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Description  |
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[FIELD OF THE INVENTION]
The present invention relates to a tripod head. More particularly, the
present invention relates to a tripod head having an excellent
operability, which permits a smooth vertical tilting and a horizontal
rotation of a camera, a video camera, a movie camera or the like under the
effect of appropriate braking force and righting moment, and allows simple
and easy mounting thereof.
[DESCRIPTION OF THE PRIOR ART]
As a device for securing a camera, a video camera, a movie camera or the
like as well as for ensuring smooth and free vertical tilting and
horizontal rotation, a tripod head has been conventionally known, and
various structures and configurations for such a tripod head have been
proposed.
As a typical tiltable tripod head, one which a weight balancer is provided
at a tilting portion to generate a righting moment around the rotating
shaft against a tilting moment produced by the weight of the device such
as a camera so as to give a smooth tilting has been proposed (Japanese
Patent Provisional Publication No. 57-83,791, Japanese Patent Publication
No. 63-9,154).
In this weight balancer, a plurality of independent force accumulators
having a spring member such as a coil spring are parallel supported at the
rotation shaft, and each of those is engaged on its outer peripheral
surface by means of an engaging device mainly comprising a check pin and a
cam mechanism to permit a selective connection between the fixed and the
rotating portions. It thus permits tilting in response to the weight of
the device mounted on the tripod head by selecting an appropriate force
accumulator producing a desired righting moment.
As a tripod head permitting free tilting and horizontal rotation, the
present inventor has proposed a braking device substantially comprising a
first unit in which a plurality of first braking regulation plates and a
plurality of first intermediate members are in turn provided on the
rotation shaft and are concentrically fixed to said rotation shaft, a
second unit in which a plurality of ring-shaped second intermediate
members and a plurality of second braking regulation plates are provided
corresponding to the first regulation plates and the first intermediate
members of the first unit, respectively, and a viscous fluid provided
between the first and the second units, this braking device being
installed on the tilting portion and the horizontal rotation portion in
order to give smooth tilting and horizontal rotations in response to the
weight of the device mounted on the tripod head (Japanese Utility Model
Provisional Publication No. 2-114,297, U.S. Pat. No. 4,979,709).
In this braking device, on-off switching of braking is made free for a
motion at a desired speed in response to the weight of the device such as
a camera.
A tripod head having a sliding plate device provided at the top to simply
and easily secure the device has been also known.
As a sliding plate device, one permitting well-balanced fixing in response
to the weight of the device mounted thereon has been also proposed by the
present inventor (Japanese Utility Model Provisional Publication No.
2-96,099, U.S. Pat. No. 4,959,671).
This sliding plate is mainly composed of a top plate, a plate support
movably engaging with the top plate, a pressure lock mechanism provided on
the side of the plate support to secure the top plate to the plate
support, a vertically movable stop pin provided on the upper surface of
the plate support which movably engages with a long groove provided
longitudinally at the bottom of the top plate, a stopper provided on the
upper surface of the plate support which engages with a short groove
provided longitudinally at the bottom of the top plate, and a stop pin
removing mechanism for removing the top plate from the plate support.
For the tripod head provided with the weight balancer, the braking device,
and the sliding plate device, further improvements are necessitated for a
satisfactory operability in the actual use and an application for various
devices such as a camera, a video camera or a movie camera.
It is a problem for the weight balancer to simply and easily switch over
the righting moment. It is required for the braking device to change the
braking force in response to the weight of the device mounted on the
tripod head, and to simplify and facilitate the switching operation.
Although the above-mentioned sliding plate device is advantageous to
achieve a well-balanced mounting of the device such as camera, and to
mount or remove the top plate attached the device onto or from the plate
support in the direction of sliding the top plate, there is a problem in
that it is difficult to find the inserting position of the top plate into
the plate support, depending upon the size of the device mounted on the
top plate. There is therefore a strong demand for simply and easily
mounting the top plate attached the device on the plate support.
An object of the present invention is therefore to provide an improved
tripod head which has an excellent operability.
