Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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BALANCED CAMERA SLIDER
BACKGROUND OF THE INVENTION
[0001] The field of the invention is camera cranes and camera sliders.
Camera
cranes are often used in motion picture and television production. The motion
picture or
television camera is typically mounted on the front end of a crane arm with
counterweights at the back end of the crane arm. The crane arm is pivotally
supported
on a base to allow the crane arm to tilt up and down about a tilt axis and
from side-to-
side about a pan axis. The base is typically supported on a camera dolly,
wheeled
mobile base, or truck.
[0002] Telescoping camera cranes have a telescoping arm that can
extend and
retract, providing far more capability than fixed length crane arms. However,
existing
telescoping camera cranes generally weigh several hundred kilograms, which
exceeds
the safe load carrying capacity of small portable camera dollies.
Consequently, for
filming in confined or less accessible spaces where only a small portable
camera dolly
can be used, there are few if any options for using a telescoping camera
crane.
[0003] Of course, existing telescoping camera cranes can be made
smaller which
also makes them lighter. However, regardless of the size, the camera crane
must be
able to consistently hold the camera (and various associated payloads such as
a
remote camera head) in a steady position, even with the arm fully extended. As
the
camera crane size is reduced, the smaller structural components of the camera
crane
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have reduced capability to resist unintended or undesirable camera movements,
due to
bending, flexing, twisting, or vibration. Accordingly, engineering challenges
remain in
designing a lightweight and compact telescoping camera crane.
[0004]
Camera sliders have a camera mounting platform slidably attached onto a
track or rail, for moving the camera linearly. Camera sliders are useful for
recording or
filming various types of sequences. For example, a camera slider may be for a
single
axis sequence, where the camera is simply moved linearly with the lens
perpendicular
to the track, or in a so-called push-in sequence, with the lens parallel to
the track, for
pushing into the scene. Using a camera head on the slide allows for panning or
tilting
during sliding movement. The track may optionally be inclined, adding
further
versatility.
[0005]
However, most sliders have a limited payload capacity primarily because
they lack any form of counterbalancing system. They can also be time consuming
to
set up and use. Consequently engineering challenges remain in the design of
camera
sliders.
SUMMARY OF THE INVENTION
[0006]
In one aspect a camera slider has a base and a tubular hollow outer arm
pivotally attached to the base. A counterweight carriage is supported on the
outer arm
on carriage rollers. An electric drive motor moves the counterweight carriage
linearly on
top of the outer arm. A slider counterweight is movable from a first position,
wherein the
counterweight carriage is at or near a first end of a first end of outer arm
and the slider
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counterweight is at or near a second end of the outer arm, optionally
projecting out of
the arm, and a second position wherein the counterweight carriage is at or
near the
second end of the arm and the slider counterweight is at or near the first end
of the arm.
[0007] Other aspects and features are shown in the drawings, which
show one
example of how the lightweight camera crane and a camera slider may be
designed,
and which are not intended to specify a limit on the scope of the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0008] Fig. 1 is a top, rear and right side perspective view of a
lightweight
telescoping camera crane.
[0009] Fig. 2 is an exploded perspective view of the camera crane
as it is shown in
Fig. 1.
[0010] Fig. 3 is a similar exploded perspective view of major
elements of the
camera crane shown in Figs. 1 and 2, with components removed for purpose of
illustration.
[0011] Fig. 4 is a side view of the camera crane of Figs. 1 and 2
with the base and
trim weight platform removed.
[0012] Fig. 5A is a rear view of the camera crane of Fig. 4.
[0013] Fig. 5B is a view similar to Fig. 5A but with the nose
assembly removed, for
purpose of illustration.
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[0014] Fig. 6 is a section view taken along line 6-6 of Fig. 4, with
the counterweight
carriage removed.
[0015] Fig. 7 is a top view of the crane of Figs. 1-2, showing the
crane with the
inner arm in a partially extended position.
[0016] Fig. 8 is a side view in part section of the crane as shown in Fig.
7.
[0017] Fig. 9 is an enlarged detail section view of the back end of
the crane as
shown in Fig. 8.
