WO2011067856A1

WO2011067856A1 - Working vehicle

Info

Publication number: WO2011067856A1
Application number: PCT/JP2009/070417
Authority: WO
Inventors: 博青山; 貴彦澤田
Original assignee: 株式会社日立製作所
Priority date: 2009-12-04
Filing date: 2009-12-04
Publication date: 2011-06-09
Also published as: KR101357956B1; KR20120046228A; JP5318224B2; CN102471041A; CN102471041B; JPWO2011067856A1

Abstract

A working vehicle comprising a translational extension and retraction mechanism which is configured of working booms (7, 8) combined in a nested configuration. The working vehicle is provided with: rollers (1) which are disposed at the overlap portion (17) between the two working booms (7, 8) which extend and retract relative to each other in a translational manner, the rollers (1) sliding on one of the two working booms (7, 8); and a pad (3) which is provided at the overlap portion (17) between the two working booms (7, 8) and which makes contact with said working boom only when a load having a magnitude greater than or equal to a predetermined level acts on the rollers (1). The configuration enables the working boom to be supported by both the pad (3) and the rollers (1) when a high load is applied, and thus, the working vehicle having the translational extension and retraction mechanism which is lightweight and does not deform even under the high load is provided.

Description

Work vehicle

The present invention relates to a work vehicle having a translational expansion / contraction mechanism.

A work vehicle provided with a translational telescopic mechanism configured to extend and contract by translating a plurality of long structures (work booms and ladders) combined in a nested manner includes a crane vehicle, an aerial work vehicle, There are firefighting ladder cars. In this type of work vehicle, work is performed by appropriately expanding and contracting the work device according to the work radius, but in order to smoothly perform the expansion and contraction operation of the work device, sliding of two long structures that translate and extend relative to each other is performed. It is necessary to consider sex.

As a technique relating to this point, there is a technique in which a plurality of rollers are arranged and slid between two ladder portions that are translated and expanded in parallel with each other (see JP-A-11-159269). ).

JP 11-159269 A

In addition to the above slidability, the working device having the translational expansion / contraction mechanism as described above has a load resistance that allows a heavy object to be hung at the tip or the working radius can be increased, and the weight of the device can be reduced. Is required. In general, in order to reduce weight while maintaining load resistance, a method of suppressing the plate thickness of a member by replacing with a material having high strength is often used. The same applies to the reduction of the weight of the work boom of the work vehicle and the ladder of the fire-fighting ladder vehicle, and it is common to design the plate so as not to cause a problem in strength while suppressing the plate thickness. However, there are the following problems in reducing the weight of the working device in a working vehicle having the sliding portion as described above.

When a plurality of rollers are arranged between two ladder parts (work booms) as in the above technique, if a large load is applied to the tip of the work device, a local compressive force acts through the rollers and the ladder part. There is a risk of dent deformation. At this time, even if the working device is slid through three or more rollers to disperse the local compressive force, if a large load is applied so that the working device bends upward, Since the two rollers positioned at the foremost part and the last part come into strong contact with the ladder portion in preference to the other rollers, the effect of load distribution cannot be expected so much. Therefore, in order to prevent the dent deformation by the roller, it is necessary to increase the plate thickness of the member, and as a result, the total weight of the apparatus cannot often be reduced so much.

An object of the present invention is to provide a work vehicle having a lightweight translational expansion / contraction mechanism that can withstand a heavy load.

In order to achieve the above object, according to the present invention, in a work vehicle having a translational expansion / contraction mechanism constituted by a plurality of elongated structures combined in a nested manner, a portion in which two elongated structures that translate and extend each other overlap each other. A first sliding member that slides on one of the two long structures, and a portion where the two long structures overlap, the first sliding member And a second sliding member that comes into contact with the one long structure for the first time when a load of a predetermined size or more is applied thereto.

According to the present invention, it is possible to provide a lightweight translational expansion / contraction mechanism that does not deform even when a heavy load is applied.

