GB2057149A

GB2057149A - Weight measuring element

Info

Publication number: GB2057149A
Application number: GB8025596A
Authority: GB
Original assignee: ZWEIWEG FAHRZEUG VERTRIEBS KG
Current assignee: ZWEIWEG FAHRZEUG VERTRIEBS KG
Priority date: 1979-08-10
Filing date: 1980-08-06
Publication date: 1981-03-25
Also published as: JPS56153227A; DE2932597A1; GB2057149B; DE2932597C2; FR2463400B1; FR2463400A1

Abstract

A weight measuring element consists of two deformable end portions 2 and 3, with axial bores 8 therethrough connected by upper resilient joints 6 to an upper beam 1 provided with a load-receiving surface F. The element has vertical slots 10 lying at right angles to its longitudinal axis which open into horizontal slots 11 separating beam 1 from lower anchor tie beam 4 but for optional connecting web 5. Measuring gauges DMS measure the distortion of the end portions 2 and 3 so that a load on surface F can be determined independently of its longitudinal or lateral point of application on surface F. The element may be employed in the rail track of a rail track vehicle to measure the wheel pressure of such a vehicle. <IMAGE>

Description

SPECIFICATION Weight measuring element The invention relates to a measuring element for determining the value of a load engaging in the zone of a surface area by means of measuring gauges which are disposed in the zone of end-face axial bores in the measuring element and form part of an electric bridge circuit, slot-shaped cutaway portions lying at right angles to the longitudinal axis of the measuring element and remote from the surface area receiving the load limiting the axial extension of such bores.

Such a measuring element, disclosed in German Offenlegungsschrift 2758997 takes the form of a mechanical transverse beam whose end parts are made resilient in relation to the central part by means of the slots. When a load is borne, therefore, the end parts open up in relation to the connecting central part, so that no pure shearing forces proportional to the load applied occur at the end parts. The measuring gauges therefore fail to record completely the lines of force occurring in the end parts. Furthermore, the indication of the measuring gauges depends in each case on the axial position of the point at which the force engages the load-receiving surface area, and this results in undesirable changes in the indication of the load when a load is applied which moves over the measuring member, The measuring accuracy is therefore unsatisfactory.Lastly, if a measuring element included in a stretch of rail track ruptures, such measuring element forms for the rail track vehicles using the stretch of track a joint abutment which is impermissible under the safety regulations in force.

It is an object of the invention so to develop the known measuring element that all forces occurring during the operation of a load occur as far as ever possible in the form of pure shearing forces in the end parts, and the load indication is rendered independent of the place at which the load is applied, so as substantially to increase measuring accuracy, while at the same time giving the measuring element a form such that when it is used for measuring the wheel pressure of rail track vehicle, all safety regulations can be met.

Starting from a measuring element of the kind specified, this problem is solved according to the invention by the features that those parts of the measuring element formed with the end-face bores are interconnected adjacent their bearing surfaces via a lower flange which extends parallel with the upper flange having the surface area receiving the ioad, and the connecting zones between the end-face parts and the flanges form resilient joints.

Further features of the invention can be gathered from the sub claims.

The measuring element according to the invention therefore consists of six functional parts, namely: the upper flange acting as a measuring beam; the lower flange acting as an anchor tie beam; the resiliently deformable joints at their end faces; the end-face parts forming substantially annular elements and acting as resilient deformation elements; the measuring gauges disposed on the deformation elements: and if necessary the web acting as a load divider between the measuring and anchor tie beams.

