CA2224703A1 - Device for mounting and dismounting counterweight - Google Patents
Device for mounting and dismounting counterweight Download PDFInfo
- Publication number
- CA2224703A1 CA2224703A1 CA002224703A CA2224703A CA2224703A1 CA 2224703 A1 CA2224703 A1 CA 2224703A1 CA 002224703 A CA002224703 A CA 002224703A CA 2224703 A CA2224703 A CA 2224703A CA 2224703 A1 CA2224703 A1 CA 2224703A1
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- Prior art keywords
- counterweight
- boom
- hydraulic cylinder
- cable
- attached
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- 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
- E02F9/18—Counterweights
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- Engineering & Computer Science (AREA)
- Mining & Mineral Resources (AREA)
- Civil Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Structural Engineering (AREA)
- Jib Cranes (AREA)
- Component Parts Of Construction Machinery (AREA)
Abstract
A device which facilitates mounting and dismounting a counterweight and is inexpensive. The device comprises hydraulic cylinders (41, 42) mounted on an upper swivel (23), a first cable (55) connecting tip ends of rods (45, 46) of the hydraulic cylinders (41, 42) to a boom (31), and a second cable (58) connecting the tip ends of the rods (45, 46) of the hydraulic cylinders (41, 42) to a counterweight (28), wherein the counterweight (28) can be hung up and down by expansion and contraction of the hydraulic cylinders (41, 42) and rising and falling of the boom (31).
Description
DESCRIPTION
COUNTERWEIGHT MOUNTING/DISMOUNTING DEVICE
TECHNICAL FIELD
The present invention relates to a counterweight mounting/dismounting device for use in construction vehicles such as hydraulic excavators and cranes.
BACKGROUND ART
A prior art counterweight mounting/dismounting device for hydraulic excavators will be described with reference to Fig. 16. A traveling undercarriage 21 of a hydraulic excavator 20 is able to run back and forth by a travel motor (not shown). An upper revolving turret 23 capable of revolving by a turn motor (not shown) is mounted on the traveling undercarriage 21. The upper revolving turret 23 is provided with a working attachment 30, a machine cab 26, an operator cabin 27 and a counterweight 28a. The working attachment 30 comprises a boom 31, an arm 33, a bucket 35 and a plurality of hydraulic cylinders 32, 34, 36, and is operated to carry out the work of digging earth and sand. The counterweight 28a is fixed onto a rear portion of the upper revolving turret 23 by bolts or the like for balancing against both the working attachment 30 and the working load.
For large-sized hydraulic excavators, however, it is often required to dismount a counterweight and transport the same separately because the excavator weight exceeds the value prescribed by the Road Traffic Act when transported in a full-equipped state. In addition, a crane truck must be prepared to mount and dismount the counterweight and, hence, the expenditure increases. To solve such a problem, there are known techniques wherein a counterweight mounting/-dismounting device is equipped on a hydraulic excavator.
According to Japanese Utility Model Publication No.
5-3568, for example, a cable is extended from a hook provided onxp'theear surface of a boom of a working attachment to a hook on the top of a counterweight through a pulley provided at the upper end of a rear stand on an excavator body. By raising and lowering the boom about its base end, the cable is moved to lift up and down the counterweight. Also, according to Japanese Utility Model Laid-Open No. 59-5669, a cable is extended from a hook provided on the rear surface of a boom of a working attachment to a hook on the top of a counterweight through a pulley provided at the upper end of a link which is turnably attached to a rear stand on an excavator body.
The counterweight is moved forth and back by turning the CA 02224703 1997-12-1~
link with an actuator, and is lifted up and down by raising and lowering the boom about its base end.
Further, according to Japanese Utility Model Laid-Open No. 62-21160, a cable is extended from a hook provided on the rear surface of a boom of a working attachment to a hook on the top of a counterweight through a pulley provided at the upper end of a mast which is turnably attached to a rear portion on an excavator body.
The counterweight is moved forth and back by turning the mast with an actuator, and is lifted up and down by raising and lowering the boom about its base end.
Moreover, according to Japanese Utility Model Laid-Open No. 61-141363, a cable is extended from a hook provided at the upper end of a rear stand on an excavator body to a hook on the top of a counterweight through a pulley provided on the rear surface of a boom of a working attachment, a pulley provided on the stand, and a pulley provided on a link which is turnably attached to the stand. Further, a hook provided at the upper end of the link and a hook provided on an arm of the working attachment are interconnected by a cable. The counterweight is moved forth and back by turning the arm of the working attachment, and is lifted up and down by raising and lowering the boom about its base end.
However, any of the foregoing prior art devices has had the problems of complicated structure, expensive cost and complex mounting/dismounting operation, because of requiring one or more pulleys, a pulley mounting stand, a link unit for changing the pulley position, and so on.
DISCLOSURE OF THE INVENTION
The present invention has been accomplished with a view of the foregoing problems in the prior art, and its object is to provide a counterweight mounting/dismounting device which enables a counterweight to be easily mounted and dismounted, and which is less costly.
With a first aspect of the counterweight mounting/-dismounting device according to the present invention, in a construction vehicle comprising an upper revolving turret, a boom attached to a front portion of the upper revolving turret, and a counterweight detachably mounted on a rear portion of the upper revolving turret, the counterweight mounting/dismounting device comprises a hydraulic cylinder pivotally attached to and support on a frame of the upper revolving turret, a first cable interconnecting the distal end of a rod of the hydraulic cylinder and the boom, and a second cable interconnecting the distal end of the rod and the counterweight, the counterweight being lifted up and down by extending and contracting the hydraulic cylinder and raising and CA 02224703 1997-12-1~
lowering the boom about the boom base end.
