US7987A - Adjustable cut-off - Google Patents

Description

s. H. GILMAN. STEAM REGULATOR AND GUT-OFR' No. 7,987. Patented Mar. 18, 1851.

SAML. H. GILMAN, OF CINCINNATI, OHIO.

ADJUSTABLE CUT-OFF.

. Specification of Letters Patent No. 7,987,dated March 18, 1851.

To all whom it may concern: l

Be it known that I, SAMUEL H. GILMAN of Cincinnati, Hamilton County, Ohio, have invented new anduseful Devices for Regulating the Admission of Steam to Steam- Engines; and 1 do hereby declare the following tobe a full, clear, and exact description thereof, reference being had to the annexed drawings, making part of this specification. j The principal objects of my improvements are let The application to a slide steam valve of an arrangement of cut off mechanism, actuated by the movement of thevalve rod, and having the periods of its out off action either subjectto the 1110 mentary control of the engineer or dependent on the movement of the steam governor thus constituting the cut off action a means of regulation of the rate of the engine.

2d In the devices wherebya portion ofthe out off apparatus is made operable as a throttle valve.

In the accompanying drawings Figure 1 is a vertical section parallel to the path of the slide valve. Fig. 2 is a vertical section through the puppet valve at right angles to the first named.

The same lettersrefer to like parts in the several figures.

valve (0) and (1)) (opening into one side of it) is the chamber of a balance puppet valve (d).

(e f f) are the usual ports. (9) the'slide valve rod is for a portion of its length (9) square'sided for purposes hereafter eX- plained. The steam passage (h) of the balance puppet valve (d) communicates (when the valve is lifted,) from the steam supply pipe to the slide valve chamber (a).

(j) is a lever by which the puppet valve is lifted. This lever is at its rear end pivoted to a rod (k) which being adjusted to it-s proper height by the-set screw (m), is secured thereto by the hand screw (Z) tapped within it, or by means of the same hand screw, the lever may be drawn entirely .out of reach of the lifting mechanism, and by this means the steam may be shut completely off and the apparatus be made in this way to perform the duty of a throttle valve. Upon the return of the rod (is), the set screw (m) indicates the proper position. The upward range of the lever (j) is determined by the set screw (11.). Between the plained.

(a) is the chamber of an ordinary slide lever and the valve rod (9) intervenes a bar (0) A stufling box (q) immediately beneath for purposes hereinafter eX- the intersection of the puppet valve lever and the slide valve rod, provides for the passage up and downof a rod (r), which being connected by lever or other means with the governor is depressed or elevated according to the speed of the engine, or being merely provided witha handle may be adjusted by the engineer in charge. To the summit of this rod is pivoted a swinging bar or tappet (t) the sweep of whose vibration is. limited. by pins (o) projecting from the tappet and a playing in slots i it) within (7*). The upper end of this tappet inhabits a vertical slot within the rod (g), which slot is so'formed that at theperiod of every half stroke of the slide valve, an end of the slot striking the tappet pushes it over to the opposite position. If the motion of sunk below the top of the valve rod, the bar (0) will again rest thereupon, and the puppet valve closing, the steam will be cut off at halfstroke; but if from the rod (1) being drawn downby the governor or otherwise, thetappet escapes the bar before the above period, the steam will be shut off at an earlier. period of the stroke and so forth. I j

To enable the period of cut off to be deferred to any point beyond the half stroke the following mechanlsm is provided: From each side of the bar (0) and immediately "cheeks (.9) attached to the top of the rod over the cheeks'(s) project lugs (p) whose under sides incline from the mid length of the lug in both directions upward so as to present an obtuse salient point whose base stretches in the direction of and equal to the stroke of the slide valve and whose height equals one half the vertical range of thetappet. are a pair of plates formed on their upper edges in two planes inclining downward toward each other, equal and parallel to those upon the bar. These plates, slide to and fro with the valve rodto which they are attached by pins working in vertical slots which permit of a play up and down equal to the height of their inclined planes. The checks (8) and plates to are so placed with respect to each other and the bar that when the rod (1') passes above the middle of its range, the checks (.9) bearing upward against the plates elevate the more salient portions of their top edges, above the level of the valve rod top and the height of these inclined planes being equal to the vertical range of the plates and their joint horizontal span to the sweep of the valve, the salient portions of the plates meeting as the valve rod (g) progressesthose of the lugs upon the bar, the latter is thereby held up, after the tappet has ceased to act.

This action is exhibited in the drawing as it would appear at half stroke of the piston with the plates elevated to the extent adequate to cut off the steam at three quarters stroke, that is when the slide valve has traversed one fourth of its return movement, and the apex (l) of the lugs (p) having reached the point (2) of the plates, at which they coincide with the top of the valve rod, the bar (0) returns to its restingplace on the top of the rail of the slide valve, and the puppet valve closes. Were the coinciding point of the plates half way between that in the instance here cited, and the center (3) of the notch, the steam would be cut off at seven eighths stroke and so forth.

The motion of the governor on the one hand and that of the out OK apparatus on range of the former will correspond to the range of cut offs deemed most desirable.

Having thus particularly described the nature of my improvements what I claim therein as my invention and for which I desire Letters Patent is- 1. The tappet (t) vibrated by the impact of projections upon the slide valve rod, and lifting thereby a puppet valve which admits steam to the slide valve chamber during periods varying with the height to which the tappet is placed by the elevation or depression of the sliding rod, or other object to which it is pivoted, said rod being raised or depressed by a motion derived from the governor or communicated to it in such other manner as may be deemed expedient.

2. I claim the mechanism substantially as described for prolongation of the admission of steam beyond the period at which it would be cut off by the tappet, to wit, the sliding plate (w), and the intervening bar (0) the former with a pair of receding inclined planes or edges, and the latter with an equal and parallel 'pair of salient planes which by sliding upon the former, hold up the pup pet valve after the tappet has ceased to act, fora period likewise depending upon the movement of the rod, which latter may be actuated as set forth in the former claim.

In testimony whereof, I have hereunto set my hand before two subscribing witnesses.

SAMUEL H. GILMAN,

Witnesses:

EDWARDA. KNIGHT, GEO. H. KNIGHT.

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