US2518024A - Locomotive steam controlling system - Google Patents

Description

Aug. 8, 1950 J. KIRCHHOF 2,518,024

' LOCOMOTIVE STEAM CONTROLLING SYSTEM Filed June 1, 1944 5 Sheets-Sheet 1 Aug. 8, 1950 Filed June 1, 1944 5 Sheets-Sheet 2 ATTORNEYS 8, 1950 J. KIRCHHOF 2,518,024

LOCOMOTIVE STEAM CONTROLLING SYSTEM Filed June 1, 1944 5 Sheets-Sheet 3 lNV NTOR- ill? A TT RNEYS Aug. 8, 1950v J. KIRCHHQF 2,518,024

LOCOMOTIVE STEAM CONTRQLLING SYSTEM Filed June 1, 1944 5 Sheets-Sheet 5 EXHAUST CAM FORWARD INTAKE CAM FORWARD EXHAUST (AM 67 REVER$E INTAKE CAM lNV TOR B W mamas Patented Aug. 8, 1950 LOCOMOTIVE STE AM CONTROLLING T M SYS E Julius Kirchhof, Ruxton, Md., assignor, by mesne assignments, to Franklin Railway Supply Company, New York, N. Y., a corporation of Delaware Application June 1, 1944, Serial No. 538,230

7 Claims. 105 -48) This invention .relates to locomotive steam controlling systems and is especially concerned with the structure and operation of, and the control means for, the cam mechanism utilized in the actuation and timing (including reversal) of the valve means for the locomotive engine.

Although features of the invention may be used in other types of engines, or engines having other types of cylinders, pistons and valves, the invention is particularly useful in a reversible locomotive engine having a plurality of cylinders with double-acting reciprocating pistons, operated by steam which is controlled by separate admission and exhaust double-beat poppet valves at each end of each cylinder; and it is in such an association that the present preferred embodiment of the invention is herein illustrated and described.

Among the primary objects of the invention are: the simplification, and the rendering, more reliable, of engine valve gear, and of the reverse gear therefor; the closer coordination of valve gear and reverse gear elements, and preferably the substantial unification thereof into, one compact mechanism; the securing of such results with a minimum of materials and of weight; the

reduction of costs of manufacture, maintenance and repair; and reduction of the engineers burden in controlling the direction of operation and the power output of the locomotive.

, The invention further contemplates the effectuation of one or more of the above general purposes by a mechanism which, while havinga minimum number of adjusted operating positions, produces a variety of efiectiveoperating results,

"dependent upon the speed of the engine; and more specifically the invention accomplishes this by the provision of a valve-actuating cammeans,

configured with a stepped profile (or the equivalent) adapted to cause diiferent effective cut-offs 'at different R. P. M. of the engine, without the ing the stepped profile above mentioned, is so positioned when in operation that its entire efiective profile is progressively operative upon its actuated valve means in each cycle of the engine;

and, in the case, of a reversible engine (such as a locomotive) the provision of another similar cam means for reverse operation, an'd'the use of selector means for putting either of said cam means into effective operation.

Since the point of cut-off of the steam supply to the cylinder is, among the several valve events,

. the effective exhaust valve operation should also vary with variation in speed, and the invention therefore also provides for securing a plurality of effective compression points (at different speeds) for a given setting of the control.

Still further, the invention contemplates securing these results in both forward and reverse operation, and in this regard the invention '(though illustrated herein as applied to a road locomotive) is of especial value in the case of switching engines. Indeed, though the range and fineness of graduation of cut-off, and other valve events, need not be so all-inclusive in switching service as in road service, the capabilities of the engine in switching service should be about equal in forward and reverse operation, which is hardly a requisite in road service. The present invention is particularly suited to securing this combination of characteristics, 1. e. it secures a relatively limited number of different effective valve operations, in both forward and reverse, with only a 2-position adjustmentone for forward operation and the other for reverse-although a non-operating or neutral position is also provided'. Atthe same time the'invention also enables exceptionally rapid and easy shifting between forward and reverse operation, which is a characteristic of especial benefit in switchin service. 3

The invention also contemplates what may be termed a drifting setting of the valves, when the reverse lever is in its neutral, setting.

