JPH031233B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in ingot tongs for hoisting round, square, etc. ingots, particularly slabs.

In general, ingot tongs for hoisting a slab or the like have a pair of opposing claws (or two pairs of opposing claws) for gripping the target slab.
The tip of the opposing arm hanging down from the tong body is provided, and when this arm is expanded wider than the target slab and approached by contracting and closing to pinch this slab, and then the tongs are lifted, the claws The holder part that holds the holder is provided with a pair of arms that are guided downward and inward relative to each other, so that the pair of claws can exert a strong gripping force. Generally, a tapered sliding surface is formed between the claw holder and the arm in order to guide the downward and inward movement of the pair of claws.

By the way, this sliding surface guides the downward movement of the claw holder, but at the same time it also serves as a surface that supports the reaction force of the solid clamping of the target slab by the claws, so it is reinforced with a hard metal material, etc. However, it is difficult to manufacture products with excellent durability because several conditions are required in combination, such as maintaining the posture of the claw holder, guiding the slide, and providing a support surface for the clamping reaction force. In the past, it has been pointed out that there has been a problem of damage, particularly at the lower edge of the tapered sliding guide surface on the arm side.

Furthermore, if the clamping force when clamping the slab between the pair of claws is insufficient, there is a risk that the slab will fall after being suspended, resulting in an extremely dangerous situation.

As a result of repeated research in view of these problems, the inventor of the present invention has departed from the conventional configuration of guiding by a tapered sliding surface and has developed a mechanism for guiding the downward movement of the claw holder, and has developed a mechanism for supporting the clamping reaction force, etc. The present invention has led to the creation of a roller-based guide/support mechanism that is effective and does not impede the downward movement of the claw holder at all.

In other words, if we consider the structure of one arm in this type of tongs, the claw holder has a slight inclination with respect to the vertical direction because it is necessary to exert strong clamping force when lifting slabs as mentioned above. It is necessary to be guided downward, maintain this posture while exerting the clamping force, and by clamping and lifting the slab, the claw holder generates a rotational moment due to the force applied to the claws at the lower end (clamping reaction force). , so in order to resist this, at least 2
Various points such as the necessity of two reaction force fulcrums are cited as necessary configurations, and if these points are satisfied, the conditions for a guide/support mechanism for the pawl holder are basically satisfied.

Therefore, in the present invention, a roller that rolls into contact with the pawl holder is arranged as a part forming the two reaction force fulcrums, and the other pawl holder has a roller that rolls into contact with the pawl holder.
By forming the sliding surfaces that come into contact with these rollers so as to form a downward movement guide direction, the pawl holder can be guided and
The device is configured as a support mechanism, and is configured so that by detecting the degree of downward movement of the claw holder, it can be determined whether or not an appropriate clamping force is being obtained by the claws. .

According to this configuration, the contact engagement between the claw holder and the arm is between the flat surface and the circumferential surface of the roller, so there is no problem of edge chipping, and by ensuring sufficient positional accuracy of the roller, the claw holder The guiding direction and attitude maintenance can be achieved with high precision, and since the sliding is a rolling contact, it is extremely smooth, and various other benefits can be obtained, as well as excellent durability. It became a thing.

The gist of the present invention is to assemble a claw holder including claws for holding an ingot into the hanging arms of each of a pair of arms provided on a beam so that the spacing between them can be contracted, closed, and expanded. The ingot tongs are constructed such that the claw holders attached to these arms can be moved downwardly and inwardly relative to each other by the action of the weight of the ingot, and this downward movement increases the ingot clamping force of the pair of claws. , two sets of rollers that guide the downward movement of the claw holder by rolling are positioned at upper and lower reaction force fulcrum positions that lock the rotational moment that acts on the claw holder when the claws clamp an ingot. The ingot tongs is characterized in that the ingot tongs are rotatably attached to the arms, and the arms are provided with detection means for detecting that the claw holder moving downward reaches a predetermined limit value.

Embodiments of the present invention will be described below based on the drawings.

In FIG. 1, 1 is a slab to be lifted, 2 is a hanging ring suspended from a crane hook (not shown), and is fixed so as to be located at the center of beams 3 and 3'. 4 and 4' are arms that are slidably mounted on the beams 3 and 3' in the left and right directions in the figure, allowing them to close, close, and expand apart. claws for holding the
Equipped with a guide and support mechanism for the claw holder.

As an example of a mechanism for retracting, closing, and expanding the arms 4, 4', the arms 4, 4' are connected to drive screws 5, 5' that are driven and rotated via a motor, torque limiter, sprocket, chain (none of which are shown), etc. The female threaded blocks 6, 6' are engaged and screwed together with the arms 4, 4', and by the rotation of the drive screws 5, 5', the female threaded blocks 6, 6' connect the arms 4, 4' to the beam 3. , 3' so that it can be slid to contract, close, and expand. In addition,
Reference numbers 5' and 6' in the above description are symmetrical with reference numbers 5 and 6, and therefore illustration thereof is omitted.

Next, the claw guide/support mechanism, which is a characteristic part of the present invention, will be described. Since this mechanism has the same structure for each of the claws attached to the opposing pair of arms 4, 4', In FIGS. 2 and 3, only one side is shown.

