CA1120076A - Excavator with a clamshell bucket having magnified vertical stroke - Google Patents
Excavator with a clamshell bucket having magnified vertical strokeInfo
- Publication number
- CA1120076A CA1120076A CA000330276A CA330276A CA1120076A CA 1120076 A CA1120076 A CA 1120076A CA 000330276 A CA000330276 A CA 000330276A CA 330276 A CA330276 A CA 330276A CA 1120076 A CA1120076 A CA 1120076A
- Authority
- CA
- Canada
- Prior art keywords
- pulley
- pulleys
- boom
- excavator
- rope
- 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.)
- Expired
Links
Classifications
-
- 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
- B66C3/12—Grabs actuated by two or more ropes
- B66C3/125—Devices for control
-
- 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
-
- E—FIXED CONSTRUCTIONS
- E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
- E02F—DREDGING; SOIL-SHIFTING
- E02F9/00—Component parts of dredgers or soil-shifting machines, not restricted to one of the kinds covered by groups E02F3/00 - E02F7/00
- E02F9/20—Drives; Control devices
- E02F9/2016—Winches
Landscapes
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Mining & Mineral Resources (AREA)
- Civil Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Structural Engineering (AREA)
- Jib Cranes (AREA)
- Earth Drilling (AREA)
- Load-Engaging Elements For Cranes (AREA)
Abstract
AN EXCAVATOR WITH A CLAMSHELL BUCKET HAVING MAGNIFIED VERTICAL
STROKE
ABSTRACT OF THE DISCLOSURE
An excavator having a base structure, a boom pivotally supported at its lower end by the base structure, an arm pivotally supported near its root end by the upper end of the boom, and a clamshell bucket suspended from the tip end of the arm by pulley and rope systems extended along the arm and the boom so as to provide more parts of the ropes to the parts extended between the tip end of the arm and the bucket as the boom is more inclined downward.
STROKE
ABSTRACT OF THE DISCLOSURE
An excavator having a base structure, a boom pivotally supported at its lower end by the base structure, an arm pivotally supported near its root end by the upper end of the boom, and a clamshell bucket suspended from the tip end of the arm by pulley and rope systems extended along the arm and the boom so as to provide more parts of the ropes to the parts extended between the tip end of the arm and the bucket as the boom is more inclined downward.
Description
- 2 -BACKGROUND OF THE INVENTION
The present invention relates to an excavator which employs a clamshell bucket as an e~cavating head.
As a relatively small-sized excavator is known an excavator ~hich has a base structure including a vehicle structure such as a caterpillar tractor, a boom having a lower and an upper end and pivotally supported at the lower end by the base structure around a first axis, an arm having a root and a tip end and pivotally supported near the root end by the upper end of the boom around a second axis, a clamshell bucket which includes a hydraulically operated shell opening and closing mechanism and which is attached to the tip end of the arm, a means for turning the boom relative to the base structure around the first axis, and a means for turning the arm relative to the boom around the second axis.
Although an excavator of this type has advantages that it is simple in structure and easy to operate, it has the drawback that the depth of excavation available by this excavator, which is determined by the total length of a link mechanism composed of the boom, the arm, and the clamshell bucket, is relatively small.
In this case, of course, the depth reached by the clamshell bucket would be optionally increased if the clamshell bucket were suspended via a piece of rope or the like from the tip end of the arm. However, in such a case it will not be possible directly to load earth or the like excavated by the clamshell bucket onto a dump truck or other transporting means, and perhaps the clamshell bucket will not even be directly lifted up out of the hole. In other words, the stroke of the bucket is not increased by this suspension.
SUMMARY OF THE INVENTION
It is therefore the object of the present inventlon to . ,- .
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~ 3 -~2~ 7~i provide an excavator which is comparable in simplicity of structure and ease of operation to the aforementioned conventional excavator having a base structure, a boom, a clamshell bucket, and means for operating the boom and the arm, and yet which provides a substantially larger depth of excavation than the aforementioned conventional excavator.
In accordance with the present invention, the abovementioned object is accomplished by an excavator comprising: a base structure; a boom having a lower and upper end and pivotally supported around a first axis at its lower end by the base structure and inclining in a certain direction; a means for turning the boom around the first axis with respect to the base structure; an arm having a root and a tip end and pivotally supported around a second axis near its root end by the upper end of the boom; a means for turning the arm around the second axis with respect to the boom; a clamshell bucket having a suspension frame and a rope-operated shell opening and closing mechanism; a first pulley and rope system including a first pulley mounted rotatably at the tip end of the arm, a second pulley mounted rotatably on the boom at a position substantially distant from the first axis, and a first rope, which is connected at one of its ends to the suspension frame of the clamshell bucket, and which is extended over, in order from this end, the first and - second pulleys, and which then bears against the base structure at a base bearing point substantially distant from the first axis and spaced therefrom in the direction of inclination of the boom, the force of its tension being supported by the base structure at this base bearing point, and which is connected at its other end to either the base structure or the boom; and a second pulley and rope system including a third pulley mounted rotatably at the tip end of the arm substantially coaxially with the first pulley, a cylinder-piston actuator having a fixed and a movable end and supportedat the fixed end by the arm, a fourth pulley mounted rotatably ~ ~ " ~ ~ .
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at the movable end of the actuator, a fifth pulley supported by the arm, a sixth pulley supported by the boom substantially coaxially with -the second pulley, and a second rope, which is connected at one of its ends to the shell opening and closing mechanism, and which is extended over, in order from this end, the third, fourth, fifth, and sixth pulleys, and which then bears against the base structure at a point substantially the same as the base bearing pointl and which is connected at its other end to either the base structure or the boom.
-In an excavator of the aforementioned structure, as theboom is inclined from a relatively upright position downwards towards the horizontal, and further downwards towards a downwardly inclined position, so as to lower the clamshell bucket to the bottom of a hole to be excavated, the spans of the first and second ropes extended between their fixed end points and the second and sixth pulleys, respectively, are gradually shortened, so that the spans of the first and second ropes extended between the first pulley and the suspension frame of the clamshell bucket and between the third pulley and the shell opening and closing mechanism of the clamshell bucket, respectively, are gradually increased, whereby the maximum depth which can be reached by the clamshell bucket is correspondingly increased.
In order to magnify the effect of increasing excavating ~-depth obtained by the excavator of the present invention, the first and second pulley and rope systems may further comprise first and second sheave systems respectively, extended between a point on the base structure substantially remote from the first axis and a point on the boom substantially remote from the first axis, so that the first and second ropes are conducted through the first and second sheave systems in their parts between the second and sixth pulleys and their said other ends, xespectively.
; . .
.
.. . .
-~ 5 7~ii When the said other ends of the first and second ropes are connected to the base structure, the bearing points of the ropes on the base structure may be the connecting points of the ropes to the base structure. On the other hand, when the said other ends of the first and second ropes are connected to the boom, the bearing points of the ropes on the base structure need to comprise pulleys which support the first and second ropes from the base structure.
When the first and second sheave systems are provided, the second and sixth pulleys may be integrated in the first and second sheave systems, respectively. Further, the first and second sheave systems may be integrally combined.
The second pulley and rope system may further comprise a third sheave system extended between the tip end of the arm and the movable end of the cylinder-piston actuator, so that the second rope is conducted through this third sheave system in its part between the third and fifth pulleys, whereby the output force required for the cylinder-piston actuator is increased, but its piston stroke decreases.
In an excavator of the abovementioned structure, the deepest possible excavation is performed when the boom is inclined downwards to its extreme position, and the arm is extended vertically downwards. In this state of operation, the first and the second ropes, if they were directly extended between the first and the second pulleys and between the fifth and sixth pulleys, respectively, would interfere with the edge of the hole. In view of this, it is desirable that the first and second pulley and rope systems should further comprise seventh and eighth pulleys respectively, rotatably supported by the arm, so that the first rope is extended over the seventh pulley in its part between the first and second pulleys, while the second rope is extended over the eighth pulley in its part between the fifth and sixth pulleys.