The invention further involves a combining of the valve gear and the reverse gear into a unitary structure, except for the control, which latter in the preferred embodiment comprises a valve and valve handle, adapted to be mounted as a separate unit in the cab, from which fluid pressure connections are taken to the valve gear and reverse gear unit; and the invention further takes advantage of this arrangement to utilize the fluid pressure system not only as part of the control but also as a power means for adjusting the mechanism.

How the foregoing objects and advantages, to-

3 gether with such others as may occur to those skilled in the art, are secured by my invention, will appear from the following description, taken together with the accompanying drawings, wherein:

Figure 1 is a fragmentary, and partially diagrammatic side elevational view of a locomotive embodying the steam controlling system of the present invention;

Figure 2 is an enlarged section taken through the unitary valve gear and reverse gear of the present invention, taken approximately on the line 22 of Figure l, and showing (in elevation) in association therewith the control valve, which would normally be located in the locomotive cab, rather than as shown in Figure 1 or in Figure 2;

Figure 3 is a section at right angles to Figure 2, through the mechanism of said figure and also through the admission valves in the valve chests at the ends of the locomotive cylinder, the upper portion of the cylinder being also fragmentarily illustrated; I

Figure 4 is a fragmentary plan section taken through the left-hand admission valve of Figure 3, and the exhaust valve at the same end of the cylinder, said two valves being located in side-byside relation;

Figure 5 is a grouping on one plane of the four cams which are mounted serially on the cam shaft shown in Figures 2 and 3, this figure illustrating their relative angular positions when the righthand piston and crank of the engine are as shown in Figure 1;

Figure 6 is a side elevational view of the control valve and its handle, set in neutral position;

Figure '7 is a section on the line of Figure 6;

Figure 8 is a section on the line 3-8 of Figure 7, but omitting certain parts such as the seating spring and the operating connection between the valve handle and the valve; and

Figure 9 is a schematic View showing the effective valve events secured by one of the admission cams.

Referring to Figure 1, the forward end portion of the locomotive boiler appears at driving wheels beingshown in outline at |2. In the embodiment illustrated it is assumed that the engine is of the two-cylinder type, the right-hand cylinder being shown at I6, having a piston therein, with a piston rod l8 projecting rearwardly, with its crosshead |9 associated with the crosshead guide 20. The crosshead i9 is adapted to be coupled with the main crank pin 2| of one of the drivers by means of the main rod (not shown) the center line of which is indicated by thedotand-dash line 22.

Valve chests 23 and 24 are arranged adjacent the front and rear ends of cylinder IS, the steam supply to these chests including the steam pipe 25 and branches 26-26. Exhaust passages (one of which is shown fragmentarily at 64 in Fig. 4) are extended from the chests inwardly and thence upwardly into the smoke-box in a known manner which need not be considered in detail herein.

As hereinabove indicated, the invention contemplates the employment of poppet type steam admission and exhaust valves, these valves being arranged within the steam chests 23 and 24 and being adapted to be operated by the intervening cam actuating mechanism which is desirably housed within a cam box 27 mounted at the top of the cylinder between the front and rear steam chests and secured in position by means of wedge fastening devices 21a. In the preferred embodiment herein illustrated, the valve actuating mechanism comprises a plurality of rotative-type cams mounted in the cam box and adapted to be driven by a drive transmission extended forwardly to the cam box from the driving wheel l2 with which the main rod is associated. This drive transmission includes a return crank 28 mounted on the crank pin 2| laterally outside of the plane of the main rod. A gear box 29 is associated with the free end of the return crank 28, this gear box serving to house a pair of intermeshing gears, one of which is fixed to and rotative with the return crank and thus with the driving wheel about an axis coinciding with the axis of the driving wheel axle, the other gear being secured to shaft 30 which in turn is coupled with the forwardly extending drive shaft 3| by means of a universal joint 32. At the forward end of shaft 3| another universal 33 serves to couple the drive shaft with another shaft 34 which projects from an extension 35 of the cam box for housing additional transmission gearing described more fully hereinafter with reference to Figure 2. The gear box 29 is non-rotative but movable with the return crank and thus with the driving wheel, the box being restrained as against rotation by means of a link 36 which is pivoted at 31 to a bracket 38 formed as a part of the gear box, the other end of the link being pivoted at 39 to a fixed bracket 40 adapted to be mounted on any suitable part of the locomotive structure, such as the boiler H or one of the main frame members 4|. The main frame members are provided with the usual pedestal jaws in which the driving axles are given freedom for limited vertical movement. The pivoted link 36 not only restrains the gear box 29 as against rotation but also serves to accommodate the vertical movement of the gear box with the driving wheel.

