US2547710A - Mine locomotive - Google Patents

Description

April 3, 1951 A. LEE 2,547,710

' MINE LOCOHOTIVE Filed June 12, 1944 5 Sheets-Sheet 2 firthurlmllee A. L LEE MINE LOCOMOTIVE April 3, 1951 5 Sheets-Sheet 3 Fi led June 12, 1944 A. L. LEE

MINE LOCOMOTIVE April 3, 1951 I 5 Sheets-Shet 4 Filed June 12, 1944 ArthurlLLge aw-a2 97% If: WWW

A. L. LEE

' MINE LOCOMOTIVE April 3, 1951 5 Sheets-Sheet 5 Filed June 12, 1944 Arthurii i iee WW I; 44%

Patented Apr. 3, 1951 oumzo stares rarest orrics MINE LOCOMOTIVE Arthur L. Lee, Columbus, Ohio, assignor of one-half to Rudolf R. Schubert Application June 12, 1944, Serial No. 539,947

12 Claims. 1

This invention relates to mine locomotives and is particularly directed to a frame and running gear organization.

Two essentially inconsistent requirements must be met in such vehicles. The locomotive must, as a unit, be strong and sufficiently rigid to resist the shocks to which it is subjected and to transmit its tractive efiort from the wheels to the draw bars or couplings. On the other hand, the wheels must be mounted with sufiicient flexibility to permit them to be maintained in constant and uniform contact with the track. The problem of reconciling these two requirements is complicated by limitations of height and wheel base length that are imposed by service conditions.

These requirements are of greater urgency in locomotives of short wheel base than in locomotives of long wheel base. They are of particular urgency in locations in which the track is apt to be imperfect and impermanent-ly laid, and in stretches'in which sharp curves and variation in the tread height of the rails frequently exist. All of such cbnditions prevail in the track'used in the actual mining areas of mines, such as coal and metal mines, and the locomotives used in them are usually of short wheel base.

Prior art practice has sought to provide the necessary combination of rigid and flexible assemblies by supporting a heavy and rigid frame over axles by means of interposed springs, usually mounted directly over the journal boxes. Flexibility of the wheel mounting is accomplished by vertical motion of the axles relative to the frame. In such an organization the necessary rigidity and strength of the assembly, coupled with the strict limitation of height, has required the use of' short, relatively stiff springs, spaced longitudinally of the vehicle at a relatively small distance. The'frame of a locomotive so arranged is not stable, being subject to longitudinal rocking on the stiff and narrowly Spaced springs; such rocking being set up by starting efforts as well as by road shocks occurring during normal running. During such rocking the relative motion between the frame running gear caused by continued tractive effort of the wheels, subjects the relatively movable contacting parts of those elements to breakage and rapid wear. Rocking also imposes severe shocks and rubbing wear on the structure which connects the wheels with the frame, and impairs the useful tractive efforts of the wheels by exerting lifting influences alternately on the front and rear wheels. The tractive eifort of the locomotive is also impaired by diversion of a part of the effort to the deflection oi the frame from its horizontal position.

The vertical relative movement between frame 1 positions, momentarily to change the wheel base at one side or the other of the locomotive. .It also changes the relation between each axle and power apparatus mounted on the frame and corn nected with the axles by transmission mechanism. Changes in axle spacing involve variation in the relative angular speeds of the wheels, due to the contact of the wheels with the track and their differential movement along the track during such changes. Speed variations between the wheels mounted on the respective axles impose strains on the driving gear or driving gears, of the locomotive. Since vertical movement of the wheels is often abrupt, shocks and stresses of considerable violence are exerted on the driving gear, resulting in rapid wear, and sometimes breakage of the driving gear elements.

Changes in spacing of the wheels relatively to each other and to the driving apparatus of the locomotive also impair efficiency :of power consumption. In driving systems which are interconnected between axles, whether they be of gear or chain type, when the wheels mounted on one axle tend to slip there is a transfer of torque from that axle through the drive mechanism to the other axle. This transfer of torque, and the consequent imposition of substantially the entire driving effort on the second axle, tends to produce a continued torque transfer back and forth between the axles which perpetuates a condition in which the wheels of one axle Or the other are caused to slip. If one pair of wheels slips, torque transfer thus may cause slippage of all the locomotive wheels, with loss of traction.

