JPH0217478B2 - - Google Patents

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a lifting device used for lifting workers or materials and lowering unnecessary parts for work at high places, and in particular, Regarding the lifting device in which a pair of middle booms are pivoted in an X-shape, and an upper boom and a lower boom that extend and contract in the axial direction are inserted through each middle boom, the middle boom, upper boom, and lower boom are compared to the amount of expansion and contraction of the hydraulic cylinder. The present invention relates to an elevating device that can extend and retract a telescopic boom body consisting of a boom to a high height.

[Conventional technology]

Lifting devices that raise and lower platforms are often used for assembly, painting, and repairs at high places such as highways and building construction. They were tasked with loading and unloading construction materials.

In this conventional lifting device, a pair of arms are pivoted at the center to make one set, and a pantograph-like extension mechanism is used in which multiple sets of arms are connected in the vertical direction (so-called scissor type). In order to increase the maximum lifting height of the lifting device, it is necessary to increase the length of each set of arms or to increase the number of connected arms. For this reason, when designing a lifting device that can increase the height that can be lifted, multiple sets of pantographs must be used, which increases the height of the lifting device when the pantographs are folded, making it difficult for workers to get on and off the platform. The work of loading and unloading materials was cumbersome.

In order to eliminate this drawback, various proposals have been made in the past, including a structure as disclosed in US Pat. No. 3,820,631. In this proposed structure, a lower boom and an upper boom that can move in a straight line with respect to the middle boom are inserted into the middle boom so that they can be inserted and removed, and the lower end of the lower boom is pivotally supported on the vehicle body side with a pin. The upper end of the upper boom is pivotally supported on the platform with pins, forming an X-shape. With this structure, the length of the boom itself becomes longer, so the height of the platform can be lowered when folded, and the height of the platform can be lowered.
This allows the platform to be raised to a higher position.

However, in this invention, the mechanism that extends the lower boom and the upper boom from the middle boom is composed of a screw and a female screw that engages with the screw, so the expansion and contraction movement speed of the lower boom and upper boom with respect to the middle boom is slow. It was impossible to make the platform respond. In addition, a mechanism for moving the middle boom in a straight line using screws and female screws is housed inside the middle boom, so in the case of initial lifting, if a pair of middle booms are moved straight in parallel, the force will be applied upward. is something that cannot be directed towards. For this reason, the platform cannot be lifted;
Early platform lifting operations required a kick mechanism to push the platform slightly upward. In addition, since the lower and upper booms are operated by screws located in the center of each middle boom, their total length can only be set to about half the length of the middle boom. The extension length of the upper boom was only about half the length of the middle boom, and the structure was such that the platform could not be lifted higher.

Also, a structure has been proposed in which another boom is inserted into the boom to lengthen the entire length of the boom itself. For example, Patent Publication No. 119556
In Figure 4 of the drawing, the lower and upper booms with narrower diameters are inserted into the middle boom with a thicker diameter, and the lower and upper booms inserted inside are pulled out from the middle boom to open the boom. A structure has been devised that increases the overall length and lifts the platform higher.

However, in this structure, there is no mechanism to synchronize the amount of expansion and contraction between the lower boom and the upper boom, which are pulled out from the middle boom, and each moves independently, and the amount of movement is determined by a link mechanism using a bar. It is regulated. For this reason,
The platform cannot be lifted vertically or horizontally to a desired vertical height. In addition, when the lower boom and upper boom housed in the middle boom expand and contract, the movement is controlled by links formed by bars, so that the movement of the lower boom and upper boom is restricted.
Since complete synchronization of the travel distance is impossible, it is not possible to connect the lower boom to the vehicle body and the upper boom to the platform with pins, etc., and errors in synchronization are caused by rollers in contact with the vehicle body and platform. This is something that must be done.
For this reason, the platform suffers from the accumulation of looseness due to the large number of pivot points provided by the link mechanism, as well as the rolling motion caused by the rollers, resulting in a structure that is susceptible to shaking.
It was extremely unstable, easily swaying due to wind, etc., and caused workers to feel uneasy. Additionally, the hydraulic cylinder was installed between the middle booms that formed an X shape, and although it was easy to open and close the middle boom, it was not possible to lift the middle boom directly above the vehicle body. .

