1. Field of the Invention
The invention relates to a monolever operating device, and more particularly, to a monolever operating device, which is excellent in abrasion resistance, good in durability and high in reliability and can be conformed to many kinds of machines.
2. Description of the Related Art
Inventions have been already known relating to an operating lever device, in which a single operating lever (referred below to as a xe2x80x9cmonoleverxe2x80x9d) is operatively inclined to generate an operating signal and two hydraulic actuators are drivingly controlled on the basis of the operating signal. For example, Japanese Patent Laid-Open No. 89515/1997 discloses an electrical type operating lever device, in which a monolever is operatively inclined to have each of four pistons issuing an electric signal representative of its displacement. Two hydraulic actuators can be drivingly controlled on the basis of an electric signal issued from the electrical type operating lever device.
Also, Japanese Utility Model Publication No. 49167/1995 discloses a hydraulic type operating lever device 60 which outputs a hydraulic signal. In this publication, the hydraulic type operating lever device 60 comprises a hydraulic body 63 having four pistons 62, which are pressed upon inclination of a monolever 61 in a front and rear direction and in a right and left direction, and of which respective displacements are output as hydraulic signals, on the basis of which two hydraulic actuators can be drivingly controlled.
With the hydraulic body 63, four pistons 62a, 62b, 62c, 62d (shown in FIG. 2), which constitute a piston 62, are arranged in equidistant positions on a circumference in a manner to abut against a disk plate 64 mounted on the monolever 61. The four pistons 62a, 62b, 62c, 62d are pushed and displaced by the disk plate 64 in accordance with an orientation and an amount of inclination of the monolever 61.
Hydraulic pressure generating means Hd for generating a hydraulic signal of a magnitude corresponding to respective displacements of the pistons 62a, 62b, 62c, 62d are provided on the hydraulic body 63. In addition, the hydraulic body 63 comprises a drive signal generating body and the hydraulic pressure generating means Hd comprise a drive signal generating means.
The monolever 61 is mounted to the hydraulic body 63 through a universal joint 65. The hydraulic body 63 is mounted on a mount plate 66 shown in FIGS. 7(a) and 7(b) and on a vehicle body 68 near a driver seat by means of bolts 67 extending through vehicle body bolt holes 66a formed in the mount plate 66.
In FIGS. 7(a) and 7(b), the mount plate 66 is provided with a ring-shaped stopper projection 69, which in turn is provided with arcuate-shaped projections 69a adapted to abut against the disk plate 64 to restrict an inclination xcex8 of the monolever 61. The mount plate 66 is provided with an annular groove 69b on an outer periphery of the ring-shaped stopper projection 69. One end of a boot 70 covering the four pistons 62 is inserted into the annular groove 69b. Also, the other end of the boot 70 is inserted into an annular groove 71a provided on an outer periphery of a coupling 71, which connects the universal joint 65 and the monolever 61 to each other as shown in FIG. 6.
In recent years, the operating lever device constituted in the above manner has been improved in operability and made small in size to be used in many construction machines and industrial machinery such as small-sized and large-sized hydraulic shovels, bulldozers, rough terrain cranes and so on.
With the above constitution, Japanese Utility Model Publication No. 49167/1995 proposes the provision of a single mount plate for parts to improve an increase in cost, caused by an increased number of parts due to the fact that a part for mounting of a boot is separate from a mount plate.
However, since the operating lever device has been used in many construction machines and industrial machinery in recent years as described above, the mount plate shown in FIGS. 7(a) and 7(b) differ in configuration and dimension of inclination every machine, and so manufacture of the single mount plate necessitates a new metallic mold to lead to an increase in cost of parts and a large amount of expense in manufacture of a metallic mold.
For example, the mount plate is fabricated from a sintered material to shape the projection for stoppage and the arcuate projection in order to facilitate manufacture and realize cost reduction. There is caused a problem that a metallic mold for manufacture of the sintered material is increased in manufacture cost since an annular groove is provided on a side of the mount plate and manhour in assembling is increased at the time of manufacture.
Also, since the mount plate is fabricated from a sintered material, the projection for stoppage and adapted to abut against the disk plate is worn. Such wear causes a problem that the operating lever device becomes hard to operate because an operating lever is increased in stroke after use over a long term.