The perspective view of the crane vehicle which concerns on embodiment of this invention. The enlarged view of the overlap part of the two work booms in the crane vehicle of FIG. The perspective view of the sliding structure which concerns on the 1st Embodiment of this invention. The cross-sectional view of the sliding structure fixed to the front-end | tip of a work boom in the 1st Embodiment of this invention. The cross-sectional view of a sliding structure when the load more than predetermined magnitude | size acts on the roller in the 1st Embodiment of this invention. The perspective view of the pad which concerns on the 2nd Embodiment of this invention. The perspective view of the pad which concerns on the modification of the 2nd Embodiment of this invention. The figure which shows the friction coefficient change of a fiber reinforced composite material and a metal. The perspective view of a sliding structure provided with the pad which concerns on the 3rd Embodiment of this invention. The perspective view of the sliding structure which concerns on the 4th Embodiment of this invention. The perspective view of the sliding structure which concerns on the modification of the 4th Embodiment of this invention. The cross-sectional view of the sliding structure which concerns on the 5th Embodiment of this invention. The perspective view of the sliding structure which concerns on the 6th Embodiment of this invention. The perspective view of the sliding structure which concerns on the modification of the 6th Embodiment of this invention. The perspective view of the sliding structure which concerns on the 7th Embodiment of this invention. The perspective view of the sliding structure which concerns on the modification of the 7th Embodiment of this invention. The perspective view of the aerial work vehicle which concerns on the 8th Embodiment of this invention. The perspective view of the fire-fighting ladder vehicle which concerns on the 9th Embodiment of this invention. The perspective view of the overlap part 18 of the 1st ladder part and the 2nd ladder part in FIG.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a perspective view of a crane truck according to an embodiment of the present invention, and FIG. 2 is an enlarged view of an overlapping portion 17 of two

work booms

7 and 8 in the crane truck of FIG.

A crane vehicle (work vehicle) shown in FIG. 1 includes a work device 40 composed of a plurality of long work booms (long structures) 7 and 8, and a crane 41 is provided at the tip of the work device 40. Is attached. The work boom (front-end work boom) 7 positioned on the front end side of the work device 40 can be housed inside the work boom (rear-end work boom) 8 positioned on the rear end side. It is formed to be slightly smaller and is combined with the rear end side work boom 8 in a nested manner. That is, the working device 40 includes a translational telescopic mechanism whose length can be expanded and contracted when the front end side working boom 7 and the rear end side working boom 8 are translated relative to each other, and the working radius can be adjusted by this mechanism. ing.

As shown in FIG. 2, the work boom 7 or work boom 8 positioned above each of the overlapping parts (overlapping part 17) of the front work boom 7 and the rear work boom 8 assembled in a nested manner The sliding structure 30 (30A, 30B) that slides is installed. In the present embodiment, in consideration of the load of the load suspended from the crane 41 and the weight of the

work booms

7 and 8 acting in the vertically downward direction, the front end side work boom 7 and the rear end side work boom 8 are

Sliding structures

30A and 30B are installed in portions that overlap in the vertical direction. Specifically, the sliding structure 30 A is installed below the lower surface of the outer side surface of the front end side work boom 7, and the rear end side is slidable with the outer side surface of the front end side work boom 7. It is fixed to the tip of the work boom 8. The sliding structure 30 B is installed below the upper surface of the inner side surface of the rear end side work boom 8, and the front end side work boom 7 is slidable with the inner side surface of the rear end side work boom 8. It is fixed at the rear end. From the viewpoint of improving the stability during sliding and the load resistance of the working device, it is preferable to install a plurality of sliding

structures

30A, 30B in the width direction of the working

booms

7, 8. In the embodiment, two

sliding structures

30A and 30B are respectively installed in the width direction of the work booms 7 and 8 (in FIG. 2, one

sliding structure

30A and 30B is provided for each

work boom

7 and 8. Only is shown).

3 is a perspective view of the sliding structure 30A according to the first embodiment of the present invention, and FIG. 4 is a cross-sectional view of the sliding structure 30A fixed to the tip of the work boom 8. As shown in FIG. In addition, the same code | symbol is attached | subjected to the same part as the previous figure, and description is abbreviate | omitted (the following figure is also the same).

The sliding structure 30 A shown in these drawings is formed between the two rollers 1 and the two rollers 1 disposed at intervals in the longitudinal direction of the rear end side work boom 8 (the expansion / contraction direction of the translational expansion / contraction mechanism). An installed pad 3, two rollers 1, and a support member 6 that supports the pad 3 are provided.

The support member 6 rotatably supports the two rollers 1 and the pad 3, and the rear end side work boom 8 is interposed via a pad base shaft (rotation shaft) 5 positioned between the two rollers 1. Is rotatably supported. As shown in FIG. 5 to be described later, the support member 6 is elastically deformed in a convex shape around the pad base shaft 5 in accordance with the magnitude of the load acting on the two rollers 1 via the distal end side work boom 7. It is made of a material (a material that bends in a convex shape). In addition, from the viewpoint of deforming the support member 6 in the same manner as the

work booms

7 and 8, it is preferable to form the same material (for example, carbon steel or stainless steel). The support member 6 in the present embodiment is a frame-like structure, and as shown in FIG. 2, the pad base shaft 5 is interposed in a hole provided by cutting out the lower surface on the front end side of the rear end side work boom 8. It is supported.

