Patents Assigned to Gebr. Hofmann GmbH
  • Patent number: 5676025
    Abstract: An apparatus for balancing a rotary member such as a grinding wheel has at least one balancing weight which is guided movably for varying its position with respect to the axis of rotation of the rotary member. The balancing position of the balancing weight is adjusted by means of at least one displacement device including an electric motor. The motor is arranged with its axis of rotary oriented radially with respect to the axis of rotation of the rotary member. The rotor of the motor can be supported by way of a thrust bearing against a main body portion.
    Type: Grant
    Filed: December 15, 1995
    Date of Patent: October 14, 1997
    Assignee: Gebr. Hofmann GmbH & Co. KG Maschinenfabrik
    Inventor: Eugen Lulay
  • Patent number: 5243788
    Abstract: In a method and an apparatus for balancing a grinding wheel, balancing weights on the grinding wheel remain secured to the grinding wheel in an unbalance measuring operation, and the positions at which the balancing weights are secured to the grinding wheel are stored. In a repositioning operation for compensating for measured unbalance of the grinding wheel, the influences of the forces of the balancing weights during the unbalance measuring operation are derived from the stored positions of the weights and compensated for so as to balance the ginding wheel.
    Type: Grant
    Filed: August 15, 1990
    Date of Patent: September 14, 1993
    Assignee: Gebr. Hofmann GmbH & Co., KG Maschinenfabrik
    Inventors: Gunther Rossmann, Jesus Varona, Andreas Hofmann
  • Patent number: 5178011
    Abstract: In a method and an apparatus for balancing successive rotary members, an unbalance measuring operation is carried out in one or more planes on each rotary member which is rotated at a measuring speed in a measuring run within an overall unbalance measuring time for ascertaining the required number of items of measuring information in a plurality of repetitive measuring cycles. After the elapse of a fraction of the overall unbalance measuring time the unbalance measuring operation is interrupted for an interruption time for the purposes of permitting the performance of working operations which due to vibration caused thereby could result in falsification of the unbalance measurement results, then unbalance measurement is resumed, and further interrupted, and so on in a repetitive procedure to make up the overall measurement time.
    Type: Grant
    Filed: August 15, 1990
    Date of Patent: January 12, 1993
    Assignee: Gebr. Hofmann GmbH & Co. KG Maschinenfabrik
    Inventors: Klaus-Peter Ohms, Jesus Varona
  • Patent number: 5138882
    Abstract: In a method and apparatus for measuring static unbalance of a rotary member, involving determining the axial moment of inertia of the rotary member which is mounted pivotably in a horizontal position in a balancing system, about an axis of the balancing system, a deviation of the rotary member from its horizontal position is detected and a return force for returning the rotary member to the horizontal position is produced in response to a control parameter from a regulating circuit in dependence on the detected deviation, with regulation of the return force also being effected in dependence on the weight of the rotary member. The value of the static unbalance of the rotary member is formed from the measured return force.
    Type: Grant
    Filed: May 15, 1990
    Date of Patent: August 18, 1992
    Assignee: Gebr. Hofmann GmbH & Co. KG Maschinenfabrik
    Inventors: Kurt Humber, Gunther Rossmann
  • Patent number: 5125271
    Abstract: A method and an apparatus for balancing a rotor, in which compensation points are distributed symmetrically on the rotor's circumference about the axis of the rotation, which compensation points are suitable for an imbalance compensation by means of a component revolving with the rotor and on its circumference having scannable structural elements, pulses are generated that provide information for the respective rotational angle position of the rotor for determining the imbalance angular position and for indexing the rotor after the imbalance measuring run into the compensation angle position, and this component may be embodied as a gear wheel or fan wheel.
    Type: Grant
    Filed: April 15, 1991
    Date of Patent: June 30, 1992
    Assignee: Gebr. Hofmann GmbH & Co., KG
    Inventor: David R. Hallberg
  • Patent number: 5067348
    Abstract: A measuring apparatus in which a rotary member is mounted and rotated for measurement or testing thereof, with measuring devices including measurement value pick-up structures for periodically detecting varying forces and/or moments caused by the rotating rotary member. The measuring apparatus includes a machine bed which serves as a component for carrying the measuring devices and for mounting the rotary member. The machine bed is in the form of a casting comprising polymer concrete.