The first cable may interconnect a first hook attached to the distal end of the rod and a hook provided on the boom, and the second cable may interconnect a second hook attached to the distal end of the rod and a hook provided on the counterweight. Further, a connecting shaft may be attached to the distal end of the rod, and the first hook, the second hook and the distal end of the rod may be each rotatable about the connecting shaft.
Preferably, the counterweight is formed with a recess in which the hydraulic cylinder can be arranged. Also preferably, the position at which the base end of the hydraulic cylinder is attached to the frame is closer to the boom than a vertical line passing a longitudinal centroid position of the counterweight, and the position at which the first cable is connected to the distal end of the rod is rearer in the longitudinal direction of the vehicle than the attachment position of the base end of the hydraulic cylinder. Further, the hydraulic cylinder may comprise a plurality of hydraulic cylinders, and the plurality of hydraulic cylinders may be attached at their distal ends to the frame and are arranged on both sides of a transverse centroid position of the counterweight.
With a second aspect of the counterweight mounting/-dismounting device according to the present invention, the CA 02224703 1997-12-1~
device comprises a hydraulic cylinder pivotally attached to and supported on a frame of an upper revolving turret, brackets provided on the frame, an outer box pivotally attached to the brackets, an inner box pivotally attached to the distal end of a rod of the hydraulic cylinder and being able to move vertically along inner surfaces of the outer box, a first cable interconnecting the distal end of the rod and the boom, and a second cable interconnecting the distal end of the rod and the counterweight, the counterweight being lifted up and down by extending and contracting the hydraulic cylinder and raising and lowering the boom about the base end.
According to the present invention constituted as set forth above, when dismounting the counterweight, the boom is set to a forward inclined position and the first cable is stretched to interconnect the first hook and the boom hook. Subsequently, the second cable is stretched to interconnect the second hook and the counterweight hook.
Then, for dislodging the counterweight from the upper revolving turret, lock bolts are removed and the hydraulic cylinder is extended to lift up the counterweight. By turning the boom rearward in this condition, the counterweight is separated from the body frame and moved downward. After the boom has been moved to a rearward inclined position, by contracting the hydraulic cylinder, CA 02224703 1997-12-1~
the counterweight is further moved downward so as to rest on the ground.
The operation of mounting the counterweight can be basically performed through steps which are reversal of the foregoing steps. More specifically, the boom is set to the rearward inclined position, the first and second cables are stretched between the hooks, and the hydraulic cylinder is extended to lift up the counterweight. By turning the boom forward in this condition, the counterweight is raised without contacting the body frame.
After the counterweight has been moved to a location just above its mount position, the turning of the boom is stopped and the hydraulic cylinder is contracted, whereby the counterweight is moved downward so as to seat on the body frame. The counterweight is then fixed in place by setting the lock bolts.
Thus, since the counterweight mounting/dismounting device has the simple structure achievable just by preparing the hydraulic cylinder, the hook attached to the distal end of the rod, and the cables for lifting the counterweight up and down, it is possible to easily carry out the operation of mounting/dismounting the counterweight and reduce the cost.
BRIEF DESCRIPTION OF THE DRAWINGS
Fig. 1 is a side view of a counterweight mounting/-dismounting device according to a first embodiment of the present invention, Figs. 2A and 2B are detailed views of the counterweight mounting/dismounting device shown in Fig. 1, in which: Fig. 2A is a side view showing a counterweight and hydraulic cylinders in a mounted state and Fig. 2B is a perspective view of the counterweight, Fig. 3 is a view looking from the direction of arrow III in Fig. 2A, Fig. 4 is a hydraulic circuit diagram of the counterweight mounting/dismounting device according to the first embodiment, Figs. 5 to 8 are views for explaining the operation of the counterweight mounting/dismounting device according to the first embodiment, in which:
Fig. 5 is a first operation explaining view, Fig. 6 is a second operation explaining view, Fig. 7 is a third operation explaining view, and Fig. 8 is a fourth operation explaining view, Fig. 9 is a side view showing the counterweight according to the first embodiment in a state rested on the ground, Fig. 10 is a sectional view of a hydraulic cylinder interconnecting portion of a counterweight mounting/-CA 02224703 1997-12-1~
dismounting device according to a second embodiment of the present invention, Fig. 11 is an explanatory view showing hydraulic cylinders, in a mounted state, of a counterweight mounting/dismounting device according to a third embodiment of the present invention, Fig. 12 is a view looking from the direction of arrow XII in Fig. 12, Fig. 13 is an explanatory view showing hydraulic cylinders, in a mounted state, of a counterweight mounting/dismounting device according to a fourth embodiment of the present invention, Fig. 14 is an explanatory view taken along section XIV - XIV in Fig. 13, Fig. 15 is an enlarged view taken along section XV -XV in Fig. 14, and Fig. 16 is a side view of a prior art hydraulic excavator.
BEST MODE FOR CARRYING OUT THE INVENTION
Preferred embodiments of the present invention will be hereinafter described in detail with reference the attached drawings.
Fig. 1 shows a first embodiment in which a hook 56 is fixed to a boom 31. Hydraulic cylinders 41, 42 are connected to a counterweight 28 through cables 58, 58 (see Fig. 2). A first cable 55 is secured to one end of each of the hydraulic cylinders 41, 42 and the hook 56 through shackles 57, 57.
Referring to Figs. 2A and 2B, the counterweight 28 is detachably mounted by bolts 12 to a body frame 11 arranged inside an upper revolving turret 23. The counterweight 28 has a hanging hook 29 provided on its upper surface and positioned to lie on a vertical line passing the centroid position W. Bottom sides 43, 44 of the hydraulic cylinders 41, 42 are pivotally attached by pins 14 to brackets 13 provided on the body frame 11. The center of each hole to which the pin 14 is fitted is positioned nearer to a front portion of the body than the centroid position W of the counterweight 28 by a distance L when the counterweight 28 is in a mounted state. A recess 28b is formed in a central portion of the counterweight 28 to provide a space enough to arrange the two hydraulic cylinders 41, 42 therein.