For this reason, a lifting device has been devised in which a plurality of booms are telescopically inserted into the inside of the arm so that one arm can extend in its length direction (for example, Japanese Patent Application No. 134487 No., special request 1982
191065 etc.).

The outline of this newly proposed lifting device is explained with reference to Fig. 1.The middle boom A, which is hollow inside,
B is rotatably connected in an X-shape by an axis C at its center, and upper booms D and E and lower booms F and G are inserted into the end faces of middle booms A and B, respectively, so that they can appear and retract. Yes, upper boom D, E
A lifting platform I is connected to the lower boom F, G.
is connected to base H. Then, when the shaft C is raised by a hydraulic cylinder or the like, the upper booms D and E and the lower booms F and G are pulled out from the open ends of the middle booms A and B, and the platform I is moved away from the base H and directed upward. Rise.

Here, in order to raise the lifting platform I vertically upward with respect to the base H, a hydraulic cylinder is interposed between the base H and the shaft C, and the upper boom D is moved by the expansion and contraction force of the hydraulic cylinder. , E, and the lower booms F and G can be pulled out from the open ends of the middle booms A and B, respectively. However, with this structure, the height that the platform I can rise to is determined by the amount of expansion and contraction of the hydraulic cylinder.In order to increase the rising height, the amount of expansion and contraction of the hydraulic cylinder must be increased. There was a limit to the amount. Furthermore, the use of a hydraulic cylinder with a large amount of expansion and contraction has the disadvantage of increasing the price.

[Problem that the invention seeks to solve]

The present invention provides a lifting device that eliminates the above-mentioned drawbacks, and its purpose is to increase the overall amount of expansion and contraction by using a hydraulic cylinder with a short amount of expansion and contraction, thereby increasing the amount of expansion and contraction from the platform I. To provide a lifting device that can be lifted to a higher position than a platform H.

[Means for solving problems]

The present invention consists of a movable vehicle body, a lifting platform located above the vehicle body that can be raised and lowered, a pair of middle booms rotatably supported in the center and combined in an X shape, and a length of each middle boom. move relative to the direction,
a lower boom whose lower ends are connected to the vehicle body;
In a lifting device that has an upper boom that moves in the length direction of each middle boom and whose upper end is connected to a lifting platform, the lower boom and upper boom of each middle boom are connected to move both. a flexible linkage means for regulating the amount; a conversion means provided on the middle boom for changing the direction of movement of the linkage means; In the elevating device, the elevating device comprises a pair of telescoping mechanisms arranged in the vertical direction to vertically lift the elevating platform, wherein both the telescoping mechanisms have longitudinal openings and their lower ends swing against the vehicle body. The storage cylinder is inserted into the through-opening of the storage cylinder so as to be movable in its length direction, and the upper end of the storage cylinder is connected to the center of rotation of the middle boom so as to be swingable. A hydraulic cylinder whose cylinder rod can be expanded and contracted along the length of the body, one end of which is connected to the vicinity of the opening of the storage cylinder, the other end connected to the cylinder rod of the hydraulic cylinder, and the middle part of the cylinder rod is inserted into the storage cylinder. and a wire that is brought into contact with the base of the hydraulic cylinder, and when the hydraulic cylinder extends, the wire is pulled out from the housing cylinder, and when the wire is pulled out, the hydraulic cylinder itself is also pulled out from the housing cylinder, The present invention provides an elevating device that operates with the distance between the lower end of the storage cylinder and the tip of the cylinder rod being approximately twice the amount of extension of the hydraulic cylinder.

