US3662658A

US3662658A - Impact compaction of loose materials

Info

Publication number: US3662658A
Application number: US21016A
Authority: US
Inventors: Aubrey Ralph Berrange
Original assignee: South African Inventions Development Corp
Current assignee: South African Inventions Development Corp
Priority date: 1969-04-02
Filing date: 1970-03-19
Publication date: 1972-05-16
Anticipated expiration: 1989-05-16
Also published as: FR2038168A1; BR7017970D0

Abstract

The specification discloses an impact roller which is attachable to a hauling vehicle via a drawbar and a resilient coupling and which includes restraining means, for example in the form of damping means or braking means, to restrain excessive relative horizontal movement between the roller and the drawbar during hauling of the roller.

Description

United States Patent Berrange [451 May 16,1972

IMPACT COMPACTION OF LOOSE MATERIALS Aubrey Ralph Berrange, Pretoria, South Inventor:

Africa Assignee: South African Inventions Development Corporation, Pretoria, South Africa Filed: Mar. 19, 1970 Appl.No.: 21,016

Foreign Application Priority Data [56] References Cited UNITED STATES PATENTS 2,909,106 10/1959 Berrange ..94/48 Primary Examiner.lacob L. Nackenofi- Attorney-Karl W. F locks 57 ABSTRACT The specification discloses an impact roller which is attachable to a hauling vehicle via a drawbar and a resilient coupling and which includes restraining means, for example in the form Apr. 2, 1969 South Africa ..69/2360 of damping means or braking means to restrain excemve relative horizontal movement between the roller and the US. Cl ..94/48, 94/50 drawbar during hauling of the m Int. Cl v ..E0lc 19/30 Field of Search "94/50, 48 16 Claims, 5 Drawing figures 56 u a u I; 54

PHENTEnm 1s m:

SHEET 3 OF 3 HEN:

IMPACT COMPACTION OF LOOSE MATERIALS BACKGROUND OF THE INVENTION This invention relates to impact compaction of layers of soils and gravels. More particularly the invention relates to control means for controlling the movement of an impact roller, to an improved impact roller and to a method of controlling the movement of such a roller.

Impact rollers are rollers suitable for the compaction of materials such as soils, gravels and the like by employing impact forces generated when such a roller is hauled across a surface.

In this specification an impact roller is to be understood as including a roller having a profile of a non-circular multilobed cross-section. When such a roller is hauled across a surface, it rotates, thereby causing the center of gravity of the roller to rise and fall. The vertical distance of rise or fall is known as the lift of the roller. During the fall of the center of gravity of the roller under gravitational force, impact is delivered to the underlying material in the surface below the roller, thereby causing the material to be compacted.

The closest prior art known to the applicant is US. Pat. No. 2,909,106.

SUMMARY OF THE INVENTION According to the invention there is provided control means for controlling the movement of an impact roller which is attachable to a hauling vehicle via a drawbar and a resilient coupling arranged to permit relative horizontal movement between the roller and the drawbar, the control means including restraining means operable between the roller and the drawbar to restrain relative horizontal movement between the roller and the drawbar.

Conveniently, the restraining means may be arranged to restrain relative horizontal movement between the roller and the drawbar exceeding one-fourth to three-fourths of the lift of the roller.

If desired, the restraining means may be arranged to permit substantially unrestrained horizontal movement between the roller and the drawbar, except for the influence of the resilient coupling, when the relative horizontal movement is less than one-fourth to three-fourths of the lift of the roller.

The substantially unrestrained horizontal movement may be effected by providing a lost motion coupling in the restraining means to permit initial lost motion before the restraining means becomes effective.

The restraining means may in one form be arranged to damp relative horizontal movement between the roller and the drawbar. In this arrangement, the restraining means may include a plunger and cylinder assembly attachable between the roller and the drawbar, the plunger being arranged to partition the cylinder into two chambers and to be displaced in the cylinder by relative movement between the roller and the drawbar to displace a fluid under pressure from one chamber of the cylinder to the other via a restricted orifice to damp the movement of the plunger in the cylinder.

In another form, the restraining means may be arranged to brake relative horizontal movement between the roller and the drawbar. In this arrangement, the restraining means may include a cam and follower arrangement, and a master cylinder and a slave cylinder interconnected by a fluid line, the follower being arranged to actuate the master cylinder, and the slave cylinder being arranged to actuate a brake.

Further according to the invention there is provided an impact roller including a roller, a drawbar for attachment to a hauling vehicle, a resilient coupling between the drawbar and the roller to permit relative movement between the roller and the drawbar, and restraining means operable between the roller and the drawbar to restrain relative horizontal movement between the roller and the drawbar.

The roller may be rotatably mounted in or on the drawbar via an articulated joint to permit rotation of the roller about a rotational axis.

Conveniently, the rotatable mounting of the roller may be arranged to have a mid-operating position ahead of the articulated joint in the direction of forward travel of the roller when the resilient coupling is substantially in equilibrium with the roller during hauling of the roller. In this arrangement, the restraining means may be arranged to restrain relative horizontal movement between the roller and the drawbar when the horizontal movement fore and aft of the mid-operating position exceeds one-fourth to three-fourths of the lift of the roller.

In one form, the restraining means may be arranged to damp relative horizontal movement between the roller and the drawbar. In this arrangement the restraining means may include a plunger and cylinder assembly between the drawbar and the roller, the plunger being arranged to partition the cylinder into two chambers and to be displaced in the cylinder by relative movement between the roller and the drawbar to displace a fluid under pressure from one chamber of the cylinder to the other via a restricted orifice to damp the movement of the plunger in the cylinder.

Further in this form, there may be included a bell crank pivotally interconnecting the articulated joint, the roller at its rotatable mounting and one end of a plunger rod having at its other end the plunger, the cylinder being pivotally mounted on the drawbar. The bell crank may be arranged to permit the plunger to obtain a top dead center position in the cylinder when the rotatable mounting of the roller is in its mid-operating position ahead of the articulated joint.

If desired, the substantially unrestrained horizontal movement over the predetermined range may be effected by providing a lost motion coupling in the restraining means to permit initial lost motion before the restraining means becomes effective.

The resilient coupling may be provided inside the cylinder of the restraining means to form a unitary arrangement therewith, or it may be provided as a unit separated from the restraining means.

In another form, the restraining means may be arranged to brake relative horizontal movement between the roller and the drawbar. In this form, the restraining means may include a cam and follower arrangement, and a master cylinder and a slave cylinder interconnected by a fluid line, the follower being arranged to actuate the master cylinder, and the slave cylinder being arranged to actuate a brake.

The invention is now described by way of an example with reference to the accompanying drawings, in which:

FIG. 1 shows a side view, partly in section, of an impact roller including one embodiment of an hydraulic damping arrangement;

FIG. 2 shows a plan view, partly in section, of the roller shown in FIG. 1;

FIG. 3 shows a view similar to FIG. 1 but with the roller including another embodiment of an hydraulic damping arrangement;

FIG. 4 shows yet another embodiment of an hydraulic damping arrangement suitable for use on the roller shown in FIG. 1; and

FIG. 5 shows the impact roller of FIG. 1 with an hydraulic braking arrangement.

Referring generally to FIGS. 1, 2 and 3 of the drawings, reference numeral 10 indicates generally an impact roller including a roller 12 of a non-circular cross-sectional profile. The roller 12 has an axle 14 passing through its center of gravity 16.

The non-circular cross-sectional profile of the roller 12 includes four rounded lobes 18 which cause the center of gravity 16 of the roller to intermittently rise and fall a distance (R-r) when the roller is hauled over the surface 20 to rotate in the direction of arrow 22. The falling of the center of gravity delivers an impact to the surface 20, thereby causing compaction of the material underlying the surface 20. As there are four lobes 18 on the roller, four blows are delivered during each revolution of the roller 12.

The roller axle 14 is attached to a drawbar 24 via bearings 26, traction rods 28 secured to the bearings 26, and a resilient coupling comprising a pair of leaf springs 30 secured at 32 to the drawbar 24 and via bolts 34 to the traction rods 28. The drawbar 24 has a beam 36 on the end of which may be secured a universal coupling for attachment to a hauling vehicle such as a tractor. It will be seen that during hauling, traction force is transmitted from the drawbar 24 via the springs 30, the bolts 34, the traction rods 28 and the bearings 26 to the roller axle 14.

The drawbar 24 has two arms 40 extending rearwardly away from the drawbar on either side of the roller 12 so that the roller is positioned between the arms. The end of each arm 40 vided a cylinder 46 and a plunger 48. Each cylinder 46 is pivotally connected to each arm 40 by means of a pin 50 and a bracket 52. The plunger 48 is mounted on a plunger rod 54 which is pivotally connected to the bell crank 42 by means of a pin 56 to be reciprocable in the cylinder 46.

