US2282093A - Locomotive valve and valve gear - Google Patents

Description

May 5, 1942. H. J; SHERRILL LOCOMOTIVE VALVE AND VALVE GEAR F'iied Sept. -25, 1941 2 Sheets-Sheet 1 3nventor,

(Ittorneg Patented May 5, 1942 UNITED STATES PATENT OFFICE LOCOMOTIVE VALVE AND VALVE GEAR Harry J. Sherrill, Youngstown, Ohio Application September 25, 1941, Serial No. 412,234

' 6 Claims. (o1. 121-163) This invention relates to a locomotive valve and valve gear for operating the same and more particularly to an improved form of valve and valve gear wherein parts commonly associated with locomotive valve gear and valves are elimi- 1 nated and a simple, more eficient arrangement of operating means are provided.

The principal object of the invention is the provision of a locomotive valve and valve gear adapted to be used with reciprocable piston engines of the expansible fluid type wherein the gear and valve gear mechanism operates to retard the steam valve as soon as the steam is supplied to the main cylinder sufficiently to drive the piston by its expansive properties in one direction or the other, and accelerate the movement of the steam valve at the opposite ends of its movement during the movement of the valve from lead position to full steam port opening before reaching the cutoff position.

A further object of the invention is the provision of a valve gear mechanism adapted to eliminate the usual main cross-head and provide in place thereof a simpler, more efficient means of conveying the movement of the main connecting rod to the main piston rod of the engine, and at the same time incorporate with such mechanism means for varying the movement of the improved steam control Valve.

A still further object of the invention is the provision of a steam valve and valve gear mechanism of simple, sturdy construction comprisinga relatively few easily assembled parts.

The valve and valve gear shown and described herein comprises an improvement in the art over that shown in my Patent #2,255,902 issued September 16, 1941, wherein an auxiliary valve gear for locomotives incorporating means for varying the movement of the steam valve in a desirable manner is shown.

The present invention concerns the development of an improved steam valve and simplified valve gear for operating the same which valve gear includes means for eliminating the conventional cross-head of the steam engine as is commonly associated with the main connecting rod and main piston rod thereof.

With the foregoing and other objects in view which will appear as the description proceeds, the invention resides in the combination and arrangement of parts and in the detail of construction hereinafter described and claimed, it being understood that changes in the precise embodiment of the invention herein disclosed, can be made within the scope of what is claimed without departing from the spirit of the invention.

The invention is illustrated in the accompanying drawings, wherein:

Figure l is a side elevation with parts broken away showing the valve gear arrangement, the steam valve and main cylinder, and illustrates the valve gear mechanism in back center position.

Figure 2 is a cross-sectional side elevation of the improved steam Valve used in connection with the improved valve gear shown in Figure 1. Parts of the mechanism shown in Figure 2 are broken away.

By referring to the drawings in Figure 1 in particular, it will be seen that the illustrated embodiment of the invention shows a valve gear which imparts reciprocable movement to an improved steam admission and exhaust valve of an engine and only sumcient illustration is given to enable those skilled in this art to readily understand the invention. The valve gear mechanism shown herein can be used in combination with any well-known valve gear and the Baker valve gear is shown wherein a bell crank I0 is provided with a horizontal arm II which arm ll drives its movement through a system of links and levers from an eccentric pin I2 of a driven wheel l3 of a locomotive. A valve rod I4 is pivoted to the lower end of the vertical arm of the bell crank I0 and from that point inclines forwardly and upwardly, the forward end being split and pivotly mounted upon a pin I5. Pivoted to the forward end of the valve rod I4 is the upper end of a vertically disposed combination lever It. Pivotly connected to the lower end of the combination lever I6 there is a union link H, the other end of which is adjustably pivoted to a crank arm I8 of a crank shaft I9 which is rotatably mounted in an inclined pivot rod 20 which rod 20 is in turn pivoted to a fixed pivot 2| which in turn is carried by a structural portion of the locomotive. Positioned below the mechanism just described and in aposition commonly occupied by the cross-head of a steam engine there is an inverted T-shaped bracket 22 to which is pivoted, by means of pin 23, a main connecting rod 24 of the engine and to which bracket is also affixed a main piston rod 25 of the engine, which piston rod is positioned on a horizontal plane and connected to the main piston of the engine.

