Gse, Inc.

Other

Rs Technologies Inc.

Ralph S Shoberg

Gary L Barrett

Thomas A Ulicny

Hossein Firouzegan

Hugh Fader

Kenneth R Kozlowski

The present invention is directed towards a method and an apparatus for accurately estimating the tension or clamp force in a bolted joint. An installed fastener is rotated and the torque necessary to rotate the fastener and the angle through which the fastener is rotated are measured. The angle and torque values are plotted against one another such that the angle values are plotted on an angle axis and the torque values are plotted on a torque axis. A tangent is extended from the plot towards the angle axis. The point at which the tangent crosses the angle axis is defined as zero degrees and is called the &ldquo;elastic origin&rdquo;. The known angle through which the fastener rotates is used to scale the angle axis. The angle from the elastic origin to the point at which the tangent was drawn is defined as the M-alpha angle and is directly proportional to the clamp force created by the bolted joint or tension in the fastener.

Method and apparatus for auditing a tension load in the threaded fastener

A transducer body having a traditional single-axis envelope capable of multi-axis measurements. The transducer body includes coaxial base ends with an intermediate flexure element in the form of a ring having an internally centered stiffening web which reduces deflection and localizes strain for accurate high-capacity single-axis load measurements, as well as for bending and shear. The invention further includes a novel arrangement of strain gages on the transducer body, preferably including three sets: strain gages on the stiffening web to measure single-axis loading along the longitudinal axis of the transducer body; bending measurement strain gages spaced at 45&deg; around the periphery of the ring element; and shear measurement strain gages located at 90&deg; locations on the periphery of the ring.

Three-axis transducer body and strain gage arrangement therefor

An improved tensiometer for measuring the amount of tension in a wire or cable comprises a hand-held sensor unit having a handle, two spaced support arms supporting cable-engaging support nibs, an extensible sensor nib protruding from the handle, and a trigger grip operable to extend the sensor nib upwardly between the support nibs to deflect a portion of cable clamped therebetween. The support nibs are eccentric and rotatably adjustable between a plurality of settings to permit the sensor unit to accommodate a number of different cable diameters, and the throw ratios of the nibs are arranged to minimize their eccentricity and the resulting variation in length of the deflected portion of cable at different settings. The sensor unit measures the force required to deflect the cable with a load cell, the output of which is converted into and displayed as a tension value by a microprocessor display meter connected to the sensor unit. The tensiometer is calibrated using a computerized linearization method to provide the microprocessor display meter with a linearization table for each diameter and type of cable to be tested.

Cable tensiometer

A method and apparatus for accurately determining the previously applied torque to a threaded fastener. Torque is increasingly applied to the fastener and measured periodically. The measurements are digitized and stored in a microprocessor. The torque previously applied is the torque that causes the fastener to breakaway or start to begin to turn. This breakaway point is the torque corresponding to a change in the slope of the applied torque-time relationship. The breakaway point is determined by determining the maximum different value between the measured torque and a mathematical line segment commencing from below the breakaway point and extending to the peak torque applied. The breakaway point (or applied torque) is the torque corresponding to the calculated maximum difference value.

Preexisting torque measuring device for threaded fasteners

A weigh scale apparatus in which forces caused by the applied load are transformed into moments of opposite sense and applied to opposite ends of a substantially rigid beam. Bending deflection of the beam is measured by centrally disposed strain gauge resistors to produce an electrical signal quantity proportional to the applied load. The conversion of applied load to moments of opposite sense is accomplished by a pair of spaced parallel pivot members which are suspended between the load receiving pan and the base such that the pivots tend to rotate in opposite directions. The beam is mechanically connected between the pivots such that it is subjected to the bending moment over substantially its entire length. A flexure hinge is provided adjacent each end of the beam to render the beam soft or compliant with respect to twisting forces imposed on the beam with the result that the twisting moment introduced into the beam in response to a given magnitude of twist is greatly reduced to a point where it generates no significant cross-talk in the beam such as would affect the accuracy of the bending stress being measured by the beam in response to the opposite rotation of the pivots.

Constant moment weigh scale with misalignment compensator

A weigh scale includes a flexure beam disposed between a platform and the base. Load transmitting devices operate to deflect the beam as a function of the load placed on the platform. Overload protection is provided for the beam to restrict the amount of beam deflection to maintain it within its elastic limits to thereby prevent yielding of the beam.

Overload protection for a weigh scale having a flexure beam

A load cell which may be embodied in an arch beam structure or a shear tension link and comprising a flexure area design which requires the machining of only five parallel holes. The five holes comprise a large central hole and four satellite holes to define two opposite load paths, each including two flexure areas which react to a load in opposite tension-compression sense. Strain gage resistors of the foil type are bonded onto the flexure areas and connected into a Wheatstone bridge circuit.

Load cell

A torque measuring apparatus having a head adapted to rotate about an axis of rotation and a lever arm extending from the head and perpendicular to the axis of rotation designed to react to normal forces applied at a distance from the head. On the lever arm are a plurality of strain transducers spaced apart a certain distance as determined in accordance with predetermined mechanical properties of the lever arm. The transducers are joined electrically to form a bridge circuit, the output of which is directly proportional to the torque on the workpiece. This output is then transmitted to a display for a visual presentation of the torque.

Torque measuring apparatus

A load cell of the shear-link type comprising a solid body of high modulus of elasticity material having a longitudinal axis of sensitivity and longitudinally spaced transverse slots entering the body from opposite directions to define the shear link. The body is bored out in the area of the shear link to create a stress concentration which is monitored using bonded-on strain gage resistors connected in a Wheatstone bridge circuit.

A load cell for measuring the torque and/or thrust forces in a driveline having a universal coupling joint, such as the drive shaft of an automobile. The load cell is designed to replace the standard cross element in the U-joint. Due to the operative association of the load cell with the driveline and the particular strain gage arrangement disclosed, the load cell is capable of accurately measuring the axial force and rotational torque transmitted through the driveline.

Driveline torque and/or thrust sensor

A cable tension tester including a hang-on device having spaced clamping rollers and a central tang for bending the cable by lateral displacement through a predetermined departure .DELTA. from a straight line. A load cell connected to the tang measures the force required to maintain the departure. The tester comprises a frame, a slide body for clamping and bending the cable, a lever-type actuator and a spring connecting the actuator to the slide body so as to avoid local flattening of large diameter cables. In the illustrated form, the tester is part of a motor vehicle brake cable tension adjuster including a controller having one or more comparators for comparing measured tension to tension reference values. A difference signal is applied to a control valve to operate an air wrench which turns a nut on a tension adjustment shaft while the parking brake pedal is maintained in a fixed position.

Cable tension tester and control system

A weigh scale apparatus in which forces caused by the applied load are transformed into moments of opposite sense and applied to opposite ends of a substantially rigid beam. Deflection of the beam is measured by centrally disposed strain gage resistors to produce an electrical signal quantity proportional to the applied load. The conversion of applied load to moments of opposite sense is accomplished by a pair of spaced parallel pivot members which are suspended by straps between the load receiving pan and the base such that the pivots tend to rotate in opposite directions. The beam is mechanically connected between the pivots such that it is subjected to the bending moment over substantially its entire length. A split scale device is provided by a composite pan, one portion of which is connected to the pivots directly and another portion of which is connected to the pivots through long lever arms to provide moment multiplication. A vibrator device for dithering the pivots is provided.

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Farmington Hills, MI, United States of America

Ralph S Shoberg