JP2563999Y2 - Multi-stage telescopic boom - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial application field) The present invention relates to a multi-stage telescopic boom, particularly to a multi-stage telescopic boom whose base is pivotally mounted on a swivel or the like of a crane truck. (Prior art) Conventional multi-stage telescopic booms, especially multi-stage telescopic booms whose base is pivotally mounted on a swivel or the like of a crane truck, include:
For example, there is one as shown in FIG. This has a telescope-shaped inner, inner and innermost booms 30, 40 and 50 of substantially similar cross-section inside an outer boom 20 whose base is mounted on a swivel or the like of a crane truck (not shown). The cylinder body 22 of the hydraulic cylinder 21 and the base of the piston rod 24 are mounted on the shafts 23 and 25, respectively, between the bases of the outer boom 20 and the inner boom 30. The other ends of the first and second elongate ropes 27, 36 attached to the ends of the first and second booms 30, 40 via the tensioning devices 29, 37 via sheaves 26, 39 at the ends of the inner and inner booms 30, 40. , Inward and innermost boom 40,
The other end of the first and second contraction ropes 31, 41 attached to the base of the inner and innermost booms 40, 50 with the other end attached to the base of the inner and inner booms. 30, 40
Through the base sheaves 33, 44, the outer and inner boom 20,
It is attached to the end of 30 and is attached to the left and right sides of the cylinder body 22 of the hydraulic cylinder 21 and is discharged from the other side, so that it is inside and inside the outside boom 20. The innermost booms 30, 40, and 50 are simultaneously extended and contracted at the same time, and the rope P hanging from the sheave at the end of the innermost boom 50 is wound up by a winch (not shown) and unwound, thereby unloading the load W. To do the operation. The extension ropes 27 and 36 of the telescopic boom in this conventional device were inserted between the side walls of adjacent booms as shown in FIG. Also, the inner, inner and innermost booms 30, 40 and
It is also known that a hydraulic cylinder is provided between 50 cylinders. Further, Japanese Unexamined Patent Publication No. 55-98087 discloses that the upper boom device adjacent to the lower boom device, that is, the intermediate boom is moved relative to the lower boom device by a flexible device wrapped around the lower boom device that expands and contracts. A flexible body device that expands and contracts and is hung around the middle stage boom, and an adjacent boom device on the upper stage side,
That is, a play gap on the stroke and a detachable locking mechanism are provided between the upper boom and the intermediate boom, and after the intermediate boom progresses the play step, the flexible device and the upper boom are locked, and the upper boom is moved. In addition to starting to extend, when the boom is extended or contracted, the upper stage boom is configured to release the locking mechanism by a near-end stroke operation to complete the contraction to the intermediate stage boom. A multi-stage telescopic boom is described that is capable of performing cargo handling operations of different capacities. Japanese Patent Laid-Open No. 55-106990 discloses that a cylinder is disposed between any two of an outer cylinder, a middle cylinder, and an inner cylinder which are slidably inserted with each other, and a tip of the middle cylinder is provided. A guide wheel is pivotally attached to the portion and the base tube portion, and first and second cables are fixed at one end to the inside of the upper portion of the inner cylinder base, and the first cable is provided at the tip of the middle cylinder. The guide wheel is hung, the other end is hung on the guide means on the base end side of the middle cylinder, and the other end is hung on the operation means of the base end of the base cylinder, and the other end is held on the holding means on the upper outer side of the middle cylinder. The operation means is fixed to the base of the outer cylinder or a base or a base of the middle cylinder so as to be selectively engageable with the holding means, and the holding means is moved relative to the middle cylinder of the stopper provided at the tip of the inner cylinder. Describes a boom extension device of a crane truck provided so as to be selectively engageable with a tip of an outer cylinder or a tip of a middle cylinder. (Problems to be Solved by the Invention) However, in the conventional multi-stage (four-stage) telescopic boom as shown in FIG. 5, the rope P hanging down through the sheave at the end of the innermost boom 50 is required. When the load W is wound and unwound by a not-shown winch and the load W is operated in the lengthwise direction of the boom, a compressive force is generated on the innermost boom 50 by the load W. Now, assuming that a component force of the compressive force in the length direction of the innermost boom 50 is F, a reaction force (tensile force) is applied to the second extension rope 36 in order to support the component force F to the innermost boom 50. Force) F is generated, 2F is generated in the inner side boom 40 which supports the second extension rope 36 via the seaboo 39, and the first extension rope 27 is opposed to the first extension rope 27 to support 2F of the inner side boom 40. Reaction force 2F
Occurs. Thus, the first extension rope 27 is connected to the second extension rope 36.