[Effect]

In the present invention, the lower boom and the upper boom are movably inserted into the middle boom, and by lifting the middle boom, the upper boom is moved by a pair of telescoping mechanisms arranged in a V-shape between the vehicle body and the middle boom. The upper boom is pulled out from the middle boom, and at the same time the upper boom is pushed out from the middle boom by the connecting means.
As a result, the lifting platform is raised. In this telescopic mechanism, a hydraulic cylinder is movably inserted into the housing cylinder, and when the cylinder rod of the hydraulic cylinder is extended, a wire connected to the cylinder rod is pulled out. One end of this wire is connected to the storage cylinder, and since the length of the wire does not change, the hydraulic cylinder acts to be pulled out from the storage cylinder. Therefore, the distance from the base of the storage cylinder to the tip of the cylinder rod is twice the amount of expansion and contraction of the hydraulic cylinder, and the middle boom is lifted higher, resulting in the lifting platform being raised higher than the amount of expansion and contraction of the hydraulic cylinder. I will do it.

〔Example〕

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

The reference numeral 1 in the figure is a truck body.A front wheel 2 and a rear wheel 3 are pivotally supported on the front, rear, left, and right sides of the vehicle body 1, respectively.A driver's cab 4 is provided above the front wheels 2. Outriggers 5 are fixed to the center and left and right sides of the rear end, respectively. A lifting device 6 is mounted on the upper surface of the vehicle body 1, and a lifting platform 7 is fixed to the upper portion of the lifting device 6, and a handrail 8 is provided around the lifting platform 7.

The lifting device 6 consists of four telescopic booms,
Each telescoping boom has a middle boom 1
0, a lower boom 11, and an upper boom 12. Middle boom 1 for each set of 2
The center of the 0 is connected by a connecting shaft 13 so that it can rotate freely in an X-shape, and the connecting pieces 14 at the tips of each of the lower boom 11 and the upper boom 12 are connected to fixed pieces 16 fixed on the vehicle body 1. and are rotatably connected by a pin. The distance between the fixed pieces 16 and the fixed pieces 17
The intervals between the two are the same, and the vehicle body 1 and the lifting platform 7 are configured to be parallel even when the telescopic boom is extended in an X-shape.

The middle boom 10, which is a set of two, is part 2.
The sets are arranged parallel to each other at intervals, and the middle boom 10 inside each set is connected at the center by an operating shaft 18, so that the axes of the operating shaft 18 and the connecting shaft 13 are in a straight line. It is placed in Both positions close to the fixed piece 16 of the vehicle body 1 and the operating axis 18
Hydraulic expansion and contraction mechanisms 19 are respectively arranged between them, and both hydraulic expansion and contraction mechanisms 19 are arranged to form an isosceles triangle with the operating shaft 18 as the apex.

Next, FIGS. 5 and 6 show the internal structure of the above-mentioned telescopic boom, that is, the middle boom 10,
The middle boom 10 is made by bending a thin steel plate and has a hollow square-shaped cross section in the length direction.
1 is slidably inserted. This lower boom 1
1 has a hollow rectangular cross section made by bending a thin steel plate, and inside this lower boom 11 there is a middle boom 1.
An upper boom 12 inserted from the other open end of 0 is slidably inserted therethrough.

Fan-shaped shaft support pieces 20 and 21 are fixed to both ends of the middle boom 10, respectively, and a pair of guide rollers 22 and 23 are rotatably supported on the shaft support pieces 20 and 21, respectively. The guide rollers 22 are in contact with both sides of the lower boom 11, and the guide rollers 23 are in contact with both sides of the upper boom 12. In addition, a gear box 24 is located at the end of the middle boom 10 that is close to the shaft support piece 21.
is fixed to the gear box 24, and two sprocket wheels 25 and 26 are pivotally supported within the gear box 24.

The tip of the lower boom 11 (the deepest position in the middle boom 10) and the tip of the upper boom 12 are connected by a chain 27.
7 is wound around the outer periphery of the sprocket wheels 25 and 26 in an S-shape. By this chain 27, the extension amount of the lower boom 11 and the upper boom 12 is coordinated, and the middle boom 10
Therefore, the lower boom 11 and the upper boom 12 move in and out by the same amount of expansion and contraction.

