JPS58148189A - Preventive mechanism of overload of hoist, etc. - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a hoisting device such as a hoist, and more particularly, to a safety braking device for preventing a load from being dropped in the event that a hoisting motor fails, and for hoisting a load exceeding the hoist's rating. This invention relates to an overload prevention mechanism that prevents overload.

! 1. A shows a structural diagram of a conventional hoist. As shown in this figure, the main brake l is inactive, or the H shaft 4 transmits the rotation of the modele to the machine part 6.
If the machine bar breaks, a safety braking device d7 attached to the tip of the machine bart is activated to prevent the load from falling. However, there is no mechanism to prevent hoisting of loads exceeding the rated load.Since around 1980, there has been a movement by law to require all hoist models to be equipped with a mechanical overload prevention mechanism. It is also essential to equip an overload prevention device for expansion. Also, having an overload prevention device is a very effective selling point.

In view of this, it is an object of the present invention to provide a hoist having a simple structure and equipped with both a safety braking device and an overload preventing device by adding an overload prevention function to a conventional safety braking device.

Here, the structure and operation of a conventional safety braking device will be briefly explained with reference to FIGS. 2 to 4. FIG. 2 shows the structure of the safety braking device. Three movable pieces 10 are installed in the notches of a fixed piece 9 fixed to the model pinion 8, and their movements are restricted by leaf springs. A brake shoe 11 is arranged on the outer periphery of the movable piece, and is fixed to an engineering plastic 12 of a machine bar and rotatably attached to a brake cover 13.

Between the brake shoe 11 and the engineering plastic 12, there is a brake wheel 14 whose rotational direction is fixed to the molded pinion 8 and is freely movable in the axial direction, and a brake wheel 15 whose rotational direction is fixed to the engineering plastic 12 and is freely movable in the axial direction. An inclined surface in the circumferential direction is provided on the axial contact surface between the brake shoe 11 and the brake cover 13, where the disc spring 16 is located, and the brake shoe 11 rotates in the direction of the brake wheel 14. The structure is such that thrust is applied towards the

Next, the operation of this device will be explained. As shown in FIG. 3, when the modulus pinion 8 is rotated at a normal speed or lower, the centrifugal force acting on the movable piece 10 is weaker than the force of the leaf spring, and the movable piece 10 rotates while being fixed to the movable piece 10. However, when the main brake l fails, or when the H shaft 4 is broken and the load accelerates and falls, the modal binion 8 rotates at high speed, and the centrifugal force acting on the movable piece increases. When a certain number of rotations is exceeded, the centrifugal force becomes stronger than the force of the leaf spring 17, and the movable piece 10 pops out from the fixed piece 9 and comes into contact with the circumference of the brake shoe 11. This state is shown in FIG. 4-a. As the brake shoe rotates, thrust is applied in the direction of the brake wheel 14. This state is shown in Figure 4-b. The brake wheel 14 includes a brake shoe 11 and a brake disc 1
5, it provides braking force and completely stops the load from falling.

The purpose of the present invention is to provide an overload prevention function to a conventional safety braking device, and to have a simple structure that has both the safety braking function and the overload prevention function, which provides extremely high safety and a major selling point. The purpose of the present invention is to provide a hoisting device such as a hoist.

In order to provide a safety braking device with the above-mentioned overload prevention mechanism, the movable piece is fixed by pressing it in the axial direction from both sides with a cylindrical coil spring, and the reaction force of the spring is used to prevent the moder from overloading. It constitutes a clutch mechanism that cuts off the driving force. At the same time, as described above, when the cylindrical coil panel applies an axial force to the movable piece, K gives the movable piece a rubbing force that overcomes a certain centrifugal force, thereby forming a safety braking device.

An embodiment of the present invention will be described below.

FIG. 5 shows the structure of a safety braking device section of a hoist embodying the present invention. A connecting shaft 19 is provided so as to pass through the center of the molded pinion 18 which engages with the first gear 25. The connecting shaft 19 is connected to the H shaft by a coupling or the like, and is directly connected to the hoisting mode. Connecting shaft 1
9 has a stopper play at the tip with spline 19M)
On the other hand, the molded pinion 18 has a spline 18 which is freely axially movable and rotates in the direction of rotation.
Install the brake wheel 14 that is fixed with M. Inside the engineering plastic 12, as in the conventional case, a brake spring 15 and a counter spring 16 are placed as shown in the figure.
Inside, a fixed piece 21 is attached so as to be fixed to the spline 18a portion of the molded pinion 18, and three movable pieces 22 are provided in the three notches as shown in Figure @6 at both ends of the fixed piece 21. There are two pieces (26, 27ttm) fixed to the molded pinion 18 with a spline 181. Further, a friction material 20a such as a lining is solidly layered on one side of the stopper plate 20, and the stopper plate 20 is configured to be sandwiched between the plates 26. Movable piece 22 and two plays) 26.2
A cylindrical coil spring (push spring) 29 is provided at the point 7. Each cylindrical coil spring 29 has one end fixed to the movable piece 22 and the other end fixed to the pulley L>-) 26 or 27. This state is shown in detail in FIG. 7.

