JPH0126898Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a screw brake that is widely used as a brake mechanism for hoisting machines, for example.

FIG. 1 is a sectional view showing a conventional screw brake, and FIG. 2 is a sectional view taken along the line -- in FIG. In the figure, 1 is a casing, 2 is an output rotating shaft rotatably supported by the casing 1, 3 is an input rotating plate screwed onto the shaft 2, and 4 is a friction plate fixed to the shaft 2 with a pin 5. A plate 6 is a friction member disposed between the input rotary plate 3 and the friction plate 4, and is composed of a ratchet plate 7 with linings 8 pasted on both sides. The friction member 6 is rotatably supported by the boss 3a of the input rotary plate. The input rotary plate 3 is composed of a gear having teeth 3b on its outer peripheral surface, and is connected to a drive source (not shown) such as a motor via an input pinion shaft 9. The ratchet plate 7 has a second
The pawl 10 is engaged in the manner shown in the figure, and the pawl 10 is constantly pressed against the ratchet plate 7 by a spring or the like (not shown).

A case where the operation of the screw brake described above is used as a brake mechanism for a hoist will be explained.

During winding, the input pinion shaft 9 rotates in the winding direction (arrow A direction), and this rotation is transmitted to the input rotary plate 3. Then, input rotary plate 3
In order for the input rotary plate 3 to move toward the friction plate 4 when the input rotary plate rotates in the winding direction (direction of arrow B) with respect to the output rotating shaft 2, the internal thread 3 of the input rotary plate is
c and the male screw 2a of the output rotating shaft are screwed together, so the input rotating plate 3 moves toward the friction plate 4 and presses the friction member 6 against the friction plate 4. Therefore, the friction member 6 is sandwiched between the input rotary plate 3 and the friction plate 4, and these three rotate as one.
The rotation is transmitted to the output rotating shaft 2 via the pin 5, and winding is performed. In this case, nail 1
0 is in a free state and is not caught on the ratchet plate 7.

Next, a description will be given of when the engine is stopped. When the drive source is stopped from the hoisting state and the rotational force of the input pinion shaft 9 disappears, the output rotating shaft 2 attempts to rotate in the hoisting direction opposite to arrow B due to an external load, such as the weight of the hoisted object. . but,
In this state, the friction member 6 is tightened by the input rotary plate 3 and the friction plate 4 as in the case of winding up, and the pawl 10 is caught on the ratchet plate 7 in the lowering direction of the output rotary shaft, so that the output The rotating shaft 2 does not rotate in the lowering direction and maintains a stopped state.

When shifting from the stopped state to the lowering state, the input pinion shaft rotates in the lowering direction opposite to the arrow A, and the input rotary plate 3 moves in a direction away from the friction plate 4. Then, although the ratchet plate 7 still does not rotate in the lowering direction (the direction opposite to arrow B) due to the pawl 10, the input rotary plate 3, friction member 6, and friction plate 4 are released from the pressed state, and the output is released. Since the rotating shaft 2 and the friction member 6 are in a free state, the output rotating shaft 2 is rotated in the lowering direction by an external load (load), and lowering is performed. In this case, when the lowering rotational speed of the output rotating shaft 2 becomes faster than the lowering rotational speed of the input rotating plate 3 by the input pinion shaft, the relative rotation of the input rotating plate 3 with respect to the output rotating shaft 2 becomes a winding rotation, and the input rotation The plate 3 moves in the direction of the friction plate 4, a brake is applied by the frictional force of the friction member 6, and the lowering rotational speed of the output rotating shaft 2 is reduced. When the speed decreases and the relative rotation of the input rotary plate 3 with respect to the output rotary shaft 2 becomes a downward rotation, the input rotary plate 3 moves away from the friction plate 4 again, and the brake is released. While repeating this operation, the output rotating shaft 2 is lowered and rotated at a rotational speed that matches that of the input pinion shaft 9, and lowering is performed at a constant speed.

However, the conventional screw brake described above does not have a mechanism for restricting the relative rotation between the input rotary plate 3 and the friction plate 4. Therefore, when the amount of rotation of the input rotating plate 3 in the lowering direction relative to the output rotating shaft 2 increases beyond a predetermined amount, for example when the drive source switch is switched to lowering during the hoisting operation, the input rotating plate 3 It moves to the left until it comes into contact with the left end surface 1a, and the female screw 3c of the input rotary plate and the male screw 2a of the output rotary shaft become wedged, and there is a possibility that a situation will occur in which both 2 and 3 become unable to separate. In this state, the friction member 6 is opened and the output rotating shaft 2 becomes free, which is dangerous because the brake will not work at all. The above-mentioned phenomenon of biting of the threaded portion also occurs when the hoist is lowered and rotated under no load. In this case, the output rotary shaft 2 itself is stationary because no rotational force is generated by the load, and only the input rotary plate 3 rotates in the lowering direction.