    Type: Grant
    Filed: April 19, 1990
    Date of Patent: November 26, 1991
    Assignee: Gebr. Hofmann GmbH & Co. KG Maschinenfabrik
    Inventors: Gunther Himmler, Uwe Moench
  • Patent number: 5067347
    Abstract: In a method and an apparatus for testing a pneumatic tire such as for testing the uniformity thereof, a tire to be tested is inflated to a given pressure and rolled against a test surface at a tire contact patch, and forces and/or moments acting at the contact patch are measured. To at least reduce the period of time required for the tire to warm up for a testing operation, the compressed air used to inflate the tire is heated to a given temperature before being passed into the interior of the tire. The compressed air may be heated as it flows through a supply conduit, under the control of a sensor for sensing the temperature in the tire.
    Type: Grant
    Filed: July 19, 1990
    Date of Patent: November 26, 1991
    Assignee: Gebr. Hofmann GmbH & Co. KG Maschinenfabrik
    Inventor: Uwe Monch
  • Patent number: 5040413
    Abstract: A process and an apparatus for testing the uniformity of a pneumatic tire such as a vehicle tire provide that fluctuations in tire inflation pressure are measured during a uniformity-testing measuring run in which the tire to be tested is rolled against a test surface under a given loading, with force fluctuations occurring at the contact surface therebetween, and in which a compensation value is formed from the measured fluctuations. The compensation value is combined with the measured force fluctuations thereby to eliminate force fluctuation components attributable to fluctuations in the tire inflation pressure.
    Type: Grant
    Filed: May 10, 1990
    Date of Patent: August 20, 1991
    Assignees: Gebr. Hofmann GmbH, Co. KG Maschinenfabrik
    Inventor: Klaus-Peter Ohms
  • Patent number: 5033302
    Abstract: A mounting stand in a balancing machine mounting assembly includes a stationary mounting block and a mount for a rotary member to be balanced. The mount is supported on the mounting block by two parallel springs capable of oscillating movement in a mounting plane in the measurement direction. The mounting stand further has at least one measurement value pick-up sensor operatively disposed between the mounting block and the oscillatable mount for detecting oscillation of the mount produced by an out-of-balance rotary member and to supply corresponding measurement signals. A rotatable adjusting unbalance weight of a known magnitude is mounted to the oscillatable mount and can be selectively brought into operation to cause oscillatory movement of the oscillatable system, to perform a calibration.
    Type: Grant
    Filed: January 3, 1990
    Date of Patent: July 23, 1991
    Assignee: Gebr. Hofmann GmbH & Co. KG Maschinenfabrik
    Inventor: Uwe Monch
  • Patent number: 5027649
    Abstract: In a process and an apparatus for testing the uniformity of pneumatic tires, a fluctuation in radial force is measured and subtracted therefrom is a correction value derived from individual rotational truth profiles in respect of the testing drum, in radial planes which are normal to the axis of the drum.
    Type: Grant
    Filed: May 10, 1990
    Date of Patent: July 2, 1991
    Assignee: Gebr. Hofmann GmbH & Co. KG
    Inventor: Gunther Himmler
  • Patent number: 5019017
    Abstract: In a monitoring arrangement for a belt drive in which a torque produced by a drive motor is transmitted by way of an endless drive belt to a rotary member to be rotated, the drive belt is provided in its longitudinal direction with markings which are adapted to be sensed and which are disposed at equal spacings from each other. First and second sensing members are arranged at a given spacing from each other in succession in the direction of travel of the belt and are operable to sense the markings on the drive belt as they move past the sensing members. The sensing members output corresponding sensing signals in response to the markings. A signal evaluation member is connected to the first and second sensing members, for interrelating the sensing signals in respect of time in dependence on the spacing between the first and second sensing members and the speed of movement of the drive belt.
