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US 4,491,124 AGranted
Self-tapping duct fitting
OwnerRichard J. Goettelinventor
Life of this patent
Estimating the term…
Abstract
A self-tapping duct fitting (10) in the form of a hollow sleeve having an interrupted cutting edge (20) at a one end (14) so that a hole (68) can be cut in a wall (66) of the duct by a rotative motion of the fitting. Preferably, the interrupted cutting edge (20) includes a plurality of teeth (22) which can form tabs bendable against the inner surface (72) of the duct wall (66) once a hole (68) has been cut in order to retain fitting (10) in place.
Claims10
A self-tapping duct fitting, comprising, in combination:
- (a) a cylindrical hollow sleeve forming a pair of open ends and defining an axis extending between the ends;
- (b) tapping and mounting means at a one of the open ends of said sleeve for cutting a hole into a wall for an associated duct when said sleeve is rotated about the axis defined by said sleeve and for mounting of said sleeve in the cut hole, said tapping and mounting means including a plurality of alternately arranged teeth and separating slots formed axially in said sleeve in substantially equally spaced radial increments about the one of the open ends of said sleeve with each of said slots being narrower than each of said teeth;
- (c) a shield circumscribingly mounted on said sleeve in axially spaced relationship with said tapping and mounting means for sealingly engaging the exterior surface of the wall of the associated duct upon mounting of said sleeve in the hole cut by said tapping and mounting means;
- and
- (d) said sleeve formed of a relatively thin gage deformable metal to provide each of said plurality of teeth with cutting edges and to allow said teeth to be bent over into bearing engagement with the interior surface of the wall of associated duct upon mounting of said sleeve in the hole cut by said tapping and mounting means.
2 more elements
A method of cutting a hole in a wall of a fluid duct and mounting a duct fitting therein comprising the steps of:
- (a) forming a cylindrical hollow duct fitting with an annular interrupted open end edge including an alternately arranged plurality of teeth separated by relatively narrow slots and with an annular shield in spaced relationship with the annular interrupted edge;
- (b) pressing the annular interrupted edge of said duct fitting against a wall of a fluid duct in which said duct fitting is to be mounted;
- (c) rotating said duct fitting about its longitudinal axis so that the interrupted edge thereof cuts a hole through the wall of the fluid duct;
- (d) removing said duct fitting from the cut hole in the wall of the fluid duct to extract the cutout piece therefrom;
- (e) pushing the extracted cutout piece out of the open end of said duct fitting;
- (f) reinstalling the interrupted open end edge of said duct fitting in the hole cut in step c to bring the annular shield of said duct fitting into sealed bearing engagement with the exterior of the wall of the fluid duct;
- and
- (g) bending the teeth of the interrupted edge of said duct fitting into bearing engagement with the interior of the wall of the fluid duct.
5 more elements
Dependencies are inferred from the claim text.