Vibratory roller

Details Vibratory roller Vibratory roller

2001-06-01

2002-06-11

Pezzuto, Robert E. (Department: 3673)

Road structure, process, or apparatus

Apparatus

Means to agitate material

C404S122000, C404S132000

Reexamination Certificate

active

06402424

ABSTRACT:

FIELD OF THE INVENTION
The present invention relates to a vibratory roller for compacting a road surface and the like.
BACKGROUND OF THE INVENTION
Compacting rollers are used for compacting an embankment of a road or a dam structure, or for compacting a road surface with asphalt paving. Generally, compacting rollers with steel wheels are classified, in terms of arrangement of the compacting wheels (hereinafter referred to as “rolls” ), into a tandem type, in which front and rear rolls are arranged in line so that one rut is positioned on top of the other between the ruts of the front and rear rolls, and a macadam type, in which three rolls are employed. Further, a-vibration generating device may be provided on the compacting roller. The compacting roller with a vibration generating device enables to compact the road surface at high densities because it can compact the road surface while vibrating the rolls. The vibration generating device is applicable to both tandem type and macadam type rollers, and the compacting roller with the vibration generating device is known as a vibratory roller.
Of these compacting rollers, a macadam-type vibratory roller is disclosed in Japanese Utility Model Publication No. HEI.3-24647.
FIG. 9
schematically shows an inner structure of the roll of the conventional macadam-type vibratory roller. As shown in
FIG. 9
, a stationary portion
53
a
of a roll-driving motor
53
, which rotates a roll
52
, is fixed to a side of a body
51
, and an output portion
53
b
of the roll-driving motor
53
is fixed to the roll
52
through a bracket
54
and rubber vibration isolators
55
. A reference numeral
56
indicates a vibration generating device. A casing of the vibration generating device
56
is fixed to the roll
52
, and the vibration generating shaft (not shown) within the casing is connected to a vibrating motor
57
. A stationary portion
57
a
of the vibrating motor
57
is fixed to a bracket
58
, which extends from an upper part of the body
51
toward the outer surface of the roll
52
and further into the inner region of the roll
52
.
In most cases, the macadam-type vibratory roller and the tandem-type vibratory roller are distinct in its usage. The tandem-type vibratory roller is used when widely and entirely compacting a road surface, such as an asphalt pavement, and the macadam-type vibratory roller is used when compacting and connecting a joint between newly constructed road surfaces or a joint between a newly constructed road surface and an existing road surface.
In a compaction work with the use of the tandem-type vibratory roller, the following drawbacks have been pointed out.
(1) Problem Relating with Compacting Width
Normally, the tandem-type vibratory roller in 7 to 9 tons has a compacting width (or roll width) of about 1.5 to 1.7 meters. For example, when compacting one traffic lane of a roadway (viz. about 3.8 meter width), at least three compacting lanes are required. In order to reduce the number of compacting lanes, it is considered that the roll width may be increased. However, increasing the roll width would result in increased dragging of the road surface at the end of the roll positioned at the outer side of a curve, for example when compacting the curved road surface while turning the vibratory roller. This leads to deterioration in pavement quality. Such a problem can be overcome by dividing the roll into plural parts and providing a differential mechanism or differential gears. However, this is not preferable because the construction of the vibratory roller becomes complicated and the manufacturing cost thereof also increases.
(2) Problem Relating with Contacting Characteristics
In terms of drain, the roadway is usually paved to create a slight inclination from the centerline to both road ends, as illustrated in FIG.
8
. When compacting such a roadway by the tandem-type vibratory roller along the centerline, the contacting characteristics of the roll
61
becomes worse at its ends due to the width of the roll
61
. This is shown in FIG.
8
A. As a result, there would be an irregularity in compaction between the road surface compacted by the center part of the roll
61
and the road surface compacted by the end parts of the roll
61
.
(3) Problem Relating with Roll Diameter
Generally, as the roll diameter becomes greater, the contacting characteristics against the road surface may be improved and smoother finishing of the road surface can be achieved. However, in the tandem-type vibratory roller, increasing the diameter of the roll would arise other drawbacks, such as deteriorated visibility from the driver's seat and increased size of the body.
(4) Problem Relating with Side Overhang
In the tandem-type vibratory roller, a supporting member, such as a yoke, is positioned outwardly of the end surface of the roll. For this reason, when compacting the road surface in close proximity to a wall of the structure, the operator cannot move the roll in the immediate proximity position toward the wall because of a projection amount of the supporting member (side overhang), and so non-compacting parts remain on the road surface. In this event, a further operation is required to compact the non-compacting parts, and compacting equipment such as a tamper is conventionally used for this purpose.
In order to eliminate the above drawbacks, if the macadam-type vibratory roller is used, instead of the tandem-type vibratory roller, for entirely compacting the road surface, it may be advantageous in the following reasons.
With regard to the problem (1) relating with compacting width, the macadam-type vibratory roller has a constitution such that either front or rear rolls are positioned in pair at both sides of the body, and a differential mechanism is already provided or a differential mechanism is readily mounted. Therefore, dragging of the road surface hardly occurs during the compaction on the curved road surface, even if the compacting width (viz. the total width of the three rolls except for the superposed roll width) is increased. The compacting width of the 9 to 12 ton class macadam-type vibratory roller is generally about 2.1 meters, and when compacting the aforementioned lane (about 3.8 meter width) of the roadway, only two compacting lanes are required.
With regard to the problem (2) relating with contacting characteristics, it is preferable when compacting the road surface with a slight inclination by the macadam-type vibratory roller as illustrated in
FIG. 8B
than when compacting by the tandem-type vibratory roller as illustrated in
FIG. 8A
, because the width of each roll
52
is smaller, which leads to excellent contacting characteristics against the road surface. The finishing quality of the road surface is therefore uniform, and in other words, there are few differences in the road surface qualities due to compaction at different parts of the roll.
Further, with regard to the problem (3) relating with roll diameter, the macadam-type vibratory roller does not suffer from deteriorated visibility from the driver's seat or increased size of the body, because a pair of rolls
52
is supported at both sides of the body
51
and thus increasing the roll diameter does not affect the body
51
positioned intermediate between the rolls
52
.
As mentioned above, various remarkable effects can be expected when compacting the road surface with the use of the macadam-type vibratory roller. However, when compacting the road surface widely and effectively, the whole rolls including the pair of right and left rolls
52
have to be vibrated simultaneously. In the conventional macadam-type vibratory roller, it is difficult to vibrate the right and left rolls
52
simultaneously by the following reasons.
As shown in
FIG. 9
, the macadam-type vibratory roller comprises a pair of rolls
52
axially supported at both sides of the body
51
. Since the width of each roll
52
is considerably small in comparison with that of the roll of the tandem-type vibratory roller, on one hand, it is effective for the aforementioned problems

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