[0018] Fig. 10 is an enlarged detail section view of a portion of the
counterweight
carriage as shown in Fig. 8, with covers removed in Figs. 7-10 for purpose of
illustration.
[0019] Fig. 11 is a top, right and rear perspective view, in part section,
of the outer
arm shown in Figs. 1 and 2.
[0020] Fig. 12 is an exploded top, rear and right side perspective
view of the inner
arm shown in Figs. 1 and 2.
[0021] Fig. 13 is a top, rear and right side exploded perspective view
of the base
shown in Figs. 1 and 2.
[0022] Fig. 14 is a top and front exploded perspective view of the
base frame
shown in Fig. 13.
[0023] Fig. 15 is a front, top and right side perspective view of the
motor housing
shown in Figs. 2 and 9.
[0024] Fig. 16 is a section view of the motor housing shown in Fig. 15.
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[0025] Fig. 17 is an enlarged section view detail of the sprocket and
pulleys shown
in Fig. 16.
[0026] Fig. 18 is a perspective view of a camera slider, with the
outer arm cut away
for purpose of illustration.
[0027] Fig. 19 is a partially exploded perspective view of the camera
slider shown
in Fig. 18.
[0028] Fig. 20 is a side view of the camera slider shown in Fig. 19.
[0029] Fig. 21 is an enlarged detail view of the leveling head shown
in Figs. 18-20.
[0030] Fig. 22 is a rear perspective view of the slider counterweight
shown in Figs.
18-20.
[0031] Fig. 23 is a perspective view illustrating installation of the
slider
counterweight shown in Fig. 22 onto the telescoping camera crane shown in
Figs. 1-17
[0032] Fig. 24 is a perspective section view taken along line 24-24 of
Fig. 23.
[0033] Fig. 25 is a perspective view of the telescoping locking strut
shown in Figs.
18-20.
[0034] Fig. 26. is a section view of the telescoping locking strut
shown in Fig. 25.
[0035] Fig. 27 is a perspective view of the camera slider of Figs. 18-
20 in use.
[0036] Fig. 28 is a side view of an alternative camera slider
embodiment shown in
the full down position.
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[0037] Fig. 29 is a side view of the camera slider embodiment of
Fig. 28 shown in
the full up position.
[0038] Fig. 30 is an exploded perspective view of the telescoping
locking strut
shown in Figs. 28-29.
[0039] Fig. 31 is a section view of the telescoping locking strut shown in
Fig. 30.
[0040] Fig. 32 is a perspective view of the electronic levelling
head shown in Figs.
28 and 29.
[0041] Fig. 33 is an exploded perspective view of the electronic
levelling head
shown in Fig. 32.
[0042] Fig. 34 is a side view of an alternative embodiment of a manual
levelling
head.
[0043] Fig. 35 is a top, front and left side perspective view of
the manual levelling
head shown in Fig. 34.
[0044] Fig. 36 is a top, front and right side perspective view of
the manual levelling
head shown in Fig. 34.
DETAILED DESCRIPTION OF THE DRAWINGS
[0045] As shown in Figs. 1 and 2, a camera crane 20 has a crane
arm 22 including
an outer arm 56 and an inner arm 58 telescopically extendible into and out of
the outer
arm 56. The outer arm 56 is pivotally mounted on a base 24 via left and right
axles 26.
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Handles are attached to the outer arm 56, such as a rear handle 40 and side
handles
44, to allow the crane arm 22 to be easily grasped, moved, or held into a
desired
position. A nose frame 50 is rigidly attached, e.g., bolted, onto the front
end of the inner
arm. The camera 25 (shown in Fig. 18) is attached to the mounting plate 52.
The nose
frame 50 may be magnesium, to reduce weight. Referring now also to Figs. 3 and
4,
one or more tilt motors 112 acting through a tilt gear drive or linkage 114
pivot the
mounting plate 52 as required to keep the mounting plate (and the camera 172
on the
mounting plate) level, regardless of the tilt angle of the crane arm 22.
[0046] A counterweight carriage 34 rolls on a top surface of the outer
arm 56 to
keep the crane arm 22 balanced as the inner arm 58 extends and retracts.