Control of the cam actuating mechanism for the valves in the steam chests is provided for by a power amplifying reversing mechanism generally designated by numeral 42 which, as hereinabove indicated, preferably is intimately associated with the cam actuating mechanism itself, to comprise a unified structure therewith. Actuation of the reversing mechanism is effected by an enginemans control lever 43 which serves to actuate valve device 44 having fluid pressure connections 45 and 46 extended forwardly for connection with the reversing mechanism 42. Although the control lever 43 and valve 44 are illustrated in Figure 1 at the side of the locomotive boiler, it is to be understood that these control elements would normally be located in the cab of the locomotive for convenient access by the engineer.

The arrangement of the poppet valves, steam passages and cam actuating mechanism is indicated in Figures 2, 3 and 4. In Figure 3 the upper portion of the right-hand cylinder is indicated at IS, the cylinder having ports 41 and 48 at the front and rear ends thereof, which ports extend upwardly into the valve chests 23 and 24. At the front end, the port 41 has two diverging portions 49 and 50 which extend, respectively, to the admission and exhaust valves at that end of thecylinder. Similarly, the rear end port 48 has admission and exhaust branches 5| and 52 associated respectively with the admission and exhaust valves at the rear end. The plane of the sectional view of Figure 3 contains the axes of the admission valves, at the two ends, the front admission valve being shown at 53 and the rear admission valve at 54. The front and rear live steam chambers 55 and 56 are adapted to' be connected through passages 5! and 58 with the steampipebranches 25 (see Fig. 1-).

The two admission valves are counterparts, each being of the double-beat type having a body portion- 59 carried by a hub 60 which is mounted on a'valve stem 61, the valve being urged toward closed position by spring 62. The inner end portions' 6-l-a and Nb of the valve stems of the front andrear admission valves project into the space betw'eenthe steam chests, for cooperation with the intervening cam actuating mechanism described hereinafter.

As plainly shown in Figure 3, valves 53 and 54 serve to control theadmission of steam from the chambers 55 and 56 through the ports 41 and 48 toopposite ends of the cylinder 15; One of these admission valves, i. e. the admission valve at the rear end of the cylinder (valve 54) also appears in Figure 4, which view further shows the rear end exhaust valve 63 which is operatively interposed between the branch 52 of the cylinder port and the exhaust steam passage 64. In the preferred embodiment here shown, the exhaust valves also have the same size, structure and arrangement as the admission valves, which is of advantage from the standpoint of reduction in manufacturing costs, upkeep, replacement of parts, etc. It may here be mentioned that employment of a standardized form of valves is facilitated by virtue of the configuration of the cylinder ports including the diverging portions =35 and 50 (at the front end of the cylinder), and 5| and 52 thereof (at the rear end of the cylinder).

As with the admission valve stems, the stems of the exhaust valves also project inwardly from the valve chests for cooperation with. the intervening cam actuating mechanism, the projecting end of one of the exhaust valve stems being shown at 6 In in Figure 4.

The arrangement of the cam actuating mechanism is best shown in Figures 2 and 3. As there seen, a cam shaft 65 is mounted in the cam box 21 for rotational movement and also for axialadjustment to different positions. The cam shaft carries cams and bearings serially mounted thereon, including the following parts (best seen in Figure 2): A head 66 is'arranged at'the left end, and adjacent thereto the admission cam Bl for reverse operation, next to which is collar 58, and then the admission cam 69 for forward operation. In thecentral portion of the shaft appear bearing liners 10-10, and then follow the exhaust cam H for reverse operation, collar 12, and exhaust cam 13 for forward operation. At the extreme right end, as viewed in Figure 2, is another head 14,. all of these parts being clamped together on the cam shaft by means of the nuts 15-15 which are threaded onto the ends of the camshaft. I

The head 66 is provided with a splined connection with sleeve 15 as indicated at 16a. The sleeve 15 is rotatable in bearings 11 and 18, the sleeve having a worm wheel 19 formed thereon, which worm wheel cooperates with worm 80 which is secured to shaft 34 of the drive transmission above described. Worm 80 is housed within the extension 35 of the cam box as mentioned above in connection with Figure 1.

