US2169917A - Road roller - Google Patents

Description

Aug. 15, 1939 R. w. KEELER ROAD ROLLER Filed Feb. 25, 1937 5 Sheets-Sheet l [/YVE/YTO RAYMOND W KEELER,

Aug. 15, 1939 R. w. KEELER ROAD ROLLER Filed Feb. 25, 1937 -5 Sheets-Sheet 2 //\/VE/\/77OF? RAYMOND W. KEELER} BY MM. 711% ATT'Y.

Aug. 15, 1939 R. w. KEYELER ROAD ROLLER Filed Feb. 25, 1937 5 Sheets-Sheet 3 /vE'/ TO R RAYMOND W. KEELE R,

BY mum 1.77

A TT'Y Aug. 15; 1939 R. w. KEELER 2,169,917

ROAD ROLLER I Filed Feb. 25, 1937, 5 Sheets-Sheet 4 f/vvE/vToR's RAYMONDW. KEELER,

ATTY

Aug. 15, 1939 R. w. KEELER I 2,169,917

ROAD ROLLER Filed Feb. 25, 1957 5 Sheets-$heet 5 Fig. 11

[N VE/YTOR RAYMOND W. KE ELE R,

Patented Aug. 15.1 939 s v I.

UNITED STATES PATENT orricn ROAD RQLIER.

Raymond W. Keeler, Gallon, Ohio, assignor to The Gallon Iron Works & Manufacturing Company, a corporation of Ohio Application February 25,1937, Serial N... 127,719

I s 5 Claims. (01. 262-8) 1 This invention relates to a road roller and parpiates' 2|, 2| which are rigidly attached to ahead ticularly to a road. roller including a scarifier or steeringpost casting 22, asby rivets. Adjacent tt t J the rear end and bottom of said-side plates 2|. An object of the invention is to provide an I provide a platform 23 which is rigidly attached 5 improved road roller construction in which the to said side plates, as by welding. 5

- scarifler will be relieved by movement of the Adjacent the front'end' of the road roller 1 roller frame in case it strikes an immovable 0b- I provide a front roller 24 which operates not onlystruction. J s to roll a surface over which the roller operates.

Another object of the invention is to provide a but also to provide for the steering of the road simple, yet eflicien-t, means to determine variably roller and the supporting of the front end thereof. '10 the depth which the scarifier teeth will pene- Said front roller 24 is rotatably mounted in a trate road surface. yoke 25 pivotallyattaehed'to an upwardly ex- I Other objects of-the invention will appear heretending post 26 'by a pin i 26 providing for tilting inafter, the novel features and combinations of said roller 24 about-a horizontal, normally lonit, being set forth in the appended claims. gitudinally extending axis as provided by said 16 In the accompanying drawings, pin I26. Said post 26 is resiliently supportedin Fig. '1 isa side elevational viewshowing a road the head casting 22 by a pluralityof coil springs roller comprising my invention; 21 which are spaced around the post 26 and are Fig. 2 is a side elevational view showing the mounted in appropriate cups carried by a plate e; rearend-of the road roller with the scarifier 11- 2B. which plate 28 rests upon a flange at thebase m lustrated in its operative position; of the post 26. It is thus seen thatthe main Fig. 3 is-a side elevational view of a portion of frame is both resiliently'and pivotally supthe road roller; taken on the opposite side from ported upon the front roller 24. v "the illustration of Fig. 2 with the proximate rear Forward and rearward scrapers 29 and 30 are g5 roller removed and with a part of the main frame pr vided t fr e th fr nt r ll r 4 o y al 35 ofthe'arrowsf 45 fied form of my invention;

