EP1211356A1 - Grab bucket - Google Patents
Grab bucket Download PDFInfo
- Publication number
- EP1211356A1 EP1211356A1 EP01309894A EP01309894A EP1211356A1 EP 1211356 A1 EP1211356 A1 EP 1211356A1 EP 01309894 A EP01309894 A EP 01309894A EP 01309894 A EP01309894 A EP 01309894A EP 1211356 A1 EP1211356 A1 EP 1211356A1
- Authority
- EP
- European Patent Office
- Prior art keywords
- grab
- hydraulic cylinder
- frame
- shells
- grab bucket
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Withdrawn
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Classifications
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B66—HOISTING; LIFTING; HAULING
- B66C—CRANES; LOAD-ENGAGING ELEMENTS OR DEVICES FOR CRANES, CAPSTANS, WINCHES, OR TACKLES
- B66C3/00—Load-engaging elements or devices attached to lifting or lowering gear of cranes or adapted for connection therewith and intended primarily for transmitting lifting forces to loose materials; Grabs
- B66C3/06—Grabs actuated by a single rope or chain
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B66—HOISTING; LIFTING; HAULING
- B66C—CRANES; LOAD-ENGAGING ELEMENTS OR DEVICES FOR CRANES, CAPSTANS, WINCHES, OR TACKLES
- B66C3/00—Load-engaging elements or devices attached to lifting or lowering gear of cranes or adapted for connection therewith and intended primarily for transmitting lifting forces to loose materials; Grabs
- B66C3/14—Grabs opened or closed by driving motors thereon
- B66C3/16—Grabs opened or closed by driving motors thereon by fluid motors
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- E—FIXED CONSTRUCTIONS
- E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
- E02F—DREDGING; SOIL-SHIFTING
- E02F3/00—Dredgers; Soil-shifting machines
- E02F3/04—Dredgers; Soil-shifting machines mechanically-driven
- E02F3/46—Dredgers; Soil-shifting machines mechanically-driven with reciprocating digging or scraping elements moved by cables or hoisting ropes ; Drives or control devices therefor
- E02F3/47—Dredgers; Soil-shifting machines mechanically-driven with reciprocating digging or scraping elements moved by cables or hoisting ropes ; Drives or control devices therefor with grab buckets
Definitions
- This invention relates to a grab bucket for use in cargo work for handling bulk cargo of various materials, which is suspended from a crane or the like.
- a single-rope grab bucket operated by a crane or the like has been conventionally used for hauling bulk cargo such as a pile of wood chips, crushed ore, earth, sand, wastes, scrap, rubbish and other fragmentary materials.
- the illustrated grab bucket comprising a grab 1 formed of a pair of shells 2 hinged facing each other, a lower frame 3 having axes 2a for rotatably supporting the shells 2, an upper frame 5 placed over the lower frame 3 and connected with the lower frame 3 through the rear walls of the shells 2 and suspension arms 4, an intermediate movable frame 7 placed between the upper frame 5 and lower frame 3 and connected with the lower frame 3 through a hydraulic cylinder 6, a wire rope 8 run around sheaves which are mounted respectively on the intermediate movable frame 7 and upper frame 5 and elongate upward to lift and close the grab, and a hydraulic cylinder control means for controlling the operation of the hydraulic cylinder 6 by opening or dosing an oil passage in the hydraulic cylinder 6.
- the hydraulic cylinder control means When opening the grab 1, the hydraulic cylinder control means is operated to set the hydraulic cylinder 6 free, so that the lower frame 3 is separated from the intermediate movable frame 7 and lowered by the weight of the lower frame including the shells. Consequently, the rotating axes 2a are brought down while suspending the rear walls of the shells 2 by the suspension arms 4, thereby to open the grab.
- the closing operation of the grab 1 in the open state is effected by letting out the wire rope 8 in the descending direction while keeping the hydraulic cylinder 6 in its free state, to lowering the intermediate movable frame 7 to be placed close to the lower frame 3, tugging the wire rope 8 while keeping the hydraulic cylinder 6 in its inextensible state to pull up the intermediate movable frame 7 toward the upper frame 5, thus to cause both the shells 2 to be mutually closed.
- the conventional grab bucket entailed a disadvantage such that the subsequent grabbing work cannot but seize hold of the adhesional materials while allowing the adhesional materials adhered to the grab, consequently to decreasing the working efficiency.
- This invention is made to eliminate the drawbacks suffered by the conventional grab bucket as described above and seeks to provide a grab bucket capable of successfully releasing materials grabbed even if the materials held inside are easily adhesive to the inside of the grab bucket.
