Dual drive system for dragline with power interlock

• US 4,284,265 A
• Filed: 12/03/1979
• Issued: 08/18/1981
• Est. Priority Date: 03/07/1979
• Status: Expired due to Term

• Current Assignee: Manitowoc Crane Companies LLC
• Original Assignee: The Manitowoc Company, Inc.
• Inventors: Morrow, James G. Sr.
• Primary Examiner(s): Jillions, John M.
• Application Number:
  US06/099,916
• Time in Patent Office: 624 Days
• Field of Search: 254/315, 254/317, 254/318, 254/319, 254/321, 254/299, 254/303, 254/309, 254/310, 254/311, 37/115, 37/116, 37/135, 37/136, 192/3.25, 74/718, 60/363, 414/625
• US Class Current: 254/317
• CPC Class Codes: B66D 1/44 pneumatic of hydraulic
• CPC Class Codes: E02F 3/48 Drag-lines
• CPC Class Codes: E02F 9/20 Drives; Control devices gearings in general F16H; controlling in general G05; electric multi-motor drives H02K, H02P

Abstract

Separate torque converters are selectively clutched to the hoist and drag drums of a dragline machine with a selectively engageable clutch providing a power interlock of the output of both torque converters to either one of the drums as desired. The application and control of torque from the two torque converters to the hoist drum is in parallel and to the drag drum is in series progressive, i.e., the drag converter being engaged first and going from zero to maximum while the hoist converter goes from zero to about fifty percent of capacity as the drag converter reaches maximum. The reserve torque in the hoist converter may be selectively applied to the hoist drum to step the drag bucket up if the drag drum approaches a stall condition. The hoist converter may also be selectively engaged to apply a predetermined hold back force during bucket lowering. Another clutch may be engaged to interlock the two drums together for joint operation by the hoist converter. Thus, dragline holdback during hoisting may be achieved by the drag drum brakes, the drag drum converter or the drum interlock thereby providing the operator with considerable flexibility in controlling the path of the drag bucket during hoisting.

Claims

1. A split drive system for a dragline having a hoist drum and a drag drum comprising, in combination, a power source, means including a first torque converter having an output shaft and a first selectively engageable clutch for interconnecting said power source and said hoist drum, means including a second torque converter having an output shaft and a second selectively engageable clutch for interconnecting said power source and said drag drum, power interlock control means for selectively coupling said output shafts together, hoist control means movable in one direction for engaging said first clutch and for modulating said first and second torque converters, drag control means movable in one direction for engaging said second clutch and for modulating said second torque converter, control means for automatically rendenering said drag control means operative when moved in said one direction for progressively modulating said second torque converter up to a predetermined output level and then progressively modulating said first torque converter up to another predetermined output level.

2. The combination defined in claim 1 including means for adjusting said predetermined output level of said second torque converter at which said progressive modulation of said first torque converter begins.

3. The combination defined in claim 2 wherein said control means is pneumatically actuated and said adjusting means includes means for regulating the pneumatic pressure delivered respectively to said first and second torque converter modulating means.

4. The combination defined in claim 1 wherein said hoist control means is operative when moved in said one direction to automatically take over modulation of said first torque converter from said drag control means.

5. The combination defined in claim 1 wherein said hoist control means is operative when moved in the opposite direction to disengage said power interlock means to disable progressive modulation of said first torque converter by said drag control means and instead to actuate said first torque converter at a predetermined output level.

7. The combination defined in claim 5 wherein said control means includes a normally open valve interposed between said drag control means and said progressive modulating means for said first torque converter and said hoist control means is operative when moved in said the opposite direction to close said valve.

8. The combination defined in claim 5 wherein said control means includes a selectively operable power interlock control valve interposed between a pneumatic source and said power interlock means.

9. The combination defined in claim 8 wherein said control means includes a normally open valve interposed between said power interlock means and said power interlock control valve and said hoist control means is operative when moved in said opposite direction to close said valve.

11. The combination defined in claim 1 wherein each of said first and second clutches includes a pneumatic actuator biased toward disengagement and said means for modulating said first and second torque converters each includes a pneumatic actuator biased toward neutral such that said clutch actuators are operable to partially engage said clutches prior to modulation of said respective torque converters.

12. The combination defined in claim 11 including a shuttle valve interposed between said hoist control means and said first clutch actuator such that said first clutch is actuated when said hoist control is moved in either direction.

6. The combination defined 5 including means for adjusting said predetermined output level of said first torque converter.

10. The combination defined in claim 6 including a normally closed valve interposed between said modulating means for said first torque converter and said adjusting means and said hoist control means is operative when moved in said opposite direction to close said valve.