Machine element or mechanism – Gearing
Reexamination Certificate
2001-04-06
2002-11-12
Estremsky, Sherry (Department: 3681)
Machine element or mechanism
Gearing
C475S149000
Reexamination Certificate
active
06477918
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to an actuator suitable for an apparatus popularly known as a “universal head”, mainly for three-dimensionally positioning of a monitoring camera, a disco-lighting unit, an antenna drive unit, a (multi-axis multi-articular) robot, or the like, particularly to a rotary electric machine having a coaxial output hollow shaft with a reduction gear and a slip ring.
In such an apparatus called a universal head mainly for three-dimensionally positioning a monitoring camera, a disco-lighting unit, an antenna drive unit, a multi-axis (multi-articular) robot, or the like, a panning (horizontally rotating) motor and a tilting (vertically rotating) motor are used for three-dimensional positioning by an actuator. Usually the tilting motor is horizontally rotated by the panning motor, and a camera or a light attached to the tilting motor is positioned in a desired three-dimensional position.
According to the configuration of such a three-dimensionally positioning apparatus in the related art, power supply lead wires for the tilting motor or power supply cables for the camera or the light may be twisted or the camera or the light cannot be rotated continuously when the camera or the light is driven. Thus, for example, there is a demerit in that the camera or the light cannot be moved and rotated over a limited angle of about 300°.
Therefore, the present inventor has filed an application for a patent titled “Direct Drive Electric Motor Apparatus Incorporating Slip Ring Assembly” as Japanese Patent Application No. 284695/1998, and thereafter submitted a translated document. A description is set forth below about this related-art direct drive apparatus with reference to FIG.
3
.
A television camera apparatus
101
shown in
FIG. 3
is constituted by a well-known dome-shaped camera enclosure
103
used in a monitoring system; a transparent or semi-transparent dome
103
A; a base plate
104
which is fixedly attached to the upper portion of the camera enclosure
103
; a panning motor
102
which is fixedly attached to the surface of the base plate
104
; a camera holder bracket
107
attached to a rotor
114
of the panning motor
102
disposed so as to be rotatable around the horizontal axis H (pan) which extends through the center of the base plate
104
and which is orthogonal to the base plate
104
; and a tilting motor
110
fixedly mounted on one side of the camera holder bracket
107
which is formed as an inverted U-shaped fork-like holder.
A television camera
112
is attached to a rotor
116
of the tilting motor
110
, so that the camera
112
is mounted so as to be rotatable around the vertical axis V (i.e. tilt axis). On the opposite side, the camera
112
is mounted on the camera holder bracket
107
via a well known pivotally rotating joint
115
extended along the V axis.
The V axis (tilting axis) which is orthogonal to the H axis (panning axis), the L axis (lens) which is orthogonal to the V axis (tilt), and the H axis (panning axis) are made to intersect each other at the center of the dome-shaped cover portion
103
A so as to provide the all-round unobstructed panning and tilting movement within the dome sphere.
The panning motor
102
incorporates rotary contacts or a slip ring assembly
106
inside its rotor
114
.
The slip ring assembly
106
per se is a known assembly constituted by a rotating conductive metal ring, and a complementarily mounted conductive metal brush that applies pressure to the metal ring for holding a continuous current flow through the metal ring during the rotation of the metal ring.
Connecting wires
105
include wires for feeding power and control signals to the camera and wires for receiving a video signal, an audio signal and data signals from the camera. The connecting wires
105
pass through an opening in the domed closure or case
103
and the base plate
104
for connecting the rotating ring of the slip ring assembly
106
.
Wires
113
for feeding power to the panning motor
102
may be fed through a separate opening
113
A directly to the panning motor
102
if the panning motor
102
is an inner rotor type, or the wires
113
should be connected to the panning motor
102
along with the connecting wires
105
if the panning motor
102
is an outer rotor type.
Wires
108
connected at their one ends to the brush of the slip ring assembly
106
are fed through an opening in the holder bracket
107
and are connected at their other ends to the rotating ring of a slip ring assembly
109
mounted on a portion inside the shaft of the rotor
116
of the tilting motor
110
. Wires
111
connected at their one ends to the brushes of the slip ring assembly
109
are connected at their other ends to the camera
112
and to a control circuit (not shown).
It is obvious from
FIG. 3
that, in this arrangement, the camera can rotate endlessly around its panning H axis or its tilting V axis without causing the wires to flex or twist.
Furthermore, it is obvious that the camera holder bracket
107
, which is mounted directly onto the rotor
114
of the panning motor
102
, is directly driven by the drive motor without any power transmission mechanism.
Similarly, it is obvious from
FIG. 3
that the rotor
116
of the tilting motor
110
can directly drive the camera tilting position without using any power transmission mechanism.
The elimination of the power transmission mechanism and assemblies reduces the size of the dome-shaped camera enclosure
103
, simplifies the configuration, improves the efficiency and accuracy of the positioning device, and also improves the reliability.
Incidentally, specific configurations of the panning motor
102
and the tilting motor
110
are shown in detail in the specification and translated document of Japanese Patent Application No. 284695/1998 which is an application according to the above-mentioned related art.
As a result of investigation carried out after filing the application of the above-mentioned related art, however, it was found that there was a problem when a stepping motor suitable for positioning was used as the motor for direct driving without using any reduction gear. That is, it was difficult to start up if load inertia was large. Therefore, a large motor was required, so that the apparatus became unfavorably high in price and large in size in spite of no reduction gear.
SUMMARY OF THE INVENTION
It is therefore an object of the present invention to solve the foregoing problem, and to provide a rotary electric machine having a coaxial output hollow shaft with a reduction gear and a slip ring, which constitute an actuator optimum for and practical in use as a three-dimensionally positioning apparatus for a monitoring camera, a disco-lighting, an antenna, etc.
In order to attain the above object, according to a first aspect of the present invention, that is as defined in claim
1
, there is provided an inner rotor type rotary electric machine having a coaxial output hollow shaft with a reduction gear and a slip ring, comprising: a hollow rotation shaft; a reduction gear for reducing an output of the inner rotor type rotary electric machine and extracting an output through a hollow shaft of the reduction gear coaxially with the hollow rotation shaft; and a slip ring provided in a hollow portion or an output portion of the reduction gear.
According to a second aspect of the present invention, that is as defined in claim
2
, there is provided an outer rotor type rotary electric machine having a coaxial output hollow shaft with a reduction gear and a slip ring, comprising: a hollow rotation shaft; a reduction gear for reducing an output of the outer rotor type rotary electric machine and extracting an output through a hollow shaft of the reduction gear coaxially with the hollow rotation shaft; and a slip ring provided in a hollow portion or an output portion of the reduction gear.
According to the above-mentioned first or second aspect of the present invention, the rotary electric machine is a stepping motor.
According to the above-mentioned first or sec
Estremsky Sherry
Japan Servo Co. Ltd.
Oblon & Spivak, McClelland, Maier & Neustadt P.C.
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