JP3134434U - Mast support structure - Google Patents

Abstract

A mast support structure capable of suppressing the occurrence of cracks and breakage is provided.
A mast support structure 1 constitutes a part of a forklift cargo handling device and includes a pair of mast portions 2 and 2 and a lower beam (beam portion 3). The pair of mast portions 2 and 2 are arranged in parallel to each other. The lower beam 3 includes a main body portion 4 and a pair of reinforcing portions 5 and 5 provided at both ends of the main body portion 4, and a pair of mast portions 2 and 2 for supporting the pair of mast portions 2 and 2. And orthogonally arranged. The main body 4 is used as a support for a lift cylinder for lifting operation in the cargo handling device. Each of the pair of reinforcing portions 5, 5 is coupled to each of the pair of mast portions 2, 2 by welding so as to follow the pair of mast portions 2, 2. Further, both end portions of the main body portion 4 and the pair of reinforcing portions 5 and 5 are integrally formed.
[Selection] Figure 3

Description

  The present invention relates to a mast support structure constituting a part of a cargo handling device of a forklift.

  Examples of conventional mast support devices are disclosed in Patent Document 1 and Patent Document 2. In the technique of Patent Document 1, the lower ends of the left and right outer masts are connected to each other by a lower beam. A lift cylinder is disposed behind the mast, and the lift cylinder is supported by the lower beam. Reinforcing members are respectively disposed on the rear surfaces of the lower end portions of the left and right outer masts and on the outer side of the lift cylinder, and these reinforcing members are vertically long plate members having a substantially rectangular cross section in the front and rear direction. The front end edge is fixed to the rear surface of the outer mast by welding. The left and right edges of the lower beam are fixed to the lower ends of the inner side surfaces of the left and right reinforcing members by welding, and face the rear surface of the outer mast with a slight gap. As described above, when the configuration in which the lower beam is fixed to the outer mast through the reinforcing member is adopted, the height of the reinforcing member can be set large. Therefore, the section modulus can be increased (compared to a configuration in which the lower beam is fixed to the outer mast without using a reinforcing member), and the stress in the vicinity of the welded portion A can be greatly reduced.

  Further, in the technique of Patent Document 2, a structure is proposed in which ribs (reinforcing plates) that are joined to the mast rail are added in the plane where the cross member and the mast rail are orthogonal to each other and on the side of the lift cylinder. By increasing, the welding strength is secured.

Japanese Patent Laid-Open No. 6-1594 (FIG. 3) JP 2006-306604 A (FIG. 9)

  In the above-described prior art, the reinforcing member and the lower beam (Patent Document 1), or the rib (reinforcing plate) and the cross member (Patent Document 2) are joined by welding. Therefore, depending on the working conditions, local high stress may be generated in the welded joint, which may cause cracks or breakage.

  Therefore, an object of the present invention is to provide a mast support structure that can suppress the occurrence of cracks and breakage.

Means and effects for solving the problems

  In order to achieve the above object, a mast support structure according to the present invention is a mast support structure that constitutes a part of a cargo handling device of a forklift, and is a pair of masts that are formed in a rail shape and arranged in parallel to each other. And a beam portion disposed so as to be orthogonal to the pair of mast portions in order to support the pair of mast portions. The beam portion includes a main body portion extending perpendicular to the pair of mast portions, and a pair of reinforcing portions provided at both ends of the main body portion, and the main body portion is moved up and down in the cargo handling device. Each of the pair of reinforcing portions is coupled to each of the pair of mast portions by welding so as to follow the pair of mast portions, and both ends of the body portion The part and the pair of reinforcing parts are integrally formed.

