SU1679077A1 - Device for measuring axial force in fastening parts - Google Patents

Abstract

The invention relates to mechanical engineering. The purpose of the invention is to expand the technological capabilities of the device by providing measurement of the tightening forces in all their possible range. The device contains an elastic annular gasket 1, a strain gauge 2 mounted on the outer side surface of the gasket 1 and connected to the deformation recorder 3. The area (in cm2) of the cross section SB of the elastic annular gasket is calculated using the formula SB SK ok OB 1. where SK is the transverse area fastener section, cm, ok - the strength of the material of the fastener, kg / cm; STV - the limit of proportionality of the material of an elastic ring groker, kg / cm2. The device allows to provide a reliable dependence of the force on the deformation and, therefore, the accuracy of measurements in the whole possible range of forces. 2 Il. (l c

Description

1

This invention relates to mechanical engineering in devices for measuring and recording axial forces in fasteners.

The purpose of the invention is the expansion of technological capabilities by providing a measurement of the tightening forces in all their possible range.

Fig. 1 schematically shows a device for measuring axial force in fasteners; figure 2 - section aa in figure 1.

The device comprises an elastic annular gasket 1, a deformation sensor 2 mounted on the outer lateral surface of the gasket 1 and connected to the deformation recorder 3.

The device works as follows.

An annular gasket is installed on the fastener between the washer and the surface of the part to be joined. Then fasten the fastener. Axial forces are produced in the fastener, which are transmitted from its head through the washer to the elastic ring gasket 1. The latter is deformed. A strain gauge mounted on its outer side surface senses the structural changes occurring in the part, changing its resistance. This change in resistance is recorded by the deformation recorder 3, and by its magnitude it is judged the force observed in the fastening element. In order to maximize the sensitivity of the force measurement and cover their possible range, the following condition must be met:

Fyn Rraz,

those. The force Fyn acting on the part and causing tension in the part material equal in magnitude to its limit of proportionality should be equal to the tensile strength of the fastener. From this condition, we equate the physical values of these quantities

Fyn SB Oh, raz SK OK,

where SK is the cross-sectional area of the fastener, cm;

Ok - material strength of the fastener, kg / cm;

SB is the cross-sectional area of the sleeve, cm2;

agv - proportionality limit of the hub material, kg / cm.

From here

SB SK Ok Ov 1, CM2.

Before mounting on the fastener, the device is tared.

A strain gauge of the 2PK type is used as the strain sensor, and a 10-channel portable strain gauge of the IDD-1 type (or SRTT-3) is used as the strain gauge.

The use of the present invention will expand the technological capabilities in the measurement of the axial force in the fasteners and improve the measurement accuracy over the entire possible range of forces.

f. Claim device for measuring axial force in fasteners, comprising an elastic annular gasket mounted on a fastener rod, and a strain gauge mounted on the outer side surface of the gasket, connected to the deformation recorder, characterized in that By providing a measurement of the tightening forces in the whole possible range, the ring gasket is made with a cross-sectional area SB equal to

SB SK OK OV 1. CM2.

where SK is the cross-sectional area of the fastener, cm2;

ok is the material strength of the fastener, kg / cm2;

OB is the limit of proportionality of the material of an elastic ring gasket, kg / cm2.

FIG. 2

Claims (1)

Claim A device for measuring axial force in fasteners, comprising an elastic ring gasket mounted on the rod of the fastener, and a strain gauge mounted on the outer side surface of the gasket connected to a strain register, characterized in that, in order to expand technological capabilities by providing force measurements tightening in all their possible range, the annular gasket is performed with a cross-sectional area S _B equal to S _B = S _K · σ _κ · σ _Β · “ ¹ , 0Μ ² , where S _K is the cross-sectional area of the fastener, cm ² ; OK - the tensile strength of the material of the fastener, kg / cm ² ; σ _Β is the proportionality limit of the material of the elastic ring gasket, kg / cm ² . Figure 2 Compiled by I. Khramtsova Editor I. Gornaya Tehred M. Morgenthal Corrector S. Shevkun ...... Order 3195 Circulation 421 Subscription VNIIIPI of the State Committee for Inventions and Discoveries under the State Committee for Science and Technology of the USSR 113035, Moscow, Zh-35, Raushskaya nab., 4/5 Production and Publishing Plant Patent, Uzhgorod, 101 Gagarina St.