US16171A - Valve-greab - Google Patents

Description

UNITED STATES PATENT OFFICE.

ALFRED S. BEEBE, OF FALL RIVER, MASSACHUSETTS.

VALVE-GEAR FOR STEAM-ENGINES..

Specification of Letters Patent No.

To all 'whom it may concern:

Be it known that. I, ALFRED S. Bienen, of Fall River, inthe county of Bristol and State of Massachusetts, have invented a new and useful Improvement in Valve-Gear for 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 drawing, forming part of this specification.

This invention is applicable to what is known as Stevenss cutoff, or to other valve gear which operates the valves by toes and lifters. Its main object is to enable the time of closing the induction valve or cut off to be varied, to cut ott the steam at an earlier or later point in the stroke of the piston Without stopping the engine. It may also be applied to the eduction valve, as will be hereinafter explained.

Figure 1, in the drawing, is a sectional elevation of one induction valve and its 'operating gear belonging to Stevenss cutoif, exhibiting the application of my invent-ion. Fg. 2, is a side view of the toe and lifter.

Similar letters of reference indicate corresponding parts in bot-h figures.

A, is the induction valve.

B, is the lifting rod.

O, is the rockshaft for opening the induction valves by the toes and lifters, said rockshaft being actuated in the usual manner.

D, is the toe on the rockshaft and E, is the lifter on the lifting rod, for operating the valve A, the said toe and lifter being, externally, just like the toe and lifter common to Stevenss out o. For the sake of clearness, I will hereinafter speak of t-he toe D, as the main toe to distinguish it from what is hereinafter spoken of as the secondary toe7 which constitutes part of my invention.

I, is t-he secondary toe which is in the form of a lever and is fitted to work on a pivot b, in a recess a, (see Fig. 1) made in the face of the toe, said recess being of just sufficient depth to receive the secondary toe entirely within it.

F, is a screw screwing into the secondary toe close to the end which is next the point of the main toe, said screw passing through the main toe.

c, is a small spring placed ina recess in the main toe at the back of the secondary toe and on the saine side of the pivot Y), as

16,171, dated December 9, 1856.

the set screw F, said spring exerting a pressure against the secondary toe, which tends to throw the long portion thereof, which is on the other side of the pivot Z), into the recess a.

CZ, is an arc-formed catch piece attached to the long portion of the secondary toe and working through a slot in the main toe.

c, is a sliding bolt working through a portion of the main toe below thebottom or back of the recess a, and having a spring f, applied to push it outward from the toe and into a notch in the catch piece cl. One end of the bolt c, protrudes through the rear portion of the toe.

G, is a piece of metal with a curved face n, ni", fitted to slide in a recess g, in the face ofthe lifter, said recess being opposite the recess a, in the toe. This sliding piece G, is furnished on each side with a guide pin z', see Fig. 2, to work in an arched slot p, made through the lifter from each side of the recess g, and it is connected with a screw h, which passes through the back part of the lifter and is fitted with a nut j, which is confined to the lifter by a plate 7c, in such a manner as not to prevent it turning freely. This nut is furnished with cogs on its periphery gearing with a pinion Z, on a small spindle m, which turns in bearings on the top of the lifter. m, the pinion Z, is caused to turn the nut, which, operating on the screw, moves the sliding piece Gr, back or forward, in the recess g. Fig. 1, shows t-he sliding piece Gr, at the extreme back of the notch and Fig. 2 shows it in its mostforward position, the pins z', being at the extreme front end of the slots 77.

The operation is as follows: Before the main toe D, commences to rise to act upon the lifter, the secondary toe I, is entirely or almost entirely within the recess. This condition is shown in Fig. 1, where the lowest posit-ion of the toe is shown in red outline. As the main toe rises, its upper face acts upon the under face of the lifter, in the usual manner, and thus the valve is lifted, but during this action of the toe on the lifter to lift the valve, the point of the screw f, which prot-rudes some distance through the upper face of the secondary toe and stands above the face of the main toe, by being brought into contact with the face of the lifter, causes the short portion of the secondary toe to be depressed relatively to Byturning the spindles the main toe and the long end of the secondary toe to be elevated relatively thereto, as shown in black outline in Fig. Q. When this is elevated to its full height, the catch piece d, which has been moving with the secondary toe, is caught by the spring bolt e, which locks it and holds up the sec ondary toe, whose position is now close under the bottom rounded edge n, of the face of the piece G, belonging to the lifter and as its (the secondary toes) face is in the form of an arc described from the center of the rockshaft G, or nearly so, it continues to hold 'up the lifter until its point s, passes the rounded edge nt, after which the lifter is gently lowered to close the valve, by the point s, working up the face n, n2, of the piece G. After the descent of the lifter terminates, the beveled rear end of the spring bolt e, that protrudes from the main toe, in passing the edge ai?, of the piece is forced inward toward the point of the main toe far enough to liberate the catch (Z, and unlock the secondary toe, which is then drawn into the main toe, by the action of the spring c, so as not to interfere with the lifting of the valve by the main toe. By

moving the piece G, farther forward the lifter is caused to be held up longer and consequently the steam is admitted during a greater portion of the stroke of the piston, or by moving the piece G, farther back, a contrary effect, is of course produced. rI his change of position may be effected at any time while the engine is in motion by turning the spindle m. By screwing the screw F, to such a position that its point does not protrude through the face ofthe secondary toe, the secondary toe becomes inoperative,

that is to say, it is never lifted out of the recess a, and consequently the main toe and lifter operate in the same manner as the simple toe and lifter heretofore used.

In constructing my invention, the main toe must be set to such a position on the rockshaft, or the driving eccentric or its equivalent be so adjusted that the main toe act-ing alone without the secondary toe, will cut off the steam at the earliest point in the stroke that will ever be required, say, for instance, half-stroke, and the cavity g, in the lifter and the sliding piece G, so constructed that when the sliding piece is at the eX- treme back of the cavity, the point s of the secondary toe will pass the point s, almost as soon as the main toe begins to descend, and that when the sliding piece is in its most forward position, the secondary toe will hold the valve open nearly to the end of the stroke of the piston.

The same mechanism which I have described may be applied to the toe and lifter to operate the eduction valve, by which means the said valve may be left wide open till very near the end of the stroke of the piston and then allowed to close quickly but easily on its seat.

W'hat I claim as my invention and desire to secure by Letters Patent, is

The secondary toe I, applied to the main toe G, and operating substantially as herein described, in connection with a sliding piece G, or its equivalent, fitted to the lifter E, for the purpose set forth.

ALFRED S. BEEBE.

Witnesses JAMES F. BUCKLEY,

J. W. CooMRs.

Images