US 5,178,046 AGranted

Screw fastening device

AssigneeTeijin Seiki Co., Ltd.

InventorsKazuyuki Matsumoto, Akio Hashimoto

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Abstract

A screw fastening device comprising a casing, a motor connected to the casing, a block body rotatably housed in the casing and having a pair of axially spaced plate portions, a plurality of torque transmitting pins each rotatably supported on the plate portions of the block body, the pins having eccentric cam portions, respectively, and being rotated by the motor, an externally toothed gear formed with engagement portions engaged by the eccentric cam portions of the torque transmitting pins, an internally toothed gear fixedly mounted in an inner periphery of the casing so that it can engage with the externally toothed gear, the internally toothed gear being slightly different in number of teeth from the externally toothed gear, and a rotational output shaft connected to either one of the plate portions of the block body. The externally toothed gear is given an eccentric motion and rotated by the rotations of the torque transmitting pins, and the block body is rotated by the rotation of the externally toothed gear.

Claims10

Dependent claims

A screw fastening device comprising:

a casing;
a motor connected to said casing;
a block body rotatably housed in said casing and having a pair of axially spaced plate portions;
a first set of needle roller bearings provided between one plate portion of said block body and said casing and a second set of needle roller bearings provided between the other plate portion of said block body and said casing;
a plurality of torque transmitting pins each rotatably supported on said plate portions of said block body, said pins having eccentric cam portions, respectively, and being rotated by said motor;
externally toothed gear means formed with engagement portions engaged by said eccentric cam portions of said torque transmitting pins;
an internally toothed gear fixedly mounted in an inner periphery of said casing so that it can engage with said externally toothed gear means, the internally toothed gear being slightly different in number of teeth from said externally toothed gear means;
said externally toothed gear means being given an eccentric motion and being rotated by the rotations of said torque transmitting pins;
said block body being rotated by the rotation of said externally toothed gear means through said torque transmitting pins;
and
a rotational output shaft connected to either one of said plate portions of said block body for fastening screws.

8 more elements

A screw fastening device comprising:

a casing;
a motor connected to said casing;
a block body rotatably housed in said casing and having a pair of upper and lower plate portions;
a first set of needle roller bearings provided between said upper plate portion of said block body and said casing;
a plurality of torque transmitting pins each rotatably supported on said plate portions of said block body, said pins having eccentric cam portions, respectively, and being rotated by said motor;
externally toothed gear means formed with engagement portions engaged by said eccentric cam portions of said torque transmitting pins;
an internally toothed gear fixedly mounted in an inner periphery of said casing so that it can engage with said externally toothed gear means, the internally toothed gear being slightly different in number of teeth from said externally toothed gear means;
said externally toothed gear means being given an eccentric motion and being rotated by the rotations of said torque transmitting pins;
said block body being rotated by the rotation of said externally toothed gear means through said torque transmitting pins;
a rotational output shaft connected to said lower plate portion of said block body for fastening screws;
and
a mounting bearing undergoing thrust load only that is provided between said rotational output shaft and said casing.

9 more elements

Dependencies are inferred from the claim text.