JPH0796438B2 - Multi-stage boom support mechanism - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to a crane for moving a hook up and down to lift a heavy load, and a lift for moving a lift up and down above a vehicle to store personnel, materials, and the like. Regarding a telescopic multi-stage boom used in a lifting device that can be lifted to a high place, in particular, the load applied to the tip of the multi-stage boom is partially borne by a flexible connecting band, and the multi-stage boom is The present invention relates to a support mechanism for a multi-stage boom that can prevent bending.

[Conventional technology]

A mechanism is often used in which a crane is attached to the body of a truck and the like, and a heavy object is lifted by operating the crane to load and unload cargo.

For assembling, painting, and repairing in high places such as highways and building construction, many aerial work vehicles that raise and lower the elevator are used, and workers, materials, etc. are placed on the elevator and lifted from the ground. , There is more work to drop from higher places.

In these conventional cranes, aerial work vehicles, etc., a multi-stage boom is often used in which a plurality of booms having different outer shapes are telescopically inserted and can be expanded and contracted in the length direction. Met.

In this multi-stage boom, the total length is extremely reduced when the length is reduced, and when extended, the total length becomes longer, and the total length is limited, such as with a truck-mounted crane or a boom-type aerial work platform. One mechanism has the advantage that it can shorten the overall length of the boom during movement, and has been widely used.

However, in the multi-stage boom mechanism, a plurality of booms having different outer shapes are assembled in a telescopic shape, and the number of parts where the members slide increases. For this reason, there is a problem that rattling increases and the tip easily swings up and down due to wind and load when extended for a long time. Then, in order to lift a heavy object, it is necessary to increase the strength of each boom, which increases the weight of all booms. Also, each boom is made of metal, but when a load is applied to the tip, the entire boom bends due to the load and deforms into a bow, so if a large load is hung, the boom will move in the length direction. In some cases, it could not be slid smoothly.

[Problems to be solved by the invention]

As described above, in the conventional multi-stage boom, the total length can be shortened at the time of contraction, but in order to withstand a large load, each boom must be made strong and strong, resulting in a heavy weight. That is, they had contradictory drawbacks. In addition, the phenomenon that each boom bends when a load is applied, but the sliding points between each boom must be manufactured so that they can slide accurately even in the bent state, and high machining accuracy is required. It was something that was done.

[Means for solving problems]

The present invention provides a multi-stage boom having a telescopic shape by slidably inserting a plurality of stages of booms, and an operating rod that is swingably fixed to the lower end upper surface of the bottom boom of the multi-stage boom. , The lower end of each boom is connected to the lower end of the boom, and it is pulled out from the upper end of the lower boom, inverted at the upper end of the lower boom control rod, and connected to the upper end of the boom control rod. The lower end of the first stage boom is connected to the lower end of the boom of the first stage, and is pulled out from the upper end of the boom of the second stage, inverted at the upper end of the control rod of the second stage boom, and then the upper end of the boom of the first stage. And a connecting belt for pulling between the upper end of the operating rod attached to the lowermost boom and the upper end of the control rod of the boom, and a connecting belt that operates according to the expansion and contraction amount of the multistage boom It consists of a correction mechanism that controls the tilt angle of the rod. It is intended to provide a multi-stage boom support mechanism according to claim.

[Action]

In the present invention, the control rod is swingably connected to the upper surface of the tip of the boom other than the uppermost boom among the multi-stage booms, and a pair of connecting bands is connected from the tip of each boom to the inside of each boom. , The two connecting bands are inverted at the upper end of the control rod, one connecting band is connected to the upper end of the connecting rod at the front stage, and the other connecting band is connected to the base of the connecting rod at the front stage. The top end of the connecting band, which is pulled out from the end of the second control rod, is connected to the uppermost boom, and the connecting band is assembled to form a triangular shape. And
A swingable operating rod is connected to the lower portion of the lowermost boom, and the control rod and operating rod of the lowermost boom are connected by a pulling wire. Further, the operating rod is designed so that its inclination angle can be corrected by a correction mechanism.

