US764411A - Valve mechanism. - Google Patents

Description

. PATENTED JULY 5, 1904.

T. H. ALEXANDER.

- VALVE MECHANISM.

APPLIOA JIION FILED JAN 16, I904.

N0 MODEL.

qwhuzaaca Patented July 5, 1904-.

PATENT OFFICE.

THOMAS H. ALEXANDER, OF KENSINGTON, VICTORIA, AUSTRALIA.

VALVE MECHANISM.

SPECIFICATION forming part of Letters Patent No. 764,411, dated July '5, 1904.

Application filed January 16, 1904. Serial No. 189,380. (No model.)

To all whom it may concern:

Be it known that I, THOMAS HENRY ALEX- ANDER, a subject of the King of Great Britain and Ireland, residing at Kensington, in the State of Victoria, Commonwealth of Australia, have invented certain new and useful Improvements in Valve Mechanism for Reciprocating Engines; and I do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same.

This invention consists in improved valve mechanism for reciprocating engines, particularly double-acting steam-engines. I employ a valve which is oscillated or partially rotated intermittently, means being provided for determining its stroke by adjusting the gear or mechanism according to the expansive working of the steam and for reversing the engine.

In the drawings herewith the mechanism comprising a valve and valve-gear are shown. Figure 1 represents various parts in side elevation, the steam-chest cover being removed. Fig. 2 shows a plan, partly in horizontal section, of the parts in Fig. 1. Fig. 3 is an elevation of the interior of the steam-chest, the valve being removed to show the valve-seat; andFig. 4: is a vertical section transversely through the valve-disk.

In the figures the valve comprises a disk (4, having a transverse hole or steam-port 7), and exhaust-port in the form of an arc-shaped channel 0 on the working face of the valve, which operates in a valve-chest (Z, arranged on the side of the steam-cylinder in the ordinary manner. Disk a is fixed on a spindle c, passing through a stufling-box f on the valvechest cover. A crank gis secured to spindle 0 outside of the valve-chest from connectingrod la and bar 0 which is impelled backward and forward in fixed guides Two cams 70 Z are so arranged as to revolve I with the main crank-shaft m of the engine, and by these cams bar 91 is reeiprocated and by the aforesaid connections oscillates the valve or disk a. These cams alternately set the valve for admission of steam to the cylinder and for cut-oil and consequent expansion.

, Rollers a, provided on bar '1: to make contact with the cams, diminish friction. Two steam-ports 0 and an exhaust-port Q) in the valve-seat connect in the usual manner with the ends of the cylinder and the exhaust-pipe, and the admission and exhaust of steam are controlled by putting each port 0 alternately in communication through port 7) with live steam in the valve-chest and through port 0 with the exhaust-pipe.

To reverse the engine or to alter the expansive working of the steam, the angular position of the proper cam is adjusted-that is, cam 7r; in the former case and cam l in the latter. The reversing-cam 7 is fixed on a sleeve q, set to turn freely on a shaft m. Along part of its length this sleeve either carries a helical thread rand a ring or sheave a, grooved on its internal face to engage thread 1', or a projection from the sheave engages a helical groove in the sleeve. Sheave s is adapted to slide parallel to shaftm and is pro: vented from turning relatively to it by guiderods a, which are fixed ,in a collar 6, secured to said shaft, and pass through holes in the sheave. This sheave is moved longitudinally when required. To effect this, I show a screwed rodw, which can turn in fixed bear ings n, (being furnished with collars w to prevent longitudinal motion,) and has upon its screwed portion a nut y, provided with an extension z, which fits in a groove formed in the outer edge of sheave s. Thus by turning screw w the sheave s is shifted longitudinally on sleeve 7 and rotates it by means of thread 0', setting 7:: (the larger of the cams) into a dilferent angular position upon I the crankshaftm. Cam/r is fixed on the end of sleeve (1, while the smaller cam Z is fixed to a sleeve of larger diameter A.

In order that adjustment of the valve may be effected to allow of the ratio of expansion of steam desired, I provide cam Z on sleeve A, which can turn freely around sleeve 1 and has upon it a thread B, fitting a groove in the internal face of a sheave I), which is adapted to turn with the sleeve 1 by means of rods E,

which pass through holes in said sheave and project from a collar F, formed on sleeve q. To slide sheave D along sleeve A, I provide a screw (Jr, having fixed bearings H, collars I, and nut J similar to corresponding parts already described connected with sheave 8. By operating screw Gr cam Z is caused to take up any desired angular position upon shaft m. Instead of screws 20 and G and the connected parts levers or other suitable means of shiftin g sheaves s D longitudinally and setting the cams may be used.

In the operation ofthis valve-gear cam is at each half-revolution of the shaft on places the port Z) alternately opposite each of the steamports 0, thus admitting steam from chest (Z alternately to the respective ends of the cylinder; but as by turning cam k relatively to shaft on the point of the revolution at which this takes place is altered the engine may thus be caused at will to revolve in either direction.

The expansion-adjustment cam Zis made of such length that it can return valve a from its extreme position in either direction in which it has been placed by the cam 70 to an intermediate position in which the port 0 which was previously open to steam shall be closed by the dead portion of the valve between ports 6 and 0 while still leaving the opposite port 0 open to exhaust. The steam already in the cylinder thus expands to the end of the stroke, whereupon the valve ct is set in its other extreme position by the cam A.

What I claim as my invention, and desire to I secure by Letters Patent of the United States,

, which consists in means for changing the angularity of one of said cams whereby the engine may be reversed, substantially as described.