The function of the plunger 48 and cylinder 46 is to restrain excessive relative movement between the drawbar 24 and the roller 14 exceeding predetermined limits by means of hydraulic damping.

The relative positions of the axle l4 and the pins 44 and 56 are so arranged that when the

ins

44, 56 and 50 are all in line, the plunger 48 reaches a top dead center position in the cylinder 46. In this position the plunger 48 can only be displaced from right to left in the cylinder 46.

During normal operation of the roller 10, when the roller is being hauled at a constant optimum speed in the direction of arrow 55 and the roller 12 rotates in the direction of arrow 22, a state of substantial equilibrium is reached between the springs 30 and the drag caused by the mass of the roller 12. The optimum speed depends upon such factors as the mass of the roller, the number of lobes on the roller and the resilience of the springs 30. In this position of equilibrium the roller axle 14 is disposed between the pin 44 and the drawbar 24 and the plunger 48 is in its top dead center position in the cylinder 46. An imaginary line 57 extending through the pin 44 and the axle 14 in this position can be regarded as the mid-operating position of the axle 14.

As soon as the hauling vehicle accelerates or decelerates, the inertia of the roller 12 causes relative movement to take place between the roller axle l4 and the drawbar 24, i.e., the roller either lags behind or overruns the drawbar. This relative movement is normally essential for the operation of the roller, but is undesirable when it becomes excessive under certain circumstances, particularly at slow speeds. These circumstances arise when the stored energy in the spring 30 which tends to rotate the roller 12 in the direction of the arrow 22 is just insufficient to pull the roller 12 over when it passes over a lobe 18. The roller then drops back in a direction opposite to arrow 22 and as the hauling vehicle is still moving forward in the direction of arrow 55, the roller and the hauling vehicle are momentarily moving in opposite directions, thereby causing a considerable relative movement between the roller and the drawbar 24. The relative movement is accompanied by a shock force which may result in damage to the roller structure and cause wasteful dissipation of energy. The function of the plunger 48 and the cylinder 46 is to restrain these large relative movements and thereby to dampen the accompanying shock forces.

rai

When a large relative movement occurs between the roller 12 and the drawbar 24, the axle 14 is displaced from its midoperating position on the line 57. Displacement takes place along a circular are 59 having its center of curvature on the axis of the pin 44. Displacement of the axle 14 along the arch 59 can be in a clockwise or counterclockwise direction. Whether the displacement of the axle 14 from its mid-operating position on the line 57 is in clockwise or counterclockwise direction, the arrangement as before described is such that the plunger 48 is displaced from right to left in the cylinder 46.

Referring now in particular to FIG. 1, the piston 48 partitions the cylinder 46 into two chambers 58 and 60 which are filled with an hydraulic fluid and which are in a closed hydraulic circuit with one another via

fluid lines

62 and 64. In the

fluid lines

62 and 64 are provided devices 66 and 68 which permit unrestricted fluid flow in the directions of the arrows but restricted flow in the opposite directions. A branch line 70 leads into an hydraulic fluid reservoir 72 for accommodating and for making up fluid flow from and to the chambers 58 and 60.

The plunger rod 54 has a shank 74 of a reduced cross-section for fitting in a bore through the plunger 48. The plunger 48 is secured on the shank 74 between the plunger rod 54 and a nut 76. The spacing between the nut 76 and the plunger rod 54 is such that some lost motion of the plunger 48 is permitted on the shank 74 and the extent of the lost motion can be ad justed by the nut 76. The effect of the lost motion is that a certain amount of substantially free movement is pennitted between the drawbar anns 40 and the roller 12 via the axle 14 and the plunger rod 54 before the plunger 48 is displaced.

When the plunger 48 is displaced in the cylinder 46, it displaces hydraulic fluid from one of the chambers 58 or 60 to the other via the devices 66 and 68. Fluid flow through these devices against the direction of the arrows is restricted, and consequently the movement of the plunger 48 in the cylinder 46 is restrained. In this manner, relative movement between the roller 12 and the drawbar 24 is damped.

Thus, while the lost motion effected by the shank 74 in the plunger 48 permits minor undamped relative horizontal movement between the roller 12 and the drawbar 24, major relative horizontal movements are damped.

