GB2226616A

GB2226616A - Improved vibratory mechanism for a compaction roller

Info

Publication number: GB2226616A
Application number: GB8913666A
Authority: GB
Inventors: Thomas Gerald Artzberger
Original assignee: MBW Inc
Current assignee: MBW Inc
Priority date: 1988-06-24
Filing date: 1989-06-14
Publication date: 1990-07-04
Also published as: GB8913666D0; JPH032403A; DE3920316A1; FR2633203A1

Description

11 c IMPROVED VIBRATORY MECHANISM FOR A COMPACTION ROLLER The typical

self-propelled compaction roller includes a main frame or chassis that supports an engine which serves to operate drive wheels to propel the roller over the terrain. A drum frame is pivotally connected by a universal joint to the main fraine and rotatably supports a compaction drum or roller. A vibratory mechanism is mounted on the drum frame and acts to vibrate the drum to aid in compaction.

A common type of vibratory mechanism includes a hydraulic motor and a weight is mounted eccentrically with respect to the output shaft of the motor. The eccentric weight generates vibratory forces throughout the 3600 rotation of the shaft. While the vertical vibratory forces aid in compaction, the fore and aft vibratory forces are transmitted through the machine and can cause severe wear and maintenance problems. 1n an attempt to isolate the vibrations from the main frame of the machine, shock mounts are utilized to connect the drum frame to the main frame, as well as mounting the engine on the main frame.

As a further problem, when forces are generated throughout the 3600 rotation of the shaft, harmonic vibrations may be set up, which act to cancel out the vertical vibratory forces, so that the compaction forces are not maximized.

It is also known to employ a separate vibratory unit or exciter for each drum in a double drum compaction roller. in a unit of this type an eccentric weight is mounted on each output shaft and the weights are arranged so that when a downward vertical vibratory force is generated by one eccentric weight, an upward vertical vibratory force is generated by the otner 1 weiaht. The result is that the compaction forces are aenerated in sequence, and the sequenced vibrations are desirable in certain applications, as in asphalt pavinq operations, to eliminate skip narks.

The invention is directed to an improved vibratory mechanism for a compaction roller. A compaction drum, is journalled on a drum frame which is connected to the main frame of the roller by an articulated joint. The vibratory mechanism includes a housina which is mounted on the drum frame and a pair of parallel shafts are journalled within the housinq. A separate power unit, such as a hydraulic motor, is oPerablv connected to one of the shafts to drive the same, while a qear train connects that shaft with the second shaft, so that the shafts operate in onnosite directions and at the same speed.

An eccentric weight is connected to each shaft and the weights are preferably formed of identical shane and size. The weiqhts are arranced on the shafts so that the vertical vibratory forces qenerated by the weights during rotation of the shafts are added, while the fore and aft vibratory forces generated by the weights are cancelled. To provide this arranaement, the center mass of one weiqht is disposed above and in a vertical plan extendina throijoh the axis of the respective shaft when the center of the mass of the other weiqht is disposed above and in a vertical plane extending throuoh the axis of its correspondinq shaft.

With the construction of the invention, the horizontal or fore and aft vibrations are substantially eliminated, thereby minimizing the transmission of vibrations to the main frame of the shaft. As the transmission of unwanted vibrations to the main frane is minimized, wear and maintenance of the machine is substantially reduced.

1 As a further advantage, the shock mounts which interconnect the drum frame to the main frame, can be reduced in complexity, due to the fact that the shock mounts need only resist vertical vibratory motion as opposed to resisting universal vibratory motion as in a conventional compactor roller.

Further, the drum shaft, which journals the compaction drum, as well as the universal joint, that connects the drum frame to the main frame, are only subjected to vertical stress and this substantially reduces the wear on the shaft bearings as well as on the universal joint.

other objects and advantages will appear in the course of the following description.

The drawings illustrate the best itiode presently contemplated of carrying out the invention.

In the drawings:

Fig. 1 is a perspective view of a compaction roller incorporating the vibratory mechanism of the invention; Fig. 3 is a front elevationsl view of the vibratory mechanism, with parts broken away in section; eig. 3 is a section taken along line 3-3 of Fig. 2.