2. In a valve-gear for reciprocating engines, comprising a plurality of cams and a valve controlled thereby, the improvement which consists in means for changing the angularity of each of said cams independently of the other for the purposes substantially as described.

3. In a valve-gear for reciprocating engines, two cams having their throw in opposition adapted to control the admission and expansion of the steam, a valve connected to be operated by said cams, means for actuating said cams and means for altering the angularity of one of said cams whereby the engine may be reversed, substantially as described.

l. In a valve-gear for reciprocating engines, two cams having their throw in opposition adapted to control the admission and expansion of the steam, a valve connected to be operated by said cams, means for actuating said cams and means for altering the angularity of both of said cams whereby the engine may be reversed andthe point of cut-off may be changed at will, substantially as described.

5. In a valve-gear for reciprocating engines, two cams having their throw in opposition, adapted to coiitrol the admission and expansion of the steam, a valve connected to be operated by said cams, means for actuating said cams and means for altering the angularity of each of said cams independently of the other whereby the engine may be reversed and the point of cut-off may be changed at will, substantially as described.

6. In a valve-gear for reciprocating engines, two cams having their throw in opposition, a valve, operative mechanism between said cams and said valve constructed to engage with said cams and control the points of admission and cut-off of the steam to the cylinder, means for actuating said cams and means for altering the angularity of each of said cams whereby the engine may be reversed and the point of cut-ofi' may be changed at will, substantially as described.

7 In a valve-gear for reciprocating engines, the combination with the crank-shaft, of a plurality of sleeves mounted thereon connected to rotate with said shaft, cams mounted on each of said sleeves, and means for rotating each of said sleeves upon said shaft independently of the other thereby changing the angularity of said cams for the purposes substantially as described.

8. In a valve-gear for reciprocating engines, the combination'with the-crank-shaft, of a sleeve mounted thereon, a second sleeve mounted on said first sleeve, both connected to rotate with said shaft, cams mounted on each of said sleeves, and means for rotating said sleeves upon said shaft thereby changing the angularity of said cams for the purposes substantially as described.

9. In a valve-gear for reciprocating engines, the combination with the crank-shaft, of a plurality of sleeves mounted thereon connected to rotate with said shaft, cams mounted on each of said sleeves, a valve connected to be operated by said cams, and means for rotating each of said sleeves upon said shaft thereby changing the angularity of said cams for the purposes substantially as described.

10. In a valve-gear for reciprocating engines, the combination with the crank-shaft, of a sleeve mounted thereon provided with a thread of substantially helical form on its exterior, a cam and a sheave mounted on said sleeve, and means for sliding said sheave on said helical thread thereby rotating said sleeve upon said shaft and changing the angularity of said cam for the purpose substantially as described.

11. In a valve-gear for reciprocating engines, the combination with the crank-shaft, of a sleeve mounted thereon, a cam and a sheave mounted on said sleeve, means for slid ing said sheave on said sleeve and means on said sleeve for engaging with said sheave and rotatingsaid sleeve upon said shaft thereby changing the angularity of said cam for the purpose substantially as described.

12. In a valve-gear for reciprocating engines, the combination with the crank-shaft, of a plurality of sleeves mounted thereon conneeted to rotate with said shaft, cams and sheaves mounted on each of said sleeves, independent means for sliding said sheaves on their respective sleeves and means on said sleeves for engaging with said sheaves and rotating said sleeves upon said shaft thereby changing the angularity of said cams for the purposes substantially as described.

13. In a valve-gear for reciprocating engines, the combination with the crank-shaft, of aplurality of sleeves mounted thereon, each provided With a thread of substantially helical form on its exterior, a cam and a sheave mounted on each of said sleeves and independent means for sliding said sheaves on their respective sleeves in engagement with said threads and rotating said sleeves upon said shaft, thereby changing the angularity of said cams for the purposes substantially as described.

14. In a valve-gear for reciprocating engines comprising two cams connected to rotate with the crank-shaft and a valve controlled 3 by said cams, two sleeves mounted one on the plurality of sleeves mounted on the crankshaft and. carrying said cam-s, a sheave mounted on each of said sleeves, means for sliding said sheaves on said sleeves parallel to the crank-shaft and means on said sleeves for engaging with said sheaves and rotating said sleeves upon said shaft, substantially as described.

16. In a valve-gear for reciprocating engines comprising a plurality of cams and a valve controlled thereby, means for changing the angularity of said earns consisting of a plurality of sleeves mounted on the crank-shaft and carrying said earns, a sheave mounted on each of said sleeves, means for sliding said sheaves on said sleeves, guide-rods for said sheaves secured to the crank-shaft whereby a motionparallel to the shaft is secured, and means on said sleeves for engaging with said sheaves and rotating said sleeves upon said shaft, substantially as described. I

17. In a valve-gear for reciprocating engines, comprising a plurality of cams and a valve controlled thereby, means for changing the angularity of said cams consisting of a plurality of sleeves mounted on the crank-shaft and carrying said earns, a thread of substantially helical form on the exterior of each of said sleeves, a sheave mounted on each of said sleeves constructed to engage with said thread and means for sliding said sheaves parallel to the crank-shaft on said threads whereby said sleeves are rotated, substantially as described.

18. In a valve-gear for reciprocating engines comprising a plurality of cams and a valve controlled thereby, means for changing the angularity of said cams consisting of a plurality of sleeves mounted on the crank-shaft and carrying said cams, a thread of substantially helical form on the exterior of each of a THOMAS H. ALEXANDER.

\ Vitnesses:

G. G. TURRI, JOHN P. BRAY.

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