Patents Assigned to Gebr. Hofmann KG
  • Patent number: 4104919
    Abstract: A circuit and process for eliminating unbalances on a rotor which permits equalization of unbalance only in constructionally predetermined equalization planes and component angles in which conventionally produced balance signals indicating the amounts and angles of unbalance are rectified and applied to an arithmetic circuit which produces output signals indicating the amounts of unbalance in equalization planes and, where balance in a given equalization plane is not possible, the amount of unbalance in a substitute plane. To permit balancing of different type workpieces having different dimensions, potentiometers are connected to the arithmetic circuit and to a longitudinal positioning circuit for applying signals indicating locations of the planes.
    Type: Grant
    Filed: July 16, 1976
    Date of Patent: August 8, 1978
    Assignee: Gebr. Hofmann KG, Maschinenfabrik
    Inventor: Hermann Brunnengraber
  • Patent number: 4102435
    Abstract: A safety unit for latching against upward movement a spindle driven lift of the type having a lifting nut on which a lifting carriage guided in a column is supported and a safety nut mounted for movement on the spindle for guiding the column in the event of lifting nut failure with a pawl rotatably mounted adjacent the tooth spindle for rotating, urged by a spring, to a locking position preventing rotation of the spindle in one direction when a guide bolt extending through one of a pair of contiguous bores in the pawl having different diameters is shifted axially in response to lifting nut failure, the bolt having different diameter portions along its axis so that the shifting permits rotation of the pawl into its locking position.
    Type: Grant
    Filed: July 30, 1976
    Date of Patent: July 25, 1978
    Assignee: Gebr. Hofmann KG
    Inventor: Dionys Hofmann
  • Patent number: 4063462
    Abstract: An apparatus for determining static imbalance of a test body with a receiving plate mounted gimbal-fashion in antifriction bearings with data receivers connected to the receiving plate whereby the receiving plate is supported radially, i.e., in a direction perpendicular to the plane of the gimbal axes, by antifriction bearings and axially, i.e., in the plane, by axially rigid torsion rods.
    Type: Grant
    Filed: May 7, 1976
    Date of Patent: December 20, 1977
    Assignee: Gebr. Hofmann KG
    Inventor: Gunther Himmler
  • Patent number: 4055081
    Abstract: A method and appartus for measuring forces of reaction of a wheel rim and tire so as to minimize smooth road vibrations whereby the wheel and rim are rotated together in a first measuring run, the wheel and rim are rotated with respect to each other by a predetermined angle, and the wheel and rim are rotated together in a second run. The offset angle which minimizes vibrations can then be determined from the reaction forces of the two runs and the wheel and rim rotated with respect to each other to that offset angle.
    Type: Grant
    Filed: February 24, 1977
    Date of Patent: October 25, 1977
    Assignee: Gebr. Hofmann KG, Maschinenfabrik
    Inventor: Herwig Honlinger
  • Patent number: 4050195
    Abstract: An apparatus for mounting a grinding wheel of the type having a spindle which is rotated by a motor or the like and on which is mounted a grinding wheel and a machine housing between the wheel end drive. A balancing structure includes a first annular housing mounted on the spindle adjacent the wheel and means mounted on the machine housing for injecting a balancing fluid into the annular housing and a second housing mounted on the spindle adjacent the spindle drive.
    Type: Grant
    Filed: August 6, 1976
    Date of Patent: September 27, 1977
    Assignee: Gebr. Hofmann KG, Maschinenfabrik
    Inventor: Dionys Hofmann
  • Patent number: 4031760
    Abstract: An apparatus for clamping and centering bodies during rotation for balancing with a body receiving plate which is mounted on a spindle and which has a pair of concentric flexible rings or gaskets mounted on the upper surface thereof to define, when the body rests on the rings, a vacuum chamber from which air is removed to lock the body in place by channels which extend through the plate and communicate with the vacuum chamber. A housing extends about and is connected to the spindle by bearings with the space between the housing and spindle communicating with the vacuum chamber and with a connection extending through the housing for removing air from the vacuum chamber. Extensions of the spindle and vent holes between the housing space and the bearing prevent a vacuum from being developed in the area of the bearings.
