JP2008037643A - Lifter hanging implement, crane and its application method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a means for preventing claws 4 from returning in collision when releasing a lifting load 30 and preventing a lifter hanging implement from falling in the case of using the lifter hanging implement 2 for lifting the lifting load by holding both side faces of the lifting load by the claws at the tips of two moving arms 3. <P>SOLUTION: The claws 4 arranged at the tips of the moving arms 3 of the lifter hanging implement 2 are movable downward to the inside by the force applied downward. A height meter 11 for measuring a space between the lifter hanging implement 2 and the lifting load 30, and a gravimeter 21 are provided, and the variation of the space between the lifter hanging implement 2 and the lifting load 30 from the end of gripping up to lifting when gripping the lifting load is measured by the height meter 11 and set as a height moving amount L<SB>X</SB>. When unloading, landing is detected by the gravimeter 21 at the height Z<SB>5</SB>of the hanging implement, and the lifter hanging implement 2 is stopped at the height Z<SB>7</SB>of the hanging implement lowered by an amount corresponding to the height moving amount L<SB>X</SB>. The moving arms 3 are opened to release the claws 4. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a lifter lifting device that lifts both sides of a suspended load with claws at the tips of two moving arms, a crane using the lifter, and a method of using the lifter lifting device.

  As a crane that lifts steel pieces such as slabs and blooms, a tong crane is known that uses the weight of the steel pieces to lift the side with claws on the principle of leverage (for example, page C3-15 of Non-Patent Document 1, (FIG. 2.24 (b)). This hanging tool is called tong.

  The tong crane using the lever principle has a problem that when the width of the slab to be lifted is narrow, the lifting tool extends up and down, and as a result, the lift of the lifted load is reduced.

  There is known a lifting device that electrically changes the distance between two moving arms, has a claw at the lower end of the moving arm, and narrows the distance between the moving arms to lift a suspended load such as a slab with this claw. Yes. Since the lift does not change depending on the width of the slab to be lifted, there is an advantage that the storage efficiency of the slab yard is improved. This type of suspension is also sometimes referred to as a tongue or sometimes referred to as a slab lifter or lifter. Here, it will be called a lifter suspension.

  In the lifter lifting tool, in order to lift a heavy slab with a nail from the side, it is necessary to strongly hold the gripping force by the nail. If it is intended to secure this gripping force with an electric motor for reducing the distance between the moving arms, an extremely powerful electric motor is required, which is not economical.

  Then, the nail | claw arrange | positioned at the moving arm front-end | tip of a lifter hanger is arrange | positioned so that a movement to a downward inner side is possible by the force concerning a downward direction (for example, patent document 1, patent document 2). The nail is guided and held so that it can move on a line connecting the lower inner side and the upper outer side. When no downward force is applied to the nail, the nail is pulled upward by the spring force. When holding both sides of the suspended load with the claws and lifting the lifting implement together with the suspended load, if the downward force is applied to the nail due to the weight of the suspended load, the nail Move in the direction of narrowing). As the nail moves by a predetermined amount, the moving arm deforms in the direction of spreading outward, and as a result, a strong gripping force is applied to the nail to pinch the suspended load, and a heavy suspended load such as a slab is applied. It is possible to stably hold and lift.

JP 59-36091 A JP 59-227686 A "Mechanical Engineering Handbook", published by the Japan Society for Mechanical Engineering, page C3-15

  After lifting the suspended load with the lifter lifting tool and landing the suspended load at a predetermined position, the holding is released by widening the distance between the two moving arms. When releasing the grip, the suspended load will surely land, and the position of the nail will move downward and inward during lifting compared to the position of the nail when not gripped (hereinafter referred to as the “standby position”). Therefore, it is necessary to lower the lifter lifting tool until the position of the nail returns to the standby position, and release the grip at that time.

  If the crane is equipped with a weight scale and the weighing value of the weighing scale is monitored when the suspended load is landed, the weighing value is decreased by the landing, so that the landing can be detected. Therefore, landing is detected by a weight scale, where the lifting of the lifter suspension is stopped, and the holding arm is released by widening the interval between the moving arms. However, the timing at which the lifting load is detected by the weigh scale is that the lifted load has landed, but the nail of the lifter hanger has not yet returned to the standby position, and the nail has been lowered downward. . In such a situation, when the gripping is released by widening the distance between the moving arms, as soon as the claw is removed from the suspended load, the claw is instantly returned from the downward movement position to the standby position and collides with the impact of the collision. This causes a problem that the mechanism for guiding the nail is broken.