Therefore, it is necessary to make the thickness sufficiently thicker than the second extension rope 36 or to increase the number thereof.
Since it is necessary to make the space between the inside of the inner boom 30 provided with the first extension rope 27 and the outside of the inner boom 40 sufficiently large, the cross-sectional area of the inner and innermost booms 40 and 50 is reduced. Or, the cross-sectional area of the inner and outer booms 30, 20 must be increased, and in the former, the strength of the inner and innermost booms 40, 50 is reduced, that is, the cross-sectional area of the distal boom is relatively small. There is a risk of causing a sharp decrease and significantly impairing the strength, and in the latter, the weight of the outer and inner booms 20 and 30 increases more than necessary, so that the weight increases,
Further, if the distance between the inner boom 30 and the inner side boom 40 increases, it becomes necessary to provide a thicker slide plate between the two booms, which leads to an increase in weight due to the installation of the same thickness slide plate, and consequently a lifting load. However, there is a problem that a relative decrease is caused. In addition, apart from the tensile force F corresponding to the compressive force F generated on the innermost boom 50 by the load W, the rope P and the innermost boom 50 And the weight of the inner boom 40, the first and second extension ropes
The weight of the innermost and innermost booms 50, 40 reaching 8 to 10 U.M. is added to the first extension rope 27, especially the weight of the first and second contraction ropes 31,41. Therefore, there is a problem that a strength capable of supporting a load larger than that of the 2F is required, and the above tendency is further increased. Further, in the case where the hydraulic cylinders are provided between the inner side, the inner side, and the innermost booms 30, 40, 50, respectively, the compressive force generated in each of the booms 40, 30 by the load W only,
Although it is possible to use only the pulling force F described above, a heavy hydraulic cylinder is provided between the inner, inner and innermost booms 30, 40, and 50, so that the telescopic boom, especially when it is extended, In addition to the decrease in the stability of the boom, the weight of the telescopic boom increases, so the hanging load decreases, and the piping structure becomes long and complicated, and
Since it is necessary to increase the cross-sectional area of the telescopic boom so that a plurality of hydraulic cylinders can be housed therein, there is a problem that the weight of the telescopic boom is increased. Further, in the device described in Japanese Patent Application Laid-Open No. 55-98087, an intermediate stage boom expands and contracts with respect to a lower stage boom device, and a flexible body device hung around the intermediate stage boom,
Further, a gap on the stroke and a detachable locking mechanism are provided between the adjacent boom device on the upper stage, that is, the upper stage boom, and after the intermediate stage boom advances in the clearance step, the flexible device and the upper stage are moved. After the boom is locked, the upper boom is started to extend, and when the boom is extended or contracted, the locking mechanism is released by a stroke operation near the time when the upper boom completes the contraction to the intermediate boom. With this configuration, the load capacity varies depending on the expansion / contraction stages, so that the flexible body device wrapped around the intermediate boom and the adjacent boom device on the upper stage side (upper boom)
It is necessary to provide a play gap on the stroke and a detachable locking mechanism between them, which not only complicates the structure, but also causes the upper boom to extend after the middle boom play step progresses. There is a problem that the amount of extension of the telescopic boom is reduced by the play space. Further, in the boom expansion and contraction device described in Japanese Patent Application Laid-Open No. 55-106990, an outer cylinder, a middle cylinder, and a single hydraulic cylinder and first and second cords (extension and contraction ropes) are used. The first operation of extending and contracting the inner cylinder while performing the expansion and contraction operation of the inner cylinder
