US320895A - Valve-motion - Google Patents

Description

3 SheetsSheet 1. G. S. STRONG. VALVE MOTION.

(No Model.)

No. 320,895. Patented June 23, 1885.

m Q Ow N4 PETERS: Pholo-Ulfiographar, Washington. D. C.

(No Model.) 3 SheetsSheet 2.

G. S. STRONG.

VALVE MOTION. No. 320,895. Patented June 23, 1885.

(No Model.) 7 3 Sheets-Sheet 3.

G. S. STRONG.

VALVE MOTION. No. 320,895. Patented June 23, 1885.

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I UNITED STATES PATENT OFF CE.

GEORGE S. STRONG, OF PHILADELPHIA, PENNSYLVANIA.

VALVE-=MOTION.

SPECIFICATION forming part of Letters Patent No. 320,895, dated June 23, 1885.

Application filed April 3, 1885. (No model.)

To 00% whom, it may concern.-

Be it known that I, GEORGE S. STRONG, a

citizen of the United States, residing in Phila delphia, Pennsylvania, have invented certain Improvements in Valve-Motions for Steam- Engines, of which the following is a specification.

My invention consists of mechanism described hereinafter, by which the valve of a steam-engine may be operated from the crank shaft or axle and connecting-rod, the movement obtained being essentially the same as that obtained by the devices which form the subj ects of my Patents Nos. 304, 970 and 304,972, of September 9, 1884, and No. 315,972, of April 14, 1885.

In the accompanying drawings, Figure l is a side view of my improved valve-gear applied to a locomotive-engine; Fig. 2, a plan view; Fig. 3, a perspective view of thevalvegear; Fig. 4, a general diagram .illustrating the action of my improved valve-gear; Figs. 5 and 6, diagrams illustrating the action of parts of the valve-gear; Fig. 7, a view of my improved valvegear in its simplest form, and Fig. 8 a modified form of the gear.

Referring in the first instance to Figs. 1, 2,

and 3, WV is the cylinder of a locomotive-engine, andV V the valve-lifter chests, 0 being the rock-shafts for the lifters, which are attached to the valve-rods B B. In the present instance the valves are what are termed gridiron-valves, as shown in the diagram, Fig. 4.

A is the connecting-rod of the engine, secured to the usual cross-head, guided in ways w, projecting from the cylinder WV. B isthe steam-valve rod, and B the exhaust-valve rod.

To simplify the explanation of the parts, I will describe the steamvalve-operating mechanism, as it is duplicated in the exhaust-valve mechanism, as shown hereinafter.

D is a fixed segment made in the arc of a circle, and secured to any available fixed part of the engine, the dotted line 00 representing the central line of the engine-that is, a line passing through the center of the cylinder and that of the crank-shaft. It is also the central line of the connecting-rod when the crank is either at its rear or front dead-center.

In Fig. 1 the crank-pin is supposed to be at the rear dead-center.

To the segment D is fitted ablock, E,which is adjusted thereon. One-end of a link, F, is secured to this block E by a pin, e, the opposite end of the link being connected by apin, f, to a lever, H, which has a short arm, h, connected by a pin, d, to one end of a rod, G, the opposite end of the latter being connected by a pin, 1), to the valve-rod B, which is also connected to the upper end of a rocking link, I, by a pin, 1', the lower end of the latter being hinged by apin, g, to any available fixed part of the engine. This rocking link supports the end of the valve-rod B and link G when the two are connected together.

All the above-described features are shown and specified in my Patent No. 304,970, of September 9, 1884, and it is the combination of these features with the following which I wish to secure by Letters Patent. A lever, J, is attached to the connecting-rod A by a pin, m, the other end of the lever being attached to a link, K, by a pin, k. This link K is pivoted to a fixed part of the engine on the same side of the connectingrod as the rest of the valve-gear. The rod H is connected to the lever J by a pin, Z, in the present instance about midway between the pins m and 7c. The object of the lever J and link K, constructed and combined as described, is to overcome the error that would ensue if the lever H were pivoted directly to the connecting-rod A, as it is necessary to have an equal opening of the ports at bothv ends of the cylinder; hence by pivoting the lever J' to vthe connecting-rod A at m, and the rod H to the lever at Z, the pin 1 will describe the irregular oval 1?, which extends about double the dis tance below the line at as it does above, thus compensating for the error. I

Ihave described above only thesteam-valve operating mechanisn1;but the same description will apply to the exhaust-valve-operating mechanism, as it is identical both in construction and operation, and I have lettered the parts of the exhaust apparatus prime.

Both mechanisms can be operated independently of each other by means of the rods jj, which connect the blocks E E with the operating-stand in the cab of the engine.

Inexplaining the operation of the abovedesoribed valve-motion, reference may be had to Figs. 1 and 4, the line a: in the diagram, Fig. 4, corresponding with the line as in Fig. 1.

The parts as illustrated in Fig. 1 are in the position shown when the crank-pin a is at its rear dead-centerthat is, the pin a is at its nearest point to the cylinder, the piston being at the rear end of the same, the center line of the rods shown by full line and marked with the same reference-letters as Fig. 1.

The circle M indicates the path of the center of the crank-pin a, the oval N the path of the pin m, the irregular oval P the path of the pin Z. The block E is midway between the two extreme adj usting-points-that is to say, mid-gear.

