JP2019120087A - Clamshell bucket - Google Patents

Abstract

To provide a clamshell bucket that ensures an earth removal property and sufficient strength and in which an increase in weight is restricted.SOLUTION: A pair of buckets 19, 24 of a clamshell bucket 11 are composed of: bottom plates 20, 25, the front end sides of which are sediment outflow/inflow openings 20A, 25A to receive sediments flowing inside in the closed position; a pair of side plates 21, 26 that are provided on both the widthwise ends of the bottom plates 20, 25 respectively and that face each other; and sediment storage spaces S1, S2 that are formed in an inner space surrounded by the bottom plates 20, 25 and the pair of side plates 21, 26. The bottom plates 20, 25 of the buckets 19, 24 are composed of: curved parts 20B, 25B extending from the sediment outflow/inflow openings 20A, 25A in a convex manner; and bent parts 20C, 25C that are provided on the rear end sides of the curved parts 20B, 25B located on the opposite side to the sediment outflow/inflow openings 20A, 25A and that bend toward a direction away from a rotation fulcrum O.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a clamshell bucket provided in a construction machine for drilling a shaft.

  In general, a shaft drilling machine is preferably used when drilling a shaft on the ground. This shaft drilling machine has a self-propelled lower traveling unit, an upper revolving unit pivotally mounted on the lower traveling unit, and a multi-stage expansion and contraction vertically extendable and downwardly on the front side of the upper revolving unit. A work apparatus of the formula (telescopic type) and a clamshell bucket provided on the lower end side of the work apparatus are provided.

  Here, the clamshell bucket has a pair of buckets that can be opened and closed between an open position spaced apart from each other and a closed position moved closer to each other about their respective pivot points. In these buckets, the front end side (one end side) is a sediment inflow opening at the closed position, and a bottom plate for receiving the sand that has flowed into the inside at the closed position, and a pair of side plates provided on both ends in the width direction of the bottom plate And a sediment storage space formed in the interior surrounded by the bottom plate and the pair of side plates (see, for example, Patent Document 1).

JP, 2013-221284, A

  By the way, in the clamshell bucket described in Patent Document 1, a reinforcing plate is fixed to the rear end side of the bottom plate to improve the strength of the bottom plate and the side plate. Here, the drilling capacity of the shaft drilling machine is determined by the total weight of the weight of the clamshell bucket and the weight of earth and sand provided by the clamshell bucket. Therefore, when the weight of the entire clamshell bucket is increased by the reinforcing plate, there is a problem that the digging capacity of the clamshell bucket is reduced. Also, for example, when soil (water, clay, etc.) containing water is pressed into the corner between the reinforcing plate and the bottom plate and the soil becomes compacted, the soil may stick to the corner and the soilability may deteriorate. There is.

  The present invention has been made in view of the above-described problems of the prior art, and an object of the present invention is to provide a clamshell bucket in which an increase in weight is suppressed while securing earthiness and sufficient strength. .

  The present invention has a pair of buckets provided in a working device of a construction machine, which can be opened and closed between an open position spaced apart from each other with respect to their respective pivot points and a closed position approaching each other. A bottom plate having a sediment inflow opening at the front end side and receiving sediment flowing into the inside at the closed position, a pair of side plates provided at both ends in the width direction of the bottom plate, the bottom plate and the pair of side plates And the bottom plate of the bucket includes a curved portion extending in a convex shape from the inflow / outflow opening and the inflow / outflow opening It is characterized in that it comprises a bent portion provided on the rear end side of the curved portion located on the opposite side and bent in a direction away from the pivot.

  According to the present invention, it is possible to secure sufficient strength while suppressing the earthiness and weight increase of the clamshell bucket.

It is a front view showing a shaft drilling machine provided with a clamshell bucket concerning a 1st embodiment of the present invention. It is a front view which expands and shows the clamshell bucket in FIG. It is a front view shown in the state which made each bucket of the clamshell bucket in FIG. 2 a closed position. It is sectional drawing which expands and shows the clamshell bucket in FIG. 3 from the arrow IV-IV direction. It is a front view of the partially broken view which expands and shows the bending part of the baseplate of the clamshell bucket in FIG. It is a front view which shows the bending part of the baseplate of the clamshell bucket by 2nd Embodiment of this invention.

  Hereinafter, as a construction machine according to an embodiment of the present invention, a vertical excavation machine provided with a clamshell bucket in a multistage telescopic type working device will be described as an example and explained in detail according to the attached drawings.