An object of the invention is to provide in a mine locomotive an organization of frame and of driving and running gear; so formed and arranged as to render the frame longitudinally stable and of good riding qualities, so formed and arranged that the wheels are mounted with sufiicient flexibility to maintain them in contact with the rails without great change in weight sustention, so formed and arranged that the wheel mounting serves accurately to space the axles relatively to each other and to the driving gear; and additionally to provide an'organization which includes novel transmission and braking systems capable of highly efficient operation.

In brief, this object is accomplished by combining with a rigid frame a mounting structure serving to mount a brake system, transmission.

and wheel-mounted axles in such manner as to fix the axles against variations of spacing relatively to each other, to the brake system, and to the transmission, and which at the same time rovides the necessary flexibility of the wheels relatively to the frame to maintain the wheels in constant and uniform contact with the track. As shown the power transmission is of the sort which supplies power to both axles from a common power source.

In the accompanying drawings:

Fig. I is a side elevation of a mine locomotive constructed in accordance with my invention.

Fig. II is a top plan view of the mine locomotive.

Fig. 111 is a vertical cross-sectional view taken in the plane of line III-III of Fig. I.

Fig. IV is a vertical cross-sectional View taken in the plane of line IV-IV of Fig. I.

Fig. V is a vertical longitudinal sectional view taken in the plane of line V-V of Fig. II, shov ing the locomotive structure from a viewpoint within the width of the locomotive.

Fig. VI is a vertical cross-sectional view of the motor mounting taken in the plane of line VI-VI of Fig. II.

Fig. VII is a fragmentary horizontal view showing the locomotive transmission and its supporting arrangement.

Fig. VIIIis a plan view of the main frame of the locomotive.

Fig. IX is a side elevation of the said main frame.

Fig. X is a plan view of one of the beam members which serve to mount the transmission of the locomotive assembly and to position the locomotive axles.

Fig. XI is a side elevation of the beam members shown in Fig. X.

1 Fig. XII is a fragmentary horizontalsectional view taken in the plane of the section line XIIXII of Fig. XI, but showing additionally one of the pivot assemblies by which the beam members of the locomotive structure are pivoted on the main frame.

Describing in detail the organization shown in the drawings, the locomotive comprises a main frame having horizontal, longitudinally disposed side elements I and 2, cross elements 3 and end structures 4 that include draw bar couplings 5.

The frame is a massive and rigid structure adequately strong to resist shocks and strains of mine hauling, and to transmit hauling strains to and from the couplings 5.

The side elements l and 2 have relatively wide vertical inner surfaces 6 that form bearing surfaces for beam members I and 8, which lie alongside the surfaces 6 and are centrally and individually pivoted to the respective side elements I and 2 of the frame for independent vertical swinging. The beam members I and 8 cooperate to provide mounting structure connecting the frame with and supporting it on axles 9 and IE. Mounting structure also is provided for a power drive transmission H, the driving motor and a brake system.

Each of the pivot assemblies (see Fig. IV) comprises a horizontal, transversely disposed pivot pin [2 mounted in a boss I3, which projects inwardly from the inner surface of each of the beam members and to which boss the pin [2 is keyed by a transverse through bolt 14. The pivot pins i2 are extended outwardly beyond the outer surfaces of the beam members I and 8 in which hey are respectively secured and their outer ortions are rotatively engaged in bores of pivot blocks l6 wherein they are secured by enlarged heads I! received in recesses IS in the outer surfaces of the pivot blocks. lhe pivot blocks 16 are vertically slidable in windows 28 in the side members i and 2, and are engaged for sliding movement between the vertical edges 2i thereof. The height of the windows 20 is such as to permit limited relative vertical motion between the frame and the organization comprising the pivot assemblies and beam members I and 8.

The beam members 1 and 8 each are provided with longitudinally spaced cut-outs 22 that are arranged in transverse opposition. The edges 2-; of the beam members at the sides of these cutouts are vertical and engage between them journal boxes 25 that are mounted on the axles, so that the axles are fixed against movement longitudinally of the beam members. The journal boxes have vertical front and rear surfaces 26 that contact the edges 24 and these surfaces carry projecting ribs 2?, (see Fig. III) spaced apart a distance greater than the thickness of the beam members to maintain the axles against displacement laterally of the vehicle.

