Boom telescopic driving unit and boom unit

Abstract

To provide a boom telescopic driving unit capable of achieving weight reduction and of suppressing an increase in dimension along the telescopic direction, while ensuring a large stroke of a boom telescopic cylinder.SOLUTION: In a boom telescopic driving unit, a cylinder rod of a boom telescopic cylinder is connected to a base boom member and a trunnion block can be moved together with a cylinder tube. A grip member can be changed to a storage state to be stored in the trunnion block and to a protruding state protruding from the trunnion block, and enables the trunnion block to be connected to any one of one or more moving boom members in the protruding state. A grip driving cylinder is connected to the grip member in a state where it is located outside the trunnion block, and changes the grip member to the storage state against an energizing force from an energizing member by being driven.SELECTED DRAWING: Figure 5

Description

[Technical field]

[0001] The present invention relates to a boom telescopic drive unit for a construction machine, and a boom unit equipped with the boom telescopic drive unit. [Background technology]

[0002] Patent Document 1 discloses a boom unit equipped with a multi-stage boom. The multi-stage boom includes a base boom member that is the first stage (first stage), and a movable boom member that is movable in the longitudinal direction relative to the base boom member. In the boom unit, a boom telescopic drive unit that telescopically operates the multi-stage boom is provided inside the multi-stage boom. The boom telescopic drive unit includes a boom telescopic cylinder, which can be telescopically extended by movement of a cylinder tube relative to a cylinder rod. The boom telescopic cylinder extends or retracts with the telescopic direction aligned with the longitudinal direction of the multi-stage boom. In addition, the cylinder rod of the boom telescopic cylinder is connected to the base boom member.

[0003] In the above-mentioned Patent Document 1, a trunnion block is provided in the boom telescopic drive unit, and the trunnion block is movable together with the cylinder tube in the telescopic direction of the boom telescopic cylinder (longitudinal direction of the multi-stage boom). In the boom telescopic drive unit, a grip member is attached to the trunnion block, and the grip member can be changed between a stored state in which it is stored in the trunnion block and a protruding state in which it protrudes from the trunnion block. In the boom telescopic drive unit, when the grip member is in the protruding state, the trunnion block can be connected to any one of one or more movable boom members via the grip member. In addition, when the trunnion block is connected to any one of the movable boom members, the movable boom member connected to the trunnion block moves along the longitudinal direction of the multi-stage boom in response to the telescopic drive of the boom telescopic cylinder, and the multi-stage boom performs telescopic operation.

[0004] In addition, in the above-mentioned Patent Document 1, a biasing member and a grip drive cylinder are built into the trunnion block. The biasing member, such as a coil spring, biases the grip member to a protruding state. In the boom telescopic drive unit, the grip drive cylinder is driven by hydraulic pressure or the like, so that the grip member changes to a stored state against the biasing force from the biasing member. When the grip member is in the stored state, the trunnion block is not connected to any of the movable boom members. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent No. 5586573 Summary of the Invention [Problem to be solved by the invention]

[0006] In a boom telescopic drive unit like that in Patent Document 1, there is a demand for reducing the weight of the entire boom telescopic drive unit by reducing the weight of the trunnion block, etc. There is also a demand for suppressing an increase in the dimension (total length) of the boom telescopic drive unit in the telescopic direction of the boom telescopic cylinder while ensuring a large stroke of the boom telescopic cylinder, by reducing the dimension of the trunnion block in the telescopic direction of the boom telescopic cylinder (longitudinal direction of the multi-stage boom), etc.

[0007] The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide a boom telescopic drive unit that ensures a large stroke of the boom telescopic cylinder while being lightweight and minimizing increases in the dimension along the telescopic direction, and a boom unit equipped with such a boom telescopic drive unit. [Means for solving the problem]

[0008] In order to achieve the above-mentioned object, one embodiment of the present invention provides a multi-stage boom having a base boom member and one or more movable boom members movable relative to the base boom member, the multi-stage boom having a boom telescopic drive unit which telescopically operates the multi-stage boom, the boom telescopic drive unit comprising: a boom telescopic cylinder having a cylinder rod connected to the base boom member and a cylinder tube movable relative to the cylinder rod, the boom telescopic cylinder being extendable and retractable by movement of the cylinder tube; a trunnion block movable together with the cylinder tube; a grip member attached to the trunnion block so as to be changeable between a stored state in which the trunnion block is stored and a protruding state in which the trunnion block protrudes, the grip member enabling connection of the trunnion block to any one of the one or more movable boom members in the protruding state; a biasing member which biases the grip member to the protruding state; and a grip drive cylinder which is connected to the grip member while positioned outside the trunnion block, and which, when driven, changes the grip member to the stored state against the biasing force of the biasing member. Effect of the Invention

[0009] The present invention makes it possible to provide a boom telescopic drive unit that ensures a large stroke of the boom telescopic cylinder while being lightweight and that limits any increase in dimension in the telescopic direction, and a boom unit that is equipped with this boom telescopic drive unit. [Brief description of the drawings]

[0010] [Figure 1] FIG. 1 is a side view showing a crane according to a first embodiment. [Diagram 2] FIG. 2 is a schematic diagram showing the configuration of the boom unit according to the first embodiment. [Diagram 3] FIG. 3 is a perspective view showing a boom telescopic drive unit according to the first embodiment. FIG. [Figure 4]FIG. 4 is a cross-sectional view showing the internal configuration of the multi-stage boom in a cross section perpendicular or substantially perpendicular to the width direction in the boom unit according to the first embodiment. [Diagram 5] FIG. 5 is a perspective view showing the trunnion block and its vicinity in a protruding state of the grip member in the boom telescopic drive unit according to the first embodiment. [Figure 6] FIG. 6 is a perspective view showing the trunnion block and its vicinity in the boom telescopic drive unit according to the first embodiment in a state in which the grip member is in a protruding state and viewed from a different direction than that in FIG. 5. [Figure 7] FIG. 7 is a perspective view showing the trunnion block and its vicinity in a stored state of the grip member in the boom telescopic drive unit according to the first embodiment. [Figure 8] FIG. 8 is a plan view showing the trunnion block and its vicinity in the boom telescopic drive unit according to the first embodiment, as viewed from above in the height direction of the boom unit. [Figure 9] FIG. 9 is a side view showing the trunnion block and its vicinity in the boom telescopic drive unit according to the first embodiment, as viewed from one side in the width direction of the boom unit. [Figure 10] FIG. 10 is a cross-sectional view taken along line F1-F1 in FIG. [Figure 11] FIG. 11 is a cross-sectional view taken along line F2-F2 of FIG. 10, showing the grip member in a protruding state. [Figure 12] FIG. 12 is a cross-sectional view taken along line F2-F2 of FIG. 10, showing the grip member in a stored state. [Figure 13] FIG. 13 is a cross-sectional view illustrating a mechanism for operating the grip members by driving the grip drive cylinder in the boom extension and contraction drive unit according to the first embodiment, in a protruding state of the grip members. [Figure 14] FIG. 14 is a cross-sectional view illustrating a mechanism for operating the grip members by driving the grip drive cylinder in the boom extension and contraction drive unit according to the first embodiment, in a stored state of the grip members. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] Hereinafter, an embodiment will be described with reference to the drawings.

