AU2014100261A4 - A hydraulically controlled flat grab bucket - Google Patents

Abstract

A HYDRAULICALLY CONTROLLED FLAT GRAB BUCKET Abstract The present invention relates to a hydraulically controlled flat grab bucket including an upper bearing beam, lower bearing beam and a bucket body. The upper and lower bearing beams are connected through a bucket opening hydraulic cylinder. The bucket body is hingedly connected with the lower bearing beam. The upper bearing beam includes at least one strut guide unit, which includes a strut control hydraulic cylinder and a strut. One end of the strut is hingedly connected with the bucket body. The other end of the strut is connected with the strut control hydraulic cylinder. The hydraulically controlled flat grab bucket further includes a hydraulic control device which controls the function of a bucket opening hydraulic cylinder and the strut control hydraulic cylinder. The advantages of the present invention include: 1) Simple construction and easy operability; 2) Smoother, more level dredging of riverbeds or seabeds to meet more stringent development requirements; and 3) Increased maximum bucket grab width and digging depth and easy variation to meet the needs of different jobs and applications. ----- k--- - Fig r 1~~~. -- ----t -------- ...~ ...... Figure 1

Description

- 1 A HYDRAULICALLY CONTROLLED FLAT GRAB BUCKET Technical field [0001] The present invention relates to a hydraulically controlled flat grab bucket and in particular to a hydraulically controlled flat grab bucket for underwater dredging projects. Technical background [0002] Grab buckets are excavation equipment and have a primary application in dredging. In the present day, grab bucket type dredgers are widely used for dredging seabeds and riverbeds for developing and maintaining large shipping ports. In these dredgers, the grab bucket is the primary dredging component. The major subcomponents of the grab bucket include an upper bearing beam, lower bearing beam, strut, bucket body, steel wire rope and a pulley. [0003] A dredging operation using a grab bucket generally leaves the seabed or riverbed in an uneven state, due primarily to the bucket shape and limited grab motion. However, many modern engineering applications require a highly level seabed or riverbed and dredging operations using conventional grab buckets often do not meet these strict requirements. Therefore, there is a desire for a new type of grab bucket to provide more levelling dredging to meet the requirements of modern development projects. [0004] Any discussion of the prior art throughout the specification should in no way be considered as an admission that such prior art is widely known or forms part of common general knowledge in the field. Summary of the invention [0005] It is an object of preferred embodiments of the present invention to provide a hydraulically controlled flat grab bucket for dredging a seabed or riverbed with a high degree of flatness. [0006] It is an object of the present invention to overcome or ameliorate at least one of the disadvantages of the prior art, or to provide a useful alternative. [0007] According to a first embodiment of the present invention, there is provided a hydraulically controlled flat grab bucket including: an upper bearing beam, a lower bearing beam, -2 a bucket body, and a hydraulic control device; wherein the upper bearing beam is connected with the lower bearing beam by a bucket opening hydraulic cylinder, the bucket body is hingedly connected with the lower bearing beam, a strut bearing unit is mounted to the upper bearing beam, the strut bearing unit includes a strut control hydraulic cylinder and at least one strut, a first end of the at least one strut is hingedly connected to the bucket body, a second end of the at least one strut is connected with the strut control hydraulic cylinder; and wherein the hydraulic control device controls both the bucket opening hydraulic cylinder and the strut control hydraulic cylinder. [0008] In one embodiment, the hydraulic control device includes: a hydraulic pump; a bucket opening directional control valve; a strut directional control valve; a bucket opening unidirectional balancing valve; a strut unidirectional balancing valve; a unidirectional valve; a relief valve; and a driving motor disposed on the upper bearing beam; wherein said bucket opening hydraulic cylinder includes a rodless cylinder chamber, which connects with the bucket opening directional control valve, the bucket opening hydraulic cylinder includes a rod cylinder chamber, which connects with the bucket opening unidirectional balancing valve, the bucket opening unidirectional balancing valve in turn connects with the bucket opening directional control valve, said strut control hydraulic cylinder includes a rodless cylinder chamber, which connects with said strut directional control valve, said strut control hydraulic cylinder includes a rod cylinder chamber, which connects with said strut unidirectional balancing valve, said strut unidirectional balancing valve in turn connects with said strut directional control valve, said bucket opening directional control valve and said strut directional