Cutting by use of rotating axially moving tool – Tool-support – With tool-retaining means
Reexamination Certificate
1999-02-18
2001-01-23
Bishop, Steven C. (Department: 3722)
Cutting by use of rotating axially moving tool
Tool-support
With tool-retaining means
C279S091000, C279S093000, C408S226000
Reexamination Certificate
active
06176655
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a drill bit having a drill body and a shank connected with the drill body and including a substantially cylindrical guide portion having a least one guide surface, and a locking portion projecting radially beyond the guide portion. The present invention also relates to a chuck for receiving the drill shank.
2. Description of the Prior Art
For forming bores in hard constructional components formed of concrete, stone, steel and the like, a drill bit, such as described, e.g., in German Patent Publication No. 3,744,091 and having a tubular carrier member which is provided in its front, in the drilling direction, end region with an annular cutting element and is provided at its opposite, rear end with a shank, is used. Here and elsewhere, under “drilling direction” is understood the direction in which the drill bit advances when forming a bore. The shank has a guide portion and a locking portion which projects radially beyond the guide portion. The locking portion is provided with a thread which serves for axially fixing the drill bit in a drill chuck. The chuck has an axially displaceable locking sleeve with a mating thread corresponding to the shank thread. After the insertion of the drill shank into the chuck, the shank and, thus, the drill bit is locked in the chuck by completely rotating the locking sleeve several times into its locking position. Because of the thread, the manufacturing of the chunk is expensive.
Accordingly, an object of the present invention is to provide a drill bit with a shank which can be economically produced and which can be rapidly and simply inserted into a chuck.
Another object of the present invention is to provide a chuck for receiving the inventive drill shank.
SUMMARY OF THE INVENTION
These and other objects of the present invention, which will become apparent hereinafter are achieved by providing a drill bit with a shank the locking portion of which has its locking surfaces extending substantially transverse to a longitudinal axis of the drill, and the cross-section of which extending transverse to the longitudinal axis of the drill, is non-circular. The simplified shape of the locking region substantially reduces costs of manufacturing the drill bit.
For manufacturing reasons, the outer contour of the locking portion of the shank is provided, e.g., with at least one indentation. In order to eliminate a complicated alignment of the drill bit relative to the chuck, when the drill, i.e., the drill shank is inserted into the chuck, the outer contour of the locking portion of the shank is provided, e.g., with two indentations uniformly arranged over the circumference of the locking portion of the shank.
Advantageously, the guide region adjoins the locking region in a direction opposite to the drilling direction. This insures that the drill bit, i.e., the drill shank is insertable in the chuck of a drilling tool in a direction opposite to the drilling direction and is withdrawn in the drilling direction. For insuring a precise guidance of the drill shank in the chuck, the guide portion is advantageously provided with two spaced from each other guide surfaces.
In order to prevent an automatic rotation of the drill bit in the chuck, which is in its locking position, advantageously, at least one locking element is provided on at least one of the locking surfaces of the locking portion of the shank. The locking element can be formed, e.g., as an indentation or as a projection provided on the locking surface, or as cam secured on the locking surface.
Preferably, the drill chuck includes a support member having an opening and a first mating surface facing in the drilling direction, and a clamping sleeve arranged transverse to a longitudinal axis of the chuck and axially displaceable relative to the support member. The clamping sleeve has an end region facing in the drilling direction and having an inner diameter a cross-section of which corresponds to the cross-section of the locking portion of the drill shank. The opening formed in the support member has a cross-section which is defined by the first mating surface and which extends beyond the cross-section of the facing in the drilling direction, end region of the clamping sleeve defined by a second mating surface which is located adjacent to the first mating surface. With this chuck, a quick insertion of the drill bit and a precise guidance of the shank in the chuck is achieved.
In addition to good locking characteristics, particularly good guide characteristics are achieved when the opening, which is formed in the support member, has preferably two axial regions located one behind the other, with the region, which is remote from the mouth of the opening and which is defined by the first mating surface, extending, in a transverse direction, beyond the other region.
A seal is provided in the end region of the support member facing in the direction opposite to the drilling direction. In the locking position of the drill chuck, the seal cooperates with a free end of the shank facing in the direction opposite to the drilling direction. To prevent friction between the drill bit, i.e., the shank and the seal during rotation of the shank in the chuck, advantageously, a portion of the support member is formed as a ring which at least partially forms a portion of the support member extending from the mouth of the opening of the support member, and which can be displaced relative to the remaining part of the support member in the direction opposite to the drilling direction against a biasing force of a spring element. In the non-locking position of the chuck, a portion of the ring, which cooperates with the locking portion of the shank, projects beyond the mating surface provided on the support member, so that the free end of the guide portion of the drill shank does not contact the seal during the rotation of the shank in the chuck.
In order to provide for a sidewise support of the shank in the chuck transverse to the radial extent of the shank locking region, advantageously, the ring is at least partially rotated in a circumferential direction relative to the remaining portion of the support member.
In order to achieve an automatic rotation of the drill bit in the non-locked chuck from a release position or a locking position, advantageously, at least one spring member is provided on the ring which projects beyond the outer contour of the ring and is formlockingly engageable with the clamping sleeve.
Rotation of the drill bit relative to the chuck, when the chuck is in its locking position is advantageously prevented by providing at least one locking element on at least one of the mating surfaces. This locking element can be formed as an indentation or as a projection formed on one of the locking surfaces, or as an cam secured on one of the mating surfaces. This locking element provides for a formlocking connection with a locking element provided on the locking portion of the drill shank.
REFERENCES:
patent: 3756737 (1973-09-01), Smith
patent: 4184692 (1980-01-01), Benson et al.
patent: 4234277 (1980-11-01), Benson et al.
patent: 4834596 (1989-05-01), Hollifield et al.
patent: 5257884 (1993-11-01), Stolz et al.
patent: 5429457 (1995-07-01), Asano et al.
patent: 5879544 (1999-03-01), Cassidy
patent: 6000888 (1999-12-01), Hartman
patent: 0169740 (1984-09-01), None
patent: 0157747 (1987-07-01), None
patent: 0157746 (1987-07-01), None
patent: 138465 (1960-01-01), None
Hoyss Franz
Ostermeier Peter
Roth Peter
Bishop Steven C.
Brown & Wood LLP
Hilti Aktiengesellschaft
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