US46020A - Improvement in cut-offs for steam-engines - Google Patents

Description

UNITED STATES PATENT OFFICE.

J. H. PAINE, OF HARTFORD, CONNECTICUT.

IMPROVEMENT IN CUT-OFFS FOR STEAM-ENGINES.

Specification forming part of Letters Patent No. 46.020, dated January 24, 1855.

To all whom it may concern Beit known that I, J. H. PAINE, ot' Hartford, in the county ot' Hartford and State of Connecticut, have invented a new and Improved Cut-ott; and I do hereby declare that the t'ollowingis a full,clear, and exactdescription thereof, which will enable others skilled in the art to make and use the same, reference being had to the accompanying drawings, forming part ot' this specification, in which- Figure l is a sectional side elevation of this invention. Fig. 2 is a sectional plan of the same. Fig. 3 is a detached sectional view of the valve-rod in a larger scale than the previous figures.

Similar letters of reference indicate like parts.

This invention consists in the employment or use of a spiral cam applied in combination with the governor and with the main valve and cut-ott' valve of a steam-engine in such a manner that by the action of the cam on the rod of the cut-oftl valve the steam is cut off instantaneously, (or nearly so,) and, the wire drawing ot' the steam is avoided, and, furthermore7 the cam being in action for a short space. of time, leaves the governor free during the largest part of the stroke.

It consists, further, in the application ot' a latch and sliding pin, in combination with the rods of the main valve and of the cut-off valve and with a suitable cam in such a manner that by the action of the latch the main and cut-off valves are locked open, leaving no liability to close the ports until the proper time arrives, and by the action ot' the cam and pin the two valves are disconnected instantaneously, allowing them to move in the same or in opposite directions as occasion may require.

A represents a steam-cylinder, which is provided with two steam-chests, B, one at each end, and each steam-chest contains a separate slide-valve, C, and cut-oft' valve D.

One end of the cylinder only is shown in the drawings; but the operation ot' my cut-ott' will be readily understood from the following description, since the valves at that end ofthe cylinder which is is not shown are operated by the same cam precisely in the same inanner as those which are represented.

The cylinder takes steam through the port a in the valve-seat and through a corresponding channel, uit, in the main valve C, and it exhausts through the port b and corresponding cavity, bit, in the face ot' said valve, and

the channel ai is alternately closed and opened at the proper intervals by the cut-oft' valve D.

The stem c ot' the main valve C is hollow and iirmly secured in a standard, E, which rises from a slide, F, to which a reciprocating motion is im parted by an eccentric, Gr, mounted on the spindle H ofthe governor I, or by any other suitable means.

The cut-oft' valve D is iittcd steam-tight on the back ofthe main valve C, and itis provided with a channel, c', which can be brought to register with the channel a* in the main valve or not, as circumstances may require. It' both channels register wholly or partially with the port a, steam passes into the cylinder; but it one of the two channels or both do not register with said port steam is cut oft'.

The stem d of the cut-oft valve D extends through the hollow stem c ot1 the main valve, and the two are locked together by a latch, e, which is hinged to the top of the standard E and drops in a notch,f, in the valve-stem d. The position of the latch and notch in relation to each other is such that when by their action the two valve-stems are locked together, the channel at in the main valve registers with the channel a in the cutoff valve, or, in other words, the two valves are locked open and are not allowed to close before the specied time.

In order to release the latch automatically at the proper instant, a pin, g, is titted into the end of the valve-stem, and a tlat spring, h, secured to the front end otl this pin, bears with its loose end on an inclined piane, i, under and behind the notch j', as shown in Fig. 3 of the drawings.

Itl by some pressure exerted on its head the pin g is driven back in its socket, the spring h ascends the inclined plane i, and the `latch is raised so as to clear the notch j', and when the pressure ceases the spring li, carries the pin back to its original position. This object is effected automatically at the desired instant by a cam, J, which is arranged on the spindle H of the governor, so that it rises and falls freely on t-he same, but is compelled to rotate with it. Said cam is formed by a spiral iiange, which acts on the pin g during 'different parts of the stroke, according to the higher or lower position of said cam on the spindle of the governor. If the cam is moved down on the spindle as far as it will go7 steam is admitted during the full stroke of the piston 5 but if the cam is moved up to its central position steam is out o' at half-stroke, and if the cam is raised as high as it will go no steam at all is allowed to pass into the cylinder7 or steam is cut off at full stroke.

It will be readily understood what the effect ofthe cam will be in its intermediate positions, and if the cam is connected to the governor the position of the cut-oft' valve will be regulated automatically according to the requisite speed of the engine. The connection of the cam and governor may be effected in a simple manner, and the action ot the cam is such that it leaves the cam free during the largest part ot' its revolution, and the friction between the valves is nearly all removed, as the stem of the out-o'valve is held in contact with the cam only until the port is closed, and is then allowed to travel with the main valve. The

sensitiveness of the governor is thereby in creased and a more uniform speed of the engine effected than with governors and cut-offs 0f the ordinary construction.

An adjustable stop, j, is secured in the outer end of the steam-chest, which serves to retain the eut-oft' valve stationary. in the proper position while the main valve traverses under it. rlhis stop is so adjusted that the port in the cut-oft' valve will register with that in the main valve until the action of the cam J on the pin g commences. l

I claim as new and desire to secure by Letters Patent- 1. The spiral cam J, applied in combination with the governor and with the main valve C and cutoff valve B, substantially as and for the purpose set forth.

2. The sliding pin g and hinged latch e, in combination with the valves C D and cam J, constructed and operating substantially as and for the purpose described. A

J. H. PAlNE.

Witnesses Ron'r. W. HAMILTON, E. J. MURPHY.

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