control valve connect with said unidirectional valve and said hydraulic pump respectively, said strut -3 directional control valve is connected with said hydraulic pump through said relief valve, and said driving motor connects with said hydraulic pump. [0009] In one embodiment, two strut guide units are respectively mounted to two ends of the upper bearing beam. [0010] In one embodiment, one strut guide unit includes two struts, a first end of a first strut is hingedly connected to a first end of the bucket body and a first end of a second strut is hingedly connected to a second end of the bucket body; second ends of the first and second struts are connected to strut control hydraulic cylinder through a connection rod. [0011] In one embodiment, a lower part of the bucket body defines a cutting edge. [0012] In one embodiment, the upper bearing beam includes two cylinder guides, each said cylinder guide being disposed at a respective opposing end of the upper bearing beam and being adapted to support the movement of the corresponding strut. [0013] In one embodiment, the bucket opening hydraulic cylinder and the strut control hydraulic cylinder are formed from a high strength steel alloy. [0014] The present invention employs the strut control hydraulic cylinders to vertically push the corresponding struts so as to facilitate a substantially horizontal mutual engagement of the left and right portions of the bucket body during the bucket closing. This engagement process performs the digging using the cutting edge of the bucket. In addition, movement of the strut control hydraulic cylinder is able to vary the maximum opening width and digging depth of the bucket to meet various operation demands. [0015] The advantages of the present invention are: 1. Simple construction and easy operability; 2. It can dig smoother levels of riverbeds or seabeds so as to meet smoothness requirements; 3. The maximum bucket grab width and digging depth can be easily varied to meet the needs of different jobs and applications; and 4. Due to employment of the proportional directional switching valve and the unidirectional balancing valve, the precise control of the bucket opening hydraulic cylinder and the strut control hydraulic cylinder can be ensured so as to keep the accuracy of the operation. Description of the drawings [0016] Preferred embodiments of the present invention will now be described with reference to the accompanying drawings, in which: Figure 1 shows the main structure of a hydraulically controlled flat grab bucket; Figure 2 is a left side view of the grab bucket of Figure 1; -4 Figure 3 is a hydraulic circuit illustrating the hydraulic control device of the grab bucket of Figure 1; and Figure 4 is a geometrical illustration of exemplary dimensions of a hydraulically controlled flat grab bucket according to an embodiment of the invention. [0017] In the drawings, the following numbers indicate the corresponding features: 1 - upper bearing beam; 2 - strut; 3 - bucket body; 4 - lower bearing beam; 5 - bucket opening hydraulic cylinder; 6 - cylinder guide; 7 - strut control hydraulic cylinder; 8 - driving motor; 9 - cutting edge; 10 - relief valve; 11 - unidirectional valve; 12 - bucket opening directional control valve; 13 - strut unidirectional balancing valve; 14 - hydraulic pump; 15 - connection rod; 16 strut directional control valve; 17 - bucket opening unidirectional balancing valve. Embodiments of the invention [0018] Referring initially to Figures 1 to 3, there is illustrated a hydraulically controlled flat grab bucket. The grab bucket includes an upper bearing beam 1 and a lower bearing beam 4 connected to the upper bearing beam by a bucket opening hydraulic cylinder 5. A bucket body 3 is hingedly connected with the lower bearing beam 4. A hydraulic control device controls the bucket opening hydraulic cylinder 5. [0019] Two strut guide units are respectively mounted to two ends of upper bearing beam 1, as shown in Figure 1. Each strut guide unit includes a strut control hydraulic cylinder 7 and a respective strut 2. First ends of struts 2 hingedly connect with respective opposing sides of bucket body 3. Second ends of each strut 2 hingedly connect with respective strut control hydraulic cylinders 7 through connection rod 15, as shown in Figure 2. Strut control hydraulic cylinders 7 and bucket opening hydraulic cylinder 5 are formed of high strength steel alloy. [0020] Referring to Figure 3, the hydraulic control device includes a hydraulic pump 14, a bucket opening directional control valve 12, a strut directional control valve 16, a bucket opening unidirectional balancing valve 17, a strut unidirectional balancing valve 13, a unidirectional valve 11, a relief valve 10 and a driving motor 8. The driving motor 8 is located on upper bearing beam 1. [0021] The bucket opening hydraulic cylinder 5 includes a rodless cylinder chamber, which connects with the bucket opening directional control valve 12. The bucket opening hydraulic cylinder 5 includes a rod cylinder chamber, which connects with bucket opening unidirectional balancing valve 17. Balancing valve 17 in turn connects with bucket opening directional control valve 12.

