GB2089053A - Measuring loads - Google Patents

Abstract

A load-measuring means for monitoring forces applied to a part during operation comprises a shaft (6) mounted for example between two pedestals (4), a rotary part (8) in the form of a sheave, pulley or the like mounted on the shaft, which part (8) is normally subjected to radial loading, and strain gauges (14) mounted on or in the pedestals themselves. Indicating means are provided to indicate abnormalities in the loading, and a safety trip switch may be included. <IMAGE>

Description

SPECIFICATION Improvements in or relating to loading measuring means The invention is concerned with improvements in or relating to load measuring means.

It is frequently necessary to monitor the stress applied to a component during operation, for sxample to a rotating part such as a pulley, roller, gear wheel, sheave or drum, which is subjected to considerable strain through engagement with drive belts or chains, or meshing with driving wheels and gears. Advantageously, levels of strain may be monitored in order to detect mal-functioning or overloading for some other reason and the appropriate remedial steps taken.

The invention therefore provides load measuring means comprising a shaft mounted in at least one pedestal secured to a rigid substrate, a rotary part mounted for rotation with respect to the pedestal(s), said rotary part being normally subjected to strain exerted in a substantially radial plane with reference to its axis of rotation, and strain measuring means mounted on or in said pedestals whereby to monitor strain on said rotary part, indicating means being also provided to indicate abnormalities in the exerted strain.

Hitherto it has been the practice to monitor strain by placing strain gauges or the like on a shaft which supports a rotary part, such as, for example, a pulley wheel. Overload on the wheel results in sufficient deformation in the shaft to enable a signal to be produced to indicate the excessive loading. However, the replacement of the shaft involves the replacement and re-setting of the gauges with all the consequent expense and delay. It has been found that if the arrangement according to the invention is adopted, the replacement of parts and access to the gauge means is greatly facilitated.

It will be appreciated that the pedestals must be constructed of material capable of withstanding the stresses imposed upon it and it may be found that some cast components are too brittle.

Conveniently the indicating means is a meter, which may be of the portable variety, provided with a visual read-out dial or display. Advantageously control means may be provided which will, on receipt of a signal indicating an abnormally high loading, trip a cut-out device to prevent continued operation of the strain-producing machinery until remedial action has been taken.

There will now be described an example of the application of the invention to a pulley wheel. It will be understood that the description, which is to be read with reference to the drawings, is given by way of example only and not by way of limitation.

In the drawings Figure 1 shows a view in side elevation of a pulley wheel mounted with respect to pedestals according to the invention; and Figure 2 is a plan view of the assembly of Figure 1.

A frame 2 is secured to the floor of a works location and comprises two bars on each of which is mounted a steel pedestal 4. Spanning the pedestals is a shaft 6 having each of its two ends secured in an appropriate one of the pair of pedestals. A pulley wheel 8 is mounted for rotation about the shaft 6 and has a peripheral groove 10 which receives a steel wire rope 12.

In operation, overload stresses, resulting from some abnormality in operation of machinery with which the steel rope 12 is associated, are transmitted to the pedestals and are monitored by strain gauges 14, set in the pedestals themselves. The strain gauges are connected by leads 16 to a control box C, which in the present example has a dial or other visual read-out means (not shown) to enable an observer to check the reading and has also a tripswitch capable of halting the said machinery in the event of a severe or prolonged overload signal. Thus the arrangement may act as a safety device.

While the above description concerns the use of the invention with a pulley wheel, it will be appreciated that the invention may be applied to any suitable rotary part, such as a sheave, pulley, drum or gear wheel.

Various modifications may be made within the scope of the invention.

1. Load measuring means for monitoring stress applied to a part during operation, comprising a shaft mounted in at least one pedestal securable to a rigid substrate, a rotary part mounted for rotation with respect to the pedestal(s), said rotary part being normally subjected to strain exerted in a substantially radial plane with reference to its axis of rotation, and strain measuring means mounted on orin said pedestal(s) whereby to monitor strain on said rotary part, indicating means being also provided to indicate abnormalities in the exerted strain.

2. Load measuring means as claimed in claim 1, comprising a frame for supporting two pedestals, end portions of the shaft being rotatably mounted in respective ones of said pedestals, said rotary part comprising a pulley wheel or sheave.

3. Load measuring means as claimed in claim 2, wherein the strain measuring means comprise strain gauges mounted on each pedestal adjacent the end portion of the shaft.

4. Load measuring means as claimed in any of the preceding claims, wherein the indicating means further includes switch means capable of operation when the strain detected by the strain-measuring means reaches a predetermined level or persists for a predetermined period of time.

5. Load measuring means as claimed in any one of the preceding claims, wherein the indicating means includes a visual read-out device.