The head 14 at the opposite end of the cam shaft is slidably and rotatably mounted in bearing sleeveBl A non-rotative bearing block 82 in the central region of the cam shaft servesrto support-;the:bearing liner=l0-'l0, the bearing block 82 being slidablein a, -parti-cylindrical sleeve 826.

which sleeve is slotted along the upper side there of to accommodate the shifter fork 83 the prongs of which engage in external grooves formed; the block 82, v The upper side portions of the s1eeve82a are cut out in the central regionas in dicated at 321) to permit insertion of the shifter fork into the grooves in bearing block 82, when assembling the parts. The sleeve 82a is mountedin the cam-box by means of integral webs and 85' lying in transverse planes. The mechanism for controllably shifting the axial position of the cam shaft includes a pair offlu-id pressure cylinders 86 and 81 in which pistons 88 and 89 arearranged, the pistons having stems 90 and 9! which may comprise the end portions of a rod extended through and secured in the part 92 of the shifter fork 83. Fluid pres-v sure connections 45' and 46, mentioned abovein' the description of Figure I, are respectively coupled with cylinders 86 and 81 and serve to admit actuating fluid to and to exhaust fluid from the cylinders 85 and 81 in order to move the shifter fork in one direction or the other. The connections 45 and 46 are under the control ofvalve 44 described more fully hereinafter with refer ence to Figures 6, 7 and 8. 1

Plungers 93 and 94 which are adapted to be advanced by springs 95 and 96, cooperate with an upwardly projecting finger 9! which is rigid with the shifter fork and thereby actto center the fork and also the cam shaft in a mid position. The action of these parts in effecting adjustment of the axial'position of the cam shaft is considcred'more fully below.

' Referring now to Figure 3, as there shown in termediate or cam follower levers 518 and 99 are pivotally mounted at Hi0 and NH adjacent the bottom of the cam box 21, the levers havingcam follower rollers l lib-I03 and the free ends of the levers being extended upwardly to engage the inner ends of tappets 1'04 and I05 which cooperate respectively with the projecting ends Bid and 61b of the front and rear-admission valve stems.- The cam rollers [02 and I53, as shown, both cooperate with the admission cams, the=cam shown in- Figure'3 being the admission cam for forward oper--- ation.

A similar arrangement of intermediate levers is employed in association with the cams'fland 13 for the exhaust valves, one such intermediate lever being indicated at I96 in Figure 2.

From the above it will be apparent that in the arrangement described one cam (69) serves to control the two admission valves at opposite ends of the cylinder during forward operation of the locomotive, another cam (61) servin this purpose dur-ing reverse operation. Similarly; exhaust cam 13 actuates both exhaust valves duringffor-Ward operation, and cam ll actuates both exhaust valves during reverse operation.

' Turning now to Figures 6, 7 and 8 which illustrate the engineers control for the reversing mechanism described above in connection with Figure 2, the control valve 44 includes a casing l5! which is closed at one end by a valve seat member Hi8 having an exhaust port I09 and a pair of oppositely disposed ports ill] and Hi, the exhaust port being adapted to discharge fluid under pressure to atmosphere and the ports H 0 and [H being connected respectively with pipes 45 and 46. Within the casing ill! a rotative valve H2 is urged against the cooperating member I08 by a spring H3. The valve H2 is adapted to be rotated by a flattened log I it formed on] a short shaft I I which in turn is adapted to be adjusted by the engineers control lever 43.