In order that this T-shaped bracket 22 will support and maintain the pivot point 23 between the connecting rod 24 and the piston rod 25 in proper alignment a cross-piece 26 is pivoted at a point 2'! centrally thereof at the uppermost portion of the inverted T-shaped bracket 22 and the outermost ends of the cross-piece 26 are in turn pivoted to the lower end of the pivot rod 20 by means of a pivot 28 and to the upper end of a secondary pivot rod 29 by means of a pivot 3|]. The secondary pivot rod 29 is positioned at an angle opposite to that of the pivot rod 20 and inclines downwardly and forwardly from the pivot point 33. Its lowermost end is pivotly afiixed, by means of a pivot 3|, to a structural portion of the locomotive which structural portion is indicated in the drawings by the numeral 32.

It will thus be seen that the cross-piece I26 and the inverted T-shaped bracket 22 pivoted to a central point thereon, are supported and maintained by the two pivot rods 23 and 29 in a manner so that horizontal movement of the T-shaped bracket 22, as in response to the movement of the piston rod 25 and the connecting rod 24, will cause the cross-piece 23 to move toward the main cylinder 33 of the engine and at the same time tilt as it follows the respective arcs of the pivot rods 23 and 23, the center point of the crosspiece 23 which comprises the pivot 21 will, however, follow an even horizontal course and support and maintain the connecting rod 24 and piston rod 25 and their connecting bracket 22 in a satisfactory manner thus replacing and eliminating the usual cross-head construction used for this purpose, and at the same time providing a portion of the valve gear mechanism necessary for imparting desirable movement to a steam valve 34. i

In orderthat the crank shaft l3, carrying the crank arm i8 to which the union link I! is connected, may be rotated, a pinion gear 35 is positioned on the crank shaft l9 and positioned adjacent thereto, upon a structural portion 36 of the locomotive frame, there is a stationary rack 31 formed with the plurality of gear teeth thereon adapted to mesh with and revolve the pinion gear 33 at such times as the pivot rod 2|) swings through its normal arc in supporting and maintaining the cross-piece 26 and bracket 22 in position as heretofore described. The rack 31 is mounted on the structural portion 36 of the locomotive by any suitable means and it will thus be seen that when the locomotive wheel t3 revolves in the direction indicated, the system of links and levers connecting the eccentric pin I2 and the pin l of the combination lever l6 serves to impart controllable motion to the upper end of the combination lever l6 while the lower end thereof receives movement from the main pivot M on the locomotive wheel through the connecting rod 24, the bracket 22, the crosspiece 26, the pivot rod 23, the pinion gear 35, and its crank shaft i9 and crank arm I8 and the union link I! connected thereto thus imparting movement to the lower end of the combination lever Having thus described that portion of this invention relating to the valve gear mechanism adapted to impart a desirable movement to the improved steam valve, the following description concerns the improved steam valve and reference will be made-therein to the actuating portions of the valve gear mechanism in order that the interdependency of the Valve gear mechanism and steam valve may be seen.

By referring to Figure 2 of the drawings wherein an enlarged cross-sectional elevation of the steam valve 34, illustrated in connection seat 4|.

with the valve gear shown in Figure 1, may be seen, wherein the usual valve chamber 34 provided, as normally, with removable end portions 38, has been fitted with a tubular member 39 which tubular member 39 extends the full length of the valve chamber 34 and which tubular member carries upon its innermost surface a plurality of annular valve seats 40 and a plurality of disk valve seats 4| which disk valve seats 4| are positioned centrally within the tubular member 39 by means of a plurality of spacing members 42 and which disks 4| are positioned one on each side of a pair of steam ports 43 which ports are formed in the tubular member and which ports register with steam ports and steam connections 44 leading from the valve chamber 34 to the main cylinder 33, which main cylinder and ports comprising the passageways thereof are of conventional design.