Further, FIG. 6 shows a cross section of the center of the middle boom 10, and a band-shaped holder 28 is wrapped around and fixed to the outer periphery of the center of the middle boom 10. A cylindrical connecting shaft 13 is fixed. An engagement piece 30 fixed with a screw 29 is fixed to the other holding body 28.
By fitting the engaging piece 30 into an engaging groove 31 formed on the outer periphery of the connecting shaft 13, the two middle booms 10 are connected in an X-shape and their rotation is maintained freely. A shaft support 32 is protruded from the opposite side of the connecting shaft 13 of the holder 28 of one of the middle booms 10, and the operating shaft 18 is connected to this support shaft 32.

Next, FIG. 7 explains in detail the internal structure of the hydraulic expansion and contraction mechanism 19 which is an embodiment of the present invention.

The hydraulic expansion/contraction mechanism 19 is roughly divided into an internally hollow storage cylinder 41, a hydraulic cylinder 42 inserted into the storage cylinder 41, and a wire 53.

The storage cylinder 41 has a hollow shape with a square-shaped cross section and is open at both ends, and a shaft support 43 that is rotatably supported by the frame of the vehicle body 1 projects from the lower left and right sides. , Wire hooks 44 are fixed to the upper part of the storage cylinder 41 from the left and right toward the center, and upper rollers 45 are attached to the four inner walls of the upper part so as to surround the central axis of the storage cylinder 41. They are arranged and each is supported by a shaft.

The hydraulic cylinder 42 has a single cylinder rod 46 and is of a mechanism that extends in one stage,
A rectangular pedestal 47 is fixed to the base of the hydraulic cylinder 42 , and a lower roller 48 is pivotally supported on each of the four sides of the pedestal 47 . has been brought into contact with. Further, the above-mentioned upper roller 45 is brought into contact with the upper outer periphery of the hydraulic cylinder 42, and the hydraulic cylinder 42 can freely slide in the length direction within the housing cylinder 41 by the upper roller 45 and the lower roller 48. It is maintained so that it can be moved.

The hydraulic cylinder 42 is deviated by 45 degrees from the lower roller 48 on the lower surface of the pedestal 47.
Two pulleys 49 and 50 are each pivotally supported at a pair of positions symmetrical from the central axis.
A connecting metal fitting 51 having a U-shape and connected to the aforementioned operating shaft 18 is fixed to the tip of the aforementioned cylinder rod 46, and wire hooks 52 are made to protrude from the left and right sides of this connecting metal fitting 51, respectively. A wire 53 is hung on each wire hook 52, and each wire 53 is attached to the storage cylinder 4.
1 and the hydraulic cylinder 42 and are stretched toward the base of the hydraulic cylinder 42, and both wires 53 are connected to the pulleys 49, 5.
0 and folded back to the opposite side, and then inserted into the storage cylinder 41 and hooked on the wire hook 44 at each terminal end. As a result, the hydraulic cylinder 42 is suspended within the housing cylinder 41 by the pair of wires 53, and each wire 5
3 will be held in the target position.

8 is a sectional view taken along the line X--X in FIG. 7, and FIG. 9 is a sectional view taken along the line Y--Y in FIG. 7.

Next, FIG. 10 shows the hydraulic circuit in this embodiment.

The hydraulic pump 60 has a suction side connected to the oil tank, a relief valve 62 and a switching valve 63 connected to its discharge side, and a return path of the switching valve 63 communicating with the oil tank 61. Pistons 66 and 67 are slidably inserted into the two hydraulic cylinders 64 and 65 (corresponding to the hydraulic cylinder 42 in FIG. 7 above), respectively. 68 and 69 are connected. This piston 66,
67 divides the inside of the hydraulic cylinders 64 and 65 into respective pressure chambers 70 and 72 and discharge chambers 71 and 73, and the discharge chambers 71 and 72 are in communication with each other. 73 are each connected to a switching valve 63.

When the cross-sectional areas of the pressure chambers 70, 72 and the discharge chamber 71 are shown in _FIG . S ₂ is shown, and C shows the cross-sectional area S ₃ of the pressure chamber 72, which is assumed to be the same as the cross-sectional areas S ₂ and S ₃ .

Next, the operation of this embodiment will be explained.

First, an engine (not shown) attached to the vehicle body 1 is operated, and the engine drives a hydraulic pressure generating mechanism to generate hydraulic pressure, and this hydraulic pressure is transferred to the hydraulic cylinder 4.
2. Therefore, the hydraulic cylinder 42 is extended in its length direction, the cylinder rod 46 is operated to protrude from the hydraulic cylinder 42, and the distance between the pedestal 47 and the connecting fitting 51 is changed to become larger. For this reason, wire hooks 44 and 52
The wire 53 stretched between the
The distance between the wire hook 52 and the pulleys 49, 50 becomes longer. Since the length of the wire 53 itself is constant and does not expand under load, the length of the wire 53 between the wire hook 44 and the pulleys 49, 50 is relatively shortened. The hydraulic cylinder 42 protrudes from the upper opening of the housing cylinder 41. This hydraulic cylinder 42
The movement within the storage cylinder 41 is carried out by the cylinder rod 46.
According to the amount of extension, the distance between the connecting fitting 51 and the base of the storage cylinder 41 is the sum of the amount by which the cylinder rod 46 extends from the hydraulic cylinder 42 and the amount by which the hydraulic cylinder 42 extends from the storage cylinder 41.
This is approximately twice the amount of expansion of the hydraulic cylinder 42 alone.

When this hydraulic expansion/contraction mechanism 19 operates, the connecting fitting 51
When the middle boom 10 is protruded from the storage cylinder 41,
is lifted upward, and the lower boom 11 and upper boom 12 are pulled out from the middle boom 10. However, since the lower boom 11 and the upper boom 12 are connected by a chain 27, the lower boom 11 and the upper boom 12 are pulled out from the middle boom 10. 11 comes out from the middle boom 10, the chain 2 fixed to the tip of the lower boom 11
7 moves while rotating the sprocket wheels 25 and 26, and as the chain 27 moves, the lower end of the upper boom 12 is pulled, and the upper boom 12 is pulled out from the upper end opening of the middle boom 10. Moreover, since the chain 27 does not extend, the amount of extension of the lower boom 11 and the upper boom 12 is the same. The lifting platform 7 is lifted by rotating around the connecting shaft 13 in an X-shape. Therefore, the lifting platform 7 rises horizontally, and the rising height is determined by the amount of extension of the hydraulic expansion mechanism 19.
Since the amount of extension of the connecting fitting 51, that is, the cylinder rod 46, is doubled, the maximum lifting height of the lifting platform 7 can be increased.

Next, the relationship between the lifting mechanism 6 and the hydraulic expansion/contraction mechanism 19 will be explained with reference to FIG. When the switching valve 63 is switched, the operating shaft is injected into the pressure chamber 70, and the piston 66,
Push the cylinder rod 68 upwards. As this piston 66 slides, the hydraulic oil in the discharge chamber 71 is transmitted to the pressure chamber 72 of the hydraulic cylinder 65, pushing up the piston 67 and cylinder rod 69, and the hydraulic oil in the discharge chamber 73 is transferred to the pressure chamber 72 of the hydraulic cylinder 65. and return it to the oil tank 61.

Here, since the cross-sectional areas of each pressure chamber 70, 72 and discharge chamber 71 have the relationship shown in FIG. It is calculated by multiplying the cross-sectional area excluding the cross-sectional area by its movement length, and by transmitting this discharged hydraulic oil to the pressure chamber 72 with the same cross-sectional area, it becomes the same as the movement amount of the piston 66, and the cylinder rod 68, 69 The extrusion length is the same for both.

As shown in FIG. 3, the hydraulic expansion and contraction mechanisms 19 are arranged in an isosceles triangle shape with the connecting shaft 13 at the center. Therefore, if the amount of expansion of both cylinder rods 68 and 69 is the same, It always rises in a direction perpendicular to the vehicle body 1. Since the extrusion amounts of the lower boom 11 and upper boom 12 inserted into each middle boom 10 are synchronous and the same, the extrusion amounts of all lower booms and upper booms 12 are all the same, and the lifting platform 7 is It will rise parallel to and perpendicular to it. To explain the relationship between the amounts of movement with reference to FIG.
3 is raised in a straight line, and the lower boom 1
1. The extrusion amount Z of the upper boom 12 is the same, and the movement amounts of all the booms 11 and 12 are synchronized.