With this configuration, when each boom is pulled out, the connecting strip having the same length as the length of each boom that is pulled out is pulled out from the control rod, and acts so as to pull up the top part of the uppermost boom. Therefore, by changing the inclination angle of the operating rod of the lowermost boom, the tip of the boom at the uppermost stage is pulled up by the connecting belts that are sequentially connected, so that each boom is not bent by the load and the multistage boom Always keep the boom in a straight line. Since the correction mechanism corrects the tilt angle of the operating rod in accordance with the amount of expansion and contraction of the multi-stage boom, the tilt angle of the connecting band holding the uppermost boom is always maintained to be an isosceles triangle. For this reason,
Bending of the upper stage of the multi-stage boom can be suppressed.

That is, since the multistage boom is pulled in the direction opposite to the direction in which it is bent by the connecting band, it is held in the direction opposite to the direction in which the load is always applied, and the stress applied to the multistage boom can be reduced. Therefore, the multi-stage boom does not bend due to the load, and since the multiple booms are always arranged in a straight line, sliding is smooth, and the strength of each boom can be reduced compared to the conventional ones. The weight can be reduced.

〔Example〕

 An embodiment of the present invention will be described below with reference to the drawings.

In this embodiment, an example in which the present invention is applied to a work vehicle with a crane equipped with a crane mechanism will be described.

A cabin 2 on which a driver or the like rides is provided on the front surface of a vehicle body 1 that houses an engine and the like, and front wheels 3 and rear wheels 4 are pivotally supported at the front and rear portions of the vehicle body 1. Outriggers 5 for fixing the vehicle body 1 in a fixed position are projected on the front, rear, left and right sides of the vehicle body 1. A swivel base 6 is attached to the rear portion of the upper surface of the vehicle body 1 so as to be rotatable in the horizontal direction, and a holder 7 is mounted and fixed on the swivel base 6. A lower boom 9 is swingably connected to an upper portion of the holding body 7 by a pin 8, and a middle boom 10 is slidably inserted into an upper end opening of the lower boom 9 to allow the middle boom 10 to move freely. A tip boom 11 is slidably inserted through the upper end opening. The lower boom 9, the middle boom 10, and the front boom 11 form a boom mechanism that can be expanded and contracted in its length direction.

A hydraulic cylinder 12 for controlling the depression angle is interposed between the holder 7 and the lower boom 9. A head 13 is attached to the tip of the tip boom 11,
A suspension wire 14 is suspended downward from the head 13, and a hook body 15 and a hook 16 are suspended under the suspension wire 14. An operating rod 17 is swingably provided on the lower upper surface of the lower boom 9.
This operating rod 17 has a correction mechanism consisting of four hydraulic cylinders.
The correction mechanism 20 controls the swing angle of the operating rod 17.

A control rod 18 is swingably provided on the upper end surface of the lower boom 9, and a control rod 19 is also provided on the upper end surface of the middle boom 10.
Is swingable. The upper end of the operating rod 17 and the control rod
A pull wire 21 is stretched between the upper end of the wire 18. A wire as a connecting band is provided on the upper end of the control rod 19.
22 is connected, and this wire 22 is inverted downward at the upper part of the control rod 18 and drawn inside from the tip opening of the lower boom 9, and the other end of the wire 22 is connected to the lower end of the middle boom 10. . Further, a wire 23 as a connecting band is connected to the upper surface of the tip of the front boom 11, and the wire 23 is inverted at the upper part of the control rod 19 and drawn into the inside from the upper end opening of the middle boom 10. The other end is a tip boom 11
Is connected to the lower end of.

Next, FIG. 2 explains in detail the internal structure of the telescopic boom.

The inside of the middle boom 10 is hollow, and the inside of the middle boom 10 is provided with a hydraulic cylinder 25 along the length direction thereof. The cylinder rod 26 of the hydraulic cylinder 25 is directed toward the lower boom 9, and the tip of the cylinder rod 26 is connected to the lower portion of the lower boom 9. Further, a tuning wire 38 is connected to the lower end of the front boom 11, the wire 38 is inverted at the lower end of the middle boom 10, and the other end is connected to the upper end of the lower boom 9. Further, a tuning wire 39 is connected to the lower end of the front boom 11, the wire 39 is inverted at the upper end of the middle boom 10, and the other end is connected to the upper end of the lower boom 9. The three booms 9, 10, 11 are synchronized by the wires 38, 39, and the front boom 11 slides over the middle boom 10 at a speed at which the middle boom 10 slides over the lower boom 9.