  Since a lift cylinder is installed in the beam portion, a load is applied to the base portion of the lift cylinder during a cargo handling operation of the forklift, resulting in stress concentration in the vicinity of the connection portion between the beam portion and the mast portion. Here, if the main body part and the reinforcing part are joined by welding in the beam part, high stress may be generated in the joining part by this welding depending on the working conditions, which may cause cracks or breakage. obtain. On the other hand, according to the above-described configuration of the present invention, the both end portions of the main body portion and the reinforcing portion are integrally formed, so that compared with the case where they are joined by welding, the local height in this portion is increased. Generation of stress can be suppressed. Moreover, since the reinforcement part is provided, the contact area of a reinforcement part and a mast part can be set large, the full length of a welding line can be lengthened, and the intensity | strength of the connection part of a beam part and a mast part can be increased. As described above, a mast support structure capable of suppressing the occurrence of cracks and breakage is obtained.

  The main body portion may be coupled to the pair of mast portions by welding. According to this, not only the reinforcing part but also the main body part is coupled to the mast part, and the total length of the weld line at the joint part of the beam part and the mast part is further increased, so that the occurrence of cracks and breakage are prevented. It can be deterred more reliably.

  The main body portion includes a center support portion and a pair of end support portions provided at both ends of the center support portion, and each of the pair of end support portions includes a pair of the above-described end support portions. It may be used as a support for each lift cylinder, and the center support portion and the pair of end support portions may be joined by welding. According to this, the flexibility of the design of the mast support structure is improved, for example, the strength of the end support portion is increased as the support base of the lift cylinder, and the strength of the central support portion is lower than that of the end support portion. It becomes possible.

  In the main body, the thickness of the central support portion may be smaller than the thickness of the pair of end support portions. A high strength is required for the end support as a support for the lift cylinder. Therefore, in this way, by thickening only the end support part and making the central support part thinner than the end support part, it is possible to minimize the weight and material cost while ensuring the strength as a support base. It becomes possible.

  The reinforcing part may be formed to have a plate-like part, and each of the pair of mast parts may be in contact with at least a part of one surface part of the plate-like part. According to this, since the reinforcing part has a plate-like part and contacts the mast part at the surface part instead of the side part, the contact area between the mast part and the reinforcing part can be set large, and the overall length of the weld line is lengthened. Thus, the strength of the connecting portion can be reliably increased.

  Hereinafter, an embodiment of the present invention will be described. FIG. 1 is a schematic side view of a cargo handling apparatus including a mast support structure according to an embodiment of the present invention. FIG. 2 is a schematic perspective view of the mast support structure of FIG. FIG. 3 is an enlarged perspective view showing the lower beam (beam portion) periphery of the mast support structure of FIG. 2 in an enlarged manner.

(overall structure)
First, a cargo handling apparatus including a mast support structure 1 according to this embodiment will be described with reference to FIG. The cargo handling apparatus shown in FIG. 1 is provided at the front of a forklift main body (not shown), and includes a lift chain 17, a fork 10, a lift bracket 13, a chain wheel 11, an inner mast 12, a mast support structure 1, a lift. A cylinder 14 is provided. The mast support structure 1 includes a mast portion (outer mast) 2, a lower beam (beam portion) 3, and beams 15 and 16. FIG. 1 shows a state where the fork 10 is raised to the highest position. Further, in reality, the cargo handling section of the forklift includes a configuration in which the two cargo handling devices shown in FIG. 1 are arranged symmetrically, and these two cargo handling devices are similarly configured.

  The inner mast 12 moves up and down with respect to the mast support structure 1 having the mast portion (outer mast) 2, and the mast portion 2 functions as a rail in the lifting operation of the inner mast 12. The fork 10 is fixed to a lift bracket 13. The lift bracket 13 and the fork 10 are moved up and down with respect to the inner mast 12, and the inner mast 12 functions as a rail in the lifting operation of the lift bracket 13. The lift cylinder 14 includes a cylinder tube 14t and a piston rod 14r. The cylinder tube 14t is fixed to the lower beam 3 at the bottom of the mast support structure 1, and the tip of the piston rod 14r is fixed to the inner mast 12.