Referring to Fig. 3, rods 45, 46 of the hydraulic cylinders 41, 42 are fixed by using stoppers 48 to a shaft (connecting shaft) 47 having female threads formed at both ends thereof. A first hook 51 (see Fig. 2A) for the first cable 55 and second hooks 52 for the second cables 58 are rotatably fitted over a central portion and both end CA 02224703 1997-12-1~
portions of the shaft 47, respectively. Each of the second cables 58 has one end connected to the hook 29 provided on the counterweight 28 through a shackle 59, and the other end connected to the second hook 52 through a shackle 59.
Fig. 4 shows a hydraulic circuit for operating the hydraulic cylinders 41, 42. A hydraulic pump 61 for driving the hydraulic cylinders 32, 34, 36 of the working attachment 30 is also employed as a hydraulic source. A
rotary valve 64 is provided to switch over the supply of pressure oil between a first main valve 62 through which the pressure oil is supplied to the hydraulic cylinders 32, 34, 36 and a second main valve 63 for operating the counterweight 28. A counterbalance valve 65 is disposed between the second main valve 63 and the hydraulic cylinders 41, 42.
The operation of dismounting the counterweight with the above-described construction will now be described below. When the counterweight 28 is kept mounted on the body frame 11 as shown in Figs. 1 to 3 and 5, the rods 45, 46 of the hydraulic cylinders 41, 42 are in a contracted state. In this condition, the first cable 55 is stretched between the hook 56 of the boom 31 and the first hook 51 for the hydraulic cylinders 41, 42 through the shackles 57. Then, the two cables 58 are stretched between the hook 29 of the counterweight 28 and the second hook 52 for the hydraulic cylinders 41, 42 through the shackles 59.
Next, the boom 31 iS turned forward to bring the first cable 55 into a state where it is slightly tensioned. The positions of the boom 31, the hydraulic cylinders 41, 42 and the counterweight 28 at this time are assumed to be initial positions, as shown in Fig. 5. The whole of an excavator under this condition is shown in Fig. 1. Subsequently, the bolts 12 for locking the counterweight 28 in the mounted state are removed. Then, after switching over the rotary valve 64 shown in Fig. 4 so as to supply the pressure oil to the second main valve 63 side, the second main valve 63 iS shifted to an "extension" position indicated in Fig. 4. Upon this shift of the second main valve 63, as shown in Fig. 6, the rods 45, 46 of the hydraulic cylinders 41, 42 are extended to exert a tension on the second cables 58, causing the counterweight 28 to start floating. When the rods 45, 46 are further extended, the tip ends of the rods 45, 46 reach a maximum length in a position Q and, at the same time, the counterweight 28 iS lifted upward and moved to a position A.
Next, after switching over the rotary valve 64 SO as to supply the pressure oil to the first main valve 62 side, the boom 31 iS turned rearward as shown in Fig. 7, whereupon the counterweight 28 is separated from the frame 11 and moved downward. By further turning the boom 31 rearward, the boom 31 reaches a fully rearward inclined position, the rods 45, 46 take a position R, and the counterweight 28 moves to a position B. In this condition, the rotary valve 64 is switched over so as to supply the pressure oil to the second main valve 63 side, the second main valve 63 is shifted to a "contraction"
position (see Fig. 4), and the rods 45, 46 are contracted as shown in Fig. 8. As a result, the rods 45, 46 take a position S and the counterweight 28 is moved downward to a position D where it rests on the ground. Since the counterbalance valve 65 is operated in the course of the above downward movement of the counterweight 28, it is possible to prevent the counterweight 28 from dropping by its own weight. The whole of an excavator under this condition is shown in Fig. 9.
After the counterweight 28 has been rested on the ground, the two second cables 58 are removed with the rods 45, 46 held in their shortest positions. Then, the boom 31 is turned forward and, when the rods 45, 46 are moved to a position P shown in Fig. 5, the hydraulic cylinders 41, 42 are secured to the frame 11 by respective fixtures (not shown). The operation of dismounting the counterweight 28 is then completed by removing the first CA 02224703 l997-l2-l~
cable 55. While the operation of dismounting the counterweight 28 has been described above, the operation of mounting the counterweight 28 can be performed through steps which are reversal of the foregoing steps.
With the first embodiment described above, the two hydraulic cylinders 41, 42 are connected together by the shaft 47 with the first hook 51 held therebetween and the second hooks 52 are provided at both ends of the shaft 47.
Further, the hook 5 6 of the boom 31 and the first hook 51 in the cylinder connecting portion are interconnected by the first cable 55, and the hook 29 of the counterweight 28 and the second hooks 52 in the cylinder connecting portion are interconnected by the two second cables 58.
Therefore, the counterweight 28 can be easily mounted and dismounted by extending and contracting the hydraulic cylinders 41, 42 and raising and lowering the boom 31 about its base end. Also, since the second cables 58 have a sufficient length, the counterweight 28 can be easily positioned for alignment when the second cables 28 are attached to the counterweight 28 for mounting it. In addition, since the hydraulic cylinders 41, 42 each have a sufficient stroke, the counterweight 28 can be moved downward so that it completely rests on the ground.
The first hook 51 and the two second hooks 52 are freely rotatably about the shaft 47, and the forces exerted from the first cable 55 and the second cables 58 are transmitted through the center of the shaft 47.