In the arrangement shown in FIG. 1, the roller axle 14 is in its mid-operating position on the line 57 and the plunger 48 is in its top dead center position in the cylinder 46. Consequently, the plunger rod 54 will be displaced from right to left in the cylinder 46 regardless of whether the axle 14 is displaced clockwise or counterclockwise along the are 59.

Whenever the axle 14 is displaced along the are 59 from its mid-operating position on line 57, it will move substantially unrestrained until the lost motion of the shank 74 in the plunger 48 is exhausted. As soon as the nut 76 abuts the plunger 48, damping commences. The angle of unrestrained movement of the axle 14 along the are 59 on either side of its mid-operating position is shown by reference numeral 78. The horizontal component of the portion of are 59 intersected by twice angle 78 is shown by H. In other words, H represents the limits of substantially unrestrained horizontal movement between the roller 12 and the drawbar 24. Relative movements between the roller and the drawbar exceeding these limits are damped.

Referring now in particular to FIG. 3, there is shown another arrangement for effecting hydraulic damping of relative horizontal movement between the roller 12 and the drawbar 24. The drawing shows an arrangement of chambers 58, 60 and 62.1 and ports 64.1, 66.1, 68.1 and 70.1 in the cylinder 46, and a passage 72.1 interconnecting the ports. The chambers 58 and 60 are filled with an hydraulic fluid, and the chamber 62.1 is partly filled with an hydraulic fluid and with a gas under pressure.

The ports 66.1, 68.1 and 70.1 are comparatively large in size in relation to the port 64.1 to permit unrestrained displacement of hydraulic fluid through these ports. The port 64.1 is a restricted orifice to retard the fluid flow through this port to restrain the axial displacement of the plunger 48 in the cylinder 46.

When the plunger 48 is between the ports 66.1 and 68.1, fluid can be displaced unrestrictedly between the chambers 58 and 60 via the ports 66.1 and 68.1 and the passage 72.1 during small reciprocations of the piston in the cylinder. Thus the movement of the piston in the cylinder is unrestrained as long as the piston is between the ports 66.1 and 68.1.

During a large relative movement between the drawbar 24 and the axle 14, the piston 48 is displaced beyond the limits of ports 66.1 and 68.1. When the piston is displaced over port 66.1 towards the left as shown in FIG. 3, fluid is displaced from the chamber 58 via the restricted port 64.1, the passage 72.1 and the port 68.1 to chamber 60. In view of the restricted fluid flow through the port 64.1, the movement of the piston 48 in the cylinder 46 is restrained and thereby the movement of the roller 12 relative to the drawbar 24 is clamped.

The difference in volumes of fluid in the chambers 58 and 60 due to the volume occupied by the plunger rod 54 is accommodated by displacement into and out of the chamber 62.1 via port 70.1.

When the axle 14 is in its mid-operating position on line 57, the plunger 48 is in its top dead center position in the cylinder 46 between the ports 66.1 and 68.1. As already described, the plunger can move unrestrictedly in the cylinder 46 when it is between the ports 66.1 and 68.1, i.e., the minor movements of the plunger are not restrained. By being in its top dead center position the plunger 48 can only move from right to left in the cylinder 46 and therefore never move over the port 68.1.

The arrangement of the ports 64.1, 66.1 and 68.1 is such that the axle 14 can move unrestrained along the are 59 for an angle 78 on either side of its mid-operating position on line 57. The portion of are 59 intersected by twice angles 78 has a horizontal component H. In other words, H represents the limits of substantially unrestrained horizontal movement between the roller 12 and the drawbar 24. Outside these limits the plunger 48 moves over the port 66.1 towards the port 64.1 and its movement is restrained.

Referring now to FIG. 4 of the drawings, there is shown another hydraulic damping arrangement 80 for use with the impact roller shown in FIG. 1. The arrangement 80 is a combination in a single unit of the damping piston and cylinder arrangement and the resilient coupling indicated in FIG. 1 by

reference numerals

48, 46 and 30.