" Cut-outs 22 of the beam members each align with cut-outs 28 of the main frame, in which also the journal boxes lie. The edges of the beam members that form the tops of the cut-outs are formed as horizontal bearing flanges 29 which rest on top surfaces 30 of the journal boxes. To provide tilting of the axle and journal box assemblies relatively to the beam members, the top surfaces 30 of the journal boxes are crowned transversely of the vehicle.

The frame of the locomotive is longitudinally stabilized on its central pivot mounting by springs spaced equally fore and aft of the pivot point (see Figs. V and VI) and interposed vertically between the frame and the beam members at points longitudinally outside the respective axles 9 and I0. Spring-supporting platforms 3| are extended inwardly from the lower edges of the beam members i and 8, and carry coil springs 33. Coil springs 33 seated on the platforms 3| bear upwardly against the under side of brackets 34, which extend inwardly from the upper regions of the side elements l and 2 in overlying relation to the platforms. The long spring base thus provided gives longitudinal stability which is independent of the wheels in-so-far as longitudinal rocking of the frame is concerned. For a given wheel base the locomotive frame thus has unusually good stability on the wheels. Because the springs are in each instance spaced away from the journal construction, it is possible to make the springs 33 long, as shown, the full height of the locomotive being available to mount the springs. Commonly, the springs are mounted over the journals and their height is definitely limited by that mounting. Because the transverse pivot of the frame is central and the springs are spaced widely from it, little or no journal movement is caused by any anticipated inequality in the vertical positions of the wheels on the rails. The clearance for vertical movement provided in cut-outs 28 of the main frame accommodates to transverse rocking of the axles, and with the clearance in window 20 accommodates to spring deflection in cushioning vertical inertia of the main frame.

As shown in Figs. II and IV the axles 9 and I0 are driven by the transmission II, the gearing of which is enclosed in a casing 35 (see also Fig. VII) and supported by the beam members 1 and 8. This support is accomplished by a cross aaivyi-o bar 36 that is mounted at its ends 31 arises for horizontal swinging movement inhangers 39 and 40, respectively mounted to the beam members land '8 by vertical bolts 4!. The end '38 of the bar 35 which serves as the pivot end (shown to the right in Fig. VII), is provided with laterally rounded cheek pieces 42 that lie between vertical surfaces d3 of the hanger 40 and is therebyheld with its pivotal axis along a vertical plane extended between the axesof the pivot pins -2. The other end 3? of bar 36 is s'lidable along a horizontal surface 33 of the hanger .39. The transmission assembly H as shown in Fig. IV, which is secured rigidly to bar 36,-comprises a final drive shaft 4 1. This iinal drive shaft thus is mounted on the crossbar $28 in such way as to be movable with it, and is so arranged as to overlie the cross bar. The axis of shaft M closely approaches the axis of pivotal motion of the beam members I and 8 relatively to the main frame. Support of the transmission assembly upon the pivota'lly movable bar 36 permits the assembly to swing horizontally. Vertical adjustment of hangers 39 and it] may be effected by increasing or decreasing the length of their suspending bolts 4|, as by their threaded connection with the hangers, to adjust the hangers and the drive shaft to a determined vertical position with respect to the wheel-carrying axles.

The transmission casing 35 carries a frame .5,

which is extended longitudinally of the vehicle and terminates in supporting structure for mounting a motor 26. Support for the motor is provided by nut-carrying bolts 41' that vertically suspend the frame 45 from a cross member 48 of the frame. Both the heads of bolts 4'! and the nuts 41a associated with the bolts have semispherical bearing surfaces 49 that permit the bolts to swing in accommodation to the horizontal swinging of the frame. of the bolts thus accommodates the motor to swinginguncler gravity and tends to recenter the support when deflected. The motor support thus exerts a vertically directed force which tends (in the manner-of a pendulum) to recenter the drive when deflected.

