Woodworking – Planer – Rotary cylindrical cutter
Reexamination Certificate
2001-03-29
2001-10-30
Bray, W Donald (Department: 3725)
Woodworking
Planer
Rotary cylindrical cutter
C144S130000, C083S522190, C409S210000, C409S214000
Reexamination Certificate
active
06308754
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a wood-planing machine, more particularly to a thickness-indicating device for a wood-planing machine, which indicates the thickness of a workpiece to be cut.
2. Description of the Related Art
Referring to
FIGS. 1
,
2
and
3
, a conventional wood-planing machine is shown to include a machine bed
1
(only a portion thereof is shown in FIG.
1
), and a cutter seat
2
disposed vertically and movably on the machine bed
1
. A thickness-indicating device
10
includes a rotatable pointer
11
, a reed spring
12
fixed on the cutter seat
2
, and a scale member
13
. When it is desired to cut a workpiece
100
that is held on the machine, the cutter seat
2
is moved toward the workpiece
100
. During downward movement of the cutter seat
2
, a curved end
121
of the reed spring
12
presses against the workpiece
100
so as to deform, thereby pushing upward a nose
112
of the pointer
11
. A free end
111
of the pointer
11
is thus turned upward, thereby indicating the thickness of the workpiece
100
to be cut. The conventional thickness-indicating device
10
suffers from the following disadvantage:
(1) A linear contact is present between the reed spring
12
and the workpiece
100
, thereby hindering smooth movement of the workpiece
100
between the reed spring
12
and the machine bed
1
, which is performed in order to change the portion of the top surface of the workpiece
100
to be cut.
(2) Because the engaging surface area between the reed spring
12
and the workpiece
100
is relatively large, and because the vibration resulting from cutting of the workpiece
100
is transmitted to the reed spring
12
, the reed spring
12
easily experiences spring fatigue.
(3) Due to the linear engagement between the reed spring
12
and the workpiece
100
, there is a need to exert a relatively large force to depress the cutter seat
2
for deforming the curved end
121
of the reed spring
12
. In a case where the workpiece
100
has a somewhat soft top surface to be cut, a shallow slot (not shown) will be formed in the soft top surface. As such, it is difficult for the pointer
11
to indicate accurately the thickness of the workpiece
100
to be cut. Furthermore, the engagement between the curved end
121
of the reed spring
12
and the shallow slot will prevent movement of the workpiece
100
between the reed spring
12
and the machine bed
1
.
SUMMARY OF THE INVENTION
An object of this invention is to provide a woodplaning machine with a thickness-indicating device, which has a relatively small engaging surface area that contacts a workpiece to be cut, thereby enabling smooth movement of the workpiece relative to the device and accurate indication of the device.
According to this invention, a thickness-indicating device for a wood-planing machine includes a mounting member, a pointer, a vertical pushing rod, a resilient member, and a scale member. The mounting member is adapted to be disposed fixedly on the cutter seat. The pointer has a connecting end that is mounted pivotally on the mounting member, an indicator end that is rotatable about the connecting end, and an abutment portion that is located between the connecting end and the indicator end. The pushing rod is disposed vertically and movably on the mounting member, and has an upper end which abuts against the abutment portion of the pointer, and a lower end which is adapted to abut against a top surface of a workpiece that is held on the machine. The resilient member is adapted to bias a lower end of the pushing rod to abut against the workpiece. The scale member is disposed fixedly on the mounting member near the indicator end of the pointer. Accordingly, when the cutter seat and the mounting member move downward toward the workpiece, the pushing rod cannot move relative to the workpiece so as to rotate the pointer relative to the mounting member and the scale member, thereby indicating the thickness of the workpiece to be cut. Because the engaging surface area between the pushing rod and the workpiece is relatively small, the workpiece can be moved smoothly relative to the pushing rod. Furthermore, formation of any slot or groove in a top surface of the workpiece can be prevented due to the reduction in the engaging surface area.
REFERENCES:
patent: 5795113 (1998-08-01), Wixey et al.
patent: 5967205 (1999-10-01), Welsh et al.
patent: 6262839 (2001-07-01), Wixey et al.
Bray W Donald
P&F Brother Industrial Corporation
Trop Pruner & Hu P.C.
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