US627886A - Valve-gear and governor mechanism for steam-engines. - Google Patents

Description

Patented June 27, I899.

a. ALLFREE. VALVE GEAR AND GOVERNOR MECHANISM FOR STEAM ENGINES.

(Apialication filed June 7, 1897.)

(No Model) 3 Sheath-Shae! I.

( 11 U0 1 1 for- Jdm 7 jmyfce? YIRS :0, FNDTO-LITNQ, wAsmNsmN, n. a.

No. 627,886. Patented June 27, I899.

.1. B. ALLFREE.

VALVE GEAR AND GOVERNOR MECHANISM FOR STEAM ENGINES.

(Lpplicatma filed June 7, 1897.]

3 Shoets-8heet 2.

(N0 Model.)

fires,

No. 627,886 Patented June 27, I899.

J. B. ALLFBEE. VALVE GEAR AND GOVERNOR MECHANISM FOR STEAM ENGINES (Application filed June 7, 1897.1 (No Model.)

3 Sheets-Sheet 3.

UNITED STATES PATENT FFICE.

JAMES B. ALLFREE, OF INDIANAPOLIS, INDIANA.

VALVE-GEAR AND GOVERNOR MECHANISM FOR STEAM=ENGINES-J SPECIFICATION forming part of Letters Patent No. 627,886, dated June 27, 1899.

Applieationiiled June 7. 1897.

To all whom it may concern:

Be it known that I, JAMES B. ALLFREE, a

citizen of the United States,residing at Indian apolis, in the county of Marion and State of Indiana, have invented certain new and useful Improvements in Valve-Gears and Grovernor Mechanism for Steam-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 make and use the same. My invention relates to valve-gear for engines, and more particularly to a specific form of my improved valve-gear disclosed and claimed in my Patent No. 613,184, dated October 25, 1895, the present embodiment of my invention being especially adapted for application directly to the main-valve-operating eccentric.

The objects of my invention are to provide a valve-gear which will impart to the valve,

first, quick movements for opening and closing the admission and the exhaust, thereby avoiding wiredrawing of the steam or other actuatingfluid and permitting a greater range of cut-off, and, second, retarded movements to cause the valve to dwell or stop after the close of admission and to delay the closing of the exhaust, all during each stroke of the piston. The advantages derived from this mode of operating the valve are all fully set forth in my prior patent above mentioned and need not be set forth here in detail. Suffice it to say that the quick opening and closing of admission insure an initial pressure in the cylinder more nearly approaching the boilerpressure, because wiredrawing is avoided, and permits a greater range of cut-off, while the delay after close of admission permits the steam to be retained in the cylinder a longer time,and the delay before the close of exhaust afiords a free and unobstructed exhaust, thereby avoiding undue compression, all of which increases the effective work of the steam.

I accomplish the objects of my present invention by imparting an auxiliary movement to the eccentric, whereby the primary movement imparted to the valve by the eccentric will be augmented at certain points of its travel and diminished at other points, thus enabling the valve to begin opening later,

Serial No. 639,713. (No model.)

thereby avoiding undue lead and obtaining a much larger opening, and yet by closing much sooner I am enabled to obtain an earlier cut-0d. Then again by the slower or delayed movement of the valve between the closure of the admission of the steam and the release or opening of the exhaust I obtain a fuller and more perfect expansion more nearly equaling the full pressure or value of the steam, or, in other words, I am enabled by this my invention to obtain a sufficient open ing to practically reach boiler-pressure and cut-off in time to reach atmosphere when the steam is released. In short, I accomplish by this means with a high-speed engine practically the same results as are obtained by the engine, showing the position of the valve and piston for the corresponding position of the valve-gear shown in the other views of the drawings. Fig. 2 is a view in elevation of sufficient of an engine to show my improvements applied thereto. Fig. 3 is a view in side elevation of my improved mechanism applied to the governor-wheel. Figs. 4 and 5 illustrate different forms of cams from that which is shown in Fig. 3; and Fig. 6 isasection on the line 6 6, Fig. 3.

The drawings show an engine in which the steam is cutoff at one-quarter of the stroke of the piston.

