US2510817A

US2510817A - Self-propelled tamping roller

Info

Publication number: US2510817A
Application number: US597393A
Authority: US
Inventors: Carl F Greiner; John F Harrison
Original assignee: Buffalo Springfield Roller Co
Current assignee: Buffalo Springfield Roller Co
Priority date: 1945-06-04
Filing date: 1945-06-04
Publication date: 1950-06-06
Anticipated expiration: 1967-06-06

Description

June 6, 1950 c. F. GREINER ETAL SELF-PROPELLED TAMPING ROLLER 7 Sheets-Sheet 1 Filed June 4, 1945 Junefi, 1950 c. F; GREINER Elf-ml.

SELF-PROPELLED TAMPING ROLLER 7 Sheets-Sheet 2 Filed June 4, 1945 C. F. GREINER ETAL SELF-PROPELLED TAMPING ROLLER June 6, 1950 '7 Sheets-Sheet 3 Filed June 4, 1945 7 Sheets-Sheet 4 June 6, 1950 c. F. GREINER ETAL SELF-PROPELLED TAMPING ROLLER Filed- June 4, 1 945 I June 6, 1950 I C. F. GREINER ET'AL SELF-PROPELLED TAMPING ROLLER 'TSheets-Sheet 5 Filed June 4, 1945 June 6, 1950 C. F. GREINER 'EIAL 7 SELF-PROPELLED TAMPING ROLLER Filed June 4, 1945 7 Sheets-Sheet 6 June 6,. 1950 c. F. GREINER ETAL SELF-PROPELLED TAMPING ROLLER '7 Sheets-Sheet 7 Filed June 4, 1945 grime/mm Sew W Patented June 6, 1950 CarlF'. Gr'eifier and John F.'-Harrison-, Sp?

011w, alssignors to The Buffalo-Springfield; Roller Springfield, Ohio, a corporation of Application June 4, 1945', Serial N 0. 597,393

(Cl-.7 B ie-50 2e Claims. 1'

invention is a; novef improvement in self-'- prop'eiling tamping rollers, and the p cip'al" 01oeet tirereofi is to provide a tam-ping r'oli'er having a traction-unit and a trailing unit; each unit cat rying" paraliel tamp'in'g rolls provided with sheep'sdoot elements; each said roH being mounted for independent tilting movement on a iioz izon'iiai axis disposed parallel with them gitudinal axis of the tamping roller, the units be ing pivotaIIy connected together a manner as providea mini-mum wheelbase for the winning roller, and to provide a minim-um tut-m mg radius rendering it pos'sible to turn the temp ing roller around for the return trip instead of having to reversethe drive as in conventional tamfing rollers, the convenience aohiev'c? by turning the machinearo'u-nd after travei' the one direction being of considerable vaiue since Slilh arrangement renofers it possible to use in the tam'pi'rig roller a conventional truck or tractor type transmission with complete satisfaction; owing to" the fact that the turning aroundor the tamping' roller" Wi'lT cause the roller" to travel in the forward gear at all times; however, a reversible transmission may be used: in place of the conventional truck or tractor type transmission with complete satisfaction;

Our present invention is ani mpr'ovement' upon the tampi ng roller shown in U. S. Letters- Patent N01 212261182 issued Decemloer 24 940 to Matthew S. Rioss wh'ieh the tam-ping ro'H'er' is pro-- vi'ded with an articulated frame; and the pres ent invention is also an" improvement upon" the tampi'ng roIIe'r shown in our co-p'endii1g apnoeation, oer-arm; 555,098, filed September 2-1, 944, now Letters Patent- No. 2"-,437 ,5-2 dated March 91 1 9483 Other minor objects of the invention w-ili be hereinafter setfbrth. I

We will expia'h the" invention with reference to the accompanying drawings which show severaT ractical' embodiments thereof; to enable others familiar with the art to adopt and." use the same; anci will summarize in the claims the novel features of" construction; and n0VeI= combination of parts; for which protection is desired-i In said drawingsz Figure 1 is a side elevation of onef'orm of temp i ng roller embodying our invention.

Fig. 2 is a top piarr View, partly in section; of theftamping rol-Ier showni-nFig. V s

Fig. 3 a hori'zontalfisection on the line- 33; Fig. I, through one' ofthe drive rolls of the'trac ti'ori of thetampi'ng roiie'r shown in Fig. 1

2 showing the driving connections for the roll; and the pivots; oi the sale frame carrying: the drive roil Fig. 4; is arr entarge'di vertical section through the pivotal eonneetiorr oi the traction and traitingi unitsof tamping shown: in. Fig, 12.

