Drill bit grinding device

Details Drill bit grinding device Drill bit grinding device

2002-10-15

2003-11-25

Morgan, Eileen P. (Department: 3723)

Abrading

Machine

Rotary tool

C451S179000, C451S231000, C451S215000, C451S375000, C451S287000

Reexamination Certificate

active

06652367

ABSTRACT:

BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates to a grinding device, more particularly to a drill bit grinding device.
2. Description of the Related Art
Referring to
FIGS. 1 and 2
, a commonly used drill bit
10
is shown to include a shank portion
11
, a tip portion
13
opposite to the shank portion
11
, and a body portion
12
between the shank and tip portions
11
,
13
. The tip portion
13
is formed with an apex
134
, two cutting edges
133
defining a tip angle (A) (see
FIG. 15
) therebetween, two diametrically opposed lip portions
132
, and two diametrically opposed flank portions
131
, each of which is formed between a respective one of the cutting edges
133
and a respective one of the lip portions
132
. The body portion
12
is formed with a pair of twisted flutes
121
. Grinding swarfs are discharged via the flutes
121
.
When the tip portion
13
of the drill bit
10
is worn out during the drilling operation, the apex
134
of the drill bit
10
becomes dull such that the drilling effect of the drill bit
10
is diminished and that resistance during a subsequent drilling operation is increased. As such, the flank and lip portions
131
,
132
of the drill bit
10
have to be ground by a grinder (not shown) to sharpen the apex
134
. However, the flank portions
131
are ground to form a sharpened tip angle (A) (see
FIG. 15
) based on a worker's experience such that it is difficult to grind the drill bit
10
to form accurately a standardized tip angle (A) (see FIG.
15
), e.g., at 90°, 118°, 150°, etc.
To overcome the above-mentioned drawbacks, many kinds of positioning devices for the drill bit
10
have been proposed heretofore, the main purpose of which is to position the drill bit
10
adjustably with respect to a grinding surface. However, control of the amount of the drill bit
10
to be ground is neglected by these devices. Furthermore, the structures of these positioning devices are somewhat complicated such that corresponding operations of holding and positioning the drill bit
10
are difficult to conduct. Moreover, since the flank and lip portions
131
,
132
of the drill bit
10
have. to be ground individually, and since the angles between the axis of the drill bit
10
and. the surfaces of the flank portions
131
are different from those between the axis of the drill bit
10
and the surfaces of the lip portions
132
, the position of the drill bit
10
has to be changed four times to complete the grinding operation. Each position change of the drill bit
10
includes the steps of unlocking and locking of the drill bit
10
with respect to a grinding seat (not shown), thereby resulting in a complex grinding operation.
SUMMARY OF THE INVENTION
Therefore, the main object of the present invention is to provide a drill bit grinding device that is easy to operate and that can measure the amount of the drill bit to be ground.
According to this invention, a grinding device includes a rotary grinding wheel having an annular grinding surface, a first grinding seat located in front of the grinding wheel, a sleeve disposed rotatably within a through hole in the first grinding seat, an abrasion measuring device for measuring amount of flank portions of a drill bit to be ground, and a tubular holding unit for holding releaseably the drill bit therein. The holding unit is sleeved on the drill bit, is disposed initially in the abrasion measuring device so as to fix position of the drill bit within the holding unit, and is then transferred into the first grinding seat for grinding the flank and lip portions of the drill bit.


REFERENCES:
patent: 3828480 (1974-08-01), Weng
patent: 4023552 (1977-05-01), Moores, Jr. et al.
patent: 4485596 (1984-12-01), Bernard et al.
patent: 4769955 (1988-09-01), Reiling
patent: 5649853 (1997-07-01), Kuo

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