Next, the operation will be explained.

FIG. 8 shows a case where the device operates as an overload prevention device. First, we will explain the case of a load below the rated value. The power of the hoisting mode 2 is transmitted to the stopper plate 20 via the connecting shaft 19. Also, on plates 26 and 27,
A force R3 is applied by the cylindrical coil spring 29 to push it outward. Since the stopper plate 20 is fixed in the axial direction, an axial force R0 is generated between it and the plate 26.
is applied, a frictional force is generated by the friction material 201 fixed to the stopper plate 20, and the rotational force of the stopper plate 20 is transmitted to the plate 26 by the frictional force in the rotational direction. The rotational force transmitted to the machine bar part 6 is transmitted to the molded pinion 18 via the spline 18a, and the rotation is transmitted to the machine bar part 6.
The speed is reduced and transmitted to the drum 3, allowing the load to be raised and lowered.

Next, a case where a load exceeding the rating is applied will be explained.

If a load higher than the rating is applied, the moder binion 1
The load torque acting on 8 will be larger than the rated case. Here, the allowable transmission torque determined by the axial spring force R and the friction coefficient of the friction material 20M is the transmission torque equivalent to the rated load. The spring force etc. are set in advance so that it is equal to . Therefore, even if a transmission torque corresponding to a large load greater than the rated load acts on the modele binion 18, the transmission torque between the friction material 20a and the plate 26 will be larger than the allowable transmission torque, so no rotational force can be transmitted. If the connecting shaft 19 slips, only the connecting shaft 19 is rotated by the moder, and the load cannot be lifted. In this way, it is possible to prevent hoisting of an overload exceeding the rated load.

FIG. 9 shows an explanatory diagram of the case where the brake system functions as a safety braking device. When the rotation speed of the modulus signion 18 is lower than the normal rotation speed, the centrifugal force acting on the movable piece 22 is a radial restraining force on the movable piece 22 formed by the thrust force R, which causes the cylindrical coil spring 29 to sandwich the movable piece 22 from both sides. Since the movable piece 22 is weaker than the fixed piece 21, the movable piece 22 rotates with a portion fixed to the fixed piece 21. However, if the main brake 1 fails, or if the H-shaft 4 is completely damaged and the load accelerates and falls, the modal binion 18 rotates at high speed and the centrifugal force acting on the movable piece 22 increases. When the rotation speed exceeds a certain level, centrifugal force causes spring 2 to
9 becomes stronger than the radial restraining force of the movable piece 22, and the movable piece 22 pops out from the fixed piece 21 and comes into contact with the circumference of the brake shoe 11 (Fig. 9), and the brake shoe rotates. As a result, thrust is applied in the direction of the brake wheel 14. Therefore, the brake wheel 14 is sandwiched between the brake shoe 11 and the brake jib 15 to obtain braking force and completely stop the load from falling.

FIG. 10 shows an explanatory view of load transmission in a hoist embodying the present invention.

According to the present invention, since the conventional safety braking device can be provided with an overload prevention function, it is possible to provide a hoisting method such as a hoist that has a simple structure, is inexpensive, extremely safe, and has a large selling point. can.

[Brief explanation of the drawing]

Figure 41 is a cross-sectional view of a conventional hoist, Figure fIIi2 is a detailed cross-sectional view of its safety control section, Figures 3 and 4 (a)
, FIG. 4(b) is an explanatory diagram of the operation of the second figure, FIG. 5 is a sectional view of the embodiment of the present invention, FIG. Detailed cross-sectional view of the movable piece in the figure! Figure $8,
FIG. 9 is an explanatory diagram of the operation of FIG. 5, and FIG. 10 is a load transmission diagram of the non-inventive embodiment. 1... Main brake, 2... Hoisting mode, 3...
Tram, 4...H shaft, 5...frame, 6...
...Machine part, 7...Safety braking device, 8...Model binion, 9...Fixed piece, 10...Movable piece,
11... Brake shoe, 12... Engineering plastic, 13
...Brake cover, 14...Brake wheel,
15...Brake valve, 16...Disc spring, 17.
...Itabane, 18...Mordle Binion, 19...
・Connection shaft, 19a...Spline, 20...
Stopper plate, 21... Fixed piece, 22... Movable piece, 23... Return spring, 24... Stopper, 25
...1 Dan gear, 26...-plate, 27...plate, 29...cylindrical coil spring, 2nd country, 3rd entry! -5th eye 12th 6th a child 7th figure

Claims (1)

[Claims] 1. A fixed piece weird onto the brake mechanism, a plurality of movable pieces that rotate together with the fixed piece and pop out in the radial direction due to centrifugal force;
A brake shoe installed on the outer periphery of the movable piece is provided with rotational force by the movable piece, and the rotation gives a thrust to a brake wheel separately provided on the brake shaft, thereby generating a braking force. The braking device is characterized in that both ends of the movable piece are sandwiched between two coil springs, and at the same time, a friction material is provided in the direction in which the pushing force of the spring acts.A plate is attached to the input shaft. Overload prevention mechanism for hoists, etc.