Fig... 5 is a; side elevation of a modified: term: of tamping roller; embodying our invention.

Fig; 6 a; top plan view partly in section:- of the tamping: roiler'showna in 5 Fig; 7% an enlarged; vertioak section th rouglr the pivotah conneotiom between the traction! and trailing units oi: the:v tampirrg, rolier' shown" in Fi 5.

Figs 8: is: a. side elevatiorr ofi a further modified form at tamping; roile'r embodying our invention.

Figs 9 is at top plan View partly section of the tamping roller shown in- Figs, 9a is an enlarge detail" section through the pivots ofith-e center su-bir'am-eof. the traiting unite Fig. 10 is a side elevation oi the: tractionunit showni-riJE ig. 1 equipped with a gear drive instead oat a chain. drives Fig. 11: is a: horizontai section on the line Iii-4 |-,6 Figs 10. s

As shown in Figs; 1-4,; the tamping roller com,- prises a traction unit A. carrying. the drive rolls, the motor and: transmission; also the pper ators cabhousi ngthe-necessary controls andg a trailinguni-t B; carrying the trailing rolls, said units A andiB being connectedtogether b-ya pivotal connection C whereby the. units A, and B-- may be anticulated for steering purposes, the pivotal eonnection. permitting the turning, of the: trailing unit B'with-resbect to the traction unit A on th horiz'ont'al'v and vertical axes.

The traction unit A comprises a. chassis in which is mounted? a motor I, driving through speed-change gearing" contained" in; casing 2' a differential housed-I in casing, 3i,v said di'fie'rentfal beir'i'gjof' Ir-type; and units I", 2 and 3"' being? dispo'secfin' alignment; with the" difierenti'aldisposed adjacent the" rear end or the traction chassis. The motor l and parts" 2' and 3? may be covered by a Hood 4; terminating at the rear iii a. cab 5' ina mannersimilar to an ordinary truck), Said cab 5 housing the drivers' seat 6 and the necessary motor' and steering controls (not shown) Extending'from" each side of the traction. Chassis are spaced parallel" arms 1-8; the rear" arms 8' being disposed in'advance of the T-sheiift's 3a of? differential 3'. In each pair; of arms: 1-8 is journaled afreotang'ular sub fraiiie 9* pivoted as at 921' on its center Ii'ne' on a Horizontal" axis parallel with the longitudinal axis of the chassis, whereby each sub frame 9 is permitted to swing freely on its axes 9a. Mounted on an axle IE journaled in each sub frame 9 is drive r011 carrying tamping elements I2 preferably of the sheeps-foot or any other desired type, arranged in any desired manner and extending radially of the roll II.

By the above construction the rolls II, which are the drive rolls journaled in pivoted sub frames e, are thus permitted to pivot independently on horizontal axes 9a, so that in traversing the earth or ground each individual roll II may adjust itself to suit the contour of the underlying round.

The means for driving the drive rolls II from differential 3 is preferably but not necessarily substantially the same as disclosed in our co pending application Serial No. 555,093, (Patent 2,437,524) above mentioned, the drive being shown more particularly in Fig. 3. The drive rolls I I including integral hubs I Ia are freely rotatably mounted upon the axles In, the outer ends of the hubs providing suitable means to prevent axial movement of said rolls II on axles Iii. On the outer end of each drive roll II is a drive sprocket I3. On each sub frame 9 opposite the sprocket I3 is a bracket IA adapted to swing with the sub frame, said bracket being bifurcated and a shaft I5 is rotatably journaled in the bifurcations, as shown in Fig. 3, shaft I5 carrying a sprocket I6 opposite its related sprocket I3; and a chain I'I runs around each pair of sprockets I3 and I6.

The inner end of shaft I5 carries a universal joint I8; and the outer end of the adjacent differential shaft 30, carries a universal joint I9 (Fig. 3) a shaft section 25 connecting the opposed members of the universal joints I8-I9, shaft 29 being preferably splined therein as shown in Fig. 3 so as to permit elongation or contraction of the shaft assembly 3a, I9, 20, I8, l5 as the related subframe 9 pivots on its axes Set. By mounting the sprocket IE on the subframe 9 it is obvious that, as the sub-frame pivots, the relation be- P1? tween the sprockets I3 and I6 remains constant, and the sprockets remain at all times in the same plane; and hence swinging of the sub-frames 9 does not in any way affect the driving connections of the drive rolls II since the splined connections between shafts and the universal joints I8, I9 allows for lengthening and shortening of the drive for the rolls II.