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In order to increase the stability of the clamshell bucket while it is suspended by the first rope, it is desirable that the first pulley and rope system should be provided in duplicate.
BRIEF DESCRIPTION OF T~E DRAWINGS
The present invention will become more fully understood from the detailed description of several embodiments given hereinbelow, and the accompanying drawings, which are given by way of illustration only, and thus are not limitative of the present invention, and wherein:
Fig. 1 is a side view of an embodiment of the excavator according to the present invention;
Fig. 2 is a front view of the clamshell bucket and some related portions in the excavator shown in Fig. 1, as viewed along an arrow II in Fig. l;
Fig. 3 is a somewhat enlarged side view of the arm portion of the excavator shown in Fig. l;
Fig. 4 is a front view of the arm portion shown in Fig.
The present invention relates to an excavator which employs a clamshell bucket as an e~cavating head.
As a relatively small-sized excavator is known an excavator ~hich has a base structure including a vehicle structure such as a caterpillar tractor, a boom having a lower and an upper end and pivotally supported at the lower end by the base structure around a first axis, an arm having a root and a tip end and pivotally supported near the root end by the upper end of the boom around a second axis, a clamshell bucket which includes a hydraulically operated shell opening and closing mechanism and which is attached to the tip end of the arm, a means for turning the boom relative to the base structure around the first axis, and a means for turning the arm relative to the boom around the second axis.
Although an excavator of this type has advantages that it is simple in structure and easy to operate, it has the drawback that the depth of excavation available by this excavator, which is determined by the total length of a link mechanism composed of the boom, the arm, and the clamshell bucket, is relatively small.
In this case, of course, the depth reached by the clamshell bucket would be optionally increased if the clamshell bucket were suspended via a piece of rope or the like from the tip end of the arm. However, in such a case it will not be possible directly to load earth or the like excavated by the clamshell bucket onto a dump truck or other transporting means, and perhaps the clamshell bucket will not even be directly lifted up out of the hole. In other words, the stroke of the bucket is not increased by this suspension.
SUMMARY OF THE INVENTION
It is therefore the object of the present inventlon to . ,- .
: : , : . . :- ., .
:~ , : . . ,. - : .
, ' . ` ' .
~ 3 -~2~ 7~i provide an excavator which is comparable in simplicity of structure and ease of operation to the aforementioned conventional excavator having a base structure, a boom, a clamshell bucket, and means for operating the boom and the arm, and yet which provides a substantially larger depth of excavation than the aforementioned conventional excavator.
In accordance with the present invention, the abovementioned object is accomplished by an excavator comprising: a base structure; a boom having a lower and upper end and pivotally supported around a first axis at its lower end by the base structure and inclining in a certain direction; a means for turning the boom around the first axis with respect to the base structure; an arm having a root and a tip end and pivotally supported around a second axis near its root end by the upper end of the boom; a means for turning the arm around the second axis with respect to the boom; a clamshell bucket having a suspension frame and a rope-operated shell opening and closing mechanism; a first pulley and rope system including a first pulley mounted rotatably at the tip end of the arm, a second pulley mounted rotatably on the boom at a position substantially distant from the first axis, and a first rope, which is connected at one of its ends to the suspension frame of the clamshell bucket, and which is extended over, in order from this end, the first and - second pulleys, and which then bears against the base structure at a base bearing point substantially distant from the first axis and spaced therefrom in the direction of inclination of the boom, the force of its tension being supported by the base structure at this base bearing point, and which is connected at its other end to either the base structure or the boom; and a second pulley and rope system including a third pulley mounted rotatably at the tip end of the arm substantially coaxially with the first pulley, a cylinder-piston actuator having a fixed and a movable end and supportedat the fixed end by the arm, a fourth pulley mounted rotatably ~ ~ " ~ ~ .
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at the movable end of the actuator, a fifth pulley supported by the arm, a sixth pulley supported by the boom substantially coaxially with -the second pulley, and a second rope, which is connected at one of its ends to the shell opening and closing mechanism, and which is extended over, in order from this end, the third, fourth, fifth, and sixth pulleys, and which then bears against the base structure at a point substantially the same as the base bearing pointl and which is connected at its other end to either the base structure or the boom.
-In an excavator of the aforementioned structure, as theboom is inclined from a relatively upright position downwards towards the horizontal, and further downwards towards a downwardly inclined position, so as to lower the clamshell bucket to the bottom of a hole to be excavated, the spans of the first and second ropes extended between their fixed end points and the second and sixth pulleys, respectively, are gradually shortened, so that the spans of the first and second ropes extended between the first pulley and the suspension frame of the clamshell bucket and between the third pulley and the shell opening and closing mechanism of the clamshell bucket, respectively, are gradually increased, whereby the maximum depth which can be reached by the clamshell bucket is correspondingly increased.
In order to magnify the effect of increasing excavating ~-depth obtained by the excavator of the present invention, the first and second pulley and rope systems may further comprise first and second sheave systems respectively, extended between a point on the base structure substantially remote from the first axis and a point on the boom substantially remote from the first axis, so that the first and second ropes are conducted through the first and second sheave systems in their parts between the second and sixth pulleys and their said other ends, xespectively.
; . .
.
.. . .
-~ 5 7~ii When the said other ends of the first and second ropes are connected to the base structure, the bearing points of the ropes on the base structure may be the connecting points of the ropes to the base structure. On the other hand, when the said other ends of the first and second ropes are connected to the boom, the bearing points of the ropes on the base structure need to comprise pulleys which support the first and second ropes from the base structure.
When the first and second sheave systems are provided, the second and sixth pulleys may be integrated in the first and second sheave systems, respectively. Further, the first and second sheave systems may be integrally combined.
The second pulley and rope system may further comprise a third sheave system extended between the tip end of the arm and the movable end of the cylinder-piston actuator, so that the second rope is conducted through this third sheave system in its part between the third and fifth pulleys, whereby the output force required for the cylinder-piston actuator is increased, but its piston stroke decreases.
In an excavator of the abovementioned structure, the deepest possible excavation is performed when the boom is inclined downwards to its extreme position, and the arm is extended vertically downwards. In this state of operation, the first and the second ropes, if they were directly extended between the first and the second pulleys and between the fifth and sixth pulleys, respectively, would interfere with the edge of the hole. In view of this, it is desirable that the first and second pulley and rope systems should further comprise seventh and eighth pulleys respectively, rotatably supported by the arm, so that the first rope is extended over the seventh pulley in its part between the first and second pulleys, while the second rope is extended over the eighth pulley in its part between the fifth and sixth pulleys.
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In order to increase the stability of the clamshell bucket while it is suspended by the first rope, it is desirable that the first pulley and rope system should be provided in duplicate.
BRIEF DESCRIPTION OF T~E DRAWINGS
The present invention will become more fully understood from the detailed description of several embodiments given hereinbelow, and the accompanying drawings, which are given by way of illustration only, and thus are not limitative of the present invention, and wherein:
Fig. 1 is a side view of an embodiment of the excavator according to the present invention;
Fig. 2 is a front view of the clamshell bucket and some related portions in the excavator shown in Fig. 1, as viewed along an arrow II in Fig. l;
Fig. 3 is a somewhat enlarged side view of the arm portion of the excavator shown in Fig. l;
Fig. 4 is a front view of the arm portion shown in Fig.