I Fig. 1 illustrates a compaction roller incorporating the vibratory or exciter mechanism of the invention. The compaction roller itself can be (onstructed in the manner described in the United States Patent No. 4,732, 507 and consists of a main frame 1 which supports an engine 2 and the engine is operably connected to the drive wheels 3 which are journalledon the frame 1. operation of the engine 2 will propel the roller over the terrain.

A druri frame 4 is connected to the forward end of main frame 1 by a universal joint connection, not shown, and a drum 5 is journalled on shaft 6 that is carried by druri frame 4.

The vibratory mechanism 7 of the invention is mounted on horizontal plate 8 of drum frame 4 and includes a housina 9 composed of a central section 10 and a pair of end sections 11 and 12 which are connected to the central section by bolts 13. Housinq 9 is connected to plate 8 of drum frame 5 by a series of mountinq bolts 14 which extend through openinns in the central section 10 and end section 12 resnectivelv.

A hydraulic motor 15 is nounted on end section 11 and the drive shaft 16 of motor 15 is connected via a couplina 1-/ to a shaft 18.

Shaft 18 is journalled within bearinas 19 that are carried by the central section 10 and end section 12, respectively, of housinq 9. As shown in Fia. 3, shaft 18 carries a qear 2U which meshes with a pear 21 of identical diameter that is mounted on shaft 22. Shaft 22 is parallel to shaft 18 and is journalled within bearinqs 23 that are mouonted in the housinn sections 10 and 12, resnectively.

Shafts 18 and 22 carry eccentric weinhts 24 and 25 resnectively which extend radially from the axis of the resnective shaft. As illustrated in Fiq. 2, each weiaht 24,25 extends throuah an arc of 90' to 180' and preferably about 1601. The center of mass of each weiqht is spaced radially from the respective shaft and the center of mass of weiqht 24 is disposed abov and in a vertical plane extending throuqh the axis of shaft 18 when the center of mass of weiaht 25 is disposed above and in a vertical plane extendinq throuqh the axis of shaft 22. With this construction, as the shafts 18 and 22 rotate in opposite directions, the the vertical vibratory forces generated by eccentric weights 24 and 25 add together to aid in compaction, while the horizontal or fore and aft vibratory forces generated by the weights will cancel to minimize transmission of unwanted vibrations to the main frame, thereby reducing wear of the machine and simplifying the shock mount construction as it is only necessary to dampen the vertical vibrations.

Various modes of carrying out the invention are contemplated as being within the scope of the following claims particularly pointing out and distinctly claiming the subject matter which is regarded as the invention.

Claims

1. A vibratory unit for a compaction apparatus, comprising a frame including a compaction drum, power operated means mounted on the frame, a first shaft operably connected to said power operating means, a second shaft disposed parallel to said first shaft, interconnecting means for interconnecting the shafts and driving the shafts at the same speed and in opposite directions, a first weight secured to said first shaft in an eccentric relation, and a second weight secured shaft in an eccentric relation, said weights being identical in size and shape and said weights being connected to the respective shafts in a manner whereby the vertical vibratory forces generated by the weights during rotation of the shafts are added and the horizontal vibratory forces generated by the weights during rotation of said shafts are cancelled.

2. A vibratory unit for a compaction roller, comprising a frame, power operated means mounted on the frame, a pair of shafts, a first of said shafts being operably connected to said power operated means, interconnection means for interconnecting said shafts and driving said second shaft at the same speed and in opposite directions from said first shaft, weight secured to each shaft in an eccentric relation to the respective shaft, the centre of mass of each weight being spaced radially from the respective shaft, the centre of mass of a first weight being disposed above and in a vertical plane extending through the axis of the first shaft when the centre of mass of the second weight is disposed above and in a vertical plane extending through the axis of said second shaft.

1 4

3. A vibratory unit according to claim 1 or claim 2, 0 wherein each weight extends through an arc of 90 to 0

4. A vibratory unit according to claim 1 or claim 2, wherein said interconnecting means comprises gear means.

5. A vibratory unit according to claim 1 or claim 2, and including a housing mounted on said frame, and means connected to said housing for journalling said shafts for rotation, said interconnecting means being disposes within said housing.

6. A vibratory unit according to claim 1 or claim 2, wherein said power operated means comprises a hydraulic motor.

7. A vibratory unit substantially as hereinbefore described with reference to the accompanying drawings.

Published 1990 at The Patent Office. State House-66 71High-;7-". Further copies may be obtamed from The Palent 0,'Aicc