[0012] (First embodiment) First, a first embodiment will be described as an example of an embodiment. In the first embodiment, a crane 1 is provided as a construction machine. FIG. 1 shows the crane 1 according to the first embodiment. As shown in FIG. 1, the crane 1 includes a traveling body 2 and a rotating body 3. The rotating body 3 is connected to the traveling body 2 from the vertically upper side (the side indicated by the arrow Z1). The rotating body 3 is capable of rotating with respect to the traveling body 2, centering on a rotation axis P along the vertical direction (the direction indicated by the arrows Z1 and Z2).

[0013] In the rotating body 3, a front-rear direction (direction indicated by arrows X1 and X2) that intersects (perpendicular or approximately perpendicular) with the vertical direction, and a width direction (direction perpendicular or approximately perpendicular to the paper surface in FIG. 1) that intersects (perpendicular or approximately perpendicular) with both the vertical direction and the front-rear direction are defined. In addition, in the traveling body 2, a front-rear direction that intersects (perpendicular or approximately perpendicular) with the vertical direction, and a width direction that intersects (perpendicular or approximately perpendicular) with both the vertical direction and the front-rear direction are defined. FIG. 1 shows a state in which the front-rear direction of the traveling body 2 coincides or approximately coincides with the front-rear direction of the rotating body 3, and the width direction of the traveling body 2 coincides or approximately coincides with the width direction of the rotating body 3. In addition, FIG. 1 shows the crane 1 in a state in which the front side of the traveling body 2 coincides or approximately coincides with the front side (arrow X1 side) of the rotating body 3. In FIG. 1, each of the traveling body 2 and the rotating body 3 is shown as viewed from one side in the width direction.

[0014] In the traveling body 2, wheels 6 are attached to a body chassis 5. In the example of FIG. 1, a driver's cab 7 is provided in the traveling body 2, and the driver's cab 7 is arranged at the front end of the traveling body 2. In the example of FIG. 1, in the traveling body 2, the driver's cab 7 is located on the forward side with respect to each of the wheels 6 and the rotation axis P of the rotating body 3. In the driver's cab 7, operations for traveling the crane 1 including the traveling body 2 are input by an operator or the like.

[0015] Further, in the traveling body 2, two pairs of outriggers 8 are attached to the body chassis 5. In the traveling body 2, one pair of outriggers 8 is disposed at the front end, and another pair of outriggers 8 is disposed at the rear end. In the example of FIG. 1, in the traveling body 2, one pair of outriggers 8 is located forward of each of the wheels 6 and the rotation axis P of the rotating body 3, and another pair of outriggers 8 is located rearward of each of the wheels 6 and the rotation axis P of the rotating body 3. When performing work using the crane 1, each of the outriggers 8 is extended outward in the width direction of the traveling body 2, and each of the outriggers 8 is grounded on the ground.

[0016] In the crane 1, a boom unit 10 is attached to the rotating body 3. The boom unit 10 rotates together with the rotating body 3 relative to the traveling vehicle body 2. The boom unit 10 can be raised and lowered relative to the rotating body 3. The boom unit 10 is equipped with a multi-stage boom 11. The boom unit 10 and the multi-stage boom 11 have longitudinal directions (directions indicated by arrows C1 and C2). In the boom unit 10 and the multi-stage boom 11, one side in the longitudinal direction is the front side (the side indicated by arrow C1), and the side opposite the front side in the longitudinal direction is the rear side (the side indicated by arrow C2).

[0017] The boom unit 10 and the multi-stage boom 11 extend in the longitudinal direction from the front end to the rear end. In the boom unit 10, the rear end of the multi-stage boom 11 is attached to the revolving structure 3. When the boom unit 10 performs a hoisting operation, the boom unit 10 including the multi-stage boom 11 rotates about the attachment position to the revolving structure 3. Furthermore, the rotation axis of the boom unit 10 during the hoisting operation is along the width direction of the revolving structure 3. When the boom unit 10 is in a lowered state, the boom unit 10 protrudes from the revolving structure 3 to the front side of the revolving structure 3.

[0018] The crane 1 is also provided with a boom hoisting cylinder 12. One end of the boom hoisting cylinder 12 is connected to the rotating structure 3, and the other end is connected to the multi-stage boom 11 of the boom unit 10. The boom unit 10 performs a hoisting operation by driving the boom hoisting cylinder 12, which is a derrick cylinder, i.e., by extending or retracting the boom hoisting cylinder 12. The rotating structure 3 is also provided with an operation room (cab) 13. In the example shown in FIG. 1, the operation room 13 is arranged next to the boom unit 10 on one side in the width direction of the rotating structure 3. In the operation room 13, operations to be performed when the crane 1 is in operation, such as an operation to rotate the rotating structure 3, an operation to raise or lower the boom unit 10, and an operation to extend or retract the multi-stage boom 11 as described below, are input by an operator or the like.

[0019] FIG. 2 shows a schematic configuration of a boom unit according to this embodiment. As shown in FIG. 1 and FIG. 2, etc., in the boom unit 10, the multi-stage boom 11 includes a plurality of boom members Bi, and in the example shown in FIG. 1 and FIG. 2, the multi-stage boom 11 is a six-stage boom consisting of six boom members B1 to B6. In the multi-stage boom 11, each of the boom members Bi is extended along the longitudinal direction. Here, i indicates the stage number in the multi-stage boom 11, and when the multi-stage boom 11 has n stages, i is any natural number greater than or equal to 1 and less than or equal to n. As in the example shown in FIG. 1 and FIG. 2, in the six-stage multi-stage boom 11, the boom members B1, B2, B3, B4, B5, and B6 are the first stage, second stage, third stage, fourth stage, fifth stage, and sixth stage, respectively.

[0020] In the multi-stage boom 11, the first boom member B1 is the boom member in the rearmost stage, and its rear end is attached to the rotating body 3 as a base boom member. The boom members other than the base boom member (Bi other than B1) are movable boom members that can move in the longitudinal direction of the multi-stage boom 11 relative to the base boom. In the example of Figs. 1 and 2, boom members B2 to B6 are movable boom members, and five movable boom members are provided. In the example of Figs. 1 and 2, the sixth boom member B6 is the boom member in the final stage, and is the boom member in the foremost stage. In the following description, the boom member in the foremost stage is also referred to as boom member Bf.