Further, a guide body 27 having a slightly U-shape is fixed to the upper surface of the lower boom 9 substantially at the center thereof, and a slider 28 is inserted into the internal space of the guide body 27.
28 is guided so as to be movable in the length direction of the lower boom 9. A connecting rod 29 is fixed to the left and right of the lower boom 9, and hydraulic cylinders 30 and 31 are connected to the connecting rod 29 so as to be vertically parallel. The cylinder rods of these hydraulic cylinders 30 and 31 are connected to the operating rod 17 at intervals, and are arranged in a V-shape by the hydraulic cylinders 30 and 31.

Next, FIG. 3 is an enlarged view of the vicinity of the correction mechanism 20.

A slider 28 is inserted in the guide body 27, the axis of the slider 28 is oriented substantially at right angles to the axis of the lower boom 9, and the slider 28 itself is movable in the length direction of the lower boom 9. Has become. Further, connecting rods 29 and 32 are fixed to the left and right of the slider 28, hydraulic cylinders 30 and 31 are connected to the connecting rod 29, and hydraulic cylinders 33 and 34 are connected to the connecting rod 32, respectively. ing. The cylinder rods of the hydraulic cylinders 31 and 34 are connected to a swing shaft located under the operating rod 17. Further, the cylinder rods of the hydraulic cylinders 30 and 33 are respectively connected to both sides of the center of the operating rod 17, and are arranged by the hydraulic cylinders 30 and 31 and the hydraulic cylinders 33 and 34 so as to be slightly V-shaped. ing.

Next, FIG. 4 shows a control rod 18 at the tip of the lower boom 9.
It will be described in detail in the vicinity of.

A control rod 18 is swingably connected to the upper end upper surface of the lower boom 9 by a pin 35, and a pulley is attached to the upper end of the control rod 18.
36 is pivotally supported, and a pulley 37 is pivotally supported below the control rod 18. Then, the wire 22 is inverted by the pulley 36 and directed downward, and further guided by the pulley 37 into the inside from the tip opening of the lower boom 9, and the other end of the wire 22 is inside the lower boom 9 and the lower end of the middle boom 10 is inside. Is connected with.

Next, FIG. 5 shows a hydraulic piping diagram in this embodiment, in which only the mechanism of the telescopic boom is described.

A hydraulic pump 40 driven by the engine 41 is connected to an oil tank 42 on the suction side, and a switching valve on the discharge side of the pump 40.
Connected to 43. The discharge side of the switching valve 43 is connected to the oil tank 42. The output of the switching valve 43 is connected to the boom expansion / contraction hydraulic cylinder 25, and the correction hydraulic cylinder is provided on the discharge side of the hydraulic cylinder 25.
30, 31, 33 and 34 are connected in parallel. The discharge sides of the hydraulic cylinders 30, 31, 33, 34 are arranged in parallel and connected to the switching valve 43.

Next, the operation of this embodiment will be described.

First, the engine 41 is operated and the hydraulic pump 40 is operated. Then, the pressure oil stored in the oil tank 42 is supplied to the switching valve 43. Here, when the switching valve 43 is switched to the forward direction, the pressure oil is transmitted to the hydraulic cylinder 25, and the hydraulic cylinder 25 extends. At the same time, the pressure oil discharged from the hydraulic cylinder 25 is transmitted to the hydraulic cylinders 30, 31, 33, 34, and these hydraulic cylinders 30, 31, 33, 34 also expand at the same time.

First, the extension of the multistage boom will be described. As the hydraulic cylinder 25 extends, the cylinder rod 26 is pushed out, and the middle boom 10 is pushed out from the lower boom 9. When the middle boom 10 is pushed out from the lower boom 9, the tuning wires 38 and 39 are also moved at the tip of the middle boom 10. Therefore, the front boom 11 connected to the wires 38 and 39 is also moved to the middle boom 10 at the same time. It will be pushed out from the tip. Therefore, the movement of the hydraulic cylinder 25 causes the middle boom 10 and the front boom 11 to be pushed out from the lower boom 9 in synchronization with their movement amounts. Simultaneously with this operation, when the middle boom 10 is pushed out from the lower boom 9, the wire 22 is pulled out from the tip opening of the lower boom 9, and the wire 22 is fed out through the control rod 18 so as to be parallel to the middle boom 10. Will be done. Similarly, when the tip boom 11 is pushed out of the middle boom 10, the tip boom
The wire 23 connected to 11 is drawn out through the operating rod 19 and is drawn out in a triangular shape.

