JPH0455104Y2 - - Google Patents

Description

[Detailed Description of the Invention] Industrial Application Field The present invention relates to a locking mechanism for a lever that controls a limit switch of a construction machine.

2. Description of the Related Art A lever 22 is provided on the side of a driver's seat 21 of a construction machine, as shown in FIG. The lever 2
Reference numeral 2 operates a limit switch 23, whose base end is fixed to a boss 27 fixed to one side of a pin 26 fitted into a bearing 25 fixed to the side of a box 24 housing a hydraulic device. A lever 28 is fixed to the other side, and a spring 3 is inserted between the bracket 29 fixed to the tip of the lever 28 and the box 24.
0 is attached, and by pulling the lever 28 to one side with the spring 30, the lever 22 is raised upward and held in that position, and the limit switch 23 is activated.
The limit switch 23 is kept in a constant state of ON or OFF, and when switching the limit switch 23, the lever 22 is tilted forward. As the lever 28 integrated with the lever 22 is rotated, the center line of action of the spring 30 is aligned with the pin 22. By crossing the center of the lever 28
The direction of the tension acting on the lever 22 is reversed, so that the lever 22 can be locked in the direction in which it is pushed down. Also,
A cam 31 is fixed to one side of the pin 26,
The cam 31 moves the box 2 in response to the rotation of the pin 26.
A limit switch 23 connected to the switch 4 via a bracket 32 is actuated. Therefore, when the driver operates the lever 22, the pin 26 rotates, and the cam portion 31 engages the limit switch 23.
At the same time, the lever 28 integrated with the pin 26 is pulled in a certain direction by a spring 30, so that the lever 22 operated by the driver is held at the operated position.

Problems to be Solved by the Invention As described above, the operating mechanism using the lever 22 for operating the limit switch 23 is provided with a locking mechanism using the spring 30 and the lever 28 in order to lock the position of the operated lever 22. However, this lever 28 and spring 30 require a considerable amount of space. It is preferred that the box 24 be as compact as possible, and therefore it is preferred that these locking mechanisms occupy as little space as possible. The object of the present invention is to provide a lever locking mechanism that meets the above requirements.

Means for Solving the Problems The means of the present invention taken to solve the above problems are (a) A lever provided on the side of the driver's seat, and a lever that is integral with the lever and pivoted on a pin. It has a boss and a cam surface provided on its outer periphery, and the cam surface of the boss operates a limit switch when a lever is operated.

Robos has two cam surfaces separated by the operating angle of the lever.

(c) The tip of the piston of the push-up device, which has a piston, a spring that pushes it, and an adjustment mechanism for the spring, is pressed against one cam surface.

It is.

How it works: On the boss that is integrated with the lever that has a cam surface that operates the limit switch, two cam surfaces are provided at the same angle as the operating angle of the lever, and the piston is pressed against this with a spring to lock the rotation of the boss. By doing this, the locking mechanism for boss rotation became simple and compact. In addition, since there are fewer exposed parts, there is less risk of failure or damage.

Embodiments Hereinafter, embodiments of the present invention will be described in detail based on the drawings.

A lever 1 is used to operate a limit switch 4 for controlling a hydraulic system installed inside a box 3 installed on the side of the driver's seat 2, and extends forward from the box 3. It is further bent upward and has a grip 5 at the top. The base end portion of the lever 1 is fixed to the intermediate portion of the boss 6 slightly to the side. The boss 6 is rotatably supported by a pin 7, and the pin 7 is supported on both sides by brackets 9 fixed to a side plate 8. As shown in FIG. 3, the boss 6 has three notches on the same circumference on the outer peripheral surface of its intermediate portion to form three cam surfaces A, B, and C. The first cam surface A and the second cam surface B press the piston 11 of the pressing device 10 and press the lever 1.
The third cam surface C is for operating the limit switch 4. The third cam surface C is for operating the limit switch 4. Cam surface A and cam surface B both form a surface that is tangential, that is, perpendicular to the radial line, and the angle θ formed by the two cam surfaces A and B is the same as the operating angle θ of lever 1. When the lever 1 is pulled up to the upper limit, the cam surface A correctly contacts the upper surface of the piston 11, and when the lever 1 is pushed down to the lower limit, the cam surface B
The piston 11 is made to properly abut against the upper surface of the piston 11. The pressing device 10 includes a cylindrical body 12 and a piston 1 that is slidably inserted into the cylindrical body 12 and slightly protrudes from the upper part.
1 and a spring 13 fitted below the piston 11.
The bolt 14 and nut 15 are screwed into the lower part of the cylindrical body 12 to adjust the pushing force of the spring 13, and are fixed to the lower part of the side plate 8. The cam surface C is provided on the substantially opposite side to the cam surface B, and is in contact with the operating portion 16 of the limit switch 4.

