JPH061464U - How to fix the "float" position of the work equipment control lever - Google Patents

Abstract

(57) [Summary] [Purpose] Mechanical detents and "floating" are placed in the "floating" position of the working machine operating lever for vehicle-type construction machinery.
An electric "floating" position detection switch is provided to prevent the engine from starting in the position, which complicates the assembly work. Therefore, we provide a method for fixing the "floating" position of the work equipment operation lever, which is easy to assemble and adjust. [Structure] A bracket 9 is fixed to a working machine operating lever 8, and when the working machine operating lever 8 is shifted to a “floating” position, the bracket 9 is attracted to an electromagnet 10 whose power source is a generator driven by an engine. Fix the work implement operating lever 8. When the engine stops, the magnetic force of the electromagnet 10 becomes zero because the generator also stops, and the working machine operating lever 8 returns to the "neutral" position by the self-recovery function. In the main fixing method, only the electromagnet needs to be attached, the structure is simplified, and the number of assembling steps can be reduced.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a vehicle-type construction machine equipped with a pilot type directional control valve for working machine control, and more particularly to a method for fixing a "floating" position of a working machine operating lever.

[0002]

[Prior art]

 As shown in Fig. 2, vehicle-type construction machines such as bulldozers and dozer shovels control the operation, stop, acceleration, deceleration, and operation direction of hydraulic cylinders 2 that drive working machines such as blades and buckets. A direction switching valve 3 for switching the flow of pressure oil is provided in the middle of the circuit connecting the main pump 1 which is the source and the hydraulic cylinder 2. This directional valve 3 is generally of the spool type and has a structure that can be switched among four positions: "up", "neutral" (indicated as N in FIG. 2), "down", and "float". The “upper”, “neutral”, and “lower” are provided to raise, hold, and lower the work machine, respectively, and for “floating”, the head side and bottom side of the pump, tank, and hydraulic cylinder. Since each of the ports communicate with each other, the force acting on the work machine is only its own weight. Therefore, when an external force is applied to the earthmoving machine in the “floating” position, the work machine can move freely in response to this, and when an earthmoving finishing work is performed in reverse using a bulldozer, dozer shovel, etc. "The position is used.

The operation of the work machine is performed by the operator manually operating the work machine operation lever 8 provided near the driver's seat. However, in order to reduce the operator's fatigue by reducing the lever operation force, the work machine operation lever 8 is operated. The pilot valve 4 is moved by the machine operation lever 8 and the pilot pressure output by the pilot valve 4 is applied to the spool end of the directional control valve 3 according to the operation amount of the work machine operation lever 8 to operate the main valve. The spool position is switched. Pressure oil is supplied to the pilot valve 4 from a pilot pump 7 dedicated to the pilot valve, which is provided separately from the main pump 1 that supplies pressure oil to each hydraulic actuator via the direction switching valve 3. Further, the working machine operating lever 8 has a self-returning function by a return spring inside the pilot valve, and when the operating lever 8 is released, it automatically returns to the "neutral" position. However, in the “floating” position, the mechanical detent 11 using a steel ball and a spring acts, and the convex portion 12a of the shaft 12 is locked by the steel ball, so that the work machine operating lever 8 is released. However, it remains fixed in the "float" position.

In a construction machine equipped with such a directional control valve and a working machine operating lever, for example, a bulldozer, if the engine is stopped for some reason while the blade is raised from the ground, the main pump and pilot pump The main valve spool will automatically return to the “neutral” position by the return springs installed at both ends of the spool, and the directional control valve will not move no matter how the operating lever is operated. , So the blade doesn't move either. Then, when the work implement operating lever happens to enter the “float” position, the mechanical detent acts and the work implement operating lever is fixed in the “float” position. When the engine is restarted in this state, pressure oil supply from the main pump and pilot pump is restarted, and the spool of the directional control valve moves from "neutral" to "down" to "float". Therefore, the blade will drop to the ground when the engine restarts, which is extremely dangerous because it is an unintended movement by the operator. Therefore, in order to avoid such a danger, a means for detecting the "floating" position is provided so that the engine cannot be restarted when the work implement operating lever is in the "floating" position. In the case of the human power system in which the work implement control lever is directly connected to the spool of the direction switching valve without using pilot pressure, the work implement control lever can be operated to the “float” position even after the engine is stopped. , The blade can be lowered to ground, so the above danger does not occur.

[0005]

[Problems to be solved by the device]

 In a conventional bulldozer equipped with a pilot type directional control valve, when the work implement operating lever 8 is fixed to the “floating” position, the proximity switch 13 provided in the vicinity of this position actuates the work. Detects that the machine control lever has entered the “floating” position. The proximity switch 13 uses a battery mounted on the bulldozer as a power source, and the output signal thereof is input to the fuel cutoff valve of the engine so that the engine cannot be started in this state. Although there is no particular problem regarding the function of such a risk avoidance means and its safety, as described above regarding the “floating” position, the mechanical detent and the electric “floating” position detecting means function independently of each other. Therefore, adjustment is required for each, and assembly work becomes complicated. The present invention has been made in view of the above-mentioned conventional problems, and has a pilot type working machine control directional control valve, and the directional control valve has a "floating" position. It is an object of the present invention to provide a method for fixing the "floating" position of the working machine operation lever, which is easy to assemble and adjust.