Therefore, the hydraulic cylinders 41, 42 are subjected to no bending load, which makes it possible to smoothly operate the hydraulic cylinders 41, 42 and reduce the size thereof. Also, since the mounting/dismounting device comprises only the two hydraulic cylinders 41, 42, the portion for connecting the hydraulic cylinders 41, 42 together, and the cables 55, 58, 58, conventionally employed members such as a stand, a pulley and a link are no longer required, which results in the simplified structure and the reduced cost in addition to the above size reduction.
Other embodiments of the device for mounting/-dismounting the counterweight 28 will be described below.
Fig. 10 shows an essential part of a second embodiment. The rods 45, 46 of the hydraulic cylinders 41, 42 are fixed to a shaft 47a, which has female threads formed at both ends thereof, by second seated hooks 52a for the second cables 58. The first hook 51 for the first cable 55 is rotatably fitted over a central portion of the shaft 47a, and the shaft 47a is rotatable about the centers of holes formed in the rods 45, 46 for insertion of the shaft 47a. With such a construction, the structure is simplified and the cost is further reduced.
CA 02224703 1997-12-1~
Figs. 11 and 12 show a third embodiment. Spherical bearings 49, 49 are fitted respectively over bottom ends 43a, 44a of the hydraulic cylinders 41a, 42a and attached through pins 14a to brackets 13a provided on the frame 11.
Spherical bearings 49, 49 are fitted respectively over rods 45a, 46a of the hydraulic cylinders 41a, 42a. A
first hook 51a for the first cable 55 is held at the middle between the spherical bearings 49, 49, and inner cylinders 49a, 49a of the spherical bearings 49, 49 are fixed to a shaft 47b, which has female threads formed at both ends thereof, by the second seated hooks 52a, 52a for the second cables 58, 58. The middle first hook 51a is rotatably fitted over the shaft 47b. With such a construction, the size of the connecting portion becomes smaller and the cost is further reduced.
Figs. 13 to 15 show a fourth embodiment in which the above two hydraulic cylinders 41, 42 are replaced by a single hydraulic cylinder 41b. A bottom end 43b of the hydraulic cylinder 41b is pivotally connected by a pin 14b, along with a lower portion of an outer box 71, to brackets 13b provided on the body frame 11. A rod 45b of the hydraulic cylinder 41b is pivotally connected by a pin 16 to an upper portion of an inner box 72. Upon extension and contraction of the rod 45b, the inner box 72 is vertically moved along inner surfaces of the outer box 71.
A first hook 51b for the first cable 55 is provided on a front surface of the inner box 72 in its upper portion.
The pin 16 has female threads formed at both ends thereof with the second hooks 52a screwed to the female threads.
The pin 16 is rotatable about the centers of holes formed through the rod 45b and the inner box 72 for insertion of the pin 16.
With such a construction, since the bending forces exerted from the first cable 55 and the second cables 58 are borne by both the inner box 72 and the outer box 71, the single hydraulic cylinder 41b is enough to construct the device. Accordingly, the connecting portion for the two hydraulic cylinders 41, 42 used in the foregoing embodiments are no longer required, resulting in the simpler structure and the lower cost.
INDUSTRIAL APPLICABILITY
The present invention is useful as a counterweight mounting/dismounting device which is simple in structure, enables a counterweight to be easily mounted and dismounted, and is less costly.
COUNTERWEIGHT MOUNTING/DISMOUNTING DEVICE
TECHNICAL FIELD
The present invention relates to a counterweight mounting/dismounting device for use in construction vehicles such as hydraulic excavators and cranes.
BACKGROUND ART
A prior art counterweight mounting/dismounting device for hydraulic excavators will be described with reference to Fig. 16. A traveling undercarriage 21 of a hydraulic excavator 20 is able to run back and forth by a travel motor (not shown). An upper revolving turret 23 capable of revolving by a turn motor (not shown) is mounted on the traveling undercarriage 21. The upper revolving turret 23 is provided with a working attachment 30, a machine cab 26, an operator cabin 27 and a counterweight 28a. The working attachment 30 comprises a boom 31, an arm 33, a bucket 35 and a plurality of hydraulic cylinders 32, 34, 36, and is operated to carry out the work of digging earth and sand. The counterweight 28a is fixed onto a rear portion of the upper revolving turret 23 by bolts or the like for balancing against both the working attachment 30 and the working load.
For large-sized hydraulic excavators, however, it is often required to dismount a counterweight and transport the same separately because the excavator weight exceeds the value prescribed by the Road Traffic Act when transported in a full-equipped state. In addition, a crane truck must be prepared to mount and dismount the counterweight and, hence, the expenditure increases. To solve such a problem, there are known techniques wherein a counterweight mounting/-dismounting device is equipped on a hydraulic excavator.
According to Japanese Utility Model Publication No.
5-3568, for example, a cable is extended from a hook provided onxp'theear surface of a boom of a working attachment to a hook on the top of a counterweight through a pulley provided at the upper end of a rear stand on an excavator body. By raising and lowering the boom about its base end, the cable is moved to lift up and down the counterweight. Also, according to Japanese Utility Model Laid-Open No. 59-5669, a cable is extended from a hook provided on the rear surface of a boom of a working attachment to a hook on the top of a counterweight through a pulley provided at the upper end of a link which is turnably attached to a rear stand on an excavator body.
The counterweight is moved forth and back by turning the CA 02224703 1997-12-1~
link with an actuator, and is lifted up and down by raising and lowering the boom about its base end.
Further, according to Japanese Utility Model Laid-Open No. 62-21160, a cable is extended from a hook provided on the rear surface of a boom of a working attachment to a hook on the top of a counterweight through a pulley provided at the upper end of a mast which is turnably attached to a rear portion on an excavator body.
The counterweight is moved forth and back by turning the mast with an actuator, and is lifted up and down by raising and lowering the boom about its base end.