The advantage of being able to reduce the gap between the inner cylinder and the middle cylinder is to reduce the gap between the inner cylinder and the middle cylinder because the cable is stretched inside the inner cylinder without disposing it between the inner cylinder and the middle cylinder. However, in this case, the bearing portion for mounting the hydraulic cylinder to the cylinder base of the cylinder main body is provided on the upper side inside the middle cylinder base. No consideration is given to supporting any intermediate portion of the two ropes, and therefore, a receiving member for preventing or reducing the generation of large waving of the thick and long first ropes in the extension and contraction process of the extension boom. There is no means, and eventually it collides against the lower inner wall of the inner cylinder, etc., and generates a loud impact noise. To prevent or reduce the generation of the noise, a space is required between the hydraulic cylinder and the lower inner wall of the inner cylinder. Need to be secured, and thus outside There is a problem that the not serve as lead to an increase in the outer diameter. In particular, in a multi-stage telescopic boom having two hydraulic cylinders, the first hydraulic cylinder is disposed above the second hydraulic cylinder, so that the distance between the upper side of the second hydraulic cylinder and the inner upper surface of the telescopic boom is increased. In the case of a multi-stage telescopic boom in which a large-diameter first extension rope is provided, and a large-diameter first extension rope is used for handling a heavy load with a long stroke, the floating range of the first extension rope is wide. As a result, the vertical movement range of the first extension rope is widened, which may cause a more intense vertical impact force. In addition, the long first and second hydraulic cylinders may cause the long expansion and contraction. There is a problem that the range of fluctuation in the cylinder is widened. In view of the above-described problems of the conventional example, the present invention relates to the base of the piston rod of the first hydraulic cylinder and the base of the cylinder main body which are disposed on the upper inside of the innermost boom of the rectangular tubular telescopic boom. Axial mounting on the side walls of the outermost boom base and the outer boom base, respectively, and the base of the piston rod of the second hydraulic cylinder disposed below the first hydraulic cylinder and the base of the hydraulic cylinder body, While being axially attached to the base of the outer boom and the side wall of the base of the inner boom, respectively, the inner and innermost booms arranged inside the inner boom are attached via two sets of right and left telescopic ropes. A first extension rope for extending the inner side boom mounted adjacent to the inner boom is provided at right and left ends of a cylinder body of the second hydraulic cylinder disposed inside the innermost boom. A guide member at the end of the cylinder body of the first hydraulic cylinder, and a guide member at the end of the cylinder body of the second hydraulic cylinder. The first and second hydraulic cylinders are provided in the telescopic boom, and the multi-stage telescopic boom capable of performing a heavy load and high lift cargo handling operation is provided without the above-mentioned problem. It is something to offer. (Means for Solving the Problems) In order to solve the problems of the conventional example as described above, the present invention is to solve the problem of the conventional example by using the base of the outermost boom having a rectangular tube shape and the outer side of the rectangular tube adjacent to the outermost boom. The piston rod base of the first hydraulic cylinder and the first hydraulic cylinder body base, which are disposed on the upper part of the inner central part of the innermost boom, are mounted on the boom base by bearings on the upper parts of their side walls, respectively. 1
A guide member of the first hydraulic cylinder is provided from an end of the cylinder body of the hydraulic cylinder to an upper side of the telescopic boom and an upper side of a second hydraulic cylinder described later, and is provided adjacent to the outer boom base and the outer boom. A square-rod inner boom base, a piston rod base of a second hydraulic cylinder disposed below the inner central part of the innermost boom, and a cylinder body base of the second hydraulic cylinder are respectively formed by bearings. At the lower part of the side wall, the second
The extension projecting from the end of the hydraulic cylinder body has the second
A guide member is provided under and above the hydraulic cylinder, on both left and right sides, and a first extension rope attached to a lower portion on the inner left and right sides of the inner boom base adjacent to the inner boom is connected to an end of a cylinder body of the second hydraulic cylinder. Through the sheaves on both left and right sides of the section, between the upper left and right sides of the cylinder body and the upper left and right sides of the innermost boom, and attach the end to the upper left and right sides of the outer boom base; Through the outer side of the innermost boom and the inner side of the inner boom, and through a pair of sheaves provided at the upper left and right sides of the inner boom end. The first shrink rope with the base end attached to the lower left and right sides of the inner boom base, while the first end is attached to the upper left and right sides outside the inner boom end. And through the sieve, through between the inner right and left side lower outer right and left side lower and outer boom of the inner boom,
A second contraction rope having its end attached to the lower left and right inner sides of the outer boom end and the lower end attached to the lower left and right inner sides of the innermost boom base is provided at the lower left and right both sides of the inner boom base. A multi-stage telescopic boom having an end attached to the inner left and right lower sides of the inner boom end through a space between the outer left and right lower sides of the inner boom and the inner left and right lower sides of the inner boom via a sheave. (Operation) Since the present invention has the above-described configuration, the first,
By expanding and contracting the second hydraulic cylinder, it is possible to expand and contract the outer boom and the inner boom disposed adjacent to the innermost and outermost booms and the outer boom in the shape of a rectangular cylinder, and to expand and contract the inner boom. Of the inner boom and the inner boom, the inner boom and the innermost boom through a pair of left and right first extension ropes, a first contraction rope, a second extension rope, and a second contraction rope, respectively. Each of the booms expands and contracts in the same length as the inner boom, and in a step of extending the telescopic boom, a central portion of an upper span of the first extension rope is
By the bearings on both left and right sides of the second hydraulic cylinder body base, it is received on the side wall of the inner boom base,
Therefore, in the middle of expansion and contraction of the telescopic boom and in the extended state, a space for disposing the first hydraulic cylinder is required over a long span of the thick first extension rope and above the second hydraulic cylinder. Excessive impact force due to the vertical movement of the first extension rope having a large diameter, which is to be generated at a wide space between the upper side of the cylinder and the inner upper surface of the innermost boom, is generated on both the left and right sides of the second hydraulic cylinder body base. It is absorbed by the bearing portion and is not added to the bearing portion or the like of the sheave of the first contraction rope, and the guide member at the end of the cylinder body of the first hydraulic cylinder, the second
By providing the guide member at the end of the cylinder body of the hydraulic cylinder at the extension from the respective tops,
2 The hydraulic cylinder is guided to expand and contract smoothly. (Example) Hereinafter, one example (5) of the multistage telescopic boom according to the present invention will be described.
The step extendable boom will be described with reference to FIGS. Note that the same parts as those of the conventional example shown in FIG. In FIGS. 1 to 4, reference numeral 10 denotes a first boom having a rectangular cylindrical shape whose base is rotatably mounted on a swivel or the like of a crane truck (not shown), 20, 30, 40, and 50 correspond to the first boom 10; The second boom, the third boom, the fourth boom, the fifth boom, which are substantially similar in shape, and are inserted in the first boom 10 so as to be slidable sequentially.
Reference numeral 12 denotes a first hydraulic cylinder provided between the base of the first boom 10 and the base of the second boom 20. The base of the cylinder body 13 of the first hydraulic cylinder 12 is mounted on the shaft 14 at the base of the second boom 20, and its piston The base of the rod 15 is mounted on the shaft 17 of the base of the first boom 10. Reference numeral 16 denotes an extension of the end (exceeding the top) of the cylinder body 13 of the first hydraulic cylinder 12, and 16A and 16B denote guide members provided above and below the extension 16. In this embodiment, the first boom 10, the second boom 20, the third boom 30, the fourth boom
40 and the fifth boom 50 correspond to the outermost boom, the outer boom, the inner boom, the inner boom and the innermost boom of the present invention. Reference numeral 21 denotes a second hydraulic cylinder provided between the second boom 20 and the third boom 30. The base of the cylinder body 22 is provided at the base of the third boom 30, and the base of the piston rod 24 is provided at the base of the second boom 20. , 25. 26 is the second hydraulic cylinder 21
Sheaves 22C, 22D, and 22E which are mounted on the mounting plate 22B on the extension 22A at the end of the cylinder body 22 are guide rollers provided on the lower portion, the upper portion, and both side portions of the mounting plate 22B, and these guide rollers 22C, 22D and 22E are provided so as to face the inside of both the vertical and horizontal walls of the telescopic boom. Reference numerals 27, 27 denote a pair of left and right first extension ropes. One end of each of the first extension ropes 27, 27 is attached to the inside lower part of the base of the fourth (inwardly) boom 40, and the other end is the sheave. 26 to the base side of the second (outer) boom 20 and a tensioning device 29