[0021] Among the multiple boom members Bi, the first boom member B1 is disposed on the outermost side, and the last boom member Bf is disposed on the innermost side. Among the boom members Bi, the higher the stage number, the more inwardly they are disposed. In addition, in the multi-stage boom 11, the rear end is formed by the first boom member B1, and the front end is formed by the last boom member Bf. Note that in the following description, a six-stage multi-stage boom 11 provided with six boom members B1 to B6 is taken as an example, but the following configuration can be applied to any multi-stage boom 11 provided with multiple boom members Bi, that is, any multi-stage boom 11 provided with a base boom member and one or more movable boom members.

[0022] As shown in Fig. 2, in the boom unit 10, a boom telescopic drive unit 15 is disposed inside the multi-stage boom 11. The boom telescopic drive unit 15 is also referred to as a tele unit. Fig. 3 shows the boom telescopic drive unit 15, and Fig. 4 shows the internal configuration of the multi-stage boom 11 in the boom unit 10. Fig. 4 shows the rear end of the boom unit 10.

[0023] As shown in Figs. 2 to 4, the boom unit 10, the multi-stage boom 11, and the boom telescopic drive unit 15 are regulated by a width direction (indicated by arrows W1 and W2) that intersects (orthogonal or substantially orthogonal) with the longitudinal direction, and a height direction (indicated by arrows H1 and H2) that intersects both the longitudinal direction and the width direction. In Figs. 2 and 4, the boom unit 10 is shown in a cross section that is orthogonal or substantially orthogonal to the width direction. In addition, in the boom unit 10, the height direction coincides or substantially coincides with the hoisting direction in the hoisting operation. In addition, in the boom unit 10, the upper side in the height direction (the side of the arrow H1) corresponds to the side on which the boom unit 10 is raised, and the lower side in the height direction (the side of the arrow H2) corresponds to the side on which the boom unit 10 is lowered.

[0024] The boom telescopic drive unit 15 is equipped with a boom telescopic cylinder 16 which is a telecylinder. The boom telescopic cylinder 16 is equipped with a cylinder rod 17 and a cylinder tube 186. In the boom telescopic cylinder 16, the cylinder rod 17 and the cylinder tube 18 each extend along the longitudinal direction of the multi-stage boom 11. The cylinder tube 18 is movable along the longitudinal direction of the multi-stage boom 11 relative to the cylinder rod 17. The movement of the cylinder tube 18 relative to the cylinder rod 17 enables the boom telescopic cylinder 16 to telescope. The boom telescopic cylinder 16 extends or contracts with the telescopic direction aligned with the longitudinal direction of the multi-stage boom 11, and is driven to telescope.

[0025] In the example shown in Figures 2 to 4, a clevis portion 21 is formed at the rear end of the cylinder rod 17. The cylinder rod 17 is connected at the clevis portion 21 to a base boom member, which is the rearmost boom member B1. Also, in the boom telescopic cylinder 16, a trunnion block 22 is formed on the cylinder tube 18. The trunnion block 22 may be formed integrally with the cylinder tube 18, or may be attached to the cylinder tube 18. In the example shown in Figures 2 to 4, the trunnion block 22 is formed at the rear end of the cylinder tube 18.

[0026] When the boom telescopic cylinder 16 is driven to telescope, the trunnion block 22 moves together with the cylinder tube 18 in the telescopic direction of the boom telescopic cylinder 16 (the longitudinal direction of the multi-stage boom 11). As a result, when the boom telescopic cylinder 16 extends or retracts, the distance between the clevis portion 21 and the trunnion block 22 along the longitudinal direction of the multi-stage boom 11 changes. Note that regardless of the telescopic state of the boom telescopic cylinder 16, i.e., regardless of the telescopic state of the boom telescopic cylinder 16, the trunnion block 22 is located on the front side of the multi-stage boom 11 relative to the clevis portion 21. When the boom telescopic cylinder 16 is in the fully retracted state, the distance between the clevis portion 21 and the trunnion block 22 along the longitudinal direction of the multi-stage boom 11 becomes the smallest.

[0027] In addition, the boom telescopic drive unit 15 is provided with a guide plate 23, which guides the movement of the cylinder tube 18 along the longitudinal direction. In the example of Figs. 2 to 4, a pair of guide plates 23 is provided as the guide plate 23, and each of the guide plates 23 extends along the longitudinal direction of the boom telescopic drive unit 15 (multi-stage boom 11). The cylinder tube 18 is sandwiched between the pair of guide plates 23 in the width direction of the boom telescopic drive unit 15. In the example of Figs. 2 to 4, the trunnion block 22 is connected to each of the pair of guide plates 23, and with the trunnion block 22 connected to each of the guide plates 23, the trunnion block 22 and the cylinder tube 18 move along the longitudinal direction. Each of the guide plates 23 is formed over the entire length of the cylinder tube 18 in the longitudinal direction of the boom unit 10.

[0028] A grip member 25 such as a grip pin is attached to the trunnion block 22. The grip member 25 moves in the longitudinal direction of the multi-stage boom 11 together with the cylinder tube 18 and the trunnion block 22 in response to the telescopic drive of the boom telescopic cylinder 16. A grip hole J is provided at the rear end of each of the moving boom members, i.e., the second stage and the boom members B2 to Bf (B2 to B6 in this example) in the stage forward of the second stage, and the grip member 25 can engage with each of the grip holes J of the boom members B2 to Bf. In each of the boom members B2 to Bf, the grip member 25 engages with the grip hole J, thereby connecting the trunnion block 22 and the cylinder tube 18. In the following description, the grip holes J of the boom members B2, B3, B4, B5, and B6 are also referred to as grip holes J2, J3, J4, J5, and J6, respectively. The grip hole J of the boom member Bf in the most forward stage is also referred to as grip hole Jf.

[0029] The grip member 25 can be selectively engaged with one of the grip holes J2 to Jf of the movable boom member. Therefore, the trunnion block 22 (the cylinder tube 18 of the boom telescopic cylinder 16) can be selectively connected to one of the boom members B2 to Bf (B2 to B6 in this example) that are movable boom members via the grip member 25. In the state shown in FIG. 2, the grip member 25 is engaged with the grip hole J6 (Jf) of the boom member B6 (Bf), and the trunnion block 22 and the cylinder tube 18 are connected to the boom member B6. In FIG. 2, the grip hole J6 engaged with the grip member 25 is shown in black, and the grip holes J2 to J5 not engaged with the grip member 25 are shown in white dashed lines.

