Measuring and testing – Dynamometers – Responsive to torque
Patent
1993-01-06
1994-08-09
Goldstein, Herbert
Measuring and testing
Dynamometers
Responsive to torque
7386208, 29721, G01L 524
Patent
active
053355563
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
The present invention relates to a tightening fixture for a chuck. More particularly, the present invention relates to a built-in torque readout device for measuring the torque applied to tighten the lock nut of a chuck.
In high speed tooling, it is important to tighten the lock nut of a chuck to a specified torque. If the lock nut is not tightened sufficiently, the tool may come loose during operation posing a hazardous threat to anyone standing nearby. On the other hand, over-tightening may cause damage to the tool or chuck.
Tightening fixtures are currently in use to assist tightening of a lock nut on a chuck. Generally speaking, a tightening fixture comprises a stationary block having an opening formed therein to receive a toolholder or chuck. Typically, the toolholder will include a flange having one or more keyways. Keys fixed to the stationary block engage the keyways on the toolholder to prevent rotation of the toolholder, relative to the tightening fixture. Thus, the tightening fixture functions in a manner similar to a vice or clamp to hold the toolholder in a fixed position as the lock nut is tightened.
Currently, there are no tightening fixtures which have the capability of measuring the tightening torque applied to tighten the lock nut on a chuck. Torque is determined by using a conventional torque wrench to tighten the lock nut. However, a torque wrench may not always be available when it is needed. Further, torque wrenches cannot be used in all applications.
SUMMARY AND OBJECTS OF THE INVENTION
The present invention eliminates the need for torque wrenches to measure tightening torque by incorporating a torque measuring device into the tightening fixture.
One embodiment of the torque measuring device of the present invention includes a dial indicator mounted in a stationary block at a predetermined radius from the center of the block. A torque transmitting collar is rotatably mounted in a stationary block and is adapted to receive and hold the chuck. When torque is applied to tighten the lock nut on the chuck, the collar rotates against an actuator rod which in turn pushes against the dial indicator resulting in a corresponding movement of the dial indicator's pointer.
A second embodiment of the torque measuring device includes a cantilevered member with a strain gauge attached to it. The member is mounted in the stationary block and protrudes into a notch in a torque transmitting collar rotatably mounted in the stationary block. The collar is adapted to receive and hold the chuck. By deflection of the cantilevered member caused by rotation of the collar, the applied torque can be determined.
Based on the foregoing, it is a primary object of the present invention to provide a tightening fixture for tightening a lock nut on a chuck having a built in torque measuring device.
Another object of the present invention is to provide a tightening fixture for tightening a lock nut on a chuck which is adapted to receive various sizes of chucks.
Another object of the present invention is to provide a tightening fixture for tightening a lock nut on a chuck having a relatively simple construction with few moving parts.
Another object of the present invention is to provide a tightening fixture for tightening a lock nut on a chuck which is easy to use.
Other objects and advantages of the present invention will become apparent and obvious from a study of the following description and the accompanying drawings which are merely illustrative of such invention.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is an exploded perspective view of a first embodiment of the tightening fixture;
FIG. 2 is a front elevation view of the first embodiment of the tightening fixture with portions thereof shown in sections to illustrate the invention;
FIG. 3 is a section view of the first embodiment of the tightening fixture taken through a plane parallel to the sides of the support block;
FIG. 4A is a perspective view of the torque transmitting collar and adapter plate used in the present invention
REFERENCES:
patent: 2300288 (1942-10-01), Hullhorst
patent: 3044322 (1962-07-01), George
patent: 3232101 (1966-02-01), Siegler
patent: 3448988 (1969-06-01), Athanasiou
patent: 3552198 (1971-01-01), Friedland
patent: 4193720 (1980-03-01), Machida
patent: 4304510 (1981-12-01), Machida
Soviet Engineering Research, (Stanki I Instrumenty & Vestnik Mashinostroenia Mashinostrocnie) vol. 11, No. 7, 1991, New York, USA, pp. 152-153, Yu. Kh. Amirdzhanov, E. A., "Device for Measuring Forces on Machine Tool Control Levers".
Dougherty Elizabeth L.
Goldstein Herbert
Kennametal Inc.
Porcelli James G.
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