  1 to 5 show a first embodiment of the present invention. The shaft drilling machine 1 has a car body comprising a self-propelled crawler type lower traveling unit 2 and an upper revolving unit 3 rotatably mounted on the lower traveling unit 2. A multistage telescopic type working device 7 is provided on the front side of the upper swing body 3 so as to be telescopically extendable in the upper and lower directions, and a pit P can be excavated on the ground G using this working device 7 .

  The upper swing body 3 is provided on a swing frame 4 forming a support structure, a counterweight 5 provided at the rear of the swing frame 4 to balance the weight with the work device 7, and a left front portion of the swing frame 4 And a cab 6 on which an operator boardes. Inside the cab 6, a driver's seat, a control lever for operation, and a control lever / pedal for traveling are disposed.

  The work device 7 excavates the earth and sand in the deep area of the column P, for example, the boom 7A rotatably attached to the front side of the turning frame 4 and the tip side of the boom 7A turn forward and backward It is configured to include a multistage telescopic arm 7B movably attached and a clamshell bucket 11 described later attached to the tip of the multistage telescopic arm 7B.

  Next, the clamshell bucket 11 of the present invention will be described. The lower side of the drawing in FIG. 2 will be described as the front side of the clamshell bucket 11, and the upper side of the drawing will be described as the rear side of the clamshell bucket 11. Further, with the left and right directions in the drawing of FIG. 2 as the open / close direction of the clamshell bucket 11, the depth direction in the drawing of FIG. The description is given as left and right directions (width direction).

  The clamshell bucket 11 is attached to the tip of the multistage telescopic arm 7B. The clamshell bucket 11 has a pair of buckets 19 and 24 connected openably and closably, and excavates earth and sand by opening and closing the pair of buckets 19 and 24 by the actuator 13. The clamshell bucket 11 is configured to include the bucket support member 12, the actuator 13, the soil removing device 17, and the buckets 19 and 24.

  The bucket support member 12 is a structure serving as a core of the clamshell bucket 11. The bucket support member 12 is reversed by a rod portion 12A consisting of a cylindrical body extending upward and downward and a cross beam portion 12B located at the lower end of the rod portion 12A and extending orthogonal to the width direction of the clamshell bucket 11 It is formed as a T-shaped structure.

  The rod portion 12A also serves as a rod of an actuator 13 described later, and a piston (not shown) of the actuator 13 is integrally attached in the middle in the length direction. The tube 13A of the actuator 13 is provided on the outer peripheral side of the rod portion 12A so as to be movable upward and downward so as to surround the piston. Further, an arm attaching portion 12C attached to the multistage telescopic arm 7B is provided on the upper portion of the rod portion 12A.

  As shown in FIGS. 2 to 4, the cross beam portion 12B is formed as a rectangular cylinder extending in the width direction (left and right directions), and bucket mounting plates 12D are respectively provided at both ends in the width direction. Bucket attachment parts 12D1 to which buckets 19 and 24 described later are rotatably attached are respectively provided on both end sides of each bucket attachment plate 12D in the opening and closing direction.

  The actuator 13 is configured as a double rod hydraulic cylinder provided between the bucket support member 12 and a pair of buckets 19 and 24 described later. The actuator 13 rotates the buckets 19 and 24 upward to open the outflow / inflow openings 20A and 25A apart from each other (the position shown in FIG. 2), and rotates the buckets 19 and 24 downward to flow out The entrances 20A and 25A open and close between closed positions (positions in FIG. 3) close to each other.

  The actuator 13 includes a rod portion 12A of the bucket support member 12, a cylindrical tube 13A provided movable upward and downward on the outer peripheral side of the rod portion 12A, an upper oil chamber and a lower oil in the tube 13A. It comprises a piston (not shown) integrally attached to the rod portion 12A so as to define a chamber.

  The actuator 13 is provided with a pair of link mounting brackets 13B (only one of which is shown) radially projecting from the tube 13A in a symmetrical manner in the opening and closing direction. A hydraulic hose (not shown) is connected to the actuator 13, and pressure oil is supplied (supplied / discharged) to the upper oil chamber and the lower oil chamber in the tube 13A, whereby the rod portion 12A of the bucket support member 12 is provided. In contrast, the tube 13A can be moved up and down.

  The link 14 is provided between each of the buckets 19 and 24 to be described later and the actuator 13. The link 14 is formed as a triangular structure having a narrow width on the tube 13A side in the width direction (left and right directions) and a wide width on the buckets 19 and 24 (lower side). Each link 14 is rotatably connected to the link mounting bracket 13B of the actuator 13 using the connecting pin 15 and can be rotated using the connecting pin 16 to the pair of link mounting portions 21D and 26D of the buckets 19 and 24. Are linked to each other.

