Patents Assigned to Danfoss
  • Heating installation with heat pump
    Patent number: 4576332
    Abstract: The invention relates to a heating installation of the type having a heat pump, radiators having valves, and a control device having a desired value generator for controlling the upstream temperature that delivers as an effective desired value, a guided desired value guided by guide parameters such as the external temperature and/or a reference room temperature. The invention involves providing a heating installation of the aforementioned kind in which the efficiency and life of the heat pump are improved. Pursuant to this objective the control device has a comparator which compares the guided desired value with a variable limiting value higher then the downstream temperature by a predetermined temperature difference and the desired value generator reduces the effective desired value at least down to the variable limiting value when the latter is exceeded by the guided desired value.
    Type: Grant
    Filed: February 19, 1985
    Date of Patent: March 18, 1986
    Assignee: Danfoss A/S
    Inventors: Poul Neldeberg, Steen H. Olsen
  • Apparatus for securing a manually operable setting element against rotation
    Patent number: 4574831
    Abstract: The invention relates to a security device which discourages tampering with the operating or control element of a manually settable device of the type which has a window through which the control element is accessed. The security device has the form of a strap which surrounds the housing of the manually settable device and covers the access window. The ends of the strap are permanently connected such that the strap would have to be destroyed to be removed.
    Type: Grant
    Filed: March 11, 1983
    Date of Patent: March 11, 1986
    Assignee: Danfoss A/S
    Inventor: Peter E. Jacobsen
  • Snap switch
    Patent number: 4575596
    Abstract: The invention relates to a toggle type snap switch having an operating arm and a switching arm with a toggle spring hingedly connected between these arms. In one embodiment of the invention the toggle spring is in the form of a plate with a window in one end thereof. The switching arm has separate, relatively moveable snap arm and switching arm sections and a hinge connection is provided between the toggle spring and the switching arm section. The window in the toggle spring has upper and lower edges alternately abuttingly engageable with the free end of the snap arm section for opposite snap positions of the operating arm. The window may have laterally extended slot sections to form a part of the hinge connection between the toggle spring and the switching arm section.
    Type: Grant
    Filed: November 26, 1984
    Date of Patent: March 11, 1986
    Assignee: Danfoss A/S
    Inventors: Niels P. Thorsen, Per Andersen
  • Hydrostatic control device, particularly steering device
    Patent number: 4575321
    Abstract: The invention relates to a hydrostatic steering control device of the type having two motor ports connectable to a servomotor and a metering unit for metering the flow of fluid to or from the servomotor in accordance with the rotational movement of a steering wheel for operating the control device. The invention is directed to a way of balancing the distributing valve of the control device by subjecting opposite sides thereof to high and intermediate pressure zones and providing a throttle gap between the high and intermediate pressure zones and a second oppositely acting throttle gap between the intermediate pressure zone and a third zone of lower pressure.
    Type: Grant
    Filed: July 19, 1985
    Date of Patent: March 11, 1986
    Assignee: Danfoss A/S
    Inventors: Hans C. Petersen, Erik Kyster, Svend E. Thomsen
  • Refrigeration compressor having a tubular insert of thermally insulating material in suction passage
    Patent number: 4573881
    Abstract: The invention relates to an encapsulated motor-compressor unit for a refrigerator. The unit includes a capsule in which is resiliently mounted a combined or integrated motor and compressor having a common housing casting. The housing casting defines a cylinder for receiving a piston and a sound damping chamber. The housing casting has pressure and suction chambers at one end thereof and a suction passage which extends from the sound damping chamber to the suction chamber. The efficiency of the unit is improved by providing a tubular insert of thermally insulating material in the suction passage to reduce the transfer of heat from the compressor cylinder to the inlet gas in the suction passage.
    Type: Grant
    Filed: May 20, 1985
    Date of Patent: March 4, 1986
    Assignee: Danfoss A/S
    Inventor: Bendt W. Romer
  • Current supply apparatus for an A.C. consumer
    Patent number: 4574341
    Abstract: The invention relates to a current supply apparatus in which galvanic separation between the control portion and the high voltage portion is provided and has the feature of a rapid interruption of an overcurrent upon overload, such as, short-circuiting. Control pulses for the chopper and inverter transistor thereof are fed to a base control circuit by way of an opto-coupler and the gate feedable with an appropriate blocking signal on overcurrent is disposed between the opto-coupler and the base control circuit for the chopper and for the transistor of the inverter that are connected to the current return line of the inverter.
