US696918A - Steam-engine governor. - Google Patents

Description

No. 696,9l8. Patented A ia 8, I902.

J. B. ALLFREE. v

STEAM ENGINE GUVERNOR.

(Application filed May 24, 1699.]

(No Model.)

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UNITED STATES PATENT rrrcn.

JAMES B. ALLFREE, OF INDIANAPOLIS, INDIANA.

STEAM-ENGINE GOVERNOR.

$PEGIFIOATION forming part of Letters Patent No. 696,918, dated April 8, 1902. Application filed May 24,1899. Serial No. 717,979. (No model.)

To to whom it may concern:

Be it known that I, J AMES B. ALLFREE, a citizen of the United States, residing at Indianapolis, in the county of Marion and State of Indiana, have invented certain new and useful Improvements in Steam-Engine Governors, of which the following specification is a full description.

My invention relates to that class of governors commonly known as shaft-governors, and is of the shifting eccentric type and operates by varying the travel of the steamdistributing valve, and has for its object the production of a shaft-governor that may be operated at speeds lower than has heretofore been possible. It is well known that great difficulties have attended all efiorts to operate shaft-governors at what may be termed relatively low speeds. For the purpose of treating this subject more comprehensively I will assume and designate all speeds above, say, two hundred and fifty revolutions per minute as high, all speeds below one hundred and fifty revolutions per minute as low, and between these two rates as medium.

The difficulties in the effort to operate shaftgovernors at low speeds arise principally from their lack of perfect gravity balance, or, in other words, if the spring were removed the working parts should remain in whatever position they were placed in without being influenced by gravity. As a result of this lack of gravity balance the tendency is for the Weight masses to respond more readily to gravity, this tendency getting worse as the rate of travel of the weight approaches or falls below the natural rate of gravity. On the contrary, where the rate of travel of the weight masses is considerably in excess of the rate of gravity an unbalanced governor will operate successfully where the centrifugal force increases the friction to a point where binding at bearing-points would result when it is to be preferred for the very obvious reason that the vibratory action due to its unbalanced condition effectually prevents the tendency of the governor to find and remain in a fixed position. Ahigher degree of refinement of regulation may be expected by reason of any fixed or set position being avoided; but, on the contrary, as the speed becomes lower these vibrations become longer and more noticeable until surging or racing results. In my governor I overcome this difficulty by so disposing the parts as to bring each active member in opposition to its mate with relation to gravity,and as a resultI have attained a perfect equipoise of all parts in relation to the force of gravity at any speed or position and an absolute equilibration of all effective centrifugal forces and have located the weights at such a point beyond the tangential line as will most effectively combine inertia with centrifugal force, whereby the governing action is rendered most sensitive to changes of load, and speed is maintained at a practically constant rate, and means for readily adjusting the spring and weights that perfect isochronism may be effected between said spring and weights, and as a result of all these special features a governor is produced that is extremely stable in position while at the same time being most sensitive to changes of load. To this end I mount my weighted levers on shafts as near as practical to the engine-shaft, with their weighted portions in such position as to give the greatest amount of inertia consistent with a sufficient amount of centrifugal force to control the position of the eccentric and obtain the proper stability.

By referring to the drawings it will be observed that I mount my governing-eccentric on one of the pivotal shafts that carries one of the weighted arms and a mass similar in form upon its mate. These pivotal shafts, each carrying one of the weighted arms and being exactly opposite and similar in weight, are exactly contrary in their gravity action, but exert an influence precisely similar with relation to inertia and centrifugal force. In theory a resisting-spring attached to each weighted lever would seem proper; but in practice one is found preferable, because of the difficulty of getting two springs that will elongate precisely the same distance under the same weight.

The construction of my device is fully shown and described in the accompanying drawings and the following specification.

