Cutting – Rotatable disc tool pair or tool and carrier – With means to support work relative to tool
Reexamination Certificate
2001-12-05
2004-04-20
Ashley, Boyer D. (Department: 3724)
Cutting
Rotatable disc tool pair or tool and carrier
With means to support work relative to tool
C083S473000, C083S477100, C083S477200, C083S581000
Reexamination Certificate
active
06722242
ABSTRACT:
BACKGROUND OF THE INVENTION
This invention relates to a table saw, particularly to one having a transmission device capable to maintain a fixed tension when the saw blade is moved up or down.
A conventional transmission device of a table saw, as shown in
FIGS. 1 and 2
, includes a rotatable circular saw blade
11
provided in the center of a table
10
for cutting off wood materials passing therethrough. The circular saw blade
11
is directly driven to rotate by a motor
12
fixed in a box, transmitted by a belt
13
. The circular saw blade
11
must have a function of moving up and down to adapt to wood materials of different thickness. To elevate the circular saw blade
11
, only turn around a hand-swinging rod
14
to let its worm
15
at a front end to activate the gear
17
under an elevating plate
16
to move, and, as the circular saw blade
11
is pivoted with the eccentric shaft hole
18
provided on an upper side of the elevating plate
16
, the shaft hole
18
of the circular saw blade
11
will move in a curved direction to form different heights when the elevating plate
16
is rotating.
However, if the circular saw blade
11
arcuately moves upwards, the distance between the shaft hole
18
and the motor
12
becomes relatively long and the belt
13
is tightened. On the contrary, in case the circular saw blade
11
arcuately moves downwards, the distance between them is comparatively short and the belt
13
will become too loose to carry on transmission. Under such a condition, a spring
19
has to be additionally provided beside the motor
12
for to helping push the whole motor
12
outwards so as to permit the belt
13
to have enough tension to carry on transmission. Besides, the tension of the belt
13
is changed by the shifting of the circular saw blade
11
, thus seriously affecting its service life, and the position of the spring
19
has to be adjusted to strengthen its push force after used for a period of time, resulting in increasing trouble to a user.
SUMMARY OF THE INVENTION
The main objective of the invention is to offer a transmission device of a table saw, having a motor and an elevating plate fixed on a base, a first belt connected to a belt pulley at a front end of the motor and to a transfer member, and a second belt connected to the transfer member and to the belt pulley of a circular saw blade. Thus, the first belt and the second belt are activated to rotate and carry on transmission at fixed positions, accordingly improving the trouble of the conventional device that the belt will become loose or tight when the saw blade is moving up or down.
Another objective of the invention is to offer a transmission device of a table saw, capable to keep the tension of the belts unchanged whether the circular saw blade moves up or down so as to prolong the service life of belts.
REFERENCES:
patent: 319395 (1885-06-01), Doane
patent: 1566838 (1925-12-01), Marois
patent: 2299262 (1942-10-01), Uremovich
patent: 2320743 (1943-06-01), Nilsen
patent: 2505958 (1950-05-01), Grierson
patent: 2626639 (1953-01-01), Hess
patent: 2661777 (1953-12-01), Hitchcock
patent: 2784750 (1957-03-01), Thomas
patent: 3011529 (1961-12-01), Copp
patent: 4365530 (1982-12-01), Johnson et al.
patent: 5819625 (1998-10-01), Sberveglieri
patent: 5943932 (1999-08-01), Sberveglieri
Ashley Boyer D.
Troxell Law Office PLLC
LandOfFree
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