    Type: Grant
    Filed: February 5, 1990
    Date of Patent: May 28, 1991
    Assignee: Gebr. Hofmann GmbH & Co. KG Maschinenfabrik
    Inventor: Uwe Monch
  • Patent number: 5016470
    Abstract: In an apparatus for testing a motor vehicle tire and in particular for ascertaining characteristic parameters of a bead thereof, the bead of the tire is subjected to stretching by radially outwardly displaceable clamping jaws and the compression force applied to the tire by the respective clamping jaws are measured by force measuring means. Each of the force measuring means includes a respective measuring body in which a force transmission portion carries the actuating force applied to the respective clamping jaw and experiences deformation in consequence of the force. The force transmission portion bears strain gauges to measure the force, and it is supported by resiliently bendable support portions in such as way that the measuring body is substantially insensitive to moments and transverse forces which could result from radial guidance for the clamping jaws.
    Type: Grant
    Filed: July 27, 1990
    Date of Patent: May 21, 1991
    Assignee: Gebr. Hofmann GmbH & Co. KG Maschinenfabrik
    Inventor: Gunther Himmler
  • Patent number: 4989449
    Abstract: In a method and an apparatus for determining the restoring moment produced by tangential forces in a tire testing operation, a tire to be tested is rolled against a test surface under identical rolling conditions in first and second measuring runs, the second of which is performed with the tire being turned round through 180.degree. from its position in the first measuring run. The restoring moment which is related to the center of the contact surface at which the tire is in contact with the test surface is formed from the restoring moment values which are obtained in the first and second measuring runs.
    Type: Grant
    Filed: January 18, 1990
    Date of Patent: February 5, 1991
    Assignee: Gebr. Hofmann GmbH & Co. KG Maschinenfabrik
    Inventor: Uwe Monch
  • Patent number: 4964299
    Abstract: An arrangement for measuring, in a tire testing machine, radial and axial forces at a wheel consisting of a pneumatic tire and a rim. The measuring axle, on which the wheel is rotatably disposed during the measuring run, has two cylindrical axle parts, of which the first, interior axle part is mounted so that it can be moved radially and frictionlessly in a straight line, and the second, exterior axle part, in axial direction, is frictionlessly located on the first axle part. For introduction of the axial forces, a first force measuring device is provided that is connected with a tension-compression rod that is rigidly connected with the second axle part, and for measuring the radial forces, a second force measuring device is connected between the base plate and the first axle part.
    Type: Grant
    Filed: July 15, 1988
    Date of Patent: October 23, 1990
    Assignee: Gebr. Hofmann GmbH & Co. KG
    Inventors: Manfred Maier, Franz Ruppert, Joachim Schwab
  • Patent number: 4955229
    Abstract: A method and apparatus is proposed for determining the uniformity of pneumatic tires. The apparatus has two measuring rim halves between which a tire to be tested can be mounted and rolled along a test drum. The apparatus has a measuring system for measuring force fluctuations resulting from nonuniformities of the tire and for emitting a corresponding signal, and an evaluation system which evaluates tire uniformity by subtracting a correction signal obtained from eccentricities of the measuring rim halves from a measurement signal. In this way, a compensation of the error component in the measurement signal resulting from eccentricity of the rim halves is obtained.
    Type: Grant
    Filed: October 20, 1989
    Date of Patent: September 11, 1990
    Assignee: Gebr. Hofmann GmbH & Co. KG Maschinenfabrik
    Inventor: Gunther Himmler
  • Patent number: 4941352
    Abstract: In a method and apparatus for mass centering of a rotor, the unbalance of the rotor is measured and the result of the unbalance measuring operation and the weight of the rotor are used to determine the position of the axis of inertia which extends through the center of mass of the rotor, with respect to the axis of rotation thereof. The position of the axis of inertia is marked on an end face of the rotor by a marking tool. For that purpose, to bring the position of the axis of inertia and the marking tool into the appropriate relationship, relative displacement is produced by an actuating means as between the rotor and the marking tool in the radial direction with respect to the axis of rotation of the rotor, with the rotor or the marking tool being guided in the direction of displacement by a guide means disposed at an angle with respect to the axis of rotation of the rotor.