  A chain wheel 11 is attached to the inner mast 12. The lift chain 17 is supported by the chain wheel 11, and one end thereof is attached to the lift bracket 13 and the other end is attached to the mast support structure 1. With the above configuration, in the forklift cargo handling device, the inner mast 12 moves up and down as the lift cylinder 14 extends and retracts, and the lift bracket 13 and the fork 10 move up and down as the inner mast 12 moves up and down. In FIG. 1, the other end of the lift chain 17 is mounted in the vicinity of the beam 15. However, the configuration is not limited to such a configuration. For example, the lift chain 17 may be mounted on the mast portion 2.

(Mast support structure)
Next, the mast support structure 1 according to the present embodiment will be described. The mast support structure 1 constitutes a part of a forklift cargo handling device, and includes a pair of mast parts (outer masts) 2 and 2, a lower beam (beam part) 3, a middle beam 15, and an upper beam 16. It is configured. Details of each part will be described below.

(Mast part)
The mast portions 2 and 2 function as rails in the raising and lowering operation of the inner mast 12, and each of the pair of mast portions 2 and 2 is formed in a rail shape and is arranged in parallel to each other. And if a pair of mast parts 2 and 2 are attached to a forklift, it will be in the state arranged so that the longitudinal direction may follow a perpendicular line direction. In the present embodiment, the mast portion is formed so as to have a U-shaped cross section. However, the mast portion may be formed in a rail shape, and the cross section may be H-shaped. Even if it is other shapes, it may be formed in a rail shape according to the shape of the inner mast. A rail surface 2 r is formed on the inner surface of the mast portion 2.

(Lower beam)
The lower beam (beam part) 3 is disposed so as to be orthogonal to the pair of mast parts 2 and 2 in order to support the pair of mast parts 2 and 2 (see FIGS. 2 and 3). Further, the lower beam 3 includes a main body portion 4 extending so as to be orthogonal to the pair of mast portions 2, 2, and a pair of reinforcing portions 5, 5 provided at both ends of the main body portion 4. (See FIG. 3). Further, when described in the front-rear direction in a state where the mast support structure 1 is attached to the forklift (see the arrow direction in FIGS. 2 and 3), the lower beam 3 is disposed on the rear side with respect to the pair of mast portions 2 and 2. (See FIGS. 2 and 3).

  The main body 4 is used as a support for the lift cylinder 14 for lifting operation in the cargo handling device. More specifically, the main body portion 4 includes a central support portion 4m and a pair of end portion support portions 4t and 4t provided at both ends of the central support portion 4m (see FIG. 3). And each of a pair of edge part support parts 4t and 4t is used as each support stand of a pair of lift cylinder. Further, the center support portion 4m and the pair of end support portions 4t, 4t are coupled by welding (details will be described later). Further, installation holes 4h, 4h are formed along the longitudinal direction of the mast portion 2 on the upper surfaces of the pair of end support portions 4t, 4t in the drawing. And the protrusion part is formed in the bottom part of a pair of lift cylinder, The state where a pair of lift cylinder was attached to the main-body part 4 by inserting this protrusion part in the hole 4h, 4h for installation, Become. As described above, the lift cylinder 14 is supported by the main body 4.

  Moreover, the main-body part 4 is couple | bonded with a pair of mast parts 2 and 2 by welding. More specifically, the pair of end support portions 4t, 4t of the main body portion 4 and the pair of mast portions 2, 2 are joined by welding (see FIG. 3). Details of the welded portion will be described later.

  Further, in the main body 4, the thickness Tm of the central support 4m is thinner than the thickness Tt of the pair of end supports 4t, 4t (see FIG. 5 which is a front view taken along the line BB ′ in FIG. 3). ).