Specifically,
as shown in Figs. 2 and 13, the counterweight carriage 34 has top carriage
rollers 46
which roll on a top surface of the outer arm 56, and side carriage rollers 48
which roll on
the sides of the outer arm 56. Rails or tracks may optionally be provided on
the outer
arm to provide rolling surfaces. The counterweight carriage 34 typically
carries a fixed
number of counterweight plates selected so that the crane arm is balanced
regardless
of the position of the inner arm, with a minimum payload or no payload on the
mounting
plate 52. The weights on the counterweight carriage may be changed as needed
if the
nose frame 50 is replaced with a heavier or lighter nose assembly.
[0047] As shown in Figs. 1 and 2, a trim weight tray 36 is attached to
the back end
of the outer arm 56. Trim weight plates may be added to or removed from the
trim
weight tray to balance the crane arm 22 after the payload is attached to the
nose frame
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50 and the crane 20 is ready for use. Sliding or rolling trim weights may be
provided on
the side handles for making small balance adjustments.
[0048] Referring now to Figs. 7-10, an drive motor 102 drives a
sprocket 104
through a gear drive 96 within a motor housing 94 at the back end of the outer
arm 56.
The gear drive 96 may have a drive ratio of 2-6, so that it is back-drivable
with a force of
about 90 to 225 Newtons applied to the arm, to allow the counterweight
carriage to be
moved manually. Alternatively, a clutch may be provided in the gear drive to
manually
disengage the motor from the inner arm, to allow movement of the inner arm by
hand
without back driving the motor. A first end of a chain 106 is attached to the
back end of
the counterweight carriage 34 via a first chain anchor 80. The chain 106 wraps
around
the sprocket 104 with the other end of the chain 106 attached to the back end
of the
inner arm 58 via a second chain anchor 80, as shown in Fig 10.
[0049] As shown in Figs. 7, 9 and 17, in the example shown, two rear
cables 115
run alongside of the chain 106, with one end of each cable attached to the
back end of
the counterweight carriage 34 via a cable anchor 78, and with the other end of
each
cable attached to near the back end of the inner arm. The chain and cable
anchors
allow tension to be adjusted.
[0050] A first end of each of a group of three front cables 110 is
attached to a front
end of the counterweight carriage 34 via a first cable anchor 78, with the
cables running
over pulleys 82 on the front end of the outer arm 56, and with second end of
each front
cable 110 attached to the inner arm 58 via a second cable anchor 78 adjacent
to, and in
front of, the first chain anchor 80. The chain 106 may be replaced by a belt
and the
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front cables 110 may be replaced by a chain or belt, and varying numbers of
cables
may be used, depending on the specific design of the crane 20. The drive motor
102
may be powered via an electrical cable connected to batteries or other power
supply
typically carried on the camera dolly. The drive motor 102 may be controlled
via a
wireless controller 170 carried by the crane operator, or via a hand control
174 attached
or tethered to the crane arm 22.
[0051] As shown in Figs. 11 and 12, upper roller tracks 70 and
lower roller tracks
71 are attached to the sides of the inner arm 58. Left front rollers 86 and
right front
rollers 87 are rotatably attached to left and right front plates 84 and 85,
respectively,
bolted onto the front end of the outer arm 56. The left and right front
rollers 86 and 87 fit
between the upper roller tracks 70 and the lower roller tracks 71. Upper inner
rear
rollers 72 and lower inner rear rollers 74 are rotatably attached to roller
brackets 76 on
opposite sides of the back end of the inner arm 58. The rollers may be TorIon
polyamide-imide polymer, providing quiet and wear resistant operation. A
second pair
of left and right front rollers 86 may optionally be provided at the front end
of the outer
arm 56, providing a total of four front rollers 86.
[0052] With the inner arm retracted, the weight of the inner arm,
and the weight of
the nose assembly and the camera, is supported on the lower roller tracks 71.
As the
inner arm 58 extends, the load on the inner arm 58 is shifted onto the upper
roller tracks
70 supported by the front rollers 86, with the upper inner rear rollers 72 at
the back end
of the inner arm rolling on the inside top surface of the outer arm 56. Cable
supports 60
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are captive around and roll on the upper roller tracks 70 to provide
intermediate cable
support locations for cables running to the camera on the mounting plate 52.