  After the landing is detected by the weighing scale, the lifter suspension is lowered by a certain amount, or the lifter suspension is lowered by a predetermined amount according to the weight of the suspended load, and then stopped and released. Can be applied. As a result, the position of the nail when releasing the grip approaches the standby position, but the amount of descent of the nail varies from time to time, and the position of the nail when releasing the grip cannot be accurately returned to the standby position. . For this reason, if the lifting amount of the lifter suspension is not sufficient, the claw guide mechanism returns and collides with the force of the spring when releasing the grip. On the other hand, if the amount of descent is too large, the wire stops due to the crane being rolled down too much. If the operation of releasing the gripping is performed in this state, the lifter lifting tool will fall by the amount of slack as soon as the nail is released. As soon as the nail is released, the lifter hanger falls, and at the moment it falls, rubbing occurs between the nail and the side of the suspended load. For this reason, the wear of the nail becomes severe, and there has been a problem that the lifetime of the nail is only about 6 months.

  Moreover, the fall of the lifter suspension caused by the slack of the wire gives a great impact to the crane body as well as the lifter suspension and adversely affects it.

  The present invention relates to a lifter lifting device that lifts both sides of a suspended load with claws at the tips of two moving arms, and a method for using the cranes having the lift, and prevents the claws from colliding when the suspended load is released. And it aims at providing the means which can prevent the situation where a lifter hanging tool falls.

That is, the gist of the present invention is as follows.
(1) A method of using a crane having a lifter lifting device 2 that lifts both sides of a suspended load 30 by grasping with two claws 4 at the tips of two moving arms 3, and the claws 4 are moved downward and inward by a force applied downward. A height meter 11 that can measure the distance between the lifter suspension 2 and the suspended load 30 and a weight meter 21 that can measure the weight of the lifter suspension 2 including the suspended load 30; The amount of change in the distance between the lifter lifting device 2 and the suspended load 30 from the end of gripping to lifting is measured with the height gauge 11 when grasping the suspended load, and the height movement amount L _X is measured. After the landing is detected, the lifter 2 is further lowered by an amount corresponding to the height movement amount L _X , the lifter 2 is stopped, and the claw 4 is opened by opening the movable arm 3. How to use the featured crane.
(2) The amount of descent of the lifter suspension 2 after the landing is detected by the weight scale 21 is a value obtained by adding a predetermined constant L _Y to the height movement amount L _X ( Use method of crane as described in 1).
(3) The above-mentioned (1) or (2), wherein the height movement amount L _X is measured as a lifter hoist winding amount from the start of hoisting of the lifter hoist at the time of lifting until the height meter measurement value becomes constant. ) How to use the crane described in the above.
(4) A method of using a crane having a lifter lifting device 2 that lifts both sides of a suspended load 30 by grasping with two claws 4 at the tips of two moving arms 3, and the claws 4 are moved downward and inward by a force applied downward. Further, a height gauge 11 for measuring the distance between the lifter suspension 2 and the suspended load 30 is provided, and the distance between the lifter suspension 2 and the suspended load 30 from the end of gripping to the lifting of the suspended load is grasped. The amount of change is measured with the height meter 11 to obtain the height movement amount L _X, and when the distance between the lifter lifting device 2 and the hanging load 30 begins to narrow when unloading, the amount of narrowing depends on the height movement amount L _X. When the change of the amount of narrowing stops, or when the amount of descent of the lifter suspension 2 after the interval starts to narrow reaches the amount corresponding to the height movement amount L _X. Stop the lifter lifter 2 from descending , The use of a crane, characterized in that to release the pawl 4 by opening the moving arm 3.
(5) A method of using a crane having a lifter lifting device 2 that lifts by holding both side surfaces of a suspended load 30 with claws 4 at the tips of two moving arms 3, and the claws 4 are moved downward and inward by a force applied downward. Further, a height gauge 11 for measuring the distance between the lifter hanger 2 and the suspended load 30 is provided, and when the distance between the lifter hanger 2 and the suspended load 30 starts to be reduced at the time of unloading, the amount of narrowing is changed. A method of using a crane characterized in that when the lift stops, the lowering of the lifter suspension 2 is stopped and the moving arm 3 is opened to open the claws 4.
(6) The lifter lifting device 2 that lifts the both sides of the suspended load 30 by grasping with the claws 4 at the tips of the two moving arms 3, and the claws 4 can move downward and inward by a force applied downward. A height meter 11 that measures the distance between the lifting device 2 and the suspended load 30, a weight meter 21 that can measure the weight of the lifter lifting device 2 including the suspended load 30, and a control device 27 are provided. The device 27 measures the amount of change in the distance between the lifter lifting device 2 and the suspended load 30 from the end of grasping to the lifting when grasping the suspended load with a height meter to obtain a height movement amount L _X , and when unloading, After the landing is detected by the weigh scale 21, the lifter 2 is further lowered by an amount corresponding to the height movement amount L _X , the lifter 2 is stopped, and the claw 4 is opened by opening the movable arm 3. Lifter suspension characterized by performing control to perform.
(7) The amount of descent of the lifter lifting device 2 after the landing is detected by the weighing scale 21 is a value obtained by adding a predetermined constant L _Y to the height movement amount L _X ( The lifter hanging tool as described in 6).
(8) A crane having the lifter suspension 2 according to (6) or (7).