6. Load measuring means for monitoring stress applied to a part during operation, constructed arranged and adapted to operate substantially as hereinbefore described with reference to and as shown in the drawings.

The drawing originally filed was informal and the print here reproduced is taken from a later filed formal copy.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (6)

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION Improvements in or relating to loading measuring means The invention is concerned with improvements in or relating to load measuring means. It is frequently necessary to monitor the stress applied to a component during operation, for sxample to a rotating part such as a pulley, roller, gear wheel, sheave or drum, which is subjected to considerable strain through engagement with drive belts or chains, or meshing with driving wheels and gears. Advantageously, levels of strain may be monitored in order to detect mal-functioning or overloading for some other reason and the appropriate remedial steps taken. The invention therefore provides load measuring means comprising a shaft mounted in at least one pedestal secured to a rigid substrate, a rotary part mounted for rotation with respect to the pedestal(s), said rotary part being normally subjected to strain exerted in a substantially radial plane with reference to its axis of rotation, and strain measuring means mounted on or in said pedestals whereby to monitor strain on said rotary part, indicating means being also provided to indicate abnormalities in the exerted strain. Hitherto it has been the practice to monitor strain by placing strain gauges or the like on a shaft which supports a rotary part, such as, for example, a pulley wheel. Overload on the wheel results in sufficient deformation in the shaft to enable a signal to be produced to indicate the excessive loading. However, the replacement of the shaft involves the replacement and re-setting of the gauges with all the consequent expense and delay. It has been found that if the arrangement according to the invention is adopted, the replacement of parts and access to the gauge means is greatly facilitated. It will be appreciated that the pedestals must be constructed of material capable of withstanding the stresses imposed upon it and it may be found that some cast components are too brittle. Conveniently the indicating means is a meter, which may be of the portable variety, provided with a visual read-out dial or display. Advantageously control means may be provided which will, on receipt of a signal indicating an abnormally high loading, trip a cut-out device to prevent continued operation of the strain-producing machinery until remedial action has been taken. There will now be described an example of the application of the invention to a pulley wheel. It will be understood that the description, which is to be read with reference to the drawings, is given by way of example only and not by way of limitation. In the drawings Figure 1 shows a view in side elevation of a pulley wheel mounted with respect to pedestals according to the invention; and Figure 2 is a plan view of the assembly of Figure 1. A frame 2 is secured to the floor of a works location and comprises two bars on each of which is mounted a steel pedestal 4. Spanning the pedestals is a shaft 6 having each of its two ends secured in an appropriate one of the pair of pedestals. A pulley wheel 8 is mounted for rotation about the shaft 6 and has a peripheral groove 10 which receives a steel wire rope 12. In operation, overload stresses, resulting from some abnormality in operation of machinery with which the steel rope 12 is associated, are transmitted to the pedestals and are monitored by strain gauges 14, set in the pedestals themselves. The strain gauges are connected by leads 16 to a control box C, which in the present example has a dial or other visual read-out means (not shown) to enable an observer to check the reading and has also a tripswitch capable of halting the said machinery in the event of a severe or prolonged overload signal. Thus the arrangement may act as a safety device. While the above description concerns the use of the invention with a pulley wheel, it will be appreciated that the invention may be applied to any suitable rotary part, such as a sheave, pulley, drum or gear wheel. Various modifications may be made within the scope of the invention. CLAIMS

1. Load measuring means for monitoring stress applied to a part during operation, comprising a shaft mounted in at least one pedestal securable to a rigid substrate, a rotary part mounted for rotation with respect to the pedestal(s), said rotary part being normally subjected to strain exerted in a substantially radial plane with reference to its axis of rotation, and strain measuring means mounted on orin said pedestal(s) whereby to monitor strain on said rotary part, indicating means being also provided to indicate abnormalities in the exerted strain.

2. Load measuring means as claimed in claim 1, comprising a frame for supporting two pedestals, end portions of the shaft being rotatably mounted in respective ones of said pedestals, said rotary part comprising a pulley wheel or sheave.

3. Load measuring means as claimed in claim 2, wherein the strain measuring means comprise strain gauges mounted on each pedestal adjacent the end portion of the shaft.

4. Load measuring means as claimed in any of the preceding claims, wherein the indicating means further includes switch means capable of operation when the strain detected by the strain-measuring means reaches a predetermined level or persists for a predetermined period of time.

5. Load measuring means as claimed in any one of the preceding claims, wherein the indicating means includes a visual read-out device.

6. Load measuring means for monitoring stress applied to a part during operation, constructed arranged and adapted to operate substantially as hereinbefore described with reference to and as shown in the drawings.

The drawing originally filed was informal and the print here reproduced is taken from a later filed formal copy.