US4120364A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Automatic control device for tractor mounted tools
Assignee: American Tractor Equipment Corp
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Filing: 1977-03-03
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Granted: 1978-10-17
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Expires: 1997-03-03
Abstract
Abstract A tractor mounted tool employs a programmable control device to change the angular attitude of the tool to a work surface at a preselected depth and also indicate the relative depth at which the tool is working. The control device positions a diverter valve to apply fluid power alternately between a depth positioning power cylinder and a pitch positioning power cylinder such that the attitude of the tool is automatically changed between a penetrating mode and a working mode at a preselected depth. A depth control circuit having a depth sensor and a depth selector which monitor the depth position of the tool in relation to a preselected depth and provide an output command when the tool is detected at the preselected depth. A pitch control circuit having a pitch sensor and a pitch selector which monitor the angular displacement of the tool and provide an output command at a preselected pitch. A control is connected to the depth and pitch control circuits and responsive to their commands to shift the position of the diverter valve and direct fluid power from the depth positioning cylinder to the pitch positioning cylinder when the tool is detected at a preselected depth and alternately shifts the diverter valve to redirect fluid power to the depth positioning cylinder when the tool is detected at a preselected pitch. The sensor generates a varying signal which is a function of tool position. The selector also generates an inverse reference signal which is a function of a position scale. These signals are compared by a bridge circuit including null detector.
Inventors
- 👤 Darrel M. Wooldridge
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 10:15
CPC Classifications
E; E02; E02F; E02F5/00; E02F5/30; E02F5/32; E02F9/00; E02F9/20; E02F9/2025; E02F9/2029; G; G05; G05D; G05D3/00; G05D3/12; G05D3/14; G05D3/1472
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
346 words
An improvement in a tractor mounted tool having a power operated tool positioning mount and a control circuit therefor which includes a depth control circuit having depth sensor means for detecting vertical displacement of the tool and generating an output signal in proportional relationship with the instantaneous position of the tool, a depth selector means connected in the depth control circuit with the depth sensor means and having means for displaying a preselected position setting of the tool and generating an output signal in proportional relationship with the preselected position, a pitch control circuit connected in the control circuit with the depth selector means, the pitch control circuit including a pitch sensor means for detecting angular displacement of the tool and generating an output signal in proportional relationship with the angular position of the tool, and a pitch selector means connected with the pitch sensor means, and control means connected in the circuit, the improvement comprising: the depth and pitch control circuits each being connected together and each including a bridge connected voltage divider with the sensor and selector means of each circuit being a part of the bridge connected voltage divider associated with said each circuit; and the control means including null means connecting said sensor and selector means in each of said depth and pitch control circuits forming a null detector between each of said voltage dividers, a depth relay connected to a depth null means and a pitch relay connected to a pitch null means, said depth relay being de-energized when the potential difference between the depth sensor and the depth selector is below a triggering voltage of said depth null means, said control means of said depth and pitch control circuits each generating a control output signal when the sensor means output signal correspondingly compares with the selector means output signal thereby denoting that the power operated tool is at a preselected position, said pitch circuit control means being connected with said depth circuit and initiating a change in pitch of the tool when the tool is detected at a preselected depth.
Claim 2
Dependent Claim
346 words
An improvement in a tractor mounted tool having a power operated tool positioning mount and a control circuit therefor which includes a depth control circuit having depth sensor means for detecting vertical displacement of the tool and generating an output signal in proportional relationship with the instantaneous position of the tool, a depth selector means connected in the depth control circuit with the depth sensor means and having means for displaying a preselected position setting of the tool and generating an output signal in proportional relationship with the preselected position, a pitch control circuit connected in the control circuit with the depth selector means, the pitch control circuit including a pitch sensor means for detecting angular displacement of the tool and generating an output signal in proportional relationship with the angular position of the tool, and a pitch selector means connected with the pitch sensor means, and control means connected in the circuit, the improvement comprising: the depth and pitch control circuits each being connected together and each including a bridge connected voltage divider with the sensor and selector means of each circuit being a part of the bridge connected voltage divider associated with said each circuit; and the control means including null means connecting said sensor and selector means in each of said depth and pitch control circuits forming a null detector between each of said voltage dividers, a depth relay connected to a depth null means and a pitch relay connected to a pitch null means, said depth relay being de-energized when the potential difference between the depth sensor and the depth selector is below a triggering voltage of said depth null means, said control means of said depth and pitch control circuits each generating a control output signal when the sensor means output signal correspondingly compares with the selector means output signal thereby denoting that the power operated tool is at a preselected position, said pitch circuit control means being connected with said depth circuit and initiating a change in pitch of the tool when the tool is detected at a preselected depth.
Claim 3
Dependent Claim
112 words
The device as defined in claim 1 and wherein said sensor means each include a variable potential device and is adapted to vary the strength of the output signal in relation to the instantaneous position of the tool, said selector means each including a variable potential device and is adapted to vary the strength of the output signal in relation to a scale denoting relative position settings, and said control means including a detector responsive to the relative strengths of the sensor and selector output signals and adapted to initiate a control output when the relative strengths of the sensor and selector output signals are detected to be within a specified range.
Claim 4
Dependent Claim
119 words
The device as defined in claim 2 and wherein said each sensor means includes an actuating member formed for relative movement depending on the position of said tool and adapted to vary the strength of the output signal in relation to the said position of the tool, and said each selector means includes a variable resistance and an actuating member which is movable to vary the strength of the output signal in relation to a scale denoting preselected positions of the tool, and said control means being responsive to the relative strengths of said sensor and selector output signals and adapted to initiate a control output when the sensor and selector output signals are substantially matched in relative strength.
Claim 5
Dependent Claim
78 words
The device as defined in claim 3 and wherein said variable resistance of said sensor means includes discrete resistance elements connected to provide an incremental linear potential varying device, said variable resistance of said selector means includes discrete resistance elements connected to provide an incremental linear potential varying device wherein, said output signals from said sensor means and selector means will be in discrete increments and provide precise differentiable potentials across said null detector of said control means.
Claim 6
Dependent Claim
184 words
The device as defined in claim 1 including an articulated tool mount for supporting and positioning a tool relative to a tractor, a depth positioning fluid operated cylinder operatively connected to said tool mount and formed for changing the vertical displacement of the tool, a pitch positioning fluid operated cylinder operatively connected to said tool mount and formed for changing the angular displacement of the tool, a fluid power circuit for selectively applying fluid power to the said fluid positioning cylinders and having a source of fluid power, a fluid control valve formed for selectively directing fluid power to either a first fluid conduit or a second fluid conduit, a diverter valve formed for selectively communicating the first and second conduits to the operatively ports of either the depth positioning cylinder or the ports of the pitch positioning cylinder, control means formed for positioning the diverter valve, said control means responsive to the control output of the depth control circuit wherein said diverter valve is positioned to direct fluid to the pitch positioning cylinder when the tool is detected at a specified vertical displacement.
Claim 7
Dependent Claim
45 words
The device as defined in claim 5 wherein said control means is responsive to the output of said pitch control circuit wherein said diverter valve is positioned to direct fluid to the depth positioning cylinder when the tool is detected at a specified angular displacement.
Claim 8
Dependent Claim
16 words
The improvement defined in claim 1 wherein said null means each includes a pair of transistors.
Claim 9
Dependent Claim
46 words
The improvement defined in claim 7 wherein said transistors are interconnected with said voltage dividers so that one of said transistors will be conducting when said potential difference is positive and the other one of said transistors will be conducting when said potential difference is negative.
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) | 1981-10-16 | 1982-04-17 | 1982-10-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1985-10-16 | 1986-04-17 | 1986-10-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1989-10-16 | 1990-04-17 | 1990-10-17 | $7700.00 | Window Closed / Lapsed |