The present invention is a crane having a lifter lifting device that lifts both sides of a suspended load by grasping with two claws at the tip of a movable arm, and includes a lifter suspension and a suspended load between the end of gripping and lifting when the suspended load is gripped. The amount of change in the interval is measured with a height meter to obtain the height movement amount L _{X. When} unloading, the lifter suspension is stopped by lowering the amount corresponding to the height movement amount L _X when unloading. It is possible to prevent the claw holder from being shockedly returned by the repulsive force of the spring, to prevent the lifter hanger from dropping when the grip is released, and to extend the life of the claw.

  First, the lifter suspension and the crane having the lifter will be described with reference to FIGS.

  The lifter lifting device 2 has two moving arms 3, has a claw 4 at the lower end of the moving arm 3, and lifts both sides of the suspended load 30 with the claws 4 at the ends of the two moving arms 3. . Since the suspended load 30 is often long like a slab, the suspended load is stably lifted by using two pairs of two moving arms as one pair.

  The two movable arms 3 are disposed below the hanger body 9 and can change the interval between the two movable arms 3. The moving arm 3 can be moved by, for example, an electric screw. The hanger body 9 can be wound up with a crane.

  At the lower end of the moving arm 3, a claw 4 is disposed at a position facing the two moving arms. The nail | claw 4 is guided by the guide apparatus 6, and is arrange | positioned so that a movement in the direction which connects a lower inner side and an upper outer side is possible. Here, the inner side refers to the side surrounded by the two movable arms 3. As shown in FIG. 5, as the guide device 6 for the claw 4, a claw holder 5 for holding the claw 4 is prepared, and a sliding surface 7 is arranged on the movable arm 3 so as to slide the claw holder 5. . A spring 8 is disposed on the claw holder 5 to give a force for pulling the claw 4 to the upper standby position. In FIG. 5, (a) is a moment when the suspended load 30 placed on the floor 31 is gripped by the lifter suspension 2, and the claw 4 is in the standby position. FIG. 5 (b) shows a state where the suspended load 30 is lifted by the lifter lifting device 2, and the claw 4 is moved downward and inside. In FIG. 1A, the claw 4 indicated by a solid line represents a standby position, and the claw 4 indicated by a two-dot chain line represents a position where the claw 4 has been lowered downward.

  The lifter suspension 2 is moved to the position of the suspended load 30 after the interval between the movable arms 3 is expanded beyond the width of the suspended load 30 (FIG. 2 (a)), and then the distance between the movable arms 3 is narrowed, The claw 4 is pressed against the side surface of the suspended load 30 (FIGS. 2B and 5A). When the lifter lifting device 2 is lifted in this state (FIG. 2C), the claw 4 is pulled downward by the weight of the suspended load 30 (FIG. 5B). Since the nail | claw 4 is guided by the guide apparatus 6 and moves to the downward inner side, the nail | claw space | interval which opposes tends to narrow. At this time, a strong gripping force is generated between the opposing claws.

  The lifter 2 and the crane 1 having the lifter 2 usually measure the weight of the lifter 2 including the height gauge 11 for measuring the distance between the lifter suspension 2 and the suspended load 30 and the suspended load 30. And a weighing scale 21 that can be used.

  For example, as shown in FIG. 1A, the height gauge 11 includes a winding drum 14 in a lifting device main body 9, a wire 13 disposed on the winding drum 14 is suspended, and a weight 12 is disposed at the tip thereof. The rotation angle of the take-up drum 14 can be measured by the height measuring device 15 and the position of the weight 12 can be measured based on the measured angle. The winding force of the winding drum 14 is set to a value smaller than the weight of the weight 12. When the suspended load 30 is not lifted, the weight 12 is at the lower limit position, and the lower limit position is set near the lower tip of the movable arm.