The trailing unit B comprises a rectangular frame 2I with laterally projecting pairs of

arms

22, 23 at each side, in which are pivotally mounted subframes 24 of substantially similar size and shape as the sub-frames 9, said sub-frames being pivoted on horizontal pivots 240. at each end in the

arms

22, 23. In each sub-frame 24 is mounted a tamping roll 25 freely rotatably mounted upon an axle 26, each roll 25 being provided with tamping elements 21 similar to the tamping elements I2 of the drive rolls II. Preferably the rolls 25 are of the same diameter and width as the drive rolls II. Pivots 24a are preferably disposed the same distance from the longi tudinal axis of the tamping roller as the pivots 9a of the sub-frames Q of the traction unit A, so that thetamping rolls 25 carried by the subframes 2t of trailing unit B will substantially follow the drive rolls II of the traction unit A. By the above construction the tamping rolls 25 for trailing unit B are permitted to swing individual- 1y on horizontal axes in their sub-frames 24 so as to follow the contour of the underlying ground.

The pivotal connection C between the tractor unit A and trailing unit B is shown more particularly in Fig. 4, the same comprising a vertically disposed king pin 23 rigidly mounted centrally upon the rear end of the chassis of the traction unit A, as shown, preferably by means of a bracket 29, said king pin 28 having a cap plate 30 removably secured to its upper end by means of bolts 3| (Figure 4).

Pivotally mounted upon king pin 28 is the hub 32 of a horizontal drawbar 33, which hub is confined on the king pin between the bracket 29 and the cap plate 3t. Drawbar 33 carries a fixed bolt 34 (Fig. 4) disposed axially thereof extending from its rear end on which bolt 34 is pivotally mounted for rotation on a horizontal axis a drawbar terminal 35 maintained on bolt 34 by a nut 36, a bushing 3'! being preferably disposed around the bolt 3d. Thus the terminal member 35 is permitted to swivel on a horizontal axis on bolt 34. The rear end of terminal member 35 is rigidly secured in any desired manner to the center of the front end of the trailing unit B. By the above construction, the trailing unit B is permitted to swivel as a unit on both vertical and horizontal axes with respect to the traction unit A.

In order to effect steering of the tamping roller, hydraulic means are preferably provided, the same consisting of 9, depending bracket 33 on the drawbar 33 to which is pivoted, as at 39a, one end of a double-acting hydraulic cylinder 39 disposed substantially horizontally between the units A and B, said hydraulic cylinder housing a piston carrying a rod 40 the outer end of which is pivotally connected as at 4! to a bracket 42 (Fig. 2) secured to the rear end of the chassis of the traction unit A adjacent one outer side thereof. Cylinder 39 is provided with inlet and outlet pipes (not shown) connected in a pressure fluid circuit whereby fluid may be admitted into either end of cylinder 39 to shift the piston and its rod 40 to swing the units A and B on the king pin 23 thus effecting steering. The use of hydraulic steering cylinders such as 39, and their fluid circuits, is well known in the roller art; and, therefore, needs no detailed description herein The arrangement of units A and B and pivotal connections 0 provides a tamping roller having a much shorter wheel base than those heretofore constructed, with the result that the tamping roller will have a much shorter turning radius, thus making it practicable and possible to turn the tamping roller around for the return trip instead of having to reverse the drive as in the conventional tamping rollers. Tamping rollers usually travel farther in the rolling cycle than do conventional three-wheel road-rollers, and thus the general convenience achieved by our invention in turning the machine around in a short radius is of considerable value, although it may be desired to retain the conventional reversible transmission disclosed in our co-pending application Serial No. 555,098 (Patent 2,437,524) before mentioned. Our arrangement thus renders it possible to utilize the usual truck or tractor type transmission with complete satisfaction, due to better opportunity to turn the machine around and travel in a forward direction of gear at all times. Furthermore, in our novel tamping roller the driving rolls II precede and pull the trailing rolls 25, and hence the latter offer less rolling resistance than if same were pushed. Moreover,

fastener? 5. since the rolls 25 that are not driven are arranged as trailing rolls, a greater number of such; rolls 25 may be utilized. in the assembly, thus: increasing the efliciency of the; tamping roller.