- a grab bucket comprising a pair of shells opposed to each other in their openable state for constituting a grab, a lower frame for pivotably supporting the shells, an upper frame placed above the lower frame and connected with the backs of the shells through suspending arms, an intermediate movable frame placed between the upper and lower frames and connected with the lower frame through a hydraulic cylinder, a wire rope for suspending and dosing the grab, which wire pope has the lower end fixed onto the intermediate movable frame and runs through sheaves mounted on the intermediate movable frame and the upper frame, and a by-pass passage for connecting the upper end portion of the hydraulic cylinder with the cylinder body of the hydraulic cylinder to accelerate a piston movable between the upper end portion and the cylinder body of the hydraulic cylinder.
- the shells may preferably be formed so that their inner bottoms are inclined up inwardly when opening the grab.
- the shells may preferably have the inside made of stainless steel.
- reference numeral 1 denotes a grab, 3 a lower frame, 4 suspending arms, 5 an upper frame, 6 a hydraulic cylinder, 7 an intermediate movable frame, and 8 a wire rope.
- the grab bucket of this invention comprises a pair of shells 2 opposed to each other in their openable state for constituting the grab 1, the lower frame 3 for pivotably supporting the shells 2, which is rotatable around axial shafts 3a, the upper frame 6 placed above the lower frame 3 and connected with the backs of the shells 2 through suspending arms 4, the intermediate movable frame 7 placed between the upper and lower frames and connected with the lower frame 3 through the hydraulic cylinder 6, the wire rope 8 for suspending and closing the grab, which has the lower end fixed onto the intermediate movable frame 7 and runs through sheaves mounted on the intermediate movable frame 7 and the upper frame 5, and a control means for controlling the hydraulic cylinder 6 by opening or closing an oil passage leading to the interior of the hydraulic cylinder 6.
- the grab 1 is constituted by the shells 2 supported on the lower frame 3 rotatably around the axial shafts 3a.
- a grabbing space 9 for seizing hold of a pile of wood chips, crushed ore, earth, sand, wastes, scrap, rubbish and other fragmentary materials is formed therebetween.
- Each shell 2 has an inner surface made of stainless steel and an inner bottom 10 which assumes its posture inclined slightly inward and perpendicularly to the surface of the earth when the grab is opened fully.
- the lower end of the suspending arm 4 is rotatably joined to the back of each shell 2, and the upper end of the suspending arm 4 is rotatably joined to the upper frame 5, so that the shells 2 are suspended from the upper frame 5.
- reference numeral 13 denotes an oil port formed in the upper portion of the oil tank 11, and reference numeral 14 denotes a receiving antenna for the radio-signal receiver 12.
- the radio-signal receiver 12 issues a command to open an oil hydraulic circuit for controlling the hydraulic cylinder 6 upon reception of a signal from the radio-signal receiver.
- the intermediate movable frame 7 is formed so as to define a hollow space 15 thereinside. On its front lower right side and rear lower left side of the intermediate movable frame 7, there are fixed sheave cases 16 containing rotatable sheaves 17.
- the hydraulic cylinder 6 is provided with a cylinder body 6a, a piston 6b reciprocatively contained within the cylinder body 6a, and a piston rod 6c connected with the piston 6b and retractably protruding upward from the cylinder body 6a.
- the lower end of the cylinder body 6a is joined to the lower frame 3, and the leading end of the piston rod 6b is joined to the top portion of the intermediate movable frame 7 by using a bolt or other fixing means, so that the lower dame 3 is connected with the intermediate movable frame 7 through the hydraulic cylinder 6.
- the piston 6b has passages 18 passing from the upper side through to the lower side thereof. Within each passage 18, a check valve 19 is disposed for regulating the flow of the oil passing from the upper side to the lower side of the piston 6b.
- the piston rod 6c elongates upward from the piston 6b.
- the oil hydraulic circuit for controlling the operation of the hydraulic cylinder 6 includes a conduit pipe, which is connected at its one end with the upper part of the cylinder body 6a of the hydraulic cylinder 6 and at the other end thereof with the lower part of the cylinder body through a throttle valve 21 and a pilot check valve 22. With the lower part of the cylinder body 6a, there is connected a connecting pipe 23 leading to the oil tank 11.
- the throttle valve 21 is interposed between the upper part of the cylinder body 6a and the pilot check valve 22, so as to regulate the flow of the oil flowing from the upper part to the lower part of the cylinder body 6a.
- the pilot check valve 22 is opened and closed by means of an electromagnetic valve 24.
- the pilot check valve 22 When the pilot check valve 22 is dosed, the oil within the upper chamber defined above the piston 6b in the piston body 6a is prevented from flowing to restrain the hydraulic cylinder 6 from moving downward.
