodiment, and inside a grip tube 2 of this torque wrench 1,
A spanner body 3 supported by two points P ₁ and P ₂ is installed inside the spanner body 3, and a variable capacitance capacitor 6 composed of two opposing electrodes 4 and 5 is provided in the spanner body 3. Therefore, if elastic deformation occurs in the spanner body 3 due to tightening stress, the capacitance of the capacitor 6 is changed by the amount of this deformation. Further, a circuit case 7 is attached to the torque wrench 1, and a frequency signal oscillator A for torque measurement shown in FIG. 3 is built into the case 7. This frequency signal oscillator A is composed of a power switch 8, the variable capacitor 6, an oscillation circuit 9 using a crystal resonator, a pass/fail determination switch 10, a three-way communication circuit 11, and a transmitting antenna 12. B shown in FIG. 4 is a frequency signal receiver corresponding to the oscillator A, and this receiver B
is installed at an appropriate location, such as a control room, and its internal circuit includes a receiving antenna 13,
Antenna tuner 14, first local oscillator 15, first
It is composed of a frequency converter 16, a bandpass filter 17, a second local oscillator 18, a second frequency converter 19, a waveform shaping circuit 20, a counter circuit 21, a microcomputer 22, and a display 23.

The above is the structure of this embodiment.Next, its operation will be described.When the grip tube 2 is held and tightened, when the tightening force by the torque wrench 1 reaches a certain torque value, the spanner Distortion (elastic deformation) occurs in the main body 2, and as a result, the distance between the opposing electrode plates 4 and 5 changes, and the capacitance of the capacitor 6 changes. This change in capacitance causes the oscillation frequency of the oscillation circuit 9 to change. The frequency oscillated by this oscillation circuit 9 is tripled by a tripler circuit 11 and then transmitted from an antenna 12 as an oscillation signal. That is, the oscillation frequency, which is varied by applying torque, is transmitted as is as a signal. The signal received by the receiving antenna 13 is selected by the antenna tuner 14, converted by the frequency converter 16 according to the frequency oscillated by the first local oscillator 15, and then converted by the bandpass filter 17 into the target range. The frequency signal, which extracts only the frequency and converts it to the final target frequency by the second local oscillator 18, is sent to the waveform shaping circuit 20.
After being shaped into a rectangular wave, the signal is input to the counter circuit 21. This counter circuit 21 is controlled at fixed time intervals by a microcomputer 22, stops counting after a fixed period of time, and the microcomputer 22 inputs the count value.
Also, the frequency F0 at no load (torque = 0) is stored in the microcomputer 22 in advance, and the frequency F0 when torque is applied and changes is calculated from the frequency _F0 .
By calculating ΔF obtained by subtracting F0, the measured torque value is converted into a value and displayed on the display 23.

Therefore, according to this embodiment, since it is cordless for signal transmission using radio waves, work efficiency and
The operation and handling range have been significantly improved, and since it can be configured without the need for an amplifier section, V/F converter, detection, demodulation circuit, etc., power consumption is low, and the circuit is simple, making it compact, lightweight, The present invention has the effect of providing a torque meter that can be inexpensive, highly practical, and easy and simple to maintain.

[Summary of the idea]

As described above, the present invention changes the oscillation frequency by replacing the amount of mechanical displacement caused by applying torque in a torque meter such as a torque wrench or torque driver that measures torque with a change in the capacitance that constitutes the oscillation circuit. This variable oscillation frequency is directly transmitted as a radio wave, the frequency of the received radio wave is counted as a rectangular wave, and the pre-stored no-load value is subtracted from this count value to convert it into a torque value. This is a wireless digital torque meter that is characterized by displaying

[Effect of idea]

Therefore, according to the present invention, the measurement display of the torque value improves workability and improves workability due to wireless signal transmission using radio waves.
The handling range has been significantly improved, and by incorporating the torque detection section as part of the transmitter's oscillation circuit and using an unmodulated carrier wave, there is no need for a V/F converter, modulation circuit, demodulation circuit, etc. Both the transmitter and the receiver can be configured with simple electronic circuits, resulting in low power consumption, simple circuits, and can be made smaller, lighter, and less expensive, making them more practical and requiring less maintenance. This has the effect of providing a torque meter that can be simplified and simplified.

In addition, the oscillation frequency at no-load is memorized, and by subtracting the no-load frequency from the frequency that changes when torque is applied, the oscillation frequency is converted to a torque value.
Point adjustment can be performed simply by re-inputting the frequency at no load, and gain adjustment can be performed simply by changing the time interval at which the oscillation frequency is counted.

[Brief explanation of drawings]

The drawings show an embodiment of the present invention, and FIG. 1 is a structural diagram of a torque wrench, FIG. 2 is a Y-Y sectional view of FIG. 1, FIG. 3 is an explanatory diagram of torque detection, oscillation and transmission circuits, and 5 is a plan view of a torque wrench with a transmitter attached thereto, and FIG. 6 is a side view thereof. 1...torque wrench, 2...grip tube, 3...spanner body, 4, 5...electrode, 6...capacitor,
7... Case, 8... Power switch, 9... Oscillation circuit, 10... Pass/fail determination switch, 11... Triple multiplier circuit, 12... Transmitting antenna, 13... Receiving antenna, 14... Antenna tuner, 15...1st
Local oscillator, 16... First frequency converter, 17...
... Band pass filter, 18 ... Second local oscillator, 19 ... Second frequency converter, 20 ... Waveform shaping circuit, 21 ... Counter circuit, 22 ... Microcomputer, 23 ... Display.

Claims (1)

[Scope of utility model registration request] The oscillation frequency is changed by replacing the amount of mechanical displacement caused by applying torque with a torque meter, such as a torque wrench or torque driver, as a change in the capacitance that makes up the oscillation circuit. It is characterized by directly transmitting radio waves and counting the received radio wave frequency as a rectangular wave, subtracting a pre-stored no-load value from this count value, converting it to a torque value, and displaying it. Wireless digital torque meter.