Figure 1 is a side view in elevation of the governor complete, illustrating it as attached to the fly-wheel of an engine. Fig. 2 is a transverse view, partly in section and partly in elevation. Fig. 3 illustrates side and edge views of one of the governor arms or levers and a governor-weight in detail. Fig. 4shows the eccentric in elevation side and edge views in detail, and Fig. 5 are detail side and edge views in elevation of an eccentric-counterbalance.

a, is the carrierof the entire governor mechanism and is here represented as a fly-wheel of an engine.

at is the hub.

a is the engine-shaft upon which the flywheel is mounted.

17 represents the weighted arms of the governor, one of which is rigidly mounted'on each of two small shafts, respectively, b and b Said shafts b and b are movably mounted in suitable bearings in or aflixed to the hub of said fly-Wheel a. The governorarms are mounted with the weighted end forward in reference to rotation, as seen in Fig. 1 and are each provided at b with suitable bearing connections for the movable attachment of the parallel coupling-links c, of which there are preferably two. The points of attachment 6 two in each arm, are equidistant from center of respective shafts b and 6 At b in one of said governor-arms is a movable attachment for aspring 19 provided with adj usting-screw b, which is secured at outer end by suitable attachment 6 to an arm of said fly-wheel a. The detachable weights b are preferably retained in recesses b at the weight end of said arms b by any simple means, a plain bolt being employed in the present case, facilitating the increasing or decreasing of weights in said governor-arms for the purpose of attaining perfect isochronism between the said spring and weights in said governor-armsthat is to say, that the centrifugal force of the weights due to varying speeds may be resisted at all points within the arc of their oscillation by an equally-varying spring tension-all of which is readily accomplished by the changing of weights and adjustment of spring tension.

b is a stop, in this case secured to the rim of fly-wheel and adapted at each end to limit the distance of oscillation of the governorarms as the lug I), provided on one of said arms, strikes against said stop, the outer limit of oscillation being shown by dotted lines I), when the lug b will strike against the shorter arm of said stop. The said stop is preferably so constructed that the points against which the governor-weight impinges are slightly compressible or yielding, so as to soften the shocks.

d is the eccentric, which is adapted to receive on its outer periphery an eccentric strap or yoke whereby to communicate motion to a steam-distribution valve or valve mechanism and is rigidly secured at hub 01 to one end of the small shaft 17" at opposite end from that to which one of said governor-arms is socured, said eccentric in this instance being adapted to surround the main shaft a and of sufficient compass within the space d to ad'- mit of shifting by oscillation upon its eccentric axis at d.

e is an eccentric counteracting balance adapted to counteract the forces of gravity and centrifugal action in said eccentric and connections and. is mounted rigidly at e on oscillating shaft 12 on opposite end from that at which the respective governor-arm is attached, and. is of suitable size of inner opening to oscillate freely outside the hub d of said eccentric.

It is now readily seen that the governorarms being mounted at points of oscillation diametrically opposite and equal in all respects and connected in parallel position at points equidistant from points of oscillation and by equal connecting-links, one of said arms carrying, by means of the intervening shaft, an eccentric and the other arm carrying an eccentric-weight equaling in all respects the efiects of gravitation andcentrifugal forces acting upon said eccentric, that the entire mechanism is most perfectly balanced at all times either standing or running at whatever rate of speed, and in practice these conditions being assured the isochronal relation between the weights and spring can be most readily attained by adjustments already described, and while there are various structural changes that might be resorted to without departing from the spirit and scope of my invention, which I deem myself at liberty to make,

What I claim as new, and desire to secure by Letters Patent, is-

1. The combination with a rotating carrier and ashifting eccentric pivoted thereto, a contrifugal governor-arm attached to said eccentric by means of which the latter is shifted, a counteracting balance-weight pivoted at a point diametrically opposite from said eccentric to said carrier, a centrifugal governorarm attached to said counteracting balanceweight adapted to swing it in opposition to the shifting of said eccentric, and means interposed between said governor-arms controlling them to move in unison.