FIG. 2 shows a state in which the arm 6 is retracted and closed, and the claw 7 is pressed into engagement with the side surface of the slab. This nail 7
is fixed at the lower end portion of the claw holder 8 on the opposing surfaces of the pair of claw holders, and the claw holder 8 is normally biased to the upper limit position by the biasing spring force of the biasing spring 9 due to the configuration described below. When lifting a slab, it is assembled so that it can be moved diagonally downward (diagonally inwardly and downwardly between a pair of opposing arms) as shown by arrow C in the figure, making an angle θ with respect to the vertical direction. That is, the bias spring built into the claw holder 8 is mounted on a spring guide support 10 and a spring guide 11 fixed to the arm 4, and
By being tensioned between the claw holder 8 and the claw holder 8, a substantially upward biasing spring force is applied to the holder 8. Furthermore, as the claws 7 clamp the slab 1, a counterclockwise rotational moment as shown in FIG. 2 acts on the claw holder 8 due to this reaction force. A pair of rollers 12 and 13 that engage with the upper inner surface and the lower outer surface of the claw holder 8 are disposed and are rotatably supported by the arm 4. Engagement surface 8a with rollers 12, 13 on the claw holder 8 side,
8b also serves as a surface that determines the downward movement direction of the claw holder 8, so it forms an inclined surface that coincides with the direction of arrow C described above. Note that these rollers 12, 1
3 is the part that supports the large clamping reaction force derived from the weight of the slab 1, so the claw holder is It is preferable to cover and fix a material having a large compressive strength different from that of the entire member 8.

With the claw holder 8 and its guide/support mechanism configured as described above, when the tongs are pulled up with a crane hook to lift up the slab 1 from the state shown in FIG.
A downward force is applied due to the weight of the Therefore, the claw holder 8 is moved downwardly and inwardly against the upward biasing spring force, and since the direction of this downward movement is the direction of arrow C in FIG. 2 as described above, the claw 7
The clamping force on the slab 1 increases as the claw holder 8 moves downward, and the downward movement of the claw holder 8 stops at the position where it balances the weight of the slab 1 (third
(see figure).

At this time, the clamping reaction force acting on the claw holder 8 is supported by the rollers 12 and 13. In addition, 14 in the figure is a limit switch 15.
This striker 14 and limit switch 15 are provided to determine the limit of downward movement of the claw holder 8. In other words, although there is a certain structural limit to the downward movement of the claw holder, when the downward movement of the claw holder reaches that limit, it is not always possible to obtain an appropriate ingot clamping force by the claws. It's not clear. However, if this clamping force is insufficient, there is a danger that the ingot may fall. Therefore, in this example, when the limit switch 15 is activated, it is assumed that the clamping force of the slab by the nails is not properly obtained, and the clamping operation can be repeated. For example, the output of the limit switch 15 is
It can be used as a signal to issue a predetermined warning to the operator of the ingot tongs.

FIG. 4 is a sectional view taken along the line A--A in FIG. 2, and shows the engagement relationship between the roller 13 and the pawl holder 8.
In this example, an oil passage is provided on the shaft 16 of the roller 13,
The lubricant can be supplied to the rotating portion of the roller 13.

According to the above configuration, the lower movement guidance and support of the claw holder 8 can be performed reliably and smoothly by the rollers 12 and 13, and moreover, it is possible to perform the downward movement guidance and support of the claw holder 8 reliably and smoothly, and moreover, it is possible to perform the downward movement guidance and support of the claw holder 8 reliably and smoothly, and moreover, it is possible to perform the downward movement guidance and support of the claw holder 8 reliably and smoothly. Since problems such as edge chipping, which was a problem in the previous method, do not occur, excellent durability can be obtained, and its usefulness is great. If a sufficient clamping force cannot be obtained, the detection means detects that the downward movement of the claw holder exceeds a predetermined limit value, and the clamping operation can be repeated, thereby preventing the ingot from falling, etc. This has the effect of preventing the dangers of

Note that the present invention is not limited to the above-mentioned embodiments, and in addition to the case in which the opposing arms are made to slide in opposite directions, one may be fixed and the other sliding, or two pairs of opposing arms may be made to slide in opposite directions. Needless to say, it can be formatted as well.

[Brief explanation of the drawing]

FIG. 1 is a front view including a partial cross section showing the general structure of the tongs according to the present invention, FIG.
The figure shows the state of the same part when lifting the slab, and FIG. 4 is a cross-sectional view taken along line A-A in FIG. 2. 1...Slab, 2...Hanging ring, 3,3'...Beam,
4, 4'...Arm, 5...Drive screw, 6...Female thread block, 7...Claw, 8...Claw holder, 8a,
8b... Engagement surface, 9... Biasing spring, 10... Spring guide support, 11... Spring guide, 12, 13...
...Roller, 14...Striker, 15...Axis.

Claims (1)

[Scope of Claims] 1. A claw holder including claws for holding an ingot is attached to each hanging arm of a pair of arms provided on a beam so that the opposing distance can be contracted/expanded, In the ingot tongs, the claw holders assembled on these arms are provided so that they can be moved downwardly and inwardly relative to each other by the action of the weight of the ingot, and this downward movement increases the ingot clamping force of the pair of claws, Two sets of rollers that guide the downward movement of the claw holder by rotation are positioned at upper and lower reaction force fulcrum positions that lock the rotational moment acting on the claw holder when the claws clamp an ingot, An ingot tong, wherein the ingot tongs are rotatably attached to each of the arms, and the arms are provided with a detection means for detecting that the claw holder has reached a predetermined limit position.