JPS6224016Y2 - - Google Patents

Description

[Detailed description of the invention] This invention has operating levers that control the drive devices of each operating part arranged in parallel on the chassis, and the speed control lever of the engine that supplies power to each drive device is rotated to a constant intermediate speed position. The present invention relates to a self-propelled working machine such as a power shovel that is provided with a movable first operating mechanism and a second operating mechanism that can rotate the speed control lever to a maximum speed position.

The noise emitted by such self-propelled work equipment is caused by the engine driver being a very large factor, and each operating part of the work equipment is ultimately driven by the engine, so the first operating mechanism By controlling the engine speed to a certain intermediate speed or lower, it is possible to perform low-noise work in urban areas, or by operating the second operating mechanism or this and the first operating mechanism, it is possible to perform low-noise work in large areas outside of urban areas. Although it is possible to drive at high speeds at work sites, etc., when operating the second operating mechanism when working in urban areas, or when working while driving at low speeds, it may generate high noise or cause power loss due to engine revving. There is a risk that this may occur.

The present invention focuses on the fact that the required engine output is relatively small during work and large when driving, and while working by operating operating levers other than the driving control operating lever, the engine output at a constant intermediate speed or higher is This problem is attempted to be solved by stopping the operation of the two operating mechanisms so that the engine speed cannot be increased above a certain intermediate speed.

In the present invention, the second operating mechanism is provided with a transmission control device that has a normal position that allows its operation and a switching position that stops its operation above a certain intermediate speed, and is interlocked and connected to other operating levers other than the travel control operating lever. The present invention is characterized in that a device is provided for switching the transmission control device to a switching position when any of the other operating levers is rotated to a drive position.

An illustrated embodiment in which the present invention is applied to a hydraulic power shovel will be described below. In Figs. 1 to 4, 1 is a chassis mounted rotatably on the support frames of the crawler traveling devices 2, 2 on both sides, and 3 is the chassis 1.
5 is an arm cylinder that rotates an arm 6 that is pivoted on the tip of the boom; 7 is a bucket that rotates a bucket 8 that is pivoted on the tip of the arm; cylinder, 9
1 indicates a driver's cab mounted on the chassis 1, and 10 a high-speed diesel engine mounted on the chassis. Inside the driver's cab 9 are directional control valves V ₁ for controlling the drive hydraulic motors of the crawler traveling devices 2 on both sides, respectively. , V ₁ , which control the boom cylinder 3 and bucket cylinder 7, respectively, by sandwiching the operation levers 11, 11 of the directional control valves V ₂ ,
Operating levers 12 and 13 of V ₃ and operating levers 14 and 15 of directional control valves V ₄ and V ₅ that respectively control the arm cylinder 5 and the chassis rotation hydraulic motor are pivoted by a shaft 16, and at least the operating levers 11, 11 are always urged to return to the illustrated drive stop position by neutral position return springs in the corresponding directional switching valves. 17 is a connecting rod between the lower part of each operating lever and the spool of the opposite direction switching valve.

The engine 10 drives two constant displacement hydraulic pumps of equal capacity, one of which drives a third hydraulic pump.
Pressure oil is supplied to the directional control valves V ₁ , V ₂ , and V ₃ in the lower half of the figure, and the other hydraulic pump supplies pressure oil to the directional control valves V ₁ , V ₄ , and V ₅ in the upper half of the figure. The speed control lever 18 of the mechanical governor attached to the engine is limited in its rotation range between the idling position O and the maximum speed position M, and is always kept at the idling position O by the governor spring 19. is being encouraged to return.

The second operating mechanism includes a foot-operated accelerator lever (accelerator pedal) 21 whose intermediate portion is pivoted 20 to the vehicle chassis 1.
A master cylinder 24 is connected to a piston rod 23 via a connecting rod 22, and a single-acting power cylinder 26 is supplied with hydraulic pressure from the master cylinder through an oil passage 25. The piston rod 27 of the power cylinder is connected to a connecting rod 28. The connecting portion is connected to the speed control lever 18 through a long hole 28a provided at the rear end of the connecting rod 28, and a pin 29 fixed to the speed control lever through the long hole 28a.
One end is fitted so that the pin 29 is located approximately at the front end of the elongated hole 28a as shown in the figure in the idling state, and in this state, the speed control lever 18 is temporarily rotated to the maximum speed position M. The length of the elongated hole 28a is determined so that the power cylinder 26 does not expand even if the power cylinder 26 is extended. The master cylinder 24 and the power cylinder 26 each have built-in compression springs 30 and 31 that always urge the piston rod to return to the illustrated idling position, and the piston on the master cylinder side can communicate between the cylinder chambers on both sides thereof. A check valve 32 is attached.

In the first operating mechanism, the speed control lever 18 is connected via a connecting rod 35 to a manual accelerator lever 34 whose intermediate portion is pivoted 33 to the chassis 1, and the connecting portion is connected to the rear end of the connecting rod 35. Long hole 28a
A long hole 35a exactly the same as that shown in FIG. 1 is provided, and the other end of the pin 29 is fitted into the long hole. Although the connecting rod 35 is shown bent for convenience of illustration, it is actually a straight rod parallel to the connecting rod 28. Therefore, the speed control lever 18 can be independently rotated in the speed increasing direction by either the accelerator levers 21 or 34, but the accelerator lever 34 is
8 from the idling position O to the constant intermediate speed position N
The arc-shaped scale plate 36
The range of rotation is restricted by the accelerator lever 34, and the accelerator lever 34 is fixed at any rotational position by a friction mechanism provided at its pivot portion. Furthermore, accelerator lever 2
1 and 34 are arranged on the vehicle chassis 1 so as to be operable simultaneously with any of the operation levers 11 to 15.

The transmission control device includes an electromagnetic switching valve 37 inserted in the middle of the oil passage 25, and the electromagnetic switching valve 37 has two positions as shown in the figure: a normal position where the power cylinder 26 is communicated only with the pressurized cylinder chamber of the master cylinder 24; A switching position is provided in which the power cylinder 26 is communicated only with the tank T.

Therefore, in the operating circuit 38 of the electromagnetic switching valve 37, when any of the operating levers 12, 13, 14, 15 other than the driving control operating lever 11 is rotated to either the forward or backward drive position, the operating lever 38 is closed. A normally open switch (limit switch) 39 is inserted. 40 indicates a power supply for the circuit 38.

The device for switching the limit switch 39 is pivotally supported 41 on the chassis 1, and the limit switch 39 is switched at the lower end.
The upper plate-like arm 4 of the bell-crank-like lever 42 that closes the
2b, operating levers 12, 13, 14, 15, respectively.
Four inverted T-shaped levers 44 whose intermediate portions are pivoted 43 to the chassis 1 are brought into contact with each other as shown in FIG. They are connected by connecting rods 45, respectively. Reference numeral 46 denotes a spring that constantly presses and biases the bell crank-shaped lever 42 against the inverted T-shaped lever 44.

Therefore, even if any of the operation levers 12, 13, 14, 15 is rotated to the forward or backward drive position, the bell crank-shaped lever 42 always rotates clockwise (in FIG. 1) to switch to the normally open switch. The switch 39 will be opened by closing the switch 39 and returning the operating lever to the drive stop position (neutral position).

According to the above-mentioned configuration, while the vehicle is traveling by operating only the travel control operation lever 11, the switch 39 remains open as shown in the figure, and the changeover valve 37 is held in a normal position to communicate the master cylinder 24 and the power cylinder 26.
By rotating the master cylinder 1 against the elastic force of the spring 30, the oil in the master cylinder is forced to flow to the power cylinder 26.
31.
The speed control lever 18, which is in the idling position O, can be rotated to the maximum speed position M as required to run the self-propelled working machine at high speed.

When one of the operating levers 12, 13, 14, 15 is rotated to the drive position to start work, the switch 39 is closed and the switching valve 37 is switched to the upper position (switching position) in FIG. Since the power cylinder and the connecting rod 28 are returned to the illustrated position by the elasticity of the spring 31, the speed control lever 18 is also returned to the idling position by the spring 19. On the other hand, when the operating force of the accelerator lever 21 is removed, the master cylinder 24 opens the check valve 32 and returns to the illustrated position by the elasticity of the spring 30, sucking oil from the tank T into its pressurized cylinder chamber.

In the above embodiment, the second operating mechanism is a hydraulic transmission mechanism, and the transmission control device or the electromagnetic switching valve 3
Although the power cylinder 26 is automatically returned to the idling position shown in the figure at the switching position 7, it is generally recommended to reduce the engine speed to a certain intermediate speed or less when the self-propelled work machine starts traveling or immediately before it stops traveling. Therefore, the transmission control device may be configured to stop operation above a certain intermediate speed in the switching position.

FIG. 5 shows an example of this, in which the second operating mechanism sequentially moves between the intermediate part of a foot-operated accelerator lever (accelerator pedal) 48 whose lower end is pivoted 47 to the chassis 1 and the connecting rod 28, and the connecting rod 49. , 50, and the connecting rod 50 is slidably supported on the support portions 1a and 1b provided on the chassis 1, and the transmission control device includes a one-way engaging pawl 51 projecting from the lower end of the connecting rod 50. and,
A double rod-shaped piston-shaped control rod 53 slidably passes through a cylindrical guide 52 attached to the chassis 1 on the tip end side of the one-way engagement pawl 51 or the moving side when the engine speed increases; 5
3 to the normal position shown in the figure.

The one-way engagement claw 51 has a pressing force in the axial direction of the connecting rod 50 (pressing force to the right in the figure) that acts on the tip of the claw.
The control rod 53 is held in the position shown in the figure, but is supported by an appropriate spring so as to be recessed into the connecting rod 50 when the rear side receives a pressing force in the opposite direction, and the lower part of the control rod 53 is Equipped with a long hole through which the rod 50 passes,
The stopper 53b that closes the lower end of the elongated hole is movable up and down between a normal position below the tip of the one-way engagement claw 51 and a switching position where it can engage with the one-way engagement claw.

The device for switching the transmission control device includes four inverted T-shaped levers 44 that are interlocked and connected to the operation levers 12, 13, 14, and 15, respectively, as in the previous embodiment, and one end of which is in contact with the full inverted T-shaped lever. A pin 53a attached to the upper end of the control rod 53 is attached to the lever 56, which is formed into a plate-like arm and whose intermediate portion is pivoted to the chassis 1.
It engages with a long hole drilled at the other end.

Reference numeral 57 denotes a return spring for the accelerator pedal 48, and the return spring 57 closes the head 5 of the connecting rod 50 when no external force is applied.
0a is engaged with the support portion 1a, and the distance between the one-way engagement pawl 51 and the control rod 53 is determined by the sliding of the connecting rod 50 when the speed control lever 18 is rotated from the idling position O to the constant intermediate speed position N. equal to the dynamic displacement. In addition, in Figure 5, the first
Components with the same reference numerals as in FIGS. 3 to 3 indicate corresponding components.

According to the above configuration, when driving by operating the driving control operation lever 11, the control rod 53 is always in the illustrated position, so the speed control lever 18 can be freely rotated to the maximum speed position M by the accelerator lever 48. It is possible. However, when performing digging work by rotating any of the operating levers 12 to 15 to the drive position,
The lever 56 is rotated as shown by the chain line by the inverted T-shaped lever 44 interlocked with the operating lever, and the control rod 53 is rotated against the elasticity of the spring 54, so that the stopper 53b engages the one-way engagement pawl 51. Since the claws are pulled up until they are opposite to each other, even if the accelerator lever 48 is operated, the claws will not move to the stopper 53.
It can only be rotated until it engages with b, and it is impossible to increase the engine speed above a certain intermediate speed.

Therefore, according to the present invention, the engine can be brought to maximum speed only when operating only the travel control operating lever, but when the other operating levers are operated to the drive position, the engine is kept at a constant intermediate speed. It is possible to eliminate the risk of accidentally emitting high noise when working in a city area or while driving at low speed.

[Brief explanation of the drawing]

FIG. 1 is a side view schematically showing an embodiment of the present invention;
Figure 2 is an X sectional view of Figure 1, Figure 3 is a perspective view of the vicinity of the operating lever, Figure 4 is a side view of the self-propelled work machine, and Figure 5 is a side view of the self-propelled work machine.
The figure is a side view schematically showing another embodiment. 1... Vehicle chassis, 11... Operating lever for driving control, 1
2, 13, 14, 15...operation lever, 18...speed control lever, 21, 48...foot-operated accelerator lever of the second operating mechanism, 24...master cylinder, 26...power cylinder, 34...th 1. Manual accelerator lever of operation mechanism, 37... Solenoid switching valve, 39... Normally open switch.

Claims (1)

[Scope of utility model registration request] A first operating mechanism includes operating levers arranged in parallel on the vehicle chassis to control the drive devices of each operating part, and is capable of rotating a speed control lever of an engine that supplies power to each of the drive devices to a constant intermediate speed position; In a self-propelled work machine equipped with a second operating mechanism capable of rotating a speed control lever to a maximum speed position,
The second operating mechanism is provided with a transmission control device that has a normal position that allows its operation and a switching position that stops its operation above a certain intermediate speed, and is interlocked and connected to other operating levers other than the traveling control operating lever. An engine speed control device for a self-propelled working machine, comprising a device for switching the transmission control device to a switching position when any of the other operating levers is rotated to a drive position.