When the projection for stoppage is further increased in thickness in order to prevent the wear, there is caused a problem that the operating lever device becomes large and so difficult in use for small-sized construction machines or a major part of the device must be made large to impose a limitation on a driver seat. Also, a part for mounting of a boot and a mount plate are conventionally separate from each other, and so there is caused a problem that the boot is worsened in assembling property and cost is increased since the part does not function as a bearing portion for inclination of the operating lever and so other part is needed.
The invention has been thought of in view of the above problems, relates to a monolever operating device and has its object to provide a monolever operating device, which is favorable in assembling property and susceptible of less wear and can be made small in size and inexpensively conformed to many kinds of machines.
In order to attain the above objects, a monolever operating device according to the invention comprises a monolever capable of inclining in a two-dimensional optional direction conformed to at least a front and rear direction and a right and left direction, drive signal generating means received in a drive signal generating body to output two drive signals to components in the front and rear direction and in the right and left direction in accordance with an orientation and an amount of inclination of the monolever, a universal joint mounted on the drive signal generating body to support the monolever in an inclinable manner, a mount plate for mounting the drive signal generating body mounted thereto to a vehicle body, a boot provided between the monolever and the mount plate to cover the drive signal generating means, and a monolever bearing member provided on an upper surface of the mount plate and provided with lever bearing portions and boot holding portions alternately arranged adjacent to each other in a circumferential direction.
In this case, the monolever bearing member comprises a press formed part of a low-carbon steel material subjected to carburization.
Also, the monolever bearing member may comprise lever bearing portions provided perpendicular to a surface thereof being mounted on the mount plate and boot holding portions provided in parallel to the surface to hole the boot.
Also, slits may be provided between the lever bearing portions and the boot holding portions of the monolever bearing member.
Also, the lever bearing portions of the monolever bearing member may be formed to be arcuate Ra as viewed in plan view.
With the above constitution, the monolever operating device comprises a mount plate for mounting the drive signal generating body to a vehicle body and a monolever stopping member for stopping an inclination of the monolever, and the arrangement is alternate on a circumference, whereby insertion of the boot into the monolever stopping member is facilitated and assembling is made easy to achieve reduction in manhour in assembling.
Also, the monolever stopping member is made a single part whereby the monolever stopping member having a plurality of configurations can be subjected to drawing in one step to reduce cost for a metallic mold. Also, the monolever stopping member is made a single part whereby a monolever operating device capable of conforming to many kinds of machines can be provided by preparing a plurality of monolever stopping members having different sizes.
The monolever bearing member is formed from a low-carbon steel material subjected to carburization to be increased in hardness, so that the lever bearing portions are reduced in wear, by which the performance can be prevented from changing after use over a long term. Also, fabrication is made by means of press work to thereby achieve reduction in manhour in work.
The monolever bearing member is composed of the lever bearing portions and the boot holding portions, so that a demand for a design value with a different inclination can be accommodated for by modifying a length of a sheet material for the lever bearing portions. Also, even when a length of the lever bearing portions is modified at the time of press work, a metallic mold can be readily manufactured to reduce cost for manufacture of the mold and facilitate management of the mold.
With the monolever bearing member, the slits are provided between the lever bearing portions and the boot holding portions of the monolever bearing member, whereby the lever bearing portions and the boot holding portions can be arranged alternately adjacent to each other in a circumferential direction, and press work can be performed with ease. At this time, the slits are extended inward from bent portions to thereby facilitate drawing.
The lever bearing portions of the monolever bearing member are formed to be arcuate as viewed in plan view, so that the lever bearing portions are made high in allowable bending stress and so can be made thin to achieve miniaturization.
As described above, the monolever bearing member is structured such that the lever bearing portions and the boot holding portions are arranged alternately adjacent to each other in a circumferential direction with the slits therebetween, a low-carbon steel material is subjected to carburization for an increased hardness, and the lever bearing portions are formed to be arcuate. Thereby, even when being made small in plate thickness, the monolever bearing member is enhanced in abrasion resistance and allowable bending stress, mounting of the boot is facilitated, the same metallic mold complies with a demand for a variety of inclinations, and press work is enabled, whereby work and assembling are facilitated, miniaturization is achieved, and a change in performance after use over a long term can be decreased.