Metal working – Means to assemble or disassemble – By rotation of work part
Reexamination Certificate
2003-01-16
2004-03-16
Hail, III, Joseph J. (Department: 3723)
Metal working
Means to assemble or disassemble
By rotation of work part
C029S240000, C029S283500
Reexamination Certificate
active
06704985
ABSTRACT:
BACKGROUND INFORMATION
1. Field of the Invention
The invention relates generally to the field of threaded fasteners. More particularly, the invention relates to a threaded insert for repairing threads in a bore. More particularly yet, the invention relates to a tool for installing a threaded insert with locking keys into a tapped bore.
2. Description of the Prior Art
Threaded inserts are commonly used to repair or strengthen tapped bores. For example, it is sometimes necessary to repair threads in a bore because the threads have become stripped or otherwise damaged. Thread repair generally comprises the steps of drilling out the damaged threads, tapping the bore to a larger diameter, and threading a threaded insert into the bore to provide an internal threaded diameter that will receive and securely hold the threaded fastener. Often, a threaded insert is used to strengthen a bore made of material that is otherwise too soft to securely hold a threaded fastener, particularly one that is repeatedly inserted and removed. In this case, a threaded insert of hardened material is inserted into a tapped bore of softer material to provide a rugged and durable threaded bore.
In order to install a threaded insert, the insert is properly aligned with the longitudinal axis of the tapped bore, screwed into the bore, and secured. One conventional method of securing the insert in the bore is to provide the threaded insert with locking keys. The conventional insert generally has two or four locking keys that extend upward from keyways that are evenly spaced around the outer perimeter of the insert. After the threaded insert has been threaded into the bore, the locking keys are driven down into keyways, forcing the keys to bite into material in the insert and in the bore, thereby securing the insert against radial movement. One common difficulty with installing the threaded insert is that the locking keys are relatively slender and are in danger of being bent, splayed, or damaged when the insert is screwed into the tapped bore.
Conventional tools for inserting threaded inserts generally comprise several components that move relative to one another and cooperate together to perform the various operations required to properly install the insert. Such a tool is disclosed by Schron et al. (U.S. Pat. No. 5,617,623; 1997). The tool has a drive means, a body, and a press. The body of the tool has a first end with an external threaded shaft onto which the drive means is threaded and a second end with an external threaded shaft onto which the press is threaded. A sleeve encircles the press and is movable relative to the press. A thrust bearing is assembled on the body above the press. The external threads on the threaded shaft on the second end mate with the internal threads on the repair insert, which is rotated down into the tapped bore until the locking keys on the insert hit against the impact face of the press. The drive means is a handle that is used to rotate the body to thread the insert into the tapped bore. The sleeve is moved longitudinally down toward the insert over the locking keys. The socket of a power tool is then placed on the drive means and a rotational force applied to the drive means, which drives the body, the press, and the insert rotationally, threading the insert into the tapped bore and then forcing the locking keys down into the keyways along the outer side of the insert.
The fact that the threaded insert tool of the type disclosed by Schron et al. is constructed of individual parts, some of which move relative to each other in the process of executing the task of inserting a threaded insert, is a disadvantage. The individual parts must be machined with a relatively high degree of precision to ensure that they will function properly together and they must be assembled. The required manufacturing and assembly processes increase the cost of producing such a tool. A tool that comprises multiple moving or cooperating parts also inherently provides sources of tool failure, the failures arising from worn parts that no longer function properly or contamination between parts that prevents them from moving or cooperating properly. As is generally known, threaded inserts are often used in an environment that is laden with contaminants, such as in a machine shop or a car repair shop, and care must be taken to keep the insert repair tool free of dirt and other contaminants.
A single-body insert tool, such as the tool distributed by the Christopher Company for installing ROCK SOLID INSERTS, eliminates some of the disadvantages of other conventional tools, in that it has no moving or cooperating parts. The tool is a cylindrical body with a strike end and an insertion end. A pilot extends from the insertion end for guiding the tool onto the threaded insert. Keyways are provided around the outer perimeter of the insertion end for receiving the locking keys of the threaded insert. A continuous circular groove, concentric to the pilot, is machined into the face of the insertion end. The threaded insert is placed over the pilot such that the locking keys of the threaded insert are secured in the tool keyways. The insert is screwed into the tapped bore, the insert tool lifted slightly and rotated about its longitudinal axis so that the upper ends of the locking keys slide into the groove. An impact force is applied to the strike end of the tool to drive the locking keys into the keyways provided on the threaded insert. Once the tool has been forced down onto the threaded insert as far as it can go, the tool is lifted from the insert. At this point, the upper ends of the locking keys protrude upward beyond the upper edge of the threaded insert. In order to drive the locking keys flush with the upper edge of the insert, the endface of the pilot is placed on a locking key and an impact force applied to the strike end of the tool. Typically, a threaded insert has four locking keys, and the step of driving the locking key flush with the upper edge of the insert is repeated for each locking key.
The disadvantage of the conventional single-body tool is that each locking key must be driven down into the tapped bore individually. This requires repetitive installation steps and also increases the risk that the person installing the insert will accidentally pinch or injure himself during the installation. A further disadvantage of this tool is that it does not correct for a misalignment of the locking key. A misaligned key makes it very difficult, if not impossible, to drive the key properly into the keyway on the insert in the tapped bore.
What is needed, therefore, is a threaded insert tool that provides a means of inserting a threaded insert with locking keys into a tapped bore while simultaneously protecting the locking keys. What is further needed is such a device that corrects a misalignment of the locking keys. What is yet further needed is such a device that simultaneously drives all the locking keys completely into the threaded insert.
BRIEF SUMMARY OF THE INVENTION
It is an object of the present invention to provide a threaded insert tool that properly aligns and inserts a threaded insert into a tapped bore, while simultaneously protecting the locking keys from damage. It is further an object to provide such a tool that corrects a misalignment of the locking keys. It is a yet further object to provide such a tool simultaneously drives all the locking keys completely into the threaded insert so that the upper ends of the keys are flush with the upper edge of the insert.
The objects are achieved by providing a single-component threaded insert tool. The threaded insert tool according to the invention comprises a body with an insertion end for threading the insert into a threaded bore and a strike end for receiving impact blows. The insertion end of the tool has an insertion face, tool keyways evenly spaced around the outer perimeter of the insertion end. A cylindrical pilot or guide extends from the insertion end, coaxial to the longitudinal axis of the tool, and guides the tool into the insert. Key
Bohan Thomas L.
Hail III Joseph J.
Mathers Patricia M.
Shanley Daniel
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