Another object of the present invention is to permit a smooth vertical
tilting and a horizontal rotation of a device such as a camera, a video
camera or a movie camera under the effect of an appropriate braking force
and a righting moment.
The other object is to simply and easily mount the device.
These and other objects, features and advantages of the present invention
will become more apparent upon a reading of the following detailed
description and drawings.
[BRIEF DESCRIPTION OF THE DRAWINGS]
FIG. 1 is a sectional view illustrating an embodiment of the tripod head of
the present invention;
FIG. 2 is a perspective view illustrating an embodiment of a braking unit
and a check pin;
FIG. 3 is a sectional view of FIG. 1 cut along the line X--X;
FIG. 4 is a perspective view illustrating an embodiment of a check pin and
a check pin driving shaft;
FIGS.5(a) and 5(b) are partial sectional views illustrating an embodiment
of the panning braking device;
FIG. 6 is a plane view illustrating an embodiment of a spiral spring
incorporated in the spring unit;
FIG. 7 is a plane view illustrating another spiral spring;
FIGS. 8(a) and 8(b) are a plane view and a sectional view illustrating an
embodiment of a case for the spring unit, respectively;
FIGS. 9(a) and 9(b) are a plane view and a sectional view illustrating
another case for the spring unit, respectively;
FIGS. 10(a) and 10(b) are a plane view and a sectional view illustrating an
embodiment of the righting moment switching mechanism of the weight
balancer, respectively;
FIG. 11 is a plane view illustrating an embodiment of a cover and a check
pin;
FIG. 12 is a development of the check pin driving cap shown in FIG. 10;
FIG. 13 is a perspective view illustrating an embodiment of the sliding
plate device;
FIG. 14 is a perspective view illustrating an embodiment of the camera
stand shown in FIG. 13;
FIG. 15 is a partial sectional view illustrating an embodiment of a
structure of the set spring shown in FIG. 13 and the state when the
sliding plate is attached;
FIGS. 16(a) and 16(b) are partial sectional views illustrating another
states of the sliding plate; and
FIG. 17 illustrates the other embodiment of the sliding plate device.
[DETAILED DESCRIPTION OF EMBODIMENTS]
In the embodiment shown in FIG. 1, for example, a panning portion (A)
rotating horizontally is provided at the bottom of a tripod head, and a
tilting portion (B) which vertically tilts and a sliding plate portion (C)
for securing a device such as a camera, a video camera or a movie camera
are sequentially connected to one another.
In the panning portion (A), a rotating member (3) is rotatably connected
through a bearing, etc. to a panning shaft (2) as a center of a horizontal
rotation which is fixed to a fixed portion (1). This fixed section (1)
does not rotate. A longitudinal shaft (4) provided into the tilting
portion (B) is connected to the rotating member (3). A rotation of the
rotating member (3) is transmitted through the longitudinal shaft (4) to
the tilting portion (B) and the sliding plate portion (C) connected
thereto so as to give a desired panning of the device mounted on the
tripod head.
A panning braking device is provided on the panning shaft (2).
In this panning braking device, two braking units (5) and (6) for acting a
braking force against the rotation of the rotating member (3) are
concentrically arranged through a fixing member (7). The braking units (5)
and (6) are different in the braking force from each other. In this
embodiment, the braking force of the braking unit (5) is smaller than that
of the braking unit (6). These braking units (5) and (6) may possibly
comprise a braking plate, an intermediate member and a viscous fluid, for
example, as disclosed in the above-mentioned Japanese Utility Model
Provisional Publication No. 2-114,297 and the U.S. Pat. No. 4,979,709. As
shown in FIG. 2, two rows of recesses (12) and (13) selectively engaging
with one of the check pins (10) and (11) are concentrically arranged on
the sides of cases (8) and (9) of the braking units (5) and (6) to permit
a free switchover of torque as described later. By inserting or removing
the check pins (10) and (11) into or from any of the recesses of the
recesses tows (12) and (13), torque is switched over to gradually generate
and act a braking force against the panning. Insertion or removal of the
check pins (10) and (11) for this torque switchover are carried out
through a check pin driving shaft (14) supported by the longitudinal shaft
(4) shown in FIG. 1.