The transverse final drive shaft M as shown in Figs. II and VII is extended from the casing 35' of the transmission in the direction of the slidablo end 3? of the supporting bar 36 to a point near the beam member I upon that side, and adjacent its end carries sprocket wheels 50 and 5'! that are coupled respectively by sprocket chains e i and 55 with sprocket wheels 52 and 53 mounted on the axles 9 and it. It is to be noted that the sprocket chains are located to one side of thelong-itudinal center line of the vehicle and adjacent the journal boxes on that side. The Organization of the transmission assembly func- "tions to lessen inequality in tractive effort between the wheels of the two axles, and to counteract tendency of either transverse pair of wheels to slip under power application to the wheels exceedingtheir adhesionof the rail Assuming a given total load for both'pairs of wheels, it frequently happens that because of conditions existing throughout the hau'l such as unequal weight'distribution, or conditions existing temporarily under one pair of wheels such as wet track, one pair of wheels has less rail adhesion than the other. In building up to the maximum tractive e'fiort of both pairs, it is desirable to assume the load without marked slippage of the wheels and without a surging effect in which slippage passes back and forth between Tilting movement 1 the :wheels of the two axles by alternate over loading of the pairs of wheels beyond their .adhesion to the rails. Thus as the pair of wheels having lesser rail adhesion tends to slip and to present less reaction to the driving force of the sprocket, the driving shaft and sprocket crawl slightly toward the other pair of wheels, because of the physical requirement for equality in the reactions to the driving force. This action continues progressivelyin small increments of movement. until the slack of the chain having the lesser adhesion to the rails is exhausted by increase in center distance, and maximum tractive effort at each axle is produced. At this time the unbalance in the driving forces has been absorbed as a reaction in what is normally the slack reach of the chain driving the wheels capable of the lesser tractive efiort, and during the adjustment there has been no wheel slippage within the limits of the tractive effort the locomotive can produce under the existing conditions. The pendulum effect of the motor and transmission moun ing tends to restore the sliding end of the transmission-supporting bar and the transmission shaft to central position, equally spaced from the axes of the two axles.

To explain the action in somewhat different terms, movement of the driving sprocket away from the axle the wheels of which have the lesser adhesion to the rails supplies in the assembly the reaction to the driving force which is lacking .because of such low rail adhesion. This prevents a demand for excessive reaction from being imposed on the wheels carried .by the other axle, and permits both pairs of wheels vto respond to power application apportioned to their grip on the rails.

The drive thus can build up to maximum tractive eiTort without any wide adjusting movement of the driving sprockets, and withoutsurgingin the transmission of power to the axles. This corrective action takes place when slippage tends to co ur at either pair of wheels, by measured adjustment to variation in the tractive effort, the motor and transmission support acting :in yielding opposition to the crawling movement at the sprocket end of the drive shaft by which tractive effort is apportioned. There is no oppcrtunity for a slipping tendency when once created progressively to increase 'by progressive decrease in adhesion to the rails, as with sprocket drives previously in use, or for the tractive effort to be thrown wholly to one pair of Wheels by definite slippage of the other pair. The driving organization thus preserves to a maximum extent the total existing adhesion of the wheels to the rails, by allowing the driving sprocket and chains to assume their best position for maximum total tractive effort by smooth automatic adjustment.

The beam members 7 and 8, in addition to their previously indicated functions, serve to mount a brake system as shown in Fig. IV. Adjacent each wheel a brake supporting pin 56 is mounted, on the appropriate one of the beam members I "and 8, and projects outwardly through the side elements I and 2 of the frame by way of windows bl, which are of suflicient size to provide clearance for the pins during relative movement of the beam members and the frame. On these pins 5c are brake arms 58 to which brake shoe assemblies 59 are pivoted by pins 60. On each side of the locomotive is an operating lever 65 pivotally connected with one of the brake arms '58 and coupled with the other brake arm 58by means of a link 62. The levers 6| on the opposite sides of the frame are connected by drag links 64 with a transverse bar 65 slidably supported by the beam members i and 3 and having ends that laterally project through slots 66 in the frame side elements i and 2. The bar 65 is moved longitudinally of the vehicle by a screw and nut operating organization 81 having a hand wheel 68.

At the end of the locomotive opposite the motor mounting, and at which the hand wheel 58 is located, anoperators platform 69 is mounted on the frame. On this platform are mounted an operators seat 70 located to give access to control devices such as the hand wheel 68, a motor controller l I, and a service brake control 12 that operates a brake mechanism 13 operatively associated with the transmission II.