3, as viewed along an arrow IV;
-Fig. 5 is a view similar to a part of Fig. 3, showing a modificatlon of the structure shown in Fig. 3;
30Fig. 6 is a view which shows the entire pulley and rope system of the excavator shown in Fig. 1, in development;
Fig. 7 is a diagrammatical perspective view showing the entire pulley and rope system of the excavator shown in Fig.
1;
Fig. 8 is a view similar to Fig. 1, showing another embodiment .
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, , ~ Z~07~i of the excavator according to the present invention;
Fig. 9 is a somewhat enlarged side view of the arm portion of the excavator shown in Fig. 8;
Fig. 10 is a front view of the arm portion shown in Fig. 9, as viewed along an arrow X;
Fig. 11 is a view which shows the entire pulley and rope system of the excavator shown in Fig. 8, in development;
and -J Fig. 12 is a diagrammatical perspective view showing the entire pulley and rope system of the excavator shown in 15 Fig 8.
DESCRIPTION OF THE PREFERRED E~sODIMENTS
Referring first to Figs. 1 and 2 for the general structure 20 of the excavator according to the present invention, this excavator comprises a base structure 10, which, in this embodiment, is a vehicle body equipped with caterpillar tracks. A boom 11, which in this embodiment has a slightly bent shape, and which has a lower end lla and an upper end 25 llb, is pivotally supported at the lower end lla by the base structure 10, via a pivot shaft 10a, around a first axis.
The boom 11 is rotated around the pivot shaft 10a relative to the base structure 10 by a hydraulic cylinder-piston actuator 12 mounted between the base structure 10 and the 30 boom 11 by pivot shafts 12a and 12b. At the upper end llb of the boom 11 is pivotally supported the root end 14a of an arm 14, via a pivot shaft 13, about a second axis. The arm 14 is rotated around the pivot shaft 13 relative to the boom 11 by a hydraulic cylinder-piston actuator 15, which is mounted between the boom 11 and the very extremity of the root end 14a of the arm 14 by pivot shafts 15a and 16. The arm 14 has a tip end 14b, from which a clamshell bucket 30 .
, .-is suspended as explained in detail hereinunder.
Turning now to Figs. 3 and 4, together with Figs. 1 and2, a pulley and rope system incorporated in the arm portion of the excavator will be explained. 40 designates generally a means for opening and closing the clamshell bucket 30.
This means includes a hydraulic cylinder-piston actuator 20, which has a fixed end 20a which is pivotally mounted to the arm 14 by a pivot means 16a, and a movable end 20b connected with an oblique block 41 by way of a fitting 49. The oblique block 41 has a base plate 41a, and opposite side plates 41b, 41b between which are rotatably mounted three obliquely aligned pulleys 48a, 48b, and 48c properly spaced from each other by a shaft 47 supported by said side plates at opposite ends thereof and spacer means not shown in the figure.
On the upper surface of the arm 14 and adjacent to its tip end 14b is mounted a straight pulley block 51 by its bottom plate 51a, from which are supported a pair of side plates 51b, 51b, between which are rotatably mounted three straight-aligned pulleys 53a, 53b and 53c properly spaced from each other by a shaft 52 supported by said side plates at opposite ends thereof and by spacers. The obliquely aligned pulleys 48a, etc. and the straight-aligned pulleys 53a, etc. form mutually co-operating pulley systems, wherein these pulleys are so arranged that the peripheral portions closest to the viewer, as seen in Fig. 4, of the grooves of the pulleys 48a - 48c are in alignment with the peripheral portions closest to the viewer, as seen in Fig. 4, of the grooves of the pulleys 53a - 53c, respectively, while the peripheral portions furthest from the viewer, as seen in Fig~ 4, of the grooves of the pulleys 48a and 48b are in alignment with the peripheral portions furthest from the viewer, as seen in Fig. 4, of the grooves of the pulleys 53b and 53c, respectively.
From the tip end 14b of the arm 14 are extended a pair of side plates 54, 54 in parallel to each other, by which are supported shafts 61 and 62. At the outside and the inside :
.
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of the side plates 54, 54 are provided pulleys 63a, 63b, 63c, and 63d rotatably supported by the shaft 61 and properly spaced from each other by proper spacing means. In tnis case, the pulley 63b i5 in alignment with the pulley 53a, while the pulley 63c is in alignment with the peripheral portion furthest from the viewer, as seen in Fig. 4, of the groove of the pulley 48c. In alignment with the pulleys 63a, 63b and 63d are provided three pulleys 65a, 65b, and 65c rotatably supported by the shaft 62 and properly spaced from each other by proper spacing means.
~ A rope guide frame 70 having a pair of side plates 70a, 70a and a trans~erse plate 70b is connected to the shaft 61 so as to be rotatable therearound by the side plates 70a being pivotally mounted to the shaft 61. The transverse plate 70b of the rope guide frame has an opening defined by a bush 71 which is in alignment with the pulley 63b, and two other openings defined by bushes 72, 72 which are in alignment with the pulleys 63a and 63d, respectively.
As a modification of these structures, as shown in Fig.
5, a common bracket 68 which supports the shafts 52, 61 and 62 all together may be provided, so that the common bracket is mounted to the tip end 14b by fittings 18a and l9a.
Returning again to Fig. 3 and further referring to Fig.
6, on the lower face of the arm 14 between the second axis at 13 and the tip end 14b of tne arm is mounted a frame 74 with its bottom plate 74a, from which a pair of side plates 74b, 74b are extended. A shaft 75 is supported by the side plates 74b, 74b at its opposite ends, and three pulleys 76a, 76b, and 76c are rotatably mounted on the shaft 75 and are properly spaced from each other by spacing means~ In this case, as shown in Fig. 6, the pulleys 76a, 76b, and 76c are aligned with the pulleys 63a, 63c, and 63d, respectively.
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Referring to Figs. 1 and 6, a bucket stroke-magnifying mechanism generally designated by 80 is a plurality of sheave systems, and comprises a pair of frames 81 each supporting a pivot pin 82, a frame 83 includiny a bottom plate 83a and side plates 83b, a shaft 8~ supported by the side plates 83b, pulleys 85a, 85b, 85c, 85d, 85e, and 85f rotatably supported by the shaft 84 and properly spaced from each other, a pair of frames 86 each supporting a pivot pin 87, a link element 88 pivotally connecting the frame 83 to the base structure 10 by way of the pivot pins 82 and 87, a frame 89 having a bottom plate 89a and side plates 89b extending at right angles from the base plate 89a and mounted to a middle portion of the boom 11, a shaft 90 supported by the side plates 89b, pulleys 91a, 91b, 91c, 91d, 91e, and 91f rotatably supported by the shaft 90 and spaced properly from each other by spacing means, and ropes 98a, 98b, and 99 engaged with these pulleys. In this case, the pulleys 85a -85f are arranged obliquely, so that the peripheral portion of the groove furthest from the viewer of the pulley 85a and the peripheral portion of the groove closest to the viewer of the pulley 85b, each as seen in Fig. 6 (and similarly hereinunder), are in alignment with the groove of the pulley 91a, the peripheral portion furthest from the viewer of the groove of the pulley 85b is in alignment with the groove of the pulley 91b, the peripheral portion furthest from the v.iewer of the groove of the pulley 85c and the peripheral portion closest to the viewer of the groove of the pulley 85d are in alignment with the groove of the pulley 91c, the peripheral portion furthest from the viewer of 'he groove of the pulley 85d is in alignment with the groove of the pulley 91d, the peri.pheral portion furthest from the viewer of the groove of the pulley 85e and the peripheral portion closest to the viewer of the groove of the pulley 85f are in alignment with the groove of the pulley 91e, and the peripheral portion furthest from the viewer of the groove of the pulley 85f is in alignment with the groove of the pulley 91f. The wire ., . :. ~:
.
