JPS5842390Y2 - Overload prevention device - Google Patents

Description

[Detailed Description of the Invention] This invention relates to a device for preventing overload hoisting of an electric chain hoist.

It is generally known that when hoisting a load on a hoisted rock, fluctuations in the load cause a wave-like phenomenon centered around the rated load level.

In other words, even if the rated load is lifted due to changes in the load at the moment when hoisting is stopped or when hoisting is stopped, approximately 1.3
The instantaneous overload phenomenon of ~1.6 times is repeated.

The same phenomenon occurs at the moment of hoisting up from a suspended state, or even when hoisting is stopped.

Therefore, the commonly used overload detection switch is installed in series with the hoisting relay for driving the magnetic switch installed in the three-phase power supply circuit of the hoisting motor, so it is possible to hoist at the rated load. Even if this is done, the load repeats and momentarily exceeds the set overload level for switching, which frequently causes the overload detection switch to operate in a chattering manner, which prevents normal hoisting. was there.

The purpose of this invention is to deal with such chattering phenomenon,
An object of the present invention is to provide an overload prevention device that operates only when there is a true overload condition.

Embodiments of this invention will be described below with reference to the accompanying drawings.

As shown, the overload prevention device A includes a pair of plates 1,
2, a support shaft 3 installed between the plates 1 and 2, a tilting body 4 whose end portion is rotatably supported on the support shaft 3, and an elastic member 5 provided to push up the end of the tilting body 4. and,
An engaging member 6 such as a hook whose lower end is connected to the center of the tilting body 4; an engaging member 7 such as a hook whose upper end is connected to the lower edges of the plates 1 and 2; A sector gear 8, a small diameter gear 9 supported on plates 1 and 2 so as to mesh with this sector gear 8, a large diameter gear 10 provided to rotate coaxially with this small diameter gear 9, and this large diameter gear 9. A small diameter gear 11 is supported on plates 1 and 2 so as to mesh with the gear 10, a rook 13 is provided on the shaft 12 of the small diameter gear 11 so as to rotate freely, and the rook 13 rotates together with the shaft 12 on both sides of the rook 13. and discs 14, 14' provided so as to be able to slide in the axial direction, and these discs 14, 14'.
and the friction member 15 interposed between the rook 13 and the disc 14.
A spring 16 is provided on the outside of the plate 1 to press the rook 13 and the disk 14' toward the small diameter gear 11, a claw 17 is provided to prevent the water wheel from rotating 130 times until the friction member 15 slips, and the plate 1 and a switch 18 supported so as to be activated by the tilting body 4 when the tip of the tilting body 4 rotates in the upward direction.

Further, a nut 19 for compressing the disc-shaped spring 16 is screwed into the shaft 12, and the nut 19 is adjusted so that the friction member 15 slips when a predetermined rated load is reached.

A seat 20 is provided on the lower surface of the end of the tilting body 4 and the plate 1.degree. 2, and an elastic member 5 made of a spring is interposed between the seats 20.

In the figure, 21 is a pin that connects the bracket 22 of the engagement member 6 and the tilting body 4, and 23 is a bracket to which the engagement member 7 provided on the plates 1 and 2 is attached.

The overload prevention device according to this invention is different from the above-described structure, and is used to prevent overload by engaging the cheno and the engaging members 6 and 7 in the middle of the chino (not shown) of the lifting machine. Device A is interposed (sometimes it is inserted into the winding iso).

Further, the switch 18 and the motor of the lifting machine are electrically connected so that when the switch 18 is turned on, the operation of the motor is stopped, but instead of the connection of the motor, the motor is connected so as to issue an alarm. You may.

Next, to explain the action during rolling up, as the plates 1 and 2 are rolled up, the tilting body 4 is pulled in a direction in which the plates 1 and 2 are lowered and their tips are raised.

At this time, the rook 13 is clamped by the friction member 15 of the discs 14, 14' by the spring 16, and the rook 13 is clamped by the claw 17.
3 is stopped from rotating, the tip of the tilting body 4 is rotated by the large diameter gear 10 that meshes with the small diameter gear 11 that is restrained from rotating, and the sector gear 8 that meshes with the coaxial small diameter gear 9. prevent it from rising.

Therefore, the switch 18 does not operate.

However, if the hoisting load exceeds the rated load (exceeds the clamping force of the rook 13 by the spring 16), the rook 13 is lifted together with the small diameter gear 11 by the sector gear 8 through the large diameter gear 10 coaxial with the small diameter gear 9. The rook 13 is rotated by slipping on the clamping friction member 15.

Therefore, the tilting body 4 is rotated counterclockwise in FIG. 1, and the switch 18 is turned on by the tilting body 4, thereby stopping the operation of the lifting machine.

At this time, since the end of the tilting body 4 descends, the elastic member 5
is compressed.

When the warped article exceeding the rated cart is removed, the lifting of the tip of the tilting body 4 is released and the tilting body 4 is rotated back by the elastic member 5.

For this reason, from sector gear 8 to small diameter gear 9 and large diameter gear 1.
0. Since the shaft 12 is reversed counterclockwise in FIG. 1 through the small diameter gear 11, the pawl 17 escapes from the pawl of the rook 13, reversing the rook 13, and returning the tilting body 4 to its original state. .

As described above, according to the overload prevention device according to the present invention, when hoisting up to the rated load, the rook is clamped by the friction member to prevent rotation of the rook.

Therefore, the lifting machine can be hoisted up while preventing the tilting body from rotating.

However, when the hoisting load exceeds the rated load, the rook 13 slips and rotates with respect to the friction member 15 from the sector gear 8 through the gear group.

Therefore, since the tilting body 4 rotates to actuate the switch, it is possible to stop the operation of the lifting machine and prevent an accident from occurring.

If you remove an item that exceeds the rated load above,
The tilting body 4 is rotated back by the elastic member 5.

At this time, the rook 13 is reversed via the sector gear 8 and the gear group, and the pawl 17 engages with the rook 13 when the reverse rotation is stopped, so that the rook can be set automatically.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional front view of the device according to this invention, and FIG. 2 is a lateral plan view of the same. A... Overload prevention device, 1... Plate, 2... Plate, 3... Support shaft, 4
...Tilt body, 5...Elastic member, 6...
...Engagement member, 7...Engagement member, 8...
...Sector gear, 9...Small diameter gear, 10.
...Large diameter gear, 11...Small diameter gear, 12
...shaft, 13...waterwheel, 14,14'
...Disc, 15...Friction member, 16.
...Spring, 17...Claw, 18...
·switch.

Claims (1)

[Scope of utility model registration request] a plate, a horizontal tilting body whose distal end portion is pivotally supported on the plate via a support shaft, and a retaining member such as a hook provided at the center of the tilting body and on the lower edge side of the plate, respectively;
A water wheel is engaged with a sector gear provided at the tip of the tilting body so as to rotate together through a gear group, and is supported on a plate so as to rotate freely through a shaft, and a water wheel is supported on both sides of the water wheel. A disc provided to rotate with the shaft and slide in the axial direction, a friction member interposed between this disc and the water wheel, an elastic member provided to push up the end of the tilting body, and a When an upward force is applied to the tip, the pawl is pivoted on a plate and engages with the water wheel to prevent rotation, and when the overload exceeds the set value, slipping occurs between the disc and the friction member. A spring is installed to press the disc against the water wheel, and a switch is installed to operate when the tilting body comes into contact with the tip of the tilting body. An overload prevention device designed to stop the operation.