JPS6320710Y2 - - Google Patents

Description

[Detailed Description of the Invention] This invention relates to a crane with tongues equipped with a landing control device suitable for use as a crane for transporting long materials such as slabs or blooms.

Normally, when a crane is used to transport long materials such as slabs or blooms, a crane equipped with two-point suspended electric tongs is often used.

The problem here is that electric tongs do not have legs or similar support members to support the weight of the tongs themselves when gripping and releasing conveyed objects such as slabs and blooms. If the place where the conveyed object is lifted or landed is inclined in the longitudinal direction of the conveyed object, or if the conveyed object itself has defects such as warping or bent ends, both ends of the conveyed object may become distorted when it lands on the floor. They do not land at the same time, and the rope on the side that landed first becomes slack. Therefore, as soon as the electric tongs are opened, the tongs cause a free fall phenomenon corresponding to the slack in the rope, giving a shock to the main body of the hoisting device, which may lead to an accident.

The present invention has been made with the aim of eliminating such conventional problems, and an embodiment thereof will now be described based on the drawings.

The hoisting device applied to this invention consists of a movable trolley 2 supported on a movable crane girder 1, and two driving units connected to the trolley 2 via a detachable clutch 3. motor 4 and
Two hoisting drums 6, 6 arranged on the same axis are interlocked with the drive motor 4 via a deceleration mechanism 5.
The sheave 8 is attached at both ends to each hoisting drum 6, 6 and is supported on an electric tong 11, the sheave 9 is supported on a trolley, and the sheave 10 is again supported on an electric tong 11. electric tongs 11 suspended from the hanging ends of two ropes 7, 7;
A sheave 9 that guides and supports the middle of each hoisting rope 7 is vertically movably supported by a pair of brackets 12 fixed on the trolley 2.
The drive motor 4 for the stand can be driven integrally or separately by engaging and releasing the clutch 3.

The sheave 9 that guides the middle of the hanging end of the hoisting rope 7 has load cells 13, 13' installed in the bracket 12 fixed on the trolley 2;
Spring receivers 14, 1 are placed on the load cells 13, 13'.
Spring 15 inserted through 4' and spring receiver 1
It is elastically supported by a sheave support bearing 16 mounted on the sheave support bearing 4'.

The spring receivers 14, 14' are not rotatable due to the U-shaped notches formed on their sides and the guides 12' protruding parallel to the vertical axis of the bracket 12, but the guides 12 A detection device 17 is provided at the end of each drum shaft to detect the length of the rope when the clutch 3 is disengaged.

The load cell 13 mounted on the trolley 2 is
The load applied to the sheave 9 from each hoisting rope 7 is detected, and based on the detected value and two preset values (first set load and second set load),
A signal is sent to a drive control mechanism (not shown) electrically connected to the load cell 13, and the sequence is electrically sequenced by known technical means to automatically perform operations such as stopping the winding and lowering of the drums 6, 6. is assembled.

The present invention has the above-mentioned configuration, and the operation will now be described in the case where the electric tongs 11 cause a conveyed object held in a horizontal state to land on an inclined floor.

First, both drums 6, 6 are driven by simultaneous driving of the drive motors 4, 4 with the clutch 3 engaged, and lowering is started. Following this lowering,
The load on the rope 7 on the side where the conveyed object S landed first is reduced. Then, when the load detected by the load cell 13, 13' on the side that landed first reaches the first set load, a lowering stop signal is issued to the drive control mechanism, the rotation of the drive motor 4 is stopped, and the lowering operation is performed. stop.

However, since the detected load of the load cells 13, 13' on the non-landing side is higher than the first set load, the clutch 3 is disengaged and only the drum 6 on the non-landing side is lowered, and the load cells 13, 13' on the non-landing side are lowered. When the load ' reaches the first set load, the drum on that side also stops lowering.

Afterwards, engage clutch 3 again and wind up both drums a little. And load cell 13,1
The hoisting is stopped when the detected value 3' becomes equal to the second set load suitable for opening the electric tongs, and the claw of the electric tongs is then opened to release the conveyed object S. At this time, since the two ropes 7, 7 that suspend the electric tongs 11 are both under tension, the electric tongs will not fall.

Further, for example, if the first set load is set to a set load smaller than 1/2 of the weight of the electric tongs 11 and the second set load is set to a set load approximately equal to 1/2 of the weight of the electric tongs 11, No load impact is applied to the crane girder side.

After these operations are completed, one of the drums is driven to wind up a predetermined amount by a drive control mechanism connected to the detection device 17 for detecting the rope payout length, and the horizontality of the electric tongs is corrected. Prepare for the next lift.

Since the present invention has the above-described structure and function, when releasing the conveyed object from the electric tongs, the hoisting rope is kept taut and the claw is released, so there is no reaction to the electric tongs. , its protection is perfect.

Further, since a device for detecting the length of the rope being fed out is provided, the tongs can be immediately returned to their original state even after the conveyed object is released, which is also suitable in terms of work safety and efficiency.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention, and FIG. 1 is a schematic front view, FIG. 2 is a side view, and FIG. 3 is a plan view.
FIG. 4 is a detailed view of section A in FIG. 1, and FIG. 5 is a side view of the same. In the figure; 1... traveling crane girder, 2...
... Trolley, 3 ... Clutch, 4 ... Drive motor, 5 ... Reduction mechanism, 6 ... Hoisting drum, 7 ...
Rope, 8, 9, 10... Sheave, 11... Electric tongs, 12... Bracket, 13, 13'...
Load cell, 14, 14'... Spring holder, 15...
Spring, 16... Sheave support bearing, 17... Detection device, S... Transported object.

Claims (1)

[Scope of utility model registration request] It is mounted on a trolley that can move freely on a crane girder that can move freely, and has two drive motors connected by clutches that can be engaged and disengaged, and two motors that are driven by the drive motors through respective reduction mechanisms. A hoisting drum is disposed on the same axis, and the middle of the hanging end of two hoisting ropes having both ends attached to the hoisting drum is guided and supported by a sheave supported on a trolley,
In a tong crane equipped with two-point suspended electric tongs suspended via a sheave supported on a hanging end of a hoisting rope supported by a hoisting drum and a sheave on a trolley, the sheave on the trolley is , a load cell mounted on the trolley, having two set loads, and connected to a drive control mechanism;
The load cell is supported by a support bearing that is vertically movable supported via a spring, and when both ends of the conveyed object do not land on the floor at the same time, the detected load of the load cell on the side that landed first. When the load reaches the first set load, the lowering is stopped, the clutch is disengaged, and only the hoisting drum on the side that has not landed on the floor is lowered, and when the load detected by the load cell on the side that has not landed on the floor reaches the first set load, the lowering is stopped. Then, the clutch is engaged to wind up both hoisting drums, and when the detected loads of both load cells reach a second set load, the hoisting is stopped, and then the claws of the electric tongs are opened. Crane with tongs equipped with equipment.