Patents Represented by Attorney Robert L. Marben
  • Patent number: 4912488
    Abstract: Camera apparatus including a housing within which an exposure station is provided with a film handling means provided at the exposure station for supporting and disposing a strip of film and a linear array of electric-to-light transducers disposed to direct light from the array to the strip of film as it is moved past the exposure station. Another embodiment employs two linear arrays of electric-to-light transducers which are used to expose separate areas of the film as it is moved past the exposure station.
    Type: Grant
    Filed: July 1, 1988
    Date of Patent: March 27, 1990
    Assignee: Minnesota Mining and Manufacturing Company
    Inventors: Robert S. Berglund, Earl K. Hoyne
  • Patent number: 4897555
    Abstract: A current split circuit that includes a multiplying digital to analog converter (DAC) and a controller. The controller establishes a first and second terminal of the DAC at the same potential so that a digital input to the DAC determines the ratio by which a current at a third terminal of the DAC is split between the first and second terminals of the DAC.
    Type: Grant
    Filed: November 23, 1988
    Date of Patent: January 30, 1990
    Assignee: Minnesota Mining and Manufacturing Company
    Inventor: Eric L. Reed
  • Patent number: 4873533
    Abstract: A marker for positioning near a buried object wherein the marker can be detected to locate the buried object. The marker includes a passive resonant type antenna which becomes inoperative when the initial position for the buried marker is changed. A lead wire and/or a mercury switch that is a part of the antenna serve to make the antenna inoperative due to such change in the initial position of the marker.
    Type: Grant
    Filed: October 9, 1987
    Date of Patent: October 10, 1989
    Assignee: Minnesota Mining and Manufacturing Company
    Inventor: Tomoyasu Oike
  • Patent number: 4868507
    Abstract: A resistance fault locator circuit having a digitally controlled current split circuit, an error amplifier and a programmed microcomputer plus a switching means for establishing several modes of operation of the circuit for determining the distance to a fault between two conductors of a cable.
    Type: Grant
    Filed: November 23, 1988
    Date of Patent: September 19, 1989
    Assignee: Minnesota Mining and Manufacturing Company
    Inventor: Eric L. Reed
  • Patent number: 4866388
    Abstract: A method and system for determining the location of a first insulated conductor and a plurality of similar branch conductors that are branches of the first conductor, but without ohmic contact being made with the first conductors. A passive marker having a resonant circuit that includes an inductor and capacitor is provided for each of the branch conductors and is positioned to be inductively coupled to the first conductor and the associated branch conductor. The first conductor is a part of a closed loop circuit and each branch conductor is a part of separate closed loop circuits. An alternating signal applied to any one of the closed loop circuits is inductively transmitted to each of the other closed loops that is inductively coupled to a passive marker having a resonant frequency equal to the frequency of the alternating signal.
    Type: Grant
    Filed: May 11, 1988
    Date of Patent: September 12, 1989
    Assignee: Minnesota Mining and Manufacturing Company
    Inventors: Armond D. Cosman, Joe T. Minarovic
  • Patent number: 4816642
    Abstract: A hot melt adhesive applicator operable at a number of selected temperatures having a portion of the circuitry for control of the applicator temperature at a point remote from the applicator body. The remotely located circuitry employs a differential amplifier and a zero crossing detector for controlling the operation of a triac which, when turned on, increases the temperature at the applicator. The operational amplifier is protected by a clamping circuit from receiving a signal, when a temperature setting is changed from a high to a low setting, that would otherwise cause the differential amplifier to provide an output required for turning on the triac which would cause a run away condition to exist.
    Type: Grant
    Filed: June 26, 1987
    Date of Patent: March 28, 1989
    Assignee: Minnesota Mining and Manufacturing Company
    Inventor: Richard L. Dennison
  • Patent number: 4794632
    Abstract: Telephone trunk line testing circuitry for connection to a private branch exchange (PBX) and the telephone trunk lines for the PBX including a microcomputer unit (MCU), switching circuitry, a DTMF receiver, and a tone generator for connecting one of the trunk lines as a control trunk for the circuitry. Under the control of the MCU programmed to respond to DTMF various signal commands sent from a telephone at the far end of the control trunk the circuitry operates to selectively disconnect (isolating) one of the other trunks at a time from the PBX and connect it to the circuitry with the circuitry configured under control of the MCU for completing various test involving the trunk under test (TUT), control trunk, switching circuitry and the tone generator, including the supply of tone signals from the tone generator during some of the test configurations.
