Woodworking – Rotary cutter
Reexamination Certificate
2001-01-08
2002-03-12
Bray, W. Donald (Department: 3725)
Woodworking
Rotary cutter
C144S134100, C144S135200, C144S137000, C144S219000, C407S031000, C409S234000
Reexamination Certificate
active
06354347
ABSTRACT:
BACKGROUND OF THE INVENTION
Many different aesthetically pleasing doors are made with an open rectangular frame portion formed by a pair of rails and a pair of styles, and a raised panel which is rectangular in shape and has a decorative profile cut into its peripheral edges, with the edges of the raised panel also being formed with a tongue portion that is received in correspondingly shaped grooves cut in the frame.
In conventional cutting methods, there are at least two known techniques for forming the edges of the raised panel with the required decorative profile and the tongue portion. First, it is known to use two separate cutters in two separate cutting steps. In one cutting step, the cutter is shaped to cut the required back cut in the edges of the raised door panel, and in a second cutting step another cutter is used, this cutter being designed to cut the desired decorative profile in the edge of the raised door panel. While this method of forming the edges the raised door panel results in an entirely acceptable raised door panel, it obviously is time consuming in that two separate cutting steps are required.
Alternatively, it is also know to mount both a back cutter and a profile cutter on the same drive shaft to form a router bit that will make both cuts simultaneously, but these router bits also suffer from several disadvantages. More specifically, from an architectural and aesthetically pleasing standpoint, it is preferred that the overall profile formed at the edges of the raised door panel has a total length of one and one-half inch. However, a router bit of this type must have a pilot member disposed between the profile cutter and the back cutter and rotatably mounted on the drive shaft of the router bit so that the exterior cylindrical surface of the pilot member can abut the end face of the edge of the raised door panel and provide a guide to properly determine the length of the profile being formed. Since the pilot member is mounted for rotation on the drive shaft using ball bearing so that it will not rotate with the drive shaft and create unacceptable friction with the abutting end face of the raised door panel, the pilot member has a radial dimension of approximately one-half inch. If the overall radius of the profile cutter is about one and three-quarter inch, the actual length of the profile cut by the router bit will be less than one and one-half of an inch because of the radius of the drive shaft and radius of the pilot member, and this length is obviously less than the preferred length of one and one-half inch as discussed above.
On the other hand, it is generally not feasible to simply increase the radius of the profile cutter to accommodate the radius of the rotating pilot member because the increase in the radius of the profile cutter creates unacceptable risks created by the increased speed at the tip of the profile cutter that can create a potentially dangerous situation for the operator of the equipment.
Thus, it is now common practice to use a router bit which includes both the back cutter and the profile cutter to thereby eliminate the necessity of making two separate cuts, but the result is that the length of the profile is less than the desired one and one-half inch.
In accordance with the present invention, a router bit includes both a back cutter and a profile cutter, and it is still capable of forming a profile of one and one-half inch without increasing the radius of the profile cutter.
SUMMARY OF THE INVENTION
The present invention provides a router bit for forming the edges of a raised door panel which includes a rotatable drive shaft, a profile cutter fixed to the drive shaft for rotation therewith to form a decorative profile at the edge of the raised door panel, and a back cutter fixed to the drive shaft for rotation therewith to simultaneously form a back cut relief in the same edge of the raised door panel. A cylindrically-shaped pilot member is disposed intermediate the profile cutter and the back cutter so that the exterior surface of the pilot member can be in abutment with the raised door panel to properly locate door panel relative to the profile cutter and the back cutter during the cutting of the raised door panel. The pilot member is fixed to the drive shaft for rotation therewith and the exterior surface of the pilot member is coated with a friction-reducing material to reduce or eliminate any significant friction between the exterior surface of the rotating pilot member and the raised door panel.
In the preferred embodiment of the present invention, the friction-reducing material is Teflon, and the back cutter and the profile cutter are shaped to cut a tongue in the edge of the raised door panel so that the end face of the tongue abuts the exterior surface of the rotating pilot member during cutting of the raised door panel.
REFERENCES:
patent: 283678 (1883-08-01), Steele
patent: 2915095 (1959-12-01), Pelto
patent: 5433563 (1995-07-01), Velepec
patent: 5615718 (1997-04-01), Venditto
patent: 5996659 (1999-12-01), Burgess
patent: 6019148 (2000-02-01), Hansen
Amana Tool 2001/2002 Catalog (2 pages).
Sommerfeld's Tools for Wood Catalog (2 pages).
Freud General Products Catalog (6 pages).
Eagle America—Special Millenium Edition Catalog (2 pages).
Bray W. Donald
Freud TMM, Inc.
Kennedy Covington Lobdell & Hickman LLP
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