US320892A - strong - Google Patents

Description

(Nb Model.) 3 Sheets-Sheet 1. G. S. STRONG.

VALVE OPERATING MECHANISM.

N0. 3120;892. Patented June 23, 1885.

(No Model.) 3 Sheefis-Shet. 2. G. S. STRONG.

VALVE OPERATING MECHANISM.

Patented June23, 1885.

N. PETERS. PhutvLilhographu (No Model.) 3 SheetsSheet 3.

G. S.'STRONG.

VALVE OPERATING MECHANISM.

No. 320,892. Patented June 23, 1-885.

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CW Inventor george J Straw/ q M, /.\//%;%W W W N. PETERS, Phnloljlhcgnphar. wahing'ton. D.C.

VNITED STATES GEORGE S. STRONG, OF PHILADELPHIA, PENNSYLVANIA, ASSIGNOE TO JOHN T. MORRIS, TRUSTEE, OF SAME PLACE.

VALVE-OPERATING MECHANISM.

SPECIFICATION forming part of Letters Patent No. 320,892, dated June 23, 1885.

Application filed July 11, 1884. (No model.)

To all whom it may concern Be it known that I, GEORGE S. STRONG, a citizen of the United States, and residing in Philadelphia, Pennsylvania,have invented certain Improvements in Valve-Operating Mechanism for Steam-Engines, of which the following is a specification.

My invention consists of mechanism, described and claimed hereinafter, for imparting an advantageous differential movement to slide-valves, and especially to gridironvalves, of steam-engines.

In the accompanying drawings, Figure 1, Sheet 1, is a front view, partly in section, of my improved valve-operating mechanism; Fig. 2, a diagram illustrating the differential movement imparted by the device; Fig. 3, Sheet 2, a section on the line 1 2, Fig. 1, parts being in elevation, and Fig. 4 a diagram illustrating the valve-path.

A chest, A, for each valve is bolted to the main valve-chest, and through a stuffing-box, a, screwed into the bottom of the chest A, passes the valve-spindle B, the upper end of which is secured to a projection, b, on a bar, D, the latter terminating at its upper end in a piston, h, adapted to a small cylinder, E, which serves as an upper guide for the valvespindle.

A rock-shaft, G, passes through a projection, i, on the chest 'A, and on this shaft is an arm, M, the pin nof which is connected by a rod, H, to a pin, 12, passing through the bar D. On this rock-shaft G is a forked arm, N, carrying a pin, P, for receiving the end of the rod-an eccentric rod, for instance-through the medium of which the said arm and rockshaft are vibrated.

On referring to Fig. 1 it will be seen that the center a: of the rock-shaft G is at a distance from the line 1 2, drawn through the center of the valve-spindle and cylinder E.

The relation of the two arms N and M to each other is indicated by the dotted line t 15, passing through the center to of the pin 12 and the center of the roclcshaft, and the line '12, passing through the latter center and the center of the pin P of the arm N.

Assuming that a uniform vibrating motion is imparted to the arm N of the rock-shaft to the extent indicated by the lines o and y and the dotted segment, Fig. 1, the upward movement of the valve-spindle will be of a differ ential character, which can be best explained by reference to the diagram Fig. 2, in which the dotted line 2 2 is the central line of the valve-spindle, and x the center of the rockshaft, the dotted segment indicating the course of the center of the pin a of the arm M, and the points 7 and 6 indicating the extent of vibration of the said pins center.

During the movement of the said pin from 7 to 4.that is, more than half of the extent of its vibration-there will be the slight movement of the valve-spindle indicated by the distance between the horizontal lines 8 and 4 crossing the line 2 2, the distance of the line 5 from the line 3 showing the distance to which the valve spindle will be raised when the crank-pin has reached the point 5. While the said pin, however, moves from the point 5 to the point 6, nearly at right angles to the spindle, there will be a rapid rise of the valvespiudle from the horizontalline 5 to the horizontal line 6.

The path of the valve produced by the abovedescribed motion is illustrated in the diagram Fig. 4, from which it will be seen that the valve is kept in constant motion. During the lap this movement is very slight, and not enoughto afiect the correct opening of the ports or to cause perceptible friction or wear on the valve or valve-gear. The movement is sufficient, however, to prevent the valve from sticking to the seat, as is apt to be the case where the valve stops at a certain point in its path. This continued movement during the lap is caused by the passing of the arm M to the slight extent described beyond a line drawn through the centers of the pin 12 and shaft G. This differential movement for a gridiron-valveis the most advantageous which can be obtained without the aid of a cam,which is always objectionable, owing to the constant friction of one surface against the other.

I claim as my invention-- 1. The combination of the valve-spindle and the rock-shaft G with an arm, M, attached to the shaft and connected to the spindle at a point substantially as set forth, the said arm having a movement from a position at about right angles to the spindle to a point on or beyond a line drawn through the center of the shaft G and parallel with the said spindle.

2. The combination of the valve-spindle and the rock-shaft G with an al m, M, and a connecting-link, H, thesaidarni'Mhaving a movement Within the limits of the lines 6 7 past a line drawn through the center of the shaft G, and of the connection of the link with the IO spindle, substantially as set forth.

In testimony whereofI have signed my name to this specification in the presence of two subscribing witnesses.

GEO. S. STRONG. Witnesses:

JOHN M. CLAYTON, HARRY SMITH.

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