US788951A - Valve-gear. - Google Patents

Description

PATENTED MAY 2, 1905.

F. S. SCHMITH.

VALVE GEAR.

APPLIOATION FILED SEPT. 17I 1904.

3 SHEETS-SHEET 1 Gitane/1g fPATENTED MAY 2, 1905.

F. S. SGHMTH.

VALVE GEAR.

APPLIUATION FILED SEPT. 17, 1904.

3 SHEETS-SHEET 2.

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Wits/mossa No. 788,951. I l1911T11111E11 MAY 2, 1905.

F. S. SGHMITH.

VALVE GEAR.

APPLICATION FILED SEPT. 17, 1904.

' 3 SHEETS-SHEET a.

Patented May 2, 1905.

erica.'

FRANK S. SOHMITH, OF MILWAUKEE, WISCONSIN, ASSIGNOR OF ON E-HALF TO VACLAV SLADEK, OF MILIVAUKEE, WISCONSIN.

VALVE-GEAR.

SPECIFICATION forming part of Letters Patent No. 788,951, dated May 2, 1905.

Application Bied september 17, 1904. semi No. 224,808.

To rif/ZZ r11/tom, it www concern/f Be it known that I, FRANK S. SoHMITI-La citi- Zen of the United States, residing at Milwaukee, in the county ot' Milwaukee and State of Wisconsin, have invented new and useful Improvements in Valve-Gear, of which the following is a spe'citication.

This invention relates to steam-engines of that class having one inlet and one exhaust valve and provided with a cut-ofi' mechanism for the inlet-valve operated through suitable mechanism from the eccentric of the engine.

The object of the invention is to provide a valve mechanism for a steam-engine having few parts simple in construction and arrangement and having a novel cut-off mechanism for the inlet-valve, which may be quickly adjusted to vary the amount of steam admitted to the cylinder and which shall be noiseless in action and readily accessible for repairing or renewal of parts. i

In the accompanying drawings, Figure lis a side elevation of the engine-cylinder provided with the improved valve-gear, a portion being shown in section. Fig. 2 is a vertical longitudinal sectional view through the engine-cylinder, showing the inlet and outlet valves and the ports leading to and from the cylinder. Fig. 3 is a perspective view of a detail of the cam attached to the stem of the inlet-valve. Fig. 4 is a detail plan view showing the cams for operating the inlet-valve. Figs. 5, 6, 7, and 8 are diagrammatic views illustrating the operation of the invention.

Referring' particularly to Figs. 1 to 4, the numeral 1 indicates a steam-engine cylinder containing a reciprocating piston 2, attached to a piston-rod 3, operating the driving-shaft 4 (see Fig. 5) through medium of the connecting-rod 5. At each end of the cylinder are steam-inlet ports 6 and exhaust-ports 7, the inlet-ports 6 being in communication with passages 8, the admission of steam thereto being controlled by a rocking inlet-valve 9. The exhaust-ports 7 are similarly connected to passages 10, outlet therefrom being controlled by an exhaust-Valve 11. The numeral 12 indicates the steam-pipe, and 13 the exhaustpipe.`

Projecting from one side of the cylinder 1, to which it is rigidly attached, is a pivot 14, on which is journaled a rocking lever 15, the upper arm 16 of which is straight and has fastened thereto on its inner side an adjustable cam-plate 17, formed, preferably, of some nonmetallic or sound-deadening substance, such as lignum-vitae. The cam-plate 17, which consists of a thin strip having a knife-edge on its upper end, is fastened to the arm 16'by means of a bolt or screw 18, passing through a slot in the arm and into the cam. As thus arranged the cam may be moved a greater or lesser distance from the axis of the rocking lever 15, and thereby increase or decrease the movement of the inlet-valve 9 to admit more 65 or less steam to the cylinder.

Fixed to the stem 19 of the inlet-valve 9 is an arm 20, (shown in detail in Fig'. 3,) on the outer face of which projects a lixed cam-plate 21, which at certain times rests against the cam-plates 17. The valve-stem 19 has further attached to it a centrally-pivoted oscillating lever 22, to each end of which is pivoted a connecting-link 23, each link pivoted in turn to a vertical rod 24, adapted to move longitudinally within a cylindrical casing 25.

At a suitable distance above the lower end of each cylindrical casing 25 is a seat 26 for a weight 27, mounted loosely around the rod 24, the latter being headed below said weight 8O to lift it at the proper time. When the lever 22 is oscillated by means hereinafter described, the rods 24 are alternately raised and lowered. W'hen raised, the rods lift the weights 27 from their seats 26, and when lowered they return the weights to their seats `and pass freely through the opening therein to the bottom of the casing 25.

The lower end of the rocking lever 15 is made in the form of a'toothed segment 28 in 90 gear with a similar segment 29, secured to the stem 30 of the exhaust-valve 11. On the driving shaft 4 is secured the usual eccentric 31, (diagrammatically represented in Fig. 5,)

'connected by well-known means toa stud 32 95 on the arm 16, which rocks vthe lever 15 and operates simultaneously the inlet and exhaust valves.