  When the lifter 2 is lowered by a crane and placed at a position where the suspended load 30 is sandwiched, the weight 12 of the height gauge 11 is at the lower limit position, so that the weight 12 contacts the upper surface of the suspended load 30. When the lifter suspension 2 is further lowered (FIG. 2A), the wire 13 for suspending the weight is wound around the take-up drum 14 as the distance between the lifter suspension 2 and the upper surface of the suspended load becomes narrower. Since the rotation angle of the winding drum 14 is measured by the height measuring device 15, the current position in the height direction of the weight 12 can be known.

  The height gauge 11 is used to detect whether or not the suspended load 30 is disposed at a position where the suspended load 30 is sandwiched. When the weight 12 comes into contact with the upper surface of the suspended load 30 and the position of the weight 12 rises to a predetermined position (FIG. 2 (a)), the lowering of the lifter suspension 2 is stopped and the interval between the movable arms 3 is reduced. Then, the suspended load is sandwiched between the claws 4 (FIG. 2 (b)), and then the lifter 2 is lifted to lift the suspended load 30 (FIG. 2 (c)).

  The height meter value L is expressed as the height decreases as the distance between the hanger body 2 and the weight 12 increases, that is, the position of the weight 12 as viewed from the hanger body 2 decreases.

  The weigh scale 21 is used to measure the weight of the suspended load 30 that is lifted. For example, the load cell 24 is arranged on the wire drum 23 for raising and lowering the lifter lifting device 2, thereby measuring the total load of the lifting device and the suspended load, and subtracting the weight of the lifting device to reduce the weight of the suspended load 30. It can be measured.

  If the suspended load amount measured by the weight scale 21 shows a predetermined value when the suspended load is lifted, it can be confirmed that the suspended load 30 has been lifted normally. Further, the lifter 2 is lowered while the suspended load 30 is suspended, and it can be confirmed that the suspended load 30 has landed when the measured value of the suspended load by the weigh scale 21 indicates near zero. .

  The lifter suspension 2 is suspended by a crane wire 22 as shown in FIG. 1A, and is lifted by winding the wire 22 around a wire drum 23. By detecting the rotation angle of the wire drum 23 with the tachometer 25, the feed amount of the wire 22 can be grasped, so that the vertical position of the lifter hanger 2 can be specified. Here, the position of the lifter hanger 2 specified in this way is referred to as a “hanger height Z”.

  First, the usage method of the 1st crane of this invention is demonstrated.

  The lifter suspension 2 is placed at the position of the suspended load 30 placed on the floor 31 (FIG. 2 (a)), the suspended load 30 is gripped (FIG. 2 (b)), and then the lifter suspension 2 is rolled up. With respect to a series of operations until the suspended load 30 is lifted (FIG. 2C), the transition of two measurement values of the lifting tool height Z and the height meter detection value L was recorded. The results are shown in FIG.

Immediately before gripping the suspended load 30 with the lifter suspension 2, the claw 4 of the lifter suspension 2 is arranged at a lateral position of the suspended load 30. The weight 12 of the height gauge 11 is in contact with the upper surface of the suspended load 30. At this position, the height of the hanger is Z ₁ and the value of the height meter is L ₁ . At this position, the claws 4 are brought into contact with both side surfaces of the suspended load 30 by narrowing the distance between the movable arms 3.

  Next, the lifter hoist 2 is started to be wound up with a crane. As the lifting tool height Z increases, the height meter value L changes in the direction of decreasing. This is because the claw 4 moves inward and downward as the lifter lifting device 2 rises, and the suspended load 30 has not yet started to rise, so that the interval between the suspended body 2 and the suspended load 30 increases.

When moving to a position where the force applied to the claw 4 can be balanced, the movement of the claw 4 stops and the change of the height gauge 11 stops. Here, the height of the hanger is Z ₂ and the value of the height meter is L ₂ . At that time, the suspended load 30 leaves the floor, and thereafter, the suspended load 30 is rolled up together with the lifting of the lifter lifting device 2. Thereafter, the value according to the height gauge is constant while the L _2.

  Next, the suspended load is landed at the landing position.

Attention is paid to the lifting tool height Z and the weighing value of the weighing scale 21 at this time (FIG. 1C). When the lifter hanger 2 is rolled down, the hanger height Z decreases accordingly. Then, at the moment when the suspended load reaches the landing position (FIG. 3B), the weighing value of the weigh scale 21 decreases at a stretch (FIG. 1C). This time is assumed to be landing detection by the weighing scale 21. The hanger height of the position and Z _5. At this position, the claw 4 of the lifter hanger 2 is still extending downward (FIG. 5B).

  The landing detection by the weighing scale 21 can be the detection of the landing when the weight value of the suspended load 30 weighed by the weighing scale 21 becomes almost zero. Moreover, it is good also as a landing detection the point where the weighing value of the hanging load 30 weighed with the weighing scale 21 decreased to a predetermined amount.