By the above construction the traction unit A is articulated for steering. with respect to the trailing and supporting unit B. Thus the driving rolls II are also the steering. rolls; however, each of the rolls. H and 25 are mounted to oscillate freely in their sub-frames, 9 and. 24- at. all times to follow the ground. contour. The use: of the horizontal pivot bolt 34- on which the draw bar terminal 35 is pivoted not only allows oscillation of: the trailing unit B- with respect to the traction unit A, but also relieves frame strains as well as permits therollsto better follow the contour of the ground.

In Figs. 1-4 inclusive, the vertical king pin- 28 is disposed in rear of the axis! of axles ID of drive rolls ll of the traction unit A. But-in Figs. 5, 6, 7 a modification is shown in. which a traction unit A, trailing unit Bv and the pivotal connection C are utilized, the same being generally similar to ,7

those described in connection with the preceding Figures 1-4. However, in this modification the motor l is placed over the transmission 2 and over the differential 3, and in this arrangement the differential 3 and transmission 2 are disposed forwardly of the arrangement shown in the preceding figures to permit. the location of the vertical king pin directly over and in line with the axis of the axles IQ. of the drive rolls I I, thus providing correct steering from a geometrical standpoint. when the machine is not traveling, such arrangement being particularly desirable when loading the roller on freight cars, or turning. in. tight places while at a standstill. In this arrangement the drive shafts 3a project, from the differential housing 3' in front of the drive rolls I. 1' instead. of in rear thereof as in the preceding figures. The arrangement of shaft and sprocket drive from the difierential shaft sections 311 to drive the drive rolls I If, however; is otherwise the same as described in connection with. the preceding figures, and similar parts. are similarly lettered and hence the drive needs no detailed description herein, except to state that the brackets M for supporting. the shafts i5 of the drive sprocket It are disposed at the front outer ends rather than at the rear outer ends of the sub frames 9; as in the, preceding figures, the drive rolls liybei'rig mounted in sub frames 9 pivoted on horizontal axes as in the preceding figures.

In this modification. the trailing unit B is also. substantially identical with the trailing unit shown in the preceding figures,, and hence needs no specific description herein. In this modification the cab" 5 shown in the preceding figures is omitted; however, it is obvious that a cab may be provided above the operators seat 6, if desired.

Asabove stated, the pivotal connection C be tween the units A" and- H is disposed above and line with the axis of the axles Hlof the drive rolls- F as shown Fig. 6, the pivotal connection being shownmore particularly in Fig. 7. The king pin 28 carries a cap plate-3E5 secured by screws or bolts 3 I as in the preceding figures, the 111110 3 2 of the dlrawbar being confined between the bracket andcap plate 30: Hub 32 carries ahorizontal bolt 34 for the drawbar terminal 35 secured by a rigid frame 43 to the front end of the trailing unit B, which unit is thereby permitted to: pivot with respect to the traction unit A on the horizontal axis (bolt 34.) and vertical axis (-king pin 28) as inthe preceding figures.

' In tins modification the hub 32' of the drawba-r has rigidly secured; thereto a. bracket plate H (Figures 6, '7) normally projecting rearwardly and laterally with. respect tothe longitudinal axis: of the tam-ping roller, as shown irrFig. 6-. The outer end of the piston rod 46- ispivotally connected as at 46a to the bracket. 54, while the opposite end of the. double. acting: cylinder 39 is pivotally connected as at 3% to. a. bracket 4-5 (Fig; '2) carried by the chassis of traction unit A" at the opposite side: of the longitudinal axis or'theframe'A from the pivot Alla, as clearly shown; in Fig; 6;. Thus by admission of fluid under pressure to either end of cylinder 39 the piston; rod 4:0? will; beactuated to pivot the trailing unit B with respect to the traction unitA.

The: operation of: the tamping rollershown in Figures 5, 6., 7. is identical with that; shown in the preceding figures, but the arrangement; or the king pin 28 above the axis of the axles. l ii or the driving rolls: Il1 permits easy steering. when the machine is not traveling, which a desirable feature.

