Emerson's power scales, or dynamometer

✍ Scribed by Jesse H. Lord

• Book ID: 103089294
• Publisher: Elsevier Science
• Year: 1882
• Tongue: English
• Weight: 252 KB
• Volume: 114
• Category: Article
• ISSN: 0016-0032
• DOI: 10.1016/0016-0032(82)90245-9

✦ Synopsis

A number of attenlpts have been made to construct a power measurer which should give absolute results in foot-pounds; but most of them had some inherent defect, either in construction or application. Some' have depended upon springs for efficiency, others have been intended for fixtures; most of them gave only relative results, and none of them were simple, portable, easily applied attachments, So many mechanics insist on a resort to the Prony brake as preferable to any and all so-called improvements. Yet a good dynamometer is unquestionably to 1)e desired, as a useful implement to the manui~ac ,turer, millwright, the leasor, and to the hirer of power. James Emerson, of WilHmansctt, Mass., has perfected a power scale that appears to possess all the requisites desired. Unlike most other power measurers, this demands no change in the machine or shaft to which it is applied, beyond the removal of one of the pulleys, if a tight and loose pulley are used, the pulley=arms serving as means of propulsion or actuation of the power measurer. No springs are used on the machine, and all the movements are direct and absolute. No comparison with some other standard is required, as this machine gives absolute resultsdnstead of relative indications. It short, it is a power scales, and really weighs the "strain," "resistance," "friction," or " inertia," iust as truly as the Fairbanks scales weighs the gravity of a load; and, like the Fairbanks scales, this may be considered a standard. The ele~nents of its operation are speed of the machine, to be weighed or measured in feet, and resistance of the machine in avoirdupois pounds. Both these data are given by the appliance at the same time, and both are represented in plain figures. The result of the two multiplied together is the number of ibot-pounds, which may be easily reduced to horse-power or its tractions if this is desired.

The larger engraving represents the power scale detached, and the smaller engraving shows it attached to a machine from which the loose pulley has been removed, and the tight pulley is made a loose pulley by having its set-screw slacked up or its key removed. The utility of this remaining pulley is to receive the driving belt, that the machine to be tested may be run at its normal speed.