As shown in FIGS. 3 and 4, the check pins (10) and (11) are arranged
through the check pin driving shaft (14) above the recess of the recesses
rows (12) and (13) of the braking units (5) and (6). As shown in FIG. 4,
grooves (15) and (16) are respectively provided in the check pins (10) and
(11) to movably engage with driving portions (17) and (18) of the check
pin driving shaft (14). The driving portions (17) and (18) of the check
pin driving shaft (14) are for vertical movements of the check pins (10)
and (11), and are different in shape from each other to achieve vertical
movements in cycles inherent to the check pins (10) and (11). These
vertical movements of the check pins (10) and (11) are available from the
rotation of the check pin driving shaft (14). As shown in FIGS. 2 and 3,
coil springs (19) and (20) are fitted to the top portions of the check
pins (10) and (11) to produce an elastic force between the longitudinal
shaft (4) and the check pins (10) and (11), intensify the vertical
movements of the check pins (10) and (11), and ensure insertion into or
removal from the recesses rows (12) and (13) provided on the braking units
(5) and (6). An operating button (21) is also provided at the tip portion
of the check pin driving shaft (14). The check pin driving shaft (14) can
be rotated by turning the operating button (21) and vertical movements of
the check pins (10) and (11) by the rotation of the check pin driving
shaft (14) allow to switch over torque of a desired braking force.
In the embodiment shown in FIG. 5, for example, the driving portion (17)
has an approximately rectangular cross-sectional shape so as to permit an
alternative switchover between insertion and removal of the check pins
(10) into and from the recesses of the recesses row (12) provided on the
braking unit (5). The other driving portion (18) has, on the other hand,
an almost 1/4 circular cross-sectional shape so as to permit a
continuation of the former state where the check pin driving shaft (11) is
not inserted into the recess of the recesses row (13) provided on the
braking unit (6) and a continuation of the latter state where the check
pin (11) is inserted. The continuations of the former and latter states
take place in turn.
FIG. 5 depicts the status 0 of the check pin driving shaft (14) in which
the check pins (10) and (11) are lifted up by the driving portions (17)
and (18) and do not engage with any recess of the recesses rows (12) and
(13) of the braking units (5) and (6). In this status 0, no braking force
acts upon the panning.
When the check pin driving shaft (14) is turned by 90.degree. in the arrow
direction in FIG. 5 to achieve the status 1, the driving portion (17)
rotates by 90.degree., and the check pin (10) goes down under the effect
of the elastic force of the coil spring (19) and is inserted into and
engaged with one of the recesses of the recesses row (12). When the
driving portion (18) is rotated by 90.degree., on the other hand, the
check pin (11) maintains the lifted state because of the special shape of
the driving portion (18), so that the check pin (11) is not inserted into
a recess of the recesses row (18). In other words, in the status 1, only
the braking force of the braking unit (5) acts during the panning.
When panned, the longitudinal shaft (4) rotates together with the rotating
member (3) shown in FIG. 1. Since the check pin (10) is engaged with a
recess of the braking unit (5) by the check pin driving shaft (14)
supported by the longitudinal shaft (4), the case (8) of the braking unit
(5) rotates corresponding to the panning of the longitudinal shaft (4).
The braking plate and other components incorporated in the braking unit
(5) are, on the other hand, fixed through the fixing member (7) to the
panning shaft (2). A resistance is therefore generated by the viscous
fluid in the braking unit (5). This resistance serves as a braking force
and acts against the panning.
Turning the check pin driving shaft (14) by further 90.degree. into the
status 2 renders the driving portion (17) in the same status as the status
0, thus lifting up the check pin (10) and removing it from the recess. The
check pin (11) goes down under the effect of the elastic force of the coil
spring (20) by the rotation of the driving portion (18) and is inserted
into and engaged with a recess of the recesses row (13). In the status 2,
only the braking force of the braking unit (6) acts against the panning.