The roller 1 is a sliding member obtained by machining carbon steel, stainless steel, or aluminum alloy into a cylindrical shape by machining, and is fixed to the distal end side work boom 7 located above the sliding member so as to be always slidable. The roller 1 is supported by a roller shaft 2 via a sliding member (not shown) such as a bearing installed at its core portion, and is rotatable around the roller shaft 2.

The pad 3 is a sliding member that can come into contact with the work boom 7 on which the roller 1 slides, and is fixed to the upper part of the pad base 4. From the viewpoint of ensuring strength and slidability, the pad 3 is preferably formed of a fiber reinforced composite material. Further, as shown in FIG. 4, the pad 3 is formed so that the upper end surface thereof is positioned below the upper end surface of the roller 1 in a state where the load acting on the roller 1 is small and the support member 6 is not deformed. Has been. That is, in this state, the pad 3 is not in contact with the distal end side work boom 7. Further, pad base shafts 5 protrude from both side surfaces of the pad base 4, and the two pad base shafts 5 are supported by the rear end side work boom 8 through through holes provided in the support member 6. . In this embodiment, the rotation shafts of the support member 6 and the pad base 4 are combined with the pad base shaft 5 for simplification of the configuration. However, the rotation shafts of the support member 6 and the pad base 4 are individually provided. It may be provided.

On the other hand, as shown in FIG. 2, the sliding structure 30 B is rotatably supported via the pad base shaft 5 in a recess provided on the upper surface of the outer surface of the distal end side work boom 7. The roller 1 of the sliding structure 30B is supported by the support member 6 through the roller shaft 2 so as to be slidable at all times with the distal end side work boom 8 positioned above the roller 1. Further, the upper end surface of the pad 3 is formed to be positioned below the upper end surface of the roller 1 in a state where the support member 6 is not deformed. The other parts are the same as those of the sliding structure 30A, and the description thereof is omitted.

The operation of the sliding structure 30A configured as described above will be described with reference to FIGS. FIG. 5 is a cross-sectional view of the sliding structure 30 A when a load of a predetermined size or more is applied to the roller 1. Here, as shown in FIG. 5, the load having a predetermined magnitude means that when the pad 3 comes into contact with the lower surface of the work boom 7 for the first time as the support member 6 is elastically deformed in a convex shape upward, Indicates the applied load. In the following description, a load (set load) that acts on the roller 1 when a heavy object close to the design load of the work device 40 is suspended on the crane 41 as a load of a predetermined size that acts on the roller 1. It is assumed that it is set.

When the working device 40 is contracted or when the load acting on the crane 41 is small, the load acting on the roller 1 is smaller than the set load, so that the pad 3 does not come into contact with the distal work boom 7, and FIG. As shown, only the two rollers 1 are in contact with the lower surface of the work boom 7, and the telescopic operation of the work device 40 is performed. At this time, since the contact is caused by the cylindrical roller 1, the rotational motion is smoothly performed, and the expansion / contraction operation of the working device 40 is also smoothly performed. Further, since a sliding member such as a bearing is interposed between the roller 1 and the roller shaft 2, the deterioration of the roller 1 and the roller shaft 2 due to long-term use is small. In general work, there is little opportunity for heavy objects close to the design load to be suspended from the crane 41. Therefore, in most operating situations of the crane truck, only the roller 1 as shown in FIG. Telescopic operation is performed.

On the other hand, when a load exceeding the set load is applied to the roller 1 by hanging a heavy object very close to the design load of the work device 40 on the crane 41, the pad 3 contacts the work boom 7 as shown in FIG. Until then, the support member 6 is deformed, and the pad 3 is in contact with the lower surface of the work boom 7 in addition to the two rollers 1. When the pad 3 is in contact in this way, the contact stress between the roller 1 and the work boom 7 can be reduced compared to when only the roller 1 is in contact. By the way, even when a heavy object very close to the design load of the work device 40 is suspended from the crane 41, if the lower surface of the distal work boom 7 is supported by only two rollers 1 as shown in FIG. If the compressive stress of the contact portion exceeds the yield point of the member constituting the lower surface of the work boom 7, the lower surface of the work boom 7 may be plastically deformed. However, the crane truck according to the present embodiment is configured such that, in such a case, the pad 3 contacts the lower surface of the work boom 7 in addition to the two rollers 1 as described above. Thereby, even when a heavy load is applied to the work device 40, plastic deformation of the lower surface of the work boom 7 can be prevented without increasing the plate thickness of the lower surface of the work boom 7. That is, according to the present embodiment, it is possible to provide a work vehicle including a lightweight work device that does not deform even when a heavy load is applied. In general, since the situation in which the crane truck works with the maximum design load is limited, the time for the pad 3 to contact the lower surface of the work boom 7 is small. Therefore, even if it is used for a long time, the sliding property of the sliding structure 30 hardly changes, and the maintenance cycle of the pad 3 can be lengthened.