  The pair of reinforcing portions 5, 5 are formed so as to protrude from the pair of end support portions 4 t, 4 t along the longitudinal direction of the pair of mast portions 2, 2 at both ends of the main body portion 4. In order to avoid contact with the lift cylinder 14, the reinforcing portion 5 is thinner than the main body portion 4. In the present embodiment, the reinforcing portions 5 and 5 are formed so as to protrude upward from the main body portion 4 when described in the vertical direction in a state where the mast support structure 1 is attached to the forklift. And each of a pair of reinforcement parts 5 and 5 is couple | bonded with each of a pair of mast parts 2 and 2 by welding so that a pair of mast parts 2 and 2 may be met (refer FIG. 3). Further, both end portions of the main body portion 4 and the pair of reinforcing portions 5 and 5 are integrally formed. That is, the pair of end support portions 4t and 4t and the pair of reinforcement portions 5 and 5 in the main body portion 4 are integrally formed.

  Each of the reinforcing portions 5 of the pair of reinforcing portions 5 and 5 includes a plate-like portion 5p and an inclined portion 5b inclined with respect to the plate-like portion 5p (see FIG. 3). And each of a pair of mast parts 2 and 2 is in the state which contacted the whole one surface part (any one of a surface part and a back surface part) in plate-like part 5p. Further, the mast portion 2 is formed with a side surface 2v facing the rear side and an end surface 2s facing the other mast portion 2, and the plate-like portion 5p is in contact with the side surface 2v and is inclined. The part 5b is inclined with respect to the plate-like part 5p so as to approach the end surface 2s (see FIG. 4 which is a cross-sectional view taken along the line AA ′ in FIG. 3). Thus, the reinforcement part 5 is formed so that the surface area of the reinforcement part 5 may become large, and the plate-shaped part 5p and the inclination part 5b are the shapes which cover the corner | angular part of the mast part 2. Thus, since the lower beam 3 can stably support the pair of mast portions 2 and 2 and stress is dispersed in the reinforcing portion 5 when stress is generated, local stress concentration can be suppressed.

(About the middle and upper beams)
The beam 15 and the beam 16 are also arranged so as to be orthogonal to the pair of mast portions 2 and 2 so as to support the pair of mast portions 2 and 2 (see FIG. 2). Further, the beams 15 and 16 and the pair of mast portions 2 and 2 are coupled by welding.

(About welded joints)
Next, the joint part by welding in the mast support structure 1 will be described with reference to FIGS. 4 is a cross-sectional view taken along line AA ′ of FIG. FIG. 5 is a front view taken along the line BB ′ of FIG. FIG. 6 is a side view taken along the line CC ′ of FIG. 5 corresponds to the BB ′ arrow view of FIG. 3, and FIG. 6 corresponds to the CC ′ arrow view of FIG. In addition, since the periphery of the pair of mast portions 2 and 2 is configured symmetrically, FIGS. 4 to 6 show only the periphery of one mast portion 2 of the pair of mast portions 2 and 2. The other is not shown.

  First, the connection between the main body portion 4 and the mast portion 2 will be described. As described above, the main body portion 4 is joined to the pair of mast portions 2 and 2 by welding, and more specifically, the pair of end support portions 4t and 4t and the pair of mast portions 2 and 2. 2 are connected by welding. Referring to FIGS. 4 to 6, the weld lines of the joint portions are weld lines 10A, 10B, 10C, and 10D. 5C is a hidden portion that does not originally appear in the front view (FIG. 5) (see FIG. 4). The weld line 10C is formed by welding so as to couple the inclined portion 5b of the reinforcing portion 5 and the end surface 2s of the mast portion 2 (see FIG. 4).

  Further, as described above, the center support portion 4m and the pair of end support portions 4t and 4t are joined by welding. If it demonstrates with FIG. 4, 5, the weld line of this part will be the weld lines 10E, 10F, 10G, and 10H.

  As described above, the mast support structure 1 is configured by welding and joining the respective parts.