When the lifter hanger 2 is further lowered to reduce the hanger height Z, the suspended load 30 has already landed, so the distance between the lifter hanger 2 and the suspended load 30 is reduced, and the position of the claw 4 is lowered. Move upward from Then, at a certain point, the position of the claw 4 arrives at the standby position (FIG. 5A). The hanger position at this time and Z _7.

  Further, if the lifting of the lifter 2 is continued, the height Z of the lifting device continues to decrease. However, after the position of the claw 4 returns to the standby position, the suspended load 30 and the lifter 2 The relative spacing of does not change. That is, the lifter hanger 2 is not actually lowered. At this time, a slack is generated in the wire 22 between the winding drum 23 of the crane and the lifter suspension 2. When the lifter suspension 2 is lowered until sagging occurs, when the lifter suspension 2 is lowered, and when the gripping is released by widening the gap between the movable arms 3, the crane wire 22 has already been slackened. Simultaneously with the release of the grip, the lifter suspension 2 falls by the amount of slack in the wire.

Chakuyukashi the suspended load 30 is lifted by the lifter hanger 2 in landing position, as the timing for removing the pawl 4, it is most preferably carried out when the sling height is at the position of the Z _7. That is, if the position of Z ₇ can be accurately predicted, it is possible to perform the optimum grip release.

Here, a numerical value of L _X = L ₁ −L ₂ is introduced.

As a result of the study by the present inventors, as the lifting tool height Z ₇ at the time of grip release, the lifting tool height Z ₅ when the landing is detected by the weigh scale 21, the numerical value L _X , and a predetermined constant L Based on _Y
Z ₇ = Z ₅ − (L _X + L _Y ) (1)
Z ₇ is defined as follows, and when the lifting tool height reaches Z ₇ , the lowering of the lifting tool is stopped, and the holding of the moving arm 3 is widened to release the grip. I found out that it can be canceled.

That is, L _X represents that the amount of downward movement of the claw 4 (from the standby position) is considered, and in order to return the claw to the standby position at the time of landing, the lifter 2 is further lifted after the suspended load 30 has landed. Can be considered to be lowered by an amount equal to L _X. However, since there is a detection delay from the actual landing to the actual detection of landing by the weigh scale 21, a constant L _Y having the meaning of a detection delay correction coefficient is introduced, and a constant numerical value is set in advance as L _Y. By defining the above, it is possible to calculate the suspension height Z ₇ optimum for releasing the grip based on the above formula.

In calculating the lifting tool height Z ₇ for releasing the grip, an optimal function can be employed in accordance with the value of L _{X in} addition to the use of the above formula (1). The optimum function can be determined as appropriate based on the actual measured L _X value of the lifter suspension 2 and the operation result.

Accordingly, the amount of change in the distance between the lifter lifting device and the suspended load from the end of grasping to the lifting is measured with the height meter when the suspended load is grasped, and the height movement amount L _X is obtained. After detecting the landing, the lifter 2 is further lowered by an amount corresponding to the height movement amount L _X , the lifter suspension 2 is stopped, and the claw 4 is opened by opening the movable arm 3, The grip release can be suitably performed.

Moreover, it is preferable that the amount of descent of the lifter lifting device 2 after the landing is detected by the weight scale 21 is a value obtained by adding a predetermined constant L _Y to the height moving amount L _X.

When the continuous cast slab is lifted using a crane equipped with the lifter lifting device 2, the mass of the continuous cast slab of the suspended load 30 and the distance between the lifter lifting device and the suspended load from the end of gripping to the lifting of the suspended load. The amount of change was measured with a height meter, and the relationship with the height movement amount L _X was examined. The results are shown in FIG. In the figure, ■ indicates a case where one slab is hung and ◆ indicates a case where two slabs are hung. Observing the variation in L _X when the weight of the suspended load is around 40 tons, it can be seen that L _X varies from 20 mm to over 50 mm. In this case, it is clear that when the lifter suspension is lowered by a certain amount after landing detection as in the prior art, the grip release is not performed by returning the nail to the standby position. As in the present invention, the height movement amount L _X is actually measured by the height meter 11, the lift amount of the lifter suspension is determined based on the height movement amount L _X , and the grip is released. It was possible to release the grip.

