US526484A

US526484A - Valve mechanism

Info

Publication number: US526484A
Authority: US
Publication date: 1894-09-25
Anticipated expiration: 1911-09-25

Description

(No Model.) 3 Sheets-Sheet l.

D. A. DBGROW. VALVE MBGHANISM.

Patented Sept.'25, 1894.

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D. A. DEGROW.

VALVE MEGHANISM. No. 526,484. Patented Sept. 25, 1894.

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D. LDEGROW. VALVE MECHANISM.

No. 526,484. Patented Sept. 25,1894;

W/ r/vass E6! //v VEN Tq R UNITED STATES PATENT OFFICE.

DAVID A. DEOROW, OF LOGKPORT, NEW YORK.

VALVEMECHANISM.

SPECTFICATION forming part of Letters Patent No. 526,484, dated September 25, 1894.

Application filed May 28, 1894.

To all whom it may concern:

Be it known that I, DAVID A. Dnoaow, a citizen of the United States, residing at Lockport, in the county of Niagara and State of New York, have invented new and useful Improvements in Valve Mechanism of Steam-Engines, of which the. following is a specification.

This invention relates to the valve mechanism of steam. engines, and particularly to the valve mechanism of that classof steam engines known as liberating-cut off.

The object of this invention is the provision of mechanism for controlling the cut-off devices whereby a range of cut-H may be obtained extending from a point at the beginning of the stroke to any point throughout 1 the entire or full stroke of the engine.

With this object in View the invention consists substantially in the construction, combinations, location and relative arrangement of parts, all as shown in the accompanying drawings, as more fully hereinafter set forth, and finally pointed out in the appended claims.

In the drawings Figure 1 is a detail view in front elevation of mechanism embodying the principles of my invention. Fig. 2 is a plan view of the construction shown in Fig. 1. Fig. 3 is a detail view in side elevation of the pivoted latches detached from the valve stem. Fig. 4 is a detail View in front elevation of the latches, as shown in Fig. 3. Fig. 5 is a detail view in front elevation of the knockoff arm for releasing the valve during the first part of the stroke of the engine. Fig. 6 is a detail view in plan of the construction shown in Fig. 5. Fig. 7 is a detail view in front elevation of the knock-01f arm for releasing the valve during the last part of the stroke of the engine. Fig. 8 is a detail View in plan of the construction shown in Fig. 7. Fig. 9 is a-view in end elevation ofthe knock; ofi arm shown in Figs. 7 and 8. Fig. 10 is a general view in front elevation showing my improved valve liberating and cutoff mechanism, as applied to a vertical steam cylinder. Referring to the drawings, wherein the same reference sign is used to designate the same part wherever it occurs throughout the several views, 1 designates the inletvalve stem. Suitably mounted on valve stem 1 is an arm Serial No. 512,776. (No model.)

2, the hub of which may be secured to the valve stem in any suitable way, as by a pin, spline, key or set-screw, whereby when said arm is rockedthe valve stem will be rotated in its bearings 28. To the free end of arms 2 are suitably journaled the

dash pots

19, 20,

in the usual way.

The valve motion is driven through an arm 5, the hub of which is loosely sleeved on valve stem 1. Cast with driving arm 5 and hub 29, or otherwise suitably secured thereto, to rock therewith, is an arm, 6, bored transversely at the outer free end thereof to receive a pin 7. Said pin is rigidly secured'in the bore through arm 6 in any suitable way to prevent said pin from turning therein. Loosely mounted on the outer or projecting end of pin 7 to rock therearound as a pivot is a bell crank lever 3, one arm of'which constitutes what I call the primary latch, and is formed with a hook por tion adapted to engage the squared portion of the dash pot arm pin 4, and to be disengaged therefrom, as occasion requires, as will more fully hereinafter appear.

It will beseen that when the primary latch 3 is disengaged from the dash pot arm pin 4, the rocking motion imparted to the valve motion driving arm 5 will not effect a rotation of valve stem 1, inasmuch as said driving arm 5 is loosely sleeved on said stem; but when said primary latch engages the dash pot arm pin 4; any rocking motion imparted to the driving arm 5 will efieot a rocking of the valve stem 1 through hub 29, arm 6, pin 7, bell crank shaped lever 3 and arm 2, the latter being rigidly mounted on the valve stem, as above explained. It is also apparent that when the primary latch 3 is disengaged from the pin 4 a rotary or rocking motion of valve stem 1 is effected independently of the motion of driving arm 5 through

dash pots

19, 20 and arm 2, thus effecting a closing of the valve and the consequent cutting-off of the steam supply. 1

I will now describe the mechanism for antomatically tripping latch 3 to effect the disengagement thereof With pin 4.