[0030] In addition, a locking member D such as a lock pin is attached to the rear end of each of the movable boom members, that is, the second stage and the boom members B2 to Bf (B2 to B6 in this example) in the stage in front of the second stage. Then, three locking holes Ea, Eb, Ec are formed in each of the boom members (Bi other than Bf) other than the final stage boom member Bf. In the example of Figs. 1 to 4, three locking holes Ea, Eb, Ec are formed in each of the boom members B1 to B5 except for the boom member B6. In each of the boom members B1 to B5, the locking hole Ea is formed in the rear end, the locking hole Eb is formed in the middle part in the longitudinal direction, and the locking hole Ec is formed in the front end. Therefore, in each of the boom members B1 to B5, the locking holes Ea, Eb, Ec are arranged apart from each other in the longitudinal direction of the multi-stage boom 11.

[0031] In the following description, the locking members D attached to the boom members B2, B3, B4, B5, and B6 are also referred to as locking members D2, D3, D4, D5, and D6, respectively. The locking member D attached to the frontmost boom member Bf is also referred to as locking member Df. The locking holes Ea of the boom members B1, B2, B3, B4, and B5 are also referred to as locking holes Ea1, Ea2, Ea3, Ea4, and Ea5, respectively, the locking holes Eb of the boom members B1, B2, B3, B4, and B5 are also referred to as locking holes Eb1, Eb2, Eb3, Eb4, and Eb5, respectively, and the locking holes Ec of the boom members B1, B2, B3, B4, and B5 are also referred to as locking holes Ec1, Ec2, Ec3, Ec4, and Ec5, respectively.

[0032] The locking member D of each of the boom members B2 to B6, which are movable boom members, can be selectively engaged with one of the three locking holes Ea, Eb, Ec of the boom member (corresponding one of B1 to B5) one step rearward. For example, the locking member D2 of the boom member B2 can be selectively engaged with one of the locking holes Ea1, Eb1, Ec1 of the boom member B1, and the locking member D6 of the boom member B6 (Bf) can be selectively engaged with one of the locking holes Ea5, Eb5, Ec5 of the boom member B5. Each of the boom members B2 to B6 is connected to the boom member (corresponding one of B1 to B5) one step rearward via the locking member D by the locking member D engaging with one of the locking holes Ea, Eb, Ec of the boom member (corresponding one of B1 to B5) one step rearward. In the state of Fig. 2 and the state of Fig. 4, the locking member D of each of the boom members B2 to B6 is engaged with the locking hole Ea of the boom member (corresponding one of B1 to B5) one stage rearward. In Fig. 2, the locking members D of each of the boom members B2 to B6 are shown painted black.

[0033] Furthermore, when the locking member D is not engaged with any of the lock holes Ea, Eb, Ec of the boom member (corresponding one of B1 to B5) one stage rearward, each of the boom members B2 to B6 is not connected to the boom member (corresponding one of B1 to B5) one stage rearward. When the locking member D is not engaged with any of the locking holes Ea, Eb, Ec of the boom member (corresponding one of B1 to B5) one stage rearward, each of the boom members B2 to B6 is movable along the longitudinal direction of the multi-stage boom 11 relative to the boom member (corresponding one of B1 to B5) one stage rearward.

[0034] Here, any one of the boom members B2 to B6, which are movable boom members, is designated as the boom member Bk, and the boom member Bk-1 is designated as the one stage behind the boom member Bk. k is any one of natural numbers between 2 and 6. When moving the boom member Bk-1, the grip member 25 of the boom telescopic drive unit 15 is engaged with the grip hole Jk of the boom member Bk, and the trunnion block 22 is connected to the boom member Bk. Then, with the trunnion block 22 connected to the boom member Bk, the lock member Dk of the boom member Bk is not engaged with any of the three lock holes Eak-1, Ebk-1, and Eck-1 of the boom member Bk-1, and the connection between the two boom members Bk and Bk-1 is released. Then, with the connection between the boom members Bk and Bk-1 released, the boom telescopic cylinder 16 is driven to telescopically extend and retract, and the boom member Bk is moved along the longitudinal direction relative to the boom member Bk-1. This causes the multi-stage boom 11 to perform an extension and contraction operation. When the boom member Bk is not the final stage, in a state in which the boom member Bk is moving relative to the boom member Bk-1, the boom members (Bk+1 to Bf) in the stage forward of the boom member Bk also move in the longitudinal direction together with the boom member Bk.

[0035] Furthermore, if the boom member Bk is not the final stage, in a state in which the multi-stage boom 11 is telescopically operated by the movement of the boom member Bk, the guide plate 23 can be fitted to the rear end of the boom member (Bk+1 to Bf) in the stage forward of the boom member Bk. As a result, in a state in which the multi-stage boom 11 is telescopically operated by the movement of the boom member Bk, the cylinder tube 18 is supported by the multi-stage boom 11 even in a portion forward of the trunnion block 22. Furthermore, in each of the boom members B2 to Bf, which are movable boom members, when the front end of the boom telescopic drive unit 15 is inserted into the interior from the rear side by the movement of the cylinder tube 18, the guide plate 23 prevents interference with the cylinder tube 18.

[0036] 5 to 12 show the trunnion block 22 and its vicinity in the boom telescopic drive unit 15. FIG. 5 to FIG. 7 are perspective views, and FIG. 6 is viewed from a different direction than FIG. 5 and FIG. 7. Also, FIG. 7 is viewed from the same or substantially the same direction as FIG. 5. FIG. 8 shows the boom unit 10 viewed from above in the height direction, and FIG. 9 shows the boom unit 10 viewed from one side in the width direction. FIG. 10 shows a cross section taken along line F1-F1 in FIG. 8, showing a cross section perpendicular or substantially perpendicular to the width direction of the boom unit 10. FIG. 11 and FIG. 12 show a cross section taken along line F2-F2 in FIG. 10, showing a cross section perpendicular or substantially perpendicular to the longitudinal direction of the boom unit 10 (the telescopic direction of the boom telescopic cylinder 16).

[0037] In the example of Figs. 3 to 12, a pair of grip members 25 are attached to the trunnion block 22 as the grip members 25. Each of the pair of grip members 25 has a central axis (not shown), and the central axis of each of the grip members 25 is along the width direction of the boom telescopic drive unit 15 (boom unit 10). Each of the grip members 25 can be changed between a stored state and a protruding state. In the stored state, each of the grip members 25 is stored inside the trunnion block 22 and does not protrude to the outside of the trunnion block 22. On the other hand, in the protruding state, each of the grip members 25 protrudes to the outside from the trunnion block 22. In the example of Figs. 3 to 12, each of the grip members 25 in the protruding state protrudes from the trunnion block 22 to the outside in the width direction of the boom telescopic drive unit 15. And, the pair of grip members 25 protrude from the trunnion block 22 on opposite sides to each other in the width direction.