In Figures 8, 9, a further modification of the tamping roller is shown in. which the traction. unit A2 and the pivotal: connection. C2" between: the traction unit. A2. and. the: trailing unit B1 is. substantially identical withzthat shown in Figures 5, 6, '7. However, in this modification; the frame of the trailing unit B21 consists. of crossmembers 58, 5! which are: connected at their outer end'sby parallel arched frame members. 52.. Trailing unit B2 carries three individually pivoted: tamping rolls, the outer. tamping: rolls 53. being journaled in sub-frames 54 in. a manner similar to the sub-frames 24' shown in: Figure 6;. the sub-frames being pivoted on horizontal pivots. Elia; atthe outer ends of the cross members. 59, 5'! preferably under the arched frame members 52. At the forward end of the frame of trailing unit B2 is a cross member 55 (Fig. 9) provided with horizontal pivots for the sub-frame 57 of the center roll 58 As shown in Fig. the horizontal pivots for sub-frame 5? which carries center-roll sub-frame 59 for center roll 56 consists of spaced perforated lugs 56a on cross member 55 between which perforated lugs 5E on sub-frame 51' enter, pivot-pins? 56b passing through the registering perforations in the lugs 5t-5Ea. In this: manner the center roll 53 can rise or lower vertically to better followthe contour of the ground, the center roll inner sub-frame 59 being journaled for Oscillation in sub-frame 51 at pivots 60 in a manner similar to the sub-frames 5% in their pivots 54a.

The trailing unit 132 carries a rear extension B l which includes a ball socket 63, and ball head 62 connects drawbar' E4. to a trailing sub-frame 65 of the trailing roll 66; the ball and socket con-- nection permitting independent universal oscilation of the sub-frame 65' carrying roll 66- a'nd hence a pivot in the sub-frame 65' is not necessary in view of the ball and socket connection; Roll 66 is-journaled in'itssub-frame 65 in a manner similar to the other rolls.

In this modification it will be noted that the addition of center roll 58 of the trailing unit B2 and the final trailing. roll to constitute the chi-eat difference-over the arrangement shown Figures 5, 6 and '7. The machine shown in Figures 8; 9 would therefore tam'p the full width or the chine, and: two rolls would: pass over the entirearea being tamped upon each passage of the machine. In Figs. 1-7 there is considerable-space between the drive rolls: of the traction units or A and. between the rolls of thetrailingunits 1 B or B. The type shown in Figs. 8 Q better" lends itself to designs of large heavy tamping rollers.

Figs. 10 and 11 show a modification of the drive for the drive rolls H of the traction unit, gear trains being utilized instead of the chain and sprocket drives disclosed in the preceding figures. For purposes of illustration the gear train arrangement is shown in connection with the tamping roller construction shown in Figs. 1 to 3 inclusive. However, it is understood that the gear train drive may be obviously utilized in connection with any of the remaining prior modifications in lieu of the chain and sprocket drive.

In Figs. 10 and 11 the main parts are similar to corresponding parts shown in Figs. 1 and 3, and similar parts are similarly numbered. In this modification, however, the drive roll Ii carries a gear 80, in place of the chain sprocket l3 of Fig. 3, and the stub shaft l5 carries a pinion 8| disposed in alignment with gear 83. An idler gear 82 is journaled on a stub shaft 83 mounted in the adjacent side of the sub frame 9, said gear 82 meshing with both gears 89 and 8| respectively, as clearly shown in Figs. and 11. However, two or more idler gears may be utilized in place of the single gear 82, if desired.

Since the shaft I5 is journaled in bracket it carried by the sub frame 9 the same will remain at all times parallel with the axle is of the drive roll II for any tilting or swinging positions of the sub frame, and hence the gear train 86, 81 and 82 will constantly remain in proper meshing relation during swinging of the sub frame 9. Thus the gear train drive shown in Figs. 10 and 11 may obviously be applied to the modifications shown in Figs. 1 to 4 inclusive, Figs. 5 to '7 inclusive, and Figs. 8 and 9 inclusive.

The platform or frames of the trailing units B and B are well adapted to carry extra ballast, where desired. The roll diameters are unlimited by other elements of the machine such as the front roll mounting shown in our copending application Serial No. 555,098.

In each modification of machine shown by placing the driving rolls at the front end of the tamping roller, a greater number of rolls can be utilized, because the rolls which are not driven will be pulled at all times and will therefore offer less rolling resistance than if they were pushed.

We do not limit our invention to the exact forms shown in the drawings, for obviously changes may be made therein within the scope of the claims.