2. The combination with a rotating carrier an eccentric and the governor-arm by which it is swung, pivotally connected to said carrier, a counteracting balance-weight and the governor-arm connected thereto, adapted to swing said weight in opposition to the shifting of said eccentric being pivotally connected to said carrier at a point diametrically opposite from pivotal point of said eccentric, a link connection between the two said governor-arms, controlling them to move in unison, and masses of weight located on said governor-arms at a point forwardly and outwardly in relation to said pivotal points, that the combined action of inertia and centrifugal forces may be caused to act in the movement of the said eccentric and counteracting balance-Weight.

3. The combination with a rotating carrier, an eccentric and the governor-arm by which it is swung, pivotally connected to said carrier, a counteracting balance-weight and the governor-arm connected thereto adapted to swing said weight in opposition to the shifting of said eccentric, said weight and arm being pivotally connected to said carrier at a point diametrically opposite from pivotal point of said eccentric, a mass of weight on each governor-arm located in a forwardly and outwardly position in relation to thepivotal point of said arms whereby inertia and centrifugal forces are caused to act in combination in the oscillation of said eccentric and counteracting weight, a link connection interposed between the two governor-arms controlling them to act in unison, a spring adapted to resist the combined inertia and centrifugal forces and means for adjusting said spring.

4. The combination with a rotating wheel or carrier, an eccentric and a pivot-shaft to one end of which it is secured, a weighted governor-arm secured at midway of its length to opposite end of said pivot-shaft, a counteracting balance-weight secured to one end of a second pivot-shaft, said pivot-shafts being mounted at points equidistant from center of rotating carrier and diametrically opposite from each other, a weighted governor-arm secured to second said pivot-shat t at opposite end from said counteracting balance-weight and in the same position in relation to rotation of said carrier as former said governorarm and secured likewise at midway of its length to respective pivot-shaft, weights located at a point outside of a tangential line in relation to the rotation of pivotal points on said governor-arms, that a combined effect of inertia and centrifugal forces result in action and links connecting to the weighted end of each said governor-arms the lever end of the other controlling them to move in unison.

5. The combination with a rotating wheel or carrier, an eccentric and a governor-arm attached at center of length to said eccentric, both mounted at a common pivotal point eccentrically in said carrier, an eccentric counteracting balance-weight and a second governor-arm attached at center of its length to said weight, and both likewise mounted at a common pivotal point diametrically opposite from pivotal point of said eccentric and equidistant from center, in said carrier, weights mounted on forward ends of said governorarms and located outside of a tangential line drawn from the pivotal points of said arms so that the combined effect of inertia and centrifugal forces are called into action at slightest Variations of speed, links interposed between said governor-arms connecting the lever end of each arm to the head or weighted end of the other arm controlling said arms to move in unison, and a spring exerting centripetal force tending to counteract the centrifugal force exerted by the combined oscillating mechanism as set forth.

6. The combination with a rotating carrier or wheel, an eccentric and a governor-arm attached at midway of its length to said eccentric, and pivoted with the eccentric at a point outside of center of the axis of said carrier, an eccentric counteracting balanceweight and a governor-arm attached midway of its length thereto, and pivoted with said balancewveight at a diametrically opposite and equidistant point from center of the axis of said carrier and from former said governor-arm and eccentric, the weighted end of said governor-arms projecting forward in relation to rotation of said carrier, links pivotally connected between said governor-arms connecting the lever end of each arm to the head or forward end of the other, and the eccentric and balance-weight being equal and playing in opposite directions over the axis of the carrier, the mechanism is most accurately balanced as to gravity or runningbal ance, weights fixed at forward or head end of said governor-arms at a point outside of a tangential line throughsaid pivotal points, so that inertia and centrifugal forces act in combination, and a spring adapted to exert centripetal force against the combined inertia and centrifugal forces, and means for adjusting said spring, one end of said spring preferably being attached to one of said governor-arms, and the other anchored as in this case at or near a peripheral point in said wheel at an angle giving the greatest efiect; all parts being equal and paired in opposition as to effect of gravity, so as to produce perfect equipoise, either in or out of action.

In testimony whereof I have subscribed my name. v

JAMES B. ALIJFREE.

Witnesses:

A. L. TEETOR, E. B. HETZEL.

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