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98a is connected at its one end to the frame 89 at its wire holding element 89c and is extended over the pulleys 85a, 91a,- 85b, 91b, 76a, 65a, and 63a, is passed through the bush 72, and is connected at the other end thereof to a wire holding element 97 of the suspension frame 93 of the clamshell bucket 30. Similarly, the wire 98b is connected at its one end to the wire holding element 89c of the frame 89, is extended over the pulleys 85e, 91e, 85f, 91f, 76c, 65c, and 63d, is passed through the other bush 72, and is connected at its other end to the wire holding element 97 of the suspension frame 93 of the clamshell bucket 30. The wire 99 is connected at its one end to the wire holding element 89c of the frame 89, is extended over the pulleys 85c, 91c, 85d, 91d, 76b, 63c, 48c, 53c, 48b, 53b, 48a, 53a, 65b, and 63b, is passed through the bush 71, and is connected at its other end to the shell opening and closing mechanism 95 of the clamshell bucket 30. In this case, in more detail, the end portion of the rope 99 is passed through an opening defined by a bush 94 in the suspension frame 93 of the clamshell bucket 30, is extended over several pulleys of the shell opening and closing mechanism 95, and is connected to the rope holding element 96 of the suspension frame 93. A rope operated clamshell bucket such as the bucket 30 is itself well known in the art, and operates in such a manner that, when the rope 99 is pulled out from the shell opening and closing mechanism 95, the clamshell is closed, and when the rope 99 is fed to the shell opening and closing mechanism, the clamshell opens.
The abovementioned arrangement of the ropes 98a, 98b, and 99 is shown in ~ig. 7 in a diagrammatical perspective view. By this arrangement of pulleys and ropes, when the clamshell bucket 30 is opened by the rope 99 being loosened by expansion of the hydraulic cylinder piston actuator 20, the clamshell bucket 30 is suspended substantially by the pair of ropes 98a and 98b, and, when the clamshell bucket 30 ,: ~ ; ~, ~, .. ' .Zi~3~7~i is closed by the rope 99 being tightened by contraction of the actuator 20, the clamshell bucket 30 and generally the load supported by the bucket are suspended by the rope 99, while the pair of ropes 98a and 98b are maintained in a slightly loosened condition so that full closing of the bucket is ensured.
In operation, when the boom 11 is gradually more inclined from a position such as shown in Fig. 1, so as to lower the bucket 30 to the bottom of a hole which is being excavated, the distance between the pulleys 85a - 85f arld the pulleys 91a - 91f is gradually shortened, whereby more of the ropes 98a, 98b, and 99 is fed to the span portions of these ropes which extend between the tip of the arm 14 and the clamshell bucket 30, thereby increasing the depth of the hole whose bottom can be reached by the clamshell bucket, as compared with a conventional excavator having comparable dimensions with regard to the base structure 10, the boom 11, and the arm 14, under the condition that the bucket which is excavating the bottom of the hole must of course be taken out of the hole to dump the excavated matter onto a proper transportation means such as a dump truck or the like.
In other words, in the excavator according to the present invention, if the relative position between the boom 11 and the axm 14 is maintained constant, when the boom ll is rotated around the first axis about the pivot shaft lOa by means of the cylinder-piston actuator 12, the bucket 30 mo~es up and down for more than the up and down shift traversed by the tip end of the arm 14.
Thus the excavator of the present invention can excavate a deeper hole than a conventional excavator having a similar structure composed of a base structure such as 10, a boom such as 11, an arm such as 14, and a clamsheIl bucket such as 30 which, however, is suspended from the tip end of the arm by a simple suspension ; means, wherein all these structural members have similar dimensions to those of the excavator of the present invention. In this case, it is important that the parts of the first ropes 98a and 98b and of the second rope 99 which are extended between the clamshell bucket and the first and third pulleys, respectively, are increased ~, .
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or reduced substantially in coincidence with each other due to change of inclination of the boom 11. This is ensured by the structure that the pulleys 63a, 63b, and 63c are coaxial with each other, and the ropes 98a, 98b, and 99 are extended through subst-antially the same paths along the arm and the boom.
Now, the deepest reach of the bucket 30 is obtained when theboom 11 is inclined downwards as much as possible and the arm 14 is positioned perpendicularly with its tip end 14b pointing downward. In this state of the excavator, the actual depth of excavation available is determined by adjusting the length of the ropes 98a, 98b, and 99 so that the length of the parts of these ropes extending between the transverse plate 70b of the frame 70 rotatable around the axis of the arm tip end pulleys 63a, 63b, and 63d and the suspension frame 93 of the bucket 30, or in more detail between the bushes 72 and the rope holding means 97 or between the bush 71 and the bush 94 is as long as desired, provided that dimensions of the base structure 10, the boom 11 and the arm 14 have already been determined. In this case, however, a limit is automatically imposed on the length of these parts, or on the total length of the ropes, from the conditions that the bucket 30, after having scooped a load, must be taken out of the hole vertically, and then must be moved generally sidewards and upwards to reach a transportation means such as a dump truck. In other words, the length of the parts of the ropes extending between the frame 70 and the bucket 30, or the total length of the ropes, must be short enough to ensure the bucket being lifted out of the hole, when the arm 14 is pointing downwards and the boom ll has been raised up as high as possible by operation of the cylinder-piston actuator 12.
In this connection, however, a further limit is imposed on the lengths of the ropes from the condition that, since the ropes extending between the frame 70 and the bucket 30 are further wound up over the arm tip end pulleys 63a, 63b, and 63d, as the arm 14 is then raised up, in order to move the bucket 30 from the position 35 where it has just been taken out from the hole to the position where it has been located on a transportation means, at least this : . .; : :
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. .
.
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winding up clearance must be left as the length of the ropes which extends between the frame 70 and the bucket 30 when the bucket 30 is located at a position where it has just been taken out from the hole, otherwise the bucket 30 would interfere with the frame 70 during further lifting of the bucket towards the next transportation means, thereby obstructing said further lifting of the bucket.
The abovementioned further winding up of the ropes in the process of transferring the bucket from the outlet of the hole to the transportation means is mostly due to the structure that the rotary axis of the pulleys 76a, 76b, and 76c supported by the arm 14 is relatively distant from the axis at 13 of the pivoting of the arm 14 relative to the boom 11, and that the ropes are extended from the tip end of the arm 14 towards the bucket 30 over the outside peripheral portions, as seen from the side of the boom 11, of the pulleys 63a, 63b, and 63d rotatably supported at the tip end of the arm.
These problems are obviated in the excavator shown in Figs.
8 - 12, which is a second embodiment of the present invention. In this second embodiment, pulleys 176a, 176b, and 176c, which have their rotary axes aligned with the second axis at 13 of pivoting the arm 14 relative to the boom 11, are provided to replace the pulleys 76a - 76c in the first embodiment shown in Figs. 1 - 7.
In this connection, as will be better understood from Fig. 11, a pulley 179 is additionally provided to co-operate with the pulley 176b for the convenience of the mechanical structure at the pivoting portion between the boom 11 and the arm 14. By this arrangement, the length of the parts of the ropes extended between the pulleys 91b, 91d, and 91f supported at a middle portion of the boom 11 and the pulleys 63a, 63~, and 63d supported at the tip end of the arm 14 is maintained substantially constant regardless of pivoting action of the arm 14 relative to the boom 11. Further, in the second embodiment shown in Figs. 8 - 12, the ropes 98a, 98b, and 99 are extended from the tip end of the arm 14 towards the bucket 30 over the inside peripheral portions, as seen from ,, .
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the side of the boom 11, of the pulleys 63a, 63b, and 63d, by co-operation of pulleys 153a, 153b, and 153e, some of which replace the pulleys 53a - 53c, while the others are newly provided. By this arrangement, as the arm 14 is raised up in the process of further lifting the bucket 30 from the outside of the hole towards the next transportation means like a dump truck, the ropes are unwound from the pulleys 63a, 63b, and 63d so as to feed the ropes to their parts extended between the frame 70 and the bucket 30.