- the pilot check valve 22 When the pilot check valve 22 is open, the oil is allowed to flow into the lower chamber defined below the piston 6b in the hydraulic cylinder 6 through the conduit pipe 20, thus to bring the hydraulic cylinder 6 into its free state.
- the hydraulic cylinder 6 is further provided with a by-pass passage 25 for accelerating the piston 6b.
- the by-pass passage 25 connects the upper portion of the cylinder body 6a with a portion apart from the upper portion at a prescribed distance through a by-pass conduit pipe 26.
- the by-pass conduit pipe 26 includes a throttle valve 27 for regulating the flow of the oil passing therethrough.
- the upper frame 5 is formed so as to allow the intermediate movable frame 7 to enter into the central portion thereof.
- the upper frame 5 is further provided on its front and rear sides with rotating sheaves 28.
- the intermediate movable frame 7 is suspended from the upper frame 5 and vertically movable by operating the wire rope 8. That is, as shown in FIG. 4, the wire rope 8 has the lower ends connected with both sides of the intermediate movable frame 7 and run through the sheaves 28 on the upper frame 5 and the sheaves 17, and the upward elongated part of the wire rope is caught on a hook 29.
- the grab 1 assumes its closed state in which the upper and lower frames and intermediate movable frame are close to one another and is suspended from a crane or the like.
- the pilot check valve 22 of the oil hydraulic circuit is closed to prevent the oil in the hydraulic cylinder 6 from flowing, thus to bring the hydraulic cylinder 6 to a deadlock.
- a grab-opening command is first transmitted to the radio-signal receiver 12 to apply an operating current to an electromagnetic valve (solenoid valve) 24.
- the electromagnetic valve 24 is actuated to form a passage to the pilot check valve while the operating current flows.
- the pilot check valve 22 opens to allow the oil to flow the upper chamber to the lower chamber in the cylinder body 6a through the conduit pipe 20, thus to bring the hydraulic cylinder into its free state.
- the lower frame 3 is separated from the intermediate movable frame 7 and moves downward by its own weight, thus to lower the position of the axial shaft 3a while the rear of each shell 2 is suspended from the suspending arm 4, as the result of which the grab 1 is opened.
- the hydraulic cylinder 6 is expanded to move the piston 6b upward in the cylinder body 6a.
- the by-pass conduit pipe 26 i.e. the position depicted by the chain line in FIG. 5
- the by-pass passage 25 is opened to permit the oil to flow from the upper chamber to the lower chamber in the cylinder body. Consequently, the amount of the oil flowing into the lower chamber of the cylinder body is increased to speed up the expansion of the hydraulic cylinder 6.
- the opening speed of the grab is accelerated from the open state indicated by the imaginary line (alternate long and short dash line) until the full-open state indicated by the solid line in FIG. 3.
- the expansion rate of the hydraulic cylinder 6 is increased to accelerate the opening speed of the grab, even the grabbed fragmentary materials sticking to the inner surfaces of the shells can be efficiently thrown off by the action of inertia.
- the acceleration of the opening speed can be controlled by regulating the throttle valve 27.
- the grab 1 is landed on an object to be grabbed as it is kept in its open state. Thereafter, the grab 1 in the open state is closed in such a manner that the wire rope 8 is let out downward while keeping the hydraulic cylinder 6 in the free state, thereby to lower the intermediate movable frame 7 toward the lower frame 3, and then, the wire rope 8 is pulled up to permit the lower frame 7 to approach the upper frame 5 while keeping the hydraulic cylinder 6 in its inextensible state. As a result, the axial shafts 3a are moved upward to close the shells 2.
- the pilot check valve 22 is closed to prevent the oil in the upper chamber in the cylinder body 6a from flowing into the lower chamber, thus to restrain the hydraulic cylinder from expanding.
- the oil in the lower chamber in the cylinder body flows into the upper chamber of the cylinder body through the oil passage 18 formed in the piston 6b. Consequently, the hydraulic cylinder 6 is shortened, holding its cushion effect.
- the throttle valve 27 in the by-pass passage 25 is controlled taking stickiness of the objective materials to be grabbed by the grab.
- the hydraulic cylinder 6 may be used as usual in such a manner that the throttle valve 27 is closed to dose the by-pass passage 25.
- a wireless control system for controlling the electromagnetic valve is used, but a wired control system may be substituted in place of the wireless system.