  Therefore, when the tube 13A of the actuator 13 is moved along the rod portion 12A toward the arm mounting portion 12C, the links 14 rotate the buckets 19 and 24 toward the open position shown in FIG. On the other hand, when the tube 13A is moved to the cross beam 12B, the links 14 rotate the buckets 19 and 24 toward the closed position shown in FIG.

  The pair of earth removing devices 17 and 18 are provided in the cross beam portion 12B of the bucket support member 12 so as to be located in the below-described buckets 19 and 24 (earth and sand storage spaces S1 and S2). One of the earth removing devices 17 is provided in a bucket 19 described later, and removes clay, mud and the like stuck to the bottom plate 20 when the bucket 19 is opened from the closed position to the open position. The other earth removing device 18 is provided in a bucket 24 described later, and scrapes clay, mud and the like stuck to the bottom plate 25 when the bucket 24 is opened from the closed position to the open position.

  As shown in FIGS. 2 to 4, the soil removing device 17 includes a pair of soil removing device attachment portions 17A provided on the cross beam portion 12B across the rod portion 12A of the bucket support member 12 and a pair of soil removing devices attached A pair of L-shaped plates 17B extending from the portion 17A toward the outer side in the opening / closing direction (bottom plate 20 side) and bent toward the outer side in the width direction (side plate 21 side) at a position beyond the connecting pin 16; It is fixed to the tip of the plate 17B and is formed in a frame shape by a scraping plate 17C extending in the width direction between the side plates 21.

  The scraping plate 17C of the soil removing device 17 is close to the inner surface of the bottom plate 20 of the bucket 19 and moves relative to the bottom plate 20 of the bucket 19. As a result, when the bucket 19 rotates (moves) from the closed position to the open position, it contacts soil such as clay or mud stuck to the inner surface of the bottom plate 20 of the bucket 19 and sticks to the inner surface of the bottom plate 20 Sand and sand can be scraped off. On the other hand, the earth removal device 18 is provided in the other bucket 24 described later, and like the earth removal device 17, it has a frame shape by a pair of earth removal device attachment parts 18A, a pair of L-shaped plates 18B, and a scraping plate 18C. Is formed.

  Next, a pair of buckets 19 and 24 which store sand inside will be described.

  The pair of buckets 19 and 24 are disposed symmetrically with respect to the cross beam portion 12B of the bucket support member 12. Since the bucket 19 and the bucket 24 have the same shape and configuration, the bucket 19 will be described in detail below.

  The front end side (one end side) of the bucket 19 is a sediment inflow opening 20A at the front end side (bottom end), and the bottom plate 20 receives the earth and sand flowing into the inside at the closed position (state of FIG. 3) And a sediment storage space S1 (see FIGS. 4 and 5) formed inside surrounded by the bottom plate 20 and the pair of side plates 21. As shown in FIG.

  As shown in FIG. 3, each side plate 21 of the bucket 19 has a thickness fixed to the thin plate portion 21A so as to surround the thin plate portion 21A to which the bottom plate 20 is fixed at the outer end portion and the inner end portion of the thin plate portion 21A. It is comprised including board part 21B. That is, the thick plate portion 21B is formed in a U shape extending from the outflow / inflow opening 20A side of the bottom plate 20 toward the bucket mounting plate 12D side and extending toward a bent portion 20C of the bottom plate 20 described later.

  In each thick plate portion 21B, the bucket 19 is in the closed position, and the inner end in the opening and closing direction is the opening 21B1. Each thick plate portion 21B is formed as a plate material thicker than the thin plate portion 21A, and reinforces a portion where stress is concentrated on the bucket 19 at the time of excavation. Therefore, each thick plate portion 21B is formed with a portion corresponding to the digging claw 23 described later, a portion corresponding to the bucket attachment portion 12D1 of the bucket attachment plate 12D, a portion to which the link 14 is attached, and a bent portion 20C described below. The rear end portion of the bottom plate 20 is formed.

  Each thick plate portion 21B is provided with a connecting portion 21C at a position corresponding to the bucket mounting portion 12D1 of the bucket mounting plate 12D. The connecting portion 21C is attached to the bucket attaching portion 12D1 of the bucket support member 12 by using the connecting pin 22. The connecting pin 22 serves as a pivot O for opening and closing (pivoting) the bucket 19 between the open position and the closed position. Further, in each thick plate portion 21B, a link attachment portion 21D is provided on the side opposite to the opening 21B1 (rear end side) outside the connecting portion 21C in the opening / closing direction. The link 14 is rotatably attached to the link attachment portion 21D using a connection pin 16.