The arrangement 80 is pivotally secured between the drawbar 24 and the roller axle 14 of FIG. 1 by means of a bracket 82, a plunger rod 84 and a link 86 pivotally secured to the drawbar arm 40. On the plunger rod 84 is mounted a plunger 88 which is axially displaceable in a cylinder 90 in which it fits sealingly and which it divides into two sealed chambers 92 and A compression spring 96 is mounted inside the chamber 92, and in addition the chamber is filled with a gas. When the plunger 88 is displaced from right to left, it compresses the gas in the chamber 92 and in addition compresses the spring 96. The compressed gas and the compressed spring 96 form a resilient coupling between the roller axle l4 and the drawbar 24.

In the cylinder 90 there are provided two

further chambers

98 and 100 which are filled with an hydraulic fluid and which are in a closed hydraulic circuit with each other via an hydraulic line 102. Two

pistons

104 and 106 are slidably mounted on the plunger rod 84 to be sealingly displaceable into and out of the

chambers

98 and 100. The relative axial positions of the

pistons

104 and 106 on the plunger rod 84 can be adjusted by screwing a plug 108 into or out of an hydraulic fluid reservoir 1 10.

The operation of arrangement 80 is as follows: During minor relative movements between the roller axle 14 and the drawbar 24, the plunger 88 is axially displaced in the cylinder 90 against the compression of the gas in the chamber 96 and the compression of the spring 96. The plunger 88 under these conditions is displaced substantially unrestrained in the cylinder 90. As soon as the plunger 88 abuts the piston 104, further displacement of the plunger causes hydraulic fluid to be displaced from the chamber 98 via the line 102 to the chamber 100. In view of a restricted passage through the line 102, fluid flow through the line is retarded and consequently the displacement of the plunger 88 in the cylinder is damped. Fluid which is displaced from the chamber 98 to chamber displaces the piston 106 from right to left along the plunger rod 84.

It will be seen from the drawing that the displacement of the plunger 88 in the cylinder 90 is substantially unrestrained between the

pistons

104 and 106, and these limits are indicated by H. Outside these limits the axial displacement of the plunger 88 in the cylinder 90 is clamped and therefore relative movement between the roller axle 14 and the drawbar arm 40 causing such a displacement is restrained.

Referring now to FIG. 5 of the drawings, there is shown a braking arrangement 112 for restraining relative horizontal movement between the axle 14 of roller 12 shown in FIG. 1 and the drawbar 24. The axle 14 is pivotally secured to the drawbar arm 40 by means of a link 114 which has a cranked stub axle 116. The stub axle 116 fits rotatably in a bush 118 secured to the drawbar arm 40. A carrier 120 is fast with the stub axle 1 16.

The carrier 120 has two arcuately spaced

cams

122 and 124 whose relative arcuate positions on the carrier 120 are adjustable by means of

bolts

126 and 128 extending through

arcuate slots

130 and 132. A follower 134 co-operates with the

cams

122 and 124 and is arranged to actuate an hydraulic fluid in a master cylinder 136. The master cylinder 136 via a line 138 and a slave cylinder 140 actuates a piston 142 to which is attached a brake block 144. When actuated, the brake block 144 abuts a brake drum 146 provided on the carrier 120 and brakes it frictionally.

Between the drawbar 24 and the axle 14 is provided a resilient coupling in the from of a spring 148 to transmit traction force from the drawbar 24 to the roller axle 14 when the drawbar is pulled in the direction of arrow 150. The roller 12 will then rotate in the direction of arrow 152.

When there is relative horizontal movement between the drawbar 24 and the roller axle 14, the axle 14 is displaced along the are 59 (arc 59 is described in more detail with reference to FIG. 1) about the crank 116. In other words, the stub axle 116 rotates in the bush 118, as a result of which the carrier 120 is rotated. The carrier 120 can rotate between the limits of

cams

122 and 124 i.e., through an angle 154, without actuating the follower 134. Rotation of the carrier 120 exceeding these limits will actuate the follower 134 and thereby the brake block 144, whereby the carrier 120 will be braked and relative movement between the roller axle 14 and the drawbar 24 will be restrained.

Consequently, substantially unrestrained horizontal movement between the roller axle l4 and the drawbar 24 will be permitted as long as the movement is such that the rotation of the carrier 120 is confined within the limits indicated above i.e., so that the follower 134 is not actuated.

The

cams

122 and 124 are arcuately spaced from one another by the angle 154 which is equal to twice the angle 78. Please refer to FIG. 1 for the description of angle 78 and line 57. Twice the angle 78 may be translated into a horizontal component H. In other words, H represents the limits of substantially unrestrained movement between the drawbar 24 and the roller axle 14 before the

brake parts

144 and 146 are actuated.

