US92648A - Improvement in direct-acting engine valve-gear - Google Patents

Description

n'itrd tatra parte (amm.

Letters Patent No. 92,648, [lated July 13, 1869; antetlatecl July 3, 1869.

` IMPROVEMENT IN DIRECT-ACTING ENG-IE VALVE-GEAR.

The Schedule referred to in these Letters Patent and making part; of the same.

To all whom it may concern Be it known that I, JOHN B. ROOT, of the city, county, and State of New York, have invented a new and useful Improvement in Valve-Gear of Direct- Acting Engines, of which the following is a full, clear, and exact description, reference being had to the accompanying drawing, forming part ot' this specification, in which Figure 1 represents a side elevation of an enginecylnder, with my improved valve-gear applied thereto, an

Figure 2, a longitudinal section of the same, with the engine-piston as in position, or nearly so, for actuating or'starting the valves which serve to control it.

Similar letters of reference indicate corresponding parts. Y

This, my improvement in valve-gear, is applicable to direct-acting engines oi' various kinds, includingvv steam-engines, pumps, and blowers; but it will suflice here to describe it as applied to a direct-acting steamengine.

My invention consists in the combination and arrangement ot' disk or piston-valves, that control the ports at the opposite ends of the cylinder, said valves being connected, in a balanced manner, by a rocking beam, having a shifting or movable fulcrum, operated by the 'engine-piston, as it approaches the end of its respective strokes, through a sliding bai', shifting said fulcrum, and whereby the balancing-character ot' the valves isdestroyed, by increasing the beam-leverage of the one valve, as compared to the other, and so causing the valves, under the pressure of steam or fluid, to rapidly change their positions, relatively to the ports, for the purpose of reversing the stroke of the engine-piston.

Referring to the accompanying drawing- Ir represents the cylinder of a direct-acting engine, anc

B, the piston reciprocating therein.

G is a steam-chamber or space, supplied with steam from the boiler by a pipe, a, and

D, an exhaust-chamber, having an outlet-pipe, b.

E E' are cylindrical valve-chambers, containing piston-valves G G', titiel to play in a` close but free manner therein.

These valve-chambers E E are connected, by upper` passages c e', with the steam-space C, and by lower passages l el', with the exhaust-chamber D als'o, by ports or passages e e', with the cylinder A, at its opposite ends.

'Ihe valves G G' are, as it were, independent of each other, but connected to work in unison, by means of rods ff, working through stuing-boxes g y', and resting on, or otherwise being suitably attached to the. opposite ends of a rocking beam, H, that works on a fulcrum, I.

This fulcrumit is necessary, should be of a movable or shifting character, in order that it may'be thrown destroys to opposite sidesy of the centre, orpoint which establishes a balanced action to the valves. 4

Thus, said fnlcrum may be a lcverworking in bear-- ings h h', and, when the valves are of eqlal area and weight, and beam of uniform shape, the same may be disposed so that when standing vertical, or thereabout, the beam H rests at its centre upon the fulcrum I.

The shaft i of said fulcrum carries a toe or arm, 7.',

arranged to gear with a sliding bar, J, that has con-` nected with it,.at opposite ends, rods m an', which project, through stung-boxes, into the intelgior of'the cylinder A, at its ends.

From this description, it will be seen that when the beam H rests at its centre on the fnlcrnm I, the valves G G balance each other, the pressure of steam on their upper surfaces vbeing alike on both valves. ButY on steam being admitted to throw the piston B to the right or left, and which may be done to start the engine, by sliding by hand, to the right or left, the bar J, said piston, as it approaches the end of its stroke, strikes the one -rod m or on', and so throws the fulcrum I to the opposite side of the beam-centre, which the equilibrium of the valves, by increasing the beam-leverage of the one valve as compared to the other, so that the pressure of live steam on the valve having the longest beam-leverage depresses said valve, and causes the opposite valve-to be correspondingly raised. ports ee with Vthe steam and exhaust-chambers C and D, and so changes the direction in travel of the piston. Alike rapid and automatic action of the valves occurs on the piston reaching the other end of its stroke, by its striking the rod on or m', so as to shift the fulcrum I to the opposite side of the beam-centre, and again reverse the position of the valves, relatively to the ports, or passages controlled by them.

Thus, or by means of the shifting iulcrum, a single pair of valves suffices, instead of two sets, in which the one is operated mechanically by the piston, and the other thrown by the steam, as the same is admitted to them alternately, by the first pair or set of valves. In the present arrangement, the valves G G are thrown by the steam, but not until the fulcrum that secures their balance has been mechanically shifted by the engine.

`It is desirable that thevalve-cylinders E E shouldA be sufficiently extended below the exhaust-passages d el to hold or contain a'certain amount-of spent steam when the valves are down, so as to act as a cushion to said valves, and to secure to them an equilibrium, as regards pressure on their surfaces, and whereby they are made to play easier on theshifting of the fulcrum. y

It also is desirable to make the throw of' the valvesl adjustable and variable, as regards their action, in

point of time, relatively to the' piston. This may be done by making the rods 'm m adjustable, by screwthread cut. on them, in or through the ends of the This reverses the communication of the sliding bar J, sq as to cause said rods to project more or less within the cylinder, and thereby be struck earlier or later in the pistous stroke. VVbeu thus set, the rods m m may be secured by lock-nuts n n.

XVlxat is here claimed, and desired to be secured by Letters Patent, is

The arrangement and combination of the sliding bar J, lever I, and beams H, with the valves G and G', for operating said valves by ton B, substantially as set forth Witnesses:

A. Las CLERC, A. KINNIER.

the travel of the pis- JOHN B. ROOT.

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