  The bottom plate 20 of the bucket 19 is provided on a rear end side (the other end side) of a curved portion 20B which curves and extends in a convex shape from the in / out opening 20A and a curved portion 20B opposite to the in / out opening 20A. It consists of a bent portion 20C bent in a direction away from the rotation support point O (outside in the opening and closing direction). Side plates 21 are fixed by welding or the like on both end sides of the curved portion 20B in the width direction. A plurality of (for example, three) digging claws 23 are attached at an interval in the width direction (longitudinal direction of the cross beam portion 12B) on the outflow / inflow opening 20A side of the curved portion 20B.

  Next, the bent portion 20C of the bottom plate 20 will be described.

  As shown in FIGS. 3 and 5, the bending portion 20C is bent toward the outside in the opening and closing direction from the rear end side of the bending portion 20B when the bucket 19 is in the closed position. The bent portions 20C are fixed to the thick plate portion 21B of the side plate 21 by welding at both ends in the width direction, and extend in the width direction (between the thick plate portions 21B of the side plates 21). That is, the bending portion 20C is formed at the rear end portion of the bottom plate 20 where stress is concentrated at the time of excavation, thereby improving the strength of the rear end side of the bottom plate 20.

  As shown in FIG. 5, when the bucket 19 is in the closed position, the bending portion 20C falls within a range (bending angle α) between the extension line A-A of the bending portion 20B and the horizontal surface G1-G1. It is bent. In this case, by bending the bent portion 20C so that the bending angle α approaches the horizontal plane G1-G1, the welding length with the thick plate portion 21B can be lengthened, and the strength of the rear end side of the bottom plate 20 is obtained. Improve.

  The bending portion 20C is bent outward from the bending portion 20B in the opening and closing direction. Thereby, the strength is improved without increasing the weight of the bucket 19. Further, since the bottom plate 20 does not have corner portions that the soil (clay, mud) in the sediment storage space S1 becomes compacted, adhesion of the soil to the bottom plate 20 is reduced to improve soil removal performance. I am doing it. Further, the scraping plate 17C of the soil removing device 17 is as close as possible to the bottom plate 20 to improve the soil removing property. Furthermore, the rear end side of the bottom plate 20 of the bucket 19 becomes wider in the opening and closing direction, and it is possible to reduce that the earth and sand trapped in the earth and sand storage space S1 overflows from the bent portion 20C and spills.

  The position of the bent portion 20C of the bottom plate 20 when the bucket 19 is in the closed position is closer to the pivot fulcrum O than the position of the inflow / outflow opening 20A when the bucket 19 is in the open position. That is, as shown in FIG. 5, the rear end 20C1 of the bent portion 20C is rotated more than the position Df1 (the alternate long and short dash line B-B perpendicular to the ground G passing the Df1) of the outflow / inflow opening 20A at the open position of the bucket 19 It is located on the movement fulcrum O (connection pin 22) side. In this case, the position Df1 of the inflow / outflow opening is a boundary between the ground G and the excavated surface Df. This reduces the contact of the bending portion 20C with the excavating surface Df and the ground G at the time of excavation, so that the excavation work can be performed efficiently. In this case, the excavating surface Df is a locus of the inflow / outflow opening 20A of the bottom plate 20 while the bucket 19 rotates between the open position and the closed position.

  On the other hand, the bucket 24 also has the bottom plate 25 receiving sediment that has flowed in at the closed position (the state of FIG. 3), with the front end side (one end side) facing the sediment inflow opening 25A, like the bucket 19; It consists of a pair of side plates 26 provided at both ends in the (lateral direction) and facing each other, and a sediment storage space S2 formed inside surrounded by the bottom plate 25 and the pair of side plates 26. The side plate 26 includes a thin plate portion 26A, a thick plate portion 26B having an opening 26B1, a connecting portion 26C, and a link attaching portion 26D.