The measuring beam is used exclusively for introducing the load to be measured into the deformation elements and is therefore extremely rigid in construction, so that as far as ever possible only shearing forces are transmitted via the resilient joints between the measuring beam and the deformation elements. The purpose of the anchor tie beam is to prevent the deformation elements from opening up as a result of such loading.By means of the load divider on the one hand a portion of the load applied is taken over by the anchor tie beam, without thereby falsifying the measured value -- since the load divider is disposed precisely in the centre between the deformation elements, it has no influence on the course of the lines of force in the defonnation elements -- while on the other hand the load divider also contributes towards keeping the deformation elements parallel with one another under loading.Due to the bores introduced and the cross-sectional wea kenings of the deformation elements, the latter operate as substantially annular elements, which bear on their inner or outer walls, or inner and outer walls, the measuring gauges connected to form a bridge circuit, the measured value and therefore the accuracy of measurement being enhanced if the measuring gauges are disposed on the inner and outer walls of the deformation elements. The resilient deformation of the deformation elements is therefore a yardstick for the load to be measured, which shows itself as a detuning of the bridge circuit.If one or both upper joints rupture, the distance to which the measuring beam drops is limited by the load divider, but more particularly by the webs of the bores disposed one beside the other, so that when the measuring element according to the invention is used for measuring the wheel pressure of a rail track vehicle there is a guarantee that the rail track vehicle will not be derailed when it passes over a broken measuring element.

The invention will now be described with reference to two embodiments of the measuring element illustrated to a varying degree diagramitically in the drawings, wherein: Fig. 1 is a perspective view of a measuring element according to the invention, and Fig. 2 is a side elevation of a variant embodiment of the measuring element according to the invention illustrated in Fig. 1.

A measuring element ME (substantially in the form of a prismatic member) has in its upper zone, as viewed in Fig. 1, an upper flange 1 which acts as a measuring beam and which is connected to end-face parts 2, 3 acting as deformation elements. The load-receiving surface area of the measuring beam has the reference F. The parts 2 and 3 are interconnected in their lower zone by a lower flange 4 acting as an anchor tie beam. The connecting places between the parts 2 and 3, acting as deformation elements, and the top and bottom flanges act as resilient joints 6. In order that they shall be able to act as deformation elements, the parts 2 and 3 are formed with axial bores 8 extending as far as slots 10 which are each disposed at right angles to the longitudinal axis of the measuring element and extend completely therethrough.The ends of the slots 10 remote from the load-receiving surface area F pass over into slots 11 which extend at right angles to the slots 10 and which are disposed parallel with the longitudinal axis, and which can be bounded in their centre by a web 5 extending transversely to the longitudinal axis. The web 5 connects the measuring beam 1 to the anchor tie -beam 4 exactly in the centre. These slots in the substantially prismatic member are formed by being milled from the solid by means of an endmilling cutter. Finally, the measuring element ME has milled-off portions 12 which extend over the length of the parts 2 and 3 and weaken the cross sections of such parts.On their underside the parts 2 and 3 have varying surfaces 14, and 142 and 15, and 152, whose distances a, and a2 respectiveiy (cf. Fig. 2) determine the measuring length between the deformation elements. The total measuring element is therefore produced from one piece, its individual functional members being formed by openings, bores and milled-off portions respectively.

Attached to the inner walls of the bores 8 of the parts 2 and 3, or to the parallel side walls of the milled-off portions 12, or to the inner walls of the bores 8 of the parts 2 and 3 and to the parallel side walls of the milled-off portions 12 are measuring gauges DMS, which all form parts of a measuring bridge (not shown) whose detuning is a yardstick for the force operative on the measuring beam, more particularly within the surface area F representing the measuring area.

In the embodiment of the measuring element ME illustrated in Fig. 2 the slots 11 are formed by bores 21, the webs between the bores being separated by a slot milling, with the exception of the web 25 in the centre, if a load divider is required in this embodiment also. A central bore 27 of small diameter (shown in chain lines in Fig.

2) is used for the introduction of electric connected wires for the measuring gauges DMS.

Otherwise this measuring element exactly corresponds to the preceding measuring element described in relation to Fig. 1. The webs mentioned have the purpose of limiting to the minimum the distance to which the measuring beam drops if one or both upper joints 6 rupture, so as to prevent the rail track vehicle being derailed if the measuring element described is used for measuring the wheel pressure of rail track vehicles over a stretch of rail.