In order that steam entering the valve chamber and the tubular member 39 therein as by Way of a steam port 45 which connects with the main boiler of the engine (not shown) may be controlled in entering the steam ports 43 and 44, a pair of oppositely disposed cylindrical shaped valves 46 are positioned in the central section of the tubular member 39 and adapted to seat against both the annular valve seats 40 and the disk valve seats 4| simultaneously. In Figure 2, the left hand portion of the Valve chamber 34 is shown in cross-sectional detail it being understood that the right hand portion thereof contains a duplicate assembly of valves with the exception that the same are in reversed position in relation to those shown in the left hand portion of the illustration.

The cylindrical shaped valve 46, which is one of a pair, is provided with an enlarged shoulder having an annular seat 47 thereon adapted to engage the annular valve seat 40 immediately adjacent thereto. The end of the cylindrical valve 43 closest the disk valve seat 4| is slightly enlarged as illustrated and the end section is adapted to seat tightly against the disk valve The cylindrical valve 46 is supported and maintained in a slideable manner upon a horizontally positioned rod 48, which rod 48 is positioned between and supported by the disk valve seat members 4|, by means of spiders 49, and it will be observed that a coil spring 50 is positioned centrally within the tubular member 39 adjacent the steam admission port 45 and about the horizontal rod 48 and that one of its ends engage one of the spiders 49 of the cylindrical shaped valve 46 while its other end is adapted to engage the other one of the pair of cylindrical valves 43 in a similar manner so that the normal tendency of the pair of cylindrical valves 43 is to remain closed so that steam admitted to the tubular member 39 through the steam admission port 45 can not pass the valves and can not, therefore, enter the steam ports 43 and 44 until the valves are opened.

It is obvious that the exhaust port valves are necessary so that the main piston traveling in the main cylinder may exhaust the steam ahead of it in the return stroke and it will be seen that lar shoulder is indicated by the numeral 53 and is adapted to seat against one of the annular valve seats 43 shown adjacent thereto. The end portion of the cylindrical valve 52 is adapted to seat against the disk valve seat 4| immediately adjacent thereto.

As it is desirable that the cylindrical valve 52 will normally remain closed, a coil spring 54 is positioned between one of a pair of spiders 55 in the cylindrical valve and the end portion 38 of the valve chamber. It will be seen that the cylindrical exhaust valve 52, which is one of a pair, is maintained in position by being slideably mounted upon a horizontal rod 48A which rod 48A is positioned between and supported by the end portion 38 and the disk valve seat 4|, be tween which members the exhaust valve 52 is located.

In order that these cylindrical steam and exhaust valves 46 and 52 may be controlled and caused to open alternately, each is provided with a lever 45A and 52A, respectively, which levers are of approximate U-shape the arms of which are afiixed to the valves 46 and 52 and which levers are positioned on the opposite sides of the disk valve seats M with respect to the respective valves to which the levers are affixed. The arms of the levers 46A and 52A thus pass between the spoke-like members 42 and the levers are adapted to alternately receive movement from a cam 55 which is positioned between them. The cam 56 is positioned by means of shaft 51 which in turn is positioned transversely of the valve chamber 34 and which shaft is provided at its outermost end with a crank 58 as may be seen by referring to Figure l of the drawings. The cranks 58, one for each of the pair of cams necessary to operate the cylindrical valves, are

coupled to the valve gear mechanism as illustrated in Figure 1 by means of a valve connection rod 53 which in turn is pivoted to the combination lever H at a point 60 thereon and which valve connection rod is supported by means of .a pivoted supporting hanger 61. Thus movement of the valve gear as heretofore described imparted to the combination lever 16 is conveyed by means of the valve connecting rod 59 to the cranks 58 on the shafts 5'! which are positioned transversely of the valve chamber 34 and thus the movement is conveyed to the cams 56 which cams serve to impart movement alternately to the levers 45A and 52A, and thus open and close the steam and exhaust valves 46 and 52 connected thereto.

