Gear cutting – milling – or planing – Milling – Randomly manipulated – work supported – or work following device
Reexamination Certificate
1999-03-09
2001-05-01
Briggs, William (Department: 3722)
Gear cutting, milling, or planing
Milling
Randomly manipulated, work supported, or work following device
C279S062000, C279S150000, C408S240000
Reexamination Certificate
active
06224304
ABSTRACT:
FIELD OF INVENTION
This invention relates to a bit attaching arrangement for a power tool, and more particularly to an arrangement that allows the bit to be attached without the use of external wrenches or keys.
BACKGROUND OF THE INVENTION
Power tools, such as routers, often incorporate a collet for holding the shank end of a bit in place on the lower end of the rotating armature/output shaft. In particular, the collet consists of a generally cone-shaped structure having a split end which defines separate prongs which are usually biased slightly radially outwardly. The end of the collet opposite the prongs is generally attached to or formed integrally with the output shaft of the router. A router locking nut is used to secure a bit onto the output shaft. The collet nut has a female thread surface which engages the male thread surface located on the lower end of the output shaft. The collet nut fits over the collet and has a female cone-shaped camming surface for engaging the cone-shaped outer surface of the collet.
In order to attach a bit to a router utilizing this well-known structure, the shank of the bit is positioned between the prongs of the collet with the collet nut in a loosened position on the output shaft. After the shank of the bit is completely disposed within the hollow output shaft, the collet nut is tightened such that the prongs of the collet engage the side surfaces of the shank and firmly hold the bit in place on the lower end of the shaft. In order to sufficiently tighten the collet nut so as to secure the bit, external and separate tools and/or wrenches are typically utilized. In particular, the tightening operation of this prior art structure often involves utilizing a shaft lock arrangement which prevents rotation of the output shaft of the router and thereafter allows manual tightening of the nut using a dedicated individual wrench which is often included with the router when it is sold.
This prior locking arrangement suffers from numerous disadvantages. First, because the tightening wrench is a separate item, it is often lost or misplaced after the router has been used for a period of time. This often results in an operator utilizing a nondedicated wrench or pliers to tighten the collet nut. Use of an incorrect sized wrench or pliers may result in damage to the collet nut and/or locking arrangement. Additionally, use of a nondedicated wrench can also result in the collet nut not being sufficiently tightened causing slippage between the bit and the output shaft.
A further disadvantage is the amount of time it takes to replace a router bit. More specifically, to adequately tighten the collet nut, it requires numerous placement and replacement of the wrench on the collet nut to tighten the nut. This is due to limited access to the attaching arrangement through the guards and support plates of the router. Still further, as mentioned above, to rotate the nut with respect to the output shaft, oftentimes there is a shaft-locking mechanism disposed internally within the assembly. This can result in a further disadvantage because of the possibility of the shaft-locking mechanism malfunctioning and impeding the rotation of the output shaft.
Therefore, a bit-locking arrangement is needed which will overcome the problems discussed above.
SUMMARY OF THE INVENTION
Accordingly, it is an object of the present invention to provide a locking arrangement for a power tool which does not require any external wrenches or tools to secure the bit to the output shaft of the power tool.
Another object of the present invention is to provide a locking arrangement which does not require a separate spindle lock for maintaining the outward shaft stationary as the tightening nut of the arrangement is turned.
A still further object of this invention is to provide a bit-locking arrangement which is self-contained within the power tool and which provides for general fixation of the locking member while rotating the output shaft of the power tool to accomplish the tightening and loosening process.
Accordingly, the present invention provides for a bit-attaching arrangement for a power tool wherein the power tool has a rotatably driven shaft onto which a bit is attached and rotated through the use of a collet. The arrangement includes a collet nut threadably engaging the shaft. The collet nut has a plurality of slots positioned on an outer peripheral wall. A first gear is disposed on the shaft so that rotation of the first gear causes rotation of the shaft. An actuating member has a second gear and a slot engaging extension. The actuating member is positionable between a first position and a second position. In the first position, the second gear engages the first gear and the extension engages one of the slots. Upon rotation of the actuating member, the shaft will rotate and the collet will be maintained at a generally fixed rotational location, thus allowing loosening and tightening of a bit. In the second position, the first and second gears do not engage one another, and the extension does not engage one of the slots so that the shaft can be freely rotated during the powered operation of the tool.
The invention further includes the actuating member having a knob for rotation of the second gear. The actuating member is disposed in an aperture formed in the housing of the power tool. A button is disposed on the peripheral surface of the knob and is connected to a flange member that abuts a portion of the housing adjacent the aperture when the actuating member is in its second position. In order to orient the actuating member to its first position, the button is depressed to allow the flange to pass within the aperture, and thus to move the actuating member to its first position.
Additional objects, advantages, and novel features of the invention will be set forth in part in the description that follows, and in part will become apparent to those skilled in the art upon examination of the following, or may be learned by practice of the invention.
REFERENCES:
patent: 1489976 (1924-04-01), Brown
patent: 1816239 (1931-07-01), Hamersveld et al.
patent: 1874888 (1932-08-01), Burrell
patent: 2211216 (1940-08-01), Oster
patent: 2387981 (1945-10-01), Davis
patent: 2483662 (1949-10-01), Niederhiser
patent: 2807732 (1957-09-01), Kurtovich
patent: 2897302 (1959-07-01), Godfrey et al.
patent: 3008723 (1961-11-01), Caldwell
patent: 3443479 (1969-05-01), Hawley et al.
patent: 3447001 (1969-05-01), Zelik
patent: 3487747 (1970-01-01), Burrows et al.
patent: 3587387 (1971-06-01), Burrows et al.
patent: 3728038 (1973-04-01), Gage
patent: 3767948 (1973-10-01), Batson
patent: 3811361 (1974-05-01), Seely et al.
patent: 3882758 (1975-05-01), Muller
patent: 4324512 (1982-04-01), Siroky
patent: 4386879 (1983-06-01), Martinmaas
patent: 4389146 (1983-06-01), Coder
patent: 4400995 (1983-08-01), Palm
patent: 4461330 (1984-07-01), Judkins
patent: 4526497 (1985-07-01), Hatfield
patent: 4536113 (1985-08-01), Hatfield
patent: 4652187 (1987-03-01), Regelsberger et al.
patent: 4682918 (1987-07-01), Palm
patent: 4718797 (1988-01-01), Purviance
patent: 4804048 (1989-02-01), Porth, Jr.
patent: 4915555 (1990-04-01), Smothers
patent: 5030044 (1991-07-01), Eros
patent: 5191968 (1993-03-01), McCurry
patent: 5342154 (1994-08-01), Holzer
patent: 5496139 (1996-03-01), Ghode et al.
patent: 5531549 (1996-07-01), Fossella
patent: 5620188 (1997-04-01), McCurry et al.
patent: 6042310 (2000-03-01), Campbell et al.
patent: 2157204 (1985-10-01), None
Patent Abstract, No. SU 1484980, dated Jun. 1989.
Smith Allen P.
Wheeler Dale K.
Black & Decker Inc.
Briggs William
Shook Hardy & Bacon L.L.P.
LandOfFree
Bit attaching arrangement for power tool does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Bit attaching arrangement for power tool, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Bit attaching arrangement for power tool will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2515522