Precision force applicator for force transducer calibration
Inventors
Schulz, Bradley Dean • Krueger, Paul M.
Assignees
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Publication Number
US-9696229-B2
Publication Date
2017-07-04
Expiration Date
Abstract
A force applicator assembly is disclosed to calibrate an in-situ force transducer (or load cell) in a force (load) applying test machine. The force applicator includes stationary member configured to be secured to fixed structure, a moving member, a load cell operably coupled to an end of the moving member, and a differential screw assembly connecting the moving member to the stationary member. A coupling assembly can be used to assure that only tension or compression loads are applied. The coupling assembly can be configured if desired such that no tension or compression loads can be applied. A method to calibrate an in-situ force transducer in a force applying test machine is also provided and uses a force generator and the coupling assembly.
Core Innovation
The invention provides a coupling assembly to couple a first element to a second element to transfer linear compression and/or tension forces. The coupling assembly includes a retainer assembly connectable to the first element, where the retainer assembly has a first three dimensional curved surface and a second three dimensional curved surface spaced apart from and facing the first three dimensional curved surface. A reaction structure is connectable to the second element and is disposed between the first and second three dimensional curved surfaces.
The reaction structure and the spacing between the first and second three dimensional curved surfaces are configured such that movement of the second element causes the reaction structure to contact only one of the first or second three dimensional curved surfaces at a time when transmitting forces from the second element to one of the first and second three dimensional surfaces. In one arrangement, the facing curved surfaces are defined using partially spherical surfaces, including convex partially spherical surfaces that protrude toward each other.
The coupling assembly is further configured to align an axis of the first element with an axis of the second element when forces are transferred through the coupling assembly. Configurations described in the document further include a retainer assembly with opposed apertures through which the reaction structure extends, and geometry refinements in which the reaction structure includes opposed concave surfaces that each engage a corresponding three dimensional curved surface.
Claims Coverage
The partial content includes two independent claims (clm-00001 and clm-00012). Each independent claim centers on a coupling assembly that transfers linear compression and/or tension forces using a reaction structure disposed between two spaced, facing three-dimensional curved surfaces, with contact constrained to only one curved surface at a time during force transmission; the second independent claim additionally specifies axis alignment and convex partially spherical surface geometry.
Three-dimensional curved surfaces with selective contact of the reaction structure
A retainer assembly connectable to the first element having first and second three dimensional curved surfaces spaced apart from and facing each other, and a reaction structure connectable to the second element disposed between the first and second three dimensional curved surfaces, wherein the reaction structure and the spacing are configured such that movement of the second element causes the reaction structure to contact only one of the first or second three dimensional curved surfaces at a time when transmitting forces.
Convex partially spherical surfaces and axis alignment during force transfer
A retainer assembly connectable to the first element with a first convex partially spherical surface and a second convex partially spherical surface spaced apart from and facing the first convex partially spherical surface, with both convex partially spherical surfaces protruding toward each other; a reaction structure connectable to the second element disposed between the first and second convex partially spherical surfaces, wherein the reaction structure and the spacing are configured such that movement of the second element causes the reaction structure to contact only one of the first or second convex partially spherical surfaces at a time; and wherein the coupling assembly is configured to align an axis of the first element with an axis of the second element when forces are transferred.
Across the two independent claims, the core claim coverage is the same contact-selective coupling concept using spaced, facing three-dimensional curved surfaces and a reaction structure that contacts only one surface at a time during compression/tension force transmission; the second independent claim narrows the geometry to convex partially spherical surfaces and adds axis alignment of the first and second elements.
Stated Advantages
Not explicitly described in patent.
Documented Applications
Not explicitly described in patent.
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