Because the braking force of the braking unit (6) is larger than that of
the braking unit (5), a larger braking force acts in the status 2 than in
the status 1.
Turning the check pin driving shaft (14) by further 90.degree. into the
status 3 causes both the check pins (10) and (11) to be inserted into and
engaged with recesses of the recesses rows (12) and (13) of the braking
units (5) and (6). The braking force is summed up those of the braking
units (5) and (6).
In the present invention, four degrees of the braking force as mentioned
above may be available, and it is possible to gradually switch over
between these degrees of the braking force. Panning in response to the
weight of the device such as a camera is thus achieved, and a smooth
panning is also available. By appropriately adjusting the number of the
braking units and the shape of the driving portion of the check pin
driving shaft, it is possible to act a braking force against the panning
which has any magnitude and can be switched over at any of degrees. The
display of the degree of the braking force such as 0 to 3 may be provided
at a convenient place such as at the operating button (21) shown in FIG.
3, and a user can switch over at torque of the desired braking force
simply and easily while confirming the display.
In the tilting section (B) of the tripod head shown in FIG. 1, a tilting
strut (23) is rotatably supported by a bearing, etc. to an unrotatable
tilting shaft (22) which is fixed to the longitudinal shaft (4). In this
embodiment, a weight balancer for ensuring a smooth tilting is provided at
the right of the tilting shaft (22).
In this weight balancer, two spring units (26) and (27) having spiral
springs (24) and (25) therein are concentrically fitted through a fixing
member (28) on the tilting shaft (22). These spring units (26) and (27)
generate righting moments to act against the tilting of the tilting struct
(23). The righting moments of the spring units (26) and (27), i.e., the
elastic forces of the spiral springs (24) and (25) are different from each
other. In this embodiment, the righting moment of the spring unit (26) is
smaller than that of the spring unit (27).
FIGS. 6 and 7 illustrate the spiral springs (24) and (25) in the spring
units (26) and (27), respectively.
It is possible to impart different elastic forces to the springs
incorporated in the spring units by selecting an appropriate thickness,
material, diameter or other parameters. For each of these spiral springs
(24) and (25), one ends (29) and (30) are fixed in a groove (31) of the
tilting shaft (22) shown in FIG. 1, and the other ends (32) and (33) are
fixed to the fixing portions (36) and (37) of the cases (34) and (35) of
the spring units (26) and (27) as shown in FIGS. 8 and 9, respectively.
Elastic forces are produced between the tilting shaft (22) and the cases
(34) and (35) and righting moments act to restore to the original state of
the tilting strut (23) while tilting. In FIG. 1, two spiral springs (24)
and (25) are incorporated in the spring units (26) and (27), respectively,
but there is no limitation in the number of the spiral spring. An
appropriate number may be selected in response to the weight of the device
such as a camera. As shown in FIGS. 6 and 7, the spiral direction of the
spiral springs (24) and (25) in the spring units (26) and (27) may be, for
example, reversed between the two.
As shown in FIGS. 8 and 9, each recess (38) and (39) is provided on the
side of each case (34) and (35) of the spring units (26) and (27). When
the spring units (26) and (27) are assembled, those recesses (38) and (39)
become in parallel with each other.
As shown in FIGS. 10(a) and 10(b), check pins (42) and (43) are located at
the positions corresponding to the recesses (38) and (39) of the cases
(34) and (35). These check pins (42) and (43) are inserted into a casing
(45) provided on the side of a cover (44) of the tilting portion (B) shown
in FIGS. 1 and As shown in FIG. 10, the check pins (42) and (43) possess
auxiliary pins (46) and (47). These auxiliary pins (46) and (47) run
through long holes (48) and (49) of the casing (45) and project outward
from the casing (45). It is therefore possible to cause the check pins
(42) and (43) to slide within the range of the length of the long holes
(48) and (49) of the casing (45). Coil springs (50) and (51) are fitted at
the upper portions of the check pins (42) and (43), and ensuring insertion
into and removal from the recesses (38) and (39) provided on the cases
(34) and (35). A check pin driving cap (52) for sliding the auxiliary pins
(46) and (47) is rotatably provided on the casing (45) with the side end
surface thereof in contact with the auxiliary pins (46) and (47).
