Land vehicles: bodies and tops – Bodies – Structural detail
Reexamination Certificate
2001-10-25
2004-03-23
Dayoan, D. Glenn (Department: 3612)
Land vehicles: bodies and tops
Bodies
Structural detail
C180S089120, C180S089130
Reexamination Certificate
active
06709046
ABSTRACT:
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an improvement in a supporting structure of an operator cab for a work machine, such as a bulldozer, wherein a supporting structure for an operator cab is mounted on a floor frame which has a front portion and rear portion different in height.
BACKGROUND OF THE INVENTION
Work machines, particularly bulldozers, are mainly used in earth work on irregular ground. The body of a work machine is subject to a large vibration during vehicle travel. A supporting structure is generally mounted between a body frame of a work machine and its operator cab to prevent the vibration from transiting to the latter through the former, which results in providing the operator with a great comfort in the cab and a stable operator posture during operation.
U.S. Pat. No. 5,498,060 issued on Jun. 18, 1999, assigned to the assignee of the present invention, discloses a floor frame supporting structure of a work machine such as bulldozers. As shown in
FIG. 19
, a cab
41
is mounted on a floor frame
42
having substantially Z-shaped configuration including a front portion and a rear portion which is high than the front portion. A front right side portion and a front left side portion of the floor frame
42
, as shown in
FIG. 20
, are respectively coupled to the body frame
43
through buffer support means
44
,
44
, which are supported ally in a direction of pitching movement through rubber bushings
44
A,
44
A on periphery of shafts
44
B,
44
B mounted pivotally to the floor frame
42
. The rear right side portion and the rear left side portion of the floor frame are respectively supported by the supporting structures, which absorb vibration in the vertical and transversal directions, to a pair of brackets
46
,
46
fixed to the body frame
42
. The supporting structure as shown in
FIG. 21
comprises a multi-layer rubber mount viscous damper
45
including a tubular resilient cushion member
47
such as rubber or plastics, a damper plate
49
and non-compressive damper oil
48
in a chamber, and are respectively secured to the front left side portion and the rear left side portion of the floor frame
42
so as to absorb transversal and vertical shock loads from the body frame
42
.
Another Japanese utility model application application No. 1989-99776 applied on Oct. 27, 1988 assigned to Kubota Tekko in
FIG. 22
, discloses that at least one of front side portions and rear side portions of a floor frame are respectively coupled to a body frame through rubber or plastics front or rear buffer support means
53
F,
53
R in
FIG. 23
including rubber mount members
56
,
56
having a truncated cone configuration in FIG.
24
. Each axis of the supporting structures are respectively oriented at an angle within the range from the their central axis so as to orient toward the center of gravity of a operator cab in the transversal direction and longitudinal direction of a work machine.
There are drawbacks associated with these convention technology described above.
U.S. Pat. No. 5,498,060 discloses that since the rubber bushings
44
A,
44
B of the buffer support means
44
, are needed to have a sufficient rigidity to absorb vibration generated in vertical direction at the low floor portion. The rubber bushing
44
A,
44
B can provide an insufficient damper effect to absorb a vertical heavy shock load, such as is caused when the work machine runs over an obstruction. With such a problem, vertical vibration of the operator cab is converted to pitching movement with respect to a shaft of the buffer support means
44
. This pitching movement is absorbed by the buffer support means
45
R secured to a high both side portions of the floor frame. However, since the high both side portions of the floor frame
42
are subject to pitching movement with respect to the shaft of the buffer support means
44
e.g. the rubber mount viscous dampers
45
can receive not only the shock load in the vertical direction, but also the that in the longitudinal direction of a work machine. In order to prevent from a transversal motion or rolling motion of the operator cab, a transversal spring constant of the rubber mount or the tubular rubber cushions
47
in the perpendicular direction to the support axis thereof is set to hard. Similarly, the rigidity of the tubular rubber cushions
47
in the longitudinal direction of a work machine is stronger than that in the vertical direction, e.g. the transversal movement thereof is restricted.
Therefore, the rubber mount viscous damper involves a problem in that a vertical shock load, such as is caused when the work vehicle runs over an obstruction, cannot be sufficiently absorbed by pitching movement centering around the axis of a shaft
44
B.
The buffer support means
53
F,
53
R disclosed in U.S. Pat. No. 5,498,060 are respectively located at positions which are approximately as high as the height of each other and the support axis thereof is inclined at a angle &thgr; to the vertical axis toward the center of gravity in the longitudinal and transversal directions so as to prevent from transversal movement of the operator cab. However, in the case that the buffer support means
53
F,
53
R are positioned apart from a operator cab, this invention involves problems in that the operator cab has a large displacement during longitudinal and transversal motion.
The present invention is directed to overcoming one or more of the problems described above.
Therefore it is an object of the present invention to provide such a supporting structure of an operator cab of a work machine so as to have a great absorption for accommodating a vertical movement and pitching movement from the body frame of work machine to the operator cab.
DISCLOSURE OF THE INVENTION
In a supporting structure for an operator cab on a body frame of a work machine, having a floor frame, the operator cab being mounted on the floor frame which has a low floor portion and a high floor portion spaced longitudinally from each other at a forward location and a rearward location in a side view, and a plurality of vibro-isolating support means being provided between said low and high floor portions and said body frame so as to support the operator cab resiliently, at least one of said vibro-isolating support means located at the low floor portion and the high floor portion having a support axis which inclines longitudinally at a predetermined angle (&thgr;) from vertical axis toward the center of gravity (G).
Since lateral and longitudinal rigidity of the supporting structure can be varied depending on a inclination angle from a vertical axis at which they are secured to a bracket fixed to the body frame, setting a suitable inclination angle of the supporting structures can bring an optimum responsibility or damping effect for vertical movement, pitching movement, transversal movement and rolling movement from the body frame to the operator cab.
In a supporting structure for an operator cab on a body frame of a work machine having a floor frame including a low floor portion and a high floor portion spaced longitudinally from each other in the longitudinal direction of a work machine, a vibration mode in that the operator cab moves pitching movement centering around adjacent the support point of the supporting structures mounted vertically on either the front floor portion or the rear floor portion of the floor frame, provides an great important effect to absorb vibrations.
In the vibration mode, by inclining at a suitable angle the supporting structures mounted at least one of the front floor portion and the rear floor portion of the operator cab, the inclined support axis of the supporting structure, which a small rigidity or spring constant of the supporting structure is usually set to small along, is substantially coincident with the direction of vibration (line of action of a shock load) on pitching movement centering around a support point adjacent the other supporting structures.
This causes a restrain against the displacement of the supporting structure to r
Kamado Mitsuhiko
Kanayama Noboru
Mitsuta Shinji
Okazawa Kouji
Coletta Lori L
Dayoan D. Glenn
Komatsu Ltd.
Varndell & Varndell PLLC
LandOfFree
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