  On the other hand, the bottom plate 25 is configured to include a bending portion 25B and a bending portion 25C bent outward from the rear end of the bending portion 25B in the opening and closing direction. On the side of the inflow / outlet opening 25A of the curved portion 25B, a plurality of (for example, two) digging claws 27 are attached so as to be located between the respective digging claws 23 of the bucket 19. Further, the rear end 25C1 of the bent portion 25C is located closer to the pivot fulcrum O (connection pin 22) than the position Df1 of the outflow / inflow opening 25A at the open position of the bucket 24. The bucket 24 is attached to the bucket attachment portion 12D1 of the bucket support member 12 so as to be capable of pivoting (opening and closing) upward and downward with the coupling portion 26C using the coupling pin 16.

  The clamshell bucket 11 according to the first embodiment has the above-described configuration, and an operation of the shaft excavating machine 1 equipped with the clamshell bucket 11 excavating the shaft P will be described below.

  First, after the shaft drilling machine 1 is run to the vicinity of the shaft P, the boom 7A of the working device 7 is extended to the front side, and the multistage telescopic arm 7B is extended in the vertical direction with respect to the ground G. Then, as shown in FIG. 1, the clamshell bucket 11 is grounded to the bottom (ground G) of the shaft P by extending the multistage telescopic arm 7B while holding the buckets 19 and 24 in the open position. In this state, by turning the clamshell bucket 11 from the open position to the closed position, soil on the bottom of the shaft P can be scooped.

  After the earth and sand are scooped by the clamshell bucket 11, with the multistage telescopic arm 7B contracted by the arm telescopic cylinder, the tip of the boom 7A is lifted upward, and the multistage telescopic arm 7B is rotated at the front end of the boom 7A. Move it. Thereby, the clamshell bucket 11 can be extracted from the shaft P upward. In this state, the excavated earth and sand can be loaded on a dump truck (not shown) by pivoting the upper revolving superstructure 3 and pivoting the clamshell bucket 11 from the closed position to the open position.

  By the way, in the clamshell bucket described in the above-mentioned prior art, the reinforcing plate is fixed to the rear end side of the bottom plate to improve the strength of the bottom plate and the side plate. Here, the drilling capacity of the shaft drilling machine is determined by the total weight of the weight of the clamshell bucket and the weight of earth and sand provided by the clamshell bucket. Therefore, when the weight of the entire clamshell bucket is increased by the reinforcing plate, there is a problem that the digging capacity of the clamshell bucket is reduced. Also, for example, when soil (water, clay, etc.) containing water is pressed into the corner between the reinforcing plate and the bottom plate and the soil becomes compacted, the soil may stick to the corner and the soilability may deteriorate. There is.

  So, in this embodiment, the bending parts 20C and 25C bent toward the outer side of the opening / closing direction are provided in the rear end side of the bottom plates 20 and 25 of the buckets 19 and 24, respectively. Thereby, at the rear end portion of the bottom plates 20 and 25 where stress is concentrated at the time of excavation, the weld length between the thick plate portions 21B and 26B of the side plates 21 and 26 and the bent portions 20C and 25C is lengthened to increase weight. Without the strength. Therefore, even if the clamshell bucket 11 is reinforced, the reduction of the capacity is suppressed to improve the working efficiency.

  Also, since the bottom plates 20, 25 do not have corner portions that would consolidate the soil (clay, mud) in the sediment storage spaces S1, S2, it is possible to reduce the adhesion of the soil to the bottom plates 20, 25. Dischargeability is improved. Further, since the scraping plates 17C and 18C of the soil removing devices 17 and 18 are as close as possible to the bottom plates 20 and 25, the soil stuck to the bottom plates 20 and 25 when the buckets 19 and 24 are drained is scraped efficiently It can be dropped and improves the drainage. Furthermore, in the buckets 19 and 24, the rear end sides of the bottom plates 20 and 25 become wider in the opening and closing direction, and it is reduced that the earth and sand trapped in the earth and sand storage spaces S1 and S2 overflows from the bent portions 20C and 25C and spills .

  Thus, according to the present embodiment, the clamshell bucket 11 is provided in the working device 7 of the construction machine (shaft drilling machine 1), and the closed position approaches the open position spaced apart from each other about the respective pivot point O And a pair of buckets 19 and 24 which can be opened and closed between the front and rear sides of the pair of buckets 19 and 24 and the bottom plate 20 receiving the sediment which has flowed into the interior at the closed position. , 25 and a pair of side plates 21 and 26 provided at both ends in the width direction of the bottom plates 20 and 25 and facing each other, the inside surrounded by the bottom plates 20 and 25 and the pair of side plates 21 and 26 It consists of sediment storage space S1 and S2 which were formed.

