US2127485A

US2127485A - Road roller

Info

Publication number: US2127485A
Application number: US106002A
Authority: US
Inventors: Clifford A Owens; Fred L White; Earl I Beicher
Original assignee: OSGOOD Co
Current assignee: OSGOOD Co
Priority date: 1936-10-16
Filing date: 1936-10-16
Publication date: 1938-08-16
Anticipated expiration: 1955-08-16

Description

Aug. 16, 1938. c. A. OWENS ET AL ROAD ROLLER Filed Oct. 16, 1956 3 Sheets-Sheet l TORS Owens. Fred L. wh/fz- B Earl Beicher: W

ATTORNEYS.

MA. W

' 1938- c. A. OWENS ET AL 2,127,485

ROAD ROLLER Filed Oct. 16, 1936 3 Sheets-Sheet 2 N TORS A. Owens.

ATTORNEYS. 2

Patented Aug. 16, 1938 ROAD ROLLER Clifford A. Owens, Fred L.

White, and Earl I.

Beicher, Marion, Ohio, assignors to The Osgood Company, Marion, Ohio Ohio, a corporation oi.

Application'october 16, 1936, Serial No. 106,002

14 Claims.

Our invention relates to a road roller. It has .to do, more particularly, with a road roller of the ordinary type which is provided with an attachment for effectively ironing out high spots and irregularities in the road surface being rolled. A road roller has been provided in the past with an auxiliary roller adapted to iron out the irregularities in the road surface. However, this prior art road roller has been possessed of certain disadvantages. This prior art road roller comprises two rear rolling wheels, a forward rolling wheel or roller of a width greater than the distance between the inner edges of the rear rollers, and a small ironing roller which is located intermediate the front and rear rollers. Hydraulic pressure means is provided for forcing the ironer roller in contact with the road surface. The location of the intermediate ironer roller and the nature thereof results in certain drawbacks. This roller is adjustable into several positions and several passes over the road surface, with the ironer roller set at a different position during each pass, are necessary toieffectively iron out the irregularities in the road surface. The pressure exerted by the ironer roller is dependent upon the weight of the entire roller. There is a tendency when the ironer roller strikes an incompressible object or high spot, for either the steering-front roller or the traction rear rollers to be lifted off the surface. Thus, it is apparent that the entire weight of the machine may be exerted on the ironer roller which may result in too much pressure being applied to the road surface with the result that the road structure may be broken down due to the excessive pressure.

One of the objects of our invention is to provide a road roller of the ordinary type with an ironer roller which is of such a type that the irregularities in the road surface will be effectively ironed out with the result that a very smooth road surface will be obtained.

Another object of our invention is to provide a road roller of the type indicated which is provided with an ironer roller, the ironer roller being provided with fluid actuated means for forcing it in contact with the road surface which is of such a nature that the pressure applied to the road surface by the ironing roller may be varied.

' Another object of our invention is to provide a road roller of the type indicated which is provided with an auxiliary ironing roller and which is provided with means for preventing excessive amounts of pressure being exerted on the road structure when the ironing roller passes over an incompressible object or high spot.

Another object of our invention is to provide a roller of the'type indicated in the preceding paragraph wherein means is provided for pre- 5 venting the steering roller or the tractions rollers from being moved out of contact with the road surface when the ironing roller passes over an incompressible object or high spot.

In its preferred form our invention contem- 10 plates the provision of a road roller of the ordinary type embodying a main frame, a steering roller mounted on the forward end thereof and two larger traction rollers mounted at the rear end thereof, the steering roller being of greater 15 width than the space between the two rear traction rollers. On the rear end of the frame behind the traction rollers we mount an auxiliary roller which may be termed an ironing roller. This roller preferaby is of such a width that it 20 operates over the entire surface previously rolled by the main rollers provided on the machine. We preferably provide cylinder and piston mechanism for causing the ironer roller to exert a predetermined pressure on the road surface so 25 as to iron out any irregularities thereof. However, in order to eliminate any danger of too much pressure being exerted on the road surface by the ironer roller, which might cause breaking down of the road surface, we provide a 3 compensating cylinder which may be set to limit the pressure exerted by the ironing roller to a predetermined maximum. If the ironing roller passes over an incompressible object or high spot tending to lift the rear traction rollers from the 35 surface, this compensating cylinder will automatically'operate to prevent lifting of the traction rollers from the road surface.

The preferred embodiment of our invention is illustrated in the accompanying drawings where- 40 in similar characters of reference designate corresponding parts and wherein:

Figure 1 is a side elevation of a road roller provided withour ironing roller attachment.

Figure 2 is a perspective view showing the ironing roller attachment which is mounted on the rear end of the road roller.

Figure 3 is a rear elevation, but partly in section, of the road roller showing the ironing roller 50 attachment and the operating mechanism therefor.

Figure 4 is a longitudinal section showing the ironing roller attachment and the manner in which it operates. 5

Figure 5 is a plan view of the entire road roller.

With reference to the drawings, and particularly to Figure 1, we have shown an ordinary road roller comprising a main frame I having a steering roller 2 Suitably mounted on thefront end thereof and a pair of traction rollers 3 mounted at the rear end thereof. It will be apparent from Figure 5 that the roller I is wider than the space between the inner edges of the traction rollers 31 At the/rear end of this road roller we provide an ironing roller attachment which serves to effectively iron out the high spots in the road surface. This attachment comprises an ironing roller 4 which is of comparatively small diameter so that it will more effectively iron out the high spots and produce a smooth surface. This roller 4 is preferably of such a width that it-operates upon the entire surface previously rolled by the

rollers

2 and 3. However, the roller 4 may be of any desired width.

The roller 4 is carried by an axle which is carried in hubs 6 at each end thereof. Each hub 6 is provided with a pair of integral upstanding lugs 1 between which the lower end of a link 8 isdisposed. The end of the link is pivoted to the lugs by means of a pin 3. The upper end of the links 3 are pivoted to a transversely extending supporting member l as at H. Intermediate its ends this supporting member l0 has a pair of forwardly extending li nks'l2 which are integraliy secured to the .member ID at their rear ends but which have their forward ends pivotally connected as at l3 to the rear end of the frame i. A yoke member l4 extends forwardly from the hubs 6 and transversely in front of the roller 4. This yoke structure is of channel cross section as illustrated best in Figure 4 and is provided with a rearwardly extending blade I secured to its upper edge and a rearwardly extending blade l6 secured to its lower edge by means of bolts l1. These blades are so disposed that their edges are substantially in contact with the roller 4. They serve to scrape the surface of the roller and to keep it clean. A space is formed between the blades i5 and it which is preferably filled with some absorbent material as indicated at II. A sprinkling device l9 supplies oil or water to the surface of the roller, part of which will be absorbed by the material l8, and thus the roller will be kept clean. The oil or water will prevent sticking of the road material to the roller. Furthermore, the blades l5 and It will scrape the roller to keep it clean. The sprinkling device I9 is preferably carried by the member iii. A second pair of links are provided for connecting the ironer roller to the frame I. These links 20 have their forward ends pivotally connected to the frame as at 2| a substantial distance forward of the pivot points I3. The rear ends of these links 20 are bolted to forwardly extending members 22 which are integrally secured to the yoke I4.

Thus, it will be apparent that the roller 4 is rotatably carried by a structure which is pivotally connected for vertical movement to the rear end of the frame i by means of the links l2 and 20. We provide means for movement of the roller 4 so that this roller will apply a predetermined pressure to the road surface. This means is hydraulically operated and will now be described in detail. 1

We provide a cylinder 23 which is mounted at its lower end on trunnions 24 rotatably mounted in upstanding lugs 25 secured to the frame I.

' end of the cylinder producing downward,

This cylinder 23 has a piston 26 operating therein (Figure 3) which has a depending piston rod 21 connected thereto. This piston rod 21 passes through a packing 'gland 21a at the lower end of the cylinder and extends downwardly from the lower end of the cylinder. The lower end of this piston rod 21 is pivoted as at 28 to a pair of upstanding lugs 29 integrally ber l0. Thus, it will be apparent that the cylinder 23 is pivotally secured to the rear 'end of the frame I while the piston rod 21 is pivotally secured to the ironing roller attachment which is pivotally connected to the rear end of the frame I for vertical movement.

In order to control application of fluid to cylinder 23 and exhaust of fluid therefrom we provide an ordinary two-way valve 30 which is manually operable by means of a lever 3|. This valve 30 is connected by a line 32 to the upper end of the cylinder 23 and by a line 33 to the lower end of the cylinder. In one position of the valve fluid will flow through the line 32 into the upper and force the piston 26 downwardly, the fluid in the lower end of the cylinder exhausting through the line 33. In another position of the valve the fluid will flow through the line 33 into the lower end of the cylinder and force the fluid out of the upper end of the cylinder causingit to exhaust through the line 32. The valve 30 may be set at a neutral position.

The valve 30 is connected by a supply line 34 to a tank (not shown) which is provided on the machine containing fluid under a predetermined constant pressure. Any suitable means may be provided for maintaining the fluid in the tank under a constant predetermined pressure.

It will be apparent that when the piston 26 is forced downwardly, the piston rod 21 moves downwardly and forces the roller 4 in flrm'contact with the road surface, since downward movement of the roller is permitted because it is pivotally connected to the frame I by the links I 2 and 20. In order to limit the lowermost position of the roller 4 we provide a rod 35 which has its lower end pivoted to the lugs 29, carried by member i0, as at 36. The upper end of this rod loosea collar 31 secured to the main Above the collar 31 nuts 38 are thread- The pressure in the supply tank to which the line 34 is connected should always be the same as the downward on the roller 4.

surface. Therefore, means for maintaining a constant pressure in the supply tank should be of such a type that the constant predetermined pressure may be varwith the requirements.

It will be apparent that when the valve 30 is operated to cause downward movement of the piston 26, the ironing roller 4 will be forced in contact withthe road surface with a pressure equal to the pressure of the fluid in the supply tank. Of course this pressure cannot be greater than the effective weight of the entire machine because it would force the piston 26 downwardly formed on the memalong,

to such an extent as to raise the rear tractor rollers 3 from the road surface.

We have provided means for preventing the rear traction rollers 3 from being raised from the road surface in case the ironing roller 4 passes over an incompressible object or .high spot in the road surface. This means also serves to prevent the entire weight ofthe machine from being effective on the ironing roller 4, in case the roller passes over an incompressible object or high spot in the road. which might cause breaking down of the road structure due to the nature of the ironing roller. This means is of such a nature that the back pressure exerted on the ironing roller, or in other words the pressure tending to raise such roller, cannot exceed a predetermined amount, which may vary in accordance with different materials used for producing the road surface.

We have illustrated this device as comprising a comparatively long cylinder 39 of comparatively small cross-section which is mounted on the upper surface of the member II]. This cylinder 39 has a pair of spaced pistons 46 mounted for movement therein. Each of the pistons 40 has connected thereto a piston rod M which extends outwardly through the corresponding end of the cylinder and hasnuts 42 threaded on the portion extending from the cylinder. One of these nuts abuts the end of the cylinder. A compression spring 43 disposed within the cylinder surrounds each of the rods 4!. The pistons 40 are free to move in the cylinder but are so fitted therein that fluid is prevented from passing these pistons. The space 44 in the cylinder between the two pistons 40 is adapted to receive fluid. This fluid enters this space through a-port 45 provided midway between the ends of the cylinder 39. The port 45 is connected to the pipe 32, which is connected to the upper end of cylinder 23, by means of a flexible conduit 46.

By means of the nuts 42 the pistons 46 may be adjusted inwardly towards each other or outwardly from each other to permit the springs 43 to expand or to cause them to be compressed. The nuts 42 may be so adjusted that the springs will resist a predetermined pressure produced by fluid in the space 44. It will be apparent that the more that the springs 43 are compressed, the more resistance they will have to outward movement of the pistons 40.

In the operation of this compensating device, a predetermined pressure of fluid is applied above the piston 26 causing the roller 4 to bear upon the road surface with a predetermined pressure. The nuts 42 are then adjusted to cause the springs 43 to exert a predetermined resistance. The springs are so set that it will be necessary for a predetermined pressure to be developed in the space 44 before the pistons 46 will move outwardly away from eachv other. This pressure should be equal to the maximum pressure it. is desired to obtain on the road surface by means of the ironing roller. As the roller moves if it strikes an incompressible object or high spot, the back pressure or pressure tending to raise the ironing roller, will become excessive and will become greater than that which it is desired to apply to the road. Furthermore, there will be a tendency for the entire machine to be raised so that the traction rollers 3 will tend to move out of contact with the road surface. However, this will be prevented since the compensating device is set to limit the back pressure to a predetermined amount. When the all normal conditions of operation.

back pressura becomes excessive due to the roller 4 riding over an incompressible object or high spot, there is a tendency for the piston 26 to move upwardly in the cylinder 23. If it were not for the compensating device, this would not be permitted. However, because of the compensating device the fluid is forced through the line 32, conduit\,46 and into the space 44 and when the pressu're in ,this space exceeds a predetermined amount the pistons 40 will'move.

apart. Thus, upward movement of the ironing roller 4 will be permitted. As soon as the ironing roller passes' over the incompressible object or high spot, the springs 43 will force the pistons 40 to their original position forcing the fluid back into the upper end of the cylinder 23 and the piston 26 back to its original position.

Thus, it will be apparent that the piston 26 will always be maintained in the position to which it is moved by operation of the valve 30 and, consequently, the ironing roller 4 will always be maintained at a predetermined level. under However, if the ironing roller 4 passes over an incompressible object or high spot so that the back pressure becomes more than the pressure it is desired to apply to the road surface, the compensating device automatically operates to permit the piston 26 to move upwardly and, consequently, the roller' 4 to move upwardly relieving the excessiveback pressure. However, as soon as the roller passes over the incompressible object or high spot, the compensating device automatically operates to return piston 26 to its original position and, consequently, roller 4 to its original position.

It will be apparent that the maximum pressure applied to the road surface by the roller 4 is limited by the setting of the compensating device. If the pressure applied by the ironing roller 4 tends to become excessive and above the maximum desired, and, consequently, the back pressure becomes excessive, the compensating device automatically operates to relieve this pressure.

Thus, there is no danger of the road surface being subjected to pressure greater than a predetermined maximum. Furthermore, there is no danger of the traction rollers being raised from the road surface.

In using the entire road roller, the pressure which it is desired to apply to the road surface is selected in accordance with the particular materials being used and other conditions. This pressure is then developed in the supplytank to which the line 34 is connected. The nuts 38 on the road 35 are then set so as to limit downward movement of the ironing roller 4 to a predetermined extent, depending upon the grade it is desired to obtain. This stop mechanism is set to limit downward movement of the rollers to the predetermined grade it is desired to obtain. The nuts 42 of the compensating device are then adjusted so that the pressure to be applied by the roller 4 will be limited to a predetermined maximum which will be substantially the same as that in the supply tank. Then the lever 3| is operated to operate the value 30 to cause fluid to be supplied above the piston 26 in cylinder 23 and to be exhausted from beneath the piston. The fluid in the upper end of the cylinder always tends to force the piston 26 downwardly because the upper surface of the piston is of greater area than the lower surface thereof. This forces the ironing roller 4 into contact with the road surface and will press it against the road surface with a pre- I when the ironing roller passes over an incompressible object orhigh spot, the compensating device servesto relieve excessive back pressure so that the pressure exerted by the ironing roller 4 is limited to a predetermined maximum. Thus, breaking down of the road structure is prevented and movement of the traction rollers 3 out oi.

contact with the road surface is prevented.

When it is' desired to raise the ironing roller into inoperative position, the valve 30 is reversed so that fluid will be supplied below the piston 26 and exhausted from above it, permitting upward movement of the piston and, consequently, of the ironing roller. This upward movement will be comparatively fast because the cross-sectional area of the space in the lower end of the cylinder to be filled with fluid is comparatively small.

It will be apparent from the above that we have provided a road roller which is provided with an ironing roller of such a nature that the irregularities in the road surface will be effectively ironed out with the result that a very smooth road surface will be obtained. The fluid means which operates the ironing rollers is of such a nature that the pressure applied to the road surface by it may be varied. Furthermore, the compensating device serves to prevent an excessive amount of pressure being exerted on" the road structure or the traction rollers being forced out of contact with the road surface when the ironing roller passes over an incompressible object or a high spot. In using our device, the ironing roller can be set to obtain the proper grade and this grade can be obtained in one pass over the material. The pressure which it is desired to exert on the road material varies with different materials. The compensating device on our machine may be set to limit the pressure to a predetermined maximum suitable for the particular material.

Although we prefer that the ironing roller be located at the rear end of the machine, it will be apparent that our invention is not necessarily limited thereto.

Although we have specified herein that we provide an ironing roller on the road roller, it is apparent that a scarifler or other member might be substituted for the ironing roller 4 of our attachment. The other mechanism would remain the same. Thus, if the scarifler contacted with a large stone or boulder, the compensating device would permit upward movement thereof. In the claims where we specify an ironing roller, we intend to cover other members which might be substituted therefor.

Many other advantages will be apparent from the preceding description, the drawings and the following claims.

Having thus described our invention, what we claim is:

1. In a device of the type described, a supporting structure mounted for movement along a road surface, an ironing roller mounted on said supporting structure in such a manner that it may move vertically, non-compressible fluid-actuated means for forcing said ironing roller downwardly into contact with the road surface with a predetermined pressure, and means for automatically relieving the downward pressure exerted by said ironing roller on said road surface whenever it tends to exceed said predetermined pressure.

2. In a device of the type described, a supporting structure mounted for movement along a road surface, an ironing roller mounted'on said supporting structure in such a manner that it may move vertically, non-compressible fluid-actuated means for forcing said roller downwardly into contact with the road surface, and means for permitting upward movement of roller when the back pressure exerted thereon exceeds a predetermined maximum, said last-named means serving to return said ironing roller automatically to its original position when the back pressure exerted thereon falls to the said predetermined maximum.

3; In a device of the type described, a supporting structure mounted for movement along a road surface, an ironing roller mounted on said supporting structure, in such a manner that it may move vertically, non-compressible fluid-actuated means for normally forcing said roller downwardly into contact with the road surface, and means for automatically permitting upward movement of said ironing roller when the back pressure exerted thereon exceeds a predetermined maximum, said last-named means serving to return said ironing roller automatically to its original position when the back pressure exerted thereon falls to the said predetermined maximum, said last-named means being adjustable so that the said predetermined maximum may be varied.

4. In a device of the type described, a supporting structure mounted for movement along a road surface, an ironing roller mounted on said supporting structure in such a manner that it may move vertically, non-compressible fluid-actuated means for forcing said roller downwardly into contact with the road surface, and non-compressible fluid-actuated means for automatically permitting upward movement of said ironing roller when the back pressure exerted thereon exceeds a predetermined maximum, said last-named means serving to return said ironing roller automatically to its original position when the back pressure exerted thereon falls to the said predetermined maximum.

5. In a device of the type described, a supporting structure mounted for movement along a road surface, an ironing roller mounted on said supporting structure in such a manner that it may move vertically, non-compressible fluid-actuated means for forcing said roller downwardly into contact with the road surface, and noncompressible fluid-actuated means for automatically permitting upward movement of said ironing roller when the back pressure exerted thereon exceeds a predetermined maximum, said lastnamed means serving to return said ironing roller automatically to its original position when the back pressure exerted thereon falls to the said predetermined maximum, said last-named means being adjustable so that the said predetermined maximum may be varied.

6. In a device of the type described, a supporting structure mounted for movement along a road surface, an ironing roller mounted on said supporting structure in such a manner that it may move vertically, non-compressible fluidactuated means for forcing said roller downwardly into contact with the road surface; said means comprising cylinder and piston mechanism connected to said supporting structure and to said ironing roller, and non-compressible fluid-actuated means for permitting upward movement of said ironing roller when the back pressure exerted thereon exceeds a predetermined maximum, said last-named means comprising cylinder and piston mechanism and being ad- Justa'ble to vary said predetermined maximum.

'1. In a device of the type described, a supporting structure mounted for movement along a road surface, an ironing roller mounted on said supporting structure in such a manner that it may move vertically, non-compressiblefiuidfor forcing said roller downwardly into contact with the road surface with a predetermined pressure, and non-compressible fluid-actuated means for automatically permitting upward movement of said ironing roller when the pressure exerted by it on the road surface exceeds said predetermined pressure.

8. In a device of the type described, a supporting member mounted for movement along a road surface. an ironing roller member mounted on said supporting member in such a manner that it may move vertically, non-compressible fluidactuated means for forcing said roller member downwardly into contact with the road surface, said means comprising a cylinder connected to one of said members and a piston connected to the other of said members, and non-compressible fluid-actuated means for permitting upward movement of said ironing roller when the back pressure exerted thereon exceeds a predetermined maximum, said last-named means comprising a cylinder connected to one end of the first-named cylinder, said last-named cylinder having a piston therein, and means of pre-selected resisting power normally tending to prevent movement of said piston.

9. In a device of the type described, a supporting structure mounted for movement along a road surface, an ironing roller mounted on said supporting structure in such a manner that it may move vertically, non-compressible fluidactuated means for forcing said roller downwardly into contact with the road. surface, said means comprising a cylinder mounted on said supporting structure and a piston having a rod extending downwardly through the lower end of said cylinder and being connected to said ironing roller, means for supplying non-compressible fluid to said cylinder above said piston, and noncompressible fluid-actuated means for permitting upward movement of said ironing roller when the back pressure exerted thereon exceeds a predetermined maxim said last-named means comprising a cylinder having a port intermediate its ends which is connected to the upper end of said first-named cylinder, said last-named cylinder having a pair of pistons therein disposed on opposite sides of said port, and means of preselected resisting power for resisting movement of said pistons away from each other.

10. In a device of the type described, a supporting structure mounted for movement along a road surface, an ironing roller mounted on said supporting structure in such a manner that it may move vertically, non-compressible fluidactuated means for forcing said roller downwardly into contact with the road surface, said means comprising a cylinder mounted on said supporting structure and a piston-having a rod extending downwardly through the lower end of said cylinder and being connected to said ironing roller, means for supplying non-compressible fluid to said cylinder above said piston, and noncompressible fluid-actuated means for permitting upward movement of said ironing roller when the back pressure exerted thereon exceeds a predetermined maximum, said last-named means comprising a cylinder having a port intermediate its ends which is connected to the upper end of said first-namedcylinder, said lastnamed cylinder having a pair of pistons therein disposed on opposite sides of said port, and a compression spring of predetermined resisting power disposed in each end of said cylinder between one of said pistons and the corresponding end of the cylinder.

11. In a device of the type .described, a supporting structure mounted for movement along a road surface, an ironing roller mounted on said supporting structure in such a manner that it may move vertically, non-compressible fluidactuated means for forcing said roller downwardly into contact with the road surface, said means comprising a cylinder mounted on said supporting structure and a piston having a rod extending downwardly through the lower end of said cylinder and being connected to said ironing roller, means for supplying the non-compressiblefluid to said cylinder above said piston, and non-compressible fluid-actuated means for permitting upward movement of said ironing roller when the back pressure exerted thereon exceeds a predetermined maximum, said lastnamed. means comprisinga cylinder having a port intermediate its ends which is connected to the upper end of last-named cylinder having a pair of pistons therein disposed on opposite sides of said port, each of said pistons having a piston rod extending outwardly through the corresponding end of said cylinder, a surrounding relation to each of said piston rods and being located between the piston and the corresponding end of the cylinder, each of said rods having a nut threaded on the portion thereof extending compression spring may be compressed to any desired amount to vary the resistance thereof.

12. In a device of the type described, a supporting structure mounted for movement along a road surface, an ironing roller mounted on said supporting structure in such a manner that it may move vertically, non-compressible fluidactuated means for forcing said roller downwardly into contact with the road surface with a predetermined pressure, other means for limiting the extent of downward movement of said ironing roller, and non-compressible fluid actuated means for automatically permitting upward movement of said ironing roller when the back pressure exerted thereon exceeds said predetermined pressure. I

13. In a device of the type described, a supporting structure mounted for movement along a road surface, an ironing roller mounted on said supporting structure in such a manner that it may move vertically, non-compressible fluidactuated means for forcing said roller downwardly into contact with the road surface with a predetermined pressure, adjustable means for limiting the extent of downward movement of said ironing roller, and non-compressible fluidactuated means for automatically permitting upward movement of said ironing roller when the said first-named cylinder, saidfrom the cylinder so that the" compression spring disposed in back pressure exerted thereon exceed. preternuned Dream-e. and non-compressible 'flulddetermined 1: actuated menu for an M11! Permit up- 14. A road roller comprising a main frame :upward movement of sold Ironing roller' when the ported by front and rear rollers. an ironing roller back me exerted thereon exceeda laid premounted on the rear end of said frame, behind determined pressure.

the rear rollers in such a manner that It may cmmoab A. ownns. move vertically, non-compressible fluid-actuated mm L. Wm. mean for tot-cm: said lronlnz roller downwardly IARL I. BIICHER; Into contact with the road Iurtace with a prede-'