Inventor

Dick J. Kolkman

Inventor

Gibsonia, PA, US

Overview

5→

Patents

1977–2000

Patent span

Electricity

Primary field (CPC H)

Patents· 5 as inventor

Public. Assignee & technology derived from the patent record. Each patent links to its LexDana page.

B61Lprimary

B61LGuiding railway traffic30%

H01HElectric switches10%

H02JElectric power networks10%

H02MApparatus for conversion between ac and ac, between ac and dc, or between dc and dc, and for use with mains or similar power supply systems10%

H03KPulse technique10%

H04LTransmission of digital information, e.g. telegraphic communication10%

Y02BClimate change mitigation technologies related to buildings, e.g. housing, house appliances or related end-user applications10%

Y04SSystems integrating technologies related to power network operation, communication or information technologies for improving the electrical power generation, transmission, distribution, management or usage, i.e. smart grids10%

PatentTitleYear

6,052,050'Two-wire signal transmitter and method for maintaining integrity of electrical contacts'2000 4,652,986'Vital inverter driver'1987 4,645,148'Fail-safe voltage-limiting circuit for an audio frequency overlay track circuit'1987 4,099,692'Transfer apparatus for energy sources'1978 4,059,845'Fail-safe time delay circuit'1977

Career & activity timeline

Assembled from patent assignee/location history and declaration credentials.

1977–1978Patents assigned to WESTINGHOUSE AIR BRAKE CO (2)· patent assignee history

1977–1987Based in Gibsonia, PA, US· patent location history

1987Patents assigned to AMERICAN STANDARD INC (2)· patent assignee history

2000Patents assigned to UNION SWITCH & SIGNAL INC (1)· patent assignee history

2000Based in Penn Hills Township, Allegheny County, PA, US· patent location history

Inventor activity

Assignee and location history derived from the patent record.

Assignees

Assignee	Patents	Span
AMERICAN STANDARD INC	2	1987
WESTINGHOUSE AIR BRAKE CO	2	1977–1978
UNION SWITCH & SIGNAL INC	1	2000

Locations

Location	Patents	Span
Gibsonia, Pennsylvania, US	4	1977–1987
Penn Hills Township, Allegheny County, Pennsylvania, US	1	2000