Driving portions (53) and (54) for sliding the check pins (42) and (43) are
provided on the side end surface of the check pin driving cap (52), and
are different in shape from each other so as to achieve slide in cycle
inherent to the individual check pins (42) and (43).
As shown in FIG. 12, check pin driving portions (53) (54) are provided on
the side end surface of the check pin driving cap (52). The check pin
driving portion (53) causes the check pin (42) shown in FIG. 10 to be, in
turn, inserted into or removed from the recess (38) on the side surface of
the case (34) of the spring unit (26). On the other hand, the check pin
driving portion (54) makes one state continue twice and change into the
other state after the continuation of that state by changing insertion and
removal of the check pin (43) into and from the recess (39) of the case
(35) of the spring unit (27). In this embodiment, the driving portions
(53) and (54) have a phase of 180.degree.since the two check pins (42) and
(43) are in parallel with each other.
In the status 0, the auxiliary pins (46) and (47) do not slide, and hence
the check pins (42) and (43) are not inserted into the recesses (38) and
(39) provided on the cases (34) and (35) of the spring units (26) and
(27). In other words, righting moments do not act against the tilting in
the status 0.
When the status 1 is achieved by turning the check pin driving cap (52) in
the arrow direction in FIG. 10(a) by 45.degree., the auxiliary pin (46) is
pushed by the driving portion (53) and slides. As a result, the check pin
(42) slides and is inserted into and engaged with the recess (38). On the
other hand, the auxiliary pin (47) maintains the same status as the status
0 because of the shape of the driving section (54). The check pin (43) do
not therefore engage with the recess (39). In other words, only the spring
unit (26) actuates and a righting moment thereof acts against the tilting.
When tilting, the cover (44) connected to the tilting strut (23) shown in
FIG. 1 tilts together with the tilting strut (23). Since the check pin
(42) is incorporated in the casing (45) of the cover (44) and engages with
the recess (38) of the case (34). The case (34), the case (34) of the
spring unit (26) therefore rotates around the tilting shaft (22).
Corresponding to this tilting of the case (34), an elastic force is
produced in the spiral spring (24) incorporated in the spring unit (26),
thus producing a righting moment.
When turning the check pin driving cap (52) by further 45.degree. from the
status 1 to the status 2, the driving portion brings the auxiliary pin
(46) back to the position corresponding to the status 0. The check pin
(42) is removed from the recess (38). The auxiliary pin (47) is, on the
other hand, pushed by the driving portion (54) and slides, this causing
the check pin (43) to slide and be inserted into and engaged with the
recess (39) provided on the case (35). In the status 2, only the spring
unit (27) actuates. Because the righting moment of the spring unit (27) is
larger than that of the spring unit (26), the righting moment in the
status 2 is larger than that in the status 1.
When turning the check pin driving cap (52) by further 45.degree. from the
status 2 to the status 3, both the check pins (42) and (43) engage with
the recesses (38) and (39), so that the sum of the righting moments of the
spring units (26) and (27) acts against the tilting.
In the present invention, as described above, it is possible to simply and
easily switch over the righting moment of the weight balancer, and this
switchover is achieved by means of simple structure and configuration. The
operability upon tilting of the tripod head is also improved.
The check pin driving cap (52) may be rotated through the operating button
(55) connected to the check pin driving cap (52) as shown in FIG. 10. The
display of the above-mentioned status 0 to 3 may be provided on this
operating button (55), and hence a user can simply and easily confirm the
magnitude of the righting moment. It is needless to mention that the shape
of the side end surface of the check pin driving cap (52) is not
restrictive in the embodiment mentioned above, but any appropriate one may
be selected in response to the number of the spring unit, switchover stage
of the righting moment or other parameters.
