Photography – Camera detail – Camera element cocking or resetting
Reexamination Certificate
2003-09-15
2004-12-28
Gray, David M. (Department: 2851)
Photography
Camera detail
Camera element cocking or resetting
C396S489000
Reexamination Certificate
active
06835007
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a driving apparatus, shutter apparatus and camera which moves a driven member having a moving load from an initial position of charging to a position of completion of charging against the load.
2. Description of Related Art
A conventional charge mechanism which moves a driven member having a moving load from an initial position of charging to a position of completion of charging against the moving load is constructed in such a way that a lever member
401
rotates about one rotation axis as shown in FIG.
23
.
With reference to
FIG. 23
which is a perspective view showing an entire conventional charge mechanism, the conventional charge mechanism will be explained in detail.
Reference numeral
401
denotes a lever member which is supported in a manner rotatable about an axial portion
402
a
laid on a first base plate
402
as the rotation axis, pressed in the thrust direction of the axial portion
402
a
by a dropout prevention member (not shown) with a tiny gap. Reference numeral
401
a
denotes an input side arm portion of the lever member
401
,
401
b
denotes an input pin laid in an integrated fashion on the input side arm portion
401
a
and
401
c
denotes an output side arm portion of the lever member
401
.
Reference numeral
403
denotes a driven member, which is supported in a manner rotatable about an axial portion
402
b
laid on the first base plate
402
as the rotation axis, pressed in the thrust direction of the axial portion
402
b
by a dropout prevention member (not shown) with a tiny gap. At one end of the driven member
403
, the axial portion
403
a
is laid in an integrated fashion and a roller
404
is attached in a manner rotatable about the axial portion
403
a
as the rotation axis. The dropout prevention member (not shown) acts on the roller
404
in the same way.
Reference numeral
405
denotes a power spring (torsion spring) located on the driven member
403
in such a way as to be coaxial with the axial portion
402
b
and its one end contacts a spring stopper
402
c
laid on the first base plate
402
and its other end contacts a spring stopper
403
b
of the driven member
403
and gives the driven member
403
clockwise torque about the axial portion
402
b
as the rotation axis.
Reference numeral
406
denotes a charge input lever and is supported in a manner rotatable about an axial portion
407
a
as the rotation axis, laid on a second base plate
407
which is placed orthogonal to the first base plate
402
and pressed in the thrust direction of the axial portion
407
a
by a dropout prevention member (not shown) with a tiny gap. Reference numeral
406
a
denotes an input side arm portion of the charge input lever
406
and receives a force Fch which rotates the charge input lever
406
counterclockwise about the axial portion
407
a
as the rotation axis to charge this charge mechanism.
Reference numeral
406
b
denotes an output side arm portion of the charge input lever
406
.
406
c
denotes an output pin laid in an integrated fashion on the output side arm portion
406
b
, which contacts the input pin
401
b
of the lever member
401
and transmits power to the lever member
401
. Reference numeral
408
denotes a return spring, one end of which is supported by a spring stopper portion
407
b
laid on the second base plate
407
and the other end of which is hooked on to a hole
406
d
of the charge input lever
406
. Hereby the return spring
408
gives the charge input lever
406
clockwise torque about the axial portion
407
a
as the rotation axis.
Reference numeral
407
c
denotes a stopper provided on the second base plate
407
which contacts the side of the output side arm portion
406
b
of the charge input lever
406
and blocks the clockwise rotation of the charge input lever
406
by the return spring
408
.
Then, the operation of the conventional charge mechanism in the above described configuration will be explained.
First, when a force Fch is applied to the input side arm portion
406
a
of the charge input lever
406
, the charge input lever
406
rotates counterclockwise about the axial portion
407
a
as the rotation axis. In this way, the input pin
401
b
on the input side arm portion
401
a
is pressed by the output pin
406
c
on the output side arm portion
406
and the lever member
401
rotates clockwise about the axial portion
402
a
as the rotation axis. This causes the output side arm portion
401
c
of the lever member
401
to press the roller
404
against the force of the power spring
405
and rotate the driven member
403
counterclockwise about the axial portion
402
b
as the rotation axis.
Then, charging is finished when the driven member
403
has rotated by a predetermined angle.
Then, the operation of the conventional charge mechanism will be explained in detail with the state of a charging load in operation taken into consideration. The power spring
405
is a torsion spring but it will be expressed as a tensile coil spring in the figures used in the following explanations as required.
FIG. 24
is a plane view of charge mechanism (charge input lever
406
placed on the second base plate
407
, etc., is omitted) indicating the lever member
401
and the driven member
403
placed on the first base plate
402
when charging is started, and both the rotation angle of the lever member
401
(driving member) and the rotation angle of the driven member
403
are 0°.
In the same figure, components have dimensions as indicated in the figure and suppose the rotation moment that the power spring
405
gives to the driven member
403
is k&thgr;1 when charging is started. Here, k denotes a spring constant of the power spring
405
per unit rotation angle when the driven member
403
rotates. Furthermore, &thgr;1 denotes a displacement angle from a free state of the driven member
403
.
F in the figure denotes a force that the input pin
401
b
of the lever member
401
receives from the output pin
406
c
of the charge input lever
406
to balance with k&thgr;1, P10 denotes the force that the roller
404
receives from the output side arm portion
401
c
of the lever member
401
, which is equal to a reaction force by the force of the power spring
405
that the output side arm portion
401
c
of the lever member
401
receives through the roller
404
.
From a balance relationship between forces, the following expressions are obtained. Here, for simplicity of explanation, frictions of various portions are ignored.
(
F
·cos 29.16°)×3.90
=P
10×5.79 (1.1)
(
P
10·cos 54.35°)×10.00
=k&thgr;
1 (1.2)
From expressions (1.1) and (1.2), F=0.292k&thgr;1 is obtained.
Here, suppose k=1[gf/deg](=980[dyn/deg]), &thgr;1=10°. Then, F=2.92[gf](=2860[dyn]) is obtained.
FIG. 25
is a plane view of charge mechanism in a first half charging state after charging has further advanced from the state in FIG.
24
. The rotation angle of the lever member (driving member)
401
is 14° and the rotation angle of the driven member is 10° after charging is started.
In the same figure, components have dimensions as shown in the figure and the rotation moment that the power spring
405
gives to the driven member
403
is k(&thgr;1+10°). Reference character F denotes a force that the input pin
401
b
of the lever member
401
receives from the output pin
406
c
of the charge input lever
406
to balance with k(&thgr;1+10°), P20 denotes a force that the roller
404
receives from the output side arm portion
401
c
of the lever member
401
, which is equal to the reaction force by the force of the power spring
405
that the output side arm portion
401
c
of the lever member
401
receives through the roller
404
.
The following expressions are obtained from the relationship of balance between forces. Here, for simplicity of explanation, frictions of various components are ignored.
(
F
·cos 15.16°)×
Canon Kabushiki Kaisha
Cowan Liebowitz & Latman P.C.
Gray David M.
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