  The bottom plates 20 and 25 of the buckets 19 and 24 are located on the opposite side of the curved portions 20B and 25B which are curved and extended in a convex shape from the inflow and outflow openings 20A and 25A and the inflow and outflow openings 20A and 25A. The bending portions 20C and 25C are provided on the rear end side of the bending portions 20B and 25B and are bent in the direction away from the pivot O. Thereby, sufficient strength can be secured while suppressing the earth removal property and the increase in weight of the clamshell bucket 11.

  The positions of the bent portions 20C and 25C of the bottom plates 20 and 25 when the pair of buckets 19 and 24 are in the closed position are the outflows when the pair of buckets 19 and 24 are in the open position. The rotation fulcrum O side is on the side of the positions of the entrances 20A and 25A. As a result, contact of the bending portions 20C and 25C with the excavating surface Df and the ground G is reduced at the time of excavation, so that the excavation work can be performed efficiently.

  Next, FIG. 6 shows a second embodiment of the present invention. A feature of the present embodiment is that the bent portion of the bottom plate is formed to have a thickness greater than the thickness of the curved portion. In the second embodiment, the same components as those in the first embodiment described above are denoted by the same reference numerals, and the description thereof will be omitted. Further, in FIG. 6, only one bucket 31 is shown, and the shape and configuration of the other bucket are the same, so only the bucket 31 will be described and the description of the other bucket will be omitted.

  The bucket 31 includes a bottom plate 32 for receiving earth and sand, and a pair of side plates 33 provided on both ends in the width direction of the bottom plate 32 and facing each other. The bottom plate 32 is configured to include a bending portion 32A and a bending portion 32B provided on the rear end side of the bending portion 32A. The bending portion 32B is separate from the bending portion 32A, and is bent outward in the opening and closing direction. The bent portion 32B of the bottom plate 32 is formed to have a thickness t2 thicker than the thickness t1 of the curved portion 32A, and is fixed to the rear end side of the curved portion 32A by welding or the like. Thereby, the strength on the rear end side of the bottom plate 32 where stress is concentrated at the time of excavation is further improved.

  Thus, also in the second embodiment configured as described above, the same actions and effects as those of the first embodiment can be obtained. In particular, in the second embodiment, since the plate thickness t2 of the bent portion 32B is formed to be larger than the plate thickness t1 of the curved portion 32A, the increase in weight of the bucket 31 is suppressed and the strength is further improved. There is.

  In addition, in 1st Embodiment mentioned above, the case where the clamshell bucket 11 was attached to the telescopic type shaft drilling machine 1 was mentioned as the example, and was demonstrated. However, the present invention is not limited to this, and for example, the clamshell bucket 11 may be suspended and used as a wire of a crane, or the clamshell bucket 11 may be used instead of the broom bucket of a hydraulic shovel. The same applies to the second embodiment.

  Moreover, in the embodiment mentioned above, the shaft excavation machine 1 provided with the crawler type lower traveling body 2 was mentioned as an example, and was explained. However, the present invention is not limited to this, and may be applied to a shaft excavator equipped with a wheel type undercarriage.

1 Vertical shaft drilling machine (Construction machine)
7 Work apparatus 11 Clamshell bucket 19, 24, 31 Bucket 20, 25, 32 Bottom plate 20A, 25A Inflow and outflow opening 20B, 25B, 32A Curved portion 20C, 25C, 32B Curved portion 21, 26, 33 Side plate S1, S2 Sediment reservoir Space O Rotating fulcrum t1 Thickness of curved portion Thickness t2 of curved portion

Claims (3)

It has a pair of buckets provided in the working device of the construction machine, which can be opened and closed between an open position spaced apart from each other about the respective pivot point and a closed position approached,
The bottom plate of the pair of buckets has a bottom plate for receiving sediment that flows in and out at the closed position;
A pair of side plates provided respectively at both ends in the width direction of the bottom plate and facing each other;
A clamshell bucket comprising a sediment storage space formed in the interior surrounded by the bottom plate and the pair of side plates,
The bottom plate of the bucket is provided at a rear end side of the curved portion located on the opposite side to the curved portion extending in a convex shape from the outflow and inflow opening and away from the pivot point A clamshell bucket characterized by comprising a bent portion which is bent in the opposite direction.   The position of the bent portion of the bottom plate when the pair of buckets is in the closed position is closer to the pivot point than the position of the inflow / outlet opening when the pair of buckets is in the open position A clamshell bucket according to claim 1, characterized in that   The clamshell bucket according to claim 1, wherein the bent portion of the bottom plate is formed thicker than the thickness of the curved portion and is fixed to a rear end side of the curved portion.

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