- the grab bucket comprises the grab formed of the paired shells opposed to each other in their openable state, the lower frame for pivotably supporting the shells, the upper frame placed above the lower frame and connected with the shells through the suspending arms, the intermediate movable frame placed between the upper and lower frames and connected with the lower frame through the hydraulic cylinder, the wire rope for suspending and closing the grab, and the by-pass passage for connecting the upper end portion of the hydraulic cylinder with the cylinder body of the hydraulic cylinder to accelerate the piston movable between the upper end portion and the cylinder body of the hydraulic cylinder.
- the wire pope has the lower end fixed onto the intermediate movable frame and runs through sheaves mounted on the intermediate movable frame and the upper frame.
- the opening speed of the grab can be varied, so that the scrap or other objective materials grabbed by the grab bucket of the invention can be efficiently thrown off by vibration and the action of inertia of the objective materials only by fully opening the grab.
- the grab bucket of the invention the work of grabbing a pile of wood chips, crushed ore, earth, sand, wastes, scrap, rubbish, and any other materials can effectively operated
- the grab bucket according to the invention is provided with the control valve for regulating the flow of oil in the by-pass passage, the opening speed of the grab can readily be controlled so as to throw off materials grabbed by the grab bucket, while controlling the impact caused when opening the grab with holding the cushion effect of the hydraulic cylinder.
- the control valve may be dosed to restrain a shock from occurring when releasing the grabbed materials.
- the materials grabbed by the grab of the invention can easily be thrown off when opening the grab.
- the materials grabbed by the grab can more easily be thrown off
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- Mechanical Engineering (AREA)
- Mining & Mineral Resources (AREA)
- Civil Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Structural Engineering (AREA)
- Load-Engaging Elements For Cranes (AREA)
Abstract
Description
- This invention relates to a grab bucket for use in cargo work for handling bulk cargo of various materials, which is suspended from a crane or the like.
- In general, a single-rope grab bucket operated by a crane or the like has been conventionally used for hauling bulk cargo such as a pile of wood chips, crushed ore, earth, sand, wastes, scrap, rubbish and other fragmentary materials.
- There has been known the conventional single-rope grab bucket of this type having the structure shown in FIG. 7 and FIG. 8 by way of example. The illustrated grab bucket comprising a
grab 1 formed of a pair ofshells 2 hinged facing each other, alower frame 3 havingaxes 2a for rotatably supporting theshells 2, anupper frame 5 placed over thelower frame 3 and connected with thelower frame 3 through the rear walls of theshells 2 andsuspension arms 4, an intermediatemovable frame 7 placed between theupper frame 5 andlower frame 3 and connected with thelower frame 3 through ahydraulic cylinder 6, awire rope 8 run around sheaves which are mounted respectively on the intermediatemovable frame 7 andupper frame 5 and elongate upward to lift and close the grab, and a hydraulic cylinder control means for controlling the operation of thehydraulic cylinder 6 by opening or dosing an oil passage in thehydraulic cylinder 6. - When opening the
grab 1, the hydraulic cylinder control means is operated to set thehydraulic cylinder 6 free, so that thelower frame 3 is separated from the intermediatemovable frame 7 and lowered by the weight of the lower frame including the shells. Consequently, the rotatingaxes 2a are brought down while suspending the rear walls of theshells 2 by thesuspension arms 4, thereby to open the grab. - The closing operation of the
grab 1 in the open state is effected by letting out thewire rope 8 in the descending direction while keeping thehydraulic cylinder 6 in its free state, to lowering the intermediatemovable frame 7 to be placed close to thelower frame 3, tugging thewire rope 8 while keeping thehydraulic cylinder 6 in its inextensible state to pull up the intermediatemovable frame 7 toward theupper frame 5, thus to cause both theshells 2 to be mutually closed. - However, in a case where adhesional materials such as high viscous powdered ore and clay soil, which are easily adhesive to the inside of the grab, are handled by using the aforementioned conventional single-rope grab bucket, the adhesional materials adhered to the grab are not easily released even by opening the grab. Accordingly, the conventional grab bucket entailed a disadvantage such that the subsequent grabbing work cannot but seize hold of the adhesional materials while allowing the adhesional materials adhered to the grab, consequently to decreasing the working efficiency.
- This invention is made to eliminate the drawbacks suffered by the conventional grab bucket as described above and seeks to provide a grab bucket capable of successfully releasing materials grabbed even if the materials held inside are easily adhesive to the inside of the grab bucket.
- To attain the object described above according to the present invention, there is provided a grab bucket comprising a pair of shells opposed to each other in their openable state for constituting a grab, a lower frame for pivotably supporting the shells, an upper frame placed above the lower frame and connected with the backs of the shells through suspending arms, an intermediate movable frame placed between the upper and lower frames and connected with the lower frame through a hydraulic cylinder, a wire rope for suspending and dosing the grab, which wire pope has the lower end fixed onto the intermediate movable frame and runs through sheaves mounted on the intermediate movable frame and the upper frame, and a by-pass passage for connecting the upper end portion of the hydraulic cylinder with the cylinder body of the hydraulic cylinder to accelerate a piston movable between the upper end portion and the cylinder body of the hydraulic cylinder.