Attached to the inside upper part of the base of the second boom 20 via. Reference numerals 31 and 31 denote a pair of left and right first contraction ropes, one ends of which are attached to the lower inside of the end of the second boom 20 via tensioning devices 32 and 32, and the other ends of which are the second boom 20 and the third boom 30. Through the hole (not shown) in the base of the third boom 30 and through the sheave 33 mounted on the base of the side wall of the third boom, to the inside of the base of the fourth (inwardly) boom 40. Mounted 34, 34 at the bottom. 35 and 35A are covers around the sheave 33, and the engagement between the first contraction rope 31 and the sheave 33 is ensured by the covers 35 and 35A. 36 and 36 are a pair of left and right second extension ropes, 37 and 37 are tension devices for attaching one end of the second extension rope 36 to the upper outside of the end of the third boom 30, and 38 and 38 are second extension ropes 36 and 36. The other end is a mounting portion that is mounted on the outer upper portion of the base of the fifth boom 50 via the sheaves 39, 39 at the end of the fourth boom 40. Reference numerals 41, 41 denote a pair of left and right second contraction ropes. One end of each of the second contraction ropes 41, 41 is attached to the lower end inside the end of the third boom 30 via a tensioning device 42, 42. 4th
Pass through the bottom wall between the boom 40 and the hole 4 at the base of the fourth boom 40
It is led out from 3, 43 to the inside, and is attached 45, 45 to the lower outside of the base of the fifth boom 50 via sheaves 44, 44 at the base of the fourth boom 40. 46 and 46A are covers around the sheaves 44 and 44, and the covers 46 and 46A are used to cover the second contraction ropes 41 and 41.
And the sheaves 44, 44 are secured with each other. (Operation of the Embodiment) First, by sending pressure oil to the base side of the cylinder body 13 of the first hydraulic cylinder 12 and discharging the pressure oil at the end side, the second boom 20 is moved relative to the first boom 10. Is extended to the left (FIG. 2 shows the first hydraulic cylinder 12 in a fully extended state, with the central portion of the first boom 10 and the piston rod 15 cut away). Cylinder body
Send pressure oil to the base side of 22, drain the pressure oil from the end side,
The third boom 30 is extended to the left with respect to the second boom 20. FIG. 2 shows a state where the cylinder body 22 of the second hydraulic cylinder 21 is extended by about a quarter of a stroke. With the extension of the third boom 30 to the left (FIG. 2),
A middle portion of the first extension ropes 27, 27, one end of which is attached to the inner base of the second boom 20 by the tensioning devices 29, 29, is a sheave supported on a mounting plate 22B on an extension 22A of the cylinder body 22.
The fourth boom 40, which is pushed to the left by 26, 26 and attaches the end of the first extension rope 27, 27 to the base, extends to the left, and at the same time, the sheave 39 at the end of the fourth boom 40. , 39 push the middle portion of the second extension ropes 36, 36 to the left, causing the fifth boom 50 to extend to the left. Next, in order to contract the five-stage telescopic boom in the extended state as described above, first, pressurized oil is sent to the right side (FIG. 2) of the cylinder body 22 of the second hydraulic cylinder 21 so that the second hydraulic cylinder 21 When the third boom 30 is contracted with respect to the second boom 20, one end is at the end of the second boom 20 and the other end is at the fourth end.
The first shrink rope 31 attached to the base of the boom 40 32, 34,
The middle part of 31 is pulled to the right by sheaves 33, 33 at the base of the third boom 30, and the fourth boom 40 is retracted to the right and contracted. The middle part of the second contraction ropes 41, 41 attached to the end of the third boom 30 is pulled rightward by the sheaves 44, 44 at the base of the fourth boom 40, and the other ends of the second contraction ropes 21, 21 The fifth boom 50 attached to the base is retracted to the right and contracted to the state shown in FIG. Note that the fourth boom 40 and the fifth boom 50 of this embodiment
Is extended and contracted with respect to the boom 30 at the same time as the extension and contraction of the third boom 30 due to the extension and contraction of the second hydraulic cylinder 21. Also,
The first and second hydraulic cylinders 12 and 21 of this embodiment can be operated simultaneously or separately. Further, in the present invention, the base of the cylinder body 22 of the second hydraulic cylinder 21 is supported on both side walls of the base of the third (inner) boom 30 and the base ends 34, 34 are connected to the fourth boom 30 by the fourth.