Fluid under pressure (derived from any suitable source on the locomotive such, for instance, as the air brake reservoir) is supplied to the control valve through connection II6 which introduces the pressure fluid to the interior of the casing IBI. Pressure may be delivered from the interior of easing IIII through one or the other of a pair of ports I I! and I I8 formed in the valve II2, which ports are so positioned as to register, respectively, with ports H9 and III which are coupled with the pipes 45 and 46. When pressure fluid is supplied to either of ports H0 and III, the arcuate cavity H9 in the valve connects the other port with the exhaust passage I09. Limiting stops I20 and IZI define forward and reverse positions for the control lever 43 which are indicated, respectively, at 43 and 431.

vFrom Figure 2 it will be seen that there i a mid position of the engineers control lever, indicated at 43m. In the mid position (the full-line position in Figure 6), the arcuate cavity H9 of the valve connects both of ports I III and I I I with the exhaust I09, and in this position, therefore, fluid is exhausted from both of the power cylinders 86 and 81 (see Figure 2), whereupon the springs 95 and 9B, acting through plungers 93 and 94, center the cam shaft in its mid position.

In connection with the operation of the control mechanism above described, attention is called to the fact that the engineers control lever need be moved to only one running position for each direction of operation of the locomotive. In the mid position the cam rollers of the admission and exhaust valves ride on the collars 68 and I2, respectively, of the cam assemblies. In accordance with the preferred embodiment, the surface of collar 68 is arranged to leave both of the admission valves closed throughout the entire cycle of engine rotation. On the other hand, the collar I2, for the exhaust valves, has a somewhat larger diameter, such as to maintain both of the exhaust valves partially open throughout the entire cycle. This mid position serves for drifting purposes, at which time it is desirable to open a communication between the two ends of the cylinder through the exhaust passages, so as to avoid the development of vacuum conditions in either end of the cylinder.

Although various features of the above-described cam actuating mechanism and reversing mechanism are applicable to cams of a variety of types, nevertheless many features of the structure are of especial utility and advantage when employed in association with cams of the rotating type, particularly where cam profiles are utilized in accordance with the showing of Figures 5 and 9. Moreover, in connection with the following discussion of the cams themselves it should be kept in mind that various features of the cams are of utility and advantage when employed in association with actuating and control mechanisms of types other than that described above.

Referring first to Figure 5, the four earns 61, 69, I I and I3 described above in connection with Figure 2, are here shown in profile in the angular positions which they assume with the cam shaft in the position of Figure 2. Note that the keyways I22 of the several cams as shown in Figure 5 are all located at the bottom, these keyways being adapted to cooperate with keys I23 and I24 (shown in Figure 2) for the admission and exhaust cams, respectively. This position of the.

cams corresponds approximately to the lowermost position of the crank pin and the mid stroke position of the piston. The admission cam 69 for forward operation is also shown in Figure 9 in association with the intermediate lever and valve actuated thereby, the position of the cam 69 in Figure 9 being 90 from the position shown in the other figures. Specifically, the cam 69 in Figure 9 is at that position corresponding to forward dead center, which is slightly after the admission point, i. e. the point at which the valve 54 commences its opening movement so as to admit steam to the cylinder.

The direction of rotation of cam 69 is indicated by the arrow R in Figure 9, and from examination of this figure it will be seen that the cam lobe I25 has just commenced to swing the intermediate lever so as to open the associated admission valve. The maximum-lift portion of lobe I25 is centered on point A, and beyond this portion of the cam are additional surfaces B and C which are successively of lower effective heights. The advance edge of surface B is indicated at b, and the advance edge of the still lower cam surface C is indicated at 0. Finally, at point 11 the cam radius is reduced to the value at which the associated valve will remain closed until the advance edge of lobe I25 is again brought adjacent the follower roller I03.

The effect of the foregoing camprofile is to provide for opening of the admission valve to different degrees of opening when the cam roller I63 engages respectively the several portions A, B, andC of the cam. The angular dimension of lobe I25 is such as to provide full valve opening, with partial but considerable closure occurring at about 50% of the piston stroke when the roller reaches point I). The following portion B of the cam retains the valve partially open for an additional portion of the stroke, for example from 50% to 65% of the stroke, at which time the roller reaches point e, and here again the valve is caused to move further toward closed position, though still being slightly cracked open while theroller rides on surface C. This condition is maintained, say for a further 20% of the stroke, i. e. up to until the point (2 is reached, whereupon the valve is completely closed and remains closed until the point of preadmission, which occurs when the advance side of the lobe I25 reengages the cam roller.