Numeral 8 designates What I term the primary knock-off arm. (See Figs. 5 and 6.) This arm is loosely sleeved to rock upon valve stem 1. The hub of the sleeve thereof is provided with a cam projection 16. The outer free end of said arm Sis suitably constructed to receive suitable operating mechanisms presently to be described. Also suitably sleeved to rock upon valve stem 1 is the hub of an arm 9, the arm 9 projecting in a direc-' 'also suitably constructed at the outer free end thereof to receive suit-able operating connections presently to be described. One arm of the bell crank lever constituting the trip latch 3 is arranged in position to be engaged by

cams

16 and 17, whereby the other arm of the said trip latch having the hook may be forced out of engagement with pin 4 at the proper time. In order to keep the trip latch in position to be engaged by said cams and normally in position to engage pin 4 on the dash pot arm, I suitably mount in arm 6 a pin 12 rigidly held in said arm 6 but capable of rotary adjustment by means of nut 30. The free end of said bolt is split and mounted in the split thereof is a strong leaf spring inposition to engage the inner face of the rearwardly projecting arm of the latch 3 and press the same yieldingly into position to be engaged by the same cams as above explained. The rotary adjustment of pin 12 serves to regulate the tension of spring 10. Pivotally other they are pivoted together.

seen from this construction that when one of I hung upon the rear face of the arm of hell crank latch 3 is what I designate the secondary latch 13 pivoted to swing in a direction parallel to the length of the pivot of said latch 3, upon a pivot pin 14:. The secondary latch 13 is held in position by means of a flat spring 15, secured to the front edge of said arm of the latch, which spring serves not only as a stop for said secondary latch, but permits the same to be rocked about its pivot against a yielding resistance. The end of said secondary latch is provided with a toe, as shown (see Fig. 3) which projects beyond the front edge of said primary latch in position to be engaged by the inclined face of cam 17 when the secondary knock-offarin is moved in one direction, whereby the said pin is rocked upon its pivot and the cam permitted to pass the same, as will more fully hereinafter appear.

In the form shown in Fig. 10 I provide two sets of valve mechanisms as above described, and the outer-ends of each pair of primary knock-0E arms 8 are connected by a rod 22. Similarly each pair of secondary knock-off arms 9 are connected by a rod 21. Theposition of one pair of knock-off arms is reversed relatively to the position of the other pair,and consequently

rods

21 and 22 cross each other. At the point 23, where said rods cross each It will be the knock-off arms is moved in one direction the secondary arm of the same pair is simultaneously moved in the opposite direction,

while both the primary and secondary knockofi arms in the other set are by the same movement equally and simultaneously moved in opposite directions and in a direction opposite respectively to the directionin which the arms of the first set move, as will be readily understood, the movement of said arms being a rocking movement around valve stems 1 upon which said arms are loosely sleeved, as above described. The lower primary knock-off arm 8 is connected in a suitable way through rod 24 to the governingmechanism of the engine, whereby the rocking movement of theknock-off arms, and hence the tripping of latch 3 and the movement of valve stems 1 are controlled.- by the governing mech- It will be observed that there are two knockoff arms of each steam valve, adapted to be moved in opposite directions. The function of one knock-off arm is to liberate the cut-0E valve on the forward or first movement of the valve motion, that is, during the first half stroke of the engine, and when so set that the valve is not released on the forward movement of the valve motion the other knock-off arm is provided,the function of whichis that in its motion in the opposite direction it will be in position to release the valve on the return movement of the valve motion, the relative position of the two knock-off arms being such that when one ceases to act the other is in place to effect the liberating of the valve.

The driving arm 5 has the ordinary movement of the Corliss valve, and it moves in the direction of arrow 25 during the first half'of the stroke of the engine, and in the direction of arrow 26 during the last half of the stroke of the engine. (See Fig. 1.) The trip latch 3 moves in unison with driving arm 5, as does the dash pot arm 2 when the trip latch is in engagement with pin 4 of said arm. When ,the driving arm 5 moves in the direction of arrow 25 the rear face of the spring pressed arm of trip latch 3 comes into contact with cam projection 16 on the hub of primary knockoff arm8, whereby the latch 3 is disengaged from the dash pot arm pin 4, allowing the valve to be closed by the action of the

dash pots

19 or 20, as the case may be, the point of the cut-off being varied by the relative position of the knock-off arm 8 as controlled by the governor. If, however, primary knock-off arm 8 has been moved by the governor to a positionthat will prevent cam projection 16 from coming in contact with the rear face of the spring pressed arm of trip 3 during the movement of driving arm 5 in the direction of arrow 25, it is evident that the secondary knock-off arm 9 which has a simultaneous movement in the opposite direction relative to primary knock-off arm 8, has attained a position for cam 17 of the hub thereof to come in contact with latch 13 on the rear face of the spring pressed arm of trip latch 3, eifecting a disengagement of latch 3 from the dash pot arm pin allowing the valve to be closed.