' Referring to the drawings, in which the same reference characters relate to the same or corresponding parts in all the views, the letter A designates a governor-wheel having arms A, upon one ofwhich arms is a hub a, in which is mounted a transverse shaft 0, secured to or formed integral with which shaft is an eccentrically-arranged pin O.' The eccentric B, which is of an ordinary Variable form, is carried by the governor-frame B, the latter being pivotally attached to the eccentric-pin G. v

E is a lever which is pivoted at e to an arm of the governor-wheel. The long arm E carries the adjustable weight E the tendency of which is to move out by centrifugal action when the wheel rotates. This outward tend ency will be counteracted by the spring F,

which is connected at one end with the lever and at the other with the rim or other part of the wheel. The short arm of the lever E is connected with the frame B by means of the link G in the manner as clearly shown in the drawings. This provides a centrifugal governor, by which the eccentric will be automatically shifted to keep the engine within regulation speed; but as other forms of automatic governors can be used with my improvement I do not wish to limit this invention to the form here shown.

Keyed or otherwise securely fastened to the end of the shaft 0 opposite that which carries the eccentric-pin C is an arm J, by the movement of which arm it is obvious that a swinging movement will be imparted to the frame B, because of the eccentricity of the pin 0, to which the frame is pivoted at one of its ends, and in order to secure the necessary movement of said arm at the moment the valve reaches the line of cut-off and to cause the arm J to swing out and back quickly, therebyimpartinga corresponding movement to the eccentric, I provide the arm J with a roller J on its free end, which roller engages a cam K, held in a stationary position opposite the hub of the governor-wheel, the roller being held constantly against the face of the cam by suitable means, such as a spring L, which has one end fastened to the arm J and the other end fastened to one of the arms of the governor-wheel.

Referring to Fig. 3, y y represents the line of cut-off, and if it is desired to increase the opening from M to M the position of the arm J to give the required increase will be ascertained by making the distance M M equal to the distance M M Then a line drawn through the center of revolution of the swinging arm J and the point- M will intersect the orbit of the axis of the roller J at the new center of the roller when the latter is in the position to give the eccentric its maximum augmental movement required to increase the opening from M to M The dotted lines show the position of the roller, and to force it out into position acam must be used, the highest point of which will force the roller out the desired distance. The cam should be provided with easy curves, which lead up to and away from this highest point to secure smooth and easy running of the engine.

To act on the valve at both ends of its stroke, it is necessary to duplicate the cam on the opposite side of the governor-wheel in the manner as shown in the drawings. A. reduced portion N of the crank-shaft N projects from the end of the shaft, and the cam K is mounted on this reduced portion. The shaft rotates while the cam is held in a stationary position by means of the handle-bar K A standard K fastened to the frame of the engine and to which the handle-bar is adj ustably secured, provides means for retaining any desired adjustment of the handle-bar and enables the cam after it has been brought into harmony with the rest of the engine to be locked to the desired position.

' der certain conditions.

By the adjustment of the cam the lead and cut-off will be accomplished earlier or later in the stroke and 0bviously may be accomplished while the engine is in operation. By this construction the swinging of the arm J under the action of the cam as the said arm is moved around by the governor wheel will impart alternate movements of oscillation to the shaft 0, which will, through the medium-of the eccentric-pin, oscillate the frame B, thus causing the eccentric B to swing in one direction, so as to augment its movement when the motions of the eccentric and the modifying or controlling mechanism are together and to retard or to subtract from the movement of the eccentric upon the return movement of the arm when the said motions are opposed to each other, and when the two motions are so timed as to be equal and opposite the resultant motion will cause a dwell or stop in the travel of the valve, which is arranged to occur after the close of admission and before the close of exhaust. Such effect may be a complete stop or only a sufficient retardation or dwell as to prevent effective movement of the valve at the points designated.

The contour of the cam between its two ends may be varied to suit the conditions and results desired. Fig. 3 shows a cam with straight sides, Fig. 4 one with arched sides, and Fig. 5 a cam with hollowed or concave sides. The line of travel from one end-of the cam to the other is greatest in the pattern.

shown in Fig. 5 and would be preferable un- L to press the roller against the cam a slotted or grooved cam to receive the roller and slide itin its required path might be employed.

It is believed the drawings illustrate my invention so clearly that further description is unnecessary.

The broad features of my invention, consisting in the use of an auxiliary or modifying device connected to the main valve-gear and so disposed as to influence the movement of such main valve-gear in order that resultant movements imparted to the main valvegear by the modifying valve-gear will effect a quick opening and closing of the admission.

and exhaust and a retardation, dwell, or stop after the close of admission and before the close of exhaust during each stroke of the piston, are claimed in my Patent No. 613,184, hereinbefore mentioned, and hence I do not herein claim such generic form of my invention, the present embodiment of my invention being the application of that form ofmy invention in which the modifying or controling valve-gear is connected directly to the main eccentric whether that eccentric be a shifting or non-variable eccentric.