Moreover, according to Japanese Utility Model Laid-Open No. 61-141363, a cable is extended from a hook provided at the upper end of a rear stand on an excavator body to a hook on the top of a counterweight through a pulley provided on the rear surface of a boom of a working attachment, a pulley provided on the stand, and a pulley provided on a link which is turnably attached to the stand. Further, a hook provided at the upper end of the link and a hook provided on an arm of the working attachment are interconnected by a cable. The counterweight is moved forth and back by turning the arm of the working attachment, and is lifted up and down by raising and lowering the boom about its base end.
However, any of the foregoing prior art devices has had the problems of complicated structure, expensive cost and complex mounting/dismounting operation, because of requiring one or more pulleys, a pulley mounting stand, a link unit for changing the pulley position, and so on.
DISCLOSURE OF THE INVENTION
The present invention has been accomplished with a view of the foregoing problems in the prior art, and its object is to provide a counterweight mounting/dismounting device which enables a counterweight to be easily mounted and dismounted, and which is less costly.
With a first aspect of the counterweight mounting/-dismounting device according to the present invention, in a construction vehicle comprising an upper revolving turret, a boom attached to a front portion of the upper revolving turret, and a counterweight detachably mounted on a rear portion of the upper revolving turret, the counterweight mounting/dismounting device comprises a hydraulic cylinder pivotally attached to and support on a frame of the upper revolving turret, a first cable interconnecting the distal end of a rod of the hydraulic cylinder and the boom, and a second cable interconnecting the distal end of the rod and the counterweight, the counterweight being lifted up and down by extending and contracting the hydraulic cylinder and raising and CA 02224703 1997-12-1~
lowering the boom about the boom base end.
The first cable may interconnect a first hook attached to the distal end of the rod and a hook provided on the boom, and the second cable may interconnect a second hook attached to the distal end of the rod and a hook provided on the counterweight. Further, a connecting shaft may be attached to the distal end of the rod, and the first hook, the second hook and the distal end of the rod may be each rotatable about the connecting shaft.
Preferably, the counterweight is formed with a recess in which the hydraulic cylinder can be arranged. Also preferably, the position at which the base end of the hydraulic cylinder is attached to the frame is closer to the boom than a vertical line passing a longitudinal centroid position of the counterweight, and the position at which the first cable is connected to the distal end of the rod is rearer in the longitudinal direction of the vehicle than the attachment position of the base end of the hydraulic cylinder. Further, the hydraulic cylinder may comprise a plurality of hydraulic cylinders, and the plurality of hydraulic cylinders may be attached at their distal ends to the frame and are arranged on both sides of a transverse centroid position of the counterweight.
With a second aspect of the counterweight mounting/-dismounting device according to the present invention, the CA 02224703 1997-12-1~
device comprises a hydraulic cylinder pivotally attached to and supported on a frame of an upper revolving turret, brackets provided on the frame, an outer box pivotally attached to the brackets, an inner box pivotally attached to the distal end of a rod of the hydraulic cylinder and being able to move vertically along inner surfaces of the outer box, a first cable interconnecting the distal end of the rod and the boom, and a second cable interconnecting the distal end of the rod and the counterweight, the counterweight being lifted up and down by extending and contracting the hydraulic cylinder and raising and lowering the boom about the base end.
According to the present invention constituted as set forth above, when dismounting the counterweight, the boom is set to a forward inclined position and the first cable is stretched to interconnect the first hook and the boom hook. Subsequently, the second cable is stretched to interconnect the second hook and the counterweight hook.
Then, for dislodging the counterweight from the upper revolving turret, lock bolts are removed and the hydraulic cylinder is extended to lift up the counterweight. By turning the boom rearward in this condition, the counterweight is separated from the body frame and moved downward. After the boom has been moved to a rearward inclined position, by contracting the hydraulic cylinder, CA 02224703 1997-12-1~
the counterweight is further moved downward so as to rest on the ground.
The operation of mounting the counterweight can be basically performed through steps which are reversal of the foregoing steps. More specifically, the boom is set to the rearward inclined position, the first and second cables are stretched between the hooks, and the hydraulic cylinder is extended to lift up the counterweight. By turning the boom forward in this condition, the counterweight is raised without contacting the body frame.
After the counterweight has been moved to a location just above its mount position, the turning of the boom is stopped and the hydraulic cylinder is contracted, whereby the counterweight is moved downward so as to seat on the body frame. The counterweight is then fixed in place by setting the lock bolts.
Thus, since the counterweight mounting/dismounting device has the simple structure achievable just by preparing the hydraulic cylinder, the hook attached to the distal end of the rod, and the cables for lifting the counterweight up and down, it is possible to easily carry out the operation of mounting/dismounting the counterweight and reduce the cost.
BRIEF DESCRIPTION OF THE DRAWINGS
Fig. 1 is a side view of a counterweight mounting/-dismounting device according to a first embodiment of the present invention, Figs. 2A and 2B are detailed views of the counterweight mounting/dismounting device shown in Fig. 1, in which: Fig. 2A is a side view showing a counterweight and hydraulic cylinders in a mounted state and Fig. 2B is a perspective view of the counterweight, Fig. 3 is a view looking from the direction of arrow III in Fig. 2A, Fig. 4 is a hydraulic circuit diagram of the counterweight mounting/dismounting device according to the first embodiment, Figs. 5 to 8 are views for explaining the operation of the counterweight mounting/dismounting device according to the first embodiment, in which:
Fig. 5 is a first operation explaining view, Fig. 6 is a second operation explaining view, Fig. 7 is a third operation explaining view, and Fig. 8 is a fourth operation explaining view, Fig. 9 is a side view showing the counterweight according to the first embodiment in a state rested on the ground, Fig. 10 is a sectional view of a hydraulic cylinder interconnecting portion of a counterweight mounting/-CA 02224703 1997-12-1~
dismounting device according to a second embodiment of the present invention, Fig. 11 is an explanatory view showing hydraulic cylinders, in a mounted state, of a counterweight mounting/dismounting device according to a third embodiment of the present invention, Fig. 12 is a view looking from the direction of arrow XII in Fig. 12, Fig. 13 is an explanatory view showing hydraulic cylinders, in a mounted state, of a counterweight mounting/dismounting device according to a fourth embodiment of the present invention, Fig. 14 is an explanatory view taken along section XIV - XIV in Fig. 13, Fig. 15 is an enlarged view taken along section XV -XV in Fig. 14, and Fig. 16 is a side view of a prior art hydraulic excavator.
