David D Chang

US Patent:

6538595, Mar 25, 2003

Filed:

Jan 26, 2000

Appl. No.:

09/491561

Inventors:

John R. Tucker - Canton GA
David I. Chang - Norcross GA
William L. Lott - Duluth GA

Assignee:

Scientific-Atlanta, Inc. - Lawrenceville GA

International Classification:

G08C 1912

US Classification:

341178, 341 29, 345168, 710 6

Abstract:

An infrared (IR) keyboard having a communication protocol and a method for operating same includes circuitry for converting a standard recognized keystroke into a corresponding IR data word for transmission to an IR receiver. The IR keyboard includes circuitry and logic which determines the type of key being actuated and assigns a communication protocol based upon the detected key. An IR code word corresponding to the detected key is associated with the key press and is transmitted from the IR keyboard to an IR receiver using a protocol corresponding to the type of key detected.

US Patent:

6988471, Jan 24, 2006

Filed:

Dec 23, 2003

Appl. No.:

10/743000

Inventors:

David Yu-Zhang Chang - Lawrenceville GA, US

Assignee:

Caterpillar Inc - Peoria IL

International Classification:

F01L 9/02

US Classification:

123 9012, 123 9015, 123198 F, 91407, 91408

Abstract:

An engine valve actuation system includes an engine valve moveable between first and second positions, a valve actuation assembly connected to move the engine valve between the first and second positions, a fluid actuator configured to selectively modify a timing of the engine valve in moving from the second to the first position, a source of fluid, and a pair of passages in the cylinder that allow fluid to flow from the chamber to the fluid source. The fluid actuator includes a cylinder and a piston at least partly defining a chamber. The piston is slidably movable in the cylinder between a first position and a second position, and blocks at least a portion of one of the passages at an intermediate position between the second position and the first position to reduce fluid flow from the chamber when the piston moves from the second position toward the first position.

US Patent:

6997148, Feb 14, 2006

Filed:

Oct 15, 2004

Appl. No.:

10/966901

Inventors:

David Yu-Zhang Chang - Lawrenceville GA, US

Assignee:

Caterpillar Inc. - Peoria IL

International Classification:

F01L 9/02

US Classification:

123 9012, 123 9015, 123 9016, 123 9063, 123198 F, 251101, 251102, 92 136, 92 138

Abstract:

An engine valve actuator for an internal combustion engine is provided. The actuator includes a housing having an opening. An adjustment member is disposed in the housing and defines a fluid chamber having a chamber wall. A piston is also disposed in the opening. The piston defines a piston chamber and has a pressure surface, a protrusion extending from the pressure surface, and a groove disposed in the pressure surface surrounding the protrusion and in fluid communication with the piston chamber. A fluid passageway is adapted to controllably communicate pressurized fluid to the housing opening. A push rod is operatively engageable with the piston and is adapted to controllably actuate an engine valve of the engine.

US Patent:

7228826, Jun 12, 2007

Filed:

Aug 26, 2004

Appl. No.:

10/926496

Inventors:

David Yu-Zhang Chang - Lawrenceville GA, US

Assignee:

Caterpillar Inc - Peoria IL

International Classification:

F01L 9/02

US Classification:

123 9012, 123 9013, 251 12

Abstract:

The present disclosure provides an engine having a gas exchange valve and an actuator for the gas exchange valve, and also a method of reducing valve seating impact velocity. The actuator includes a body having a fluid inlet and a fluid outlet. A plunger is reciprocable in the body and has a travel distance between an advanced position and a retracted position, the plunger and body defining a chamber. A flow restriction orifice is disposed in at least one of the plunger and the body, and the chamber is in unrestricted fluid communication with the outlet over a first portion of the travel distance and in restricted fluid communication with the outlet by way of the orifice over at least a second portion of the travel distance.

US Patent:

7318398, Jan 15, 2008

Filed:

Aug 15, 2003

Appl. No.:

10/641115

Inventors:

David Yu-Zhang Chang - Lawrenceville GA, US

Assignee:

Caterpillar Inc. - Peoria IL

International Classification:

F01L 9/02

US Classification:

123 9012, 123 9015, 123 9016

Abstract:

An engine valve actuation system includes an engine valve moveable between a first position that blocks a flow of fluid and a second position that allows a flow of fluid. The system also includes a valve actuation assembly connected to move the engine valve between the first position and the second position and a fluid actuator configured to selectively modify a timing of the engine valve in moving from the second position to the first position. The fluid actuator includes a first piston. The system further includes an accumulator including a second piston, wherein the second piston is slidably movable in the first piston.

US Patent:

20050284431, Dec 29, 2005

Filed:

Jun 7, 2005

Appl. No.:

11/146281

Inventors:

David Chang - Lawrenceville GA, US

International Classification:

F01L009/02

US Classification:

123090130

Abstract:

An engine valve actuation system includes an engine valve moveable between first and second positions, a valve actuation assembly connected to move the engine valve between the first and second positions, a fluid actuator configured to selectively modify a timing of the engine valve in moving from the second to the first position, a source of fluid, and a pair of passages in the cylinder that allow fluid to flow from the chamber to the fluid source. The fluid actuator includes a cylinder and a piston at least partly defining a chamber. The piston is slidably movable in the cylinder between a first position and a second position, and blocks at least a portion of one of the passages at an intermediate position between the second position and the first position to reduce fluid flow from the chamber when the piston moves from the second position toward the first position.

US Patent:

D3735885, Sep 10, 1996

Filed:

Jun 29, 1995

Appl. No.:

D/040884

Inventors:

Donald H. Bowen - Lilburn GA
David I. Chang - Duluth GA
Bryce G. Rutter - St. Louis MO
Michael D. Prstojevich - St. Louis MO
Robert T. Van Orden - Norcross GA
Charles K. Fincher - Marietta GA

Assignee:

Scientific-Atlanta, Inc. - Norcross GA

US Classification:

D14218

US Patent:

D4210166, Feb 22, 2000

Filed:

Dec 13, 1997

Appl. No.:

D/083107

Inventors:

Donald H. Bowen - Lilburn GA
David I. Chang - Norcross GA
John R. Tucker - Canton GA

Assignee:

Scientific-Atlanta, Inc. - Norcross GA

International Classification:

1403

US Classification:

D14218