In order that the steam valve and the exhaust valves as heretofore described may be opened quickly, projections 62 and 62A are formed upon the levers 45A and 52A respectively, so that the maximum opening of the valve is obtained immediately upon the first movement of the cam 56, the projections 52 and 62A being of a form that offsets further movement of the valve levers 46A and 52A during the remainder of the movement of the cam 56, thus both the valve arrangement and the valve gear arrangement comprise means for effecting the quick opening of the steam valve followed by a quick cutoff and a long dwell. This action is particularly desirable -ior the emcient operation of a steam engine as the heretofore slow conventional valve opens slowly, cuts off slowly, and passes through a uniform dwell period.

It will thus be seen that the valve gear illustrated in Figure 1 and particularly the pinion gear and the rack 31 serve to impart such desirable movement to the improved steam valve. It will be seen that clockwise revolving motion of the pinion gear 35 resulting from its engagement with the rack 31 will result in the crank l8 traveling through in succession four quarters of complete revolution. As the crank passes through the first quarter of revolution its movement, as a result of the engagement of the pinion gear 35 with the rack 31, will be to speed up the motion of the combination lever l5, through the connecting union link ll, in comparison to the speed of the pivot lever 20. When the crank I 8 reaches a horizontal position extending toward the combination lever IS, the motion imparted thereby to the combination lever l 6, through the union link I1, will momentarily be the same as that of the pivot lever .20 as the crank l8 swings downwardly through the second quarter of revolution, to assume an approximately perpendicular position. It will be observed that the motion is greatly retarded as the crank I8 is traveling in an opposite direction to that of the pivot lever 20 and that when the crank l8 reaches the lowermost position and correspondent in alignment with the pivot lever 20 the relative movement of the combination lever IE will have almost ceased with respect to the pivot lever 23. As the crank 18 subsequently swings upwardly into the third successive quarter of clockwise revolution the motion imparted the combination lever I6 is still greatly retarded by increasing gradually until the crank reaches a horizontal position extending away from the link I! passing this point the crank 18 lies vertically through the fourth quarter of clockwise movement during which time the motion imparted the combination lever i6 is again accelerated as the crank 18 is now overtaking the pivot lever 20 and thus causing acceleration of the valve gear. The reverse occurs when the movement is reversed by the movement of the pinion gear 35 in the opposite direction along the rack 31 as the pivot lever 20 returns to the position indicated in Figure 1 of the drawings.

This variation of the conventional movement imparted to a steam valve by conventional valve gear is further utilized to great advantage by the improved steam valve mechanism herein disclosed as the cams 56 therein are shaped so as to impart the desirable motion to the valve 45 and 52 which action may obviously be varied by the cams used and which action continues in eilect the desirable variation of valve movement originated and imparted to the cams 55 by the improved valve gear.

Having thus described my invention, what I claim is:

1. A steam control mechanism for a steam engine having a driven rotatable member, and a driven reciprocable member, comprising steam admission and exhaust valves and a combination lever adapted to impart movement to the same and deriving motion at its lower end portion from said reciprocable member and its upper end from the said rotatable member, a reciprocable pivotly supported bracket for supporting said reciprocable member, means providing a connection between the said pivotly supported bracket and the lower end portion of the said combination lever, said means including a pinion gear adapted to engage a stationary rack, a crank rotated by said pinion gear and means connecting the said crank to the said lower end of the combination lever, together with two pairs of oppositely disposed poppet valves actuated by the movement of the said combination lever.