BEST MODE FOR CARRYING OUT THE INVENTION
Preferred embodiments of the present invention will be hereinafter described in detail with reference the attached drawings.
Fig. 1 shows a first embodiment in which a hook 56 is fixed to a boom 31. Hydraulic cylinders 41, 42 are connected to a counterweight 28 through cables 58, 58 (see Fig. 2). A first cable 55 is secured to one end of each of the hydraulic cylinders 41, 42 and the hook 56 through shackles 57, 57.
Referring to Figs. 2A and 2B, the counterweight 28 is detachably mounted by bolts 12 to a body frame 11 arranged inside an upper revolving turret 23. The counterweight 28 has a hanging hook 29 provided on its upper surface and positioned to lie on a vertical line passing the centroid position W. Bottom sides 43, 44 of the hydraulic cylinders 41, 42 are pivotally attached by pins 14 to brackets 13 provided on the body frame 11. The center of each hole to which the pin 14 is fitted is positioned nearer to a front portion of the body than the centroid position W of the counterweight 28 by a distance L when the counterweight 28 is in a mounted state. A recess 28b is formed in a central portion of the counterweight 28 to provide a space enough to arrange the two hydraulic cylinders 41, 42 therein.
Referring to Fig. 3, rods 45, 46 of the hydraulic cylinders 41, 42 are fixed by using stoppers 48 to a shaft (connecting shaft) 47 having female threads formed at both ends thereof. A first hook 51 (see Fig. 2A) for the first cable 55 and second hooks 52 for the second cables 58 are rotatably fitted over a central portion and both end CA 02224703 1997-12-1~
portions of the shaft 47, respectively. Each of the second cables 58 has one end connected to the hook 29 provided on the counterweight 28 through a shackle 59, and the other end connected to the second hook 52 through a shackle 59.
Fig. 4 shows a hydraulic circuit for operating the hydraulic cylinders 41, 42. A hydraulic pump 61 for driving the hydraulic cylinders 32, 34, 36 of the working attachment 30 is also employed as a hydraulic source. A
rotary valve 64 is provided to switch over the supply of pressure oil between a first main valve 62 through which the pressure oil is supplied to the hydraulic cylinders 32, 34, 36 and a second main valve 63 for operating the counterweight 28. A counterbalance valve 65 is disposed between the second main valve 63 and the hydraulic cylinders 41, 42.
The operation of dismounting the counterweight with the above-described construction will now be described below. When the counterweight 28 is kept mounted on the body frame 11 as shown in Figs. 1 to 3 and 5, the rods 45, 46 of the hydraulic cylinders 41, 42 are in a contracted state. In this condition, the first cable 55 is stretched between the hook 56 of the boom 31 and the first hook 51 for the hydraulic cylinders 41, 42 through the shackles 57. Then, the two cables 58 are stretched between the hook 29 of the counterweight 28 and the second hook 52 for the hydraulic cylinders 41, 42 through the shackles 59.
Next, the boom 31 iS turned forward to bring the first cable 55 into a state where it is slightly tensioned. The positions of the boom 31, the hydraulic cylinders 41, 42 and the counterweight 28 at this time are assumed to be initial positions, as shown in Fig. 5. The whole of an excavator under this condition is shown in Fig. 1. Subsequently, the bolts 12 for locking the counterweight 28 in the mounted state are removed. Then, after switching over the rotary valve 64 shown in Fig. 4 so as to supply the pressure oil to the second main valve 63 side, the second main valve 63 iS shifted to an "extension" position indicated in Fig. 4. Upon this shift of the second main valve 63, as shown in Fig. 6, the rods 45, 46 of the hydraulic cylinders 41, 42 are extended to exert a tension on the second cables 58, causing the counterweight 28 to start floating. When the rods 45, 46 are further extended, the tip ends of the rods 45, 46 reach a maximum length in a position Q and, at the same time, the counterweight 28 iS lifted upward and moved to a position A.
Next, after switching over the rotary valve 64 SO as to supply the pressure oil to the first main valve 62 side, the boom 31 iS turned rearward as shown in Fig. 7, whereupon the counterweight 28 is separated from the frame 11 and moved downward. By further turning the boom 31 rearward, the boom 31 reaches a fully rearward inclined position, the rods 45, 46 take a position R, and the counterweight 28 moves to a position B. In this condition, the rotary valve 64 is switched over so as to supply the pressure oil to the second main valve 63 side, the second main valve 63 is shifted to a "contraction"
position (see Fig. 4), and the rods 45, 46 are contracted as shown in Fig. 8. As a result, the rods 45, 46 take a position S and the counterweight 28 is moved downward to a position D where it rests on the ground. Since the counterbalance valve 65 is operated in the course of the above downward movement of the counterweight 28, it is possible to prevent the counterweight 28 from dropping by its own weight. The whole of an excavator under this condition is shown in Fig. 9.