    Type: Grant
    Filed: November 25, 1983
    Date of Patent: March 4, 1986
    Assignee: Danfoss A/S
    Inventors: Kjeld Hellegaard, Hans Doktor
  • Low power loss snubber for switching power transistors
    Patent number: 4572969
    Abstract: The invention relates to an electronic switching circuit having a power transistor controlled by a control stage. During the "on" time for the transistor a capacitor of a switch off relief circuit is charged and at "turn-off" time the capacitor is discharged through the base-emitter path of the power transistor. The charge of the capacitor is thus utilized to produce a strong base current surge during switching on of the power transistor so as to operate the power transistor rapidly and thereby reduce the power loss of its switching path.
    Type: Grant
    Filed: October 3, 1983
    Date of Patent: February 25, 1986
    Assignee: Danfoss A/S
    Inventors: Kjeld Hellegaard, Hans Doktor, Niels O. Jacobsen
  • Hydraulic control apparatus for a servo-motor, particularly for vehicle steering
    Patent number: 4566272
    Abstract: The invention relates to a hydrostatic steering control unit of the type having a metering motor for supplying metered pressurized fluid to external servomotor. The unit has a throttled controlled passage which bypasses the metering motor and has a flow therethrough which has a definite relationship to the flow through the metering motor. In this way a comparatively large amount of pressure fluid can be supplied to the servomotor even though the flow capacity of the metering motor is much smaller.
    Type: Grant
    Filed: December 8, 1983
    Date of Patent: January 28, 1986
    Assignee: Danfoss A/S
    Inventors: Hans C. Petersen, Erik Kyster
  • Saturation control of a switching transistor
    Patent number: 4564769
    Abstract: The invention relates to a base control circuit for a switching transistor in which diodes are utilized to maintain the base-emitter voltage at a higher level than the collector-emitter voltage, upon the turn-on voltage being applied, to minimize switching-on losses while operating to avoid saturation.
    Type: Grant
    Filed: September 12, 1983
    Date of Patent: January 14, 1986
    Assignee: Danfoss A/S
    Inventor: Anna Melamed
  • Hydraulic actuator for control of valves
    Patent number: 4563941
    Abstract: The invention relates to a hydraulic actuator for the control of valves such as the kind found in ships. The actuator has a piston which is actuated in a valve opening direction with a hydraulic pressure medium and may be actuated in the return direction by a gas-compression type spring. Certain emergency situations require an immediate closing of a valve or group of valves controlled by the piston acting through a spindle. Emergency closing apparatus includes an abutment on the piston which forms an annular chamber when the piston abuts the end wall of the piston cylinder. The housing has an emergency passage means in fluid communication with the annular chamber when the piston abuts the end wall to effect an emergency moving of the piston in a valve closing direction when a pressure medium is admitted into the emergency passage.
    Type: Grant
    Filed: September 12, 1984
    Date of Patent: January 14, 1986
    Assignee: Danfoss A/S
    Inventor: Joergen Soendergaard
  • Valve apparatus for evacuating and/or filling a refrigeration system
    Patent number: 4561264
    Abstract: The invention relates to a valve apparatus for evacuating and/or filling a refrigeration system having a hermatically closeable connecting tube. The apparatus includes a piston and cylinder unit which has a central passage for receiving such a connecting tube and is pressure operable to squeeze a sealing ring into sealing engagement with the tube to facilitate the subsequent filling or evacuating of the system through the tube via valving located in a valve block connected to the piston.
    Type: Grant
    Filed: October 17, 1984
    Date of Patent: December 31, 1985
    Assignee: Danfoss A/S
    Inventor: Gustav A. Johansson
  • Pneumatic setting device
    Patent number: 4561345
    Abstract: The invention relates to a pneumatic setting device having oppositely operable magnetic valves for alternately pressurizing and exhausting expansible chambers formed by one or more diaphragms to which a reciprocatable setting element is attached. In this construction a return spring may be omitted.
    Type: Grant
    Filed: October 25, 1984
    Date of Patent: December 31, 1985
    Assignee: Danfoss A/S
    Inventors: Knud Blohm, Hans P. B. Petersen
  • Hydrostatic steering device steering wheel travel limits
    Patent number: 4558759
    Abstract: The invention relates to a hydrostatic steering device having a servomotor connectable to wheels to be steered. The travel limits of the servomotor are sensed with position sensors which function to operate a locking apparatus which mechanically prevents further turning of the steering wheel upon a travel limit being reached in either direction.
