US3595145A

US3595145A - Soil compacting machine

Info

Publication number: US3595145A
Application number: US853173A
Authority: US
Inventors: Joachim Mozdzanowski
Original assignee: Bopparder Maschinenbau GmbH
Current assignee: Bopparder Maschinenbau GmbH
Priority date: 1968-09-11
Filing date: 1969-08-26
Publication date: 1971-07-27
Anticipated expiration: 1988-07-27
Also published as: BE738546A; NL6913091A; CA924558A; JPS4838162B1; GB1220670A; YU230669A; AT294170B; CH501777A; DE1944154A1; FR2017768A1; NO128670B; YU32204B

Abstract

A soil compacting machine has a frame carrying two soil compacting rollers mounted in tandem and at least two out of balance centrifugal force generators for vibrating the rollers as they roll the soil. At least one of the generators is mounted on the frame in front of the rollers and at least one other generator is mounted on the frame behind the rollers and both these generators are carried on shafts which extend longitudinally in the direction of travel of the machine and are relatively short compared with the width of the frame and the axial length of the rollers.

Description

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mbH., (BOMAG), am Gueterbahnhof Boppard/Rhein, Germany Primary Examiner-Nile C. Byers, Jr, Attorney-Arthur O. Klein m l Hmm i n D. .uAA w .H .m .l P lll 23|.. 333 lll [54] SOIL COMPACTING MACHINE ABSTRACT: A soil compacting machine has a frame carrying l2 Claims, 6 Drawing Figs.

two sol compacting rollers mounted in tandem and at least two out of balance centrifugal force generators for vibrating 94/50 --E01 19/ 28 the rollers as they roll the soil. At least one of the generators is 94/50, 50 mounted on the frame in front of the rollers and at least one V48 other generator is mounted on the frame behind the rollers and both these generators are carried on shafts which extend longitudinally in the direction of travel of the machine and are [5l] lnt. [50] Field of [56] Reierences Cited UNITED STATES PATENTS 4/1949 Pollitz...............

relatively short compared with the width of the frame and the axial length of the rollers.

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oachcm MozozANowsm ATTORNEY SOIL COMPACTING MACHINE can take theform of a towed roller and there may be only one generator.

The unbalancedcentrifugalforce generators are mounted on shafts and it is the usual practice to arrange these shaftsso Athat they extend'across the frame of the vehicle, that is'to say perpendicular to the direction of travel. Each generator is usually as long'asrthe-rollers ofthe machine, that isto-say the generator extends rightacross thewidth vof the machine. This makesit necessary to use long shafts for the generators, with the result that the shafts flex considerably. The diameters of the generator shafts are limited by the. amountof space availa ble. Moreover the generator shaftsare usually drivenfrom one sidefof the vehicle, and thiscauses difficulties. It is desirable to keep at least one side of the machine free from driving mechanisms, so that the machine can be driven as close as possible to edges and vertical surfaces. For thisreason existing soil compacting machines havethe drives for propelling the vehicle and for rotating the wobble generators on one side only of the vehicle. Thisv arrangement however gives the machine an awkward shape, and results in a one-sided distribution of the masses, which makesit necessary to provide balancing weights.

A vibratory compactor for yroad surfaces is known inwhich two shafts are mounted on the machine frame,abovethe rollers. These shafts extend' in the direction of travel and are driven in opposite senses. 0n the shas are mounted un-y balanced centrifugal force generators which can be shifted in position along the shafts, so as to vary the oscillation amplitude. A single `roller compactor is disclosed in U.S. Pat.No. 3,176,597 in which a vibrator is mounted over the roller and this .vibrator has `generators whose shafts extend in the direction of travel of the machine. However this machineis entirely different in kind from the machine with which the present invention is concerned because it gives. only a vertical translatory movementwhereas a double vibratory rollerl provides a rotary oscillation.

All the known unbalanced centrifugal force generators arranged in the form of double vibratory rollers have this disadvantage in common, that they have long generator shafts, which usually extend all the way across the machine and are therefore subjected to considerable bending stresses. The lresulting flexion of the shafts applies undesired stresses to the drive. It is difficult to prevent the flexion without wasting considerable space, and the attempts to prevent the flexion of the shafts sometimes fail due to the lack of available space. Furthermore if the generator shafts are of large diameter, the

bearings also have to be correspondingly large. This is not onlyA costly but also involves a high rate of production of heat, because of course a large bearing produces heat more rapidly than a small one.

Thel object of the ypresent invention is to `arrange the unbalanced centrifugal force generators of a soil compacting machine in such a way that thecost of construction is reduced and in such a way that it becomes possible to position the generators at the bestlocations in the machine for producing the desired rotary oscillation, that is to say` for giving the machine the desired rocking movement. l

To this end according to this invention, the generators in a l soil compacting machine comprising at least two rollers arranged in tandem and mounted in a frame, and at last one out of balance centrifugal force generator is mounted `in the frame.- lf therel areA two out .of balance centrifugal forced generators provided, one is mounted in front of and one behind the rollers on short shafts extending in the directionof travel of the machine.

The-shafts of the generators are much shorter than the rollers or much shorter than the width of the frame of the machine. The generators may be mounted in housings in the form of transverse members which rigidly tie together longitudinal side members of the frame. Each transverse beam may contain several generators, the drives of which need not be located in or on side members of the frame.

Using very short generator shafts provides the important advantage that they can have comparatively small diameters, and the bearings can be comparatively small. ln a preferred example of the invention the shafts of the generators are located at substantially the same'height as axles onvwhich the rollers are mounted. With this arrangement particular advantages can be obtained by mounting in each end of the machine, two, four, or even more generators rotating in opposite directions, to the effect that a directional oscillation is obtained. This has the advantage that the system of generators produces no forces which stress the frame of the machine in tension. The same advantage may of course be obtained by mounting one generator at each end of the machine, but this would result in oscillations about the middle vertical axis of the. vehicle. Generators rotating in opposite directions are therefore preferred.

Arranging the shafts of the generators so that they extend longitudinally in the machine, that is to say in the direction of travel,.allows the drives to be accommodated between vertical planes containing the longitudinal side members of the frame, and above the rollers. With this arrangement it is not necessa- Vry to position the propulsion drive for the machine, and the drive for the generators at one side of the machine. The

machine is therefore comparatively narrow, and the soil can i be compacted close up to vertical surfaces. The generators may be driven and if necessary synchronized by means of gear wheels. Each generator may for example take the form of a toothed disc the teeth of Awhich engage with those of a neighboring disc.

ln a preferred example of the invention, the drive for the generators is by means of a toothed belt which has teeth on both sides. The belt extends around a driving disc, around four toothed generator discs and around an idler roller, in such a way that pairs of generator discs rotate in opposite directions. The same principle can be applied to more than four generator discs. lf desired the generators can be driven through Carden shafts.

The engine, which drives the generators and also serves for propulsion of the machine is preferably spring mounted on the frame of the machine substantially centrally. The drive may be mechanical, or if desired hydraulic.

An example together with some modifications of a soil compacting machine constructed in accordance with the invention is illustrated somewhat diagrammatically in the accompanying drawings in which:

FIG. l is a side view of the machine;

FlG. 2 is a plan view;

FIGS. 3 to 6 are end views of the machine and of the machine modified by the substitution of different centrifugal force generators.

The machine has four rollers l, 3 and 2, 4, rotatably mounted on

axles

5 and 6, the ends of which are fixed in

side members

7, 8 of a frame of the machine. Gear wheels 25 for driving the rollers l, 2, 3, 4 are mounted on axles which rotate in bearings in the

members

7, 8. A source of power, in this example a Diesel engine 13 is spring mounted above the rollers on a supporting frame 1S, there being disposed coiled springs 14, or other springing devices, between the supporting frame 15 and the frame of the machine. The driving engine 13 drives a hydraulic pump 16 on a flange of which a controller 17 is mounted. The driving engine 13, the hydraulic pump land the controller 17 form a single structural unit.

For the propulsion drive, the engine 13 drives

hydraulic pumps

50 and 51, the hydraulic fluid passing through pipes 54 and S to drive

hydraulic motors

52 and 53.