  Next, the effect of this embodiment will be described. The mast support structure 1 according to the present embodiment is a mast support structure 1 that constitutes a part of a forklift cargo handling device, and is formed in a rail shape and arranged in parallel to each other, In order to support the pair of mast portions 2, 2, a lower beam (beam portion) 3 disposed so as to be orthogonal to the pair of mast portions 2, 2 is provided. The lower beam 3 includes a body part 4 extending so as to be orthogonal to the pair of mast parts 2, 2, and a pair of reinforcing parts 5, 5 provided at both ends of the body part 4. It is used as a support for a lift cylinder 14 for lifting operation in a cargo handling device, and each of the pair of reinforcing portions 5 and 5 is along the pair of mast portions 2 and 2 with respect to each of the pair of mast portions 2 and 2. Thus, both ends of the main body portion 4 and the pair of reinforcing portions 5 and 5 are integrally formed.

  Since a lift cylinder is installed in the lower beam (beam part) 3, during the loading operation of the forklift, a load is applied to the base part of the lift cylinder, resulting in the lower beam (beam part) 3 and the mast parts 2, 2 Stress concentrates near the connection area. Here, if the main body 4 and the reinforcing portion 5 are coupled by welding in the lower beam 3, depending on the working conditions, the welding portion (corresponding to the portion 5c in FIGS. 3, 5 and 6) is high. Stress may occur, which may cause cracks or breakage. On the other hand, according to the configuration of the present embodiment described above, both end portions of the main body portion 4 and the reinforcing portions 5 and 5 are integrally formed, so this portion is compared with the case where they are joined by welding. Generation of local high stress in (5c portion) can be suppressed. Further, since the reinforcing portion 5 is provided, the contact area between the reinforcing portion 5 and the mast portion 2 is set to be large so that the entire length of the weld line is increased, and the strength of the connecting portion between the lower beam 3 and the mast portions 2 and 2 is increased. Can be increased. As described above, a mast support structure capable of suppressing the occurrence of cracks and breakage is obtained.

  The main body 4 is coupled to the pair of masts 2 and 2 by welding. Therefore, not only the reinforcing portion 5 but also the main body portion 4 is coupled to the mast portions 2 and 2, and the total length of the weld line at the joint portion between the lower beam 3 and the mast portions 2 and 2 is further increased. Cracks and breakage can be more reliably prevented.

  The main body part 4 includes a center support part 4m and a pair of end support parts 4t and 4t provided at both ends of the center support part 4m, and the pair of end support parts 4t and 4t. These are used as support bases for the pair of lift cylinders, and the center support portion 4m and the pair of end support portions 4t, 4t are coupled by welding. Therefore, the design flexibility of the mast support structure is improved, for example, the strength of the end support portion is increased as a support for the lift cylinder, and the strength of the center support portion is made lower than that of the end support portion. Is possible.

  In the main body part 4, the thickness Tm of the center support part 4m is thinner than the thickness Tt of the pair of end part support parts 4t, 4t. The end support 4t is required to have high strength as a lift cylinder support. Therefore, in this way, only the end support portion 4t is thickened, and the central support portion 4m is made thinner than the end support portions 4t and 4t, thereby ensuring the strength as a support base and minimizing the weight and material cost. It becomes possible to limit to the limit.

  The reinforcing portion 5 is formed to have a plate-like portion 5p, and each of the pair of mast portions 2 and 2 is in contact with at least a part of one surface portion of the plate-like portion 5p. According to this configuration, the reinforcing portion 5 has the plate-like portion 5p and contacts the mast portion 2 at the surface portion instead of the side portion thereof, so that the contact area between the mast portion 2 and the reinforcing portion 5 can be set large, welding By increasing the total length of the wire, the strength of the connecting portion can be reliably increased.

  As mentioned above, although embodiment of this invention was described, this invention is not restricted to the above-mentioned embodiment, It can implement in various changes.

  In the above embodiment, the mast support structure is applied as a support structure having an outer mast. However, the mast support structure according to the present invention may be applied as a support structure having an inner mast. In the case of the full free type, since the cylinder is supported by the inner mast, the same structure as that of the above embodiment can be adopted as the support structure having the inner mast.