The measuring element disclosed is able to indicate precisely the value of a normal force if its point of operation lies within the measuring path as embodied by the measuring element. It is immaterial at what point of the measuring path the point of operation lies.

The measuring element disclosed can therefore be used for all purposes, namely in all cases in which loads must be determined with high accuracy in a very simple manner. The measuring element disclosed can be used, for example, for measuring the wheel pressure of rail track vehicles, or as the load-transmitting member of a balance. For this purpose its bearings 141,142, 15, and 152 are conveniently constructed reversible, so that the measuring range can be reversed in a very simple manner. The output of the electric bridge circuit must in that case be connected, for example, to a digital indication device. In the application mentioned at first within a rail track, a measuring element must be inserted coaxially in each of the two rails of the track to be measured, as described and illustrated, for example in German Offenlegungsschrift 27 58 997. In that case the outputs of the electric bridge circuit are conveniently connected to recording and controlling output devices.

Claims

1. A measuring element comprising two axially spaced end portions joined together by an upper beam, the end portions having bores extending axially therethrough and carrying measuring gauges capable of determining distortion of the element due to loading, the element further comprising slots lying at right angles to said axis and remote from an upper surface area of the first beam capable of receiving a load, the slots defining the axially inwards extent of the respective bores, and wherein the end portions have bearing surfaces on their lower faces and are also joined adjacent their lower faces by a lower beam which extends parallel with the upper beam, the connecting zones between the end portions and the beams forming resilient joints.

2. An element according to claim 1 comprising at least two axially spaced bearing surfaces on respective end portions.

3. An element according to claim 1 or claim 2 in which one or more further slots extend between the upper and lower beams and from the firstmentioned slots.

4. An element according to claim 3 in which the or each further slot between the upper and lower beams is formed by parallel bores whose web zones are split so that the bores communicate with one another.

5. An element according to claim 3 or claim 4 in which there are two of said further slots separated by a web extending between the upper and lower beams at right angles to the longitudinal axis and centrally of the upper beam.

6. An element according to any one of the preceding claims in which the slots have been produced by milling.

7. An element according to any one of the preceding claims in which the or some of the measuring gauges are disposed on the inner walls of the bores.

8. An element according to any one of the preceding claims in which the cross section of the element is reduced laterally at the axially spaced end portions.

9. An element according to claim 8 in which the or some of the measuring gauges are disposed on the outer lateral walls of the reduced cross section end portions and adjacent the slots defining the axially inwards extent of the respective bores.

10. An element according to any one of the preceding claims, more particularly for measuring the wheel pressure of the wheel of a rail track vehicle, in which the element is a prismatic member with the upper surface thereof including the upper surface area of the upper beam being arcuate in axial cross section and with the lateral surfaces thereof and the bearing surfaces of the end portions being substantially planar.

11. A measuring element substantially as herein described with reference to FIGURE 1 of the accompanying drawings.

12. A measuring element substantially as herein described with reference to FIGURE 2 of the accompanying drawings.

1 3. Measuring means comprising a measuring element according to any one of the preceding claims in which the measuring gauges form part of an electric bridge circuit.

14. Measuring means according to claim 13 when dependent from claim 2 or any claim appended thereto in which the measuring means is in the form of a balance, the load-transmitting member of which comprises the measuring element, and wherein the bearing surfaces are operative in pairs each of which in any pair is on a respective end portion and each pair providing a different measuring length in the electric bridge circuit, the output of the bridge circuit being connected to an amplifier and an indicating device or recorder.

14. Measuring means according to claim 13 which is in the form of a balance, the loadtransmitting member of which comprises the measuring element, and wherein the operation of the bearing surfaces of the measuring element is reversible in order to reverse the measuring range, and the output of the electric bridge circuit.

is connected to an amplifier and an indicating device or recorder.

New claims or amendments to claims filed on 12 November 1980 Superseded claim 14 New or amended claims: