Patent US3576991A successfully refreshed from Google Patents.
US3576991A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Track circuit pickup unit
Assignee: Marquardt Industrial Products Co
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Filing: 1969-01-23
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Granted: 1971-05-04
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Expires: 1989-01-23
Abstract
Abstract Apparatus is described which detects the presence of a train within a given area. The apparatus includes a sensing unit which comprises an iron core transformer vertically positioned between the rails of a railroad track. A single-loop primary winding is coupled across the track. A secondary winding of the transformer is coupled to a receiver. At least one transmitter is coupled to the track at a predetermined distance from the sensing unit. The receiver detects secondary voltage induced by the track voltage applied to the primary winding. The wheel and axle of the train, when approaching the given area between the selected transmitter and the receiver, from the receiver end causes current to flow in the rails past the sensing unit, which through magnetic flux coupling to the sensing device adds in polarity to the magnetic flux in the core due to the primary winding, thereby increasing the signal induced into the secondary winding. This signal is detected by the receiver. When the train is within the given area between the selected transmitter and the receiver, the wheels and axle act as a shunt to short out any signals from the desired transmitter to the pickup unit.
Inventors
- 👤 Harlan J Wilson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 18:47
CPC Classifications
B; B61; B61L; B61L1/00; B61L1/18; B61L1/181; B61L1/187
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
124 words
In combination with a railroad track including a pair of rails: a transmitter coupled to said pair of rails of said track and adapted to apply electrical energy to said rails; a pickup unit positioned between said pair of rails of said track, said pickup unit including a first transformer including a winding being adapted to inductively receive electrical energy from said rails, a second transformer having a first winding being directly coupled to the rails of said track and a second winding being inductively coupled to said first winding and being coupled in parallel with the winding of said first transformer; and a receiver responsive to said pickup unit and being coupled to the said first and second transformer of said pickup unit.
Claim 2
Dependent Claim
124 words
In combination with a railroad track including a pair of rails: a transmitter coupled to said pair of rails of said track and adapted to apply electrical energy to said rails; a pickup unit positioned between said pair of rails of said track, said pickup unit including a first transformer including a winding being adapted to inductively receive electrical energy from said rails, a second transformer having a first winding being directly coupled to the rails of said track and a second winding being inductively coupled to said first winding and being coupled in parallel with the winding of said first transformer; and a receiver responsive to said pickup unit and being coupled to the said first and second transformer of said pickup unit.
Claim 3
Dependent Claim
65 words
The combination, as defined in claim 1, and further comprising: a first resistor coupled in series with one output lead of the second winding of said second transformer; and a second resistor coupled in series with one output lead of the winding of first transformer of said pickup unit and to the output lead of said winding of said second transformer containing said first resistor.
Claim 4
Dependent Claim
169 words
In combination with a railway track including a pair of rails: a first transmitter coupled to said pair of rails of said track; a first pickup unit positioned between said pair of rails of said track, said pickup unit including a high permeability core transformer having a pickup winding, said pickup winding being coupled to rails of said track; a receiver responsive to said pickup unit and being coupled to the pickup winding of the transformer of said first pickup unit; a second pickup unit positioned between said pair of rails of said track and between said first pickup unit and said first transmitter, said second pickup unit including a high permeability core transformer having a pickup winding, said pickup winding being inductively coupled to the rails of said track; and a booster amplifier, said booster amplifier being coupled to the pickup winding of said second pickup unit and including a pair of output leads coupled to said rails between said first pickup unit and said second pickup unit.
Claim 5
Dependent Claim
169 words
In combination with a railway track including a pair of rails: a first transmitter coupled to said pair of rails of said track; a first pickup unit positioned between said pair of rails of said track, said pickup unit including a high permeability core transformer having a pickup winding, said pickup winding being coupled to rails of said track; a receiver responsive to said pickup unit and being coupled to the pickup winding of the transformer of said first pickup unit; a second pickup unit positioned between said pair of rails of said track and between said first pickup unit and said first transmitter, said second pickup unit including a high permeability core transformer having a pickup winding, said pickup winding being inductively coupled to the rails of said track; and a booster amplifier, said booster amplifier being coupled to the pickup winding of said second pickup unit and including a pair of output leads coupled to said rails between said first pickup unit and said second pickup unit.
Claim 6
Dependent Claim
106 words
A presence detector used with a railway and including at least a pair of rails comprising: means for providiNg a magnetic field around said rails and normal to the longitudinal axis of said rails; a first inductance means positioned substantially between said rails and said inductance means including a magnetic core having a magnetic axis being normal to the plane of the rails, a first coil coupled to said rails and around said core, and a second coil coupled around said core; and means coupled to said inductance means to detect changes in magnetic flux created in said rails by the presence of a shunt thereacross.
Claim 7
Dependent Claim
106 words
A presence detector used with a railway and including at least a pair of rails comprising: means for providiNg a magnetic field around said rails and normal to the longitudinal axis of said rails; a first inductance means positioned substantially between said rails and said inductance means including a magnetic core having a magnetic axis being normal to the plane of the rails, a first coil coupled to said rails and around said core, and a second coil coupled around said core; and means coupled to said inductance means to detect changes in magnetic flux created in said rails by the presence of a shunt thereacross.
Claim 8
Dependent Claim
32 words
A presence detector, as defined in claim 4, wherein said first coil comprises a single turn of wire and said second coil comprises a plurality of turns of wire around said core.
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) | 1974-05-03 | 1974-11-02 | 1975-05-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-05-03 | 1978-11-02 | 1979-05-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-05-03 | 1982-11-02 | 1983-05-04 | $7700.00 | Window Closed / Lapsed |