  Further, in the above embodiment, the main body portion is coupled to the pair of mast portions by welding, but is not limited to such a configuration, only the reinforcing portion is coupled to the pair of mast portions, The main body portion and the mast portion may not be coupled.

  Further, in the above embodiment, the main body portion is configured by welding the separately formed central support portion and the pair of end support portions by welding. Is not limited, and the entire main body may be integrally formed. In other words, the entire main body portion and the pair of reinforcing portions (the entire lower beam (beam portion)) may be integrally formed.

  In the above embodiment, two lift cylinders are attached to the mast support structure. However, the present invention is not limited to this. For example, only one lift cylinder may be attached. Three or more may be attached. Further, in the above-described embodiment, the end support portions at both ends of the beam portion are the lift cylinder support bases. However, the present invention is not limited to this, and the central support portion is the lift cylinder support base. It may be.

  Further, in the above embodiment, the thickness of the central support portion is thinner than the thickness of the pair of end support portions, but such a configuration is not necessary, for example, the thickness of the central support portion. May be equal to or greater than the thickness of the pair of end support portions.

  In the above embodiment, the reinforcing portion is formed to have a plate-like portion, and one surface portion thereof is in contact with the mast portion. However, the configuration is not limited to this, and the plate-like portion The side surface portion and the mast portion may be in contact with each other (however, the contact area becomes smaller and the length of the weld line becomes shorter).

  Moreover, in said embodiment, each of a pair of mast part is the state which contacted the whole one surface part in a plate-shaped part. However, each of the pair of mast portions only needs to be in contact with at least part of one surface portion of the plate-like portion, and each of the pair of mast portions is in contact with part of one surface portion. May be.

1 is a schematic side view of a cargo handling apparatus including a mast support structure according to an embodiment of the present invention. FIG. 2 is a schematic perspective view of the mast support structure of FIG. 1. It is the expansion perspective view which expanded and showed the lower beam (beam part) periphery of the mast support structure of FIG. FIG. 4 is a cross-sectional view taken along arrow A-A ′ in FIG. 3. FIG. 4 is a front view taken along arrow B-B ′ in FIG. 3. FIG. 4 is a side view taken along the line C-C ′ of FIG. 3.

Explanation of symbols

1 Mast support structure 2 Mast part 3 Lower beam (beam part)
4 Main body portion 4m Center support portion 4t End support portion 5 Reinforcement portion 5p Plate-like portion

Claims (5)

A mast support structure that constitutes a part of a cargo handling device of a forklift,
A pair of mast portions formed in a rail shape and arranged parallel to each other;
A beam portion disposed to be orthogonal to the pair of mast portions in order to support the pair of mast portions;
The beam portion includes a main body portion extending so as to be orthogonal to the pair of mast portions, and a pair of reinforcing portions provided at both ends of the main body portion,
The main body is used as a support for a lift cylinder for lifting operation in the cargo handling device,
Each of the pair of reinforcing portions is coupled to each of the pair of mast portions by welding so as to follow the pair of mast portions,
The mast support structure, wherein both end portions of the main body portion and the pair of reinforcing portions are integrally formed.   The mast support structure according to claim 1, wherein the main body portion is coupled to the pair of mast portions by welding. The main body portion includes a central support portion and a pair of end support portions provided at both ends of the central support portion.
Each of the pair of end support portions is used as a support for each of the pair of lift cylinders,
The mast support structure according to claim 1 or 2, wherein the central support portion and the pair of end support portions are coupled by welding.   4. The mast support structure according to claim 3, wherein in the main body portion, the thickness of the central support portion is thinner than the thickness of the pair of end support portions. The reinforcing part is formed to have a plate-like part,
5. The mast support structure according to claim 1, wherein each of the pair of mast portions is in contact with at least a part of one surface portion of the plate-like portion. .

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