Gebr.hofmann Gmbh & Co Kg Maschinenfabrik

Hofmann Maschinenbau Gmbh

Gebr. Hofmann Kg

Hofmann Werkstatt-technik Gmbh

Gebr. Hofmann Gmbh & Co. Kg

Gebr. Hofmann G.m.b.h. Kg, Maschinenfabrik

Gebr. Hofmann, G.m.b.h. & Co., Maschinenfabrik

Gerb. Hofmann Gmbh & Co. Kg

Dr.-ing.wolfgang Schulz Messtechnik

Gunther Himmler

Gunter Knoll

Friedrich Wenz

Herwig Honlinger

Werner Lehr

Uwe Moench

Horst Kogler

Werner Bickelhaupt

Wolfgang Schulz

A method and apparatus for dynamically balancing a rotary member by mass compensation in first and second correction planes on the rotary member, wherein in dependence on the rotary member mass, its mass moment of inertia, the measuring speed of rotation and the spacing of the correction planes from the measuring planes, measurement value vectors which are supplied by measuring sensors in the measuring planes are turned through angles which are obtained from a respective stored family of curves produced by means of test runs. Each family of curves represents phase shifts of the measurement vectors relative to the correction vectors in the correction planes in dependence on the rotary member mass, the mass moment of inertia, the speed of measuring rotation and the spacing of the rotary member or the correction plane from the measuring plane.

Method and apparatus for dynamically balancing a rotary member

A measuring apparatus for measuring forces which occur when a rotary body is clamped on a testing machine drive shaft include a face clamping force measuring means for measuring face clamping forces acting between said rotary body and a clamping element contact face which is disposed perpendicularly to the axis of the rotary body, and/or a radial clamping force measuring means for measuring a radial clamping force acting between said rotary body and a radially outwardly acting clamping means.

Measuring apparatus for measuring forces which occur when a rotary body

A method of unbalance measurement of a rotary member for balancing thereof in first and second compensating planes includes the steps of: performing test runs wherein the rotary member is rotated about is axis with test weights on the rotary member rotating in different planes thereof, the planes being perpendicular to the axis of rotation of the rotary member, and in each test run the effects of centrifugal forces produced by the test weights are measured simultaneously in more than two measuring planes which differ from the planes in which the test weights rotate so as to provide correlation coefficient matrices in the respective measuring planes; evaluating all of the determinants associated with a given type of rotary member; and ascertaining unbalance vectors of a rotary member of a given type in the respective measuring planes by use of the measuring planes which are determined by the correlation coefficient matrix whose determinant is greatest for that type of rotary member.

Method and apparatus for unbalance measurement for unbalance

In a method and apparatus for improving the fit of a pneumatic tire on a motor vehicle wheel rim, before a wheel balancing operation is carried out the wheel is accelerated to a maximum permissible peripheral speed and centrifugal force acting at the wheel is measured at that speed. The drive for the wheel with tire thereon is stopped when the measured variation in centrifugal force reaches or falls below a predetermined limit value.

Method and apparatus for improving the fit of a pneumatic tire on a

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.

Rotary member measuring apparatus with improved support bed

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.

Process and apparatus for testing the uniformity of pneumatic tires

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.

Apparatus for testing motor vehicle tires

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.

Method and apparatus for determining the uniformity of pneumatic tires

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.

Apparatus for checking motor vehicle tires

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.

Apparatus for monitoring and controlling the tire inflation pressure in

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.

Bar spring support for a rotor shaft housing in an oscillation measuring

A method and device for the balancing of a rotor in two planes. A static imbalance is formed from the result of imbalance vectors measured in the planes. Balance weights are fixed on the rotor in those angle positions so that a minimized static imbalance is provided.

Method for balancing a rotor, in particular a motor vehicle wheel, in

In order to improve running characteristics of an automobile wheel comprised of rim and respective tire fitted thereon and presenting spring qualities, a matching procedure is used to readjust the tire and rim in clearly defined positions relative to each other. Radial run-out effects both of rim and tire are so arranged in opposite directions as to reduce the resulting radial run-out of the wheel. The matching consists in detail of opposing resultant tire radial force variations mathematically calculated on the basis of non-uniform mass distribution in the contact area of the tire under load with differences in tire spring rate on the one hand and radial run-out of the rim on the other hand.

Method and apparatus for improvement of wheel running conditions

A unitary adaptor plate for determining static unbalance in a body. The plate includes an outer body, a middle body, and an inner body, and each of the inner and outer bodies is connected to the middle body by means of opposed torsion elements to provide a structure that defines a gimbal system capable of rotation about two mutually perpendicular axes of rotation defining two degrees of freedom of the adaptor plate. Deflection sensors sense the inclination of the adaptor plate caused by unbalance in a body placed on the adaptor plate, and force transducers operate to restore the plate to a horizontal position and provide an output indicative of the unbalance of the body.

Apparatus for determination of the static unbalance in a body

A method and an apparatus for determination of run-out of a rotating body, especially an automobile tire, without the need for mechanically contacting the rotating body. The apparatus includes a device for rotating the body, a scanning system with a transmitter for transmitting parallel rays directed toward the rotating body, a receiver to receive the residual rays not blocked by the rotating body, and an analyzer circuit for determination of variations in blockage on the basis of which run-out of the rotating body is determined.

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Darmstadt, Germany

Gunther Himmler