[0038] Each of the grip members 25, in the protruding state, can be engaged with the grip hole J of any one of the boom members B2 to Bf, which are movable boom members. Therefore, the trunnion block 22 (cylinder tube 18) can be connected to any one of the boom members B2 to Bf via the grip member 25, in the protruding state of the grip member 25. On the other hand, each of the grip members 25, in the stored state, cannot be engaged with any of the grip holes J of the boom members B2 to Bf, which are movable boom members. Therefore, the trunnion block 22 (cylinder tube 18) is not connected to any of the boom members B2 to Bf, in the stored state of the grip member 25. Note that the grip members 25 are shown in the protruding state in each of Figs. 3, 5, 6, 8, and 11, and the grip members 25 are shown in the stored state in each of Figs. 7 and 12.

[0039] Further, a coil spring 26 is attached to the trunnion block 22 as a biasing member. In the example shown in Figs. 3 to 12, one coil spring 26 is provided corresponding to each of the pair of grip members 25, so that a pair of coil springs 26 is provided. An elastic force from the corresponding one of the pair of coil springs 26 acts on each of the pair of grip members 25 as a biasing force. Each of the grip members 25 is biased to a protruding state by the biasing force from the corresponding one of the coil springs 26. Therefore, each of the grip members 25 is in a protruding state when only the elastic force (biasing force) from the corresponding one of the coil springs 26 acts on each of the grip members 25.

[0040] Each of the coil springs 26 has one end connected to the trunnion block 22 and the other end connected to a corresponding one of the grip members 25. As in the example of Figs. 3 to 12, it is preferable that the central axis of each of the coil springs 26 is coaxial or approximately coaxial with the central axis of the corresponding one of the grip members 25. For this reason, in a preferred example such as the example of Figs. 3 to 12, the central axis of each of the coil springs 26 is aligned along the width direction of the boom telescopic drive unit 15 (boom unit 10). However, as long as the grip member 25 is biased to the protruding state by a biasing member such as the coil spring 26, the configuration is not limited to the example of Figs. 3 to 12.

[0041] Further, the boom telescopic drive unit 15 is provided with a grip drive cylinder 27, and in the example of Figs. 3 to 12, a pair of grip drive cylinders 27 are provided. Each of the grip drive cylinders 27 is disposed outside the trunnion block 22. In the example of Figs. 3 to 12, the trunnion block 22 is disposed between the pair of grip drive cylinders 27 in the height direction of the boom unit 10 (boom telescopic drive unit 15). Then, the grip drive cylinder 27α, which is one of the pair of grip drive cylinders 27, is adjacent to the trunnion block 22 from the upper side in the height direction, and the grip drive cylinder 27β, which is the other of the pair of grip drive cylinders 27, is adjacent to the trunnion block 22 from the lower side in the height direction.

[0042] In the example of Figs. 3 to 12, each of the grip drive cylinders 27 can be extended and retracted in the width direction of the boom telescopic drive unit 15. That is, the extension direction of each of the grip drive cylinders 27 is along the width direction. Each of the pair of grip members 25 is located between the pair of grip drive cylinders 27 in the height direction of the boom unit 10 (boom telescopic drive unit 15). Therefore, the grip drive cylinder 27α is located on the upper side of each of the grip members 25 in the height direction, and the grip drive cylinder 27β is located on the lower side of each of the grip members 25 in the height direction. One of the pair of grip members 25 is grip member 25A, and the other of the pair of grip members 25 is grip member 25B. Each of the pair of grip drive cylinders 27 is connected to the grip member 25A and is also connected to the grip member 25B.

[0043] In the example of Figs. 3 to 12, four link members 28 are provided on the boom telescopic drive unit 15. The four link members 28 are also referred to as link members 28Aα, 28Aβ, 28Bα, and 28Bβ. The grip drive cylinder 27α is connected to the grip member 25A through the link member 28Aα, and is connected to the grip member 25B through the link member 28Bα. The grip drive cylinder 27β is connected to the grip member 25A through the link member 28Aβ, and is connected to the grip member 25B through the link member 28Bβ. In addition, the link member 28Aα is connected to one end of the grip drive cylinder 27α in the width direction of the boom telescopic drive unit 15, and the link member 28Bα is connected to the end of the boom telescopic drive unit 15 on the opposite side to the side to which the link member 28Aα is connected in the width direction. In the grip drive cylinder 27β, a link member 28Aβ is connected to one end of the boom extension and telescopic drive unit 15 in the width direction, and a link member 28Bβ is connected to an end of the boom extension and telescopic drive unit 15 on the opposite side in the width direction to the side to which the link member 28Aβ is connected.

[0044] In the example of Fig. 3 to Fig. 12, a pair of shaft members 31 are attached to the trunnion block 22, and the pair of shaft members 31 are also indicated as shaft members 31A and 31B. Each of the shaft members 31 extends along the height direction of the boom telescopic drive unit 15 and penetrates the trunnion block 22 in the height direction. The pair of shaft members 31 are located apart from each other in the width direction of the boom telescopic drive unit 15. In the example of Fig. 3 to Fig. 12, the link members 28Aα and 28Aβ are attached to the trunnion block 22 via the shaft member 31A and are connected to each other via the shaft member 31A. And the link members 28Bα and 28Bβ are attached to the trunnion block 22 via the shaft member 31B and are connected to each other via the shaft member 31B. In addition, the link members 28Aα and 28Aβ are rotatable about the shaft member 31A, and the link members 28Bα and 28Bβ are rotatable about the shaft member 31B. Therefore, the rotation axes of the link members 28 are aligned along the height direction of the boom extension and contraction drive unit 15.

[0045] Each of the link members 28 is connected at one end to a corresponding one of the grip drive cylinders 27. Then, in each of the link members 28, a corresponding one of the grip members 25 is connected at an end opposite to the side to which the corresponding one of the grip drive cylinders 27 is connected. Therefore, in each of the link members 28, a corresponding one of the shaft members 31 is connected between a connection position of the corresponding one of the grip drive cylinders 27 and a connection position of the corresponding one of the grip members 25. That is, in each of the link members 28, a rotation axis is located between a connection position of the corresponding one of the grip drive cylinders 27 and a connection position of the corresponding one of the grip members 25.