From the above it will be seen that the beam members I and 8 serve to fix the spacing of the axles 9 and i0, flexibly to connect the axles with the rigid frame in a way precluding their movement longitudinally of the frame, and to provide mountings for the transmission and the brake system so that their spacing is substantially fixed relatively to the axles and to the wheels. In operation of the locomotive the following effects are achieved.

In starting, stopping and running, the efforts of the wheels are transmitted to the frame through a system of rigid parts unyieldingly related in the direction of the tractive effort, such parts comprising the axles, journal boxes, beam members and pivot assemblies. There is therefore no wearing and damage due to abrupt contact between relatively movable parts interposed in the line of tractive effortdelivery between the axles and the couplings. The widely spaced springs, which by reason of their mounting beyond the axles and within the vertical limits of the frame elements I and 2 may be of substantial length, and therefore have a low rate of increase or decrease of weight sustention when deflected without exceeding the height limitations of the locomotive, serve adequately to stabilize the frame against longitudinal rocking. Stability of the frame is improved in that the vertical motion of the wheels in passing over track irregularities, instead of being transmitted directly to an overlying frame through short stiff springs, is compensated by the swinging action of the beam members, acting to transfer a portion of the load of one spring to the other spring upon the same side. The wire spacing and low weight sustension rate of the springs, coupled with the central support of the frame by the pivot assemblies, causes the transfer of spring load to take place without transmission of substantial vertical impulses to the frame through the springs. Since the action of the beams is pivotal, and the distance between the pivot axis and the axles is substantial, there is very little vertical motion imparted to the frame through the pivot assemblies. When the wheels are subjected to a violent vertical shock sufficient to cause the frame to jounce, the frame is permitted to move vertically relative to the beam members by the sliding motion of the pivot blocks iii in the side elements i and 2, and such motion is cushioned by all of the springs.

As above indicated, important advantages resuit from the combination of the rigidly spaced axles, the mounting of the transmission on the beam members, which provide rigid axle spacing and flexibility of wheel mounting relatively to the frame, and the arrangement of the transmission for horizontal swinging along a plane extended longitudinally of the vehicle. This result is that the assembly lessens transfer of torque from wheels resting upon slippery track surfaces and tending to spin to the other wheels not having such tendency, thereby ensuring a more equal delivery of power to both axles. It will be seen that rigid spacing of the axles relatively to each other and to the transmission is a factor in effecting the automatically equalized power delivery above described. Arrangement of the swinging transmission upon the frame of a prior art locomotive having vertically movable spring-mounted wheels would fail fully to provide the intended effect, because the constant change in centers would interfere with the smooth adjustment to inequality in rail adhesion provided by the transmission mounting.

Mounting of the braking system on the beam members also produces advantageous results. Arrangement of the brake shoe assemblies on supports that move with the beam members, and therefore with the wheels with which they are cooperatively organized, avoids the necessity of providing lost motion connections in the brakeoperating mechanism to compensate for relative motion between the wheels and a brake system mounted on a relatively movable structure. Consequently, the entire motion of the brake operating connections is used to give mechanical advantage, producing great power in the movement of brake shoes through a correspondingly shortened distance. In my braking organization mechanical advantage is achieved by long operating arms and short power-delivery arms of the brake levers.

Having specifically described one physical embodiment of my invention, it is to be understood that my invention is not restricted thereto, but that such changes in form and arrangement as may be made within the terms and sense of the claims appended hereto come also within the bounds of my invention.

I claim as my invention:

1. In a railway locomotive comprising a frame and transverse axles; beam members spaced transversely and disposed longitudinally of the frame and each connected with both axles rigidly to fix their spacing, pivot structure centrally intermediate the axles connecting the respective beam members to the frame for vertical swinging movement relatively to each other and to the frame, a power transmission including a transverse drive shaft supported between the beam elements for horizontal swinging movement of one of its ends, and individual endless powerdelivery means connecting the said movable end of the transverse drive shaft with the respective axles.

