JPS6246605Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to an improvement of a mechanical operating mechanism in a foot-operated band brake device or the like.

Conventionally, a foot-operated band brake device for a hoisting drum of a crane includes, for example, a foot pedal 1, rods 3, 12, 14, a lever 6, as shown in FIG.
Equipped with a link type brake actuation mechanism consisting of 13 and 15, the brake wheel 1 is activated by pressing the foot pedal 1.
Apply tension to band 16 wrapped around band 1.
A brake device is used in which rotation of a hoisting drum (not shown) is braked by friction between the brake wheel 6 and the brake wheel 17. However, with the conventional brake actuation mechanism, in order to brake the large load applied to the hoisting drum, a pedal force corresponding to the load is required, and while the operator can directly feel the braking, it relies on the operator's pedal force, so a large brake force is required. It was difficult to gain strength and fatigue was inevitable. For this reason, a hydraulic brake actuation mechanism using a brake master cylinder is also used, but while this conventional hydraulic brake actuation mechanism does not cause operator fatigue when operating the brakes, it is difficult to directly feel the braking force, and it is difficult to The problem was that it was necessary to get used to using the device in order to obtain a precise braking sensation.

The present invention was devised to solve the problems of the conventional device described above, and it maintains the advantage of the conventional mechanical brake actuation mechanism of easily obtaining an appropriate braking feeling, while increasing the brake operating force. To provide a brake device with reduced pressure, a balance arm is interposed between a rotary lever and a rod of a link mechanism that can operate the brake by operating a foot pedal, and a substantially central portion of the balance arm is provided. It is characterized in that it is connected to the foot pedal side rod, and that one end is connected to the rotating lever across the connecting part, and the other end is connected to a servo valve for cylinder control that operates the brake. .

The present invention will be described below with reference to embodiments shown in FIGS. 2 to 5.

Figure 2 is a schematic diagram of the present invention applied to a foot-operated band brake device for the hoisting drum of a crane, Figure 3 is an enlarged view of the main part of Figure 2, and Figure 4 shows the servo valve in Figure 3. FIG. 3 is a diagram showing a connection relationship of hydraulic cylinders.

Reference numeral 1 denotes a foot pedal pivotally connected to the upper revolving body 2 of the crane, a rod 3 is pivotally connected to the pedal 1, and the other end of a helical spring 4 whose one end is attached to the upper revolving body 2 side. is attached, and the pedal 1 is always biased by the spring 4 to be held at the solid line position.

5 is a substantially L-shaped balance arm;
The substantially central point a of the rod 3 is pivotally connected to the rod 3, and one end point b is connected to the rotating lever 6 and the other end point c are each pivotally connected to a link 8 connected to the spool type servo valve 7.

The rotary lever 6 is rotatably supported at its center by a rotary shaft 9, and is connected to a hydraulic cylinder 10 on the balance arm 5 side, sandwiching the rotary shaft 9 of the lever 6. A rod 12 is pivotally attached to the side of the link 11 opposite to the balance arm 5, and the rod 12 is connected to a lever 13, a rod 14, and a lever 15, which are rotatably supported. The other end of the brake band 16 is connected to the other end of the brake band 16, which has one end fixed to the upper revolving body 2 side. 17 is a brake wheel around which the brake band 16 is wound.

The spool type servo valve 7 and the hydraulic cylinder 10
As shown in FIG. 4, the port 18 of the spool type servo valve 7 is connected to a hydraulic power source P such as a hydraulic pump capable of constantly supplying a constant pressure, the port 19 is connected to a tank 20, and the port 21 is connected to a pipe. It is connected via a passage 22 to the rod extrusion side of the hydraulic cylinder 10. Therefore, the spool-type servo valve 7 switches the hydraulic cylinder 10 between the hydraulic source P and the tank 20 by sliding the spool through the rod 3, balance arm 5, and link 8 by operating the foot pedal 1. Connecting.

5 shows a safety brake device incorporated in the brake device, in which a lever 24 with a pin 23 fixed to its side is fixed to the rotating shaft 9. Reference numeral 25 denotes an interlocking link having an elongated hole 26 in the middle along the rotation trajectory of the tip of the lever 24 and having rods 27, 28 attached to both ends along the direction of the elongated hole, one rod 27 being fixed to the upper rotating body 2 and slidably fitted into a plunger 30 of a single-acting hydraulic cylinder 29 connected to the hydraulic pump, while the other rod 28 is constantly biased toward the hydraulic cylinder 29 via a spring 31 and a spring receiver 32. The pin 23 provided on the lever 24 is movably engaged with the elongated hole 26 provided in the interlocking link 25 by the rotation of the rotating lever 6.

In the above configuration, when the foot pedal 1 is depressed, the rod 3 is pulled to the left in the second figure (in the direction of the arrow), and the pedal force is transmitted to the rod connecting portion a of the balance arm 5. This pedal force is determined by the distance l ₁ , l ₂ between the rod connection part a, lever connection part b, and servo valve connection part c.
(lever ratio) between the rotating lever 6 and the link 8. Therefore, the rotary lever 6 is rotated in the braking direction shown by the arrow in FIG. Brake band 16 is pulled through brake band 15, friction is generated between brake band 16 and brake wheel 17, and the brake is applied. On the other hand, the spool of the servo valve 7 is pushed to the left in the figure via the link 8 by a component of the pedal force transmitted to the servo valve connection part c via the balance arm 5, and the spool of the servo valve 7 is pushed to the left in the figure, and from the hydraulic source P proportional to the amount of movement. Since the pressure of
1, the rotary lever 6 is rotated in the braking direction, and a large force proportional to the component of the pedal force is generated on the brake band 16 via the rod 12, lever 13, rod 14, and lever 15.

Therefore, it is possible to apply a linear brake with a part of the pedal depression force, and also to operate the spool-type servo valve with a part of this pedal depression force, and apply the brake with hydraulic pressure from the hydraulic cylinder 10. Since the braking force can be increased using a large hydraulic pressure proportional to the pedal force while experiencing the pedal force, the pedal force can be smaller than that of a conventional direct brake mechanism. However, the advantage of this mechanism, that is, the operator can directly feel the magnitude of the braking force applied to the hoisting drum with his feet, can be maintained, so that an appropriate braking feeling can be obtained.

In addition, if the hydraulic pump stops operating,
Since pressure oil is not supplied to the hydraulic cylinder 29,
Due to the force of the spring 31, the plunger 30 of the cylinder 29 is pushed in, the interlocking link 25 is moved to the right in the fifth figure, and the pin 23 is pushed through the elongated hole 26 of the interlocking link 25, so the rotation lever 6 is rotated in the braking direction via the pin 23, lever 24, and rotating shaft 9, and the brake is automatically applied.

As described above, the present invention has a simple structure that simply incorporates a balance arm and a servo valve into a conventional mechanical brake actuation mechanism, and can be easily and reliably applied to existing equipment. can be fully achieved.

[Brief explanation of the drawing]

Fig. 1 is a schematic diagram showing a conventional brake device, Fig. 2 is a schematic diagram showing a brake device in an embodiment of the present invention, Fig. 3 is an enlarged view of the main part of Fig. 2, Fig. 4 is a schematic diagram showing the connection state of the servo valve and the hydraulic cylinder in Fig. 3, and Fig. 5 is a schematic diagram showing a safety brake device. 1... Foot pedal, 2... Upper rotating body of the crane, 3, 12, 14... Rod, 4... Spring,
5: Balance arm, 6: Rotating lever, 1
3, 15: Lever; 7: Spool type servo valve; 8, 11: Link; 9: Rotating shaft; 10:
... hydraulic cylinder, 16 ... brake band, 17
...Brake wheel, 18, 19, 21...port of servo valve 7, 20...tank, 22...pipe.

Claims (1)

[Scope of utility model registration request] A balance arm is interposed between a rotary lever and a rod of a link mechanism that can actuate the brake by operating a foot pedal, and a substantially central portion of the balance arm is connected to a rod on the foot pedal side,
A foot-operated brake device, characterized in that one end of the connecting portion is connected to the rotating lever, and the other end is connected to a servo valve for controlling a cylinder that operates the brake.