[0046] In the example of Figs. 3 to 12, each of the grip drive cylinders 27 is disposed on the front side of the boom telescopic drive unit 15 with respect to each of the grip members 25. Therefore, in each of the link members 28, the connection position of the corresponding one of the grip drive cylinders 27 is located on the front side with respect to the rotation shaft (shaft member 31), and the connection position of the corresponding one of the grip members 25 is located on the rear side with respect to the rotation shaft (shaft member 31). Note that in the example of Figs. 3 to 12, one pin member 32 is provided in the boom telescopic drive unit 15 corresponding to each of the four link members 28, and four pin members 32 are provided. Each of the link members 28 is connected to a corresponding one of the grip members 25 via a corresponding one of the pin members 32.

[0047] 3 to 12, in one example, each of the grip drive cylinders 27 is disposed on the rear side of the boom telescopic drive unit 15 with respect to each of the grip members 25. In this case, in each of the link members 28, a connection position of one corresponding one of the grip drive cylinders 27 is located on the rear side with respect to the rotation shaft (shaft member 31). And, in each of the link members 28, a connection position of one corresponding one of the grip members 25 is located on the front side with respect to the rotation shaft (shaft member 31).

[0048] In this embodiment, a cylinder connecting member 33 such as a cylinder connecting pin is provided to the boom extension and telescopic drive unit 15. In the boom extension and telescopic drive unit, the pair of grip drive cylinders 27 are connected by the cylinder connecting member 33. In the example of Figures 3 to 12, two cylinder connecting members 33 are provided, and the two cylinder connecting members 33 are also referred to as cylinder connecting members 33A and 33B, respectively.

[0049] Each cylinder connecting member 33 extends along the height direction of the boom telescopic drive unit 15, and the two cylinder connecting members 33 are positioned apart from each other in the width direction of the boom telescopic drive unit 15. In the grip drive cylinder 27α, the cylinder connecting member 33A is connected to the end on the side where the link member 28Aα is connected in the width direction, and the cylinder connecting member 33B is connected to the end on the side where the link member 28Bα is connected in the width direction. In the grip drive cylinder 27β, the cylinder connecting member 33A is connected to the end on the side where the link member 28Aβ is connected in the width direction, and the cylinder connecting member 33B is connected to the end on the side where the link member 28Bβ is connected in the width direction.

[0050] Figures 13 and 14 show schematic diagrams of a mechanism for operating the grip members 25 by driving the grip drive cylinders 27. Figures 13 and 14 show cross sections perpendicular or substantially perpendicular to the height direction of the boom telescopic drive unit 15. Also, in Figure 13, the grip members 25 are shown in a protruding state, while in Figure 14, the grip members 25 are shown in a stored state. In the example shown in Figures 3 to 14, each of the grip drive cylinders 27 is hydraulically extended by being supplied with hydraulic oil. That is, each of the grip drive cylinders 27 is hydraulically extended (driven).

[0051] In a state where hydraulic oil is not supplied to each of the grip drive cylinders 27, only an elastic force (biasing force) from one of the corresponding coil springs 26 acts on each of the grip members 25. Therefore, each of the grip members 25 is maintained in a protruding state by the biasing force from the coil spring 26, which is a biasing member. In addition, a force is transmitted from the coil spring 26 to each of the grip drive cylinders 27 via the grip members 25 and the link member 28. Therefore, a force in the contracting direction acts on each of the grip drive cylinders 27 by the force from the coil spring 26. In a state where hydraulic oil is not supplied to each of the grip drive cylinders 27, no hydraulic pressure or the like acts, and only a force in the contracting direction acts. Therefore, each of the grip drive cylinders 27 is maintained in a contracted state unless hydraulic oil is supplied.

[0052] In the example shown in Figs. 3 to 14, each of the grip drive cylinders 27 is hydraulically extended by being supplied with hydraulic oil. When each of the grip drive cylinders 27 is extended, each of the link members 28 rotates about the rotation axis. As a result, a force is transmitted from the grip drive cylinder 27 to each of the grip members 25 via the link members 28. Each of the grip members 25 changes from the protruding state to the stored state against the bias from the corresponding one of the coil springs 26 by the force transmitted from the grip drive cylinder 27. Therefore, when the grip drive cylinder 27 is extended (driven) by hydraulic pressure or the like, each of the grip members 25 changes to the stored state against the elastic force (biasing force) from the coil spring 26, which is a biasing member.

[0053] 3 to 14, when the grip drive cylinder 27 is driven to extend, each of the grip members 25 changes to a stored state against the bias from the coil spring 26, which is a biasing member. However, in one example, each of the grip drive cylinders 27 may be hydraulically contracted by supplying hydraulic oil. In this case, when the grip drive cylinder 27 is driven to contract, each of the grip members 25 changes from a protruding state to a stored state against the bias from the coil spring 26, which is a biasing member.

[0054] As shown in FIG. 4 and other figures, a coil spring 37, which is a biasing member, is attached to each of the locking members D of the boom members B2 to B6, which are movable boom members. An elastic force from the coil spring 37 acts as a biasing force on each of the locking members D of the boom members B2 to B6. Each of the locking members D of the boom members B2 to B6 is biased toward the outside of the multi-stage boom 11 by the elastic force from the coil spring 37. In the example of FIG. 3 to FIG. 12, each of the locking members D of the boom members B2 to B6 is biased toward the upper side in the height direction of the multi-stage boom 11 by the elastic force from the coil spring 37. In a state in which the locking member Dk of the boom member Bk is engaged with any one of the three lock holes Eak-1, Ebk-1, and Eck-1 of the boom member Bk-1, the engagement between the locking member Dk of the boom member Bk and the boom member Bk-1 is maintained by the bias from the coil spring 37 unless an external force or the like acts. Therefore, unless an external force or the like is applied, the connection between the two boom members Bk, Bk-1 is maintained by the biasing force from the coil spring 37.

[0055] In the boom telescopic drive unit 15 of this embodiment, as shown in Figs. 3 to 12, the lock drive cylinder 35 is attached to the trunnion block 22. In the example of Figs. 3 to 12, two lock drive cylinders 35 are attached to the trunnion block 22. In addition, the engagement plate 36 is connected to the trunnion block 22 with the lock drive cylinder 35 interposed therebetween. The lock drive cylinder 35 and the engagement plate 36 move in the longitudinal direction of the multi-stage boom 11 together with the cylinder tube 18 and the trunnion block 22 in response to the telescopic drive of the boom telescopic cylinder 16. In addition, each of the lock drive cylinders 35 is telescopic, and in the example of Figs. 3 to 12, the telescopic direction of each of the lock drive cylinders 35 is along the height direction of the boom unit 10 (boom telescopic drive unit 15). By extending or retracting the lock drive cylinder 35, the engagement plate 36 moves along the height direction of the boom unit 10.