    Type: Grant
    Filed: December 1, 1983
    Date of Patent: December 17, 1985
    Assignee: Danfoss A/S
    Inventors: Johannes V. Baatrup, Harry E. Pedersen
  • Tool, particularly a boring tool
    Patent number: 4557338
    Abstract: This invention relates to a fluid pressure operated tool of the type having an axially reciprocatable and rotatable shaft to which a work piece such as a rock drill is attachable. The tool is driven by a planetary piston type of motor with a rotary externally toothed gear member having rotational and orbital movement relative to a surrounding internally toothed gear member. The externally toothed gear member is connected to a rotatable valve member and reciprocatable and rotatable output shaft by a cardan type shaft. The output shaft has a piston part which is subject to being alternately pressurized in opposite directions to produce the reciprocating motion.
    Type: Grant
    Filed: November 25, 1983
    Date of Patent: December 10, 1985
    Assignee: Danfoss A/S
    Inventor: Johannes V. Baatrup
  • Hydrostatic control device, particularly steering device
    Patent number: 4557676
    Abstract: The invention relates to a hydrostatic steering control device of the type having two motor ports connectable to a servomotor and a metering unit for metering the flow of fluid to or from the servomotor in accordance with the rotational movement of a steering wheel for operating the control device. The invention is directed to a way of balancing the distributing valve of the control device by subjecting opposite sides thereof to high and intermediate pressure zones and providing a throttle gap between the high and intermediate pressure zones an a second oppositely acting throttle gap between the intermediate pressure zone and a third zone of lower pressure.
    Type: Grant
    Filed: November 10, 1983
    Date of Patent: December 10, 1985
    Assignee: Danfoss A/S
    Inventors: Hans C. Petersen, Erik Kyster, Svend E. Thomsen
  • Apparatus for conveying liquids
    Patent number: 4554791
    Abstract: The invention relates to an apparatus for conveying liquids of which the vapor pressure is above atmospheric at ambient temperatures from a storage container to a delivery point, particularly for dispensing refrigerant.
    Type: Grant
    Filed: December 30, 1983
    Date of Patent: November 26, 1985
    Assignee: Danfoss A/S
    Inventor: Gustav A. Johansson
  • Hydraulic slide valve
    Patent number: 4548239
    Abstract: The invention relates to a hydraulic control valve assembly for controlling a consumer unit such as a servomotor of a vehicle steering system. The valve assembly has a conventional port arrangement which includes two selectively pressurizeable and drainable motor ports connectable to a servomotor and supply and exhaust ports connectable respectively to a pump and a drain tank. A slide valve has a central wall section between two motor ports which completely block a central supply port when the slide valve is in a neutral position. Two metering control load sensing ports are on opposite sides of the supply port and when the slide valve is in a neutral position the load sensing ports are in throttling relation to the slide valve motor ports.
    Type: Grant
    Filed: January 16, 1984
    Date of Patent: October 22, 1985
    Assignee: Danfoss A/S
    Inventor: Christian Eskildsen
  • Hydraulic control apparatus for a servomotor
    Patent number: 4548035
    Abstract: The invention relates to a steering control unit for a bidirectional servomotor which is connectable to steerable wheels. A steering wheel controlled quantity setting unit of a known type has ports connectable to a pump and a return tank and two control ports through which metered quantities of fluid flow to opposite sides of the servomotor and to other parts of the apparatus for actuating the servomotor. A directional control valve for selectivity directing pressurized fluid from a power circuit to opposite sides of the servomotor is controlled by a control circuit containing the setting unit. A utility valve having pressure regulating and control and power valve capabilities is provided. In cases wherein the quantity setting apparatus is remotely located from the regulating valve the length of the signal channels add to the reaction time.
    Type: Grant
    Filed: November 12, 1982
    Date of Patent: October 22, 1985
    Assignee: Danfoss A/S
    Inventors: Svend E. Thomsen, Thorkild Christensen
  • Casing for electrical equipment
    Patent number: D281315
    Type: Grant
    Filed: October 7, 1983
    Date of Patent: November 12, 1985
    Assignee: Danfoss A/S
    Inventor: Lehmann Kjeld
  • Casing for electrical apparatus or the like
    Patent number: D281969
    Type: Grant
    Filed: February 4, 1983
    Date of Patent: December 31, 1985
    Assignee: Danfoss A/S
    Inventor: Jorgen J. Moeller