US186584A - Improvement in steam-pump valve-gears - Google Patents

Description

UNITED STATES PATENT .GEFICE.

BENJAMIN s. LAWSON, OE NEW YORK, N. Y.,

IMPRCVEMENT `lN STEAM-PUMP VALVE-GEARSL Specification forming part ofLetters Patent No. 186,5134, dated January 23, 1877; application filed To allwhong t may concern: Y

Be it known that I, BENJAMTN S. LAWSON, ot' New York city, in the State of New York,

have invented certainnew and useful Improvements relating to Steam-Pumps, of which the following is a specification:

The pump is ofthe direct-actin g class, where the pump-piston and steam-piston are, practically, parts of the same reciprocating mass.

The improvements lie in the means for throw- Y .control the movement of the lever which' operated the valve.

I find the crank may be dispensed with, and

have devised means wherebyl obtain a prompt and reliable movement of the valve without any such incum brance. I have wrought out the invention with devices to insure that the valve will be thrown to the proper extent before the piston has moved far, in case the spring is insufficient to induce the proper extent of motion; and I have provided means for restraining the action of the spring, so as to prevent its acting beyond the proper limit in case it shall, as is usually the fact with a new spring, have more than the proper amount of force.

The accompanying drawing forms a part of this specification, and is a side elevation. The

pistons are to the left. The valve-lever is shown in the dotted line in the position to which it is thrown by the spring so `soon as the pump has passed the center. The strong line shows the position in which it is held a moment previous.

Referring to the drawing, A is the ifixed framing and cylinders. Bis the piston-rod, extending through from the steam-cylinder to the pump, the steam-cylinder being at the left. On the piston-rod B is keyed a part, B', which extends down, and is guided in a longitudinal slot in the framing A, and also extends up- December 23, 1876.

wardand carries a cam, P, formed as represented. lhis cam is incapable ot'auy motion but a direct reciproeation with the pistons.

` The valve-stem E is connected to the arm D3,

and reciprocatesV by the rocking of the lever, thereby working a valve, (shown in dotted lines,) which performs its usual functions. A

center or pivot bolt, b, is n xed in the side of the part B', to which are knuckled two levers. The lever H travels smoothly backward and forward, being guided on the framing A, and forms simply a support or shoe for a spring, I. A lever, J1 J2, is also knuckled on the pivot-bolt b, which is capable of a slight rocking motion. The long arm J1 is forced upward by the spring I. The short arm J 2 serves simply as a stop to prevent the other arm, J1, from being thrown too high. The arm J1 nds a smooth bearing against the under face of the lever D1 D2, being rounded (or, if preferred in any case, provided with a shoe) to accommodate the bearing to the changing angle of the lever against which it rocks.

As the part B' and its connections traverse alternately to the right and the left, the bearing of the lever J1 against the lever D1 Dz changes its position from end to end. As it approaches either end of its stroke, the corresponding end of the lever D1 D2 is pressed upward. The cam P restrains its motion, and

forbids any movement until the pistons have completed thir stroke. Then the side projection (which will be understood is on the end of the arm D1) is liberated by having passed beyond the end of the cam P; and the parts, being thus set free, are thrown by the force of the spring'I, acting through the arm J1, and the valve-stem E is movedto change the position of the steam-valve. In case the throw thus effected is not quite complete, as is indicated by the dotted lines in the figure, and

only a partial opening ofl the steam-valve is effected, the commencement of the motion of the pistons will bring the part p of the cam P into action, and thus carry the arm D1 up or down, as the case may be, to its full proper extent.

necessary in ordinary cases.

the cam P which holds the parts against be- In case the motion resulting from the action of the spring I should, instead of thus being too little, be in any case too much, and should tend to throw the parts too far, the contact of the arm J2 against the adjacent portion of the part H arrests the movement.

Various modifications may be made in the forms and proportions of' the parts without defeating the objects of the invention. Various refinements may be added- 21s, for example, a screw may be inserted through the arm J2, to adjust the point at which the rise of the arm J1 under a too forcible action of the spring I shall be arrested. A roller may be provided on the side projection on the arm D1, to form a rolling contact, rather than a sliding one, with the cam; but I do not believe an)T such That portion oi' ing thrown too early is designated p. It may be of the form represented, exactly parallel to the piston-rod, with a rounded corner; or it may be further rounded; or variously modied, solong as it holds the valve againstbeing thrown too early.

I claim as my inventionlhe spring I and cam P p, each traversed as specified, in combination with a rocking lever traversed and operated by the joint action of the'spring and cam, and with the lever J1 J2, connectedv valve-rod E, and the cylinders and pistons of a steam-pump, as and i'or the purposes herein specified.

In testimony whereof I have hereunto set' luy-hand this 20th day of December, 1876, in the presence of two subscribing witnesses.

BENJAMIN S. LAWSON.

Witnesses:

THOMAS D. SrETs'oN, GHAs. G. STETsoN.

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