By the way, when the nail 4 is gripped by the nail 4 and the lifting of the lifter lifting device 2 is started by grasping the nail 30 with the nail and the nail 4 is moving downward, Therefore, the absolute value of the amount of change in the height Z of the hanger and the amount of change in the value L of the height meter should match. Therefore, when determining the above L _X , it may be calculated as the difference between the height of the hanger Z, not as the difference between L ₁ and L ₂ as the value of the height gauge 11. Specifically, it moves to a position where the force applied to the nail can be balanced and the movement of the nail stops, and when the change in the height gauge stops, the height Z ₂ (the value of the height gauge at this time) Using L ₂ )
L _X = Z ₂ −Z ₁
L _X may be determined as follows (FIG. 1B).

  Next, the usage method of the 2nd, 3rd crane of this invention is demonstrated based on FIG.

  Lift the suspended load with the lifter lifting device 2, then lower the lifter lifting device 2 at the landing position of the suspended load 30 to land the suspended load, and finally widen the distance between the moving arms to release the suspended load. About a series of operation | movement until, the transition of two measured values, the hanging tool height Z and the height meter detected value L, was recorded. The results are shown in FIG.

Until the lifter suspension 2 is unwound and the suspended load 30 reaches the landing position, the height Z of the suspension decreases sequentially, while the value L of the height meter at this time is constant. The height meter value at this time is L ₃ . When the suspended load 30 reaches the landing position, as shown in FIG. 1 (c), the weighing value of the weigh scale 21 decreases at a stretch. At almost the same time as the weighing value of the weigh scale 21 decreases all at once, the value of the height meter that has been constant at L ₃ until then begins to rise (FIG. 4 (a)). This is because the suspended load 30 reaches the ground and the interval between the suspended load 30 and the suspension main body 9 starts to narrow. The height of the hanger when the value of the height meter 11 starts to change is set as Z _4, and is distinguished from the value L ₅ of the height meter at the moment when the weighing value of the weight meter 21 is reduced at a stroke.

When the lifter lifting tool 2 is further lowered to reduce the suspended load height Z, the height meter value L increases accordingly, and the position of the claw moves from below to above (FIG. 4). (From Z _{4 of} (a)). And the change of the value L of the height meter stops at a certain point. The height of the hanging tool at this moment is Z ₆ and the value of the height meter is L ₆ . This point represents the moment when the nail position returns to the standby position.

If the lifting of the lifter suspension 2 is continued (after Z _{6 in} FIG. 4A), the suspension height Z continues to decrease, but the height L of the height meter remains at L ₆ and does not change. As described above, after the position of the claw 4 returns to the standby position, the relative distance between the suspended load 30 and the lifter lifting device 2 that have landed does not change. That is, the lifter suspension 2 is not actually lowered. At this time, a slack is generated in the wire 22 between the winding drum 23 of the crane and the lifter suspension 2. When the lifter suspension is lowered until sagging occurs, when the lifter suspension is lowered, and when the gripping is released by widening the distance between the moving arms, the crane wire is already loosened. The lifter suspension will fall by the amount of slack in the wire.

In the second method of using the crane according to the present invention, the height change amount (L ₁ −L ₂ ) of the distance between the lifter lifting device and the suspended load from the end of the grasping to the lifting is grasped by the height gauge 11 when grasping the suspended load. The point of measuring the height movement amount L _X is the same as the method of using the first crane. In the second method, at the time of unloading, landing of a suspended load is detected based on the fact that the distance between the lifter lifting device 2 and the suspended load 30 has started to narrow. When the suspended load lands, the position of the suspended load 30 stops moving, while the lifter lifting device 2 continues to descend, so that the height as the value of the height gauge 11 begins to increase. Then, starting from the point in time when the interval between the lifter lifting device and the suspended load starts to narrow, the determination of the time point at which the lifting of the lifter suspension is stopped is made from the following three logics. First logic 4 (b), the narrowing amount (height variation from L ₃ of the measurement value) stop point when reached an amount corresponding to the height movement amount L _X And As shown in FIG. 4C, the second logic is a stop point when the change in the narrowing amount (change in the value of the height meter) stops. As shown in FIG. 4 (d), the third logic is that when the lowering amount of the lifter suspension after the interval starts to decrease reaches an amount corresponding to the height movement amount L _X , that is, the interval starts to decrease. When the amount of change in the height of the hanging tool from the height of the hanging tool Z ₄ reaches the amount corresponding to the height movement amount L _X , the stopping point is set. Thereafter, the nail is released by opening the moving arm.

As the amount corresponding to the height movement amount L _X , it is preferable to use an amount obtained by adding a constant L _Y to the numerical value L _X as in the first crane usage method.

The first of the above logic considers that the extension of the claw when gripping a suspended load is L _X , and when releasing the grip, the amount of change from the height measurement value L ₃ reaches the amount corresponding to L _X This is derived from the coincidence of when the nail returns to the standby position.

