RU2248543C2 - Force measuring unit - Google Patents

Abstract

FIELD: measurement technology; measurement of loads in kinematic and force transmitting members.

SUBSTANCE: proposed device has upper and lower flat members with holes in their centers. Force sensing member located between these flat members is made in form of rigid metal plate provided with projection in its center for taking-up forces. Upper and lower surfaces of this metal plate are provided with sections of current-insulated strain-sensitive wire. Sections of wire are preliminarily deformed by compression force.

EFFECT: enhanced sensitivity; possibility of measuring alternating forces.

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Description

The invention relates to measuring equipment, and in particular to devices designed to measure loads in various kinematic and power-transmitting links, not allowing an increase in the length of the chain or link.

A device for measuring loads [1], containing flat annular force-sensing elements, between which is placed an elastic element (strain element), the latter is made of a thin metal plate and open sections of an insulated strain-sensitive wire. The disadvantage of this device is the low sensitivity and the inability to measure alternating forces.

The closest (prototype) in technical essence to the proposed invention is a solution [2]. According to this solution, in a sensor containing two force-sensing elements with holes in the center, between which an elastic element is placed in the form of a section of a current-insulated strain-sensitive wire. The disadvantage of this device is a large additive temperature error, low sensitivity and the inability to measure alternating loads.

The objective of the invention is to increase the output signal (increase sensitivity) and provide the ability to measure alternating forces. This is achieved by the fact that in the device for measuring forces, containing the upper and lower flat elements with holes in the center, with sections of a current-insulated strain-sensitive wire installed between them, a force-sensing element is placed between the flat elements, made in the form of a rigid metal plate provided with a protrusion in the center for the perception of the measured effort, on the upper and lower surfaces of the metal plate are installed sections of the insulated strain-sensitive wire, while sections are pre-deformed by compression force, for example with screws, when the output signal is zero.

The implementation of the power-sensing element in the form of a rigid metal plate provided with a protrusion in the center provides the perception of the measured force during the transmission and transformation of the input signal.

Placing a current-insulated strain-sensitive wire on the upper and lower surfaces of the metal plate and preliminary deformation of these sections by compressive force provides an increase in the output signal and measurement of alternating forces.

The drawing shows the design of the device.

The force measuring device consists of an upper 1 and a lower 2 flat elements, between which a force-sensing element is installed - a rigid metal plate 3. On the upper surface of the force-sensing element, sections 5 and 7 of the insulated strain-sensing wire are installed, on the lower surface are sections 6 and 8 of the insulated strain-sensing wire. For compression deformation when setting the zero of the output signal, clamping screws 4 are provided.

The pulling force should correspond to the upper value of the force measuring range.

The device operates as follows.

Initially, in the absence of effort, all sections of the insulated strain-sensitive wire were subjected to compression deformation, and the output signal was zero. Thus, the minimum value of the electrical resistance of all sections of the insulated strain gauge wire is established. When a force is applied, for example, downward, the sections of the current-insulated strain-sensitive wire 5 and 7 undergo tensile strains, their electrical resistance increases, and the sections of the current-insulated strain-sensitive wire 6 and 8 — compression deformations, their electrical resistance decreases. When an upward force is applied, the sections of the current-insulated strain-sensitive wire 5 and 7 undergo compression deformations, and their electrical resistance decreases. The sections of the current-insensitive strain-sensitive wire 6 and 8, subjected to tensile deformation, increase their electrical resistance.

A positive result is achieved by the fact that all sections of the insulated strain gauge wire are included in the bridge measuring circuit so that they comprise four working arms of the bridge, this achieves a twofold increase in the output signal, and the introduction of deformation of the sections of the insulated strain gauge wire by compressive force when the output signal is set to zero ensures measurement of alternating force.

Sources of information

1. RU, application for invention No. 2002105298/20 of 02.26.02.

2. Patent of Russia №2010192, cl. G 01 L 1/22, bull. No. 6 of 03.30.94.

Claims (1)

A device for measuring forces, comprising upper and lower flat elements with holes in the center with sections of a current-insulated strain-sensing wire installed between them, characterized in that a power-sensing element is placed between the flat elements, made in the form of a rigid metal plate equipped with a protrusion protrusion in the center, sections of a current-insulated strain-sensitive wire are installed on the upper and lower surfaces of the metal plate, while these sections are preliminary tionary deformed by compression force.