The impact delivered to the material underlying the surface 20 is dependent inter alia upon the lift of the center of gravity 16 i.e., the distance (R-r). In order to affect the impact delivered as little as possible, the distance H of unrestrained movement shown in FIGS. 1, 3, 4 and 5, should be as large as possible. But the distance H should not be too large, otherwise only an exceptional relative movement between the roller axle 14 and the drawbar 24 will be restrained. It is a practical problem to decide what the distance H should be. In practice it has been found that satisfactory results can be obtained by making the distance H roughly equal to one-half of the lift of the roller i.e., H k (R-r), although it may vary from oneforth to three-fourths of the lift of the roller.

What i claim is:

1. Control means for controlling the movement of an impact roller having a non-circular multi-lobe profile to obtain intermittent lift which is attachable to a hauling vehicle, traction rod means operatively connected at one end to bearing means for said roller and connected at the other end to resilient means which are operatively connected to a drawbar to provide a resilient coupling therebetween and to permit relative horizontal movement between the roller and the drawbar, the control means including restraining means pivotally connected to the roller and the drawbar and operable by fluid pressure to restrain relative horizontal movement between the roller and the drawbar exceeding one-fourth to three-fourths of the lift of the roller.

2. Control means according to claim 1, in which the restraining means includes a lost motioncoupling constituted by a plunger member slidably mounted on a plunger rod between spaced apart abutment portions thereon in a cylinder to permit substantially unrestrained horizontal movement between the roller and the drawbar, except for the influence of the resilient coupling when the relative horizontal movement is less than one-fourth to three-fourths of the lift of the roller, and said unrestrained horizontal movement is efiected in said lost motion coupling before the restraining means becomes effective.

3. Control means according to claim 1, in which the restraining means includes a plunger and cylinder assembly attached between the roller and the drawbar to damp relative horizontal movement therebetween, by action of the plunger which is arranged to partition the cylinder into two chambers and to be displaced in the cylinder by relative movement between the roller and the drawbar to displace a fluid under pressure from one chamber of the cylinder to the other via a restricted orifice to damp the movement of the plunger in the cylinder.

4. An impact roller assembly having a non-circular multilobed profile to obtain intermittent lift including a roller, traction rod means operatively connected at one end to bearing means for said roller and connected at the other end to resilient means which are operatively connected to a drawbar for attachment to a hauling vehicle, to provide a resilient coupling between the drawbar and the roller to permit relative horizontal movement between the roller and the drawbar, and restraining means pivotally connected to the roller and the drawbar by fluid pressure to restrain relative horizontal movement between the roller and the drawbar exceeding onefourth to three-fourths of the lift of the roller.

5. An impact roller assembly according to claim 4, in which the roller is rotatably mounted on the drawbar via an articulated joint to permit rotation of the roller about a rotational axis.

6. An impact roller assembly according to claim 5, in which the rotatable mounting of the roller includes a mid-operating position ahead of the articulated joint in the direction of forward travel of the roller when the resilient coupling is substantially in equilibrium with the roller during hauling of the roller and in which said restraining means restrains relative horizontal movement between the roller and the drawbar when the horizontal movement fore and aft of the mid-operating position exceeds one-fourth to three-fourths of the lift of the roller.

7. An impact roller assembly according to claim 4, in which the restraining means includes a lost motion coupling constituted by a plunger member slidably mounted on a plunger rod between spaced apart abutment portions thereon in a cylinder to permit substantially unrestrained horizontal movement between the roller and the drawbar, except for the influence of the resilient coupling, when the relative horizontal movement is less than one-fourth to three-fourths of the lift of I amthe roller, and said unrestrained horizontal movement is effected in said lost motion coupling before the restraining means becomes efi'ective.

8. An impact roller assembly according to claim 4, in which the restraining means comprises damping means to damp relative horizontal movement between the roller and the drawbar.

9. An impact roller assembly having a non-circular multilobed profile to obtain intennittent lift including a roller, traction rod means operatively connected at one end to bearing means for said roller and connected at the other end to resilient means which are operatively connected to a drawbar for attachment to a hauling vehicle, to provide a resilient coupling between the drawbar and the roller to permit relative horizontal movement between the roller and the drawbar, and damping means operable between the roller and the drawbar to damp relative horizontal movement between the roller and the drawbar exceeding one-fourth to three-fourths of the lift of the roller, the damping means including a plunger and cylinder assembly pivotally connected between the drawbar and the roller, the plunger being arranged to partition the cylinder into two chambers and to be displaced in the cylinder by relative movement between the roller and the drawbar to displace a fluid under pressure from one chamber of the cylinder to the other via a restricted orifice to damp the movement of the plunger in the cylinder.

10. An impact roller assembly according to claim 9, which includes a bell crank pivotally interconnecting the articulated joint, the roller at its rotatable mounting and one end of a plunger rod having at its other end the plunger, the cylinder being pivotally mounted on the drawbar.

11 An impact roller assembly according to claim 10, in which the bell crank is so constructed that the plunger obtains a top dead center position in the cylinder when the rotatable mounting of the roller is in its mid-operating position ahead of the articulated joint.

12. An impact roller according to claim 9, in which the resilient coupling is provided inside the cylinder of the damping means.

13. Control means for controlling the movement of an impact roller having a non-circular multi-lobed profile to obtain intermittent lift which is attachable to a hauling vehicle, traction rod means operatively connected at one end to bearing means for said roller and connected at the other end to resilient means which are operatively connected to a drawbar to provide a resilient coupling therebetween to permit relative horizontal movement between the roller and the drawbar, the control means including frictional restraining means comprising brake means operable between the roller and the drawbar to frictionally restrain'relative horizontal movement between the roller and the drawbar exceeding one-fourth to threefourths of the lift of the roller.

14. Control means for controlling the movement of an impact roller having a non-circular multi-lobed profile to obtain intermittent lift which is attachable to a hauling vehicle, traction rod means operatively connected at one end to bearing means for said roller and connected at the other end to resilient means which are operatively connected to a drawbar to provide a resilient coupling therebetween to permit relative horizontal movement between the roller and the drawbar, the control means including brake means operable between the roller and the drawbar to brake relative horizontal movement between the roller and the drawbar exceeding one-fourth to three-fourths of the lift of the roller, the brake means including a brake member, a cam and follower arrangement and a master cylinder and a slave cylinder interconnected by a fluid line, the follower being arranged to actuate the master cylinder and the slave cylinder being arranged to actuate the brake member 15. An impact roller assembly having a non-circular multilobe profile to obtain intermittent lift including a roller, traction rod means operatively connected at one end to hearing means for said roller and connected at the other end to resilient means which are operatively connected to a drawbar for attachment to a hauling vehicle, to provide a resilient coupling between the drawbar and the roller to permit relative horizontal movement between the roller and the drawbar, and frictional restraining means operable between the roller and the drawbar to frictionally restrain relative horizontal movement between the roller and the drawbar exceeding onefourth to three-fourths of the lift of the roller, said restraining means comprising brake means for braking relative horizontal movement between the roller and the drawbar.

16. An impact roller assembly having a non-circular multilobed profile to obtain intermittent lift including a roller, traction rod means operatively connected at one end to bearing means for said roller and connected at the other end to resilient means which are operatively connected to a drawbar for attachment to a hauling vehicle, to provide a resilient coupling between the drawbar and the roller to permit relative horizontal movement between the roller and the drawbar, and brake means operable between the roller and the drawbar to brake relative horizontal movement between the roller and the drawbar exceeding one-fourth to three-fourths of the lift of the roller, the brake means including a brake member, a cam and follower arrangement and a master cylinder and a slave cylinder interconnected by a fluid line, the follower being arranged to actuate the master cylinder and the slave cylinder being arranged to actuate the brake member.

Claims

2. Control means according to claim 1, in which the restraining means includes a lost motion coupling constituted by a plunger member slidably mounted on a plunger rod between spaced apart abutment portions thereon in a cylinder to permit substantially unrestrained horizontal movement between the roller and the drawbar, except for the influence of the resilient coupling when the relative horizontal movement is less than one-fourth to three-fourths of the lift of the roller, and said unrestrained horizontal movement is effected in said lost motion coupling before the restraining means becomes effective.

4. An impact roller assembly having a non-circular multi-lobed profile to obtain intermittent lift including a roller, traction rod means operatively connected at one end to bearing means for said roller and connected at the other end to resilient means which are operatively connected to a drawbar for attachment to a hauling vehicle, to provide a resilient coupling between the drawbar and the roller to Permit relative horizontal movement between the roller and the drawbar, and restraining means pivotally connected to the roller and the drawbar by fluid pressure to restrain relative horizontal movement between the roller and the drawbar exceeding one-fourth to three-fourths of the lift of the roller.