Sheaves 33, 33 for attaching first shrinkage ropes 31, 31, which are attached to the base of the (inside) boom 40 and whose ends 32, 32 are attached to the inside lower part of the end of the second (outer) boom 20, The third
The (inside) boom 30 may be embodied as a multistage telescopic boom disposed below the bearing 23 of the cylinder body 22 at the base. (Effects of the Invention) Since the invention has the above-described configuration and operates, the following effects can be obtained. (1) First and second telescopic booms, two-stage telescopic booms arranged on the inner right and left sides of the inner boom of the same cross-sectional shape that are expanded and contracted by the second hydraulic cylinder with respect to the outer cylindrical boom.
A second pair of hydraulic cylinders, in which a pair of left and right first extension ropes for extending the inner boom adjacent to the inner boom are arranged inside the innermost boom when being mounted via two sets of telescopic ropes. Because it is stretched via sheaves on both the left and right sides of the end of the main body, and the pair of left and right first extension ropes is disposed between the upper left and right inner sides of the innermost boom and the upper left and right sides of the second hydraulic cylinder. Therefore, the distance between the inner boom and the inner side boom can be made narrower than in the conventional example, and thus the pair of left and right first extension ropes can be heavily loaded without increasing the cross-sectional area of the inner boom as compared with the same conventional example. It is easy to configure as a thing or number of pieces that can be used for cargo handling, and the degree of freedom of disposing the first hydraulic cylinder above the second hydraulic cylinder provided between the outermost boom and the outer boom is improved. And multi-stage telescopic As the degree of freedom in designing the ones for large load of the left and right first elongated rope in arm is improved. (2) Since the first extension rope is disposed inside the innermost boom without being disposed between the inner boom and the inner side boom, the interval between the both booms can be made narrower than in the conventional example. As a result, abrupt change in the cross-sectional area of the adjacent boom in the multi-stage telescopic boom is prevented, and it becomes easy to provide a multi-stage telescopic boom having a higher strength and a longer telescopic stroke than conventional multi-stage telescopic booms of the same type. (3) Without expanding and contracting the innermost boom and the innermost boom of the square tubular multistage telescopic boom with the hydraulic cylinder,
By using a telescopic structure connected by an extension rope and a contraction rope arranged on both the left and right sides, long pipes for supplying and discharging hydraulic oil to and from the hydraulic cylinder are provided, as in the conventional case where a hydraulic cylinder is provided in the same part as in the conventional example. There is no need to provide it, and the structure is simplified, and the weight of the multi-stage telescopic boom is lighter than that of the conventional example of the same type, and the stable operability of special vehicles equipped with this telescopic boom is improved and the maximum lifting capacity is improved Can be achieved. (4) Since the base of the cylinder main body of the second hydraulic cylinder is to be supported at substantially the center in the vertical direction of both side walls of the inner boom base, the base end is attached to the inside of the base of the inner boom and the end Attached to the outside of the base of the end of the outer boom
A sheave for stretching the contraction rope can be provided at the lower portion inside the base of the inner boom, below the bearing portion of the cylinder body base of the second hydraulic cylinder. In the middle extension area other than the maximum extension or minimum contraction area, even if a large-diameter first extension rope has a large amplitude undulation, the downward undulation is generated on both sides of the second hydraulic cylinder main body base. It is supported and absorbed by bearings on both side walls of the boom base, and transmission of a large impact force to the sheave or the like is prevented, so that the sheave or the like is effectively protected. (5) Further, the sheave for tension of the first contraction rope is protected from waving downward of the first extension rope,
Since the free span below the first extension rope becomes shorter in accordance with the amount of movement of the bearing portion of the second hydraulic cylinder, that is, the degree of extension of the inner boom, the amplitude of the downward waving decreases correspondingly. In addition, the tensioning sheave of the second contraction rope, which is suspended at a lower position inside the inner side boom, is effectively protected from being hit by the downward waving of the first extension rope. (6) A guide member of the first hydraulic cylinder is provided from an end of the cylinder main body of the first hydraulic cylinder to an upper side of the telescopic boom and an upper side of a second hydraulic cylinder to be described later. Since the extension members protruding from the end portions are provided with guide members on the upper, lower, left and right sides of the second hydraulic cylinder, the degree of freedom in designing the long first and second hydraulic cylinders and, consequently, the multistage telescopic boom having a large stroke is improved. In addition, the telescopic boom can be extended and retracted, and the first and second hydraulic cylinders can be smoothly extended and retracted in the telescopic boom, and the cargo handling operation by the multistage telescopic boom can be performed more smoothly. The assembling operability of the multi-stage telescopic cylinder including the hydraulic cylinder and the second hydraulic cylinder can be improved.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 to FIG. 4 show an embodiment of a multi-stage telescopic boom according to the present invention, and FIG. FIG. 2 is a side view showing the cut-out and partly longitudinal section, and FIG. 2 is an explanatory view of the operation, in which the first hydraulic cylinder is sufficiently extended and the piston rod of the second hydraulic cylinder is extended by about a quarter of a stroke. In this state, a part of the first and fifth booms is cut away and shown.