Note that 17 is a notch hole in the box 3, and 18 is a hydraulic system operating lever.

The present invention is constructed as described above, and to explain the actual operation, when the lever 1 is tilted forward as shown in FIG. The upper end surface of the piston 11 is in contact with the upper end surface of the piston 11 in the correct state. piston 1
Since the lever 1 is strongly pressed against the cam surface B by the operating force of the spring 13, the boss 6 is restrained by the piston 11 and cannot rotate freely, and the lever 1 maintains its state of being tilted forward. do. There is a cam surface C on the opposite side of the boss 6 to the cam surface B, that is, on the upper side, and when the cam surface B is in contact with the piston 11,
The cam surface C comes into contact with the lower end of the actuating part 16 of the limit switch 4, and the actuating part 16 is made to contact both the cam surface C and the outer peripheral surface d of the boss 6 alternately. Limit switch 4 is turned OFF when contact is made, and turned ON when contact is made on the outer circumferential surface d.
Therefore, when the lever 1 is tilted forward and the cam surface B is in contact with the upper end surface of the piston 11, the limit switch 4 is
OFF, and the boss 6 is locked by the piston 11, so the limit switch 4 is
Retains the OFF state.

Next, if you want to turn on the limit switch 4, pull the lever 1 upward. Since the boss 6, which is integral with the lever 1, is locked by pushing its cam surface B with the piston 11, when the lever 1 is to be pulled up, the boss 6 must be rotated with a greater force. boss 6
The outer peripheral surface d of the piston 11 resists the force of the spring 13.
Push down and rotate to the adjacent cam surface A. Since the cam surface A of the boss 6 is set in advance so that the end point of the rotation of the lever 1 is exactly when the cam surface A and the upper end surface of the piston 11 are in proper contact with each other, the cam surface A of the boss 6 corresponds to the cam surface explained earlier. Piston 1 as in case B
It is pressed and locked at 1 and will not rotate any further. When the boss 6 rotates, the actuating portion 16 of the limit switch 4 comes into contact with the outer circumferential surface d of the boss 6, and the actuating portion 16 is pushed up slightly by the outer circumferential surface d, and the limit switch 4 is turned on. Since the boss 6 is locked by the piston 11 and the spring 13 and does not rotate any further, the limit switch 4 remains in the ON state when the lever 1 is pulled up.

The force required to operate the lever 1 or the force required to lock the lever 1 from rotating by itself depends on the shape of the cam surfaces A and B of the boss 6, and
It is determined by the operating force of the spring 13. Spring 13
The operating force can be easily adjusted by operating the bolt 14. The shape of the boss 6 should of course be set in advance, but the shape of the boss 6 from the cam surfaces A and B
It is related to the difference between the distance from the center O of the boss 6 to the center of the boss 6, and the distance from the middle part e between the cam surfaces A and B on the outer peripheral surface of the boss 6 to the center of the boss 6, so the larger the difference, the greater the locking action. However, a large amount of operating force is required.

Effects of the invention As described above, the present invention provides two cam surfaces having an angle equal to the operating angle of the lever on the boss that is integrated with the lever that operates the limit switch, and presses the piston against the cam surfaces with a spring to open the boss. Since the rotation is locked, the lever locking mechanism is simple and compact. In addition, the number of exposed parts is reduced, reducing the risk of failure, damage, etc.

[Brief explanation of the drawing]

Figure 1 is a front view of the present invention, Figure 2 is a side view, Figure 3 is a sectional view of the main parts of the present invention, Figure 4 is a front view of the operator's cab with the present invention installed, and Figure 5 is a side view. Figure, 6th
7 is an explanatory diagram of the operating situation of the present invention, FIG. 8 is a diagram showing the conventional one, and FIG. 9 is GG in FIG. 8.
10 is a view taken along the line H--H in FIG. 8. 1... Lever, 4... Limit switch, 6...
...Boss, 7...Pin, 10...Pushing device, 11...
...Piston, 13...Spring, 14...Bolt, A
...Cam surface, B...cam surface, C...cam surface.

Claims (1)

[Scope of utility model registration request] It has a lever, a boss integrally supported by the lever, and a cam surface provided on the outer periphery of the lever, and when the lever is operated, the cam surface of the boss engages with the cam surface to operate a limit switch. In this construction, the boss is provided with two cam surfaces separated by the operating angle of the lever, and one of the cam surfaces is pressed against the tip of the piston of a lifting device consisting of a piston, a spring, and its adjustment mechanism. Mechanical lever lock mechanism.