From the above description it willbe seen that the governor and its connection to the knock-ofiarms may by its movement lengthen or shorten the point of cut-off from a point at the beginning to any point throughout the entire or full stroke of the engine.

The primary latch 3 may be of any suitable or well-known construct-ion, adapted to be tripped by the knock-off arms. Thesecondary latch 13 may be of many different shapes or forms, so constructed as to permit cam projection 17 on the hub of knock'ofi arm 9 to pass by the samewithout tripping latch 3 during the first part of the stroke of the engine, but to be engaged by said projection to effect the disengagement of the latch from the dash pot arm when the said knock-off arm is in a position for releasing the cut-off at a point beyond the half stroke of the engine.

The principle of tWo knock-off arms may be applied to any of the existing forms of liberating cut-off valve motions for thepurpose of extending the range of the cut-0E.

While I have shown and described a specific form of mechanism embodying the principles of my invention, I wish it to be distinctly understood that I do not limit myself thereto, as the principles of my invention may be embodied in various forms of mechanism and many variations and changes would readily suggest themselves to any one skilled in the art to which this invention relates and still fall within the scope of my invention.

Having nowfully described my invention and having explained the principles thereof and the form of mechanism embodying the same,what I claim as my own invention, and desire to secure by Letters Patent of the United States, is-

1. In a valve gear for steam engines, means for cutting off steam at any point of the stroke of the engine, comprising a pair of knock-oif arms and means for operating the same and connections between said knock-0E arms and the valve mechanism; as and for the purpose set forth. I

2. In a valve gear for steam engines means for cutting off the steam supply at any point of the stroke of the engine, comprisinga pair of knock-off arms, and means for automatically moving said arms in opposite directions and means operated thereby for controlling the valve mechanism; as and for the purpose set forth.

I 3. In a valve gear for steam engines a valve stem, dash pot, rigid connectionsbetween said stem and dash pot, a valve mechanism, connections between said valve mechanism and dash pot and means for automatically tripping said connections at any point throughout the stroke of the engine, comprising a pair of knock-0E arms; as and for the purpose set forth.

4. In avalve gear for steam engines, the combination of a valve stem and dash pot, rigid connections between said stem. and dash pot, a valve mechanism, connections between said valve mechanism and dash pot, a governor, a pair of knock-0E arms and connections between said governor and knock-0E arms for moving the latter simultaneously in opposite directions, and devices engaged by said knockoff arms for tripping the connections between said valve mechanism and dash pot; as and for the purpose set forth.

5. In a valve gear for steam engines a valve stem, an arm secured thereto to rock therewith, a dash pot attached to the free end of said arm, a valve mechanism mounted on said valve stem, connections between said valve mechanism and dash pot, whereby said valve mechanism, dash pot and arm are moved simultaneously and in unison, a tripping mechanism for disconnecting said connections, comprising a pair of knock-01f arms, a governor and connections between said governor and knock-01f arms for moving said arms simultaneously in opposite directions; as and for the purpose set forth.

6. In a valve gear for steam engines a valve stem, an arm rigidly secured thereto to rock therewith, dash pot carried by said arm, a

valve mechanism, connections between said valve mechanism and dash pot comprising a pivoted latch, means for tripping said latch comprising a pair of knock-01f arms, having cam projections, and means for moving said knock-0d arms simultaneously in opposite directions; as and for the purpose set forth.

7. In avalve gear for steam engines a valve stem, a valve mechanism loosely sleeved thereon, anarm rigidly secured to said stem, a dash pot carried by said arm, connections between said valve mechanism and dash pot comprising a pivoted latch, a pair of knockoff arms loosely sleeved upon said stem, having cam projections thereon for engaging and tripping said pivoted. latch and means for automatically rocking said arms upon said stem in opposite directions simultaneously; as and for the purpose set forth.

8. In a valve gear for steam engines a valve stem, a dash pot carrying arm rigidly secured thereto, a valve mechanism loosely sleeved on said stem, connections between said valve mechanism and arm comprising a pivoted latch, means for automatically tripping said latch comprising a pair of arms loosely sleeved on said stem, said arms having cam projections,means for yieldingly pressing said latch into position to be engaged by said cam projections, and means for automatically rocking said arms simultaneously in opposite directions; as and for the purpose set forth.