Further, in the present embodiment, from the viewpoint of suppressing contact stress generated between the roller 1 and the work boom 7 as much as possible, the contact with the work boom 7 is made only when a load of a predetermined magnitude or more is applied to the roller 1. As the sliding member, the pad 3 capable of being in surface contact with the work boom 7 was used. However, if the contact stress can be suppressed within a range in which plastic deformation of the work boom 7 can be prevented, a sliding member (for example, a roller or the like) that can be in line contact with the work boom 7 may be used instead of the pad 3. The pad 3 may be formed of metal or resin in addition to the fiber reinforced composite material described above. However, if the pad 3 is formed of a fiber reinforced composite material, scratches generated on the work boom 7 can be reduced as compared with the case of using a metal one, and moreover than the case of using a resin one. The wear amount of the pad 3 can be reduced.

Next, a second embodiment of the present invention will be described. This embodiment relates to a modification of the pad 3 in the first embodiment, FIG. 6 is a perspective view of the pad 3A according to the second embodiment of the present invention, and FIG. It is a perspective view of the pad 3B which concerns on the modification of the 2nd Embodiment of invention.

The pad 3A shown in FIG. 6 is formed by laminating a plurality of prepreg sheets 9 containing a semi-cured epoxy resin on a cloth woven with glass fibers orthogonal to each other and heating and pressing with a press plate. A cloth 10 woven with organic fibers orthogonal to each other is fixed on the surface in contact with the

booms

7 and 8. As a method of fixing the cloth 10 in this way, there are a method of integrally molding with the prepreg sheet 9 at the time of press molding of the pad 3A, and a method of adhering the cloth 10 to the upper surface of the pad 3A after molding. Examples of the organic fiber used for the fabric 10 include fibers made of polybenzimidazole, polyparaphenylenebenzobisoxazole, aromatic polyamide, polyarylate, and aromatic polyester.

The pad 3B shown in FIG. 7 is formed by laminating a plurality of prepreg sheets 9 in the same manner as the pad 3A, and the surface that comes into contact with the

work booms

7 and 8 is obtained by cutting organic fibers short (for example, from 1 mm A sheet 11 formed in a cloth shape is fixed. As a method for fixing the sheet 11, there are a method in which the sheet 11 is integrally formed with the prepreg sheet 9 at the time of press molding of the pad 3B, and a method in which the sheet 11 is adhered to the upper surface of the pad 3B after molding. What is necessary is just to use the thing similar to the fiber used for 10.

FIG. 8 is a diagram showing a change in friction coefficient between the fiber-reinforced composite material and the metal. As shown in this figure, the friction coefficient between the composite material formed only of the prepreg sheet 9 made of glass fiber and the metal increases as the number of friction repetitions increases. That is, if the pad 3 is made of a composite material made only of glass fibers, the coefficient of friction with the contact surface with the metal work boom 7 increases, and the expansion and contraction driving force of the

work booms

7 and 8 increases. There is a risk of causing an increase or an increase in the amount of wear on the pad 3 and the lower surface of the work boom 7.

On the other hand, when organic fibers are included in the surfaces in contact with the

work booms

7 and 8 such as the pads 3A and 3B according to the present embodiment, the friction coefficient increases as shown in FIG. Will not increase. That is, when the organic fiber is included on the side of the surface of the composite material using the glass fiber as the base material in contact with the

work booms

7 and 8 as in the present embodiment, the contact surface with the

metal work booms

7 and 8. An increase in the friction coefficient can be suppressed. Thereby, the expansion drive force of the

work booms

7 and 8 can be increased, and the wear amount of the pads 3A and 3B and the lower surface of the work boom 7 can be suppressed.

Next, a third embodiment of the present invention will be described. This embodiment relates to another modification of the pad 3 in the first embodiment, and FIG. 9 is a perspective view of a sliding structure including the pad 3C according to the third embodiment of the present invention. FIG.

In the sliding structure shown in this figure, the surface 15 where the pad 3C comes into contact with the

work booms

7 and 8 is formed as a curved surface having a constant curvature convex upward toward the

work booms

7 and 8. . When the surface where the pad 3 contacts the

work booms

7 and 8 is made flat as in the first embodiment, corners are formed at the ends of the flat surfaces, so that the pad 3 abruptly forms the

work booms

7 and 8. There is a possibility that the corners may be damaged when touching. On the other hand, when the surface 15 is provided in a curved shape as in the present embodiment, even if the working

booms

7 and 8 are suddenly contacted or contacted at various angles, the local compressive stress increases. Therefore, the reliability on the strength of the pad 3C can be improved.

Next, a fourth embodiment of the present invention will be described. This embodiment mainly differs from the first embodiment in the method of supporting the roller 1. FIG. 10 is a perspective view of a sliding structure 34 according to the fourth embodiment of the present invention.

The roller 1 shown in this figure is supported by a bearing 12 via a roller shaft 2. A leaf spring 13 that shrinks in the vertical direction according to the magnitude of the acting load is attached below the bearing 12, and the bearing 12 is fixed to the support member 6 via the leaf spring 13. In addition, as a method of coupling the bearing 12 and the leaf spring 13, and the leaf spring 13 and the support member 6, for example, there is bolt fastening. When the load acting on the roller 1 is small, the upper end surface of the pad 3 is positioned below the upper end surface of the roller 1, and when the load acting on the roller 1 reaches the set load, the upper end surface of the pad 3. The leaf spring 13 contracts before the contact with the work boom 7, and the pad 3 comes into contact with the work boom 7 for the first time. In the present embodiment, the pad 3 can be brought into contact with the work boom without using the elastic deformation of the support member 6 as in the first embodiment. You may fix to the front end of the boom 8 or the rear end of the front end side work boom 7 so that rotation is impossible.

In the present embodiment configured as described above, when a load is applied to the roller 1 and the leaf spring 13 contracts, the roller 1 sinks downward together with the bearing 12, and the pad 3 moves relative to the roller 1. Float upward. When the load acting on the roller 1 reaches the set load or more, the pad 3 comes into contact with the work boom 7 in addition to the roller 1. Thereby, since the compressive load which the roller 1 exerts on the work boom 7 reduces, the plastic deformation of the work boom 7 can be prevented.

If the leaf springs 13 are provided at both ends of the roller shaft 2 as in the present embodiment, even if there is a variation in the direction of the roller shaft 2 in the load acting on the roller 1 from the work boom, 2 according to the variation. Since the two leaf springs 13 are individually deformed, variations in the compressive load when the roller 1 contacts the lower surface of the work boom 7 can be reduced.

FIG. 11 is a perspective view of a sliding structure 34A according to a modification of the fourth embodiment of the present invention. The sliding structure 34A shown in this figure supports the bearing 12 via a coil spring 14 instead of the leaf spring 13 in FIG. Even if the bearing 12 is supported by the coil spring 14 in this way, the pad 3 can be brought into contact with the work boom 7 in addition to the roller 1 when the load acting on the roller 1 reaches a set load or more. As in the example of FIG. 10, the plastic deformation of the work boom 7 can be prevented. When the coil spring 14 is used as shown in FIG. 11, the load threshold value for sinking the roller 1 can be set finely by changing the number of turns of the coil spring 14. It will be an advantage over the case.

Next, a fifth embodiment of the present invention will be described. This embodiment is mainly different from the fourth embodiment in the number and arrangement of pads 3. FIG. 12 is a cross-sectional view of the sliding structure 35 according to the fifth embodiment of the present invention.

The sliding structure 35 shown in this figure is arranged so as to sandwich two rollers 1 arranged adjacently along the longitudinal direction of the work boom 8 and the two rollers 1 from the longitudinal direction of the work boom 8. And a support member 6 rotatably supported by the work boom 8 via a load transmission pin 16. The bearing 12 that supports the roller 1 is fixed on a shelf plate 25 attached to the side surface of the support member 6 via a leaf spring 13. Thereby, also in this embodiment, when the load acting on the roller 1 reaches the set load, the roller 1 moves downward and the two pads 3 in addition to the two rollers 1 come into contact with the lower surface of the work boom 7. To do. Thereby, also in this Embodiment, the plastic deformation of the work boom 7 can be prevented.