However, the value of the height meter 11 change stops in L _6. If the value of L ₆ -L ₃ is smaller than the amount corresponding to L _X , the logic 1 cannot find the suspension stop timing. Therefore, the second logic is used together. That is, even if the first logic is not established, if the change in the narrowing amount (change in the value of the height meter) stops, that point is set as the stop point.

  The third logic is a modification of the method of using the first crane of the present invention. In the first method of using the crane, the landing detection of the suspended load is detected by the change in the value of the weighing scale 21, whereas in the third logic, the suspended load is detected when the value of the height gauge 11 starts to change. It can be said that the landing detection is performed.

In the third method of using the crane of the present invention, L _X is not determined when gripping a suspended load. Also, landing detection at unloading is not performed. Attention is paid only to fluctuations in the value of the height meter when unloading (FIG. 4C). Before suspended load 30 is landed, the value of the height meter 11 is constant at L _3. When the distance between the lifter lifting device 2 and the suspended load 30 starts to narrow, that is, when the height gauge 11 changes and the height begins to increase, the suspended load has landed and the nail has started to rise. means. Then, when the change in the narrowing amount stops, that is, when the change in the value of the height meter 11 stops, it can be determined that the claw has arrived at the standby position. Accordingly, if the lowering of the lifter suspension is stopped at this time and the claw is released by opening the moving arm, the optimum grip release can be performed.

  Next, the lifter suspension 2 of the present invention will be described. The lifter hanger 2 of the present invention is a lifter hanger that can be used in the method of using the first crane of the present invention.

That is, the lifter suspension 2 of the present invention is a lifter suspension that lifts both sides of the suspended load 30 by grasping the claws 4 at the tips of the two moving arms 3, and the claws 4 are moved downward and inward by a force applied downward. Further, a height meter 11 that measures the distance between the lifter suspension 2 and the suspended load 30, a weight meter 21 that can measure the weight of the lifter suspension including the suspended load, and a control device 27, Is provided. The control device 27 measures the amount of movement of the height from the end of gripping to the lifting when gripping the suspended load as the change amount L _X of the distance between the lifter lifting device 2 and the suspended load 30 measured by the height gauge 11. At the time of lowering, after the landing is detected by the weigh scale 21, the lifter 2 is further lowered by an amount corresponding to the height movement amount L _X , the lifter 2 is stopped, and the moving arm 3 is opened to open the nail. Control to open 4 can be performed.

  By using the lifter suspension 2 having the above-described configuration, the first crane usage method of the present invention can be automatically performed.

In the lifter lifting device 2 of the present invention, as with the first method of using the crane of the present invention, the amount of descent of the lifter suspension after the landing is detected by the weighing scale 21 is the height movement amount L _X. It is preferable that the value is a value obtained by adding a predetermined constant L _Y to.

  The crane according to the present invention includes the lifter suspension according to the present invention. With this crane, it is possible to automatically realize the method of using the first crane of the present invention.

  The slab for continuous casting was handled using a crane having the shape shown in FIG. 1 and having a maximum loading weight of 90 tons. The mass of the continuous casting slab that is lifted at one time is 10 to 80 tons.

  In the conventional example, the lifting load of the lifter lifting device when lowering the suspended load is calculated based on the height position information of the lifter detected by the PLG attached to the drum of the lifter hoisting device. It was performed as if the position was reached, and the grip was released there. In this method, the lifter lifting device has a lower descent and the claw holder collides with the standby position when the grip is released. . For this reason, the wear of the nails was severe, and it was necessary to replace the nails every 6 months.

Next, the usage method of the 1st crane of this invention was applied as an example of this invention. The height movement amount L _X was measured with a height meter, and an optimum constant was determined by actual measurement for the detection delay correction coefficient L _Y. Based on the height movement amount L _X , a predetermined constant L _Y , and the lifting tool height Z ₅ at the time of landing detection by the weigh scale 21,
Z ₇ = Z ₅ − (L _X + L _Y )
As defined and Z _7, hanger height stops lowering the hanger when it reaches the Z _7, to release the grip here extends the distance of the movement arm.

  In the example of the present invention, the number of cases where the claw holder moves shockingly when the grip is released and the case where the lifter hanger falls are drastically reduced. As a result, the result that the nail life was extended from 6 months to 1 year or more was obtained.

  In addition, since the frequency of the lifting of the lifter suspension caused by the slack of the wire has been drastically reduced, the adverse effect on the lifter suspension and the crane due to the impact at the time of the fall could be greatly reduced.

