US29604A - Island - Google Patents

Description

UNITED STATES PATENT oEEroE.

PATRICK KENNEY, OF' PROVIDENCE, RHODE ISLAND.

VALVE- GEAR FOR STEAM-ENGINES.

Specification of Letters Patent No. 29,604, dated August 14, 1860.

T o all whom 'it may concern:

Be it known that I, PATRICK KENNEY, of the city and'county` of Providence and State of Rhode Island, have invented a` new and useful Improvement in the Va-lve-Gear of Steam-Engines;- and I do hereby declare that. the following is a full, clear, and exact description of the same, reference being had to the accompanying drawings, forming part of this speciiicatiomin which- F igure l represents a side elevation partly in section of a horizontal engine with my improvement. Fig. 2 is a plan of the same.

Similar letters of reference indicate corresponding parts in both figures.

My invention consists in a novel arrangement of two tripping bars connected with the rock-shafts which carry or operate two induction valves which admit steam to opposite ends of the engine cylinder, in combination with a single rocker having an adjustable toe whereby the induction of the steam is enabled to be effected in a positive manner at the commencement of the stroke of the piston andthe cutting olf is enabled to be effected at various points in the stroke of the piston under the control of a governor or of suitable means of adjustment by the hand of the engineer.

To enable others skilled in the art to make and use my invention I will proceed to describe its construction and operation.

A, is the framing or bed plate of the engine; B, the cylinder S, the steam chest; C, the crank shaft; D, the crank; E, the connecting rod, and F, the piston rod, all arranged applied and operating in the usual manner.

Gr, G, are two rock shafts which are represented as the axles of two rolling induction valves fitted to suitable seats within the steam chest, but which may be arranged in a similar manner, passing through stutling boxes in the steam chest, with suitable connections to work two flat slide valves or puppet valves suitably applied to effect the induction of steam by their opening and the cutting o of the steam by their closing, one valve communicating with the cylinder at one end and the other at the other end. Each of the said rock shafts is furnished outside the steam chest with two arms H, and J; the arms H, I-I, having connected with them by rods I, I, springs K, K, or weights which operate to close the valves and the arms J, J, having each connected with it by a pin joint a, one end of one of the two tripping bars L, L. These tripping bars are directed toward each other from the arms J, J. They occupy nearly horizontal positions and except during a portion of their operation are supported in fixed guides M, M, in which they are held by springs Z), b, pressing on their upper sides. The under sides of the saidbars have a downward inclination towardv their .adjacent extremities-that is to say the opposite extremities to those which connect with the arms J, J, as shown at z', i, in Fig. l.

N, is the rocker by which the tripping bars are acted upon, to produce the motion of the valves, consisting of a lever working on a fixed fulcrum c, arranged below and at equal distances from the two valve rockshafts. rlhis lever is connected by a rod P, with an eccentric O, or cam on the crank shaft,` and its upperV arm is fitted with the sliding toe cl, to which a spring e, is. applied within the arm in such a manner as to force it outward beyond the end of said arm. The distance to which the endy of the saidtoe is forced outward is controlled by a cord or chain g, which connects the said toe with a pin or roller f, which is fitted to suitable bearings said cordv or chain being connected from the toe to the roller and vice versa, between two rollers t, It, which are attached to the fixed fulcrum c, ofthe rocker one at each side of the fulcrum c, so that the cord or chain is not aifected by the motion of the rocker. The rocker f, may be connected with a governor in such a manner that it will wind up t-he cord and so draw the toe CZ, into the arm as the speed of the engine begins to increase, and will unwind the cord and permit the spring to force out the toe as the speed of the engine begins to diminish, or it may be adjustable by hand to draw in or let out the toe. Any other contrivance for drawing in or letting out the cord or chain may be substituted for the pin or roller Then the two valves are closed the tripping bars are held down upon the guides M, M, by the springs o, o, and the opposite ends of the two bars are nearly in contact with each other. The rocker in moving in either direction comes in contact with the inclined portion z', of one bar and lifts it out of its way without disturbing the valve with which the said bar is connected but at or just before the termination of the stroke of the piston rod it comes in cont-act with the end of the other bar and so pushes it along before it on its guide M, in such manner as to make it move the arm, J, and rock shaft in a direction to open its respective induction valve, till the toe d, by its movement from the center of the fulcrum pin 0, escapes from the end of the bar and leaves the valve under the influence of the spring K, or Weight Which instantly closes it and cuts o the steam, the tripping bar L, being carried back by the movement of the bar J, With the closing movement of the valve rock shaft.

In Fig. 1 of the drawing the upper end of the rocker is supposed to be moving to the left and is represented in black outline With its toe as having just raised the right hand tripping bar out of its Way and come in contact With and commenced moving the left hand tripping bar to the left and so commenced opening the left hand valve; but it (the rocker) is shown in red outline as having moved on far enough to have escaped from the tripping bar and thus permitted the valve to close, and the levers and tripping bar are represented in red outlines to correspond. /Vhen the toe escaped from the right hand tripping bar in the above lmovement the latter was caused by its spring ZJ, to drop down upon its guide M, as shown in red outline in the same figure, so that as the rocker returns, its toe may come in contact With that tripping bar and open the right hand valve. The tripping bars are never raised from their guides but held down by their springs during the operation of their respective valves, and the tripping is effected entirely by the end of the toe being carried out of range with the said bars by its movement in a circle; but each' bar is raised by the rocker as the latter after having operated its respective valve is moving back to a position to come into operation on the other bar. It is obvious that the farther the toe is forced out the farther it will move before escaping from the tripping bars and vice versa, and hence the point of cutting off is regulated by the distance the toe projects from the rocker.

If the toe is controlled by a permanent adjustment of the cord g, (or chain) the tripping movement must take place Within or a very little beyond the rst half stroke of the piston for as the rocker begins to change the direction of its motion at about the -half stroke of the piston the tripping bars Will move back slowly With it unless they had escaped before its motionwas reversed; but when a governor .is used in connection With the cord or chain the governor may act upon the band to draw` in the toe and so liberate the tripping bar While the rocker is moving back with the end of the bar in contact with it.

If the tripping bars are made heavy enough, the springs may be dispensed with, as there is no tendency to raise them produced by the action of the toe against their ends in operat-ing the valve. The eduction valves and the mechanism for Working the same to operate in connection With this valve gear may be of any Well known or suitable kind.

/Vhat I claim as my invention and desire to secure by Letters Patent is The arrangement of the tWo tripping bars L, L, jointed to arms of the valve rockshafts and Working on guides or stops M, M, .in combination With the single rocker N, and its adjustable toe (l, t-he Whole operating substantially as herein described.

PATRICK KENNEY.

Vitnesses:

JOHN J. BRENNAN, STEPHEN MARTIN.

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