- It is desirable to place a control valve for regulating the flow of oil in the by-pass passage. The shells may preferably be formed so that their inner bottoms are inclined up inwardly when opening the grab. The shells may preferably have the inside made of stainless steel.
- Other and further objects of this invention will become obvious upon an understanding of the illustrative embodiments about to be described or will be indicated in the appended claims, and various advantages not referred to herein will occur to one skilled in the art upon employment of the invention in practice.
- One way of carrying out the invention is described in detail below with reference to drawings, which illustrate only one specific embodiment, in which:-
- FIG. 1 is a front view showing one embodiment of a grab bucket according to the present invention.
- FIG. 2 is a side view of FIG. 1.
- FIG. 3 is a front view showing the grab bucket of FIG. 1, in its opening state.
- FIG. 4 is a perspective view showing the state in which a wire rope runs sheaves in the grab bucket of the invention.
- FIG. 5 is a longitudinal cross-sectional view showing a hydraulic cylinder in the grab bucket of the invention.
- FIG. 6 is a schematic view showing an oil hydraulic circuit in the grab bucket of the invention.
- FIG. 7 is a front view showing a conventional grab bucket.
- FIG. 8 is a side view showing the conventional grab bucket of FIG. 7.
- One preferred embodiment of the grab bucket according to the present invention will be described hereinafter with reference to FIGS. 1 through 6 of the accompanying drawings. In describing the embodiment of the present invention, the same parts as in the conventional grab bucket described above are not described for the sake of simplicity in description.
-
- In the drawings,
reference numeral 1 denotes a grab, 3 a lower frame, 4 suspending arms, 5 an upper frame, 6 a hydraulic cylinder, 7 an intermediate movable frame, and 8 a wire rope. - That is, similarly to the prior art grab bucket as described above, the grab bucket of this invention comprises a pair of
shells 2 opposed to each other in their openable state for constituting thegrab 1, thelower frame 3 for pivotably supporting theshells 2, which is rotatable around axial shafts 3a, theupper frame 6 placed above thelower frame 3 and connected with the backs of theshells 2 through suspendingarms 4, the intermediatemovable frame 7 placed between the upper and lower frames and connected with thelower frame 3 through thehydraulic cylinder 6, thewire rope 8 for suspending and closing the grab, which has the lower end fixed onto the intermediatemovable frame 7 and runs through sheaves mounted on the intermediatemovable frame 7 and theupper frame 5, and a control means for controlling thehydraulic cylinder 6 by opening or closing an oil passage leading to the interior of thehydraulic cylinder 6. - The
grab 1 is constituted by theshells 2 supported on thelower frame 3 rotatably around the axial shafts 3a. When the shells mesh together to assume their closed state, a grabbingspace 9 for seizing hold of a pile of wood chips, crushed ore, earth, sand, wastes, scrap, rubbish and other fragmentary materials is formed therebetween. - Each
shell 2 has an inner surface made of stainless steel and aninner bottom 10 which assumes its posture inclined slightly inward and perpendicularly to the surface of the earth when the grab is opened fully. - The lower end of the suspending
arm 4 is rotatably joined to the back of eachshell 2, and the upper end of the suspendingarm 4 is rotatably joined to theupper frame 5, so that theshells 2 are suspended from theupper frame 5. - On the
lower frame 3, there are mounted an oil tank 11 and a radio-signal receiver 12. In the accompanying drawings,reference numeral 13 denotes an oil port formed in the upper portion of the oil tank 11, andreference numeral 14 denotes a receiving antenna for the radio-signal receiver 12. - The radio-
signal receiver 12 issues a command to open an oil hydraulic circuit for controlling thehydraulic cylinder 6 upon reception of a signal from the radio-signal receiver. - The intermediate
movable frame 7 is formed so as to define ahollow space 15 thereinside. On its front lower right side and rear lower left side of the intermediatemovable frame 7, there are fixedsheave cases 16 containingrotatable sheaves 17. - The
hydraulic cylinder 6 is provided with acylinder body 6a, apiston 6b reciprocatively contained within thecylinder body 6a, and apiston rod 6c connected with thepiston 6b and retractably protruding upward from thecylinder body 6a. - The lower end of the
cylinder body 6a is joined to thelower frame 3, and the leading end of thepiston rod 6b is joined to the top portion of the intermediatemovable frame 7 by using a bolt or other fixing means, so that thelower dame 3 is connected with the intermediatemovable frame 7 through thehydraulic cylinder 6. - The