I claim as my invention- I. In a steam-engine, the combination with the steam-distributing valve, and a valve-operatiug eccentric, of a stationary cam, a piv:

otal lever-arm having its free end directed Instead of the spring toward said cam and having motion of rotation around said cam, means whereby the free end of said arm is constrained to move in the path described by the contour of said cam and for connecting said arm to said eccentric for changing the position thereof, substan tially as set forth.

2. In a steam-engine, the combination with the steam-distributing valve and a valve-optric having a variable throw and means for automatically varying the throw thereof, of a lever-arm pivoted at one end and having its free end constrained to travel in fixed determined path, and means for connecting said arm to said main eccentric, whereby an additional movement will be imparted to the latter eccentric separatefrom and independently of the movement imparted to it by the automatic operating means.

4. In a steam-engine,a rotating shaft, a governor-wheel mounted on said shaft, a pivot eccentric to a rocking shaft mounted on the wheel, a frame oscillating about the eccentric pivot, an automatic centrifugal governor connected with and operating the oscillating frame, an eccentric mounted on the frame, and an engine-valve connected with and actuated by the eccentric, substantially as described.

5. The combinationwith the valve of an engine, a rotating shaft, a governor-wheel mounted on the shaft, a pivot eccentric to a rocking shaft supported by the wheel,a frame oscillating around the eccentric pivot, a centrifugal governor connected with the frame and an eccentric mounted on the frame and connected with the valve of the engine, of an arm mounted on the shaft carrying the eccentric pivot and moving-with the said shaft, a roller'on the end of the arm, and a stationary cam around which the roller travels, substantially as described.

6. The combination with a'rotating shaft, a goyernor-wheel mounted on the shaft, an eccentric, governor-frame carrying the eccentric and oscillating around aneccentric pivot, an arm moving with the shaft which carries the eccentric pivot, and a roller on the end of the arm, of a cam around the'periphery of which the roller travels at every revolution of the crank-shaft, and means for adjusting said cam in different positions, substantially as shaft 0 mounted on the arm of the governorwheel andhaving the eccentric-pin C around which the frame B oscillates, the arm J moving with the shaft 0, the roller J mounted on the arm J, the cam K supported in a stationary position opposite the end of the crank, means for forcing the roller constantly against the cam, and means, substantially as described, for adjusting the position of the cam.

8. In combination with the governor-wheel of an engine, an eccentric mounted upon said wheel and connected to the valve, a modifying or controlling device carried by the wheel and connected to the eccentric, with mechanism arranged to act upon said modifying device so as to cause the said device to alternately act in conjunction with and 0ppose the said eccentric, as the wheel rotates, whereby the resultant motion imparted to valve by the eccentric causes an acceleration in the travel of the valve to open and close the admission and exhaust and to retard the travel of said valve until it dwells or stops after the close of admission and before the close or exhaust during eachstroke of the piston.

9. The combination with the'valve of a rotating shaft, a wheel mounted on said shaft, an eccentric on said wheel connected to the valve, controlling mechanism carried by the wheel and connected to said eccentric and stationary devices arranged to act upon said -controlling mechanism as the wheel revolves and so constructed as to cause said controlling mechanism to operate first, in conjunction with the movement of the eccentric to cause said eccentric to-im part an accelerated travel to valve to open and close the admis- 'sion and exhaust, and second, to oppose the movement of the eccentric to cause the said eccentric to retardthe travel of the valve after-the close of admission and before the close of exhaust, during each stroke of the piston, substantially as described.

10. The combination with the valve, of a rotating shaft, a wheel mounted on said shaft, a frame on said wheel pivotally connected thereto, an eccentric carried by the frame, an

arm connected to said frame eccentrically to the pivotal connection of the said frame with the wheel, and stationary cams arranged to act upon the arm so as to cause it to move the frame at predetermined points during the revolution-of the wheel, whereby the eccen-v IIO ed upon said shaft; an eccentric carried by the wheel and operated by the rotation of said wheel, connections between the ,eccen-' trio and valve, mechanism for modifying the movements of the eccentric carried by the wheel and connected to the eccentric, and stationary devices adapted to act intermit-I tently upon said modifying mechanism during the rotation of the wheel, whereby the said eccentric is caused to impart alternately accelerated and retarded movements to the i Valve, so as to cause the said valve to quickly open and close the admission and exhaust ports and dwell or stop after the close of admission and before the close of exhaust.

In testimony whereof I aflix my signature in the presence of two witnesses.

JAMES B. ALLFREE.

Witnesses:

B. BERTERMANN, JOSEPH A. MINTURN.

Images