Thus, in the second embodiment shown in Figs. 8 - 12, the minimum length required for the parts of the ropes extended between the frame 70 and the bucket 30 when the bucket has just been taken out of the hole is reduced. This means that the height of the tip end of the arm 14 from the level at the outlet of the hole at the moment when the bucket 30 is just taken out of the hole can be correspondingly reduced, and that, therefore, the length of the arm can be correspondingly increased, whereby the reach of the tip of the arm can be also correspondingly increased.
In Figs. 8 - 12, which correspond to Figs. 1, 3, 4, 6, and 7, ; respectively, the portions in the second embodiment corresponding to those in the first embodiment are designated by the same reference numerals as in the figures showing the first embodiment.
In this connection, particularly referring to Figs. 9 and 11, 178 is a shaft which rotatably supports the pulley 179 and is in turn supported at its opposite ends by a pair of side plates 177b which extend at right angles from a base plate 177a mounted to the boom 11 adjacent to its tip end.
With respect to the basic structure and function explained with reference to the first embodiment shown in Figs. 1 - 7, it will be obvious that the second embodiment shown in Figs. 8 - 12 has the same basic structure and operates in the same manner as the first embodiment.
.,,, . - - ~,: : , :
`: ~ :' The embodiments of the presen-t invention shown above have comprised a pulley sheave system fixed between the boom and the base structure with both of its mounting points remote from the first axis, and by this arrangement, when the boom is rotated relative to the base structure and the distance between these mounting points changes, the pulley sheave system has amplified this change of distance, so that the change of distance be-tween the clamshell bucket and the tip of the arm has been large, and accordingly the maximum depth of the hole which can be dug has been increased. However, it should be noted that this effect of distance amplification is not strictly necessary for the operation of the present invention, although it is beneficial. It would be possible to provide the first and second ropes, after they have passed over the pulleys attached to the boom, as directly connected to the base structure without being passed over any other pulleys.
In this case there would be no effect of amplification of the change of distance between this fastening point and the boom-mounted pulleys, but this change of distance would be directly applied to the parts of the ropes between the tip of the arm and the bucket. Also, it would be possible to provide the first and second ropes, after they have passed over the pulleys attached to the boom, as passing over pulleys attached to the base structure at a point remote from the first axis, and then as fixed to a point on the boom remote from the first axis. In this case there would be an effect of amplification of the change of distance between these two points by a factor of two only. All of these described possibilities, as well as the two embodiments described in detail above, embody the principle of the present invention:
that change of distance between a point on the base structure and a point on the boom, as the boom is inclined relative to the base structure, is applied to the span of ropes betwen the tip of the arm and the bucket, in order to increase the effective stroke of the bucket.
Although the invention has been shown and described with reference to a preferred embodiment thereof, it should be understood that various changes and omissions of the form and detail thereof may be made by one skilled in the art, without departing from the scope of the invention.
:
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-Fig. 5 is a view similar to a part of Fig. 3, showing a modificatlon of the structure shown in Fig. 3;
30Fig. 6 is a view which shows the entire pulley and rope system of the excavator shown in Fig. 1, in development;
Fig. 7 is a diagrammatical perspective view showing the entire pulley and rope system of the excavator shown in Fig.
1;
Fig. 8 is a view similar to Fig. 1, showing another embodiment .
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, , ~ Z~07~i of the excavator according to the present invention;
Fig. 9 is a somewhat enlarged side view of the arm portion of the excavator shown in Fig. 8;
Fig. 10 is a front view of the arm portion shown in Fig. 9, as viewed along an arrow X;
Fig. 11 is a view which shows the entire pulley and rope system of the excavator shown in Fig. 8, in development;
and -J Fig. 12 is a diagrammatical perspective view showing the entire pulley and rope system of the excavator shown in 15 Fig 8.
DESCRIPTION OF THE PREFERRED E~sODIMENTS
Referring first to Figs. 1 and 2 for the general structure 20 of the excavator according to the present invention, this excavator comprises a base structure 10, which, in this embodiment, is a vehicle body equipped with caterpillar tracks. A boom 11, which in this embodiment has a slightly bent shape, and which has a lower end lla and an upper end 25 llb, is pivotally supported at the lower end lla by the base structure 10, via a pivot shaft 10a, around a first axis.
The boom 11 is rotated around the pivot shaft 10a relative to the base structure 10 by a hydraulic cylinder-piston actuator 12 mounted between the base structure 10 and the 30 boom 11 by pivot shafts 12a and 12b. At the upper end llb of the boom 11 is pivotally supported the root end 14a of an arm 14, via a pivot shaft 13, about a second axis. The arm 14 is rotated around the pivot shaft 13 relative to the boom 11 by a hydraulic cylinder-piston actuator 15, which is mounted between the boom 11 and the very extremity of the root end 14a of the arm 14 by pivot shafts 15a and 16. The arm 14 has a tip end 14b, from which a clamshell bucket 30 .
, .-is suspended as explained in detail hereinunder.
Turning now to Figs. 3 and 4, together with Figs. 1 and2, a pulley and rope system incorporated in the arm portion of the excavator will be explained. 40 designates generally a means for opening and closing the clamshell bucket 30.
This means includes a hydraulic cylinder-piston actuator 20, which has a fixed end 20a which is pivotally mounted to the arm 14 by a pivot means 16a, and a movable end 20b connected with an oblique block 41 by way of a fitting 49. The oblique block 41 has a base plate 41a, and opposite side plates 41b, 41b between which are rotatably mounted three obliquely aligned pulleys 48a, 48b, and 48c properly spaced from each other by a shaft 47 supported by said side plates at opposite ends thereof and spacer means not shown in the figure.
On the upper surface of the arm 14 and adjacent to its tip end 14b is mounted a straight pulley block 51 by its bottom plate 51a, from which are supported a pair of side plates 51b, 51b, between which are rotatably mounted three straight-aligned pulleys 53a, 53b and 53c properly spaced from each other by a shaft 52 supported by said side plates at opposite ends thereof and by spacers. The obliquely aligned pulleys 48a, etc. and the straight-aligned pulleys 53a, etc. form mutually co-operating pulley systems, wherein these pulleys are so arranged that the peripheral portions closest to the viewer, as seen in Fig. 4, of the grooves of the pulleys 48a - 48c are in alignment with the peripheral portions closest to the viewer, as seen in Fig. 4, of the grooves of the pulleys 53a - 53c, respectively, while the peripheral portions furthest from the viewer, as seen in Fig~ 4, of the grooves of the pulleys 48a and 48b are in alignment with the peripheral portions furthest from the viewer, as seen in Fig. 4, of the grooves of the pulleys 53b and 53c, respectively.
From the tip end 14b of the arm 14 are extended a pair of side plates 54, 54 in parallel to each other, by which are supported shafts 61 and 62. At the outside and the inside :
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of the side plates 54, 54 are provided pulleys 63a, 63b, 63c, and 63d rotatably supported by the shaft 61 and properly spaced from each other by proper spacing means. In tnis case, the pulley 63b i5 in alignment with the pulley 53a, while the pulley 63c is in alignment with the peripheral portion furthest from the viewer, as seen in Fig. 4, of the groove of the pulley 48c. In alignment with the pulleys 63a, 63b and 63d are provided three pulleys 65a, 65b, and 65c rotatably supported by the shaft 62 and properly spaced from each other by proper spacing means.