Because of the above-describd cam profile, different effective cut-offs are provided at different operating speeds of the locomotive. Thus, at very low-speed operation or at start, the effective cutoff (in the specific example given above) will occur at 85% of the piston stroke, since, at start or at very low speed, even a very small valve opening is adequate toadmit the starting steam. As the speed of the engine increases, wire drawing occurs in the portion of the stroke corresponding to portion 0 of the 0am, since at this time the valve opening is very small and insufficient to pass the volume of steam required to provide 85% effective cut-off. Similarly, at still higher speed, wire drawing will even occur in the portion of the stroke corresponding to portion B of the cam, as a result of which the effective cut-off is again shortened, the progressive shortening of'the cutoff being shown by the legends applied to Fig-- ure 9.

From the foregoing it will be seen that by appropriate plotting of the cam profile a number of different effective cut-offs may be obtained without requiring anyadjustment of the cam mecha--.

nism or of the valve gear. For this purpose the .cam profile may either have a gradually inclined surface in the region from the main lobe down to point 11 or may have arcuat'e "surfaces interconinected by inclines, as in'the "form herein illustrated.

,A similar action is obtainable by appropriate plotting of the exhaust cam profile. Preferably, according to the invention, the exhaust cams for forward and reverse operation (see cams H and 13 in Figure are provided with at least one portion such as indicated at E, of substantially lower height than the main lobe 126, which portion '(E) serves 'to delay the point of compression at start and at low engine speeds. At relatively high speed the effective compression'point is advanced, since the extent of exhaust valve opening provided by cam surface E is not sufficient, at the higher speed, to fully exhaust the cylinder.

The employment of cams of the type above described is of especial advantage in association with a control mechanism'of the 2-position type, since, notwithstanding the fact that the engineers control has only one forward position and one reverse position, the mechanism itself automatically effects variation of cut-01f (and also, if desired, of compression) according to the speed of operation of the engine.

The utilization of cam'profiles of the type above described is further of especial advantage in a mechanism incorporating separate rotating cams for forward and reverse operation, since the automatic variation in cut-off or compression or both does not adversely influence other valve events, such as the points of admission and release, when the engine is reversed.

From the foregoing description it will now be apparent that the present invention secures an approximation of the results of progressively adjustable valves and valve gears, without actually employing the complications of step-by-step or progressively adjustable mechanism anywhere in the system, from the control lever in the cab right down to the valves themselves. In short, the valve actuating, controlling and reversing mechanism is very greatly simplified, while preserving approximation. of the variable valve events which are desirable in locomotive engines; and the approximation is sufficient for certain types of service (such, for example, as switching engine service) merely by the use of two or three stages of Valve lift effected by the intake cam, preferably with approximately equivalent stages in compression events as effected by the exhaust cam.

The significance ofthis with relation to the cams alone (not to mention the other parts of the mechanism from the cab down to the cylinders) will be appreciated if it is first understood that a great deal of the complication and wear of the mechanism, particularly in rotating cam installations, ordinarily result from the requirement that the cam followers be progressively brought into operative engagement with different cross-sectional profiles, successively along the cams, either by shifting the cams axially, or in some other way, while the mechanism is in actual operation under load. In the first place, it has been quite difficult to secure accurate step-bystep registry of different cam profiles with the cam followers, in correspondence with the different steps of adjustment of the reverse lever in the cab. Secondly, apparatus of that nature customarily requires the use of spherically shaped rollers for the cam followers, which pro- 1 0 'vide only point-to-point contact, with resultant extreme load concentrations at the contact points, under the normal forces, accelerations, etc. of the valves and other parts. In the next place, the manufacture of elongated cams having a succession of differing profiles is itself quite a 'difiicult and expensive task.

Such problems and difficulties of the prior art are substantially obviated by the present invention, and although the specific cams herein illustrated may give only a very rough step-by-step approximation of the progressive adjustment in cut-off and other valve events obtainable by other mechanisms, the present invention can, if desired, be carried to a greater point of refinement by making the several step surfaces on the cam less marked and using more of them, or by reducing them to one continuous transition surface between the full-lift and zero-lift positions.

