US72192A - Improvement in steam safety-yalyes - Google Patents

Description

VIRGIL D. GREEN, OF WATERTOWNQ;WISCONSIN, ASSIGNOR T() HIMSELF AND E. M. HALL.- OF THESAME' PLACE.

Letters Patent No. 72,192, dated December 17, 1867.

IMPRVBMBNT 1N STEAM SAFETY-VALVES.

TO ALL WHOM IT MAY CONCERN:

Be it known that I, VIRGIL D. GREEN, of Watertown, in the county of Jeii`erson','and State of Wisconsin, have invented a new and useful Improvement in AEquilibriutn- Balance for Safety-Valves; and I do hereby declare` that the following is a full, clear, and exact descriptionthereof, which will enable others skilled in the art to make and use the saine, reference being had to the accompanying drawings, forming part of this specification.

'.Lhe object'ot' this invention is to overcome the rigidity ofthe spring in the spring-balances in common use. It is well understood that, as the lever of the safety-valve is raisedgthe tension, and consequently the rigidity, of the spring increases in proportion as the lever is raised; andthe invention consists in providing a cylinder which contains a barrel with a spiral spring within it, and withacam'and chain -attached, whereby I am enabled to overcome the diiliculties hitherto met with in 'properly regulating the safety-valve, as will hereinafter be described. Y

And to enable others skilled in the art to make and use myinventiorn-I will proceed to describe its construction and operation.

Figure 1 represents a top view of my balance with the cap oil'.

Figure 2 is a central longitudinal section through the line :v :v of fig. 1; and

Figure 3 is asection of the barrel through thevline y y, showing` the spiral spring and its fastenings. l,

Similar letters of reference indicate like parts. i

A represents the'eylinder; B, the barrel containing thespring. C isa central shaft. D is aratehet-wheel on the shaft. E isthe safety-valve lever. F is the rod which connects the balance with the safety-valve lever. H is a chain, which connects the rod F to the barrel Br G is the spiral spring, attached to the shaft and tothe barrel, as seen in fig. 3. The ratchet is attached to tbe sliziftand is held by a spring-peril, which is attached to the bottom of the cylinder A. It is seen in dotted lines in tig. 1, and represented by p.' Thespring is wound up in the barrel by a key, which fits thertop'of the shaft, as seen in iig. 1. Upon theupper end of the barrel B there is a cam, m, to the side of which the chain H is attached, the Aother end of thechain being connected to I the end of the rod Il',V after passing round the cam, asA seenin iig. 1.

It will be seen that the chain is attached to the cam at a point which is farther frein the centre ofthe shaft than the point occupied bythe other end where itis connected to the rod F.

The balance being set, as represented in iig. 1, any addition to the strain or rigidity of the spring serves to increase the leverage or distance from the centre to the point ofV resistance, and, consequently, counteracts the increasing rigidity, by operating with a longer lever. In other words, the power to coil the spring, and which increases its rigidity, is applied where the tangent loaves the cam, and the rod F is the tangent.

Having thus described my invention, what I claim as new, and desire to secure by Letters Patent, is-'- The cylinder A, the drum B, the spring G, the ratchet and pawl Dp, in combination withithe cam m and the chain H, substantially as described. f

VIRGIL D. GREEN.

Witnesses WALDo LYON, SAMUEL MeMULLIN.

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