3 and 4 are sectional views taken along lines III-III and IV-IV in FIG. 1, and FIG. 5 is an explanatory view of a conventional four-stage telescopic boom. (Explanation of Signs) 10 First (outermost) boom 11… Shaft 12… First hydraulic cylinder 13… Cylinder main body 14, 17… Bearing part 15… Piston (of first hydraulic cylinder 12) Extension part 16A of rod 16 (cylinder main body 13) (upper) guide member 16B (lower) guide member 20 second (outer) boom 21 second hydraulic cylinder 22 (second Cylinder body 22A (of hydraulic cylinder 21) ... Extension part 22B (of cylinder body 22) ... Mounting plates 22C, 22D, 22E ... Guide rollers 23, 25 ... Bearing part 24 ... (of second hydraulic cylinder 21) Piston rods 26, 33, 39, 44 Sheave 27 First extension rope 28 Attachment (end of first extension rope 27) 29 Tensioning device 30 Third (inner) boom 31 First contraction rope 35, 35A Cover 36 Second extension rope 37 Tension device 38 Attachment part 40 Fourth (inward) boom 41 Second contraction row 42 ...... tensioning device 43 ...... hole 45 ...... mounting portion 46, 46A ...... cover 50 ...... 5 (innermost) boom

Claims (1)

(57) [Rules for requesting registration of utility model] A piston rod base of a first hydraulic cylinder disposed above an inner central portion of the innermost boom, at a base of the outermost boom having a rectangular cylindrical shape and at a base portion of the outer boom having a rectangular shape adjacent to the outermost boom; The first hydraulic cylinder body base is attached to the upper side of the side wall portion by a bearing portion, and the upper side of the telescopic boom and the upper side of a second hydraulic cylinder described later are opposed from the cylinder body end of the first hydraulic cylinder. A guide member for the first hydraulic cylinder is provided, and a second hydraulic cylinder disposed below the inner central portion of the innermost boom at the outer boom base and the rectangular tubular inner boom base adjacent to the outer boom. A piston rod base,
The cylinder body base of the second hydraulic cylinder is attached to the lower part of the side wall portion by a bearing, and an extension protruding from the end of the second hydraulic cylinder body is located above, below, on the left and right of the second hydraulic cylinder. And a first extension rope attached to the lower part on the left and right side inside the inner boom base adjacent to the inner boom via a sheave on the left and right sides of the end of the cylinder body of the second hydraulic cylinder. Then, pass between the upper left and right sides of the cylinder body and the upper left and right sides of the innermost boom, and attach the end to the upper left and right sides of the outer boom base, and attach the base end to the outer left and right sides of the innermost boom base. Pass the second extension rope attached to the upper side on both sides through the outside of the innermost boom and the inside of the inner side boom, and through a pair of sheaves provided on the left and right upper sides of the inner boom end, A first contraction rope attached to the inner left and right lower sides of the inner side boom base while the base end is attached to the upper left and right upper sides of the outer side of the boom end, via a sheave provided at the lower left and right sides of the inner boom base, Pass the space between the outer left and right lower sides of the inner boom and the inner left and right lower sides of the outer boom and attach the ends to the inner left and right lower sides of the outer boom end, and attach the base end to the inner left and right sides of the innermost boom base. A second contraction rope attached to the lower part is passed through sheaves provided on the lower left and right sides of the base of the inner boom, between the lower left and right lower sides of the inner boom and the lower left and right inner sides of the inner boom. The multi-stage telescopic boom is characterized in that the parts are attached to the lower part on both the inner left and right sides of the end of the inner boom.