    Type: Grant
    Filed: April 14, 1976
    Date of Patent: June 28, 1977
    Assignee: Gebr. Hofmann KG
    Inventor: Richard Muller
  • Patent number: 4019136
    Abstract: An electrical circuit for digitally displaying an input electrical signal to minimize fluctuations in the output and maximize the speed of response to changes in the input signal whereby the input signal is applied to a first low pass filter and a second low pass filter having both a lower threshold frequency and a slower response time to changes in the input signal than the first filter. The outputs of the two filters are applied to a differential amplifier to produce a differential signal which is applied via a pair of serially and oppositely connected Zener diodes to the output of the second filter, which is also connected to the digital display, to cause rapid response to signal changes. The frequency of a unijunction oscillator is also controlled by the differential signal to increase the measuring rate of the digital display whenever the input signal charges by more than a predetermined value.
    Type: Grant
    Filed: December 29, 1975
    Date of Patent: April 19, 1977
    Assignee: Gebr. Hofmann KG
    Inventor: Friedrich Wenz
  • Patent number: 4018087
    Abstract: A method and apparatus for testing the uniformity of a rotary body whereby an electrical analysis signal is produced by travel measuring or force measuring transducers having an amplitude which varies as a function of the non-uniformities, multiplied by a direct current signal which varies as a function of the speed of rotation of the body to produce a further signal which is then integrated to provide the Fourier coefficients of the Fourier development series of the analysis signal.
    Type: Grant
    Filed: August 2, 1976
    Date of Patent: April 19, 1977
    Assignee: Gebr. Hofmann KG
    Inventor: Friedrich Wenz
  • Patent number: 4004464
    Abstract: A method and apparatus for selectively measuring oscillation components and vectors in a spectrum, particularly produced by detecting unbalance of a rotary body, with a transducer which includes a pair of coils which move in an alternating magnetic field having an adjustable frequency and an integrating circuit connected to the transducer output so that the desired components are selected in the transducer and integrating circuit.
    Type: Grant
    Filed: August 12, 1975
    Date of Patent: January 25, 1977
    Assignee: Gebr. Hofmann KG Maschinenfabrik
    Inventor: Gunther Himmler
  • Patent number: 4002076
    Abstract: A method and circuit for use in determining unbalance of a rotary body having structurally predetermined compensation planes and restricted angular regions thereof in which the unbalance signals of the respective compensation planes are produced and applied to respective first and second inverting amplifiers if the compensation cannot be carried out in the compensation planes and a substitute plane is required. The outputs of the first and second amplifiers are added in a third amplifier whose output value varies as a function of the distance of the substitution plane from a compensation plane so that the output of the second amplifier, with the output of the first amplifier applied to its input, indicates the compensation in the substitution plane and the output of the third amplifier indicates the compensation in the other compensation plane.
    Type: Grant
    Filed: April 26, 1976
    Date of Patent: January 11, 1977
    Assignee: Gebr. Hofmann KG
    Inventor: Hermann Brunnengraber
  • Patent number: 3999275
    Abstract: A tool for driving balance weights of the type having the shape of a slotted bushing which is attached to a spoke nipple by a press fit, the tool having a handle at one end and a weight receiving opening at the other. A lateral slot communicates with the opening for receiving a spoke and a crowned anvil is provided between the ends for hammering the weight in place against the rim without deforming the weight.
    Type: Grant
    Filed: February 27, 1976
    Date of Patent: December 28, 1976
    Assignee: Gebr. Hofmann KG
    Inventor: Gunter Schmidt
  • Patent number: 3981174
    Abstract: A method and apparatus for testing shock absorbers installed on vehicles whereby one tire of the vehicle is placed on a supporting plate of a test stand which is oscillated. The velocity of the plate during oscillation and the dynamic tire pressure on the supporting plate are detected and corresponding signals produced. The signals are divided, one by the other, after being peak rectified to produce a quotient which represents tire quality signal. Resonance is detected by differentiation of the velocity signal and the tire quality signal transmitted to an indicator only during resonance.
