Patents by Inventor Sheldon Chang

Sheldon Chang has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Patent number: 7074018
    Abstract: A ventricular assistive device (VAD) based on a progressive cavity pump includes a pump housing having an inlet and an outlet, a pump stator contained within the pump housing, a pump rotor rotatably disposed within the pump stator, a motor including a motor rotor contained within the pump housing and a direct drive means connected between the motor rotor and an axial shaft of the pump rotor for rotating the pump rotor. The motor rotates the motor rotor, which in turn rotates the pump rotor through the direct drive means. The rotation of the pump rotor within the pump stator forms a plurality of cavities that carry blood forward through the pump housing from the inlet to the outlet as the motor drives the direct drive means.
    Type: Grant
    Filed: July 10, 2003
    Date of Patent: July 11, 2006
    Inventor: Sheldon Chang
  • Publication number: 20060089521
    Abstract: A rotor driven linear flow blood pump (LFBP) which completely separates the driving motor from the pumped blood is used as a vascular assist device (VAD). Without the possible hazard of blood contamination, a brushless d. c. motor (BLDC) is ideal to drive and to control the LFBP. Thus we have the best of two worlds: For patient mobility, d. c. batteries are the best as a VAD energy source, and LFBP provides the most means at a physician's disposal for curing his patient with a severely damaged heart. A key to success in making the above possible is a new concept of surface affinity. Complete blood containment is made possible by using a material with zero surface affinity with blood as the bearing material throughout.
    Type: Application
    Filed: October 21, 2004
    Publication date: April 27, 2006
    Inventor: Sheldon Chang
  • Publication number: 20050008509
    Abstract: A ventricular assistive device (VAD) based on a progressive cavity pump includes a pump housing having an inlet and an outlet, a pump stator contained within the pump housing, a pump rotor rotatably disposed within the pump stator, a motor including a motor rotor contained within the pump housing and a direct drive means connected between the motor rotor and an axial shaft of the pump rotor for rotating the pump rotor. The motor rotates the motor rotor, which in turn rotates the pump rotor through the direct drive means. The rotation of the pump rotor within the pump stator forms a plurality of cavities that carry blood forward through the pump housing from the inlet to the outlet as the motor drives the direct drive means.
    Type: Application
    Filed: July 10, 2003
    Publication date: January 13, 2005
    Inventor: Sheldon Chang
  • Patent number: 6305110
    Abstract: A modular neon sign control system with a plurality of discrete neon letters, numbers or symbols, each with plugs to plug into at any place along a continuous electrical rail. Each neon letter, etc. is a single tube having its own driving inverter and digital decoder. Dip switches set a unique digital code into the decoder for each letter. A programmed memory controls a system encoder which sends coded signals to each decoder to compare with each letter's unique code. Those letters receiving the matching digital signals are activated or deactivated according to the program. The letters, etc. of the sign can be operated simultaneously, serially, randomly, in a pattern, or in a flashing manner. Power from an ac adapter is supplied along with the signals from the encoder to the electrical rail, and the decoder separates the power from the coded signals. The letters may be individually and easily prearranged and substituted in a sign.
    Type: Grant
    Filed: November 13, 1998
    Date of Patent: October 23, 2001
    Inventor: Sheldon Chang
  • Patent number: 5019764
    Abstract: A lightweight hand-held scanning device for repetitively scanning a laser light source having a laser light generating means and at least one high speed scanning motor controlled by a resonant motor circuit which automatically controls the frequency and amplitude of oscillation of a high speed scanning motor. The frequency and amplitude control is accomplished by using a single feedback signal obtained from the windings of the motor which indicates resonance and which also measures the amplitude of oscillation. The feedback signal obtained is a second harmonic of the driving current. The circuit can be utilized to tune and maintain the motor in a resonant oscillating mode. By controlling both the frequency and amplitude of oscillation the high speed scanning motor can maintain a consistent scanning speed and use less power.
    Type: Grant
    Filed: March 13, 1989
    Date of Patent: May 28, 1991
    Assignee: Symbol Technologies, Inc.
    Inventor: Sheldon Chang