We claim:

1. A self-propelled roller, comprisin a, traction unit; a pair of parallel drive rolls mounted in subframes carried by said unit on horizontal pivots for oscillation on horizontal axes parallel with the longitudinal axis of the traction unit; a motor in said unit actuating a differential having laterally disposed shaft sections; devices actuated by the shaft sections for driving the said drive rolls; a combined trailing and supporting unit; a rollmonnted in a sub-frame carried bysaid trailing unit on horizontal pivots for oscillation on a horizontal axis parallel with the longitudinal axis of the trailing unit; coupling means including a vertical pivot and a horizontal pivot, said means connecting the said units together on an axis extending between said drive rolls, said connecting means permitting swinging of the units about a, vertical axis between the drive rolls and permitting relative swivelling of the units about a horizontal axis; and means for swinging 8 the units about said vertical axis to effect steering.

2. In a roller as set forth in claim 1, said devices |comprising transversely disposed stub shafts journaled in brackets carried by the subframes of the traction unit opposite the differential shaft sections; aligned sprockets carried by the drive rolls and stub shafts respectively; and chains running around the aligned sprockets for driving the respective drive rolls.

3. In a roller as set forth in claim 1, said devices comprising transversely disposed stub shafts journaled in brackets carried by the sub frames of the traction unit opposite the differential shaft sections; aligned gears carried by the drive rolls and stub shafts respectively; and idler gears journaled in the sub frames meshing with said aligned gears.

4. In a roller as set forth in claim 1, said coupling means comprising a vertical king pin carried by the traction unit in the vertical plane of the steering axles; a horizontal drawbar having a hub journaled on said king pin; and a head swiveled on said drawbar and rigidly connected with the trailing unit on the axis thereof.

5. In a roller as set forth in claim 1, said coupling means comprising a vertical king pin carried by the traction unit in the vertical plane of the steering axles; a horizontal drawbar having a hub journaled on said king pin; and a head swiveled on said drawbar and rigidly connected with the trailing unit on the axis thereof; and said swinging means comprising a doubleacting hydraulic :cylinder having a piston rod and disposed at an angle to the longitudinal axis of the roller, said piston rod and opposite end of the cylinder pivotally connecting the drawbar and traction unit.

6. A self-propelled tamping roller, comprising a traction unit; a pair of parallel drive rolls carrying tamping elements and mounted in sub frames carried by said unit on horizontal pivots for oscillation on horizontal axes parallel with the longitudinal axis of the traction unit; a motor in said unit actuating a differential having laterally disposed shaft sections to serve as a drive means; flexible and elongatable shafting extending from said differential shaft sections to serve as a drive means; driven means actuated by the shafting for driving the said drive rolls while permitting the rolls to oscillate freely; a combined trailing and supporting unit; a roll carrying tamping elements and mounted in a sub frame carried by said trailing unit on horizontal pivots for oscillation on a horizontal axis parallel with the longitudinal axis of the trailing unit; coupling means including a vertical pivot and a horizontal pivot, said means connecting said units together on an axis extending between said drive rolls, said connecting means permitting swinging of the units about a vertical axis between the drive rolls and permitting relative swiveling of the units about a horizontal axis;

and means for swinging the units about said vertical axis to effect steering.

7. In a tamping roller as set forth in claim 6, said driven means comprising transversely disposed stub shafts journaled in brackets carried by the sub frames of the traction unit opposite the differential shaft sections; aligned sprockets carried by the drive rolls and stub shafts respectively; chains running around the aligned sprockets for driving the respective drive rolls; and said flexible and elongatable shafting comprising splined sectional shafts connected at their g ends by universal joints to the stub shafts and differential shaft sections respectively.

8. In a tamping roller as set forth in claim 6, said driven means comprising transversely disposed stub shafts journaied in brackets carried by the sub frames of the traction unit opposite the differential shaft sections; aligned gears carried by the drive rolls and stub shafts respectively; idler gears journals d in the sub frames meshingwith said aligned gears; and said flexible and elongatable shafting comprising splined sectional shafts connected at their ends by universal joints to the stub shafts and differential shaft sections respectively.

'9. In a tamping roller as set forth in claim 6., said coupling means comprising a vertical king pin carried by the traction unit in the vertical plane of the steering axles; a horizontal drawbar having a hub journaled on said king pin; and a head swiveled on said drawbar and rigidly connected with the trailing unit on the axis thereof.