    Type: Grant
    Filed: September 19, 1975
    Date of Patent: September 21, 1976
    Assignee: Gebr. Hofmann KG
    Inventor: Gunther Himmler
  • Patent number: 3969933
    Abstract: A joint for connecting a drive unit to a measuring arrangement connected to a wheel. The measuring arrangement comprising a wheel shaft rotatably supported by a measuring hub having deformable beams for measuring moments and forces acting on the wheel and the joint comprising a diaphragm flexible in the axial direction but rigid in the peripheral direction connected between the wheel shaft and one end of a cylindrical tube which is radially resilient and axially rigid, the other end of the tube being coupled to the drive unit.
    Type: Grant
    Filed: October 21, 1974
    Date of Patent: July 20, 1976
    Assignee: Gebr. Hofmann KG
    Inventor: Gunther Himmler
  • Patent number: 3967701
    Abstract: A lifting apparatus of the type having a number of columns supporting a load platform each column driven by an electrical, polyphase current motor whereby sensors on each column, for example potentiometers, produce a signal indicating the height of that column. The signals are applied to a comparator which in turn provides an output to one or more electronic switches, such as a triac or thyristor having a diode connected in parallel with it for conducting current in an opposite direction, each such switch connected to a winding of a motor to control the current applied so as to reduce any difference in height among the columns.
    Type: Grant
    Filed: October 9, 1974
    Date of Patent: July 6, 1976
    Assignee: Gebr. Hofmann KG
    Inventor: Horst Hegenbart
  • Patent number: 3967416
    Abstract: A balancing apparatus, particularly for a grinding wheel, whereby the wheel has four individual chambers disposed around its axis of rotation with each chamber connected to one face of the ring shaped container by a slot formed in a circular recess at a different radius so that the wheel can be balancing by injecting cooling fluid or the like into the slots to temporarily add fluid to selected chambers, and each chamber is separated from adjoining chambers by dividing walls which extend from inner to outer ring. The inner ring is tapered toward a central opening to ensure complete emptying after balancing.
    Type: Grant
    Filed: August 12, 1975
    Date of Patent: July 6, 1976
    Assignee: Gebr. Hofmann KG
    Inventors: Dieter Birkenstock, Otto Jager
  • Patent number: 3961525
    Abstract: A method and apparatus for testing the fatigue strength of a stationary rotor whereby the rotor is clamped to an exciter rod and opposite transverse forces applied to the rod at different distances from the point of clamping by rotating weight to produce substantially no net radial forces.
    Type: Grant
    Filed: September 13, 1974
    Date of Patent: June 8, 1976
    Assignee: Gebr. Hofmann KG
    Inventor: Gunther Himmler
  • Patent number: 3950897
    Abstract: A balancing apparatus, particularly for a grinding wheel, whereby the wheel has four chambers disposed around its axis of rotation with each chamber connected to one face of the ring shaped container by a slot formed in a circular recess at a different radius so that the wheel can be balancing by injecting cooling fluid or the like into the slots to temporarily add fluid to selected chambers.
    Type: Grant
    Filed: November 12, 1974
    Date of Patent: April 20, 1976
    Assignee: Gebr. Hofmann KG
    Inventors: Dieter Birkenstack, Otto Jager
  • Patent number: 3948004
    Abstract: An apparatus whereby the lateral and radial forces arising in a loaded tire -- either standing or rolling -- are detected and signals produced to control grinding units as a function of both forces to remove material and reduce or eliminate non-uniformities.
    Type: Grant
    Filed: August 28, 1974
    Date of Patent: April 6, 1976
    Assignee: Gebr. Hofmann KG
    Inventor: Peter Max Gruber