US444699A - Island - Google Patents

Description

(No Model.)

N. T. GREENE. SAFETY VALVE GEAR POR STEAM ENGINES. No. 444,699.

Patented Jan. l, .1%91.,

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NOBLE T. GREENE, OF PROVIDENCE, RHODE ISLAND.

SAFETY VALVE-GEAR FOR STEAM-ENGINES.

SPECIFICATION forming part of Letters Patent No. 444,699, dated January 13, 1891.

Application filed October 17, 1890. Serial No. 368,458. (No model.)

To @ZZ whom, it may concern:

Be it known that I, NOBLE T. GREENE, a citizen of the United States, residing at Provi-` dence, in the county of Providence and State of Rhode Island, have invented certain new and useful Improvements in Safety Valve- Gear for Steam-Engines; and I do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same, reference being had to the accompanying drawings, and to letters of reference marked thereon, which form a part of this specification.

My invention illustrated herewith is applicable to automatic cut-off steam-engines provided with detachable valve-gear having self-closing steam-valves. The device is, however, more particularly adapted to be employed in cut-offengines provided with governor controlled vertically -moving tappets, examples of which have been patented to me by the following United States patents: No. 12,507, of March 13, 1855, No.384,146, of Septeinber 4, 1888, and No. 425,219, April 8, 1890. The object I have in view is to render such engines safe from injury in case the governorbelt breaks, or, in other words, in the event of the sudden stoppage of the governor from any cause the device forming the subject of my present invention instantly comes into action, thereby automatically withdrawing the tappets from the toes of the steam-valve lcvers, the valves themselves at the same time closing the steam-ports com municating with the cylinder.

My invention consists, essentially, in the combination, with a mounted reciprocating' tappet-carrying bar or slide and mounted toecarrying valve-operating levers arranged to engage said tappets, of a mounted governor actuated and controlled gage-bar provided with means for changingthe relation or position of the tappets to the toes of the said valve-levers, all as will be more fully hereinafter set forth and claimed.

In the accompanying sheet of drawings, Figure 1 is a side elevation of a steam-engine provided with my imliirovements, viewed from the back of the engine. Fig. 2 is an enlarged side elevation, in partial section, showing a Figs. 2 and 4.)

portion of the engine, the several parts being in a normal position, as in operation.. Fig. 3 is also a side View, the relation of the parts corresponding to a depressed position of the governor-balls, as when the engine is not in operation. Fig. 4 is an enlarged transverse sectional view taken on line :r oc of Fig. 2, and Fig. 5 is a partial side view showing a bracket or stop for limiting the endwise movement of the bar when disconnected from the governor.

The following is a more detailed description of the invention and the manner of its operation.

a, referring to the drawings, indicates an engine fly-ball belt-driven governor of ordinary construction, the same having a central rod or shaft sZ arranged to move in a vertical direction in unison with the arc movement of the balls. (See dotted lines, Fio, 2.) rihe rod s2 is provided with counter-weights tu and a pair of collars n2. The adjacent faces of the latter are well rounded and engage an arm 7c of a pivotally-rnounted angle-lever.` The other (and preferablylonger) arm 7.o of the lever is bent or offset and provided with a pin k2, to which is jointed a rod n, which in turn is jointed at f2 to the horizontally-mounted tappet-support-ing or gage bar b. This bar is provided with two dogs f, adjustably secured thereto by set-screws m. The lower faces of the dogs are inclined or beveled and rest each upon a Iianged Wheel h, loosely mounted upon a stud or pin t. (See By this means it is obvious that any variation in the position of the governor-balls due to a change in load, dsc., produces a corresponding change in the position of the rods s?, and likewise an endwise 1nove ment of the bar o; but as the latter is supported by the inclined surfaces of the dogs resting upon the wheels 7L it follows that the bar will also at the same time change its position in a vertical plane.

The drawings, Figs. 1 and 2, represent a steam-en gin e having a detach able valve-gear, substantially as set forth in the patents here inbefore referred to. The valve stems or rods o connect with and operate the steam-valves o to uncover the steam-ports To the rear end of the valve-rods are secured rocking le- IOO vers carrying toes t2, the lower ends of which are beveled and adapted and arranged to engage the oppositely-inclined upper ends of the vertically-movable steel tappets t, mounted in a sliding bar or carrier d, which reciprocates back and forth longitudinally of the cylinder c in suitable guides by means of the eccentric e and its rod c', jointed to a pin e3, secured to the bar. The tappctst extend through the lower side of the sliding bar and rest upon the upper face of the supporting or gage bar l).