    Type: Grant
    Filed: May 20, 1987
    Date of Patent: December 27, 1988
    Assignee: Minnesota Mining and Manufacturing Company
    Inventors: Peter G. Burton, James K. Kennedy
  • Patent number: 4767237
    Abstract: A marking tape that is positioned underground above utility lines wherein the marking tape carries a pair of closely spaced, parallel, insulated conductors that extend the length of the tape and at least one other insulated conductor extending the length of the tape which is separated from the pair of conductors at a distance that is greater than the distance between the conductors of the pair of conductors. Passive markers having a resonant circuit can be selectively placed along the tape wherein the resonant circuit is electromagnetically coupled to the pair of conductors and the other conductor. The other insulated conductor can be one of a pair of conductors similar to the other pair of conductors. A method is disclosed whereby the making tape can be electromagnetically traced with the position of the passive markers established. A method is also disclosed for determining the distance to a break in the tape which causes the pair of conductors to be severed.
    Type: Grant
    Filed: February 8, 1988
    Date of Patent: August 30, 1988
    Assignee: Minnesota Mining and Manufacturing Company
    Inventors: Armond D. Cosman, Joe T. Minarovic
  • Patent number: 4761656
    Abstract: A passive marker device including a tuned circuit enclosed in a housing which includes a base member with an upstanding rim with a cover member bonded to the rim and to a central portion of the base member. An opening is provided that extends through the housing at the central portion of the housing. A boss extends from the central portion of the base member to the cover member. The boss is recessed on the side of the base member that is away from the cover.
    Type: Grant
    Filed: May 23, 1986
    Date of Patent: August 2, 1988
    Assignee: Minnesota Mining and Manufacturing Company
    Inventors: Armond D. Cosman, Larry R. Cox
  • Patent number: 4761660
    Abstract: A laser scanner apparatus using a laser reference beam that is directed to and scans a grating plate which is used for producing a data clock for the apparatus. The grating plate has a line grating formed by a plurality of lines that are equally spaced along the scan of the grating plate by the laser reference beam. The plurality of lines, if extended, intersect at a single point. The grating plate can have more than one such line grating.
    Type: Grant
    Filed: December 15, 1986
    Date of Patent: August 2, 1988
    Assignee: Minnesota Mining and Manufacturing Company
    Inventor: Charles C. Lee
  • Patent number: 4734881
    Abstract: Circuitry for the validation of repetitive signals including input/output circuitry providing information regarding signals received that is connected to a progammable microprocessor, a read only memory and random access memory. The microprocessor is programmed so the circuitry determines the receipt of an input signal at any one of several signal inputs. When a first signal is received at one of the signal inputs a "lock-out" time interval is provided during which another signal cannot be received at any signal input. This is followed by a "window" time interval during which another input signal can be received at the signal input receiving the first signal. A "lock-out" and a "window" time interval are provided for each signal received at the signal input during a "window" time period at which the first input signal was received. Such signals are counted until a predetermined count is reached thereby establishing the received signals as valid signals.
    Type: Grant
    Filed: February 18, 1986
    Date of Patent: March 29, 1988
    Assignee: Minnesota Mining and Manufacturing Company
    Inventors: Theodore D. Klein, Michael R. Oran
  • Patent number: 4730603
    Abstract: An improvement to an implantable amplitude modulated frequency receiver wherein a resistor in the demodulator portion of a prior art receiver, which provides a discharge path for a capacitor, is replaced with an active circuit portion that includes a semiconductor device that provides the discharge path wherein the conductivity level of the semiconductor device is inversely related to the level of conduction of a rectifier to which the received amplitude modulated signal is applied. The active circuit portion improves the efficiency of the receiver in that less power is lost than in the case of the resistor the active circuit portion replaces.
    Type: Grant
    Filed: January 28, 1987
    Date of Patent: March 15, 1988
    Assignee: Minnesota Mining and Manufacturing Company
    Inventor: Robert J. Fretz
  • Patent number: 4711566
    Abstract: Apparatus using a single document transport means for microfilming the document and scanning the document for obtaining digital signals for storage that are indicative of the image carried on the document. One embodiment provides for sequential presentment of the document for filming and scanning. Another embodiment provides for simultaneous filming and scanning. Circuitry is disclosed by which the digital signals are processed for use in controlling the light source used for filming of the document. Circuitry is disclosed for supplying information for later retrieval of the digital signals and/or the microfilm for a particular document.
    Type: Grant
    Filed: October 31, 1985
    Date of Patent: December 8, 1987
    Assignee: Minnesota Mining and Manufacturing Company
    Inventor: Bruce M. Evans
  • Patent number: 4712094
    Abstract: A passive marker including a tuned circuit having an inductance and a capacitance carried by a carrier enclosed within a hollow sphere that is partially filled with a liquid to freely float the carrier. The inductance includes a coil which, when the carrier is floating, positions the axis of the coil so it is closer to the vertical than the horizontal. The passive marker is of a type that is buried relative to portions of utilities such as gas, telephone, water and power lines, for use in locating such portions when necessary.