In view of the above-mentioned circumstances, the purpose of the present invention is to provide a screw brake that eliminates the above-mentioned danger by regulating the amount of relative rotation between the input rotary plate and the friction plate and eliminating the possibility of the thread becoming wedged. It's about doing.

Hereinafter, the present invention will be described in detail with reference to embodiments shown in the drawings.

3 is a cross-sectional conceptual diagram (--line sectional conceptual diagram in FIG. 4) showing an embodiment of the screw brake according to the present invention, and FIG. 4 is a sectional conceptual diagram taken along the-- line in FIG. 3. The basic configuration and operation of this embodiment are the same as those of the conventional example shown in FIGS. 1 and 2, so the same components are designated by the same numbers and their explanations will be omitted.

As shown in the figure, the screw brake according to the present invention includes an output rotating shaft 2, an input rotating plate 3 screwed onto the shaft 2, a friction plate 4 fixed to the shaft 2, and an input rotating plate 3. In a screw brake comprising a friction member 6 disposed between the input rotary plate 3 and the friction plate 4, stoppers 12, which are to be engaged with each other, are provided on opposing surfaces 3d and 4d of the input rotary plate 3 and the friction plate 4, respectively. 13
are protrudingly provided at a predetermined angle apart in the circumferential direction.

In this embodiment, both stoppers 12 and 13 are formed as semicircular rings, and the stopper 12 is fitted into a recess 3e formed on the opposing surface 3d of the input rotary plate and fixed with a bolt 14, and the stopper 13 is attached to a friction plate. The end faces 12 of both stoppers are fitted into the recesses 4e formed on the opposing faces 4d and fixed with bolts 15.
a, 13a are arranged to face each other, and both end surfaces 1
A gap of a predetermined angle θ is provided between 2a and 13a. Therefore, relative rotation between the input rotary plate 3 and the friction plate 4 is allowed only by a predetermined angle 2θ, and rotation beyond this angle is not possible. Therefore, there is no possibility that the input rotary plate 3 will move to the left end surface 1a of the casing and the threaded portion will become stuck.

Reference numeral 16 denotes a spring inserted into recesses 12b and 13b formed in the opposing surfaces 12a and 13a of both stoppers;
3, the input rotary plate 3 is urged in the winding rotation direction (arrow B direction) with respect to the output rotary shaft 2. Therefore, the spring 16 can constantly generate an initial braking force and provide braking performance when no load is loaded.

In addition, the semicircular ring 12, 1 serving as the stopper is
By forming 3 from a bearing material, the semicircular rings 12 and 13 also serve as bearings for the friction member 6. However, the bearing of the friction member 6 may be provided by the boss of the input rotary plate 3 as in the conventional example, or furthermore, the friction plate 4 may be provided with a boss portion to serve as a bearing. Further, the ratchet plate 7 and the lining 8 forming the friction member may be formed by joining them together, or may be formed separately from each other.

In this embodiment, semicircular rings 12 and 13 are used as stoppers, and there are two gaps θ between them.
By providing this, relative rotation between the two is regulated in both rotational directions. However, since the present invention prevents the threaded portion from becoming stuck due to biting, at least the input rotary plate 3 is
Since it is only necessary to restrict the relative rotation in the direction away from the friction plate 4 by a predetermined amount, the configuration of the stoppers 12 and 13 can be changed in various ways within the range where this restriction is possible. Further, both stoppers may be formed integrally with the input rotating plate and the friction plate, respectively.

[Brief explanation of the drawing]

Fig. 1 is a sectional view showing a conventional screw brake, Fig. 2 is a sectional view taken along the line - - in Fig. 1, Fig. 3 is a conceptual sectional view showing an embodiment of the screw brake according to the present invention, and Fig. 4 is FIG. 3 is a cross-sectional conceptual diagram taken along the line - in FIG. 3; 2... Output rotating shaft, 3... Input rotating plate, 3...
Friction plates, 3d, 4d... opposing surfaces of the input rotating plate and friction plates, 6... friction members, 12, 13... stoppers.

Claims (1)

[Scope of utility model registration request] A screw brake comprising an output rotating shaft, an input rotating plate screwed onto the shaft, a friction plate fixed to the shaft, and a friction member disposed between the input rotating plate and the friction plate. The screw brake according to the invention, wherein stoppers to be engaged with each other are provided protruding from each of the facing surfaces of the input rotary plate and the friction plate at a predetermined angle apart in the circumferential direction.