SU1740993A1 - Device to test a vibrating toolъs handle vibrational amplitude effecting an operatorъs hand - Google Patents

Abstract

The invention relates to devices for measuring parameters of local vibrations acting on the hands of an operator when operating with a manual vibrotool. The aim of the invention is to improve the measurement accuracy. The device comprises a housing 1 and vibration transducers 6 intended for fastening on the vibrotool. The housing 1 is made in the form of an overlay intended to extend the handle 2 of the vibrotool along its entire length and having a cavity in which the vibro transducers 6. are located. 2 Il.

Description

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The invention relates to devices for measuring the amplitude of vibration of a handle of a vibrotool when it is exposed to the hand of an operator when operating with a manual vibrotool (chipping, riveting or jackhammer, rammer, etc.).

A device for measuring vibrations during operation with various vibrating equipment (vibrating tables, turbines, etc.), which is rigidly attached to their shells, is known.

The closest in technical essence to the proposed device is the measurement of local vibrations on the handle of a hand-held vibrotool, containing a vibro-transducer (accelerometer), which is attached to the vibrotool handle by means of a transition element — a housing. The housing has three mutually perpendicular threaded holes for fastening the vibrator when measuring the parameters of vibrations acting in three mutually perpendicular directions along the axes of these holes.

In this case, the housing is rigidly fastened to the handle of the vibrotool, usually with the help of clamps.

In order to ensure the accuracy of measurements carried out in frequency bands, in the range of 8-1000 Hz, the natural frequency of vibration of the vibration transducer, fixed with the housing, must be at least 2000 Hz.

This condition can only be fulfilled when the case is fixed on the rigid handle of the vibrotool. A vibrotool is known, the handle of which is designed to reduce the level of local vibrations affecting the hands of the operator and is covered with a layer of vibration damping material (polyurethane foam, porous rubber, etc.).

When mounted on the handle of such a tool body with vibration transducers, their own oscillation frequency due to a sharp decrease in the fastening rigidity decreases to values in the range of vibration parameters measurement.

In this case, in the process of measurements, the vibration of the housing with the vibration transducer at its own frequency increases sharply due to resonance. At the same time, the results of measuring the amplitude of vibrations do not correspond to the vibrations transmitted to the hands of the operator, but are substantially overestimated.

In addition, in the process of measuring the vibration amplitude of the vibrotool handle when it is acting on the arm

the operator can use only the part of the handle that remains free of the casing attached to it with a vibration transducer, which is

serious inconvenience when taking measurements.

The purpose of the invention is to improve the measurement accuracy.

For this purpose, a device for measuring the amplitude of the vibration of the handle of the vibrotool when it is exposed to the operator’s hand contains a housing intended for mounting on the vibrotool and vibration transducers. The body is made as

5 pads designed to cover the handle of the vibrotool along its entire length and having a cavity in which vibration transducers are placed.

FIG. 1 shows the device, the general view; in fig. 2 is a section A-A in FIG. 1. The device comprises a box-shaped body 1, designed to be fixed on a vibrotool and made in the form of a lining covering the handles 2

5 vibrotools along its entire length. The housing 1 has a cavity, at the base and side walls of which there are three mutually perpendicular threaded holes 3, A and 5 for fastening the vibration transducer

0 6 (figs, 1 and 2),

The housing 1 is fixed on the handle 2 of the vibrotool with a clamp 7, screwed down with screws 8 and nuts 9. Surface 10

5 (Fig. 2) of the housing 1 is curved in shape corresponding to the shape of that portion of the handle 2 of the vibrotool to which the housing 1 adjoins when mounted.

0Surface 11 body 1 for convenience

work has a rounded shape.

Wall 12 (Fig. 1) of housing 1 to facilitate fixing of the vibration transducer and reducing housing dimensions in height

5 can be made removable. In this case, during the measurements of the amplitude of vibration, it is rigidly attached to the housing 1, for example with screws (not shown).

0, the vibration transducer 6 is successively secured to each of the threaded holes 3, 4 and 5 during the measurement. The operator applies a static pressing force on the vibrotool to the body 1,

5 which in this case acts as an additional handle and is an intermediate part for transmitting the pressing force from the operator's hand to the handle 2 of the vibrotool.

At the same time, free oscillations of the housing 1 with the vibration transducer 6 at their own (resonant) frequency are damped by the operator’s hand, pressing the housing 1 to the handle 2 of the vibrotool, as a result of which the parameters of the measured vibration amplitude of the handle fully correspond to the vibrations affecting the operator’s hand, i.e. . the results of the measurements are reliable.

The case design in the form of a lining does not prevent the operator to hold the handle of the vibrotool, i.e. convenient for measuring the amplitude of vibrations.

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Claims (1)

Apparatus of the Invention A device for measuring the amplitude of vibration of a handle of a vibrotool when it is exposed to an operator’s hand, comprising a housing for mounting on a vibrotool and vibration transducers, characterized in that, in order to improve the measurement accuracy, the housing is designed as an overlay designed to surround the vibration vibration of the handle along its entire length and having a cavity in which vibration transducers are placed. / I -4 FIG. 2