US4368521A
Expired / Lapsed
US
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Method and apparatus for dragline tightline protection
Assignee: Indresco Inc
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Filing: 1980-09-30
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Granted: 1983-01-11
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Expires: 2000-09-30
Abstract
Abstract Method and Apparatus are described for effecting tightline protection in a dragline excavating machine or the like. The described technique uses optical shaft encoders to provide binary coded decimal inputs related to the amount of hoist and drag rope paid out to digital logic. The control algorithm for the digital logic considers both static and dynamic conditions to optimize the permissible operating range of the dragline. In the digital logic device, signals corresponding with the amount of rope paid out from the dragline hoist and drag drums are added and compared with predetermined constants to sense a tightline condition. If either a static or dynamic tightline condition is sensed, indications are provided and cause motion brakes to be set in the machine. The same data can be used to electronically indicate limits of bucket travel.
Inventors
- 👤 II John T. Sholes
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 03:00
CPC Classifications
E; E02; E02F; E02F9/00; E02F9/20; E02F9/2025; E02F3/00; E02F3/04; E02F3/46; E02F3/48
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
112 words
A method of preventing tightline condition in a dragline or the like, comprising the steps of: sensing the amount of hoist rope paid out from a hoist drum, sensing the amount of drag rope paid out by a drag drum, adding the values of the sensed amounts of drag and hoise rope paid out to produce a sum signal having a value corresponding to the sum of the values of hoist and drag rope paid out, comparing the value of said sum signal with a predetermined constant and halting dragline operation when the result of said comparing step is that said sum signal is of a value less than said predetermined constant.
Claim 2
Independent Claim
112 words
A method of preventing tightline condition in a dragline or the like, comprising the steps of: sensing the amount of hoist rope paid out from a hoist drum, sensing the amount of drag rope paid out by a drag drum, adding the values of the sensed amounts of drag and hoise rope paid out to produce a sum signal having a value corresponding to the sum of the values of hoist and drag rope paid out, comparing the value of said sum signal with a predetermined constant and halting dragline operation when the result of said comparing step is that said sum signal is of a value less than said predetermined constant.
Claim 3
Dependent Claim
107 words
The method defined in claim 1 further comprising the additional steps of: determining the velocity at which rope is paid out from said drums and producing a corresponding velocity signal, comparing said velocity signal with a predetermined velocity limit value and producing a velocity enable signal when said velocity signal exceeds in value said velocity limit value, comparing said sum signal with a second predetermined constant upon the appearance of said velocity enable signal to produce a dynamic tightline output signal if said sum signal is less than or equal to said second predetermined constant and halting dragline operation upon appearance of said dynamic tightline output signal.
Claim 4
Independent Claim
25 words
The method defined in claims 1 or 2 wherein said sensing steps comprise sensing, respectively, the number of revolutions of said hoist and drag drums.
Claim 5
Dependent Claim
14 words
The method defined in claim 3 wherein said numbers of revolutions are optically sensed.
Claim 6
Dependent Claim
230 words
Apparatus for determining the existence of given operating conditions in a dragline or the like, comprising: first means for sensing the amount of hoist rope paid out from a hoist drum and producing a first sensing signal having a value corresponding thereto, second means for sensing the amount of drag rope paid out from a drag drum and for producing a second sensing signal having a value corresponding thereto, adder means for producing a sum signal having a value corresponding to the added values of said first and second sensing signals, detector means for producing a velocity signal having a value corresponding to the rate at which rope is paid out from said drums, first comparator means for producing a velocity enable signal when said velocity signal equals a predetermined value, second comparator means for comparing said sum signal and a first predetermined constant when enabled by said velocity enable signal to produce a first comparator output signal when said sum signal is less than or equal to said first predetermined constant, third comparator means for comparing said sum signal and a second predetermined constant for producing a third comparator output signal when said sum signal is equal to or less than said second predetermined constant, and switch means actuated by either of said second or third comparator output signals indicating the presence of a dynamic or static tightline condition.
Claim 7
Dependent Claim
230 words
Apparatus for determining the existence of given operating conditions in a dragline or the like, comprising: first means for sensing the amount of hoist rope paid out from a hoist drum and producing a first sensing signal having a value corresponding thereto, second means for sensing the amount of drag rope paid out from a drag drum and for producing a second sensing signal having a value corresponding thereto, adder means for producing a sum signal having a value corresponding to the added values of said first and second sensing signals, detector means for producing a velocity signal having a value corresponding to the rate at which rope is paid out from said drums, first comparator means for producing a velocity enable signal when said velocity signal equals a predetermined value, second comparator means for comparing said sum signal and a first predetermined constant when enabled by said velocity enable signal to produce a first comparator output signal when said sum signal is less than or equal to said first predetermined constant, third comparator means for comparing said sum signal and a second predetermined constant for producing a third comparator output signal when said sum signal is equal to or less than said second predetermined constant, and switch means actuated by either of said second or third comparator output signals indicating the presence of a dynamic or static tightline condition.
Claim 8
Dependent Claim
33 words
The apparatus defined in claim 5 wherein said first and second sensing means produce said first and second sensing signals in accordance with the number of revolutions of said hoist and drag drums.
Claim 9
Dependent Claim
25 words
The apparatus defined in claim 6 wherein said first and second sensing means optically sense the number of revolutions of said hoist and drag drums.
Claim 10
Dependent Claim
52 words
The apparatus defined in claim 5 further comprising fourth comparator means for comparing said first sensing signal with a value corresponding with a predetermined value of hoist rope to be paid out from said hoist drum and for producing a fourth comparator output signal indicating amount of said hoist rope paid out.
Claim 11
Dependent Claim
50 words
The apparatus defined in claim 5 further comprising a fifth comparator means for comparing said second sensing signal with a predetermined value of drag rope to be paid out from said drag drum and for producing a fifth comparator output signal indicating the amount of said drag rope paid out.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1986-01-10 | 1986-07-12 | 1987-01-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1990-01-10 | 1990-07-12 | 1991-01-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1994-01-10 | 1994-07-12 | 1995-01-11 | $7700.00 | Window Closed / Lapsed |