JPS6128695Y2 - - Google Patents

Description

[Detailed description of the invention] The present invention relates to an expansion jack for attaching a brake shoe, and is intended to prevent this member from falling off the brake shoe and to prevent the tightening force from decreasing due to temperature changes, etc. With the goal.

When gluing the lining 2 to the brake shoes 1 of an internal expansion type brake and drying it in a drying oven, a pair of brake shoes 1 are placed inside the outer ring band 3 as shown in Fig. 1, and both brake shoes are You 1
An expansion jack 5 is interposed between the ribs 4 of the lining 2 and the outer ring band 3.
The pair of brake shoes 1 are expanded radially outward so as to come into pressure contact with the brake shoes 1, and placed in a drying oven in the expanded state. However, in the conventional expansion jack 5, a rotatable jack main body 6 is provided with a threaded shaft 7 that is screwed onto the jack main body 6, and a rotatable shaft 8 that is rotatable. 9 and 10 are formed, respectively, and the respective engaging grooves 9 and 10 are made to engage with the ribs 4 of each brake shoe 1, so there is only one contact point with respect to the brake shoe 1, which may cause imbalance. Therefore, there was a risk that the expansion jack 5 would come off from the brake shoe 1 during expansion, so it was necessary to be careful when expanding. In addition, in the past, since the screws were simply tightened, they loosened over time and the expansion force decreased, and if the outer ring band 3 was stretched due to the heat effect when placed in the drying oven. However, there was also the drawback that the lining 2 could not be reliably adhesively fixed to the brake shoe 1 because it could not absorb the elongation.

The present invention provides a new expansion jack that solves these conventional problems.The feature is that a pair of brake shoes arranged in the outer ring band are connected to the lining of the outer ring. In an expansion jack for attaching a brake shoe that expands radially outward so as to come into pressure contact with the band, a threaded shaft is screwed into the jack body, and a support shaft is rotatably fitted inside the jack, and the outer end of each shaft is Attach the central part of the member whose longitudinal ends are in contact with the inner surface of the brake shoe, and install a spring that biases the member outward between at least one of the members and the spring receiving member on the inside thereof. It is at the point of intervention.

Hereinafter, the present invention will be described in detail with reference to the illustrated embodiments. In FIGS. 2 to 7, reference numeral 10 denotes a rotatable cylindrical jack main body with a hexagonal outer circumferential surface; There is a support shaft 11
A cylindrical portion 12 is fitted therein so as to be rotatable and slidable in the axial direction, and a screw shaft 14 is screwed into the closing screw hole 13 so as to be movable in the axial direction. and screw shaft 1
The inner end side of 4 is loosely fitted into the cylindrical portion 12 of the support shaft 11. At the outer ends of the support shaft 11 and the screw shaft 14, members 15 and 16, spring bearing members 17 and 18, and disc springs 19 and 20 are provided, respectively. The members 15 and 16 have a U-shaped cross section, and have contact portions 15 at both ends in the longitudinal direction that contact the inner surface of the brake shoe 1.
a, 16a are each formed into a curved surface, and each of these contact members 15, 16 is located at the center of the longitudinal direction, and
1 and 14 so as to be slidable in the axial direction, and are prevented from coming off by set screws 21 and 22. The spring bearing members 17, 18 also have a U-shaped cross section, and are inserted and supported by the respective shafts 11, 14 at the center in the longitudinal direction.
Between the members 15, 16, there are strip-shaped contact plates 23, 24 and a plurality of disc springs 19, 20.
is interposed so as to bias it outward. The spring receiving member 17 is engaged with the stepped portion 11a of the support shaft 11 via a contact plate 25 having a spherical portion 25a, and the spherical portion 25a is in surface contact with the inner periphery of the opening of the jack body 10 over the entire circumference. It is set up like this. On the other hand, the spring receiving member 18 is engaged with the stepped portion 14a of the screw shaft 14 via a band-shaped receiving plate 26. Note that notches 15b and 16b are formed at both ends of each of the members 15 and 16, respectively, so as to avoid interference with the rib 4 of each brake shoe 1.

The expansion jack with the above configuration is used as follows. First, a pair of brake shoes 1 are placed inside the outer ring band 3, and then an expansion jack 5 is set between the pair of brake shoes 1. In this case, the contact members 15 and 16 have contact portions 15a and 16a at both ends in contact with the inner surface of the brake shoe 1, respectively. Then, when the claws of a separately provided automatic expansion machine are engaged with the inner surfaces of the receiving plates 25 and 26 on both sides of the jack main body 10 and the automatic expansion machine is operated in this state, the jack main body 10 and the support shaft 11 is slidable in the axial direction, each receiving plate 25, 26 is attached by a claw.
The members 15, 16 are expanded outward through the .
Therefore, when the jack main body 10 is rotated next, the jack main body 10 moves in the direction of extension from the screw shaft 14.
moves, and its open end becomes the spherical part 25a of the receiving plate 25.
, so by turning and tightening the jack body 10 until the predetermined torque is reached, each disc spring 1
9 and 20 are compressed to urge the members 15 and 16 outward and press the lining 2 against the outer ring band 3. Even after tightening, the disc springs 19 and 20 are in a compressed state and their repulsive force is maintained, so even if vibrations or the like are applied from the outside, the jack body 10 and screw shaft 14
It is difficult for the disc spring 1 to loosen even when the outer ring band 3 is stretched due to thermal action.
9 and 20 can absorb the expansion and maintain the tightened state at a predetermined torque. One receiving plate 2
A spherical part 25a is provided on the jack body 1.
0, the pair of contact members 15 and 16 do not need to be in a completely parallel state.

In the embodiment, the support shaft 11 is connected to the jack body 1.
0, but the support shaft 1
1 is formed with a screw in the opposite direction to the screw shaft 14, and this is screwed into the jack main body 10, so that the jack main body 1
0, the support shaft 11, and the threaded rod 14 may constitute the turnbuckle.

It is also possible to provide elasticity to the members 15, 16 themselves. Furthermore, one of the disc springs 19 and 20 can be omitted. The spring may be a coil spring or the like other than a disc spring.

The present invention includes a pair of contact members, and both ends of each contact member contact the inner surface of the brake shoe, so there are four contact points compared to the conventional method, and the balance during expansion is improved. It is less likely to go awry, there is less risk of the member falling off the brake shoe, and it is easier to handle. In addition, since a spring that biases outward is interposed between at least one of the shafts and this member, there is little loosening of the threaded part due to vibration, etc., and even when the outer ring band is stretched due to heat. It is possible to absorb this amount of torque, maintain a predetermined torque expansion state at all times, and reliably bond the lining to the brake shoe.

[Brief explanation of the drawing]

Fig. 1 is a front sectional view showing a conventional example, Fig. 2 is a front view showing an embodiment of the present invention, Fig. 3 is a front view of the main part, Fig. 4 is a plan view of the main part, 5 is a side view of the same essential parts, FIG. 6 is a cross-sectional view taken from FIG. 3, and FIG. 7 is a cross-sectional view taken from FIG. 6. 1... Brake shoe, 2... Lining, 3
...Outer ring band, 5...Expansion jack, 10...
Jack main body, 11... Support shaft, 14... Screw shaft, 15, 16... This member, 17, 18... Spring receiving member, 19, 20... Disc spring.

Claims (1)

[Scope of utility model registration request] A brake shoe attachment expansion jack expands a pair of brake shoes disposed inside an outer ring band radially outward so that its lining comes into pressure contact with the outer ring band. A support shaft is rotatably fitted inside the shaft, and a central part of the member whose longitudinal ends contact the inner surface of the brake shoe is attached to the outer end of each shaft, and at least one of the member and the spring inside thereof are attached. An expansion jack for attaching a brake shoe, characterized in that a spring is interposed between the support member and the support member to urge the member outward.