piston 6b haspassages 18 passing from the upper side through to the lower side thereof. Within eachpassage 18, acheck valve 19 is disposed for regulating the flow of the oil passing from the upper side to the lower side of thepiston 6b. - The
piston rod 6c elongates upward from thepiston 6b. - As shown in FIG. 6, the oil hydraulic circuit for controlling the operation of the
hydraulic cylinder 6 includes a conduit pipe, which is connected at its one end with the upper part of thecylinder body 6a of thehydraulic cylinder 6 and at the other end thereof with the lower part of the cylinder body through athrottle valve 21 and apilot check valve 22. With the lower part of thecylinder body 6a, there is connected a connectingpipe 23 leading to the oil tank 11. - The
throttle valve 21 is interposed between the upper part of thecylinder body 6a and thepilot check valve 22, so as to regulate the flow of the oil flowing from the upper part to the lower part of thecylinder body 6a. - The
pilot check valve 22 is opened and closed by means of anelectromagnetic valve 24. When thepilot check valve 22 is dosed, the oil within the upper chamber defined above thepiston 6b in thepiston body 6a is prevented from flowing to restrain thehydraulic cylinder 6 from moving downward. When thepilot check valve 22 is open, the oil is allowed to flow into the lower chamber defined below thepiston 6b in thehydraulic cylinder 6 through theconduit pipe 20, thus to bring thehydraulic cylinder 6 into its free state. - The
hydraulic cylinder 6 is further provided with a by-pass passage 25 for accelerating thepiston 6b. The by-pass passage 25 connects the upper portion of thecylinder body 6a with a portion apart from the upper portion at a prescribed distance through a by-pass conduit pipe 26. - The by-
pass conduit pipe 26 includes athrottle valve 27 for regulating the flow of the oil passing therethrough. - The
upper frame 5 is formed so as to allow the intermediatemovable frame 7 to enter into the central portion thereof. Theupper frame 5 is further provided on its front and rear sides with rotatingsheaves 28. - The intermediate
movable frame 7 is suspended from theupper frame 5 and vertically movable by operating thewire rope 8. That is, as shown in FIG. 4, thewire rope 8 has the lower ends connected with both sides of the intermediatemovable frame 7 and run through thesheaves 28 on theupper frame 5 and thesheaves 17, and the upward elongated part of the wire rope is caught on ahook 29. - Next, the opening and closing operations of the
grab 1 and thehydraulic cylinder 6 of the grab bucket of the invention will be described - Initially, the
grab 1 assumes its closed state in which the upper and lower frames and intermediate movable frame are close to one another and is suspended from a crane or the like. - At this time, the
pilot check valve 22 of the oil hydraulic circuit is closed to prevent the oil in thehydraulic cylinder 6 from flowing, thus to bring thehydraulic cylinder 6 to a deadlock. - To open the
grab 1, a grab-opening command is first transmitted to the radio-signal receiver 12 to apply an operating current to an electromagnetic valve (solenoid valve) 24. Thereupon, theelectromagnetic valve 24 is actuated to form a passage to the pilot check valve while the operating current flows. - As the result of actuating the
electromagnetic valve 24, thepilot check valve 22 opens to allow the oil to flow the upper chamber to the lower chamber in thecylinder body 6a through theconduit pipe 20, thus to bring the hydraulic cylinder into its free state. - Consequently, the
lower frame 3 is separated from the intermediatemovable frame 7 and moves downward by its own weight, thus to lower the position of the axial shaft 3a while the rear of eachshell 2 is suspended from the suspendingarm 4, as the result of which thegrab 1 is opened. - At this time, the
hydraulic cylinder 6 is expanded to move thepiston 6b upward in thecylinder body 6a. When thepiston 6b reaches the point connected to the by-pass conduit pipe 26, i.e. the position depicted by the chain line in FIG. 5, the by-pass passage 25 is opened to permit the oil to flow from the upper chamber to the lower chamber in the cylinder body. Consequently, the amount of the oil flowing into the lower chamber of the cylinder body is increased to speed up the expansion of thehydraulic cylinder 6. Thus, the opening speed of the grab is accelerated from the open state indicated by the imaginary line (alternate long and short dash line) until the full-open state indicated by the solid line in FIG. 3. - As described above, since the expansion rate of the
hydraulic cylinder 6 is increased to accelerate the opening speed of the grab, even the grabbed fragmentary materials sticking to the inner surfaces of the shells can be efficiently thrown off by the action of inertia. The acceleration of the opening speed can be controlled by regulating thethrottle valve 27. - Then, the
grab 1 is landed on an object to be grabbed as it is kept in its open state. Thereafter, thegrab 1 in the open state is closed in such a manner that thewire rope 8 is let out downward while keeping thehydraulic cylinder 6 in the free state, thereby to lower the intermediatemovable frame 7 toward thelower frame 3, and then, thewire rope 8 is pulled up to permit thelower frame 7 to approach theupper frame 5 while keeping thehydraulic cylinder 6 in its inextensible state. As a result, the axial shafts 3a are moved upward to close theshells 2. - At this time, the
pilot check valve 22 is closed to prevent the oil in the upper chamber in thecylinder body 6a from flowing into the lower chamber, thus to restrain the hydraulic cylinder from expanding. On the other hand, the oil in the lower chamber in the cylinder body flows into the upper chamber of the cylinder body through theoil passage 18 formed in thepiston 6b. Consequently, thehydraulic cylinder 6 is shortened, holding its cushion effect. - The
throttle valve 27 in the by-pass passage 25 is controlled taking stickiness of the objective materials to be grabbed by the grab. Ordinarily, thehydraulic cylinder 6 may be used as usual in such a manner that thethrottle valve 27 is closed to dose the by-pass passage 25. - In the embodiment described above, a wireless control system for controlling the electromagnetic valve is used, but a wired control system may be substituted in place of the wireless system.
- As is apparent from the foregoing description, the grab bucket according to the present invention comprises the grab formed of the paired shells opposed to each other in their openable state, the lower frame for pivotably supporting the shells, the upper frame placed above the lower frame and connected with the shells through the suspending arms, the intermediate movable frame placed between the upper and lower frames and connected with the lower frame through the hydraulic cylinder, the wire rope for suspending and closing the grab, and the by-pass passage for connecting the upper end portion of the hydraulic cylinder with the cylinder body of the hydraulic cylinder to accelerate the piston movable between the upper end portion and the cylinder body of the hydraulic cylinder. The wire pope has the lower end fixed onto the intermediate movable frame and runs through sheaves mounted on the intermediate movable frame and the upper frame. According to the grab bucket of the present invention, the opening speed of the grab can be varied, so that the scrap or other objective materials grabbed by the grab bucket of the invention can be efficiently thrown off by vibration and the action of inertia of the objective materials only by fully opening the grab. Thus, according to the grab bucket of the invention, the work of grabbing a pile of wood chips, crushed ore, earth, sand, wastes, scrap, rubbish, and any other materials can effectively operated
- Furthermore, since the grab bucket according to the invention is provided with the control valve for regulating the flow of oil in the by-pass passage, the opening speed of the grab can readily be controlled so as to throw off materials grabbed by the grab bucket, while controlling the impact caused when opening the grab with holding the cushion effect of the hydraulic cylinder. In a case of grabbing materials easy to release, the control valve may be dosed to restrain a shock from occurring when releasing the grabbed materials.
- Besides, since the bottoms of the shells in the grab bucket according to the invention are inclined inward and upward, the materials grabbed by the grab of the invention can easily be thrown off when opening the grab. By providing the shells with the inner surfaces of stainless steel, the materials grabbed by the grab can more easily be thrown off
Claims (4)
- A grab bucket comprising a pair of shells (2) opposed to each other in their openable state for constituting a grab (1), a lower frame (3) for pivotably supporting said shells (2), an upper frame (5) placed above said lower frame (3) and connected with the backs of said shells (2) through suspending arms (4), an intermediate movable frame (7) placed between said upper and lower frames and connected with said lower frame through a hydraulic cylinder (6), and a wire rope (8) for suspending and closing said grab (1), said wire pope having a lower end fixed onto said intermediate movable frame (7) and running through sheaves mounted on said intermediate movable frame and said upper frame (5),
characterised by a by-pass passage (25) connecting an upper end portion of said hydraulic cylinder (6) with the cylinder body of said hydraulic cylinder operative to allow a piston (6b) movable between said upper end portion and said cylinder body of said hydraulic cylinder (6) to accelerate. - A grab bucket as claimed in claim 1, further comprising a throttle valve (27) disposed in said by-pass passage (25).
- A grab bucket as claimed in claim 1 or claim 2, wherein each of said shells (2) has an inner bottom assuming its posture inclined slightly inward and upward.
- A grab bucket as claimed in any of claims 1 to 3, wherein each of said shells (2) has an inner surface made of stainless steel.
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP2000357647A JP3385379B2 (en) | 2000-11-24 | 2000-11-24 | Grab bucket |
JP2000357647 | 2000-11-24 |
Publications (1)
Publication Number | Publication Date |
---|---|
EP1211356A1 true EP1211356A1 (en) | 2002-06-05 |
Family
ID=18829670
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP01309894A Withdrawn EP1211356A1 (en) | 2000-11-24 | 2001-11-23 | Grab bucket |
Country Status (2)
Country | Link |
---|---|
EP (1) | EP1211356A1 (en) |
JP (1) | JP3385379B2 (en) |
Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN101979304A (en) * | 2010-11-05 | 2011-02-23 | 无锡市新华起重工具有限公司 | Remote control grab bucket |
CN102398853A (en) * | 2010-09-14 | 2012-04-04 | 沈阳铝镁设计研究院有限公司 | Power-free grab bucket |
WO2023045221A1 (en) * | 2021-09-27 | 2023-03-30 | 云南锡业股份有限公司锡业分公司 | Apparatus and method for efficiently separating crude b-tin from molten crude tin |
Families Citing this family (6)
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JP4912966B2 (en) * | 2007-06-21 | 2012-04-11 | Jx日鉱日石エネルギー株式会社 | Valve opening indicator |
JP4618589B2 (en) * | 2009-06-09 | 2011-01-26 | 東部重工業株式会社 | Hydraulic control cylinder device for single rope type grab bucket |
CN102070077A (en) * | 2009-10-29 | 2011-05-25 | 日立建机株式会社 | Grab |
CN104291214A (en) * | 2014-08-26 | 2015-01-21 | 上海港怡动力***有限公司 | Remote control grab bucket capable of discharging in stable mode |
CN108118729A (en) * | 2016-11-28 | 2018-06-05 | 广西大学 | It is a kind of that multi link timber grab is driven using Dual-Servo Motor |
CN113184693B (en) * | 2021-05-24 | 2022-04-05 | 安徽马钢矿业资源集团姑山矿业有限公司 | Deep-digging grab bucket structure for mine field traveling crane |
Citations (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
BE438552A (en) * | ||||
US3985384A (en) * | 1975-09-29 | 1976-10-12 | Mcginnes Manufacturing Company | Hydraulic apparatus for grab device |
US4381872A (en) * | 1981-03-26 | 1983-05-03 | Mcginnes Manufacturing Company | Remote controlled clamshell bucket apparatus and method of using same |
US4773689A (en) * | 1986-05-22 | 1988-09-27 | Wirth Maschinen-Und Bohrgerate-Fabrik Gmbh | Apparatus for clamping to the end of a pipe |
DE4327463A1 (en) * | 1993-08-16 | 1995-03-02 | Salzgitter Maschinenbau | Grab for a hoisting mechanism (lifting mechanism, crane) |
-
2000
- 2000-11-24 JP JP2000357647A patent/JP3385379B2/en not_active Expired - Lifetime
-
2001
- 2001-11-23 EP EP01309894A patent/EP1211356A1/en not_active Withdrawn
Patent Citations (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
BE438552A (en) * | ||||
US3985384A (en) * | 1975-09-29 | 1976-10-12 | Mcginnes Manufacturing Company | Hydraulic apparatus for grab device |
US4381872A (en) * | 1981-03-26 | 1983-05-03 | Mcginnes Manufacturing Company | Remote controlled clamshell bucket apparatus and method of using same |
US4773689A (en) * | 1986-05-22 | 1988-09-27 | Wirth Maschinen-Und Bohrgerate-Fabrik Gmbh | Apparatus for clamping to the end of a pipe |
DE4327463A1 (en) * | 1993-08-16 | 1995-03-02 | Salzgitter Maschinenbau | Grab for a hoisting mechanism (lifting mechanism, crane) |
Cited By (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN102398853A (en) * | 2010-09-14 | 2012-04-04 | 沈阳铝镁设计研究院有限公司 | Power-free grab bucket |
CN102398853B (en) * | 2010-09-14 | 2013-05-01 | 沈阳铝镁设计研究院有限公司 | Power-free grab bucket |
CN101979304A (en) * | 2010-11-05 | 2011-02-23 | 无锡市新华起重工具有限公司 | Remote control grab bucket |
CN101979304B (en) * | 2010-11-05 | 2012-09-12 | 无锡市新华起重工具有限公司 | Remote control grab bucket |
WO2023045221A1 (en) * | 2021-09-27 | 2023-03-30 | 云南锡业股份有限公司锡业分公司 | Apparatus and method for efficiently separating crude b-tin from molten crude tin |
Also Published As
Publication number | Publication date |
---|---|
JP2002160890A (en) | 2002-06-04 |
JP3385379B2 (en) | 2003-03-10 |
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