    Type: Grant
    Filed: May 5, 1989
    Date of Patent: July 17, 1990
    Assignee: Gebr. Hofmann GmbH & Co. KG Maschinenfabrik
    Inventor: Gunter Fietzke
  • Patent number: 4923326
    Abstract: A clamping ring for clamping a member such as a rotor on a shaft comprises a ring member formed by a plurality of ring segment portions which are displaceable relative to each other in the peripheral direction of the ring member, and spring elements disposed in the respective gaps between adjacent ring segment portions, thereby connecting the ring segment portions together. The clamping ring is fitted into an opening in the member such as a rotor, and the clamping action is produced by a variation in the inside and/or outside diameter of the ring member, by virtue of the ring segment portions being displaced relative to each other in the peripheral direction only in the plane of the ring member.
    Type: Grant
    Filed: February 10, 1989
    Date of Patent: May 8, 1990
    Assignee: Gebr. Hofmann GmbH & Co.
    Inventor: Gunter Fietzke
  • Patent number: 4918983
    Abstract: In an apparatus for checking a motor vehicle tire the bead of a tire is subjected to a stretching effect by radially outwardly displaceable clamping jaws, and the compression force applied to the bead by the respective clamping jaws is measured by force measuring means. Each force measuring means comprises a radially movable frame structure in which a central force transmitting portion connected to the respective clamping jaw is supported movably in relation to outer portions of the frame structure by resiliently bendable support portions bearing strain gauges, in such a way that when a tire is clamped by the clamping jaws, the force transmitting portion is displaced, causing deformation of the support portions, such deformation being measured by means of the strain gauges. The force transmtting portion is supported in the frame structure in such a way that it is substantially insensitive to movements and transverse forces which can result from radial guidance for the clamping jaws.
    Type: Grant
    Filed: April 28, 1989
    Date of Patent: April 24, 1990
    Assignee: Gebr. Hofmann GmbH & Co. KG Maschinenfabrik
    Inventor: Gunther Himmler
  • Patent number: 4916943
    Abstract: An apparatus for monitoring and controlling the tire inflation pressure in a tire testing machine comprises first and second measuring rim portions for mounting a tire therebetween, and a pressure sensor operable to detect the inflation pressure of the tire. The pressure sensor has a pressure-receiving surface which is arranged to directly detect the pressure in the interior of the tire. The pressure sensor rotates with the tire in a tire testing run. A spindle connected to the measuring rim portions and rotatable therewith has conduit means for supplying compressed air to inflate the tire. A control means is operable to close off the conduit means, thereby constituting a closed volume of air defined by the space within the tire, the space between the measuring rim portions holding the tire, and the conduit means in the spindle, that volume of air rotating as a unit with the components defining same, during a tire testing operation.
    Type: Grant
    Filed: July 13, 1989
    Date of Patent: April 17, 1990
    Assignee: Gebr. Hofmann GmbH & Co. KG Maschinenfabrik
    Inventors: Gunther Himmler, Werner Lehr
  • Patent number: 4905515
    Abstract: A device for measuring rotor imbalance of a rotor is disclosed. The rotor shaft housing support for the shaft for a rotor to be balanced in a machine includes two pairs of springs disposed in two parallel planes. Each pair of springs consists of two parallel bar or rod springs that support the rotor shaft housing support in a plane of oscillation coincident with the shaft of the rotor on the machine stand in such a way that it oscillates. Each of the two bar or rod springs of each pair of springs forms part of a single-piece frame. Mounting strips are attached to the machine stand and to the rotor shaft housing.
    Type: Grant
    Filed: May 13, 1988
    Date of Patent: March 6, 1990
    Assignee: Gebr. Hofmann GmbH & Co. KG Maschinenfabrik
    Inventor: Gunther Himmler