\Vhen the crank-pin a has been moved in the direction of its arrow in the diagram until it is at the outward dead-centerthat is, at number 24-the several pins m, Z, and It will also be at the points numbered 24 in theirseveral paths. The pin f will be in the same position when the crank-pin is at its front deadcenter, 24, as when at its rear dead-center, 1; but the pin d will have a movement from 1 in the {direction of its arrow to 24, as shown in the enlarged diagram, Fig. 5, being onehalf of an irregular oval, the pin f moving to the point number 12 and back again to 24, when the block E is at mid-gear. (See Fig.6.)

WVhen the crank-pin a is at 24,the piston of the engine will be at its extreme forward limit. In returning, the crank-pin a travels from the front dead-center to the rear dead-center, 48 or 1, in the direction of its arrow, the pins or and Z traveling the upper half of the path to 48 or 1; but the pin 7.; travels in the same path going fromthe front to the rear dead-center as in going from the rear to the front dead-center. The pin f travels from the point 24 to the extreme point 36, Fig. 6, back again to 48 or 1, the pin b traveling from 24 to 48, being the remaining half of the irregular oval,as described above, and indicated by the dark section, Fig. 5. It will now be seen that a compound movement is imparted to the lever Hnamely, first, a vibrating movement on its fulcrumpin f, and, second, a movement of the lever by which, under the control of the rod F, the fulcrum-pin is caused to traverse in the arc of the circle. To this second movement is due the throw of the valve, the extent and direction of the throw being determined by the adjustment of the block 011 the segment. To the first movement-that is, to the vibration of thelever on its fulcrumpinis due the lap-lead and cut-off of the valve.

I have shown both in Fig. 1 and the diagram, Fig. 4, the block E in its mid-gear position,(marked z.) The movement of the crankpin when the block E is in this position will not affect the fulcrum-pin f, and consequently will not open the valve-ports; but thelever H will have its vibrating movement on the fulcrum-pin, and the pin d will describe the ir regular oval a, (shown by dark section,Fig. 5,) which will not affect the opening of the valves. By moving the block E from the mid-gear position z to the full-throw position .2, the pin f will travel in the are of the circle w, Fig. 6, and the pin (Z will travel in the irregular path a, Fig. 5, the ports of the engine being full open, and having the required lap-lead and cutoff. Should the block E be adjusted to the position 2 the travel of the fulcrum-pin will be in the arc of the circle 10 and the motion of the valve reversed. The pin (1 will travel in the irregular path n Fig. 5.

Turning nowto Fig. 8, which represents the valve-motion without the lap-lead and cutoff gear, the block E being raised on the segment D, in this instance the arm h of the lever H is dispensed with, and the rod G connected directly to the pin f. This gear is intended to be used on engines in which the lead of the valve is obtained by mechanism outside of the valve-operating mechanism. WVhen the block E is at mid-gear z, there will be no movement whatever of the valve-rod, the pin f traversing in the arc w,- but when the block has been adjusted to its lowest point, z, the pin will traverse in the are 10 and the valve will have its full throw. Should the block be adjusted to the position z the pin f will traverse in the arc w and the motion of the valve will be reversed.

' Referring to Fig. 7, which represents the valve-motion in its simplest form, the rod F is secured to a position on any fixed part of the engine, the valve-rod B in this instance sliding in a bearing in this fixed projection. In this case the engine is intended to run forward, and is regulated by the ordinary throttle-valve. In most cases itis desirable to make the valve-motion, as shown in Fig. 1, and as illustrated in the diagram, Fig. 4, so that the two movements of the valve may be obtained, one being the ordinary throw of the valve, the other the lap-lead and cutoff of the valve.

It will be observed that owing to the combination, with the devices of my former patents, of the lever J, and of the pivoted link K on the same side of the connecting-rod as the other levers, none of the valve-gear lies below the connecting-ro'da feature of importance, especially in locomotives, for in the latterit is desirable to have the operating-levers as far from the track as practicable, so as to avoid the throwing of dirt up into the working parts, and also to avoid possible obstructions along the track striking such levers as might lie below the connecting-rods.

In other forms of engines the construction described takes all the valve-gear away from the bed-plate or condenser and makes the structure more compact.

I have shown in the diagram, Fig. 4, my valve-motion as applied to a gridiron-valve; but it will be "understood that the motion can be applied to different forms of valves as well.

I claim as my invention 1. The combination, in valve-gear for steamengines, of the following elements, namely: first, the pivoted link F, having a fulcrum-pin, f second, a connecting-rod, A, lever J, pivoted thereto and to a pivoted link, K, on the same side of the connecting-rod as the rest of the valve-gear, a rod, H, pivoted to the lever J and to the link F by the fulcrum-pin f,- third, a link, G, connected also to the fulcrum- 5 pin f and to the valve-rod B, all substantially as set forth.

2. The combination, in valve-gear for steamengines, of the following elements, namely: first, a fixed segment, D, and a block, E, ad-

IO justable thereon; second, a lever or link, H,

and connecting-rod A, lever J, and link K, pivoted on the same side of the connectingrod as the rest of the valve-gear, forimparting the within-described compound movement to 15 the lever H; and, third, a link, F, connecting the adjustable block to the lever H by a pin, f, to which lever is also connected the valve rod, substantially as set forth.

3. The combination, in valve-gear for steam- GEORGE S. STRONG.

Witnesses:

HARRY SMITH, HENRY HoWsoN.

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