2. A steam control mechanism for a steam engine having a driven rotatable member and a driven reciprocable member, and comprising steam admission and exhaust valves and means for actuating the same, the said valves comprising two pairs of oppositely disposed poppet Valves each of which is slideably supported and adapted to seat against two valve seats, cams positioned one between each of the pairs of poppet valves and adapted to open and close the same alternately, a combination lever adapted to impart movement to the said cams, a reciprocable pivotly supported bracket for supporting the said reciprocable member, means forming a connection between the said pivotly supported bracket and the lower end portion of the said combination lever, said means including a pinion gear adapted to engage a stationary rack, a crank formed on said pinion gear and connected to the lower end of the said combination lever so that conventional movement of the said reciprocable member is at first accelerated and then retarded and subse-' quently accelerated again by the said pinion gear before being imparted to the lower end of the said combination lever.

3. A valve gear mechanism for steam engines having a driven rotatable member, a driven reciprocabl member, and a steam admission and eX- haust valve, and comprising a combination lever deriving motion at its lower end portion from said reciprocable member and at its upper end portion from said rotatable member, means replacing a conventional cross-head for supporting the said reciprocable member, said means comprising a supporting bracket pivotly affixed to the said reciprocable member and a pair of pivot rods pivoted to a portion of the said supporting bracket and to structural parts of the steam engine at their upper and lower-most ends respectively, together with means for conveying the movement of one of the said pivot rods to the lower end of the said combination lever.

4. A valve gear mechanism for steam engines having a driven rotatable member, a driven reciprocable member, and a steam admission and exhaust valve, and comprising a combination lever deriving motion at its lower end portion from said reciprocable member and at its upper end portion from said rotatable member, means replacing a conventional cross-head for supporting the said reciprocable member, said means comprising a supporting bracket pivotly aflixed to the said reciprocable member and a pair of pivot rods pivoted to a portion of the said supporting bracket and to structural parts of the steam engine at their upper and lower-most ends respectively, together with means for conveying the movement of one of the said pivot rods to the lower end of the said combination lever, said means including a pinion gear on one of the said pivot rods engaging a rack, and a link connection between a point on the pinion gear and the lower end of the combination lever, said means adapted to modify the movement imparted to the said combination lever.

5. A valve gear mechanism for steam engines having a driven rotatable member, a driven reciprocable member, and a steam admission and exhaust valve, and comprising means for supporting the said reciprocable member and means for imparting a desirable movement to the said steam admission and exhaust valve, said means comprising a pair of pivot rods pivoted at their upper and lower ends respectively to structural portions of the said steam engine and at their innermost ends to a movable portion of a supporting bracket, the uppermost one of the said pivot rods inclining forwardly and upwardly from the said bracket and the lower-most one of the said pivot rods inclining forwardly and downwardly from the said bracket when the said reciprocable member is in back center position; the said supporting bracket adapted to move on a horizontal plane and be supported by the said pivot rods, together with a combination lever deriving motion at its upper end portion from the said rotatable member and at its lower end portion from one of the said rods.

6. A valve gear mechanism for steam engines having a driven rotatable member, a driven reciprocable member, and a steam admission and exhaust valve, and comprising means for supporting the said reciprocable member and means for imparting a desirable movement to the said steam admission and exhaust valve, said means comprising a pair of pivot rods pivoted at their upper and lower ends respectively to structural portions of the said steam engine and at their innermost ends to a movable portion of a supporting bracket, the uppermost one of the said pivot rods inclining forwardly and upwardly from the said bracket and the lower-most one of the said pivot rods inclining forwardly and downwardly from the said bracket when the said reciprocable member is in back center position, the said supporting bracket adapted to move on a horizontal plane and be supported by the said pivot rods, together with a combination lever deriving motion at its upper end portion from the said rotatable member and at its lower end portion from one of the said rods, a pinion gear mounted on one of the pivot rods and engaging a stationary rack providing the connection between the said lower end of the combination lever and the said pivot rod, said mechanism adapted to impart a modified movement to the said combination lever with respect to the movement of the reoiprocable member.

HARRY J. SHERRILL.

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