-5 [0022] The strut control hydraulic cylinder 7 includes a rodless cylinder chamber, which connects with strut directional control valve 16. The strut control hydraulic cylinder 7 also includes a rod cylinder chamber, which connects with strut unidirectional balancing valve 13. Balancing valve 13 in turn connects with strut directional control valve 16. The bucket opening directional control valve 12 and strut directional control valve 16 connect with unidirectional valve 11 and hydraulic pump 14 respectively. The strut directional control valve 16 is connected with hydraulic pump 14 through relief valve 10. The driving motor 8 is connected with the hydraulic pump 14. [0023] In the present embodiment, a lower part of said bucket body 3 defines a cutting edge for cutting into earth, mud or soil in a dredging operation. Disposed within two opposing ends of upper bearing beam 1, are respective cylinder guides 6. Guides 6 act to support the movement of strut 2. [0024] In the illustrated embodiment, struts 2, bucket body 3, cylinder guide 6 and strut control hydraulic cylinder 7 are all symmetrically disposed in reciprocal pairs. [0025] Each of the valves, including relief valve 10, unidirectional valve 11, bucket opening unidirectional balancing valve 12, strut directional control valve 16, bucket opening unidirectional balancing valve 17, strut unidirectional balancing valve 13, and hydraulic pump 14 are all sufficiently sealed to prevent interior exposure to water and sand during underwater dredging operations. [0026] The bucket opening hydraulic cylinder 5 and strut control hydraulic cylinder 7 are both formed from a high strength steel alloy being highly hermetic to prevent interior exposure to water and sand during underwater operation. [0027] To make proper use of cutting edge 9 of bucket body 3, during a digging or dredging process the bucket opening hydraulic cylinder 5 is controlled in conjunction with both the strut control hydraulic cylinders 7. Cylinders 7 are controlled by the hydraulic control device and operate simultaneously to linearly extend or retract respective struts 2. The hydraulic control device controls the operation of the bucket opening hydraulic cylinder 6 and the strut control hydraulic cylinders 7. Bucket opening directional control valve 12 and strut directional control valve 16 act to simultaneously control the movement of strut control hydraulic cylinders 7 during the movement of open/close oil cylinder 5. The mechanical relationship between these cylinders and valves can be described mathematically and represented as a mathematic function.

-6 [0028] As shown in Figure 4, a hydraulically controlled flat grab bucket with volume of 3 m 3 is illustrated geometrically. Here, '0' is a geometric origin indicative of the centre position of the upper bearing beam 1. Li represents the distance from an upper hinge point of strut 2 to the origin '0'. L2 indicates a length of strut 2. The dimensions of bucket body 3 are respectively L3, L4 and L5. L6 represents the maximum opening width of the bucket. In an exemplary case, the actual size of the bucket is given by the following measures: Li =500 mm, L2=2713 mm, L3=1 726 mm, L4=2225 mm, L5=1932 mm and L6=4141 mm. Using a known mathematical model, the following functional relationship between y 1 , which represents strut control hydraulic cylinder 7, and y 2 ,, which represents the open/close oil cylinder 5, can be determined as follows: yi= (-9.348x10 3 ") Y2 5 - (1.388x10 8 ) Y2 4 - (8.209x10 5 ) Y2 3 - 0.2422 Y2 2- 3 56