    Type: Grant
    Filed: May 29, 1986
    Date of Patent: December 8, 1987
    Assignee: Minnesota Mining and Manufacturing Company
    Inventor: John H. Bolson, Sr.
  • Patent number: 4706293
    Abstract: Circuitry usable in a tamper protected recording system for characterizing audio signals at the time of recording including a filter for selecting a portion of the audio signal, a zero crossing detector to detect zero crossings, a threshold detector to determine when the threshold of the detector is satisfied, a first microprocessor for counting the zero crossing detections for successive time intervals and determining for each of the time intervals whether the threshold was satisfied and a second microprocessor for converting the counts and threshold information into data signals that can be recorded with the audio signal.
    Type: Grant
    Filed: August 10, 1984
    Date of Patent: November 10, 1987
    Assignee: Minnesota Mining and Manufacturing Company
    Inventor: Michael J. Knowd
  • Patent number: 4706282
    Abstract: An improved decoder for a recorder-decoder system wherein a threshold level detector is included in the decoder. The recorder provides for the recording of an audio signal plus a data signal. The data signal includes zero crossing information for sequential increments of time plus an indication of whether the threshold level was met for an increment of the recorded audio. Upon playback the decoder also provides a data signal based on the recorded audio. The threshold level detector of the decoder is higher than that of the recorder. If the recorded data signal indicates the threshold was not met and the same threshold indication is not provided by the threshold level detector of the decorder for the corresponding increment of the recorded audio signal, tampering of such audio increment of the recorded audio is considered to have occurred.
    Type: Grant
    Filed: December 23, 1985
    Date of Patent: November 10, 1987
    Assignee: Minnesota Mining and Manufacturing Company
    Inventor: Michael J. Knowd
  • Patent number: 4683551
    Abstract: Random access memory (RAM) clock switching circuitry for a laser printer having a RAM for storage of microprocessor information plus storage of font information with separate clock generators is provided for use in accessing the two types of information. The switching circuitry has a switch portion for alternately connecting the clock generators to a lockout circuit portion. A lockout request signal from the laser printer microprocessor determines when clock pulses presented to the lockout circuit can be applied to the RAM.
    Type: Grant
    Filed: March 28, 1984
    Date of Patent: July 28, 1987
    Assignee: Minnesota Mining and Manufacturing Company
    Inventor: David J. Schoon
  • Patent number: 4668851
    Abstract: A circuit arrangement for control of the temperature of a heating element adapted for contact by a material to be heated includes a transformer wherein the secondary winding is a metal ring which is the heating element with a temperature detection winding provided on the core of the transformer. An electronic switch and current sensing means are connected to the primary. A comparator, which receives input signals from the current sensing means and temperature detection winding, is operatively connected to the electronic switch to control its operation.
    Type: Grant
    Filed: September 6, 1985
    Date of Patent: May 26, 1987
    Assignee: Minnesota Mining and Manufacturing Company
    Inventor: Anton K/u/ pper
  • Patent number: 4660968
    Abstract: An exposure control for an imaging apparatus, the apparatus producing a light image based on an image member presented to the apparatus which is directed to a light responsive member via a partially silvered mirror of the apparatus. The exposure control includes a photocell which receives light transmitted through the mirror via a condensing lens, the photocell being connected to a circuit means which produces a signal having a duration, which varies according to the resistance of the photocell. The signal is used by a portion of the circuit means for controlling the exposure of the light responsive member to the light image.
    Type: Grant
    Filed: April 9, 1985
    Date of Patent: April 28, 1987
    Assignee: Minnesota Mining and Manufacturing Company
    Inventor: Arnold J. Alderman
  • Patent number: 4649402
    Abstract: An electrographic stylus recording apparatus producing a toner powder image on a receptor belt wherein non-imaging toner powder is collected at a cylindrical sleeve located downstream from the stylus array and is subsequently returned from the cylindrical sleeve to the upstream side of the stylus array by depositing toner powder from the cylindrical sleeve onto the receptor belt by adjustment of the toner powder on the cylindrical sleeve relative to the space between the cylindrical sleeve plus the application of a d.c. voltage to the cylindrical sleeve.
    Type: Grant
    Filed: March 7, 1986
    Date of Patent: March 10, 1987
    Assignee: Minnesota Mining and Manufacturing Company
    Inventors: George G. Lunde, Earl K. Hoyne, Charles K. Nordeen