From the hydraulic pump 16, pipes 18 convey hydraulic fluid to

hydraulic motors

19 and 20, one at each end of the frame. The two

hydraulic motors

19 and 20 dn've

gear wheels

29, 30 which rotate in bearings in two transverse frame members 9 and l0, at the front and rear ends of the machine. The two

transverse members

9 and 10 form housings which contain, as shown for example in FlG. 3, unbalanced

centrifugal force generators

31, 33, 35, 37 and 32, 34, 36, 38 in the form of unbalanced discs on short shafts 1l, 12 extending longitudinally in the machine, that is to say in the direction of travel. Each disc has peripheral teeth engaging with those of a neighboring disc. The drive from the

gear wheels

29 and 30 mounted on the shafis of the

hydraulic motors

19, 20 is transmitted from

toothed wheels

39, 40 to the

generator discs

33, 34 by toothed belts 56. lf desired, instead of what is shown in the drawings, the machine can be equipped with a single generator disc, to give a circular oscillation. Preferably however the generator discs are arranged in oppositely rotating pairs to give a directional oscillation.

For synchronizing the generators at the front and rear ends of the machine there are connecting

shafts

22, 23 with flexible joints, connected together by a middle shaft 24.

In the modifications shown in FIGS. 4 to 6, the generators are driven and synchronized by a toothed belt 4l, which has teeth on both sides. ln this case the generators 42 to 45 do not engage directly with each other. Each generator disc has peripheral teeth which engage with the teeth of the belt 41. The belt 4l is trained around the discs in such a way that the

discs

42 and 43, and the discs 44 and 45 (not shown) are driven as oppositcly rotating pairs, ln FIG. 4 for example, the belt is taken anticlockwise around the disc 42, and clockwise around the disc 43. When the two unbalanced weights, in dicated by broken lines in the drawing, rotate in opposite directions, they simultaneously reach their extreme upper, lower, inner and outer positions, producing a directional oscillation.

Similarly the toothed belt 4l is taken clockwise around the disc 44 and anticlockwise around the disc 45. The drawing shows a toothed wheel on the shaft of the hydraulic motor at 30a, and an idler roller at 46.

If the machine in accordance with the invention is in the form of a double vibration roller, that is to say a doubleroller rocking-action compactor, arranging the generators in the manner in accordance with the present invention has the particularly advantage that the longitudinal chasses members do not have to take the longitudinal stresses applied by generators which are positioned at the two ends of the machine and are 180 out of phase, in passing through their extreme outer and extreme inner angular positions. A special advantage obtained by mounting the generators with their axes extending fore-and-aft, is that the generator axles can be mounted to rotate in bearings in the cross members of the vehicle, or in housings arranged transversely in the vehicle, so that the system of generators can easily be removed from the vehicle for maintenance purposes. This advantage is obtained irrespective of whether the generator discs drive each other directly by their teeth, or are driven individually by a toothed belt.

Mounting the generator discs on short shafts extending longitudinally in the vehicle also provides the particular advantage that the generators can if desired rotate at different speeds, or rotate without synchronization. For example the forward generator can give an oscillation frequency of 30 Hz., the rear gehemmt giving an oscillation at 47 Hz. A vertical rocking motion results with a frequency of l7 Hz. which is approximately the resonant frequency of the soil. By varying the frequencies the vertical rocking movement can be made to agree with the resonant frequency of the particular soil, giving a particularly favorable compacting effect. ln this way the machine can be adjusted for each particular type of soil.

The particular advantages of the machine in accordance with the invention are, in the first place, that any desired pairs of generators can be selectively installed at the front and rear ends of the machine. The generators can be driven to rotate at any desired speeds, for example by using gear wheels of different diameters, to suit different operating conditions. Locat ing the power source in the middle of the vehicle minimizes the width of the vehicle. Locating the generators near the ends of the machine provides the greatest possible vibratory rocking torque.

Although the invention is illustrated and described with reference to a plurality of preferred embodiments thereof, it is to be expressly understood that it is in no way limited to the disclosure of such a plurality of preferred embodiments, but is capable of numerous modifications within the scope of the appended claims.

lclaim:

1. ln a soil compacting machine including a frame, at least two soil compacting rollers, means mounting said rollers in tandem in said frame, at least two out of balance centrifugal force generators and means mounting said generators in said frame, the improvement wherein said generator mounting means includes first means mounting at least one of said generators in front of said rollers and second means mounting at least one other of said generators behind said rollers both said first means and said second means including a relatively short shaft extending in the direction of travel of said machine.