Referring now to the diagrammatic view Fig. 5, it will there be seen that'the piston 2 is at the rear end of the cylinder 1, the inlet and exhaust valves closed, and the segments 28 and 29 in intermediate position, the eccentric havinga lead of a quarter-revolution. It will also be observed that the oscillating lever 22 lies in horizontal position., the weights 27 rest on their seats, and the headed ends of the rods 4 in contact with the under side of the weights. Assuming that the crank 4 is turning in the direction indicated by the arrow, the momentum of the fly-wheel will carry the connecting-rod beyond or past the dead-center, which will cause the crank connection 33 to move for a short distance in a su bstantialrly vertical direction, the piston 2 moving forward a slight distance only. The eccentric at the same time having a quarter-lead will cause the connection between itself and the valve mechan ism to move in a horizontal direction and rock the lever 15 on its axis. This movement being for the moment so much more rapid than the movement of the piston 2, the exhaust-valve will be opened by means of the segments 28 and 29'to' permit steam in front of the piston to escape, while at the same time the camplate 17, engaging the cam-plate 21, will rock the inlet-valve and admit steam to the cylin der behind the piston, driving it forward.

. When the piston arrives at half-stroke position, as represented by Fig. 6, the cam will be in position to disengage the cam-plate 21, which latter, with the inlet-valve 9 and oscil lating lever 22, will be immediately returned to the cut-olf position (represented in Fig. 5) by means of the weight 27 at the forward'. end of the cylinder 1, which weight had previously been raised by the oscillating lever 22 turning the inlet-valve 9. The piston 2 will then continue its stroke by the expansion of steam previously admitted. The eccentric in the half-stroke position of the piston will have reached its outward limit of movement and will return to the position shown by Fig. 7 as soon as the piston 2 arrives at its forward end of the cylinder. In this position the valve-gear will be moved in opposite direction toward the rear of the cylinder and op'- erate the inlet and exhaust valves in reverse direction to admit steam to the front of the cylinder and exhaust it upon the opposite end. The movement of the inlet-valve will raise the rear end of the oscillating lever 22, causing the weight 27, connected to that end of the oscillating lever, to be raised, while at the same time the rod 24, connected to its opposite end, will be moved in a downward direction by the weight until the several parts are in position shown by Fig. 8 at the return stroke of the piston. If it be desired to cut off steam at some other point of the strokeV than that shown in the drawings, the lever 17 may be moved the proper distance to or from the axis of the rocking lever 15 to decrease or increase the length of time the cam-plates 17 and 21 remain in contact.

While I have shown and described one form of the invention, it is to be understood that various changes in the form, the operation, size. and minor details of construction may be made without departing fromthe spirit or sacriiicing any of the advantages of the invention.

Having thus described the invention, what is claimed as new, and desired to be secured by Letters Patent, is-

1. In a valve-gear for engines, a rocking lever operated by the eccentric of the engine, an inlet-valve and an exhaust-valve, a fixed arm on the stem of the inlet-valve and provided with a cam-plate, a coacting cam-plate attached to the rocking lever, means for operating the exhaust-valve by said rocking lever and gravitating means for closing the inlet-valve.

2. In a valve-gear for engines, an inlet and an exhaust valve, a rocking lever for operating the valves, a cam-plate fixed to the stem of the inlet-valve, an adjustable cam-plate attached to the rocking lever, an oscillating lever also attached to the stem of the inlet-valve and a weight connected to each end of said lever.

3. In avalve-gear for engines, aninlet-valve and an exhaust-valve, means for operating said valves, a camplate attached to the stem of the inlet-valve, an adjustable cam-plate attached to and forming a part of said valve-operating means, an oscillating lever also attached to the stem of the inlet-valve, a rod flexibly pivoted to each end of said oscillating lever and a weight carried by each lever.

4. In a valve-gear for engines an inlet and an exhaust valve, a rocking lever adapted to operate said valves, a cam-plate iixed to the stem of the inlet-valve, a similar cam-plate adjustably secured to the rocking lever to act on first-mentioned cam-plate for opening the said valve, and means for closing said inletvalve after said cam-plates have become disconnected from each other.

5. A valve-gear for engines comprising inlet and exhaust valves, a rocking lever consisting of a straight portion and a toothed segmental portion, a segment on the stem of the exhaust-valve arranged to be operated by said segmental portion, a cam-plate adjustably attached to the straight portion of said rocking lever, a similar cam-plate attached to the stem of the inlet-valve and adapted to be oscillated in either direction by said adjustable cam'- plate, and gravitating means for closing the inlet-valve when said cam-plates becomeV disengaged from each other.

6. A valve-gear comprising an inlet and an exhaust valve, means for positively operating the same, an oscillating lever attached to the stem of the inlet-valve, a rod flexibly pivoted to each end of said oscillating lever, a weight IOO slidably mounted on each of said rods, and a casing for each Weight provided with a stop or rest for said Weight.

7 A valve-gear for engines comprising an inlet and an exhaust valve, means for operating said valves, means for opening the inletvalve for a predetermined length of time, an oscillating lever iXed to the stem of the inletvalve, a headed rod flexibly pivoted to each end of said oscillating lever, a Weight having an opening through which said rod may freely pass, a casing for each of said Weights and a stop or rest in said casings to support said Weights.

In testimony whereof I afHX my signature in I 5 presence of two Witnesses.

FRANK S. SCHMITH. Witnesses:

J. H. VVIERSUM, ALEX. RITTER.

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