2. In a railway locomotive comprising a frame and transverse axles; beam members spaced transversely and disposed longitudinally of the frame and each connected with both axles rigidly to fix their spacing, pivot structure intermediate the axles connecting the respective beam elements to the frame for vertical swinging movement 1ongitudinally of the vehicle and relatively to each other and to the frame, a transmission-supporting member pivotally supported by one beam member and slidably supported by the other beam member for horizontal swinging, a transmission assembly mounted on the said supporting memher and including a final drive shaft disposed transversely of the vehicle for swinging with the supporting member, and individual endless '9 power-delivery means connecting the said drive shaft to the respective axles.

3. In a railway locomotive comprising a frame and transverse axles carrying rail-engaging wheels; a drive comprising a cross-member mounted to swing from one end thereof, a drive shaft arranged to swing with said cross-mem her and having driving members thereon adjacent the swinging end thereof, and driven members on the. said axles each having flexible endless driving connection with said drive shaft oppo sitely to present reaction to the driving force of said shaft and the driving end of the shaft by its swinging motion bein movable toward that axle presenting the greater reaction.

4. In a railway locomotive comprising a frame and transverse axles carrying rail-engaging wheels; a transmission comprisin a drive shaft arranged to swing along one side of the locomotive, and individual flexible endless driving connections between the said drive shaft adjacent its swinging end and each of the said axles oppositely to present reaction to the driving force of said shaft and the driving end of the shaft by its swinging motion being movable toward that axle presenting the greater reaction.

5. In a railway locomotive comprisin a frame and transverse axles carrying rail-engaging wheels, a transmission supporting structure comprising members pivoted to the frame between said axles, springs vertically interposed between said pivoted members and the said frame at points longitudinally beyond the said axles, a transmission including a drive shaft carried on said supporting structure by a cross-member mounted to swing from one end thereof, driving members on said drive shaft adjacent the swinging end thereof, and driven members on said axles each having flexible endless connection with one of the driving members on said drive shaft oppositely to present reaction to the driving force of the shaft and the driving end of the shaft by its swinging motion being movable toward that axle presenting the greater reaction.

6. In a railway locomotive comprising a frame and transverse axles carrying rail-engaging wheels; a transmission supporting structure comprising beam members pivoted to the frame between said axles, springs vertically interposed between the said beam members and the frame at points longitudinally beyond the said axles, a transmission comprising a drive shaft mounted to swing along one side of the locomotive carried by the said supporting structure, and individual flexible endless driving connection between the said drive shaft adjacent its swinging end and each of the said axles oppositely to present reaction to the driving force of said shaft and the driving end of the shaft by its swinging motion being movable toward that axle which presents the greater reaction.

7. In a four-wheel railway truck assembly in cluding a side frame and spaced wheel-carrying axles; the combination of a beam extended longitudinally of the said frame in juxtaposition and lateral parallelism therewith and confined against relative fore and aft and bodily vertical movement with respect to the axles, a pivot assembly for the said beam comprising a bearing-block longitudinally spaced between the axles and vertically movable in the said frame and a horizontal pivot member therein engaged with the beam for rotational movement of the beam with respect to the bearing-block and the frame, and

" in the organization the said independent yielding elements longitudinally spacedon both sides of the said pivot assembly connecting the said beam in stabilizing relation with the same frame vertically to transmit load to the said frame at points longitudinally removed from the said pivot to relieve the'pivot of the load weight of the frame, saidiongitudinally spaced yielding elements' sustaining the total load transmitted between thesaid frame and the said beam, in the organization the said beam transmitting tractive effort longitudinally to the said pivot assembly on which it swings independently of deflection of the said yielding load transmitting elements. I

8. In a ioiir whcel railwaiy truck assembly including a frame and wheel-arrl ing axles; the combination of two transversely spaced beams extended longitudinally of said frame in juxtaposition and lateral parall'elism therewith and confined against relative fore and aft and bodily vertical movement with respect to the axles, a

pivot assembly for each of the said beams comprisinga bearing-block longitudinally spaced be tween the axles and vertically movable in the said frame and a horizontal pivot member there in engaged with the beam forrotaticn l meve= ment of the beam with respect to the bearing= block and the frame, independent yielding ele= ments longitudinally spaced on both sides of the said pivot assemblies connecting the said beams in stabilizing relation with the said frame ver= tically' to transmit load to the said frame at points longitudinally removed from the said piv= ots to relieve the pivots of the load weight of the frame, saidlongitudinally spaced yielding elements sustaining the total load transmitted between the said frame and the same beam, in the organization the said beam transmitting tractive effort longitudinally to the said pivot assemblies on which they swing independently of deflection of the said yielding load transmitting elements, and a transmission system effective on the said axles' mountedon the said beams.

