US139224A

US139224A - Improvement in variable cut-offs for steam-engines

Info

Publication number: US139224A
Authority: US
Publication date: 1873-05-20
Anticipated expiration: 1890-05-20

Description

UNITED STATES PATENT Orrrcnl WILLIAM WRIGHT, on NEW YORK, N. Y.

IMPROVEMENT IN VARIABLE CUT-OFFS FOR STEAM-ENGINES.

Specification forming part of Letters Patent No. 139,224, dated May 20, 1 .873; application filed V January 4, 1873.

To all whom it may concern:

Be it known that I, WILLIAM WRIGHT, of the city, county and State of New York, have invented an Improvement in Variable Cut- Oft's for Steam-Engines, of which the followin g is a specification:

This invention relates to the engine cut-offs, controllable by the governor, and in which the cut-off valves, that may also be the induction ones, are actuated by a variable tappet motion. The invention consists in a combination of peculiarly. constructed and reversely arranged vibrating valve-lifters, also capable of longitudinal motion relatively with the axis tion-valves, one to each end of the cylinder and both of grid construction, although they may be of any other suitable description, it only being important, so far as the novelty of this invention is concerned, that each valve is independent of the other and that they are capable of being separately lifted and of being suddenly dropped to let steam on to opposite ends of the cylinder, and to out it off therefrom at difi'erent points in the stroke of the piston. G U are the exhaust-valves of the engine. These valves, which may also be grid ones, are operated by a longitudinally reciprocating rod, b, deriving its motion from a crank or arm, 0, fast to a rock-shaft, d, which is vibrated by a lever, e, that receives its motion by an eccentric from the main shaft of the engine. The same eccentric actuates both the induction and exhaust valves; but, while the latter have a positive motion, that is-have no variable action-the induction-valves are capable of a variable action, subject to the control of the governor. Thus, on the rock-shaft d is an arm, f, which has pivoted to it a link,

g, that is cross-jointed to an arm, h, on a shaft,

B, arranged to run longitudinally along the side of the engine. This shaft is capable both of a rocking motion in its bearings '13 t, and of a longitudinal or sliding movement therein.

Said shaft D has upon it the lifters E E, which B B earlier or later in the stroke, according to the work demanded of the engine. The axial lines of the valve-stems l l are here repre sented as intersecting the axial line of the rock-shaft D; but this is not a necessary arrangement, inasmuch as said stems might be laterally arranged in relation with. the shaft; but in any case the lifters E E are arranged on reverse sides of the rock-shaft D to alternate the action of the valves. The rocking motion of the shaft D is continuous, but its longitudi nal movement is restricted to variations in the cut-off action of the valves B B. To insure a perfect and desirable action of the lifters E E and of certain jointed toe-piecesm m, attached to the toes F F on the valve-stems, by which the lifters operate the valves B B, each of said lifters is constructed as follows: They are not simply eccentric to the shaft D, but are oblique in direction of their length along their outer or acting edge it, relatively to the axial line of the shaft D, and said outer edge of a spiral configuration lengthwise of the lifter upon a transversely-curved upper surface of said edge struck from a center or centers which bears a lateral relation to the shaft D. The.

throughout their whole width toor as they leave the outer sharp edge of the lifters. The obliquity and pitch of the acting surfaces at of the lifters E determine the sensibility ofthe cut-off.

In the operation of the cut-off, the rocking motion of the shaft D causes thelifters E E to alternately lift the valve B B, and thereby to admit steam alternately to opposite ends of the engine cylinder, but as soon as the acting edges n of the lifters pass from under the pieces m, the period of which, in the stroke of the engine, will be determlned by the longitudinal adjustment of the shaft D and its attached lifters, the valves B B, drop and cut off further supply of steam to the engine. Any suitable cushioning means may be used for easing the drop of said valves.

, What is here claimed and desired to be secured by Letters Patent, is

WM. WRIGHT.

Witnesses.

HENRY T. BROWN, MICHAEL RYAN.