Numerous other advantages of the invention will be apparent without further amplification. It will also be evident that many modifications and adaptations of the invention may be made.

I claim:

1. In a steam locomotive having a cylinder and piston and a driving wheel actuated by said piston, a steam distribution system comprising valve means and associated mechanism adapted j to' cause admission and cut-off of steam wit-h reference to the cylinder effective in predetermined timed relation to piston movements at operating speeds of said driving wheel appreciably above starting conditions, and including cam means'of uniform axial contour and a profile automatically operative to cause different effective cut-offs "at different rotational speeds of said wheel without altering the admission.

2. In a steam locomotive having a cylinder and piston and a driving wheel actuated by said piston, a steam distribution system comprising valve means and associated mechanism adapted to cause release and compression of the steam with reference to the cylinder effective in predetermined timed relation to piston movements at operating speeds of said driving wheel appreciably above starting conditions, and including means automatically operative to delay the effective compression during starting operation without altering the release.

3. In a steam locomotive having a cylinder and piston and a driving wheel actuated by said piston, a steam distribution system comprising valve means and associated mechanism adapted to cause admission, cut-off, release and compression of steam with reference to the cylinder effective in predetermined timed relation to piston movements at normal operating speed of said driving wheel, and including means automatically operative to delay the effective cut-ofi and compression during starting operation without altering the admission and release.

4. In a steam locomotive having a cylinder and piston and a driving wheel actuated by said piston, a steam distribution system comprising valve means and associated mechanism adapted to cause admission, cut-off, release and compression of steam with reference to the cylinder effective in predetermined timed relation to piston movements at normal operating speed of said driving wheel, including means automatically operative to delay the effective cut-off and compression without equivalent alteration of the admission and release during starting operation, said mechanism being adjustable to cause equivalent valve events for reverse operation of said driving wheel and being adjustable through an intermediate drifting position, together with means for establishing open communication between both ends of the cylinder when said mechanism is in its intermediate or drifting position of adjustment, and means for adjusting said mechanism at will between the three major positions for forward operation, reverse operation and drifting operation.

5. In a locomotive having a cylinder and piston and a driving wheel actuated by said piston, a steam distribution system comprising valve means for admitting and cutting off the supply of steam to said cylinder, and cam means for actuating said valve means including a cam configured with a profile of varying height'in one cross section adapted to cause different effective cut-ofis at different rotational speeds and being so positioned when in operation that it entire effective profile is progressively operative upon its actuated valve means in each cycle of th driving wheel.

6, In a steam locomotive having a cylinder and piston and a driving wheel actuated by said piston, a steam distribution system comprising valve means arranged to effect release and compression of the steam in said cylinder, and cam means adapted to actuate said valve means, said cam means comprising a first cam surface characterized by uniform axial contour and a profile of varying height adapted to cause different effective valve operation at different rotational speeds of the driving wheel during forward rotation of said driving wheel, a second cam surface of uniform axial contour and a profile of varying height adapted to cause different effective valve operation at different rotational speeds of the mechanism for alternatively bringing one or the other of said surfaces into actuating relationship with said valve means.

7. A construction in accordance with claim 6 in which said piston is double acting and in which said valve means provides for establishing communication between both ends of the cylinder when said intermediate surface is in operative relationship with said valve means.

JULIUS KIRCHI-IOF.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 240,792 Wadsworth Apr. 26, 1881 1,246,954 Lentz Nov. 20, 1917 1,372,445 Milner Mar. 22, 1921 1,478,843 Turnwald Dec. 25, 1923 2,009,745 Reisner July 30, 1935 2,081,458 Lentz May 25, 1937 2,135,032 Clifford Nov. 1, 1938 2,210,328 Reidinger Aug. 6, 1940 2,235,223 Lentz Mar. 18, 1941 FOREIGN PATENTS Number Country Date 195,785 Germany Feb. 27, 1908 208,702 Germany Apr. 5, 1909 245,709 Great Britain Mar. 18, 1926 491,269 Great Britain Aug. 30, 1938

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