9. In a four-wheel railway truck assembly including a sid frame and spaced wheel-carrying axles; the combination of a beam extended longitudinally of the said frame in juxtaposition and lateral parallelism therewith in supported relation with the said axles and confined against relative fore and aft movement with respect thereto, independent and longitudinally spaced yielding elements interposed between the said beam and the said side frame in stabilizing relation with the said frame vertically to transmit load to the said frame at longitudinally spaced points, and a vertically floating and longitudinally confined horizontal pivot mounting for the said beam positioned in the frame between the said yielding elements and between the said axles for rotational movement of the said beam with variations in relative load transmission by said yielding elements, said longitudinally spaced yielding elements sustaining the total load transmitted between the said frame and the said beam, beam transmitting tractive effort longitudinally to the pivotal mounting on which it swings without vertical loading of the said pivotal moun-iing.

10. In a fourwheel railwa truck assembly including a side frame and spaced wheel-carrying axles; the combination of two transversely spaced beams extended longitudinall of the said frame in juxtaposition and lateral parallelism therewith in supported relation with the said axles and confined against relative force and aft movement with respectthereto, independent and longitudinally spaced yielding elements interposed between each of the said beams and the said side frame in stabilizing relation with the said frame vertically to transmit load to the said frame at longitudinally spaced points, vertically floating and longitudinally confined horizontal pivot mountings for the said beams positioned in the frame between the said yielding elements and between the said axles associated with each said beam for rotational movement of the beam with variations in relative load transmission by said yielding elements, said longihdinally spaced yielding elements sustaining the total load transmitted between the said frame and the said beam, in the organization the said beams transmitting tractive efiort longitudinally to the pivotal mountings on which they swing without vertical loading of their'said pivotal mountings, and a transmission system effective on the said axles mounted on the said beams.

11. In a self-propelled railway vehicle the combination of a frame comprising side beam members and two longitudinally spaced axles with a power transmission adapted to prevent wheel slippage and produce the maximum tractive effort afforded by the weight of the vehicle in starting the vehicle regardless of the diversity of adhesion of the individual wheels, said power transmission comprising a driving shaft, two individual flexible endless driving connections between the said driving shaft and the said axle-s, and supporting means for the said driving shaft mounted on said beam members for movement longitudinally of the said beam members, said axles exerting through the endless driving connection of each, forces oppositely reactive to the driving force of said horizontally movable driving shaft to-move the driving shaft toward that axle presentingthe greater reactive force un.il equalization of such forces is attained between one or both reaches of one flexible endless connection and one or both reaches of the other said connection. 12; In a self-propelled railway vehicle the combination of a side frame and two longitudinally spaced axles with a power transmission adapted to prevent wheel slippage and produce the maximum tractive effort afforded by the weight of the vehicle in starting the vehicle regardless of the diversity of adhesion of the individual wheels, said power transmission comprising a beam having swinging connection with the said frame intermediate the axles and having longitudinally fixed relation to the axles, a driving shaft, supporting means for said shaft mounted on said beam for movement 1ongi.udinally of said beam, two individual flexible endless driving connections between the said driving shaft and the said axles, said axles exerting through the endless driving connection of each forces oppositely reactive to the driving force of said horizontally movable driving shaft to move the said driving shaft toward that axle presenting the reatcr reactive force until equalization of such forces is attained between one or both reaches of one flexible endless connection and one or bo.h

reaches of the other said connection.

ARTHUR L. LEE.

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

UNITED STATES PATENTS Number Name Date 3,962 Ray Mar. 21, 1845 831,948 Gundersen Sept. 25, 1906 1,062,172 Levin May 20, 1913 1,073,812 Muhlfeld Sept, 23, 1913 1,947,683 Townsend Feb. 20, 1934 2,174,675 Woodard Oct. 3, 1939 2,412,657 Stoltz Dec. 17, 1946

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