2. A machine as claimed in claim l, wherein said means mounting said rollers in said frame includes horizontal axle means and further comprising bearing means mounting said shafts of said first and said second means at substantially the same height as said axle means.

3. A machine as claimed in claim l, wherein said frame includes longitudinal side members and transverse members interconnecting said longitudinal side members in front of and behind said rollers, said transverse members including portions defining housings and said generator mounting means mounting said generators in said housings.

4. A machine as claimed in claim l, wherein said frame includes longitudinal side members disposed one at each end of said rollers and further comprising engine means and drive means operatively connecting said generators to said engine, said drive means being located above said rollers and between vertical planes containing said longitudinal side members.

5. A machine as claimed in claim l, wherein each of said generators includes a pair of unbalanced discs, means rotatably mounting said discs and means for rotating said discs in opposite directions to each other.

6. A machine as claimed in claim 5, further comprising peripheral teeth on said discs, said teeth of said discs in each of said pairs of discs meshing with each other.

7. A machine as claimed in claim S, further comprising peripheral teeth on said discs and toothed belt means meshing with said teeth on said discs of each of said pairs.

8. A machine as claimed in claim 7, further comprising teeth on both sides of said belt, an idler roller, and means extending said belt around said idler roller, around one of said discs in said pair in a clockwise direction and around the other of said discs in said pair in an anticlockwise direction.

9. A machine as claimed in claim 1, further comprising means for driving said generators, means mounting said driving means on said frame and universally jointed shaft means operatively connecting said driving means to said generators.

10. A machine as claimed in claim including engine means for driving said generators, means mounting said engine means on said frame, ahydraulic pump, means operatively coupling said pump to said engine means, at least two hydraulic motors, means operatively connecting said pump to said motors and means operatively connecting each of said motors to one of said generators.

11. A machine as claimed in claim l, further comprising means for operating said generator in front of said rollers to produce a first oscillation frequency and means for driving tion frequency different from said first oscillation frequency.

l2. A machine as claimed in claim l. comprising at least two pairs of said generators, and means detachabl y mounting each of said pairs of generators on said frame.

Claims

1. In a soil compacting machine including a frame, at least two soil compacting rollers, means mounting said rollers in tandem in said frame, at least two out of balance centrifugal force generators and means mounting said generators in said frame, the improvement wherein said generator mounting means includes first means mounting at least one of said generators in front of said rollers and second means mounting at least one other of said generators behind said rollers both said first means and said second means including a relatively short shaft extending in the direction of travel of said machine.

2. A machine as claimed in claim 1, wherein said means mounting said rollers in said frame includes horizontal axle means and further comprising bearing means mounting said shafts of said first and said second means at substantially the same height as said axle means.

3. A machine as claimed in claim 1, wherein said frame includes longitudinal side members and transverse members interconnecting said longitudinal side members in front of and behind said rollers, said transverse members including portions defining housings and said generator mounting means mounting said generators in said housings.

4. A machine as claimed in claim 1, wherein said frame includes longitudinal side members disposed one at each end of said rollers and further comprising engine means and drive means operatively connecting said generators to said engine, said drive means being located above said rollers and between vertical planes containing said longitudinal side members.

5. A machine as claimed in claim 1, wherein each of said generators includes a pair of unbalanced discs, means rotatably mounting said discs and means for rotating said discs in opposite directions to each other.

7. A machine as claimed in claim 5, further comprising peripheral teeth on said discs and toothed belt means meshing with said teeth on said discs of each of said pairs.

10. A machine as claimed in claim 1, including engine means for driving said generators, means mounting said engine means on said frame, a hydraulic pump, means operatively coupling said pump to said engine means, at least two hydraulic motors, means operatively connecting said pump to said motors and means operatively connecting each of said motors to one of said generators.

11. A machine as claimed in claim 1, further comprising means for operating said generator in front of said rollers to produce a first oscillation frequency and means for driving said generator behind said rollers to produce a second oscillation frequency different from said first oscillation frequency.

12. A machine as claimed in claim 1, comprising at least two pairs of said generators, and means detachably mounting each of said pairs of generators on said frame.