(A) is a figure which shows the lifter hanger of this invention, (b) is the change state of hanger height Z and height meter L at the time of lifting, (c) is hanger height Z at the time of hanging unloading It is a figure which shows the change condition of a weighing scale weighing value. It is a figure which shows the operation | movement at the time of lifting of the lifter lifting tool of this invention, (a) is the condition immediately before holding | grip, (b) is the condition immediately after holding | grip, (c) is starting lifting, and a suspended load leaves a floor. It is a figure which shows the condition immediately before. It is a figure which shows the operation | movement at the time of unloading of the lifter hanging tool of this invention, (a) is the situation immediately before landing, (b) is the situation immediately after landing, (c) is the situation immediately before releasing the grip after landing. FIG. It is a figure which shows the change condition of the hanging tool height Z at the time of hanging load unloading, and the value L of a height meter. It is the partial schematic sectional drawing which shows the condition of the nail | claw of a lifter hanging tool, (a) is a figure which shows the condition where a nail | claw exists in a standby position, (b) is a figure which shows the condition where the nail | claw extended below. It is a diagram showing the relationship between the height movement amount L _X of the load and the height meter suspended load.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Crane 2 Lifter lifting device 3 Moving arm 4 Claw 5 Claw holder 6 Guide device 7 Sliding surface 8 Spring 9 Lifting device main body 11 Height meter 12 Weight 13 Wire 14 Winding drum 15 Height measuring device 21 Weighing scale 22 Wire 23 Wire drum 24 Load cell 25 Tachometer 27 Controller 30 Suspended load 31 Floor

Claims (8)

A method of using a lifter having a lifter lifting device which lifts both sides of a suspended load with claws at the tips of two moving arms, wherein the claws can be moved inwardly by a force applied downward, and the lifter lifting device Lifter for measuring the distance between the lifting load and the lifting load, and the weighing scale that can measure the weight of the lifter lifting device including the lifting load. The amount of change in the distance between the implement and the suspended load is measured with a height meter to obtain the height movement amount L _X, and when the load is unloaded, the landing is detected with the weigh scale and the lifter suspension device is further moved to the height movement amount. A method of using a crane, wherein the lifter is lowered by an amount corresponding to L _X , the lifter suspension is stopped, and the pawl is opened by opening the moving arm. The amount of descent of the lifter suspension after the landing is detected by the weight scale is a value obtained by adding a predetermined constant L _Y to the height movement amount L _X. How to use a crane. 3. The crane according to claim 1, wherein the height movement amount L _X is measured as a lifter hoisting amount from a start of hoisting of the lifter hoist at the time of hoisting until a height meter measurement value becomes constant. how to use. A method of using a lifter having a lifter lifting tool that lifts both sides of a suspended load with claws at the tips of two moving arms, wherein the claws can be moved downward and inward by a force applied downward, and the lifter lifting tool A height gauge is used to measure the distance between the lifter and the suspended load. and the amount L _X, during unloading, the Once started narrowing the distance between the suspended load and the lifter hanger, when the amount of narrowing reaches an amount corresponding to the height shift amount L _X, or narrowing of the change is stopped Or when the amount of descent of the lifter lifting device after the interval begins to decrease reaches the amount corresponding to the height movement amount L _X , the descent of the lifter suspension is stopped and the moving arm is opened. To open the nails How to use the crane to feature the door.   A method of using a lifter having a lifter lifting tool that lifts both sides of a suspended load with claws at the tips of two moving arms, wherein the claws can be moved downward and inward by a force applied downward, and the lifter lifting tool The height gauge that measures the distance between the lifter and the suspended load is equipped.When the distance between the lifter lifter and the suspended load begins to narrow when unloading, the lifter lifter stops descending when the change in the amount of narrowing stops. A method of using a crane, characterized in that a claw is opened by opening a moving arm. A lifter lifting device that lifts both sides of a suspended load with claws at the tip of two moving arms, and the claw can be moved inward by a force applied downward, and the distance between the lifter lifting device and the suspended load. A height meter that measures the weight of the lifter, including a suspended load, and a control device. The amount of change in the distance between the lifter lifting device and the suspended load is measured with a height meter to obtain the height movement amount L _X, and when the load is unloaded, the landing is detected with the weigh scale and the lifter suspension device is further moved to the height. A lifter suspension characterized in that the lifter suspension is lowered by an amount corresponding to the amount of movement, and the lifter suspension is stopped, and the claw is opened by opening the movable arm.   The lifter lifting device according to claim 6, wherein the lowering amount of the lifter lifting device after the landing is detected by the weight scale is a value obtained by adding a predetermined constant to the height movement amount. .   A crane comprising the lifter suspension according to claim 6 or 7.

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