[0006]

[Means for Solving the Problems]

 In order to achieve the above object, a method for fixing a "floating" position of a working machine operating lever according to the present invention has a pilot type working machine control directional control valve, and the directional switching valve has a "floating" position. In the construction machinery for vehicles, when the working machine operating lever is shifted to the “floating” position, the working machine operating lever is attracted to the electromagnet whose power source is the generator driven by the engine.

[0007]

[Action]

 According to the above configuration, since the electromagnet that uses the generator driven by the engine as the power source is used as the means for fixing the work implement operating lever to the “floating” position, the work implement operating lever is set to the “float” position. Shifting to, the work implement operating lever is attracted to the electromagnet and locked in the "float" position. When the engine is stopped in this state, the magnetic force of the electromagnet becomes zero, and the work implement operating lever returns to the "neutral" position by the self-return function of the return spring. Also, no matter how the operator operates the work implement operating lever when the engine is stopped, the magnetic force of the electromagnet is zero, so the work implement operating lever cannot be fixed to the “float” position. Therefore, the work implement operating lever is always in the "neutral" position when the engine is started, and the "floating" position detection means such as a proximity switch can be eliminated.

[0008]

【Example】

 An embodiment of a method for fixing a "floating" position of a working machine operation lever according to the present invention will be described below with reference to the drawings. FIG. 1 is an explanatory view of a method for fixing the work equipment operation lever to the “floating” position. A direction switching valve 3 is provided in the middle of the hydraulic circuit from the main pump 1 to the hydraulic cylinder 2, and the pilot valve 4 and the direction switching valve are provided. Pilot lines 5 and 6 are provided between the spool and both ends of the valve 3, respectively. The pilot valve 4 uses a pilot pump 7 as a hydraulic pressure source, and outputs a pilot pressure that is substantially proportional to the operation amount of the work machine operating lever 8. A bracket 9 made of a magnetic material is fixed to the working machine operating lever 8, and an electromagnet 10 is arranged at a position where the bracket 9 is attracted when the working machine operating lever 8 is shifted to a "floating" position. The electromagnet 10 functions as a power source using a generator mounted on an engine (not shown). Therefore, the electromagnet 10 does not operate when the engine is stopped. In FIG. 1, N displayed on the working machine operating lever 8 and the directional control valve 3 indicates "neutral".

The main pump 1, the pilot pump 7, and the generator are all driven by the engine. When the operator moves the work implement operation lever 8 to a desired position, the pilot pressure corresponding to the lever operation amount acts on the spool end of the directional control valve 3, the spool slides, and the main pump 1 discharges. Pressure oil to be sent to the hydraulic cylinder 2. The “float” position is at the position where the work implement operating lever 8 is tilted to the maximum as in the conventional case. When the work implement operating lever 8 is moved to the “float” position, the bracket 9 is attracted to the electromagnet 10. The work equipment operating lever 8 is fixed to the "floating" position.

When the engine stops for some reason, the generator also stops, so the electromagnetic force of the electromagnet 10 becomes zero. Therefore, the working machine operating lever 8 fixed to the "floating" position by the electromagnetic force returns to the "neutral" position by the self-return function. Further, since the electromagnet 10 does not operate while the engine is stopped, even if the work implement operating lever 8 is operated to the "floating" position, it will return to the "neutral" position when the hand is released. Therefore, when the engine is restarted, the work implement operating lever 8 is always in the "neutral" position, so that the "floating" position detection switch as in the prior art is unnecessary. As described above, the "floating" position detection switch can be eliminated, and the adjustment work at the time of assembling can be done only by adjusting the arrangement position of the electromagnet 10, and the number of assembling steps can be reduced.

The present invention is not limited to bulldozers and dozer shovels, and has various types of construction machines, industrial vehicles, etc. that have a pilot type directional control valve for working machine control and the directional control valve has a “floating” position. Can be applied to.

[0012]

[Effect of device]

 As described above, according to the present invention, in a vehicle construction machine having a pilot type working machine control directional control valve and the directional control valve having a "floating" position, the working machine operating lever is provided. When shifting to the “float” position, the work machine operating lever is attracted to the electromagnet that uses the generator driven by the engine as the power source. Therefore, when the engine is stopped, the work machine operating lever must be in the “neutral” position. Return to yon. Therefore, when the engine is restarted, there is no risk that the working machine will be driven against the operator's will, and the safety of the vehicle-based construction machine can be improved. Also, the "floating" position detecting means such as a proximity switch, which has been conventionally mounted, becomes unnecessary, and by eliminating this, the only adjustment work at the time of assembly is the adjustment of the position of the electromagnet. As described above, regarding the “floating” position, by adjusting only the arrangement position of the electromagnet instead of adjusting both the mechanical detent and the detection switch, the structure is simplified and the number of assembly steps can be reduced.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of a method of fixing a work implement operating lever to a “floating” position.

[Fig. 2] "Floating" the work implement operating lever by the conventional technique
It is explanatory drawing at the time of fixing to a position.

[Explanation of symbols]

 3 Direction switching valve 4 Pilot valve 5, 6 Pilot line 8 Working machine operating lever 10 Electromagnet

Claims (1)

[Scope of utility model registration request] 1. A vehicle-type construction machine or the like having a pilot type working machine control directional control valve, and the directional control valve having a "floating" position, wherein a working machine operating lever is shifted to a "floating" position. In this case, the working machine operating lever is fixed to the "floating" position by causing the working machine operating lever to be attracted to an electromagnet powered by a generator driven by an engine.