Now, from the foregoingdescription itis apparent that an engine having its governor c driven by a belt b2 will causo the rod s2 to move vertically up or down in unison with any change in diameter of the circle plane described by the governor-balls, and as the angle-lever le is connected with and actuated by the said rod s2 such movement'J is transferred to the gage-bar through the medium of the connection n, jointed both to said bar and the other arm t" of the angle-lever. At the same time the sliding bar in reciprocating back and forth by the eccentric causes the tappets to alternately engage the toes t2 of the rocking levers and uncover the steamports, thereby admitting live-steam into the cylinderand against the piston. The amount of steam-opening or point of cut-oif is determined by the height of the tappets above the face of the sliding bar, an increased height causing them to engage the toes for a longer period, thereby producing a longer cut-off, the toes then moving through a greater arc before the tappets actually become disengaged therefrom. Upon such disengagement 4a weight or other device, as common, acts to instantly close the valve, the valve-levers resuming the normal position, substantially as indicated by Fig. 3. By this it will be seen that for a given cut-off the versed sine of the corres pondin g arc passed th rou gh by the valve-lever will be just equal to theportion of the tappet (measured vertically) in engagement with the toe or lever, or, in other words,the tappet will be only in actual engagement with the toe, while the former is traveling horizontally a distance equal to the sine of the arc through which the lever moves. This arc is lnade automatically variable, in accordance with the load upon the engine, by means of the governor-actuated gage-bar b, which supports the tappets and determines their relative height above the sliding bar d by the inclined dogs f, secured to the gage-bar` These two dogs resting upon the loose wheels 77, also operate to maintain the bar Z) horizontally. As drawn, a flexible connection Z, passingover a wheel 7L', is secured to the rear end of the gage-bar, the same having counter-weights u; adapted to assist in carrying the bar endwise. It desired, a stop n, Figs. l and 5, may be employed to cheek the downward movement of the weights. The free end of the connection n maybe extended to form a handle by which it can be readily unhooked from the pin k2 of the angle-lever, when desired. Now in case the governor-belt h2 breaks or the governor stops from any cause while the engine is running, then the weights w, ttc., instantly act to assist in forcing the gage-bar rearwardly to its limit, or substantially as indicated by Fig. 3, thereby at the saine time lowering the bar onto the wheels h, the tappets simultaneously dropping in unison with the bar l), so that any further movement of the sliding bar d, although carrying the tappets past the now stationary valve-levers, will be inoperative.

I claim as my invention"- l. In an automatic cut-off steam-engine, the combination of mounted steam-valve, operating rocking levers provided with toes, a reciprocating sliding bar, loosely-mounted tappets carried by the sliding bar and adapted to intermittingly engage said toes, and governor actuated and controlled gage-bar having said tappets resting thereon provided with inclinedbearingorsupporting surfaces,where by an endwise movement of the gage-bar imparts a vertical movement to the tappets, substantially as hereinbefore set forth, and for the purpose specified.

2. The combination,in an automatic detachable valve-gear having automatically-closing steam-valves, of a mounted and actuated sliding bar carrying ta-ppets arranged and adapted to engage the valve mechanism to uncover the steam-ports. and a governoractuated horizontally-mounted gage-bar provided with inclined surfaces for controlling the vertical movement of the tappets, substantially as hereinbefore set forth.

3. The combination, with a horizontallymounted reciprocating sliding bar, tappet-s vertically mounted therein,and rocking valvelevers provided with toes adapted to engage and be actuated by said tappets, of a horizontally-mounted counterweighted governor actuated and controlled gage-bar havin g said tappets resting thereon, dogs provided with inclined faces adjustably secured to the gagebar, and wheels supporting the gage-bar by the engagement of said inclined faces therewith, substantially as shown and hereinbefore described.

In testimony whereof I have affixed my signature in presence of two witnesses.

NOBLE T. GREENE. Witnesses:

CHARLES HANNIGAN, GEO. l-I. REMINGTON.

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