Unibit with replacement blade

a technology of unibits and blades, applied in the field of multi-hole size drill bits, can solve the problems of relatively short life, unibits are relatively more expensive than single-size twist drills, and unibits are typically not re-sharpened when

Inactive Publication Date: 2008-02-07
SEELEY SCOTT C
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Benefits of technology

[0004] Accordingly, a unibit with a replacement blade of the invention provides economical refreshing of the many cutting facets of a unibit with a unibit body and replacement blade that is releasably secured to the unibit body by a blade lock without a complicated mechanism. In one preferred embodiment of the invention, a single replacement blade having cutting edges on one or both opposite side edges is secured in a slot in a conical head of a body then are threaded by screws that extend through the body on one side of the slot, then through an opening in the replacement blade, and into the second side of the body the blade can be provided with or without an integral tip drill. The coni

Problems solved by technology

Unibits are relatively more expensive than single size twist drills and tend to be used frequently because of their versatility of being capable of drilling a variety of hole sizes.
This frequen

Method used

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  • Unibit with replacement blade
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  • Unibit with replacement blade

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Experimental program
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first embodiment

[0044] In the first embodiment, a blade receiving recess 40 is formed in each side of the head 30 and releasably receives a corresponding replacement blade 24. As shown in the drawings, the blade receiving recess is a generally V-shaped sectional void in the head 30 that resembles a quarter-section-like portion from the head. This is not a true quarter-section, however, in that the sides or walls 42 and 48 of the section are not aligned (coplanar) with the axis of rotation “A.” Rather, as shown in the end view of the FIG. 5, the plane of side 48 is overextended beyond the axis. The extent of overextension is preferably about the thickness of the replacement blade 24, such that a cutting edge 46 of the replacement blade at a face surface 54 of the blade lies in a plane that extends generally through the axis “A.”

[0045] The replacement blade 24 is a generally triangular shaped plate member that is constructed of a suitably hard material, such as 6264 tool steel, for example. In the fi...

second embodiment

[0049] In the invention, shown in FIG. 6, rather than locking the blade in place with the eccentric cam 60 of FIG. 1, the blade can be locked in place by a blade lock 26′ that includes a cam plate in the form of angle plate 71 that bears against the outside of the blade. A bolt 73 extends through a slot 72 in the angle plate and screws into a threaded, inclined opening 75 in the body of the unibit. Tightening the bolt urges the bolt against an inclined outer surface of the angle plate and causes the angle plate to clamp the blade in position.

third embodiment

[0050] In the invention, shown in FIG. 7, blade lock 26″ includes a screw or bolt 77 that extends into a threaded opening 79 that is parallel with the side of the blade. A cam plate 81 with an inclined side is positioned between the blade and a screw head 83, so that the head of the screw urges the plate against the blade as the screw is screwed into the opening.

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Abstract

A unibit with replacement blade provides economical refreshing of the many cutting facets of a unibit drill bit with a unibit replacement blade that is releasably secured in the unibit body. In one aspect of the invention, a replacement blade with cutting edges on one or both opposite side edges is releasably locked into the unibit body by a transverse locking screw. The blade can be provided with an integral tip drill when desired. In another aspect of the invention, one or more replacement blades is releasably secured in a recess in the unibit body with a simple blade lock mechanism, the blades being positioned symmetrically around the axis of the drill. In one embodiment, the blade lock is an eccentric cam member that rotates into and out of locking engagement with the blade. Other blade locks include clamping screws, screws through the blade, cam plates, tapered blades, and blade receiving grooves. Another aspect of the invention provides a replaceable tip drill.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS [0001] This is a continuation-in-part application of co-pending U.S. patent application Ser. No. 11 / 430,458, entitled Unibit With Replacement Blade and filed on May 9, 2006, by Scott C. Seeley, now co-pending, the disclosure of which is incorporated here by reference.BACKGROUND OF THE INVENTION [0002] The invention relates generally to hole drilling bits that are used to drill holes in sheet metal and other sheet materials. More specifically, the invention relates to a stepped multiple hole size drill bit, which is commonly known as a unibit or step drill. Unibits are relatively more expensive than single size twist drills and tend to be used frequently because of their versatility of being capable of drilling a variety of hole sizes. This frequent use also causes them to have a relatively short life. Further, unibits are typically not re-sharpened when worn because of the level of effort and expense to sharpen their many cutting facets. [0003...

Claims

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Application Information

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IPC IPC(8): E21B10/00
CPCB23B51/009B23B2270/08B23B2251/54B23B51/0411
Inventor SEELEY, SCOTT C.
Owner SEELEY SCOTT C
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