7. An impact roller assembly according to claim 4, in which the restraining means includes a lost motion coupling constituted by a plunger member slidably mounted on a plunger rod between spaced apart abutment portions thereon in a cylinder to permit substantially unrestrained horizontal movement between the roller and the drawbar, except for the influence of the resilient coupling, when the relative horizontal movement is less than one-fourth to three-fourths of the lift of the roller, and said unrestrained horizontal movement is effected in said lost motion coupling before the restraining means becomes effective.

9. An impact roller assembly having a non-circular multi-lobed profile to obtain intermittent lift including a roller, traction rod means operatively connected at one end to bearing means for said roller and connected at the other end to resilient means which are operatively connected to a drawbar for attachment to a hauling vehicle, to provide a resilient coupling between the drawbar and the roller to permit relative horizontal movement between the roller and the drawbar, and damping means operable between the roller and the drawbar to damp relative horizontal movement between the roller and the drawbar exceeding one-fourth to three-fourths of the lift of the roller, the damping means including a plunger and cylinder assembly pivotally connected between the drawbar and the roller, the plunger being arranged to partition the cylinder into two chambers and to be displaced in the cylinder by relative movement between the roller and the drawbar to displace a fluid under pressure from one chamber of the cylinder to the other via a restricted orifice to damp the movement of the plunger in the cylinder.

11. An impact roller assembly according to claim 10, in which the bell crank is so constructed that the plunger obtains a top dead center position in the cylinder when the rotatable mounting of the roller is in its mid-operating position ahead of the articulated joint.

13. Control means for controlling the movement of an impact roller having a non-circular multi-lobed profile to obtain intermittent lift which is attachable to a hauling vehicle, traction rod means operatively connected at one end to bearing means for said roller and connected at the other end to resilient means which are operatively connected to a drawbar to proviDe a resilient coupling therebetween to permit relative horizontal movement between the roller and the drawbar, the control means including frictional restraining means comprising brake means operable between the roller and the drawbar to frictionally restrain relative horizontal movement between the roller and the drawbar exceeding one-fourth to three-fourths of the lift of the roller.

14. Control means for controlling the movement of an impact roller having a non-circular multi-lobed profile to obtain intermittent lift which is attachable to a hauling vehicle, traction rod means operatively connected at one end to bearing means for said roller and connected at the other end to resilient means which are operatively connected to a drawbar to provide a resilient coupling therebetween to permit relative horizontal movement between the roller and the drawbar, the control means including brake means operable between the roller and the drawbar to brake relative horizontal movement between the roller and the drawbar exceeding one-fourth to three-fourths of the lift of the roller, the brake means including a brake member, a cam and follower arrangement and a master cylinder and a slave cylinder interconnected by a fluid line, the follower being arranged to actuate the master cylinder and the slave cylinder being arranged to actuate the brake member.

15. An impact roller assembly having a non-circular multi-lobe profile to obtain intermittent lift including a roller, traction rod means operatively connected at one end to bearing means for said roller and connected at the other end to resilient means which are operatively connected to a drawbar for attachment to a hauling vehicle, to provide a resilient coupling between the drawbar and the roller to permit relative horizontal movement between the roller and the drawbar, and frictional restraining means operable between the roller and the drawbar to frictionally restrain relative horizontal movement between the roller and the drawbar exceeding one-fourth to three-fourths of the lift of the roller, said restraining means comprising brake means for braking relative horizontal movement between the roller and the drawbar.

16. An impact roller assembly having a non-circular multi-lobed profile to obtain intermittent lift including a roller, traction rod means operatively connected at one end to bearing means for said roller and connected at the other end to resilient means which are operatively connected to a drawbar for attachment to a hauling vehicle, to provide a resilient coupling between the drawbar and the roller to permit relative horizontal movement between the roller and the drawbar, and brake means operable between the roller and the drawbar to brake relative horizontal movement between the roller and the drawbar exceeding one-fourth to three-fourths of the lift of the roller, the brake means including a brake member, a cam and follower arrangement and a master cylinder and a slave cylinder interconnected by a fluid line, the follower being arranged to actuate the master cylinder and the slave cylinder being arranged to actuate the brake member.