〔effect〕

Since the present invention is configured as described above, compared to the conventional pantograph type link mechanism, there is no need to stack multiple sets of link mechanisms vertically in order to increase the limit of the height that can be raised and lowered by the lifting platform, and the height that can be raised can be increased. You can increase the limit. For this reason, the height from the ground to the lifting platform when it is in the reduced and folded state can be made smaller compared to its lifting capacity, and when moving the lifting device, it will not come into contact with other structures, etc. It is possible to prevent problems such as In addition, since the telescoping mechanism is arranged in a V-shape to lift the telescoping boom, there is no need for a kick mechanism for initial operation, and the resultant force of both acts upward and vertically. , the lifting platform can be raised quickly and vertically. Furthermore, the telescoping mechanism is composed of a hydraulic cylinder, a storage cylinder, and a wire, and the entire structure can be expanded and contracted by twice the amount of expansion and contraction of the hydraulic cylinder. Can be raised to a higher position.

[Brief explanation of drawings]

Fig. 1 is an explanatory diagram showing the outline of the newly proposed elevating device, Fig. 2 is a side view showing an embodiment of the elevating device with the elevating device lowered to the lowest position, and Fig. 3 is the same as above. Fig. 4 is a rear view of the state shown in Fig. 3, Fig. 5 is a side sectional view showing the inside of the middle boom, and Fig. 6 is a side view showing the state in which the lifting device is fully extended. FIG. 7 is a partially cutaway perspective view to show the internal structure of the hydraulic expansion and contraction mechanism; FIG. 8 is a cross-sectional view taken along the line X--X in FIG. 7; FIG. 9 is a cross-sectional view of the middle boom; Fig. 7 is a cross-sectional view taken along Y-Y arrows in Fig. 7, Fig. 10 is a piping diagram showing the oil passage of the hydraulic mechanism, Fig. 11 is an explanatory diagram showing the cross-sectional area of each part inside the cylinder, and Fig. 12 is the lifting device and hydraulic expansion/contraction mechanism. FIG. 1... Vehicle body, 6... Lifting device, 7... Lifting platform,
10... Upper boom, 11... Lower boom, 12
...Upper boom, 19...Hydraulic telescoping mechanism, 41...
... Storage cylinder, 42 ... Hydraulic cylinder, 46 ... Cylinder rod, 53 ... Wire, 64, 65 ...
...Hydraulic cylinder.

Claims (1)

[Claims] 1. A movable vehicle body, a lifting platform located above the vehicle body that can be raised and lowered, and a pair of middle booms rotatably supported at the center and combined in an X shape;
A lower boom that moves along the length of each middle boom and whose lower ends are connected to the vehicle body, and an upper boom that moves along the length of each middle boom and whose upper ends are connected to a lifting platform. A lifting device having a boom, a flexible connecting means for connecting a lower boom and an upper boom in each middle boom to regulate the amount of movement of both, and a flexible connecting means provided on the middle boom and in a moving direction of the connecting means. and a pair of telescoping mechanisms disposed in a V-shape between two spaced apart positions on the vehicle body and the middle boom to vertically lift the platform. In the elevating device, both of the telescoping mechanisms include: a storage cylinder having a longitudinal opening and whose lower end is swingably connected to the vehicle body; A hydraulic cylinder is movably inserted, its upper end is swingably connected to the center of rotation of the middle boom, and the cylinder rod can be extended and contracted along the length of the storage cylinder; a wire connected near the opening of the body, the other end connected to the cylinder rod of the hydraulic cylinder, the middle part of which is routed inside the housing cylinder and brought into contact with the base of the hydraulic cylinder, and the hydraulic cylinder extends. As a result, the wire is pulled out from the housing cylinder, and by pulling out the wire, the hydraulic cylinder itself is also pulled out from the housing cylinder, and the distance between the lower end of the housing cylinder and the tip of the cylinder rod becomes approximately twice the amount of extension of the hydraulic cylinder. A lifting device characterized by operating as follows.