~ A rope guide frame 70 having a pair of side plates 70a, 70a and a trans~erse plate 70b is connected to the shaft 61 so as to be rotatable therearound by the side plates 70a being pivotally mounted to the shaft 61. The transverse plate 70b of the rope guide frame has an opening defined by a bush 71 which is in alignment with the pulley 63b, and two other openings defined by bushes 72, 72 which are in alignment with the pulleys 63a and 63d, respectively.
As a modification of these structures, as shown in Fig.
5, a common bracket 68 which supports the shafts 52, 61 and 62 all together may be provided, so that the common bracket is mounted to the tip end 14b by fittings 18a and l9a.
Returning again to Fig. 3 and further referring to Fig.
6, on the lower face of the arm 14 between the second axis at 13 and the tip end 14b of tne arm is mounted a frame 74 with its bottom plate 74a, from which a pair of side plates 74b, 74b are extended. A shaft 75 is supported by the side plates 74b, 74b at its opposite ends, and three pulleys 76a, 76b, and 76c are rotatably mounted on the shaft 75 and are properly spaced from each other by spacing means~ In this case, as shown in Fig. 6, the pulleys 76a, 76b, and 76c are aligned with the pulleys 63a, 63c, and 63d, respectively.
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Referring to Figs. 1 and 6, a bucket stroke-magnifying mechanism generally designated by 80 is a plurality of sheave systems, and comprises a pair of frames 81 each supporting a pivot pin 82, a frame 83 includiny a bottom plate 83a and side plates 83b, a shaft 8~ supported by the side plates 83b, pulleys 85a, 85b, 85c, 85d, 85e, and 85f rotatably supported by the shaft 84 and properly spaced from each other, a pair of frames 86 each supporting a pivot pin 87, a link element 88 pivotally connecting the frame 83 to the base structure 10 by way of the pivot pins 82 and 87, a frame 89 having a bottom plate 89a and side plates 89b extending at right angles from the base plate 89a and mounted to a middle portion of the boom 11, a shaft 90 supported by the side plates 89b, pulleys 91a, 91b, 91c, 91d, 91e, and 91f rotatably supported by the shaft 90 and spaced properly from each other by spacing means, and ropes 98a, 98b, and 99 engaged with these pulleys. In this case, the pulleys 85a -85f are arranged obliquely, so that the peripheral portion of the groove furthest from the viewer of the pulley 85a and the peripheral portion of the groove closest to the viewer of the pulley 85b, each as seen in Fig. 6 (and similarly hereinunder), are in alignment with the groove of the pulley 91a, the peripheral portion furthest from the viewer of the groove of the pulley 85b is in alignment with the groove of the pulley 91b, the peripheral portion furthest from the v.iewer of the groove of the pulley 85c and the peripheral portion closest to the viewer of the groove of the pulley 85d are in alignment with the groove of the pulley 91c, the peripheral portion furthest from the viewer of 'he groove of the pulley 85d is in alignment with the groove of the pulley 91d, the peri.pheral portion furthest from the viewer of the groove of the pulley 85e and the peripheral portion closest to the viewer of the groove of the pulley 85f are in alignment with the groove of the pulley 91e, and the peripheral portion furthest from the viewer of the groove of the pulley 85f is in alignment with the groove of the pulley 91f. The wire ., . :. ~:
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:
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98a is connected at its one end to the frame 89 at its wire holding element 89c and is extended over the pulleys 85a, 91a,- 85b, 91b, 76a, 65a, and 63a, is passed through the bush 72, and is connected at the other end thereof to a wire holding element 97 of the suspension frame 93 of the clamshell bucket 30. Similarly, the wire 98b is connected at its one end to the wire holding element 89c of the frame 89, is extended over the pulleys 85e, 91e, 85f, 91f, 76c, 65c, and 63d, is passed through the other bush 72, and is connected at its other end to the wire holding element 97 of the suspension frame 93 of the clamshell bucket 30. The wire 99 is connected at its one end to the wire holding element 89c of the frame 89, is extended over the pulleys 85c, 91c, 85d, 91d, 76b, 63c, 48c, 53c, 48b, 53b, 48a, 53a, 65b, and 63b, is passed through the bush 71, and is connected at its other end to the shell opening and closing mechanism 95 of the clamshell bucket 30. In this case, in more detail, the end portion of the rope 99 is passed through an opening defined by a bush 94 in the suspension frame 93 of the clamshell bucket 30, is extended over several pulleys of the shell opening and closing mechanism 95, and is connected to the rope holding element 96 of the suspension frame 93. A rope operated clamshell bucket such as the bucket 30 is itself well known in the art, and operates in such a manner that, when the rope 99 is pulled out from the shell opening and closing mechanism 95, the clamshell is closed, and when the rope 99 is fed to the shell opening and closing mechanism, the clamshell opens.
The abovementioned arrangement of the ropes 98a, 98b, and 99 is shown in ~ig. 7 in a diagrammatical perspective view. By this arrangement of pulleys and ropes, when the clamshell bucket 30 is opened by the rope 99 being loosened by expansion of the hydraulic cylinder piston actuator 20, the clamshell bucket 30 is suspended substantially by the pair of ropes 98a and 98b, and, when the clamshell bucket 30 ,: ~ ; ~, ~, .. ' .Zi~3~7~i is closed by the rope 99 being tightened by contraction of the actuator 20, the clamshell bucket 30 and generally the load supported by the bucket are suspended by the rope 99, while the pair of ropes 98a and 98b are maintained in a slightly loosened condition so that full closing of the bucket is ensured.
In operation, when the boom 11 is gradually more inclined from a position such as shown in Fig. 1, so as to lower the bucket 30 to the bottom of a hole which is being excavated, the distance between the pulleys 85a - 85f arld the pulleys 91a - 91f is gradually shortened, whereby more of the ropes 98a, 98b, and 99 is fed to the span portions of these ropes which extend between the tip of the arm 14 and the clamshell bucket 30, thereby increasing the depth of the hole whose bottom can be reached by the clamshell bucket, as compared with a conventional excavator having comparable dimensions with regard to the base structure 10, the boom 11, and the arm 14, under the condition that the bucket which is excavating the bottom of the hole must of course be taken out of the hole to dump the excavated matter onto a proper transportation means such as a dump truck or the like.
In other words, in the excavator according to the present invention, if the relative position between the boom 11 and the axm 14 is maintained constant, when the boom ll is rotated around the first axis about the pivot shaft lOa by means of the cylinder-piston actuator 12, the bucket 30 mo~es up and down for more than the up and down shift traversed by the tip end of the arm 14.
Thus the excavator of the present invention can excavate a deeper hole than a conventional excavator having a similar structure composed of a base structure such as 10, a boom such as 11, an arm such as 14, and a clamsheIl bucket such as 30 which, however, is suspended from the tip end of the arm by a simple suspension ; means, wherein all these structural members have similar dimensions to those of the excavator of the present invention. In this case, it is important that the parts of the first ropes 98a and 98b and of the second rope 99 which are extended between the clamshell bucket and the first and third pulleys, respectively, are increased ~, .
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or reduced substantially in coincidence with each other due to change of inclination of the boom 11. This is ensured by the structure that the pulleys 63a, 63b, and 63c are coaxial with each other, and the ropes 98a, 98b, and 99 are extended through subst-antially the same paths along the arm and the boom.