In particular, in the present embodiment, since two pads 3 are attached, the roller 1 and the pad 3 are compared with the case where there are two rollers 1 and one pad 3 as in the first embodiment. The load sharing can be further reduced. Further, in the present embodiment, the pad 3 is arranged so as to sandwich the roller 1 from the outside. Compared to the case of the first embodiment, the pad 3 is accessed when performing the pad replacement work. Since it is easy, replacement work can be performed speedily. In the present embodiment, the case where two rollers 1 and two pads 3 are attached has been described as an example. However, one or more rollers 1 may be provided, and one pad 3 may be provided. Three or more may be sufficient.

Next, a sixth embodiment of the present invention will be described. The present embodiment is mainly different from the first embodiment in the fixing method of the roller 1 and the pad 3. FIG. 13 is a perspective view of a sliding structure 36 according to the sixth embodiment of the present invention.

The sliding structure 36 shown in this figure includes a pad base 4 fixed to the lower surface of the inner surface of the rear end side work boom 8, a pad 3 fixed on the pad base 4, and a rear end side work boom 8. A bearing 12 fixed to a lower surface of the inner surface of the inner surface of the inner surface of the inner surface of the inner surface of the inner surface by a leaf spring 13 and a roller 1 supported by the bearing 12 through a roller shaft 2 are provided. Similarly to the fourth embodiment, the upper end of the pad 3 is positioned below the upper end of the roller 1 when the leaf spring 13 is extended as shown in FIG. 13, and the leaf spring 13 contracts. The height difference between the two is reduced.

Even when the sliding structure 36 configured in this way is used, when the load acting on the roller 1 becomes large, the pad 3 can be brought into contact with the lower surface of the distal working boom 7 in addition to the roller 1. Plastic deformation of the work boom 7 can be prevented. In particular, in the present embodiment, the support member 6 and the like as in the first embodiment are not necessary, so that the number of parts can be reduced and the manufacturing cost can be reduced.

FIG. 14 is a perspective view of a sliding structure 36A according to a modification of the sixth embodiment of the present invention. The sliding structure 36A shown in this figure includes a bearing 12 fixed to the lower surface of the inner surface of the rear end side working boom 8 via a leaf spring 13, and a roller 1 supported by the bearing 12 via a roller shaft 2. And two pad bases 4 fixed to the lower surface of the inner surface of the rear end side work boom 8 so as to sandwich the roller 1 from the direction of expansion and contraction of the work device 40, and fixed on the two pad bases 4 respectively. A pad 3D is provided. The pad 3D is formed so that its cross-sectional area increases as it approaches the work boom 7 from the viewpoint of securing a large contact area with the work boom 7 as much as possible. Similarly to the case of FIG. 13, when the leaf spring 13 is extended, the upper end portion of the pad 3D is positioned below the upper end portion of the roller 1, and when the leaf spring 13 contracts, the height difference between the two becomes smaller. It is like that.

Even when the sliding structure 36 A configured as described above is used, when the load acting on the roller 1 increases, the two pads 3 D in addition to the roller 1 can be brought into contact with the lower surface of the distal work boom 7. Therefore, plastic deformation of the work boom 7 can be prevented. In particular, in the present embodiment, as compared with the case of FIG. 13, the two pads 3 D having a large area are in contact with the work boom 7, so that the compressive load applied to the roller 1 can be further reduced.

Next, a seventh embodiment of the present invention will be described. The present embodiment is mainly different from the sixth embodiment in that the pad 3 is installed so as to be movable up and down. FIG. 15 is a perspective view of a sliding structure 37 according to the seventh embodiment of the present invention.

The sliding structure 37 shown in this figure includes a pad base 4 fixed to the lower surface of the inner surface of the rear end side work boom 8 via a leaf spring 13, a pad 3 fixed on the pad base 4, A bearing 12 fixed to the lower surface of the inner side surface of the rear end side working boom 8 and a roller 1 supported by the bearing 12 via a roller shaft 2 are provided. Unlike the sixth embodiment, in this embodiment, the upper end of the roller 1 is located below the upper end of the pad 3 when the leaf spring 13 is extended as shown in FIG. When 13 shrinks, the difference in height between the two becomes smaller. That is, in the present embodiment, the pad 3 can always slide on the lower surface of the work boom 7.

Even when the sliding structure 37 configured as described above is used, when the load acting on the pad 3 increases, the roller 1 can be brought into contact with the lower surface of the distal end side work boom 7 in addition to the pad 3. Plastic deformation of the work boom 7 can be prevented. In particular, in the present embodiment, since the roller 1 rotates, the work boom 7 can be smoothly expanded and contracted even when an excessive load is applied. When the pad 3 is made of metal (a metal softer than the work boom 7 is preferable), a lubricant such as grease is applied to the surface where the pad 3 comes into contact with the work boom 7 from the viewpoint of improving slidability. It is preferable to apply.

FIG. 16 is a perspective view of a sliding structure 37A according to a modification of the seventh embodiment of the present invention. The sliding structure 37 A shown in this figure includes a bearing 12 fixed to the lower surface of the inner surface of the rear end side working boom 8, a roller 1 supported on the bearing 12 via the roller shaft 2, and a working device 40. Two pad bases 4 fixed to the lower surface of the inner side surface of the rear end side work boom 8 via the leaf spring 13 so as to sandwich the roller 1 from the extending and contracting direction, and fixed on the two pad bases 4 respectively. A pad 3D is provided. As in the case of FIG. 15, when the leaf spring 13 is extended, the upper end of the roller 1 is located below the upper end of the pad 3D, and when the leaf spring 13 is contracted, the height difference between the two is reduced. It has become.

Even when the sliding structure 37A configured as described above is used, when the load acting on the two pads 3D increases, the roller 1 in addition to the two pads 3D is brought into contact with the lower surface of the distal working boom 7. Therefore, plastic deformation of the work boom 7 can be prevented. In particular, in the present embodiment, as compared with the case of FIG. 15, the two pads 3 D having a large area are in contact with the work boom 7, so that the compression load can be further reduced.

Next, an eighth embodiment of the present invention will be described. FIG. 17 is a perspective view of an aerial work vehicle according to an eighth embodiment of the present invention.

The aerial work vehicle shown in this figure includes a working device composed of three working booms combined in a nested manner, and has two working boom overlapping portions 17. Thus, even when there are a plurality of overlapping portions 17, if the sliding structure described in the previous embodiments is used for each overlapping portion 17, the same effects as in the previous embodiments are obtained. Obtainable.

Next, a ninth embodiment of the present invention will be described. This embodiment relates to a fire fighting ladder car. Generally, a ladder of a fire fighting ladder car is formed by a welded structure of a square steel pipe, and a thin plate having a thickness of about 2 to 5 mm is used. Therefore, when the maximum loading mass is mounted on the basket installed at the tip of the ladder and the ladder is fully extended, the sliding structure (roller lifting part) installed at the overlapping part of the ladder part High local stress was generated, which could cause plastic deformation or buckling deformation of the entire ladder. The present embodiment has been invented in view of this problem.

FIG. 18 is a perspective view of a fire ladder truck according to the ninth embodiment of the present invention. The fire fighting ladder car shown in this figure includes a four-stage ladder (working device) 50 composed of four ladder parts combined in a nested manner, and has three overlapping parts 18 of the ladder parts. A basket 55 is attached to the tip of the ladder 50. Here, the four ladder parts constituting the ladder 50 are arranged in order from the front end to the rear end of the ladder 50, the first ladder part 51, the second ladder part 52, the third ladder part 53, and the fourth ladder part 54. Called.

FIG. 19 is a perspective view of the sliding structure 39 in the overlapping portion 18 of the first ladder portion 51 and the second ladder portion 52. The sliding structure 39 shown in this figure is installed on the lower side of the lower bone 19 of the first ladder portion 51, and the lower bone 20 of the second ladder portion 52 is slidable with the lower bone 19. It is installed at the tip. As shown in FIG. 19, the lower bone 20 of the second ladder portion 52 has a gap extending in the expansion / contraction direction of the ladder 50, once split into two forks at the tip side, and then joined again. Yes. The support member 6 of the sliding structure 39 is accommodated in the space of the lower bone 20 and is supported by the lower bone 20 through the load transmission pin 16 so as to be rotatable. The support member 6 supports two rollers 1 that can always slide with the lower bone 19 and two pad bases 4 so as to be rotatable. The two pad bases 4 are arranged with the load transmission pin 16 in between, and the two rollers 1 are arranged with the two pad bases 4 in between. Pads 3 (not shown) are fixed on the two pad bases 4, and when the load acting on the roller 1 is small, the upper end of the pad 3 is located below the upper end of the roller 1.