[0056] The engagement plate 36 moves in the longitudinal direction in accordance with the telescopic drive of the boom telescopic cylinder 16, and can selectively engage with one of the lock members D2 to D6 (D2 to Df) of the movable boom member. When the engagement plate 36 engages with the lock member Dk of the boom member Bk, the lock drive cylinder 35 is connected to the lock member Dk via the engagement plate 36. Therefore, when the lock member Dk of the boom member Bk engages with the engagement plate 36, the force from the lock drive cylinder 35 can be transmitted to the lock member Dk.

[0057] In the example of Figs. 3 to 12, each of the lock drive cylinders 35 is hydraulically contracted by being supplied with hydraulic oil. When each of the lock drive cylinders 35 is driven (operated) to contract while connected to the lock member Dk, the force from the lock drive cylinders 35 is transmitted to the lock member Dk via the engagement plate 36. Due to the force transmitted from the lock drive cylinders 35, the lock member Dk moves toward the inside of the multi-stage boom 11 against the elastic force (biasing force) from the coil spring 37. At this time, in the example of Figs. 3 to 12, the lock member Dk moves downward in the height direction of the multi-stage boom 11 against the biasing force from the coil spring 37 which is a biasing member.

[0058] In a state where the locking member Dk of the boom member Bk is engaged with any one of the three locking holes Eak-1, Ebk-1, and Eck-1 of the boom member Bk-1, the locking member Dk of the boom member Bk moves inward by the force transmitted from the lock driving cylinder 35, thereby disengaging the locking member Dk of the boom member Bk from the boom member Bk-1. Therefore, the locking member Dk moves inward against the biasing force by the force from the lock driving cylinder 35, thereby disengaging the connection between the two boom members Bk and Bk-1. As described above, in this embodiment, the locking member Dk is driven (retracted) in a state where it is connected to the locking member Dk, thereby switching the connection state between the two boom members Bk and Bk-1 by the locking member Dk.

[0059] 3 to 12, each of the grip members 25 is located between the grip drive cylinder 27 and the lock drive cylinder 35 in the extension / retraction direction of the boom telescopic cylinder 16 (the longitudinal direction of the boom unit 10). Each of the lock drive cylinders 35 is located on the rear side of the boom unit 10 (boom telescopic drive unit 15) with respect to the grip members 25, and each of the grip drive cylinders 27 is located on the front side of the boom unit 10 with respect to the grip members 25.

[0060] The positional relationship between the grip member 25, the grip drive cylinder 27, and the lock drive cylinder 35 is not limited to the example of Figures 3 to 12. However, in this embodiment, similar to the example of Figures 3 to 12, it is preferable that the grip member 25 is located between the grip drive cylinder 27 and the lock drive cylinder 35 in the extension and retraction direction of the boom telescopic cylinder 16.

[0061] Furthermore, when the grip member 25 is located between the grip drive cylinder 27 and the lock drive cylinder 35, it is more preferable that the lock drive cylinder 35 is located on the rear side with respect to the grip member 25, and the grip drive cylinder 27 is located on the front side with respect to the grip member 25, as in the example of Figures 3 to 12. However, in one example, in a configuration in which the grip member 25 is located between the grip drive cylinder 27 and the lock drive cylinder 35, the lock drive cylinder 35 may be located on the front side with respect to the grip member 25, and the grip drive cylinder 27 may be located on the rear side with respect to the grip member 25.

[0062] 3 to 12, four recesses 38 are formed in the trunnion block 22. Two recesses 38 are formed in the upper surface of the trunnion block 22 facing upward in the height direction, and the remaining two recesses 38 are formed in the lower surface of the trunnion block 22 facing downward in the height direction. In the upper surface of the trunnion block 22, each of the two recesses 38 is recessed downward in the height direction, and in the lower surface of the trunnion block 22, each of the two recesses 38 is recessed upward in the height direction. In the example of FIGS. 3 to 12, each of the four link members 28 is disposed in a corresponding one of the four recesses 38.

[0063] In addition, in one example, the recess 38 does not have to be formed in the trunnion block 22. However, even in this case, the grip drive cylinder 27 and the link member 28 are each disposed outside the trunnion block 22.

[0064] In this embodiment, as described above, the grip drive cylinder 27 is disposed outside the trunnion block 22. Since the grip drive cylinder 27 is not built into the trunnion block 22, there is no need to ensure a space for arranging the grip drive cylinder 27 inside the trunnion block 22. Furthermore, since the grip drive cylinder 27 is not built into the trunnion block 22, there is no need to build a boss or the like for filling the gap between the trunnion block 22 and the grip drive cylinder 27 inside the trunnion block 22. This makes it possible to reduce the volume of the trunnion block 22, and makes it possible to reduce the size and weight of the trunnion block 22.

[0065] The weight reduction of the trunnion block 22 allows the entire boom telescopic drive unit 15 to be lighter. Furthermore, the reduction in the volume of the trunnion block 22 allows the volume of the trunnion block 22 to be reduced in the longitudinal direction of the boom unit 10 (the direction in which the boom telescopic cylinder 16 extends and retracts), the width direction of the boom unit 10, and the height direction of the boom unit 10. The reduction in the dimension of the trunnion block 22 in the direction in which the boom telescopic cylinder 16 extends and retracts makes it possible to suppress an increase in the dimension (total length) of the boom telescopic drive unit 15 in the direction in which the boom telescopic cylinder 16 extends and retracts.

[0066] Furthermore, by reducing the dimension of the trunnion block 22 in the height direction of the boom unit 10, it is possible to reduce the dimension of each of the guide plates 23 with which the trunnion block 22 engages in the height direction of the boom unit 10. By reducing the dimension of each of the guide plates 23 in the height direction of the boom unit 10, the guide plates 23 are lighter, and the entire boom telescopic drive unit 15 is further lighter.

[0067] In addition, in this embodiment, the boss and the grip drive cylinder 27 are not built into the trunnion block 22, which makes it possible to simplify the shape of the trunnion block 22. By simplifying the shape of the trunnion block 22, the effort and cost required for processing the trunnion block 22 can be reduced.

[0068] Moreover, in one example of this embodiment, each of the coil springs 26 is directly connected to a corresponding one of the grip members 25, and the central axis of each of the coil springs 26 is coaxial or approximately coaxial with the central axis of the corresponding one of the grip members 25. Therefore, the elastic force (biasing force) from the corresponding one of the coil springs 26 acts evenly on each of the grip members 25. As a result, each of the grip members 25 is appropriately maintained in a protruding state in a state where only the elastic force (biasing force) from the corresponding one of the coil springs 26 acts on each of the grip members 25.

[0069] Moreover, in one example of this embodiment, each of the pair of grip drive cylinders 27 is connected to a grip member 25. The grip member 25 is located between the pair of grip drive cylinders 27 in the height direction of the multi-stage boom 11, and the pair of grip drive cylinders 27 are connected by a cylinder connecting member 33. With this configuration, the pair of grip drive cylinders 27 are synchronously driven (extended) so that the force from the grip drive cylinders 27 acts evenly on each of the grip members 25. As a result, each of the grip members 25 smoothly and appropriately changes from the extended state to the stored state by the force from the grip drive cylinder 27.

[0070] Also, in this embodiment, since no boss is built into the trunnion block 22, the lock drive cylinder 35 can be disposed in a position close to the grip member 25 in the trunnion block 22, making it possible to reduce the distance between the grip member 25 and the boom telescopic cylinder 16 in the telescopic direction of the boom telescopic cylinder 16 (the longitudinal direction of the boom unit 10). By reducing the distance between the grip member 25 and the boom telescopic cylinder 16 in the telescopic direction of the boom telescopic cylinder 16, the dimension of the boom telescopic drive unit 15 in the longitudinal direction of the boom unit 10 can be further reduced.

[0071] In a preferred example of this embodiment, the grip member 25 is located between the grip drive cylinder 27 and the lock drive cylinder 35 in the telescopic direction of the boom telescopic cylinder 16. This arrangement makes it possible to reduce the dimension of the trunnion block 22 along the telescopic direction of the boom telescopic cylinder 16, and further reduce the dimension (total length) of the boom telescopic drive unit 15 along the telescopic direction of the boom telescopic cylinder 16. In addition, in a configuration in which the grip member 25 is located between the grip drive cylinder 27 and the lock drive cylinder 35, by positioning the lock drive cylinder 35 on the rear side of the grip member 25 and positioning the grip drive cylinder 27 on the front side of the grip member 25, the dimension (total length) of the boom telescopic drive unit 15 along the telescopic direction of the boom telescopic cylinder 16 can be further reduced.

[0072] Moreover, in one example of this embodiment, four recesses 38 are formed in the trunnion block 22, and each of the four link members 28 is disposed in a corresponding one of the four recesses 38. This allows each of the link members 28 to be disposed in a position close to the grip member 25. By disposing each of the link members 28 in a position close to the grip member 25, an increase in the weight of the pin member 32 connecting each of the link members 28 and the corresponding one of the grip members 25 can be suppressed.

[0073] (Modification) In the above-described embodiment, the two grip members 25 are attached to the trunnion block 22, and the boom telescopic drive unit 15 is provided with a pair of grip drive cylinders 27, but it is sufficient to provide at least one each of the grip members 25 and the grip drive cylinders 27. In either case, however, the grip drive cylinder 27 is connected to the grip members 25 while positioned outside the trunnion block 22. When the grip drive cylinder 27 is driven, the grip members 25 change from the protruding state to the stored state against the biasing force from the biasing member such as the coil spring 26.

[0074] In addition, in the above-mentioned embodiments, etc., a six-stage multi-stage boom is provided with five boom members B2 to B6 that serve as movable boom members, but the configurations of the above-mentioned embodiments, etc. can be applied to a two-stage or more multi-stage boom that includes a base boom member and one or more movable boom members. Also, in construction machines other than cranes, the configurations of the above-mentioned embodiments, etc. can be applied to the boom unit as long as the machine is configured to include a boom unit that includes a multi-stage boom and a boom telescopic drive unit.

[0075] The present invention is not limited to the above-mentioned embodiment, and various modifications can be made in the implementation stage without departing from the gist of the invention. The embodiments may be implemented in combination as appropriate as possible, and in that case, the combined effects can be obtained. Furthermore, the above-mentioned embodiment includes inventions at various stages, and various inventions can be extracted by appropriate combinations of the disclosed constituent elements. [Explanation of symbols]

[0076] 1...crane, 2...running body, 3 rotating body, 10...boom unit, 11...multi-stage boom, 15...boom telescopic drive unit, 16...boom telescopic cylinder, 17...cylinder rod, 18...cylinder tube, 21...clevis portion, 22...trunnion block, 25 (25A, 25B)...grip member, 26...coil spring, 27 (27α, 27β)...grip drive cylinder, 28 (28Aα, 28Aβ, 28Bα, 28Bβ)...link member, 31 (31A, 31B)...shaft member, 33 (33A, 33B)...cylinder connecting member, 35...lock drive cylinder, B1 to B6...boom member, D2 to D6...lock member.

Claims

1. A multi-stage boom includes a base boom member and one or more movable boom members movable relative to the base boom member as boom members, the multi-stage boom having a boom telescopic drive unit that telescopically operates the multi-stage boom, a boom telescopic cylinder including a cylinder rod connected to the base boom member and a cylinder tube movable relative to the cylinder rod, the boom telescopic cylinder being extendable and retractable by movement of the cylinder tube; a trunnion block movable together with the cylinder tube; a grip member attached to the trunnion block so as to be changeable between a stored state in which the trunnion block is stored and a protruding state in which the trunnion block protrudes, and in the protruding state, the grip member enables the trunnion block to be connected to any one of the one or more moving boom members; a biasing member that biases the gripping member to the protruding state; a grip drive cylinder that is connected to the grip member while being positioned outside the trunnion block and that is driven to change the grip member to the stored state against the biasing force from the biasing member; A boom telescopic drive unit comprising:

2. In the protruding state, the grip member protrudes from the trunnion block to the outside in a width direction intersecting with the telescopic direction of the boom telescopic cylinder, The grip drive cylinder extends and retracts along the width direction.

2. The boom extension and retraction drive unit of claim 1.

3. The grip actuation cylinder includes a pair of grip actuation cylinders each connected to the grip member, The grip member is located between the pair of grip drive cylinders in a height direction intersecting both the extension and retraction direction and the width direction of the boom telescopic cylinder, Further comprising a cylinder connecting member connecting the pair of grip drive cylinders.

3. The boom extension and retraction drive unit according to claim 2.

4. In the multi-stage boom, each of the one or more movable boom members can be connected to a boom member of a rear stage by only one stage via a lock member, a lock drive cylinder attached to the trunnion block and driven in a state connected to the lock member to switch a connection state between the two boom members by the lock member; The grip member is located between the grip drive cylinder and the lock drive cylinder in the extension and retraction direction of the boom telescopic cylinder.

2. The boom extension and retraction drive unit of claim 1.

5. The lock drive cylinder is located rearward relative to the grip member, The grip drive cylinder is located forward of the grip member.

5. The boom extension and retraction drive unit according to claim 4.

6. A boom extension and contraction drive unit according to any one of claims 1 to 5, a multi-stage boom including the base boom member and the one or more movable boom members as the boom members, the multi-stage boom performing the telescopic operation by the boom telescopic drive unit; A boom unit comprising:

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