Fatigue-resistance sheet slitting method and resulting sheet
Inactive Publication Date: 2006-02-02
IND ORIGAMI INC CA US
View PDF53 Cites 31 Cited by
Summary
Abstract
Description
Claims
Application Information
AI Technical Summary
This helps you quickly interpret patents by identifying the three key elements:
Problems solved by technology
Method used
Benefits of technology
Benefits of technology
[0022] In one aspect, the present invention is comprised of a sheet of material formed for bending along a bend line and having a plurality of bend-inducing structures configured and positioned to produce bending along the bend line. At least one of the bend-inducing structures, and preferably all of them, have arcuate return portions extending from opposite ends of the bend-inducing structure and returning along the bend-inducing structure toward the other return portion. The return portions each are configured to significantly increase resistance to fatigue resulting from cyclical loads oriented in a direction transverse to the bend line by having arcuate lengths and radii reducing stress concentrations. The bend-inducing structures preferably are slits, grooves or steps which are configured to produce edge-to-face engagement on opposite sides of the bend-inducing structures during bending. Stress concentrations can be reduced by forming the arcuate return portions with a cord length at least approximately twice the thi
Problems solved by technology
A commonly encountered problem in connection with bending sheet material using conventional sheet bending equipment, such as a press brake, is that the locations of the bends are difficult to control because of bending tolerance variations and the accumulation of tolerance errors.
A second bend, however, often is located based upon the first bend, and accordingly, the tolerance errors can accumulate.
Since there can be three or more bends which are involved to create an enclosure or closed structure, the effect of cumulative tolerance errors in conventional prior art bending techniques can be significant.
In most of these prior art sheet bending systems, however, the bend-inducing structures greatly weaken the resulting structure, or the bend-inducing structures do not produce the desired precision in the location of the bends, or both.
The problems of precision bending and retention of strength are much more substantial when bending metal sheets, and particularly metal sheets of subst
Method used
the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
View more
Image
Smart Image Click on the blue labels to locate them in the text.
Viewing Examples
Smart Image
Click on the blue label to locate the original text in one second.
Reading with bidirectional positioning of images and text.
Smart Image
Examples
Experimental program
Comparison scheme
Effect test
examples
[0060]FIG. 6 schematically illustrates a box beam as positioned on a fatigue test stand. The box beams tested each had a square cross-section with a dimension of 4 inches on each side and included a flange 132 which was folded inside one of the sidewalls and secured thereto by fastener assemblies 133, in this case a bolt and nut. The fasteners were placed every 4 inches along the length of the beam, and beam 131 had an overall length of 48 inches. A support assembly 135 was provided proximate each end of beam 131, and forced distributing plates 137 used to avoid local concentrations of stress at support stands 135.
[0061] Beam 131 was loaded at two locations 139 on either side of the center of the beam. The loads were spaced from each other by a distance of approximately 6 inches. Again, load distributing plates were employed at 139, and arrows 141 schematically illustrate that the beam was loaded from a minimum load up to a maximum load. Loading was cycled between minimum and maxim...
the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to view more
PUM
Property
Measurement
Unit
Fraction
aaaaa
aaaaa
Length
aaaaa
aaaaa
Thickness
aaaaa
aaaaa
Login to view more
Abstract
A sheet of material (111) having a plurality of bend-inducing structures (113) configured and positioned to produce bending along a bend line (115). The bend-inducing structures (113) have arcuate return portions (122) extending from opposite ends (121) back along the bend-inducing structures (113) toward the other return portion (122) and each return portion (122) has a length dimension and a radius of curvature reducing stress concentrations. Preferably, the length dimension of the arcuate return portion (122) is in excess of twice the thickness. The lateral distance, LD, to which the bend-inducing structures (113) is formed in the sheet away from the bend line (115) is preferably minimized by small radius arcs (125) which connect the return portions (122) to the remainder of the bend-inducing structures (113). A method of forming a structure (131) from a sheet of material (111) to resist cyclical loading is also disclosed, as is a method to increase the fatigue resistance of a structure (131) formed by bending a sheet of material (111) along a bend line (115) having a plurality of bend-inducing structures (113).
Description
CROSS-REFERENCES TO RELATED APPLICATIONS [0001] This application claims priority to U.S. Provisional Patent Application No. 60 / 587,470, filed Jul. 12, 2004, entitled METHOD FOR INCREASING THE FATIGUE RESISTANCE OF STRUCTURES FORMED BY BENDING SLIT SHEET MATERIAL AND PRODUCTS RESULTING THEREFROM, the entire contents of which is incorporated herein by this reference. [0002] This application is also a Continuation-in-Part Application of U.S. patent application Ser. No. 10 / 672,766, filed Sep. 26, 2003, and entitled TECHNIQUES FOR DESIGNING AND MANUFACTURING PRECISION-FOLDED, HIGH STRENGTH, FATIGUE-RESISTANT STRUCTURES AND SHEET THEREFOR, which is a Continuation-in-Part Application of U.S. patent application Ser. No. 10 / 256,870, filed Sep. 26, 2002, and entitled METHOD FOR PRECISION BENDING OF SHEET OF MATERIALS, SLIT SHEETS FABRICATION PROCESS, now U.S. Pat. No. 6,877,349, which is a Continuation-in-Part Application of U.S. patent application Ser. No. 09 / 640,267, filed Aug. 17, 2000, an...
Claims
the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to view more
Application Information
Patent Timeline
Application Date:The date an application was filed.
Publication Date:The date a patent or application was officially published.
First Publication Date:The earliest publication date of a patent with the same application number.
Issue Date:Publication date of the patent grant document.
PCT Entry Date:The Entry date of PCT National Phase.
Estimated Expiry Date:The statutory expiry date of a patent right according to the Patent Law, and it is the longest term of protection that the patent right can achieve without the termination of the patent right due to other reasons(Term extension factor has been taken into account ).
Invalid Date:Actual expiry date is based on effective date or publication date of legal transaction data of invalid patent.