In the fire fighting ladder car configured as described above, when the load at the tip of the ladder 50 increases and the load acting on the roller 1 via the lower bone 19 increases, the support member 6 is the same as in the case of the first embodiment. Is gradually elastically convex upward, so that when the load acting on the roller 1 reaches the set load, the two pads 3 come into contact with the lower bone 19 in addition to the two rollers 1. As a result, the maximum compressive stress on the lower surface of the lower bone 19 is reduced, so that the plastic deformation of the lower bone 19 is prevented. That is, according to the present embodiment, it is possible to provide a lightweight ladder that does not deform even when a heavy load is applied, so that the ladder can be expanded and contracted quickly, and the time required for rescue operations can be shortened. Can do.

In the above description, the configuration in which the lower bone 19 is supported by the two rollers 1 and the two pads 3 has been described as an example. However, the sliding structure in each embodiment described above using a crane vehicle as an example. It goes without saying that the body is applicable to ladder cars. In the above description, the sliding structure 39 installed between the lower bone 19 of the first ladder portion 51 and the lower bone 20 of the second ladder portion 52 has been described, but the upper bone 21 of the first ladder portion 51. If the same sliding structure 39 is installed at the rear end and the upper bone (not shown) of the second ladder portion 52 is supported via this, the same effect as described above can be obtained. Further, here, only the overlapping portion 18 of the first ladder portion 51 and the second ladder portion 52 has been described. However, if the sliding structure 39 is installed in the remaining two overlapping portions 18, the same effect as described above can be obtained. It goes without saying that it is obtained.

DESCRIPTION OF SYMBOLS 1 Roller 3 Pad 6 Support member 7 Front end side work boom 8 Rear end side work boom 9 Pre-preg sheet 10 Cloth 11 Sheet 12 Bearing 13 Leaf spring 14 Coil spring 15 Pad 16 having a certain curvature 16 Load transmission pin 17 Overlapping part of working boom 18 Overlapping part of ladder part 30, 34 to 37, 39 Sliding structure 40 Working device 50 Ladder

Claims

A work vehicle having a translational telescopic mechanism constituted by a plurality of long structures combined in a nested manner,
A first sliding member that is installed in a portion where two long structures that translate and expand and contract mutually overlap, and that slides with either of the two long structures;
For the first time, a long structure is installed in a portion where the two long structures overlap, and the first sliding member slides when a load of a predetermined size or more is applied to the first sliding member. A work vehicle comprising a second sliding member in contact with the work vehicle.
A work vehicle having a translational telescopic mechanism constituted by a plurality of long structures combined in a nested manner,
Two long structures that translate and expand and contract with each other are fixed to one long structure so that they are positioned in the overlapping portion in the vertical direction, and the other long structure positioned above the one long structure, A first sliding member that slides;
When the two long structures are fixed to the one long structure so as to be located in a portion where the two long structures overlap in the vertical direction, and when a load of a predetermined magnitude or more is applied to the first sliding member, A work vehicle comprising: a second sliding member that makes contact with the other long structure for the first time.
The work vehicle according to claim 1,
Two of the first sliding members are installed with a gap in the longitudinal direction of the long structure,
The second sliding member is installed so as to be positioned between the two first sliding members,
The two first sliding members are rotatably fixed to one of the two long structures via a rotation shaft positioned between the two first sliding members. And a support member that rotatably supports each of the second sliding members,
The work vehicle, wherein the support member is formed of a material that is elastically deformed in a convex shape in accordance with the magnitude of a load acting on the two first sliding members.
The work vehicle according to claim 1,
The first sliding member is fixed to one of the two long structures through an elastic body that contracts in the vertical direction according to the magnitude of the acting load. Working vehicle.
The work vehicle according to claim 1,
One of the first sliding member and the second sliding member is a roller,
2. The work vehicle according to claim 1, wherein the other of the first sliding member and the second sliding member is a pad that can come into surface contact with an elongated structure that slides on the roller.
The work vehicle according to claim 5,
The pad is formed of a fiber reinforced composite material, and an organic fiber is included on a surface that contacts the long structure.
The work vehicle according to claim 5,
The work vehicle is characterized in that a surface of the pad that comes into contact with the long structure is formed with a curved surface that is convex toward the long structure.
The work vehicle according to claim 4,
The working vehicle, wherein the elastic body is a leaf spring or a coil spring.
The work vehicle according to claim 4,
One of the first sliding member and the second sliding member is two or more rollers,
The working vehicle, wherein the other of the first sliding member and the second sliding member is two or more pads that can come into surface contact with an elongated structure that slides with the roller.