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8 Y2 - 2.104x10 5 [0029] The substantially horizontal dredging motion can be achieved through adjusting the bucket opening directional control valve 12 and strut directional control valve 16 so as to control the movements of strut control hydraulic cylinder 7 and bucket opening hydraulic cylinder 5. [0030] The principle of operation of the present invention is that when driving motor 8 is in action, hydraulic pump 14 is actuated. This driving the high pressure oil to enter bucket opening hydraulic cylinder 5 and strut control hydraulic cylinder 7 through unidirectional valve 11, bucket opening directional control valve 12 and strut directional control valve 16. This process causes the bucket opening hydraulic cylinder 5 to close and also cause the strut control hydraulic cylinder 7 to move up and down. [0031] During a digging or dredging operation using the grab bucket, the bucket opening hydraulic cylinder 5 supports lower bearing beam 4 and effects the general opening and closing of bucket body 3. Simultaneously, strut control hydraulic cylinders 7 move complementarily under control by valve 12 and valve 16. The movement of strut 2 up and down along cylinder guide 6 compensates for the height difference of cutting edge 9 of bucket body 3 during opening and closing. Accordingly, cutting edge 9 moves substantially horizontally during an opening or closing motion of the bucket so as to meet a desired digging precision. [0032] Through use of strut control hydraulic cylinders 7 in the present invention, the pushing motion of struts 2 during the closing process tightly controls the motion of the left and right portions of bucket body 3. This complementary motion with the motion of hydraulic cylinder 5 compensates for any height differences of cutting edge 9 during the digging motion so that the cutting edge opens and closes substantially horizontally. Further, control of strut control hydraulic cylinder 7 enhances the available opening width and digging depth of the bucket to thereby meet tougher operating requirements. The present invention can be used not -7 only for conventional dredging operations but also for high precision dredging operations having stringent seabed or riverbed flatness requirements. [0033] Key features of the present invention include the following. [0034] Struts 2 move up and down along cylinder guides 6 through the controlled pushing motion of strut control hydraulic cylinders 7. In conjunction with the motion achieved by hydraulic cylinder 5, the relative motion of struts 2 maintain a level cutting edge 9 to achieve a primarily horizontal digging motion. Therefore, the protection scope will not be limited to the abovementioned embodiment. [0035] Thus, while there has been described what are believed to be the preferred embodiments of the invention, those skilled in the art will recognise that other and further modifications may be made thereto without departing from the spirit of the invention, and it is intended to claim all such changes and modifications as falling within the scope of the invention. For example, in various other embodiments strut control hydraulic cylinder 7 and cylinder guide 6 are located in the middle of upper bearing beam 1, and the left and right portions of the bucket body 3 and lower bearing beam 4 have two symmetrical hinge points etc.

Claims (7)

1. A hydraulically controlled flat grab bucket including: an upper bearing beam, a lower bearing beam, a bucket body, and a hydraulic control device; wherein the upper bearing beam is connected with the lower bearing beam by a bucket opening hydraulic cylinder, the bucket body is hingedly connected with the lower bearing beam, a strut bearing unit is mounted to the upper bearing beam, the strut bearing unit includes a strut control hydraulic cylinder and at least one strut, a first end of the at least one strut is hingedly connected to the bucket body, a second end of the at least one strut is connected with the strut control hydraulic cylinder; and wherein the hydraulic control device controls both the bucket opening hydraulic cylinder and the strut control hydraulic cylinder.

2. A hydraulically controlled flat grab bucket according to claim 1 wherein the hydraulic control device includes: a hydraulic pump; a bucket opening directional control valve; a strut directional control valve; a bucket opening unidirectional balancing valve; a strut unidirectional balancing valve; a unidirectional valve; a relief valve; and a driving motor disposed on the upper bearing beam; wherein said bucket opening hydraulic cylinder includes a rodless cylinder chamber, which connects with the bucket opening directional control valve, the bucket opening hydraulic cylinder includes a rod cylinder chamber, which connects with the bucket opening unidirectional balancing valve, the bucket opening unidirectional balancing valve in turn connects with the bucket opening directional control valve, said strut control hydraulic cylinder includes a rodless cylinder chamber, which connects with said -9 strut directional control valve, said strut control hydraulic cylinder includes a rod cylinder chamber, which connects with said strut unidirectional balancing valve, said strut unidirectional balancing valve in turn connects with said strut directional control valve, said bucket opening directional control valve and said strut directional control valve connect with said unidirectional valve and said hydraulic pump respectively, said strut directional control valve is connected with said hydraulic pump through said relief valve, and said driving motor connects with said hydraulic pump.

3. A hydraulically controlled flat grab bucket according to claim 1 or claim 2 including two strut guide units respectively mounted to two ends of the upper bearing beam.

4. A hydraulically controlled flat grab bucket according to claim 3 wherein each said strut guide unit includes two struts, a first end of each said strut hingedly connects with a respective side of the bucket body, and a second end of each said strut connects with the strut control hydraulic cylinder through a connection rod.

5. A hydraulically controlled flat grab bucket according to claim 1 wherein a lower part of the bucket body defines a cutting edge.

6. A hydraulically controlled flat grab bucket according to claim 1 wherein the upper bearing beam includes two cylinder guides, each said cylinder guide being disposed at a respective opposing end of the upper bearing beam and being adapted to support the movement of the corresponding strut.

7. A hydraulically controlled flat grab bucket according to claim 1 wherein said bucket opening hydraulic cylinder and said strut control hydraulic cylinder are formed from a high strength steel alloy.