Gear cutting – milling – or planing – Milling – Including means to infeed rotary cutter toward work
Reexamination Certificate
1999-09-30
2001-03-20
Briggs, William (Department: 3722)
Gear cutting, milling, or planing
Milling
Including means to infeed rotary cutter toward work
C409S211000, C409S216000, C409S235000, C901S041000
Reexamination Certificate
active
06203254
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a machining device utilizing a parallel mechanism for supporting a tool using a plurality of link mechanisms.
2. Description of the Related Art
Machine tools to which a parallel mechanism is applied have been developed. Most of the machining devices adopt a structure referred to as “Stewart platform” structure.
The outside view of a parallel mechanism machining device of ordinary Stewart platform structure is shown in FIG.
7
and the typical view thereof is shown in FIG.
8
. In
FIG. 8
, each of adjustable joints
41
(
41
a
to
41
f
) supporting six links
40
(
40
a
to
40
f
) at a movable body
20
side has a constitution shown in, for example,
FIG. 9
that the rotary shaft thereof is supported by an anti-friction bearing.
In addition, each of adjustable joints
42
(
42
a
to
42
f
) supporting six links at a fixed platform
34
side has a constitution shown in, for example,
FIG. 10
that the rotary shaft thereof is supported by an anti-friction bearing. The links, which are, for example, ball springs, are extensible by rotating nuts by a servo motor. In
FIG. 8
, reference symbol
19
denotes a table and
21
denotes a tool.
The above-stated Stewart platform structure is characterized in that the structure is simple and has high rigidity of the structure in Z-axis direction (tool rotation axis direction in FIG.
8
). Since the movable body
20
serving as a platform is protruded from the fixed base
34
, its rigidity in X and Y axis directions is low. Since the table
19
is fixed to the lower surface, the structure has disadvantageously bad chip removal property.
BRIEF SUMMARY OF THE INVENTION
The present invention has been made under the circumstances. The object of the invention according to a first embodiment is, therefore, to realize a parallel mechanism machining device of structure having high rigidity in any direction and the object of the invention according to a second embodiment is to realize a parallel mechanism machining device having good chip removal property.
To obtain the above objects, the invention according to the first embodiment is constituted as a parallel mechanism machining device supporting a movable body holding one of a main shaft for rotating a tool and a work so that the movable body can be moved relative to the other one of the main shaft and the work by a plurality of link mechanisms connected to the movable body by adjustable joints, respectively, the device comprising two first links each having one end connected near a point on the movable body; two second links each having one end connected near a point other than the point on the movable body; a third link extending almost parallel to a straight line passing a connection between the first links and the second links; and a restriction link restricting degree of freedom of movement of the movable body, wherein the other ends of the links are supported by a surrounding fixed platform through adjustable joints, respectively, and the two links of each of the first and second links have about 90 degrees with each other to allow a state in which the respective links extend in a direction almost orthogonal to the third link.
The invention according to a third embodiment is constituted as the parallel mechanism machining device according to the first embodiment, and further including that the two links of at least one of the first links and the second links are connected to the movable body by forked adjustable joints, respectively.
Each of the forked adjustable joints may consist of a circular arc guide rotatable on an attachment surface on which the joint is attached to the movable body, a ring body guided by the circular ark guide and rotatable on a surface orthogonal to the attachment surface, a bearing provided at a center of the ring body and rotatable on a surface orthogonal to both of the attachment surface and the surface orthogonal to the attachment surface, two links connected to the forked adjustable joint through the bearing.
According to a further feature, the invention according to the disclosed embodiments may include a circular table rotating while fixing the work, whereby a direction of the main shaft of the movable body can be changed from a direction of a rotation center line of the circular table to a direction perpendicular to the rotation center line.
According to the second embodiment of the invention, the circular table is provided with an inclination mechanism, whereby the circular table can be both placed horizontally and inclined by not less than 20 degrees with respect to a horizon.
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patent: 5715729 (1998-02-01), Toyama et al.
patent: 5787758 (1998-08-01), Sheldon
patent: 5906461 (1999-05-01), Lunz et al.
patent: 5919014 (1999-07-01), Weck et al.
patent: 2179605 (1987-03-01), None
patent: 1296-401 (1987-03-01), None
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Internet printout, Titled “Les robots a mouvements spatiaux/Spatial robots”, internet address http://www-sop/inria.fr/saga/personnel/merlet/Archi
ode2.html, Apr. 2000.
Matsushita Tetsuya
Nakagawa Masao
Nashiki Masayuki
Watanabe Shigeharu
Briggs William
Ergenbright Erica
Okuma Corporation
Pearson & Pearson
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