9. In a valve gear for steam enginesa valve pivoted pin and carrying a secondary latch pivoted thereto, a pair of knock-0E arms sleeved around said valve stem and having cam projections, the cam projection on one side of said arms adapted to engage and trip said tripping latch during the first half of each stroke of the engine, the cam on the other of said arms adapted to engage said secondary latch and trip said. primary latch during the second half of each stroke of the engine,

a governor, and means actuated by said governor for rocking said arms simultaneously in opposite directions; asand for the purpose set forth.

1 1. In a valve gear for steam engines the combination of apivoted primary trip latch, a secondary trip latch pivoted to said primary trip latch to rock in a plane at right angles with the plane in which said primary latch rocks, a spring stop for said secondary latch, said secondary latch provided with a projecting.

toe, a pair of knock-off arms each having a cam, the cam on one of said arms adapted to engage said primary latch and trip the same during the first half of each stroke of the engine, the cam on the other of said arms adapted to engage saidsecondary trip latch to trip said primary latch during the second half of each stroke of the engine, means for operating said knock-off arms, as and for the purpose set forth.

12. In a valve gear for steam engines a stem, a valve mechanism sleeved to rock thereon, an arm rigidly secured to said valve stem, dash-pot securedto the outer end of said'arm, a trip latch carried by said valve mechanism adapted to engage and hold said dash pot whereby said arm and valve mechanism may rock in unison, a springfor normally retaining the engagement between said latch and dash-pot, means for adjusting the tension of said spring, a pair of-knock-oft arms sleeved on said valve stem carrying cam projections adapted to automatically disengage said trip latch on the dash pot, and means for operatstem, a valve mechanism loosely sleeved on said stem, comprising a hub and two arms,

one ofsaid arms being bored transversely, a.

pin rigidly held in one of said bores, a trip latch pivoted on said pin, a split bolt rotarily. adjusted in another of said bores, a spring carried in the split end of said pin'and' adapted to engage said trip latch and to be normally held in engagement therewith by said spring, rigid connections between said valve stem anddash pot, means for automatically tripping said tripping latch, as and for the purpose set forth.

l t. In a valve gear for steam engines a valve stem, a valve mechanism loosely sleeved there- 'on, comprising a hub and driving arm and a secondary arm, said secondary arm being transversely bored, a pivoted pin rigidly secured in one of said bores,a split pin carried in another of said bores and capable of rotary adjustment, a tripping latch pivoted on said pivoted pin, 'a spring carried in the split end of said adjustable pin and adapted to engage said tripping latch, a dash pot adapted to be engaged and held by said tripping latch, rigid connections between said dash pot and valve stem, a secondary latch carried by said tripping latch and spring stop therefor, a pair of knock-off arms loosely sleeved on said stem, each having a cam projection, one of said cam projections adapted during the forward stroke of the engine to engage said tripping latch, and the cam projection on the other of said arms adapted to engage said secondary latch whereby said tripping latch may be disengaged from said dash pot, a governor and connections between said governor and knock-off arms, whereby said "arms are rocked simultaneously in opposite directions; as and for the purpose set forth. 15. In a valve gear for steam engines the 1 combination of a pair of valve stems and valve mechanism, a dash pot for each stem, connections between said valve mechanism and dash pot whereby the same may be rocked in unison, means for tripping said connection, comprising a pair of knock-0E arms for each .valve stem, connect-ions between each knockoff arm on one stem and the corresponding knock-01f arm of the other stem, a governor, connections between said governor and one of said arms whereby the movement of one of said arms in one direction will effect a simultaneous movement of all the arms, as and for the purpose set forth.

16. In a'valve gear for steam engines a pair of valve stems, a valve mechanism loosely mounted upon each of said stems, a dash pot, rigid connections between said stems and dash pots, connections between said dash pots "and valve mechanism, whereby said dash pots, valve mechanism, and valve stems may be rocked in unison, means for .disengaging isaid connections comprising a pair of knockoif arms loosely sleeved on each'of said valve stems, a rod connecting each knock-oh" arm on one stem with the corresponding arm on the other stem, connections between said rods. a governor, connections between said governor-and one of said arms, whereby the rocking of one of said arms will simultaneously rock all the arms, the arms of each pair .be-

ing rocked in opposite directions, as and for the purpose set forth.

17. In a valve gear for steam engines a priniary trip latch in the form of a bell crank lever, a secondary latch pivoted to one arm of said lever, said secondary latch provided with a projecting toe, a spring stop for said secondary latch, a knock-0E arm having a cam projection, said cam projection being 10 provided with an inclined face, and means for operating saidknock-ofi arm, as and for the purpose set forth.

In witness whereof I have hereunto set my hand, this 15th day of May,1894, in the presthe presence of two subscribing witnesses.

DAVID A. DECROW. Witnesses: it

W. K. HELMERN, W. H. WELLS, J r.