Mark Roy Hoffman

Address:

250 E Pearson St, Chicago, IL 60611

VIN:

WP1AD2AP9ALA61913

Make:

Porsche

Model:

Cayenne

Year:

2010

Address:

2035 N Fremont St, Chicago, IL 60614

VIN:

WAUDF48H29K008830

Make:

AUDI

Model:

A4

Year:

2009

US Patent:

D622956, Sep 7, 2010

Filed:

Jan 29, 2010

Appl. No.:

29/354870

Inventors:

Mark R. Hoffman - Lake Forest IL, US

Assignee:

HD Electric Company - Waukegan IL

International Classification:

0301

US Classification:

D 3215

US Patent:

51306425, Jul 14, 1992

Filed:

Jun 13, 1991

Appl. No.:

7/714565

Inventors:

Mark R. Hoffman - Lake Forest IL
Niels C. Pedersen - Spring Grove IL

Assignee:

HD Electric Company - Deerfield IL

International Classification:

G01R 104
G01R 1104
H01R 1348
H01M 210

US Classification:

324127

Abstract:

The ammeter includes a tubular housing with a hook-shaped sensor secured thereto at one end thereof and coupled to battery-powered digital ammeter circuitry disposed within the housing. The other end of the housing is open and receives telescopically therein a cylindrical cartridge which includes either a cradle or a recess supporting a replaceable battery and carrying connectors for connecting the battery to the ammeter circuitry. A universal spline coupler is telescopically received in a bore in the cartridge and projects from the tubular housing when the cartridge is disposed therein for coupling to associated equipment, such as a hot stick.

US Patent:

52911241, Mar 1, 1994

Filed:

Jun 30, 1992

Appl. No.:

7/906694

Inventors:

Mark R. Hoffman - Lake Forest IL
Niels C. Pedersen - Hillsboro WI

Assignee:

HD Electric Company - Deerfield IL

International Classification:

G01R 3102
G01R 104

US Classification:

324 725

Abstract:

A tester applies a high-voltage test signal across the probes of a high-voltage measuring apparatus, wherein at least one of the probes is mounted at a probe end of an elongated insulated pole. The tester includes a battery-powered generator for generating the test signal which is applied across two contact terminals, respectively adapted for connection to the probes. One of the contact terminals is disposed at the bottom of an elongated tubular socket which receives the probe end of the pole, the contact terminal including two conductive members spring-biased apart until the pole is inserted in the socket. The generator is energized through a switch which may be mounted on the generator housing. In one embodiment the other contact terminal is an alligator clip and in a second embodiment the other contact terminal is disposed in a second socket.

US Patent:

61247146, Sep 26, 2000

Filed:

Mar 9, 1998

Appl. No.:

9/036772

Inventors:

William J. McNulty - River Forest IL
Mark R. Hoffman - Lake Forest IL

Assignee:

HD Electric Company - Waukegan IL

International Classification:

G01R 3102

US Classification:

324418

Abstract:

A lightning arrester tester includes two tubular poles respectively carrying probe terminals, one probe terminal being connected in series through a high-voltage rectifier and high-resistance circuit disposed within the pole to one terminal of a DC microammeter mounted on the outside of the one pole, the other probe terminal being connected through a high-resistance circuit housed within the second pole to the other meter terminal. A diode is connected in parallel with the meter to protect the meter from high leakage currents. In use, the probe terminals are respectively connected to a high-voltage power transmission or distribution line and one terminal of an arrester, the other terminal of which is grounded or, alternatively, to ground and to one terminal of an arrester, the other terminal of which is connected to a high-voltage power transmission or distribution line. The meter displays DC leakage current through the arrester.