' frame mounting; other parts of the roller also To provide for the steering ofth'roadrbller a being omitted in the interest of cleamess; lever, not shown, issplined to the top spline por- Figs/4 and 5 placed end to end comprise 9, tion 3| of the post 26;.which lever is operated by plan view .of the road roller comprising my ina hydraulic motor of the hydraulic system, here- 30 vention'j inafter described in. complete detail. Fig.6 is an end elevational view of said device; The driving unit for the road roller is entirely Fig. .7 is a sectional elevational view taken on flexibly mounted with respect to the. main frame the 1111-37-4 of Fig, 6 looking in the direction 20, and to provide forgthis structure I provide y Y 4 an auxiliary frame 32, best seenin Figs. 4 and 5 Fig. a is an end elevational view of the adjustof thedraw s. which auxiliary f me is fo d able shoe for the scarifier; by a pair of longitudinally extending channel Fig. 19. is a detail sectional view-showing the members 33 which are rigidly attached together mounting means for one of the arms of the paracross their fronts by an angle member 34, which allel mechanismy angle member 34 is mounted upon coil spring Fig; 10 shows a hydraulic system for controlling resilient supporting means 35 which, in turn, are. the steering and the operation of the scarlfler of mounted upon a transversely extending angle the road roller; member 36 (Fig. 1), which angle member 36 is Fig. -11 is an end elevational view of a. modirigidly attached to and extends between the side plates 2! of the main-frame 29. Fig. .12 is an end view of the scarlfier of Fig. Adjacent their rear ends the channel members 11; d 7 33-arerigidly attached toa casting 31 which forms Fig. 13 is a sectional view taken on line ls-l3 a transmission gear housing for which'housing a of Fig. 11 looking in the direction ofthe arrows. removable cover plate 88 (Fig. '5) isprovided. 50 This application is a continuation in put of The casting 31 is an elongated rearwardly ex my application fora Road building machin tending casting which forms a part of the aux- Serial No.-676,906,flled June 21,1933. 7 iliary frame 32 and also provides .a diiferential The road roller comprising my invention is' 39 to house the differential gears. and formed by a mainframe. 20 comprising a pair of the reduction gears for driving the laterally side plate cut away to illustrate more-clearly the terial which may tend to adhere thereto.

5-5 spaced parallel longitudinally extending side rear rollers 69.

' end of the main frame 20 on the auxiliary framea The rear rollers 4|] are mounted uponaxles for rotation about a fixed axis with respect to the differential housing 39 and casting 31 by virtue of laterally extending hubs 4| which are rigidly attached to said casting 31 and which have appropriate anti-friction bearings cooperating with the axles of the rollers 40, one'of which axles is seen at 4||| in Fig. 3 of the drawings. The auxiliary frame 32 with the housings 38', 39 and the hubs 4|, 4| all rigidly connected together, constitute a rigid unit in which the rear roller axles are journaled for rotation on an axis which is fixed relative to such rigid unit.

Extending laterally from the casting 31 are clutches and 43. These clutches may be separably operable and when one of them is operated, the tractor will move in a forward direction and when the other is operated it will move in a reverse direction.

Adjacent the forwardportion of the auxiliary frame 33, and rigidly mounted thereon, is an. internal combustion engine 44 for driving the road roller. Said engine 44 is rigidly attached to the casting 31, and is also rigidly attached to the auxiliary frame 32. It is thus to be seen that the engine 44 and the gear housing, formed principally by the casting 31, are supported directly from the auxiliary frame 32, the rear end of said frame being in turn supported directly from the rear rollers 40. In consequence, an appreciable portion of the weight of the auxiliary frame 32 and the elements carried thereby, will be transferred to the road surface through the rollers 40. In other words, the rear end of the power transmission unit acts non-yieldingly through the rear traction rollers 40, on material on the roadway. This is desirable as the rollers 40 preferably have a maximum crushing capacity.

While the rear end of such power transmission unit is non-yieldlngly supported, the forward end of the auxiliary frame 32 is resiliently supported on the main frame 2|].

To provide for a resilient support of the rear 22 of the power transmission unit, so that .said

.rear end of the mainframe 20 may yield upwardly with respect to the auxiliary frame 32 and the rollers 40, I provide a spring mounting between each of the hubs 4| and the side plates 2| of the main frame 20. As clearly seen in Fig. 3

of the drawings, each of the hubs 4| is providedwith a pair of upper and lower cups 45 and 46, respectively, adapted to receive coil springs 41 and 48, respectively. v

The hubs 4| are preferably square and are adapted to reciprocate vertically in the guide means provided on the side plates 2|, the structure of one of which is clearly seen in g. 3. Said guide means comprises upper and lower and side angle members 49, the upper and lower angle members being provided with bosses which extend into the coil springs 41 and 48, said coil springs 41 and 48 resting upon the inwardly extending horizontal flanges of said upper and lower angle members 45. It will thus be seen that the side-members 2| of the main frame 20 are resiliently supported upon the hubs 4 i.

Mounted upon the forward end of the main frame 25 is a radiator 50 for the engine 54. An appropriate hood 5| is also provided for the motor 44 as well as the other mechanism carried by the auxiliary frame 52, which hood 5| at its rear end is also carried by the main frame 20.

A dash board 52 is provided at the rear end of the hood 5| upon which dash boardis mounted the usual control means, such as a steering wheel 52, a brake lever 54, and the other usual control members.

An operators seat 55 is resiliently supported 5 upon the platform 23 in proper position for the operator to reach the control elements of the roadroller.

Mounted upon the rear end of the main frame 20 is a scarifier mechanism 56 comprising a transm versely extending cylindrical tube 51' of heavy material, to which is attached a pair of spaced brackets 58, 58 (see Fig. 6), said brackets being formed by a pair of similar parallel plates 55,- 55

which are rigidly attached to the tube 51, 8S 'bY welding. The brackets 58 are 50 positioned with respect to the longitudinal axis of the tube 51,

that any force transmitted to said tube 51 through a bracket 58 will be at substantially the center of the forces acting upon the tube 51 when per- 20 forming a scarifler action. This will be described more in detail hereinafter.

Cooperating with each of the brackets 58 is a pair of parallel links 60, which links are pivotally attached to the brackets 58 by appropriate pins 25 5| (see Fig. '7) provided with retaining cotter pins. Each of the links 60 is pivotally attached to a side plate 2| of the main frame adjacent the rear end portion thereof at which the platform 23 is attached thereto, to provide free swing- 30 ing movement of said links 50. The specific structure which provides for this free pivotal movement is best seen by reference to Fig. 9 of the drawings. As here disclosed, a stub shaft 52 is provided with 'a centralintegrai flange i3 and 35 witha pair of screw threaded end extensions 54 and 55. The stub shaft 62 is clamped rigidly .with the side plate 2| and a flange of the platform 23 by a nut 51 which clamps the side plate 2| and flange of the platform 22 rigidly lie-,

tween the flange B3 and the'washer 55. Thus the stub shaft 52 is rigidly attached to the main frame 20.

The link 50 is provided with a cylindrical opening which is received upon a cylindrical portion of the stub shaft 62, which portion has a width slightly greater than the thickness of the link 60, and a retaining washer 66 and nut 50 prevent the link 60 from coming of! the stub shaft 52 while providing free movement with respect thereto. It will be understood that each of. the links 60 is attached to the main frame 20 by'a stub shaft construction of the type shown in Fig. 9.

To provide for the vertical adjustment of the scarifier 55, there, is provided across-piece 15 which extends between the brackets 58 and has stub shafts 1|, 1| rigidly attached to said crosspiece 10 and pivoting in appropriate apertures in the brackets 58, whereby said cross-piece 10" may rotate with respect to the brackets 58 along its q" A piston rod 12 is pivotally longitudinal axis. attached to the center of the cross-piece 10, by a pin 13, (Fig. 6), preferably retained in place by appropriate cotter pins. It will be understood that the upper end of the piston rod 12 is provided with an appropriatepiston 8 (Fig. 10), which piston I I8 works in a hydraulic cylinder 14, which cylinder is pivotally attached to a bracket 15 by a pin 16, said bracket 15 being rigidly attached to the platform 23, as by appropriate nuts 70 and bolts. MFlgs. 1 and 2).

Adjacent each end of the tube 51 of the scarifier mechanism 56 I provide an adjustable shoe mechanism or gauge, best seen in Fig. 8 of the drawings, for adjustably determining the extent to which the scarifier teeth enter into the road surface'which is to be torn up. Each of said adjustable gauges is formed by an upstanding channel member 11 provided. with a row ofspaced apertures 18 and having a road engaging shoe 19 at the bottom thereof, the forward and rearward ends of which are up-turned to provide a skid to slide easily over the road surface.-

The tube 51 is provided with a number of 0 aligned apertures adapted to receive the reversible scarifier teeth 80 which are rigidly held in position by bolts 8| which fit into notches in the sides of said teeth 80. The teeth 80 preferably make an angle of approximately 45 degrees with the vertical and this angle will be constant i for any position of adjustment of thescarifier mechanism 58 due to the provision of the parallel link mechanism formed by the links 60. It will .be evident that the extent to which the teeth 20 80 enter the road surface operation will be determined by the adjustment of the gauge or skid comprising the channel member 11. There is, of course, such a gauge at each'end df the tube 51. Referring particularly to Fig. 6 of the drawings,

' it is to be noted that the hold-down force which will be transmitted to the scarifier mechanism 55 by the; piston rod 12 will be distributed by the cross-piece 10 to' the tube 51 through the brackets.