Further, since the pulling wire 21 stretched between the operating rod 17 and the control rod 18 is always pulled, the pulling wire 21, the wires 22 and 23 are always in a pulling state, and the tip of the tip boom 11 is Is always pulled in the opposite direction of the downward load. As described above, in synchronization with the operation of the hydraulic cylinder 25, the hydraulic cylinders 30, 31, 33,
34 will also grow at the same time. For this reason, the connecting rods 29, 32 are actuated by the hydraulic cylinders 30, 31, 33, 34 extending.
It will be extruded in the opposite direction to 17 and the slider
28 is moved while sliding on the surface of the lower boom 9. Then, since the V-shaped shape formed by the combination of the hydraulic cylinders 30, 31 and the hydraulic cylinders 33, 34 forms an acute angle, the operating rod 17 is lifted in the direction perpendicular to the axis of the lower boom 9, and the pulling wire 21 is pulled. Always acts to pull up. Because of this, the pull wire
The control rods 18 and 19 which are interlocked with the 21 are raised in synchronization with the tilting angle of the operating rod 17, keeping the wire 22 parallel to the axis of the middle boom 10 while keeping the wire 23 from the front boom 11 and the control rod. The triangle formed by 19 and 19 is corrected so as to always maintain the shape of an isosceles triangle.

In this way a multi-tiered boom and multiple wires 21, 22, 23
Will operate in conjunction with each other, and the situation of the operation will be described with reference to FIGS. 6 and 7.

FIG. 6 shows a state in which the multi-stage boom is contracted to the shortest, and in this case, the operating rod 17 and the control rod are
18 and 19 are inclined to the left in the figure, respectively, and the tip boom 11 is hung by a wire 23. Actuating the hydraulic cylinder 25 will cause the middle boom to
10, the front boom 11 is pulled out from the lower boom 9 and moves in the direction A in the figure. This middle boom 10, front boom 11
Since the moving amount of each wire is the same, the wires 22, 23
Is the same as the amount that is drawn. There, the middle boom 10,
As the front boom 11 is pulled out from the lower boom 9, the operating rod 17 is raised in the direction of arrow B by the correction mechanism 20, and this movement in the B direction is transmitted to the control rods 18 and 19 by the pulling wire 21. The control rods 18 and 19 are raised in the directions of arrows C and D, respectively.

With such a procedure, the middle boom 10 and the front boom 11 are pulled out to some extent, and the operating rod 17 is started up.
In this state, the control rod 19 is corrected in accordance with the extension amount of the front boom 11 by the corrected angle of the operating rod 17, and the inclination angle thereof is raised.
Therefore, the angle α formed by the wire 23 and the control rod 19,
The angle α formed by the tip boom 11 and the control rod 19 is modified so as to be always equal.

Thus, since the load applied to the tip of the front boom 11 is always pulled up by the wires 23, 22 and the pulling wire 21, the bending moment with respect to the front boom 21, the middle boom 10 is absorbed, and the front boom 11, the middle boom 10 is absorbed. Is corrected so that it will not bend. Therefore, the front boom 11 and the middle boom 10 always maintain the linear shape, and the extension and contraction operation for the lower boom 9 becomes extremely smooth.

FIG. 8 shows an example in which the present invention is applied to an aerial work vehicle used to lift personnel and materials to a high place.

In this embodiment, a front wheel 52 and a rear wheel 53 are provided on the front, rear, left and right of the vehicle body 51.
Is rotatably supported so that the vehicle body 1 can move freely, and a work body 54 is horizontally rotatably mounted on an upper portion of the vehicle body 51.

On the upper surface of the work body 54, a pair of shaft support pieces 55 with a slightly triangular shape is formed.
The lower boom 56 having a square cross section is inserted between the shaft support pieces 55, and the lower boom 56 is pivotally supported by a pin 57 so that the lower boom 56 can swing up and down. Has been done. The middle boom 58 is inserted through the tip opening of the lower boom 56, and the tip boom 59 is inserted through the tip opening of the middle boom 58. The lower boom 56, the middle boom 58, and the front boom 59 form a multistage boom.

At the tip of the tip boom 59, a bucket 60 on which people, materials and the like are placed is attached. The work unit 54 and the lower boom 56
A hydraulic cylinder 61 for depressing is interposed between and.

A work rod 62 is connected to the upper surface of the lower portion of the lower boom 56, and the work rod 62 has a correction mechanism for correcting this angle.
63 are connected. Further, control rods 64 and 65 are connected to the upper end surface of the lower boom 56 and the upper end surface of the middle boom 58, respectively. A pulling wire 66 is installed between the work rod 62 and the control rod 64, and a wire 67 is connected to the upper end of the control rod 64. The wire 67 is reversed by the control rod 64 and is attached to the lower boom 56. Is inserted through the upper end opening and the other end is connected to the lower end of the middle boom 58. In addition, the boom ahead
A wire 68 is connected to the upper end of 56.
68 is inverted at the upper end of the control rod 65, enters the inside of the middle boom 58 through the front end opening of the middle boom 58, and the other end of the wire 68 is connected to the lower end of the front boom 59.

During operation in this aerial work vehicle, the middle boom 58,
At the same time when the tip boom 59 expands and contracts, the wires 66, 67, 68 are pulled in synchronization with each other, and the loads applied to the tip of the tip boom 58 are lifted by the wires 66, 67, 68, and the booms 56, 58, 59 are Prevents bending.

〔effect〕

Since the present invention is configured as described above, in the telescopic multi-stage boom, the wire that has been retracted at the same time as the boom expands and contracts is pulled out, and the pulling out angle of the wire is held so that it is always pulled. Since the wire can bear the load applied, it is possible to absorb the bending force applied to each boom of the multi-stage boom and prevent the boom from bending.
Therefore, the axis line of each boom in the multi-stage boom is always maintained in a straight line, and sliding between the booms is maintained extremely smoothly.

Further, since each wire can bear a part of the load, the strength of the multi-stage boom can be reduced and the overall weight can be reduced.

[Brief description of drawings]

FIG. 1 is a perspective view illustrating an embodiment of the present invention for a vehicle with a crane, FIG. 2 is a cross-sectional view showing the internal structure of the above-described multistage boom, and FIG. 3 is an enlarged perspective view showing the vicinity of a correction mechanism. FIG. 4 is an enlarged perspective view showing the vicinity of the control rod, FIG. 5 is a piping diagram showing a hydraulic system in this embodiment, and FIG. 6 is a case where a multistage boom is contracted to explain the operation of the present invention. Explanatory drawing, FIG. 7 is explanatory drawing which shows operation | movement in the case of extending the multistage boom among operation | movement in this invention, and FIG. 8 is a side view which shows other Example of this invention. 9 …… Lower boom, 10 …… Middle boom, 11 …… Front boom, 17
...... Actuating rod, 18, 19 ...... Control rod, 20 ...... Correction mechanism, 21 ...
… Pull wires, 22, 23… Wires as connecting bands.

Claims (1)

[Claims] 1. A multistage boom which is telescopically formed by slidably inserting a plurality of stages of booms, and an operating rod which is swingably fixed to the upper surface of the lower end of the lowermost boom of the multistage boom. And the lower end of each boom is connected to the lower end of the boom, and the lower boom is pulled out from the upper end of the boom.The lower boom is inverted at the upper end of the control rod and connected to the upper end of the boom control rod. The lower end of the boom of the first stage is connected to the lower end of the boom of the first stage, and it is pulled out from the upper end of the boom of the second stage. Corresponding to the amount of expansion and contraction of the multi-stage boom, the connecting band connected to the upper end, the connecting band for pulling between the upper end of the operating rod attached to the lowermost boom and the upper end of the control rod of the boom. From the correction mechanism that controls the tilt angle of the operating rod Multi-stage boom support mechanism characterized by Rukoto.