A tilting braking device for generating a braking force to act against the
tilting of the tilting strut (23) is provided at the left of the tilting
shaft (22) in the tilting portion (B) of the tripod head shown in FIG. 1.
This tilting braking device uses the braking units of the same
configuration and structure as of the panning braking device provided in
the panning portion (A) as described above.
More specifically, braking units (60) and (61) having circular rows of
recesses (58) and (59) on the sides of the cases (56) and (57) are
concentrically supported through a fixed member (62) on the tilting shaft
(22). A torque switchover mechanism (not shown) is applied to for the
braking units (60) and (61), which has the same configuration and
structure as of the above-mentioned righting moment switchover mechanism
for the weight balancer. This torque switchover mechanism makes it
possible to switch over the braking force against the tilting on the side
of the cover (63). This tilting braking device makes it available a smooth
tilting with an improved operability.
Further, a sliding plate device, for example, as shown in FIG. 13 is
connected to the upper portion of the tilting strut (23) in the sliding
portion (C) of the tripod head shown in FIG. 1.
The sliding plate device disclosed in Japanese Utility Model Provisional
Publication No. 2-96,099 and the U.S. Pat. No. 4,959,671 is preferably
prerequisite to the present invention. More particularly, as shown in FIG.
13, a sliding plate (65) having a camera fitting screw (64) for securing a
device such as a camera is provided slidably in the arrow direction in
FIG. 13 and releasably on the camera stand (66). As shown in FIG. 14, a
vertically movable stop pin (67) and a stopper (68) are provided on the
upper surface of the camera stand (66). These stop pin (67) and stopper
(68) movably engage with grooves provided on the back surface of the
sliding plate (65) shown in FIG. 13. The vertical movement of the stop pin
(67) is accomplished by the push-button (69) on the end edge of the camera
stand (66). A locking lever (70) for fixing the sliding plate (65) at any
position is provided on the side end portion of the camera stand (66). In
the present invention, a set spring (71) capable of floating and sinking
along the inner side surface of the camera stand (66) is provided for not
only fitting of the sliding plate (65) in the sliding direction, but also
fitting from above the camera stand (66).
As shown in FIGS. 15 and 16, the side surface of the set spring (71) is,
for example, slant so as to meet the inner side surface of the camera
stand (66) and the side surface of the sliding plate (65). A spring (72)
is incorporated in the set spring (71). An end of this spring (72) is
fixed on the tilting strut (23). The elastic force of the spring (72)
permits floating and sinking of the set spring (71) in the arrow direction
in FIGS. 15 and 16.
When fitting the sliding plate (65) onto the camera stand (66) as shown in
FIG. 15, one of the side ends of the sliding plate (65) opposite to the
set spring (71) is brought into contact with the inner side surface of the
camera stand (66) and then the set spring (71) is pressed by the rear of
the sliding plate (65) and is sunk down along the inner side surface of
the camera stand (66).
As shown in FIG. 16(a), when the set spring (71) is completely sunk down,
the set spring (71) comes off the lower surface of the sliding plate (65),
so that the sliding plate (65) is positioned at a prescribed position on
the camera stand (66).
Then, as shown in FIG. 16(b), the elastic force of the built-in spring (72)
causes the set spring (71) to restore the original state, press and
support the other side end of the sliding plate (65) than that mentioned
above.
As shown in FIG. 17, it is possible to provide each set spring (71a) (71b)
at each inner side portion of the camera stand (66) in the present
invention. There is no particular limitation in the installation of the
set spring to the inner side portion of the camera stand.
It is accomplished to simply and easily fit the sliding plate (65) mounted
a device such as a camera, a video camera, a movie camera or the like from
a side direction of the camera stand (66) independent of the size of that
device and to improve a operability.
It is needless to mention that the present invention is not limited to the
embodiments described above, but many variations are possible in details.
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