58. The forces on the. two sides of the tube 51, taking thepin 13 as a pivot point, will be equalized due to the fact that said tube 51 can pivot about said pin 13. Furthermore, the forces transmitted'to the tube 51 through the brackets 58 will be equalized on each side of said brackets. It is-to be noted in this connection that, by consldering either half of the tube 51, the bracket 58 is located essentially at the center of this half of said tube 51, and that there aretwo teeth 88 on each side of said bracket 58. As a conse- 40 quence, the cross-piece 1| will be effective to distribute the hold-down forces substantially equal ly to the tube 51, and thus there will be no unusual strain onany portion of said tube. It is furthermore to be particularly noted that the scarifier mechanism '56 is attached to the main frame 20, which main frame 20 does not need to partake of the movement of any of the rollers, and particularly does not need to partake of the movement of the rear rollers 40. As a consequence, when an immovable object is encountered by the scarifier in operation, the scarifier mechanism can yield either upwardly or downwardly as permitted by the springs 41, 48 'without requiring movement of any of the rollers, and particularly without requiring movement of the rear rollers 40. This provides a safety feature to protect the scarifier should an immovable object be encountered.

Furthermore, the spring mount of the rollers at 41, 48 provides for a more even operation of the main frame 20 in that should one of the rollers encounter a rough spot in the road surfaceit may roll over it without requiring a proportionate movement of the main frame. This makes 5 for more uniform operation of the scarifier in case the roller is operating on a rough road surface. In other words, the springs 41, 48, between the main frame 20 and hubs 4|, 4|, of the roller traction unit, serve to permit the scarifier to ride over obstructions in the roadway-without interfering with the operation of the rollers, and

the latter may ride over irregularities in the roadway without disturbing the operation of the scarifier. f'

In, place of the adjustable gauges above described, I may -employ anti-friction or roller type of adjustable gauges, as illustrated in Figs. 11,

12 and 13 of the drawings. In this form there are provided two of such gauges, one at each end of the tube 51, said gauges being of similar con 5 struction.

- Each of said roller gauges comprises a supporting plate I40 rigidly attached to an end of the tube 51, as by welding. Pivoted tothe plate I40 by a bolt I (see Fig. 12) is a carrier plate 142 10 provided with a stub shaft I 43 upon which is supported a road engaging wheel or roller I44. The carrier plate I42 is provided with a pliu'ality of apertures I45 (see Fig. 12) the centers of which be aligned with selected apertures I45. A pair of bolts I46 provided with appropriate nuts, extend through the said pair of. apertures and through selected apertures I45 to hold the carrier plate I42 in adjusted position.

It is manifest that by removing the bolts I46 on which the wheels I44 are journaled, the carrier plate I42 may be swung about the bolts MI, 2 thereby adjusting the elevation of the tubular carrier 51 and consequently the depth of penetration of the scarifier teeth 80. It is evident that by tightening the nuts on the bolts MI and I46, the carrier plate I42 will be clamped rigid with 3.0

, the supporting plate I40.

Referring to Fig. 10 of the drawings, there is disclosed a'hydraulic system for controlling the steering of the road roller and the-operation of r the scarifier mechanism. As disclosed in said 3 Fig 10 of the drawings, a continuously operable gear pump is provided which is continuously driven from the engine 44, The in -put to said pump is connected to an oil reservoir 9| by a pipe 92. The out-put of said pump 90 is connected to 40 a main pressure pipe 93, which pressure pipe 93 leads to a plurality of control devices, including a control valve 94 for the hydraulic piston 14 of the scarifier mechanism, a control valve 95 for the steering mechanism and a regulator 96. A re- 45 turn pipe 91 leads from each of the mechanisms 94, 95 and 96 to the oil reservoir.9|. When the control valves 94and 95 are in their non-operative position, as illustrated in Fig. 10 of the drawings, the pressure pipe 93 will be blocked at each 50 of said control valves 94 and 95. Under such conditions the regulator 96 operates to provide a substantially no-load by-pass for said pump 90.

Attention is directed to the structure of the I regulator 96 which provides this no-load by-pass. 5 Said regulator comprises a main casting 98 having an inlet port 99 connected to the pressure pipe 93 and an outlet port I00 connected to the return pipe 91. A piston IOI is mounted in a cylinder in the casting 98 and is provided with a head I02 30 adapted to close the port 99 when the piston is in its lowered position, to which it is urged solely by gravity. However, when pressure is present in the pressure pipe 93, which is transmitted to the head I02 and no counter-pressure is applied to 5 overcome this pressure, thepiston' IOI will be lifted, as illustrated in Fig. 10, providing a direct communication between the ports 99 and I 00, and

tion with a chamber I03 formed in the casting 98 7 hereinafter described, pressurein the pressure pipe 93 will be supplied tothe pipe I and will act upon the top of the piston iii. The top of the piston III has a slightly greater area than the bottom, and this, coupled with the fact that gravity tends to pull the piston Ill downwardly, will operate to close the by-pass whenever pressure is supplied to said line III, as aforesaid.

The regulator. 35 also provides a high pressure relief so that in case an excessive pressure is present in the pipe I, it will be relieved. Such pressure might be created, for example, by a, piston motor reaching the end of its stroke with the control valve,thereior in the operating position. Said high pressure relief is formed by making the piston IOI of hollow construction with a relief. port I communicating with the outlet port I00. Within the hollow piston IQI is a normally closed valve formed by a ball I and a thimble'llil providing a seat therefor. A spring I33 urges the ball I upwardly to maintain the entrance to the hollow piston I3I normally closed. However, upon the presence of an excessively high pres sure in the pipe III, the fluid therein will flow through the thimble I01 and force the ball I downwardly, escaping through the port I35 intp the outlet port Ill, thereby to relieve the excessive pressure:

Referring to the structure of the control valve 94 which controls the hydraulic piston motor for operating the scarifier and having the cylinder 14 and the piston 12, said valve comprises a casting III having a large discharge chamber III connected to the return pipe 91, and providing a central bos's Iv I2 with a pressure chamber 3 and control chambers III and II5.- The control chambers Ill and H5 are connected to control pipes H6 and H1, respectively, leading to the bottom and top, respectively; ofthe cylinder 14, thereby to control the movement of thepiston rod 12 by acting upon the piston I II associated there-. with. Said chambers III and I-ll'surround control cylinders I20 and 'I2I, respectively, which are formed integral with a control rod I22.

Reciprocal motion of the control rod I22 is controlled by a pivoted lever I23 having a handle I24. A packing gland I25 is provided to allow reciprot cation of the rod I22 without losing any oil from the discharge chamber III. with the valve 94 in the position illustrated in Fig. of the drawings, the pistons I and HI will efl'ectively seal the ends of the pipes IIS and III and thus will lock the piston II! "in its adjusted position with the cylinder 14 and the pipes Iii and H1 entirely filled with oil. That is, the cylinder 14 will be filled with oil both above and below the piston I I8 and both of the Pipes II and H1 will be filled with oil. The scarifler will thus be locked in any adjusted position against movement either upwardlyor downwardly. To move the-scariiier upwardly the lever will be operated to move the control rod I22 to the left, as viewed in Fig. 10. Un-

der such'circumstances the pressure pipe 33 will be effectively connected to the pipe I "through raised or lowered and locked in any adjusted position.

In order to close the previously mentioned bypassfor the pump 30 when the control valve 94 is operated in either direction to adJust the scari-,

fler, the pipe Ill leads to a tube I26 which extends into a bore in the rod I22. This tube I has a pair 01- ports I21 and 221 to receive fluid from the chamber H3. The rod I22 is also provided with a port I23. Whenthe rod I22 is moved to the left, as viewed in Fig. 10, ports I21 and I2.

are in communication, and thus liquid under pressure in the chamber 3 will flow into the tube I25 and to the pipe III! to close the by-pass of the regulator II, as" previously described. Whenthe rodis moved to the right, as viewed in Fig. 10, the ports I28 and 221 will provide communication between the tube m and the chamber III to produce a like result. It thus clearly appears that upon the operation of the control valve +2 94 in either direction, the regulator mechanism will immediately close the no-load by-pass for the pump ll, thus providing pressure in the pressurepipe 93 to effect the operation of the scarifier.

To providefor the steering ,ot the road whena hydraulic piston motor having a cylinder I30, a piston I3I, and -a piston rod I32 is provided, said rod I32 cooperating with a lever pivotally attached to the splined portion 3| of the post 26,

I34 are provided for the cylinder I and lead to the control valve 85. The control valve 85 has substantially the same structure as the control valve and therefore will not be described in as'previously mentioned. Control pipes I33 an'dao dctaiL- However, said control valve 85 may have' a5 an enlarged casing I35 to receive oil which may be filled at any time through the fill cap I35 to replaceany oil lost from the hydraulic system. In addition; the control rod I35, which is similar to the control rod I 22 or the vlave 94, is operated o from the steering wheel 53 by the interposition =0! a cam mechanism, not shown, which is eflec tive to translate rotary motion of the steering wheel. 53 into reciprocatory motion of the control rod I35. The steering wheel 53 is spring];

biased to a normal position which'will return the control rod I36 to the position illustrated in Fig. 10. It will be-evident therefore that the control valve 95 may be operated by the steering wheel 53 to turn the steering roller of the road roller 59, 59,- to permit limited tilting of the elongated scarifler holder '51 and the teeth carried thereby so that adjustment of the gauges at the ends of the holder can be relied on topredetermine the crowning of the roadway by the scarifying operation. That is to say, while the roller is traveling along ahardsurfaced roadway abnormally crowned, the scarifler may be held down to its work in accordance withathe adjustment of the end gauges to enable the scarifler to ,tear up-the hard surface for 're-crowning in accordance withmodern practice. The tilting adjustment is on the axis 13 shown in Figs. 6 and 11, this axis extending longitudinally of the road roller.

It should also be observed that the j pivotal connection between the lower end of the piston" the central point rod 12 and the scarifier holder is effected by ,means of an equalizer which is pivoted at II, II

for rocking movement relativelyto the carrier 51 on an axis parallel thereto and parallel tothe pivot 16 shown in Figs. 1 and 2. By referring to Figs. 1, 2, 6 and'l, it willbe seen that the 'two pairs of plates 59 are secured to the tubular vided with a plurality of spaced lateral notches 80' so that these teeth may each be held in adjusted position relative to the tubular holder 51 so as to project at various distances therefrom. During operation of the scarifier the ad- .iustment of the end shoes or end rollers relative .to the tooth holder 51, predetermines the transverse tilting of the holder on the axis 13, and when the scarifier is in operation the parallel links 50, 60 of the parallel motion mechanism act as draft devices for pulling the teeth along the roadway surface with a scarifying action. Meanwhile the hydraulic motor holds the scarifying] teeth down to their work with the end' gauge shoes or end rollers firmly pressed against the road stir-p face. Although the-hydraulic motor.|4 is-piv-- oted at 16, the scarifying teeth can not be moved upwardly relatively to the main frame because the piston 8 (Fig. 10) is locked in adjusted position by the locking of the liquid in the passageways as illustrated in Fig. 10.

Inasmuch asth'e hydraulic motor is applied at 13 through'an equalizer 10 to the road engaging shoes or rollers at the ends of the carrier 51, the hold-down force isequally distributed all along"the row of scarifying teeth. This arrangement afiords a very rugged construction whichis capable of withstanding severe forces encountered in performing scarifying oper-- tions. However, if the scarifying teeth meet with immovable obstructions which causes the main frame to be moved upwardly, such upward movement will be cushioned by the shock absorbing springs 48 of Figs. 1 and 2. Furthermore, such shocks due to the scarifying .teeth engaging immovable obstructions in the roadway. will be absorbed by the springs 35, between the forward portion of the main frame and the forward portion of the traction unit which comprises the engine, the rear traction rollers and the power transmission mechanism between the engine and these rollers.

It willalso be observed by referring to Figs. 1 and 2, that-when such immovable obstruction in the roadway has been passed over by the scarifying teeth, the sudden downward movement of the rear portion of the 'main frame will be cushioned by the upper springs 41. The lower springs 48 are relatively short but if the immovable obstruction in the roadway is relatively high, such springs 48 after being fully compressed, may act as a fulcrum for pivotal movement of the whole main frame on the axis of the rear traction rollers,

with the result that the springs 21 between the front end of the main frame and the steering roller unit will act to co-operate with the springs 48 in cushioning the shock due to the scarifler teeth rid-ing. over an unusually high immovable obstruction in the roadway. It vgll thus be seen that all of the springs 41, 48," 35 and 2'! c0- is controlled by means of the wheel ment of, my invention, Letters Patent of'the United States is:

operate to prevent shock and jar from being transmitted to the engine when. the scarifler teeth ride over an immovable obstruction in the'roadway.

It is desirable that the rear tractionrollers have a direct connection to the engine on fixed axes relative thereto, but the vibrations due to the traction unit traveling over the material to be rolled, is not transmitted directly to the operator at his station because the operator's station is on the rear end of the main frame and the latter is resiliently mounted-by means of the springs 41 on the hubs 4|, 4| of the traction unit, as illustrated in Fig. 5.

As shown in the drawings, particularly Figs. 1, 2 and 19, the hydraulic motor 14 for holding the scarifler down to its work, is controlled from the operator's station by means of the handle I24. and the leverJ23. Also from the operators station the steering of the road roller and scari-fier in Figs. 1, 2 and 10. The starting, stopping and control of speed of the engine is also effected from the operator's station, and inasmuch as thescarifier is directly under the operator's station it will be easy for him to glancedown occasionally to observe the condition of the' material being scarified andthe extent of scarifying action;

Obviously those skilled inthe art may make various changes in the details and arrangement of parts without departing from thespirit and scope of the invention as defined by the claims hereto appended, andI therefore wish not be restricted to the precise construction herein disclosed.

Having thus described and shown an embodiwhat I desire to secure by 1. In a road working machine, the combination'with a vehicle, of a scarifier, spaced apart parallel motion devices connecting said scarifier to said vehicle for adjustment in elevation relative thereto, said parallel motion devices being adapted to serve as draft connections between said holder and said vehicle, adjustable ground engaging supports connected to the ends of said .scarifier, mechanism for holding said supports predetermine the trans-' in adjusted positions to verse inclination of the scarifier in operation, a fluid pressure motor vehicle on. an axis extending transversely of the vehicle and pivotally connected to saidscarifier on an axis extending longitudinally of the vehicle, and means for controlling said motor to hold the scarifier down to its work at the aforesaid transverse' inclinationto effect scarifying operations in accordance with the desired crowning of the roadway.

2. A scarifier comprising an elongated holder,

teeth mounted thereon, spaced-apart pairs of spaced-apart plates mounted on said holder to extend radially therefrom, an equalizer pivoted at its ends to said pairs of plates, parallel motion a mechanism connected to said pairs of plates and adapted toserve as draft connections to a draft vehicle, and means pivotally connected to said equalizer intermediate the ends thereof on an 53, as shown pivotally connected to said axis extending longitudinally of the vehicle to adjust the elevation of the said holder and its teeth.

3. A scarifler for road working apparatus comprising an elongated holder, scarifying teeth ,carried by said holder, spaced-apart pairs of spaced-apart plates connected to said holder to project radially upward therefrom, an equalizer pivotally connected at its ends to said plates to rock relatively thereto on an axis spaced from but parallel to said holder, 8. fluid-pressure motor pivotally connected to said equalizer intermediate the ends of the latter, and spaced-apart parallel motion devices connected to said pairs of plates andadapted to serve as draft connections to a draft vehicle.

4. A scarifler comprising an elongated holder,

scarifying teethj carried thereby, spaced-apart depth gauge ground engaging shoes adjustably mounted on said holder, spaced-apart parallel motor comprising a depending piston rod having its lower end pivoted to said equalizing device on an axis extending longitudinally of the vehicle, said motor also comprising a cylinder pivotally connected at its lower end to said supporting bracket on an axis extending transversely-of. the rear end of the vehicle.

5. The combination with a vehicle frame, of a supporting bracket thereon, an elongatedholder, scarifying teeth carried by said holder, spaced-apart brackets on said holder, parallel motion mechanism connecting said brackets to opposite sides of said vehicle frame forwardly of the rear end thereof, an equalizing bar pivoted at its ends to said brackets in spaced relae tion to said holder to rock on an axis parallel to said holder, a reciprocating fluid pressure motor comprising a cylinder pivotally connected to said supporting bracket on an axis extending transversely of the rear end of thevehicle frame, said motor also comprising a depending piston rod pivotally connected to said equalizing bar intermediate the ends thereof on an axis extendin longitudinally of the vehicle frame, adjustable. ground engaging shoes at the ends of said holder to predetermine the transverse inclination of the holder in operation, and means for controlling, said motor to hold the scarifier teeth downto their work at the aforesaid transverse inclination to effect scarifying operations in accordance with the desired crowning of the roadway.

RAYMOND W. KEELER.

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