Metal deforming – With use of control means energized in response to activator... – Including plural sensors or sensor responsive to comparison...
Reexamination Certificate
2000-10-25
2003-03-04
Jones, David B. (Department: 3725)
Metal deforming
With use of control means energized in response to activator...
Including plural sensors or sensor responsive to comparison...
C072S031010, C072S213000, C072S389100, C083S209000, C083S370000, C033S203120, C033S751000, C324S206000, C324S214000
Reexamination Certificate
active
06526793
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates primarily to a permanent magnetic marking and positioning system of unfinished metal bars, and more particularly, to a magnetic marking and positioning system, which permits central alignment of a cylindrical steel rod to its longitudinal center or balance point prior to forming in a bending jig.
BACKGROUND OF THE INVENTION
In the manufacture of U-bolts and other related parts, it is common to cut a long steel rod into shorter sections of predetermined length. While each rod section remains straight, each is threaded along the opposite end portions. To produce a U-bolt, each of the threaded straight rods are then successively inserted into a hydraulic or powered bending and forming machine that cold forms each rod around a U-shaped mandrel.
Before performing the bending operation, an operator must place the unbent rod in the bending machine and position it using a tape measure to position it so that the midpoint of the rod is aligned with the center of the mandrel.
When rods of different lengths are being successively formed into U-bolts, it is necessary to readjust the adjustable stops for each rod that is different in length. This requires additional setup time for each group of rods being formed. Still more time is wasted in determining the longitudinal center of the rod, and then positioning it over the center of the mandrel. This manual process is also subject to human operator error due to fatigue.
Visual marking and forming machines used for the production of U-bolts is well known in the prior art. Disclosed are several forming machines that use a variety of longitudinal center marking methods. Examples of such prior art are shown in the patents that follow.
U.S. Pat. No. 4,835,805, granted Jun. 6, 1989, to J. C. Gray, discloses the production of threaded metal rods for making U-bolts, where straight cylindrical metal rods are threaded along opposite ends and the center portion is marked to form a visual indicator of the longitudinal center of the rod. The mark identifying the center of each rod extends circumferentially around the metal rod and is formed by a stripe of color contrasting ink directly to the rod provide a permanent mark that does not require rotating the rod to find the mark. The mid-point mark on each rod is aligned with the center plane mark on the machine and the rod is bent to form a precision U-bolt.
U.S. Pat. No. 4,654,912, granted Apr. 7, 1987, to J. C. Gray, discloses the production of threaded metal rods for making U-bolts, where straight cylindrical metal rods are threaded along opposite ends and the center portion is marked to form a visual indicator of the longitudinal center of the rod. The mark identifying the center of each rod extends circumferentially around the metal rod and is formed by a stripe of color contrasting ink to provide a permanent mark that does not require rotating the rod to find the mark. The mid-point mark on each rod is aligned with the center plane mark on the machine and the rod is bent to form a precision U-bolt.
U.S. Pat. No. 4,572,293, granted Feb. 25, 1986, to J. G. Wilson, et al., discloses a method for placing magnetic markers on collarless cased wellbores. A magnetic marker is used to locate wireline tools in wellbores using collarless housing. The magnetic marker is applied at selected positions on the casing before or after placing casing in a well.
U.S. Pat. No. 4,446,711, issued to Raymond L. Valente on May 8, 1984, discloses and claims a novel improvement for a U-bold bender.
Still another prior art patent, U.S. Pat. No. 4,572,293, issued to Wilson, et al., on Feb. 25, 1986, discloses the use of magnetic depth markers placed at regular vertical intervals for depth of wireline tools during a logging run.
The prior art recited above does not teach of the novel advantages that are found in the present invention. Several teach of using visual stripes using tapes or labels to mark the center of the rod being formed.
Accordingly, it is therefore an object of the present invention to provide a novel positioning means to locate the longitudinal center of a cylindrical steel rod prior to being cut to a desired predetermined length.
It is another object of the present invention to provide a novel magnetic marking means at the longitudinal center of a cylindrical steel rod prior to being cut to a desired predetermined length.
It is still another object of the present invention to provide a novel positioning and longitudinal centering means for a magnetically marked cylindrical steel rod so that it can be formed into a precise U-bolt, having equal and symmetrical ends.
A final object of the present invention is to provide a novel method of marking a cylindrical steel rod, using a permanent non-visual marker, to provide a coded identification of the manufacturer in the event of a catastrophic failure of the entire assembly, such as in an aircraft failure.
These as well as other objects and advantages of the present invention will be better understood and appreciated upon reading the following detailed description of the preferred embodiment when taken in conjunction with the accompanying drawings.
SUMMARY OF THE INVENTION
The present invention relates primarily to a novel permanent magnetic marking and positioning system of unfinished metal bars, which aligns a cylindrical ferrous rod to its longitudinal center point (or balance point) prior to forming in a bending and forming machine.
In one aspect of the present invention, the ferrous rod that is used to manufacture the U-bolts is magnetically marked at its center-point and then cut to the desired length by longitudinally inserting the raw cylindrical rod into a cutoff saw station or machine until it comes in contact with a stop that is set to the desired predetermined length. The frame includes at least one magnetizing head each including an electromagnetic coil. An automatic centering device positions each magnetizing head located at the longitudinal center, on each side, of the rod. While positioned at a midpoint of a secured rod a high energy current pulse is provided across the coil to the rod, thereby magnetically marking the midpoint of the rod with a permanent invisible magnetic mark indicator of a longitudinal center of the rod.
The system is automated, for when the raw cylindrical rod comes in contact with the stop, it closes a switch which results in sending a high energy current pulse to an electromagnetic coil mounted on each magnetizing head, thereby magnetically marking the midpoint of the steel rod prior to being cut to the desired predetermined length. Typically, the pulse is rectangular, having an amplitude in the range of 10 to 50 volts, preferably 24 volts and a duration in the range 10 to 500 milliseconds, preferably at least 100 milliseconds.
After each magnetically marked rod is suitably cut to the desired predetermined length, each of the opposite ends is threaded to the desired thread size.
In another aspect of the present invention, the unbent threaded steel rod is positioned in the hydraulic or powered bending machine, so that the longitudinal center of the rod is aligned to the center of the bending mandrel. A peak magnetic detector is used to locate the magnetic center of the rod. The peak detector gives a visible presentation on a meter, in either digital or in analog form, or even gives an audible ‘beep’ at the located midpoint. A centering indicator having peak magnetic strength detection allows manual or automatic positioning of the rod so that the center of the magnetic mark is perfectly aligned with the center of the bending mandrel. Once the midpoint of the rod is positioned and aligned with the center of the mandrel, the straight threaded rod is formed into a U-bolt.
The magnetic mark remains permanently embedded at the crest of the formed U-bolt, thereby rendering a permanent tag identifying the origin of the U-bolt.
As such, the invention comprises a system for locating and marking a midpoint of unfinished rod stock placed on a support frame, table, workbench or cutoff stati
Danko Donald M.
Taddeo Joseph H.
Jones David B.
Taddeo Joseph H.
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