Now, the deepest reach of the bucket 30 is obtained when theboom 11 is inclined downwards as much as possible and the arm 14 is positioned perpendicularly with its tip end 14b pointing downward. In this state of the excavator, the actual depth of excavation available is determined by adjusting the length of the ropes 98a, 98b, and 99 so that the length of the parts of these ropes extending between the transverse plate 70b of the frame 70 rotatable around the axis of the arm tip end pulleys 63a, 63b, and 63d and the suspension frame 93 of the bucket 30, or in more detail between the bushes 72 and the rope holding means 97 or between the bush 71 and the bush 94 is as long as desired, provided that dimensions of the base structure 10, the boom 11 and the arm 14 have already been determined. In this case, however, a limit is automatically imposed on the length of these parts, or on the total length of the ropes, from the conditions that the bucket 30, after having scooped a load, must be taken out of the hole vertically, and then must be moved generally sidewards and upwards to reach a transportation means such as a dump truck. In other words, the length of the parts of the ropes extending between the frame 70 and the bucket 30, or the total length of the ropes, must be short enough to ensure the bucket being lifted out of the hole, when the arm 14 is pointing downwards and the boom ll has been raised up as high as possible by operation of the cylinder-piston actuator 12.
In this connection, however, a further limit is imposed on the lengths of the ropes from the condition that, since the ropes extending between the frame 70 and the bucket 30 are further wound up over the arm tip end pulleys 63a, 63b, and 63d, as the arm 14 is then raised up, in order to move the bucket 30 from the position 35 where it has just been taken out from the hole to the position where it has been located on a transportation means, at least this : . .; : :
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.
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winding up clearance must be left as the length of the ropes which extends between the frame 70 and the bucket 30 when the bucket 30 is located at a position where it has just been taken out from the hole, otherwise the bucket 30 would interfere with the frame 70 during further lifting of the bucket towards the next transportation means, thereby obstructing said further lifting of the bucket.
The abovementioned further winding up of the ropes in the process of transferring the bucket from the outlet of the hole to the transportation means is mostly due to the structure that the rotary axis of the pulleys 76a, 76b, and 76c supported by the arm 14 is relatively distant from the axis at 13 of the pivoting of the arm 14 relative to the boom 11, and that the ropes are extended from the tip end of the arm 14 towards the bucket 30 over the outside peripheral portions, as seen from the side of the boom 11, of the pulleys 63a, 63b, and 63d rotatably supported at the tip end of the arm.
These problems are obviated in the excavator shown in Figs.
8 - 12, which is a second embodiment of the present invention. In this second embodiment, pulleys 176a, 176b, and 176c, which have their rotary axes aligned with the second axis at 13 of pivoting the arm 14 relative to the boom 11, are provided to replace the pulleys 76a - 76c in the first embodiment shown in Figs. 1 - 7.
In this connection, as will be better understood from Fig. 11, a pulley 179 is additionally provided to co-operate with the pulley 176b for the convenience of the mechanical structure at the pivoting portion between the boom 11 and the arm 14. By this arrangement, the length of the parts of the ropes extended between the pulleys 91b, 91d, and 91f supported at a middle portion of the boom 11 and the pulleys 63a, 63~, and 63d supported at the tip end of the arm 14 is maintained substantially constant regardless of pivoting action of the arm 14 relative to the boom 11. Further, in the second embodiment shown in Figs. 8 - 12, the ropes 98a, 98b, and 99 are extended from the tip end of the arm 14 towards the bucket 30 over the inside peripheral portions, as seen from ,, .
, 37~
the side of the boom 11, of the pulleys 63a, 63b, and 63d, by co-operation of pulleys 153a, 153b, and 153e, some of which replace the pulleys 53a - 53c, while the others are newly provided. By this arrangement, as the arm 14 is raised up in the process of further lifting the bucket 30 from the outside of the hole towards the next transportation means like a dump truck, the ropes are unwound from the pulleys 63a, 63b, and 63d so as to feed the ropes to their parts extended between the frame 70 and the bucket 30.
Thus, in the second embodiment shown in Figs. 8 - 12, the minimum length required for the parts of the ropes extended between the frame 70 and the bucket 30 when the bucket has just been taken out of the hole is reduced. This means that the height of the tip end of the arm 14 from the level at the outlet of the hole at the moment when the bucket 30 is just taken out of the hole can be correspondingly reduced, and that, therefore, the length of the arm can be correspondingly increased, whereby the reach of the tip of the arm can be also correspondingly increased.
In Figs. 8 - 12, which correspond to Figs. 1, 3, 4, 6, and 7, ; respectively, the portions in the second embodiment corresponding to those in the first embodiment are designated by the same reference numerals as in the figures showing the first embodiment.
In this connection, particularly referring to Figs. 9 and 11, 178 is a shaft which rotatably supports the pulley 179 and is in turn supported at its opposite ends by a pair of side plates 177b which extend at right angles from a base plate 177a mounted to the boom 11 adjacent to its tip end.
With respect to the basic structure and function explained with reference to the first embodiment shown in Figs. 1 - 7, it will be obvious that the second embodiment shown in Figs. 8 - 12 has the same basic structure and operates in the same manner as the first embodiment.
.,,, . - - ~,: : , :
`: ~ :' The embodiments of the presen-t invention shown above have comprised a pulley sheave system fixed between the boom and the base structure with both of its mounting points remote from the first axis, and by this arrangement, when the boom is rotated relative to the base structure and the distance between these mounting points changes, the pulley sheave system has amplified this change of distance, so that the change of distance be-tween the clamshell bucket and the tip of the arm has been large, and accordingly the maximum depth of the hole which can be dug has been increased. However, it should be noted that this effect of distance amplification is not strictly necessary for the operation of the present invention, although it is beneficial. It would be possible to provide the first and second ropes, after they have passed over the pulleys attached to the boom, as directly connected to the base structure without being passed over any other pulleys.
In this case there would be no effect of amplification of the change of distance between this fastening point and the boom-mounted pulleys, but this change of distance would be directly applied to the parts of the ropes between the tip of the arm and the bucket. Also, it would be possible to provide the first and second ropes, after they have passed over the pulleys attached to the boom, as passing over pulleys attached to the base structure at a point remote from the first axis, and then as fixed to a point on the boom remote from the first axis. In this case there would be an effect of amplification of the change of distance between these two points by a factor of two only. All of these described possibilities, as well as the two embodiments described in detail above, embody the principle of the present invention:
that change of distance between a point on the base structure and a point on the boom, as the boom is inclined relative to the base structure, is applied to the span of ropes betwen the tip of the arm and the bucket, in order to increase the effective stroke of the bucket.
Although the invention has been shown and described with reference to a preferred embodiment thereof, it should be understood that various changes and omissions of the form and detail thereof may be made by one skilled in the art, without departing from the scope of the invention.
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Claims (15)
1. An excavator comprising:
a base structure;
a boom having a lower and an upper end and pivotally supported around a first axis at its lower end by the base structure and inclining in a certain direction;
a means for turning the boom around the first axis with respect to the base structure;
an arm having a root and a tip end and pivotally supported around a second axis near its root end by the upper end of the boom;
a means for turning the arm around the second axis with respect to the boom;
a clamshell bucket having a suspension frame and a rope-operated shell opening and closing mechanism;
a first pulley and rope system including:
a first pulley mounted rotatably at the tip end of the arm;
a second pulley mounted rotatably on the boom at a position substantially distant from the first axis, and a first rope, which is connected at one of its ends to the suspension frame of the clamshell bucket, and which is extended over, in order from this end, the first and second pulleys, and which then exerts force against the base structure at a base bearing point substantially distant from the first axis -------------------------------------------------------and spaced therefrom in the direction of inclination of the boom, the force of its tension being supported by the base structure at this base bearing point, and which is fixedly connected at its other end to only one of said base structure and said boom;
and a second pulley and rope system including:
a third pulley mounted rotatably at the top end of the arm substantially coaxially with the first pulley, a cylinder-piston actuator having a fixed and a movable end and supported at the fixed end by the arm, a fourth pulley mounted rotatably at the movable end of the acutator, a fifth pulley supported by the arm, a sixth pulley supported by the boom substantially coaxially with the second pulley, and a second rope, which acts. near one of its ends on the shell opening and closing mechanism so as to operate it, and which is extended over, in order from this end, the third, fourth, fifth, and sixth pulleys, and which then exerts force against the base structure at a point substantially the same as the base bearing point, and which is fixedly connected at its other end to only one of said base structure and said boom.