After the counterweight 28 has been rested on the ground, the two second cables 58 are removed with the rods 45, 46 held in their shortest positions. Then, the boom 31 is turned forward and, when the rods 45, 46 are moved to a position P shown in Fig. 5, the hydraulic cylinders 41, 42 are secured to the frame 11 by respective fixtures (not shown). The operation of dismounting the counterweight 28 is then completed by removing the first CA 02224703 l997-l2-l~
cable 55. While the operation of dismounting the counterweight 28 has been described above, the operation of mounting the counterweight 28 can be performed through steps which are reversal of the foregoing steps.
With the first embodiment described above, the two hydraulic cylinders 41, 42 are connected together by the shaft 47 with the first hook 51 held therebetween and the second hooks 52 are provided at both ends of the shaft 47.
Further, the hook 5 6 of the boom 31 and the first hook 51 in the cylinder connecting portion are interconnected by the first cable 55, and the hook 29 of the counterweight 28 and the second hooks 52 in the cylinder connecting portion are interconnected by the two second cables 58.
Therefore, the counterweight 28 can be easily mounted and dismounted by extending and contracting the hydraulic cylinders 41, 42 and raising and lowering the boom 31 about its base end. Also, since the second cables 58 have a sufficient length, the counterweight 28 can be easily positioned for alignment when the second cables 28 are attached to the counterweight 28 for mounting it. In addition, since the hydraulic cylinders 41, 42 each have a sufficient stroke, the counterweight 28 can be moved downward so that it completely rests on the ground.
The first hook 51 and the two second hooks 52 are freely rotatably about the shaft 47, and the forces exerted from the first cable 55 and the second cables 58 are transmitted through the center of the shaft 47.
Therefore, the hydraulic cylinders 41, 42 are subjected to no bending load, which makes it possible to smoothly operate the hydraulic cylinders 41, 42 and reduce the size thereof. Also, since the mounting/dismounting device comprises only the two hydraulic cylinders 41, 42, the portion for connecting the hydraulic cylinders 41, 42 together, and the cables 55, 58, 58, conventionally employed members such as a stand, a pulley and a link are no longer required, which results in the simplified structure and the reduced cost in addition to the above size reduction.
Other embodiments of the device for mounting/-dismounting the counterweight 28 will be described below.
Fig. 10 shows an essential part of a second embodiment. The rods 45, 46 of the hydraulic cylinders 41, 42 are fixed to a shaft 47a, which has female threads formed at both ends thereof, by second seated hooks 52a for the second cables 58. The first hook 51 for the first cable 55 is rotatably fitted over a central portion of the shaft 47a, and the shaft 47a is rotatable about the centers of holes formed in the rods 45, 46 for insertion of the shaft 47a. With such a construction, the structure is simplified and the cost is further reduced.
CA 02224703 1997-12-1~
Figs. 11 and 12 show a third embodiment. Spherical bearings 49, 49 are fitted respectively over bottom ends 43a, 44a of the hydraulic cylinders 41a, 42a and attached through pins 14a to brackets 13a provided on the frame 11.
Spherical bearings 49, 49 are fitted respectively over rods 45a, 46a of the hydraulic cylinders 41a, 42a. A
first hook 51a for the first cable 55 is held at the middle between the spherical bearings 49, 49, and inner cylinders 49a, 49a of the spherical bearings 49, 49 are fixed to a shaft 47b, which has female threads formed at both ends thereof, by the second seated hooks 52a, 52a for the second cables 58, 58. The middle first hook 51a is rotatably fitted over the shaft 47b. With such a construction, the size of the connecting portion becomes smaller and the cost is further reduced.
Figs. 13 to 15 show a fourth embodiment in which the above two hydraulic cylinders 41, 42 are replaced by a single hydraulic cylinder 41b. A bottom end 43b of the hydraulic cylinder 41b is pivotally connected by a pin 14b, along with a lower portion of an outer box 71, to brackets 13b provided on the body frame 11. A rod 45b of the hydraulic cylinder 41b is pivotally connected by a pin 16 to an upper portion of an inner box 72. Upon extension and contraction of the rod 45b, the inner box 72 is vertically moved along inner surfaces of the outer box 71.
A first hook 51b for the first cable 55 is provided on a front surface of the inner box 72 in its upper portion.
The pin 16 has female threads formed at both ends thereof with the second hooks 52a screwed to the female threads.
The pin 16 is rotatable about the centers of holes formed through the rod 45b and the inner box 72 for insertion of the pin 16.
With such a construction, since the bending forces exerted from the first cable 55 and the second cables 58 are borne by both the inner box 72 and the outer box 71, the single hydraulic cylinder 41b is enough to construct the device. Accordingly, the connecting portion for the two hydraulic cylinders 41, 42 used in the foregoing embodiments are no longer required, resulting in the simpler structure and the lower cost.
INDUSTRIAL APPLICABILITY
The present invention is useful as a counterweight mounting/dismounting device which is simple in structure, enables a counterweight to be easily mounted and dismounted, and is less costly.
Claims (7)
1. In a construction vehicle comprising an upper revolving turret, a boom attached to a front portion of said upper revolving turret, and a counterweight detachably mounted on a rear portion of said upper revolving turret, a counterweight mounting/dismounting device comprising:
a hydraulic cylinder (41, 42) pivotally attached to and supported on a frame (11) of said upper revolving turret (23), a first cable (55) interconnecting the distal end of a rod (45, 46) of said hydraulic cylinder (41, 42) and said boom (31), and a second cable (58) interconnecting the distal end of said rod (45, 46) and said counterweight (28), said counterweight (28) being lifted up and down by extending and contracting said hydraulic cylinder (41, 42), the distal end of said rod (45, 56) being swung in the longitudinal direction by raising and lowering said boom (31) about the boom base end.
a hydraulic cylinder (41, 42) pivotally attached to and supported on a frame (11) of said upper revolving turret (23), a first cable (55) interconnecting the distal end of a rod (45, 46) of said hydraulic cylinder (41, 42) and said boom (31), and a second cable (58) interconnecting the distal end of said rod (45, 46) and said counterweight (28), said counterweight (28) being lifted up and down by extending and contracting said hydraulic cylinder (41, 42), the distal end of said rod (45, 56) being swung in the longitudinal direction by raising and lowering said boom (31) about the boom base end.
2. A counterweight mounting/dismounting device according to Claim 1, wherein said hydraulic cylinder (41, 42) comprises two hydraulic cylinders (41, 42) and said second cable (58) comprises two second cables (58, 58), and said two second cables (58, 58) respectively interconnect two second hooks (52, 52) attached to the distal ends of the rods (45, 46) of said two hydraulic cylinders (41, 42) and two hooks (29, 29) provided on said counterweight (28) in positions outward of said two hydraulic cylinders (41, 42).
3. A counterweight mounting/dismounting device according to Claim 2, further comprising a connecting shaft (47) attached to the distal ends of said two rods (45, 46), and a first hook (51) serving as a joint portion with said first cable (55) and attached to the distal ends of said two rods (45, 46), wherein said first hook (51), said two second hooks (52) and the distal ends of said two rods (45, 46) are each rotatable about said connecting shaft (47).
4. (deleted)
5. A counterweight mounting/dismounting device according to Claim 1, wherein a recess (28b) is formed in a transverse central portion of said counterweight (28) on the side of said counterweight (28) nearer to said boom (31), the base end of said hydraulic cylinder (41, 42), at which said hydraulic cylinder (41, 42) is attached to said frame (11), being arranged in said recess (28b), the position of the base end of said hydraulic cylinder (41, 42) is closer to said boom (31) than a vertical line passing a longitudinal centroid position (W) of said counterweight (28), and is located in said recess (28b), and the position at which said first cable (55) is connected to the distal end of said rod (45, 46) is rearer in the longitudinal direction of said vehicle (20) than the attachment position of the base end of said hydraulic cylinder (41, 42).
6. (deleted)
7. In a construction vehicle comprising an upper revolving turret, a boom attached to a front portion of said upper revolving turret, and a counterweight detachably mounted on a rear portion of said upper revolving turret, a counterweight mounting/dismounting device comprising:
a hydraulic cylinder (41b) pivotally attached to and supported on a frame (11) of said upper revolving turret (23), brackets (13b) provided on said frame (11), an outer box (71) pivotally attached to said brackets (13b), an inner box (72) pivotally attached to the distal end of a rod (45b) of said hydraulic cylinder (41b) and being able to move vertically along inner surfaces of said outer box (71), a first cable (55) interconnecting the distal end of said rod (45b) and said boom (31), and a second cable (58) interconnecting the distal end of said rod (45b) and said counterweight (28), said counterweight (28) being lifted up and down by extending and contracting said hydraulic cylinder (41b) and raising and lowering said boom (31) about the boom base end.
a hydraulic cylinder (41b) pivotally attached to and supported on a frame (11) of said upper revolving turret (23), brackets (13b) provided on said frame (11), an outer box (71) pivotally attached to said brackets (13b), an inner box (72) pivotally attached to the distal end of a rod (45b) of said hydraulic cylinder (41b) and being able to move vertically along inner surfaces of said outer box (71), a first cable (55) interconnecting the distal end of said rod (45b) and said boom (31), and a second cable (58) interconnecting the distal end of said rod (45b) and said counterweight (28), said counterweight (28) being lifted up and down by extending and contracting said hydraulic cylinder (41b) and raising and lowering said boom (31) about the boom base end.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP7/199229 | 1995-07-12 | ||
| JP19922995 | 1995-07-12 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2224703A1 true CA2224703A1 (en) | 1997-01-30 |
Family
ID=16404306
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002224703A Abandoned CA2224703A1 (en) | 1995-07-12 | 1996-07-10 | Device for mounting and dismounting counterweight |
Country Status (2)
| Country | Link |
|---|---|
| CA (1) | CA2224703A1 (en) |
| WO (1) | WO1997003013A1 (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| BE1024764B1 (en) * | 2016-11-30 | 2018-06-28 | C M L Ind S A | Construction machine |
| US10066365B2 (en) * | 2016-01-22 | 2018-09-04 | Hpm—Hydraulic Performance Machines Srl | Public works vehicle provided with counterweight lifting system |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP5122786B2 (en) * | 2005-11-18 | 2013-01-16 | 株式会社小松製作所 | Counterweight attachment / detachment device |
| US20170051473A1 (en) * | 2015-08-21 | 2017-02-23 | Caterpillar Inc. | Machine counterweight installation and removal |
Family Cites Families (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS4835281Y1 (en) * | 1970-11-11 | 1973-10-24 | ||
| JPS6221160U (en) * | 1985-07-17 | 1987-02-07 | ||
| JP2562475Y2 (en) * | 1990-09-14 | 1998-02-10 | 石川島建機 株式会社 | Counterweight attachment / detachment device for construction machinery |
-
1996
- 1996-07-10 CA CA002224703A patent/CA2224703A1/en not_active Abandoned
- 1996-07-10 WO PCT/JP1996/001912 patent/WO1997003013A1/en active Search and Examination
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US10066365B2 (en) * | 2016-01-22 | 2018-09-04 | Hpm—Hydraulic Performance Machines Srl | Public works vehicle provided with counterweight lifting system |
| BE1024764B1 (en) * | 2016-11-30 | 2018-06-28 | C M L Ind S A | Construction machine |
Also Published As
| Publication number | Publication date |
|---|---|
| WO1997003013A1 (en) | 1997-01-30 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| EEER | Examination request | ||
| FZDE | Discontinued | ||
| FZDE | Discontinued |
Effective date: 20000710 |