10. In a tamping roller as set forth in claim 6, said coupling means comprising a vertical king pin carried. .by the traction unit in the vertical plane of the steering axles; a horizontal drawbar having a hub journaled on said king pin; and a head swiveled on said drawbar and rigidly connected with the trailing unit on the axis thereof; and said swinging means comprising a double-acting hydraulic cylinder having a piston rod andd-isposed at an angle to the longitudinal axis of the roller, said piston rod and opposite end of the cylinder pivotally connecting the drawbar and traction unit.

11. A self-propelled tamping roller, comprising a traction unit; a pair of parallel drive rolls carrying tamping elements and mounted in sub frames carried by said unit on horizontal pivots for oscillation on horizontal axes parallel with the longitudinal axis of the traction unit; amotor in said unit actuating a differential having laterally disposed shaft sections; flexible and elongatable shafting extending from said differential shaft sections; driven means actuated by the shaf-tin-g for driving the said drive rolls while permitting the rolls to oscillate freely; a combined trailing and supporting unit; a second pair of parallel rolls carrying tamping elements and mounted in sub frames carried by said trailing unit on horizontal pivots for oscillation On horizontal axes parallel with the longitudinal axis of the trailing unit; coupling means including a horizontal pivot and a vertical pivot, said means connecting the traction and trailing units together on an axis extending between said drive rolls, said connecting means permitting swinging of the units about a vertical axis between the drive rolls and permitting relative swiveling of the units about a horizontal axis; and meansfor swinging the units about said vertical axis to effect steering.

12. In a tamping roller as set forth in claim 11, said driven means comprising transversely disposed stub shafts iournaled in brackets carried by the sub frames opposite the differential shaft sections; aligned sprockets carried by the drive rolls and stub shafts respectively; chains running around aligned sprockets for driving the respective drive rolls; and said flexible and elongatable shafting comprising splined sectional shafts connected at their ends by universal Joints to the stub shafts and differential shaft sections respectively.

13. In a tarnping roller as set forth in claim 11, said driven means comprising transversely disposed stub shafts journaled in brackets carried by the sub frames of the traction unit opposite the differential shaft sections; aligned gears carried by the drive rolls and stub shafts respectively; idler gears journaled in the sub frames meshing with said aligned gears; and said flexible and elongatable shafting comprising "splined sectional shafts connected at their ends by universal joints to the stub shafts and differential shaft sections respectively.

14. In a tamping roller as set forth in claim 11, said rolls of each unit being spaced apart; and the rolls of the trailing unit tracking those of the traction unit.

15. In a tamping roller as set forth in claim 11, said rolls of the traction unit being spaced apart; and the rolls of the trailing unit tracking those of the traction unit; an intermediate tamping roll journaled in an intermediate sub frame disposed between the rolls of the trailingunit; said intermediate sub frame being disposed on the longitudinal axis of the trailing unit and mounted in horizontal pivots for oscillation on a horizontal axis; one end of the intermediate sub frame being connected in the trailing unit to permit same to swing thereon on a horizontal axis transversely of the trailing unit; and a third tamping roll journaled in a third sub frame disposed in rear of the intermediate tamping roll;

said third sub frame being connected to the rear end of the trailing unit for universal swinging movement.

16. In a tamping roller as set forth in claim 11, said coupling means comprising a vertical king pin carried by the traction unit in the vertical plane of the steering axles; a horizontal drawbar having a hub journaled on said king pin; and a head swiveled on said drawbar and rigidly connected with the trailing unit on the axis thereof.

17. In a tamping roller as set forth in claim 11, said coupling means comprising a vertical king pin carried by the traction unit in the Vertical plane of the steering axles; a horizontal drawbar having a hub journaled on said king pin; and a head swiveled on said drawbar and, rigidly connected with the trailing unit on the axis thereof; and said swinging means comprising a double-acting hydraulic cylinder having a piston rod and disposed at an angle to the longitudinal axis of the roller, said piston rod and opposite end of the cylinder pivctally connecting the drawbar and traction unit.

18. A self propelled tamping roller, comprising a traction unit; a pair of parallel drive rolls carrying tamping elements and mounted in sub frames carried by said unit on horizontal pivots for oscillation on horizontal axes parallel with the longitudinal axis of the traction unit; a motor in said unit actuating a differential having laterally disposed shaft sections; said motor and differential being aligned and the shaft sections of the differential being disposed adjacent the 3 rear ends of the sub-frames; flexible and elongatable shafting extending from said differential shaft sections; devices actuated by the shafting for driving the said drive rolls while permitting the rolls to oscillate freely; a combined trailing and supporting unit; a second pair of parallel rolls carrying tamping elements and mounted in sub frames carried by said trailing unit on horizontal pivots for oscillation on horizontal axes parallel with the longitudinal axis of the trailing unit; coupling means including a vertical pivot and a horizontal pivot, said means connecting the traction and trailing units together on an axis extending between said drive rolls, said connecting means permitting swinging of the units about a vertical axis between the drive rolls and permitting relative swiveling of the units about a horizontal axis; vertical pivot of the coupling being disposed in rear of the axles of the drive rolls; and means for swinging the units about said vertical axis to effect steering.

19. In a tampering roller as set forth in claim 18, said rolls of the traction unit being spaced apart; and the rolls of the trailing unit tracking those of the traction unit; an intermediate tamping roll journaled in an intermediate sub frame disposed between the rolls of the trailing units; said intermediate sub frame being disposed on the longitudinal axis of the trailing unit for oscillation on a horizontal axis; one end of the intermediate sub frame being connected in the trailing unit to permit same to swing therein on a horizontal axis transversely of the trailing unit; and a third tamping roll journaled in athird sub-frame disposed in rear of the intermediate tamping roll; said third sub-frame being connected to the rear end of the trailing unit for universal swinging movement.

20. In a tamping roller as set forth in claim 18, said coupling means comprising a vertical king pin carried by the traction unit on the axis thereof; a horizontal drawbar having a hub journaled on said king pin; and a head swiveled on said drawbar and rigidly connected with the trailing unit on the axis thereof; and said swineing means comprising a double-acting hydraulic cylinder having a piston rod and disposed at an angle to the longitudinal axis of the roller, said piston rod and the opposite end of the cylinder pivotally connecting the drawbar and traction unit.

21. A self-propelled tamping roller, comprising a traction unit; a pair of parallel drive rolls carrying tamping elements and mounted in sub frames carried by said unit on horizontal pivots for oscillation on horizontal axes parallel with the longitudinal axis of the traction unit; a motor in said unit actuating a differential having laterally disposed shaft sections; said motor being disposed above the differential with the shaft sections of the differential disposed adjacent the front ends of the sub frames; flexible and elongatable shafting extending from said differential shaft'sections; driven means actuated by the shafting for driving the said drive rolls while permitting the rolls to oscillate freely; a combined trailing and supporting unit; asecond pair of parallel rolls carrying tamping elements and mounted in sub frames carried by said trail- 12 ing unit on-horizontal pivots for oscillation on horizontal axes parallel with the longitudinal axis of the trailing unit; coupling means including a vertical pivot and a horizontal pivot, said means connecting the traction and trailing units together on an axis extending between said drive rolls, said connecting means permitting swinging of the units about a vertical axis between the drive rolls and permitting relative swiveling of the units about a horizontal axis; said vertical pivot of the coupling unit being disposed directly above the axles of the drive rolls; and means for swinging the units about said vertical axis to effect steering.

22. In a tamping roller as set forth in claim 21, said rolls of the traction unit being spaced apart; and the rolls of the trailing unit tracking those of the traction unit; an intermediate tamping roll journaled in an intermediate sub frame disposed between the rolls of the trailing units; said intermediate sub frame being disposed on the longitudinal axis of the trailing unit for oscillation on a horizontal axis; one end of the intermediate sub frame being connected in the trailing unit to permit same to swing therein on a horizontal aXis transversely of the trailing unit; and a third tamping roll journaled in a third sub frame disposed in rear of the intermediate tamping roll; said third sub frame being connected to the rear end of the trailing unit for universal swinging movement.

23. In a tamping roller as set forth in claim 21, said coupling means comprising a vertical king pin carried by the traction unit on the axis thereof; a horizontal drawbar having a hub journaled on said king pin; and a head swiveled on said drawbar and rigidly connected with the trailing unit on the axis thereof; and said swinging means comprising a double-acting hydraulic cylinder having a piston rod and disposed at an angle t the longitudinal axis of the roller, said piston rod and the opposite end of the cylinder pivotally connecting the drawbar and traction unit.

CARL F. GREINER. J OHN F. HARRISON.

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

UNITED STATES PATENTS Number Name Date 2,226,182 Ross Dec. 24, 1940 2,230,317 Zettelmeyer Feb. 4, 1941 2,272,619 Flynn Feb. 10, 1942 2,303,336 Day Dec. 1, 1942 2,362,262 French Nov. '7, 1944