a base structure;
a boom having a lower and an upper end and pivotally supported around a first axis at its lower end by the base structure and inclining in a certain direction;
a means for turning the boom around the first axis with respect to the base structure;
an arm having a root and a tip end and pivotally supported around a second axis near its root end by the upper end of the boom;
a means for turning the arm around the second axis with respect to the boom;
a clamshell bucket having a suspension frame and a rope-operated shell opening and closing mechanism;
a first pulley and rope system including:
a first pulley mounted rotatably at the tip end of the arm;
a second pulley mounted rotatably on the boom at a position substantially distant from the first axis, and a first rope, which is connected at one of its ends to the suspension frame of the clamshell bucket, and which is extended over, in order from this end, the first and second pulleys, and which then exerts force against the base structure at a base bearing point substantially distant from the first axis -------------------------------------------------------and spaced therefrom in the direction of inclination of the boom, the force of its tension being supported by the base structure at this base bearing point, and which is fixedly connected at its other end to only one of said base structure and said boom;
and a second pulley and rope system including:
a third pulley mounted rotatably at the top end of the arm substantially coaxially with the first pulley, a cylinder-piston actuator having a fixed and a movable end and supported at the fixed end by the arm, a fourth pulley mounted rotatably at the movable end of the acutator, a fifth pulley supported by the arm, a sixth pulley supported by the boom substantially coaxially with the second pulley, and a second rope, which acts. near one of its ends on the shell opening and closing mechanism so as to operate it, and which is extended over, in order from this end, the third, fourth, fifth, and sixth pulleys, and which then exerts force against the base structure at a point substantially the same as the base bearing point, and which is fixedly connected at its other end to only one of said base structure and said boom.
2. An excavator as in claim 1, wherein the first and second pulley and rope systems further comprise first and second auxiliary pulleys which are rotatably fixed so as to exert force against the base bearing point, and wherein the first and second ropes are passed, in their directions leading away from the clamshell bucket, and having passed over the second and the sixth pulleys respectively, over the first and second auxiliary pulleys, and are then attached at their said other ends to the boom at substantially the same point as one another, said point being substantially remote from the first axis, without being passed over any other pulleys.
3. An excavator as in claim 1, wherein the first and second pulley and rope systems further comprise first and second sheave systems, respectively, extended between the base bearing point and a point on the boom substantially remote from the first axis, and wherein the first and second ropes are conducted through the first and second sheave systems in their parts between the second and the sixth pulleys and their said other ends, respectively.
4. An excavator as in claim 3, wherein the said other ends of the first and second ropes are secured to the boom.
5. An excavator as in claim 1, wherein the said other ends of the first and second ropes are secured to the base structure.
6. An excavator as in claim 5, wherein the first and second ropes, after they have passed over the second and the sixth pulleys respectively, are directly attached to the base structure.
7. An excavator as in claim 3, wherein the second and sixth pulleys are integrated in the first and second sheave systems, respectively.
8. An excavator as in claim 3, wherein the first and second sheave systems are integrally combined.
9. An excavator as in claim 1, wherein the second pulley and rope system comprises an actuator sheave system which includes the fourth pulley and is extended between the tip end of the arm and the movable end of the actuator, and wherein the second rope is conducted through an actuator sheave system in its part between the third and fifth pulleys.
10. An excavator as in claim 1, wherein the first and second pulley and rope systems further comprise seventh and eighth pulleys, respectively, rotatably supported by the arm, and wherein the first rope is extended over the seventh pulley in its part between the first and second pulleys, while the second rope is extended over the eighth pulley in its part between the fifth and sixth pulleys.
11. An excavator as in claim 10, wherein the seventh and the eighth pulleys are rotatable around the second axis.
12. An excavator as in claim 1, wherein the first and second pulley and rope systems further comprise first and second supplementary supported by the arm so as to be positioned between the first and second pulleys and between the third and fourth pulleys as viewed along the first and second ropes, respectively, and wherein the first and second ropes are directed from the first and third pulleys towards the suspension frame and the shell opening and closing mechanism of the clamshell bucket around the peripheral portions of the first and third pulleys, respectively, which are closer to the boom.
13. An excavator as in claim 12, wherein the second pulley and rope system comprises an actuator sheave system which includes the fourth pulley and is extended between the tip end of the arm and the movable end of the actuator, and wherein the second rope is conducted through said actuator sheave system in its path between the third and fifth pulleys.
14. An excavator as in claim 1, 2 or 3, wherein the first pulley and rope system is provided in duplicate.
15. An excavator as in claim 1, 2 or 3, further comprising a guide means supported by the tip end of the arm so as to be rotatable around the same axis as the first and third pulleys and having a first guide opening which conducts the first rope therethrough between the first pulley and the suspension frame of the clamshell bucket and a second opening which conducts the second rope therethrough between the third pulley and the shell opening and closing mechanism.
Applications Claiming Priority (4)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP9218078A JPS5519372A (en) | 1978-07-28 | 1978-07-28 | Hydraulic clamshell operation device |
| JPSOWA53-092180(09218 | 1978-07-28 | ||
| JP10451178A JPS5532807A (en) | 1978-08-28 | 1978-08-28 | Rope-operated clam shell bucket functioning device for hydraulic shovel |
| JP53-104511(104511/78) | 1978-08-28 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1120076A true CA1120076A (en) | 1982-03-16 |
Family
ID=26433648
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000330276A Expired CA1120076A (en) | 1978-07-28 | 1979-06-21 | Excavator with a clamshell bucket having magnified vertical stroke |
Country Status (3)
| Country | Link |
|---|---|
| CA (1) | CA1120076A (en) |
| DE (1) | DE2929463C2 (en) |
| FR (1) | FR2432069A1 (en) |
Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR2755709B1 (en) * | 1996-11-14 | 1999-02-05 | Sol Comp Du | DRILLING DEVICE COMPRISING A DRILLING MACHINE |
| CN103485381A (en) * | 2013-09-09 | 2014-01-01 | 浙江鼎业基础工程有限公司 | Percussive grabbing machine |
| IT201900001761A1 (en) | 2019-02-07 | 2019-02-07 | ||
| CN110374155B (en) * | 2019-07-04 | 2021-07-02 | 徐州益康环保科技有限公司 | Environment-friendly dredging equipment for water area |
Family Cites Families (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR1395871A (en) * | 1964-03-07 | 1965-04-16 | Improvements to hydraulically operated cranes | |
| US3396946A (en) * | 1967-01-23 | 1968-08-13 | Garrel O Day | Attachment for a backhoe or other vehicle |
| FR1546537A (en) * | 1967-06-28 | 1968-11-22 | Poclain Sa | Winding device for hoses for supplying pressurized fluid to receivers |
| DE2501780C3 (en) * | 1975-01-17 | 1979-07-12 | Liebherr-Hydraulikbagger Gmbh, 7951 Kirchdorf | Hydraulic excavator |
| DE2550414C3 (en) * | 1975-11-10 | 1978-11-16 | Liebherr-Hydraulikbagger Gmbh, 7951 Kirchdorf | Hydraulic excavator |
-
1979
- 1979-06-21 CA CA000330276A patent/CA1120076A/en not_active Expired
- 1979-06-29 FR FR7916989A patent/FR2432069A1/en active Pending
- 1979-07-20 DE DE19792929463 patent/DE2929463C2/en not_active Expired
Also Published As
| Publication number | Publication date |
|---|---|
| DE2929463C2 (en) | 1982-12-30 |
| DE2929463A1 (en) | 1980-02-07 |
| FR2432069A1 (en) | 1980-02-22 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |