CA1116589A - Winch system for controlling closing and lifting of a grab - Google Patents
Winch system for controlling closing and lifting of a grabInfo
- Publication number
- CA1116589A CA1116589A CA000332342A CA332342A CA1116589A CA 1116589 A CA1116589 A CA 1116589A CA 000332342 A CA000332342 A CA 000332342A CA 332342 A CA332342 A CA 332342A CA 1116589 A CA1116589 A CA 1116589A
- Authority
- CA
- Canada
- Prior art keywords
- closing
- holding
- pump
- rope
- hydraulic
- 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
Landscapes
- Control And Safety Of Cranes (AREA)
Abstract
ABSTRACT
A winch arrangement for a crane having a grab, closing rope, and a holding rope, said arrangement having a holding and a closing drum to receive a portion of and apply a force to the closing and holding ropes, a holding and a closing hydraulic motor each of which is coupled to the respective holding or closing drum so as to drive same, and a hydraulic circuit to control the motors to apply a lifting force to both the holding and closing ropes via said holding and closing drums.
A winch arrangement for a crane having a grab, closing rope, and a holding rope, said arrangement having a holding and a closing drum to receive a portion of and apply a force to the closing and holding ropes, a holding and a closing hydraulic motor each of which is coupled to the respective holding or closing drum so as to drive same, and a hydraulic circuit to control the motors to apply a lifting force to both the holding and closing ropes via said holding and closing drums.
Description
5~;~
The present invention relates to cranes and more particularly but not excluslvely to grab cranes.
Grab cranes as presently used in the logging and dredging industries, as well as the general application of grab cranes to pick up bulk materials such as coal, ore, etc., employ a grab consisting usually of two jaws or two shells which open and close to pick up the load and subsequently discharge it. These movements are produced by the actuation of a holding rope and a closing rope. For example, in these conventional cranes the holding rope opens the jaws and the closing rope closes and lifts the jaws. This arrangement has the disadvantage that the function of each rope being separate in that they were not simultaneously employed to lift the load with the result that the cranes are limited in lifting capac-ity since only one of the ropes carries out the lifting function.
It is the object of the present invention to over-come or substantially ameliorate the above disadvantages.
There is disclosed herein a winch arrangement for a crane having a grab, a holding rope and a closing rope, said arrangement comprislng a closing drum to receive a portion of the closing rope and apply force thereto, a holding drum to receive a portion of the closing rope and apply a force there-.. .
to, first means to apply a first torque to the closing drum, second means to apply a second torque to the holding drum, control means for controlling said first and second means so that a lifting force is applied to both the ropes to lift the grab with the effective lifting force applied to said closing rope being greater than the effective lifting force applied *~0 to said holding rope, and wherein said first means includes ~ J
The present invention relates to cranes and more particularly but not excluslvely to grab cranes.
Grab cranes as presently used in the logging and dredging industries, as well as the general application of grab cranes to pick up bulk materials such as coal, ore, etc., employ a grab consisting usually of two jaws or two shells which open and close to pick up the load and subsequently discharge it. These movements are produced by the actuation of a holding rope and a closing rope. For example, in these conventional cranes the holding rope opens the jaws and the closing rope closes and lifts the jaws. This arrangement has the disadvantage that the function of each rope being separate in that they were not simultaneously employed to lift the load with the result that the cranes are limited in lifting capac-ity since only one of the ropes carries out the lifting function.
It is the object of the present invention to over-come or substantially ameliorate the above disadvantages.
There is disclosed herein a winch arrangement for a crane having a grab, a holding rope and a closing rope, said arrangement comprislng a closing drum to receive a portion of the closing rope and apply force thereto, a holding drum to receive a portion of the closing rope and apply a force there-.. .
to, first means to apply a first torque to the closing drum, second means to apply a second torque to the holding drum, control means for controlling said first and second means so that a lifting force is applied to both the ropes to lift the grab with the effective lifting force applied to said closing rope being greater than the effective lifting force applied *~0 to said holding rope, and wherein said first means includes ~ J
2 -a closing hydraulic motor means and a first closing pump means to drive said closing motor means, and said second means includes a holding hydraulic motor means and a second holding pump means to drive said holding motor means, and a first hydraulic circuit coupling the closing pump and closing motor means and a second hydraulic circuit coupling the holding pump and holding motor means, and said control means includes a displacement control hydraulic circuit to adjustably control the output of the said first and second pump means.
A preferred form of the present invention will now be described by way of example with reference to the accom-panying draw.ings wherein:
Fig. 1 is a plan view illustrating a winch arrange-ment;
; ~
- 2(a) -Fig. 2 is a side elevation of the winch arrangement of Fig. l;
Fig. 3 is a sectioned elevation of the winch arrange-ment of Fig. l;
Fig. 4 is a hydraulic circuit including motors and pumps for the winch arrangement of Figs. 1 and 2; and Fig. 5 is a hydraulic control circult to be used with the circuit of Fig. 3.
With reference to Figs. 1 to 3, the winch arrangement 10 comprises a frame 11 rotatably supporting a holding drum 12, a closing drum 13 and a luff drum 14. The holding and closing drums 12 and 13 are coaxially mounted on individual shafts 15 and 16 respectively by means of bearings 17. The holding drum 12 is provided with a gear 18 which meshingly engages three gears 19 (A, B, C) so as to be driven thereby. The gears 19 are each driven by one of shafts 20 ~A, B, C) extending from a respective one of the hydraulic motors 21 ~A, B, C). Similarly the closing drum 13 is provided with a gear 22 driven by hydraulic motors 23 (A, B, C) via shafts 24 (A, B, C) and gears 25 (A, B, C).
The holding drum 12 and closing drum 13 are adapted to receive a holding rope and closing rope respectively, which ropes extend, in the case of a logging crane, to a grab com-prising two pivotally attached jaws which are adapted to engage a bundle. The closing rope engages the jaws so that when a force is applied thereto the jaws move relatively to each other so as to grip the bundle. A lifting force is then applied to both~ropes so as to raise the gripped bundle. To retain the bundle in the jaws a greater proportion of the lifting force required to raise the bundle is applied through the closing ~ .
~ 3 -rope. ~ suitable proportiorl is 60~ of the total load.
~ cJreater force can be applied to the closing rope, ...
as compared to the holding rope, by applyincJ a higher torclue to the closin~ drum 13 by means oE gear ratios. ~ccordingly if a hi~her torque is to be applied to the closin~ drum 13 then the ratio of the pitch circle diameter of gear 22 to gears 25 i5 lar~er tllan the ratio of the pitcll circle diameter oE
gear 18 -to ~ears 19.
Turning now to Fig~ 4 wherein -there is illustrated a hydraulic circuit including the hydraulic motors 23 (A,'B, C) and 21 (A, B, C) which are driven by variable displacement hydraulic pumps 26 (A & B) and 27 (A & B). With reference now to the closing circuit 47, the motors 21, which drive the closing drum 13, are connected with the pumps 27 in parallel by hydraulic lines 28 to 31. The lines 28 and 30 are su~plied with hydraulic fluid under pressure when tihe closing drum 13 is to retract the closing rope, while if lines 29 and 31 are supplied with hydraulic fluid under pressure then the closi.ng drum 13 unwinds the closing rope therefrom. The closing circuit 47 is provided with pressure limit switches 32 and suction limit switch 33 which when activated cause the operation of a brake mechanism to en~a~e drums 12 and 13 to prevent further movement thereof. Control devices 34 are provided to select-ively vary the displacement of the pumps 27. The item 35 indicates a pressure gauge.
Each of the pumps 27 is provided with pressure relief valves 36 and with a hydraulic fluid boost input valve 37 to inject hydraulic fluid into the closed loop circuit 47 to replace fluid leaking therefrom. Similarly the holding circuit 38 is provided with hydraulic lines 39 to ~2 to 5~
connect tlle pumps 26 (~ & B) in parallel wi~h mo-tors 23 (~, B, C) to dr.ive tlle holdi~g drum 12. The circuit 38 is provided with pressure relief valves 43 ancl hydraulic fluid boost inpu-t valves 44. The pumps 26 (A & B) are provided with control devices 45 to selectively vary the displacement of -the pumps 26 (A & B).
Joining the two circuits 47 and 3~ is valve 46 which is adapted to selectively connect the circuits 47 and 38 in parallel. Thus in operation the closing circuit 27 is first activated to close the ~rab, thereafter the two circuits 38 and 47 are placed in parallel by activating valve 46. The pumps 26 and 27 then supply hydraulic fluid under pressure by lines 2~, 30, 39 and 41 to drive motors 23 and ~1. The drums 12 and 13 are then caused to rotate and wind in the holding and closing rope. So that the ropes are progressed at the same rate the displacement of pumps 26 is adjusted so as to be less than pumps 27 in order to compensate for the different gear ratios. Located adjacent -the valve 46 are two pressure switches 67 which ensure that the main control valves 49 and S0 cannot operate electrically until 500 ps.i is present in both the closing circuit 47 and holding circuit 38. This prevents any sudden pressure rise in the event of one rope being slack.
Control of the pumps 26 and 27 to effect up and down movement of the grab as well as rate thereof is achieved by operator control valves 49 and 50. Valve 50 controls the direction and displacement of pumps 26 while valve 49 controls the direction and displacement of pumps 27. The control circuit 48 is provided with hydraulic fluid under pressure through line 51, which fluid is selectively directed by valves 49 and 50 to lines 52 to 55. For example one of lines 52 or 53, if supplicd Wit]l fluicl under pressure, could cause the increase in displacement of pumps 2G while if the other line is supplied with fluid under pressure would cause a reverse displacement to t}lereby drive the motors 23 in the opposite direction. A
similar condition coulc7. be applied to lines 54 and 55. Lines 52 ~ Z 53 al-e provic~cc~ wi.tH~ prcssurc r~ lci~ valvc-~s 5~ cl 57 to regulate the displacement of pumps 26 so as not to exceed the displacement of pumps 27 to thereby ensure that the rate of movement of the holc1ing rope is the same as the closing rope.
The winch assembly 10 is provided with a brake, mechanism 58 for the holding drum 12 and a brake mechanism 59 for the closing drum 13. Both mechanisms 58 and 59 are biased on and are only released by the application of fluid under pxessure to line 60 or 61. However, the control circuit 48 is provided with two safety valves 62 and 63 which are operated by switches 32, 33 and 64. If any one of switches 32, 33 or 64 is activated the pressure is relieved from lines 53 and 54 by activation of valves 62 and 63 which in turn activates valves 65 and 66. Valves 65 and 66 then clrain the fluid from the brake mechanism 58 and 59 to thereby release them to engage and stop drums 12 and 13.
The shuttle valve 67 i.s provided to prevent the hold li.ne loacl from being added to the close line.
A preferred form of the present invention will now be described by way of example with reference to the accom-panying draw.ings wherein:
Fig. 1 is a plan view illustrating a winch arrange-ment;
; ~
- 2(a) -Fig. 2 is a side elevation of the winch arrangement of Fig. l;
Fig. 3 is a sectioned elevation of the winch arrange-ment of Fig. l;
Fig. 4 is a hydraulic circuit including motors and pumps for the winch arrangement of Figs. 1 and 2; and Fig. 5 is a hydraulic control circult to be used with the circuit of Fig. 3.
With reference to Figs. 1 to 3, the winch arrangement 10 comprises a frame 11 rotatably supporting a holding drum 12, a closing drum 13 and a luff drum 14. The holding and closing drums 12 and 13 are coaxially mounted on individual shafts 15 and 16 respectively by means of bearings 17. The holding drum 12 is provided with a gear 18 which meshingly engages three gears 19 (A, B, C) so as to be driven thereby. The gears 19 are each driven by one of shafts 20 ~A, B, C) extending from a respective one of the hydraulic motors 21 ~A, B, C). Similarly the closing drum 13 is provided with a gear 22 driven by hydraulic motors 23 (A, B, C) via shafts 24 (A, B, C) and gears 25 (A, B, C).
The holding drum 12 and closing drum 13 are adapted to receive a holding rope and closing rope respectively, which ropes extend, in the case of a logging crane, to a grab com-prising two pivotally attached jaws which are adapted to engage a bundle. The closing rope engages the jaws so that when a force is applied thereto the jaws move relatively to each other so as to grip the bundle. A lifting force is then applied to both~ropes so as to raise the gripped bundle. To retain the bundle in the jaws a greater proportion of the lifting force required to raise the bundle is applied through the closing ~ .
~ 3 -rope. ~ suitable proportiorl is 60~ of the total load.
~ cJreater force can be applied to the closing rope, ...
as compared to the holding rope, by applyincJ a higher torclue to the closin~ drum 13 by means oE gear ratios. ~ccordingly if a hi~her torque is to be applied to the closin~ drum 13 then the ratio of the pitch circle diameter of gear 22 to gears 25 i5 lar~er tllan the ratio of the pitcll circle diameter oE
gear 18 -to ~ears 19.
Turning now to Fig~ 4 wherein -there is illustrated a hydraulic circuit including the hydraulic motors 23 (A,'B, C) and 21 (A, B, C) which are driven by variable displacement hydraulic pumps 26 (A & B) and 27 (A & B). With reference now to the closing circuit 47, the motors 21, which drive the closing drum 13, are connected with the pumps 27 in parallel by hydraulic lines 28 to 31. The lines 28 and 30 are su~plied with hydraulic fluid under pressure when tihe closing drum 13 is to retract the closing rope, while if lines 29 and 31 are supplied with hydraulic fluid under pressure then the closi.ng drum 13 unwinds the closing rope therefrom. The closing circuit 47 is provided with pressure limit switches 32 and suction limit switch 33 which when activated cause the operation of a brake mechanism to en~a~e drums 12 and 13 to prevent further movement thereof. Control devices 34 are provided to select-ively vary the displacement of the pumps 27. The item 35 indicates a pressure gauge.
Each of the pumps 27 is provided with pressure relief valves 36 and with a hydraulic fluid boost input valve 37 to inject hydraulic fluid into the closed loop circuit 47 to replace fluid leaking therefrom. Similarly the holding circuit 38 is provided with hydraulic lines 39 to ~2 to 5~
connect tlle pumps 26 (~ & B) in parallel wi~h mo-tors 23 (~, B, C) to dr.ive tlle holdi~g drum 12. The circuit 38 is provided with pressure relief valves 43 ancl hydraulic fluid boost inpu-t valves 44. The pumps 26 (A & B) are provided with control devices 45 to selectively vary the displacement of -the pumps 26 (A & B).
Joining the two circuits 47 and 3~ is valve 46 which is adapted to selectively connect the circuits 47 and 38 in parallel. Thus in operation the closing circuit 27 is first activated to close the ~rab, thereafter the two circuits 38 and 47 are placed in parallel by activating valve 46. The pumps 26 and 27 then supply hydraulic fluid under pressure by lines 2~, 30, 39 and 41 to drive motors 23 and ~1. The drums 12 and 13 are then caused to rotate and wind in the holding and closing rope. So that the ropes are progressed at the same rate the displacement of pumps 26 is adjusted so as to be less than pumps 27 in order to compensate for the different gear ratios. Located adjacent -the valve 46 are two pressure switches 67 which ensure that the main control valves 49 and S0 cannot operate electrically until 500 ps.i is present in both the closing circuit 47 and holding circuit 38. This prevents any sudden pressure rise in the event of one rope being slack.
Control of the pumps 26 and 27 to effect up and down movement of the grab as well as rate thereof is achieved by operator control valves 49 and 50. Valve 50 controls the direction and displacement of pumps 26 while valve 49 controls the direction and displacement of pumps 27. The control circuit 48 is provided with hydraulic fluid under pressure through line 51, which fluid is selectively directed by valves 49 and 50 to lines 52 to 55. For example one of lines 52 or 53, if supplicd Wit]l fluicl under pressure, could cause the increase in displacement of pumps 2G while if the other line is supplied with fluid under pressure would cause a reverse displacement to t}lereby drive the motors 23 in the opposite direction. A
similar condition coulc7. be applied to lines 54 and 55. Lines 52 ~ Z 53 al-e provic~cc~ wi.tH~ prcssurc r~ lci~ valvc-~s 5~ cl 57 to regulate the displacement of pumps 26 so as not to exceed the displacement of pumps 27 to thereby ensure that the rate of movement of the holc1ing rope is the same as the closing rope.
The winch assembly 10 is provided with a brake, mechanism 58 for the holding drum 12 and a brake mechanism 59 for the closing drum 13. Both mechanisms 58 and 59 are biased on and are only released by the application of fluid under pxessure to line 60 or 61. However, the control circuit 48 is provided with two safety valves 62 and 63 which are operated by switches 32, 33 and 64. If any one of switches 32, 33 or 64 is activated the pressure is relieved from lines 53 and 54 by activation of valves 62 and 63 which in turn activates valves 65 and 66. Valves 65 and 66 then clrain the fluid from the brake mechanism 58 and 59 to thereby release them to engage and stop drums 12 and 13.
The shuttle valve 67 i.s provided to prevent the hold li.ne loacl from being added to the close line.
Claims (5)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A winch arrangement for a crane having a grab, a holding rope and a closing rope, said arrangement comprising a closing drum to receive a portion of the closing rope and apply force thereto, a holding drum to receive a portion of the closing rope and apply a force thereto, first means to apply a first torque to the closing drum, second means to ap-ply a second torque to the holding drum, control means for controlling said first and second means so that a lifting force is applied to both the ropes to lift the grab with the effective lifting force applied to said closing rope being greater than the effective lifting force applied to said hold-ing rope, and wherein said first means includes a closing hydraulic motor means and a first closing pump means to drive said closing motor means, and said second means includes a holding hydraulic motor means and a second holding pump means to drive said holding motor means, and a first hydraulic cir-cuit coupling the closing pump and closing motor means and a second hydraulic circuit coupling the holding pump and holding motor means, and said control means includes a displacement control hydraulic circuit to adjustably control the output of the said first and second pump means.
2. The arrangement of claim 1 wherein both said motor means are hydraulic motors of equal displacement, and both the pump means are variable displacement hydraulic pumps.
3. The arrangement of claim 1 wherein said first means includes a first gear train coupling said closing motor means with said closing pump means, said second means includes a second gear train coupling said holding motor means with said holding pump means, and the ratio of said first gear train in respect of input speed to output speed is greater than the corresponding ratio of said second gear train.
4. The arrangement of claims 1 or 2 wherein said control circuit actuates said first circuit prior to said second circuit during a lifting operation.
5. The arrangement of claim 2 wherein said control circuit is adapted to regulate the displacement of the hold-ing and closing pump so that the displacement of said holding pump is greater than said closing pump.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| AU517378 | 1978-07-21 | ||
| AUPD5173 | 1978-07-21 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1116589A true CA1116589A (en) | 1982-01-19 |
Family
ID=3695644
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000332342A Expired CA1116589A (en) | 1978-07-21 | 1979-07-23 | Winch system for controlling closing and lifting of a grab |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1116589A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102642787A (en) * | 2012-04-12 | 2012-08-22 | 中国人民解放军装甲兵工程学院 | Vehicle-mounted constant-tension hydraulic capstan |
| CN109987535A (en) * | 2019-05-13 | 2019-07-09 | 河南剑宏科技有限公司 | It is a kind of can rope closing etc. power draw (tensioning) traction rope traction device |
-
1979
- 1979-07-23 CA CA000332342A patent/CA1116589A/en not_active Expired
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102642787A (en) * | 2012-04-12 | 2012-08-22 | 中国人民解放军装甲兵工程学院 | Vehicle-mounted constant-tension hydraulic capstan |
| CN109987535A (en) * | 2019-05-13 | 2019-07-09 | 河南剑宏科技有限公司 | It is a kind of can rope closing etc. power draw (tensioning) traction rope traction device |
| CN109987535B (en) * | 2019-05-13 | 2023-08-11 | 河南剑宏科技有限公司 | Constant force traction (tensioning) traction rope traction device capable of winding rope |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |