JPS6114371B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a mechanical brake actuation mechanism in an internally expanding brake device having a pair of brake shoes, and particularly to a mechanical brake operating mechanism for an internally expanding brake device having a pair of brake shoes. The present invention also provides an operating mechanism that constitutes a mechanical dual-to-leading brake that serves as a leading brake. Conventionally, as an operating mechanism for a mechanical dual-toe leading brake, one such as that disclosed in Japanese Patent Publication No. 46-25643 has been known, but the present invention provides an internal expansion type brake device having a pair of brake shoes, one of which One end of a first lever is pivotally connected to one end of a brake shoe, and one end of a second lever is pivotally connected to one end of another brake shoe that is diagonally separated from one end of the one brake shoe. A strut is interposed between the intermediate portion of the first lever and the other end of the other brake shoe, and a strut is also interposed between the intermediate portion of the second lever and the other end of one brake shoe. Interpose the middle part of the operating lever to the first
The other end of the lever is pivotally connected to the other end of the lever, and the other end of the second lever is connected to one end by a connecting means, and the other end of the operating lever on the first lever pivot point side of the operating lever is directed toward the second lever. It is characterized by a brake operating mechanism that operates the pull brake.

Embodiments of the present invention will be described below based on the drawings.

In the drawing, 1A and 1B are a pair of brake shoes, each end of which is connected to a pair of wheel cylinders 3A and 3B fixed to a support plate 2. The wheel cylinders 3A, 3B each have pistons 4, 5 on both sides that can be freely moved in and out, one piston 5 being rotatable by an adjustment wheel 6 and having an adjustment rod 7 screwed therein so that it can be moved in and out. In contrast to the upper and lower wheel cylinders 3A and 3B, the upper end of the right brake shoe 1A is the upper wheel cylinder 3.
The lower end of the left brake shoe 1B engages with the longitudinal groove at the tip of the adjustment rod 7 of the lower wheel cylinder 3B, and the upper end of the left brake shoe 1B engages with the longitudinal groove at the tip of the adjustment rod 7 of the upper wheel cylinder 3A. The lower end engages with the vertical groove at the tip of the piston 4 of the lower wheel cylinder 3B, and springs 8, 8 are tensioned vertically between the two brake shoes 1A and 1B and biased inward. , both wheel cylinders 3
It is pressed against A and 3B. A lining 9 is fixed to the outer circumferential surface of the brake shoes 1A, 1B, and a brake drum (not shown) is disposed outside the lining 9, and the brake is applied by the expansion operation of the wheel cylinders 3A, 3B. Show 1
A and 1B move outward and the lining 9 comes into pressure contact with the inner surface of the brake drum, providing a friction braking effect. In addition, 10 is a clip spring, 11 is a pin, and brake shoes 1A, 1
B is stopped at the reference position, and wear of the lining 9 is compensated for by adjusting the protrusion amount of the adjustment rod 7 using the adjustment wheel 6.

To explain the mechanical brake operating mechanism of the present invention installed in parallel with the conventional hydraulic brake device described above, a first lever 1 is installed near the upper end of the right brake shoe 1A.
The upper end of the second lever 14 is pivotally connected with a pin 13, and the lower end of the second lever 14 is pivotally connected with a pin 15 near the lower end of the left brake shoe 1B. Further, a lateral upper strut 16 is interposed between the upper intermediate portion of the first lever 12 and the upper inner side of the left brake shoe 1B, while a lower intermediate strut 16 is interposed between the lower intermediate portion of the second lever 14 and the upper inner side of the left brake shoe 1B. Similarly, a horizontal lower strut 17 is interposed between the inner lower part of 1A. Recesses are provided at both ends of both struts 16, 17, and these recesses engage with notches provided in the first lever 12, second lever 14, and both brake shoes 1A, 1B.

On the other hand, the middle part of an operating lever 18 is pivotally connected to the lower end of the first lever 12 with a pin 19, and the upper end of this operating lever 18 and the upper end of the second lever 14 are connected by a connecting means 20 such as a cable or a link. connect,
An operating means (not shown) is provided at the lower end of the operating lever 18.
The brake lever is connected to the brake lever 14 and pulled in the direction of the second lever 14 to operate the brake device.

Next, the operation of the mechanical brake operating mechanism is as follows:
From the non-operating state as shown in Fig. 1, the operating lever 1 is
When the lower end of the lever 8 is pulled in the direction of the second lever 14, the first lever 12 rotates inward about the pin 13 at the upper end, pushing the upper strut 16 to the left and releasing the upper part of the left brake shoe 1B. At the same time, the first lever 12 rotates about the engagement portion with the upper strut 16 as a fulcrum, and moves the upper part of the right brake shoe 1A outward via the pin 13 at the upper end. . Further, the operating lever 18 rotates around a pin 19 in the intermediate portion, and connects the connecting means 2.
0, pull the upper end of the second lever 14 through the
Rotation of the lever 14 about the pin 15 pushes the lower strut 17 to the right, moving the lower part of the right brake shoe 1A outward, and rotation about the engagement part with the lower strut 17 as a fulcrum. The left brake shoe 1B is connected via the pin 15 at the lower end.
Move the lower part of both brake shoes 1 outward.
Braking force is obtained by pressing the linings 9 of A and 1B evenly against the brake drum, resulting in a braking state as shown in FIG.

Therefore, according to the present invention as described above, in order to press both ends of the pair of brake shoes to bring them into pressure contact with the brake drum, both brake shoes are always connected to the leading shaft regardless of the rotating direction of the brake drum. As a result, a dual-to-leading type brake with excellent braking characteristics can be constructed. In addition, since each lever is supported by a brake shoe and is not located on a fixed part, even if any part of the brake shoe contacts the brake drum first, other parts will also contact the brake drum in turn, resulting in the pressing force Therefore, each part of both brake shoes comes into pressure contact with the brake drum uniformly, and this combined with the ability to configure the dual-two leading brake described above, provides an extremely excellent braking effect in the internal expansion type brake system. It is capable of performing mechanical brake operation. Further, the upper and lower inward expansions of the brake shoe are independent, such that the first lever is responsible for displacement of the upper end of the brake shoe, and the operation lever is responsible for displacement of the lower end of the brake shoe. Therefore, for example, if the distance between the brake shoe and the drum is narrow at the upper end of the brake shoe and wide at the lower end of the brake shoe, the upper end of the brake shoe is pressed by the brake drum and the first Even if the lever cannot be moved any further,
The operating lever further rotates clockwise in the drawing to press the lower end of the brake shoe against the brake drum. As described above, according to the mechanical brake actuation mechanism of the present invention, the brake shoe is sufficiently expanded in all directions, and a sufficient braking effect can always be obtained.

Further, the mechanical brake actuation mechanism of the present invention has a small number of parts, is easy to assemble, and operates efficiently and safely. Further, it can be easily installed in parallel with a hydraulic brake device, and can be used for parking brakes in automobiles and mechanical brake devices for various other devices, so its utility value is high.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention, and FIG. 1 is a front view of a brake device equipped with the mechanism of the present invention with a brake drum removed, and FIG. 2 is a front view of the brake device in an operating state. 1A, 1B...Brake shoe, 12...1st
Lever, 13, 15, 19... Pin, 14... Second lever, 16, 17... Strut, 18...
Operation lever, 20...connection means.

Claims (1)

[Claims] 1. In an internal expansion type brake device having a pair of brake shoes, one end of the first lever is pivotally connected to one end of one brake shoe, and is separated diagonally from the other end of the first brake shoe. One end of the second lever is pivotally connected to one end of the other brake shoe, and a strut is interposed between the intermediate portion of the first lever and the other end of the other brake shoe, and the intermediate portion of the second lever is A strut is also interposed between the part and the other end of one of the brake shoes, the intermediate part of the operating lever is pivotally connected to the other end of the first lever, and the other end of the second lever is operated by the connecting means. A mechanical brake actuation mechanism for a braking device, characterized in that it is connected to one end of a lever on the side of a first lever pivot point, and operates the brake by pulling the other end of the operating lever in the direction of the second lever.