[0053] Referring still to Figs. 6, 11 and 12, the outer arm 56 may be
a hollow
aluminum extrusion or tube formed as a rectangle with a top channel 90 in the
top wall
between left and right top flanges 88 and an internal channel 92 under the top
channel
90. As shown in Fig. 5, the top carriage rollers 46 roll on the left and right
shoulders
108 of the outer arm 56, between the left and right top flanges 88, with the
side carriage
rollers 48 rolling on the sides of the flanges 88. As shown in Fig. 5B, the
flanges 88
have an angle section 89. The side carriage rollers 48 may have a flange 49
which fits
under the angle section 89 to prevent the counterweight carriage 34 from
lifting up off of
the top surface of the outer arm 56. Referring to Figs. 8-10, the chain 106
and the front
cables 110 and rear cables 115 are positioned within the internal channel 92,
providing
a more compact design.
[0054] Turning to Figs. 1, 2 and 13, a threaded fitting 38, such as a
MitchelTM
mount fitting, is provided at the bottom of the base 24 for attaching the base
24 onto a
supporting structure, such as a column of a camera vehicle or onto the arm of
a camera
dolly. As shown in Fig. 14, a base frame 30 is rotatably supported on a center
post 160
via pan bearings 162, with the pan bearings 162 held in place via a frame cap
164
bolted onto the upper end of the center post 160.
[0055] In Fig. 13, the left and right base plates 28 and 32 are bolted onto
the sides
of the base frame 30. The axles 26 on the outer arm 56 extend into bearings at
the
upper ends of the base plates, so that the crane arm 22 is pivotally attached
to the base
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24 and can tilt up and down. An encoder chain 142 extends around a crane arm
sprocket 144 fixed to the right side of the outer arm 56 around the axle 26,
and around
an encoder sprocket on a rotary encoder 140 on the right base plate 32. The
rotary
encoder 140 senses the tilt angle of the crane arm 22 and provides a tilt
angle signal to
a controller which controls the tilt motors 112 to keep the mounting plate 52
level as the
crane arm 22 tilts up and down.
[0056] A right tilt brake assembly 120 includes a brake sprocket 126
and a lever
sprocket 128 both rotatably mounted on the right base plate 32 and connected
via a
brake chain 124. An idler 132 maintains tension on the brake chain 124. A
brake lever
is rigidly attached to the lever sprocket 128. The brake sprocket 126 is
mounted on a
lead screw thread on a tension shaft 138 on the right base plate 32. A brake
plate 122
is positioned between the brake sprocket 126 and the outside of the right base
plate 32.
A brake ring 145 is positioned between the inside of the base plate and the
outer arm.
The brake ring 145 may be Delrin acetal resin. The brake sprocket 126 and the
lever
sprocket 128 and the brake chain 124 are covered via a chain cover 134.
[0057] Although Fig. 13 largely shows the right side of the tilt brake
assembly 120,
the same components as described above are provided on the right base plate
32.
Specifically, a left tilt brake assembly 120 on the left base plate has an
upper left tilt
brake sprocket 126 co-axial with the left axle, a lower left tilt brake
sprocket spaced
apart from the upper left tilt brake sprocket, a left tilt brake chain
connecting the upper
and lower left tilt brake sprockets, and a left tilt brake lever rigidly
attached to the lower
left tilt brake sprocket, with movement of the left tilt brake lever braking
pivoting
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movement of the outer arm on the base. The right tilt brake assembly 120 may
be a
mirror image of the left tilt brake assembly 120.
[0058] A tilt brake lever axle 136 connects the lever sprockets on
the left and right
sides. Pulling either the left or right brake lever 130 rotates the lever
sprocket 128,
which rotates the brake sprocket 126, causing the brake sprocket 126 to move
inwardly
on the tension shaft, compressing the brake ring 145 between the outer arm and
the top
end of the right base plate 32. This movement exerts braking force on both
sides of the
outer arm 56, without acting on the axle bearings. The tilt brake assembly may
be used
to slow tilt movement of the crane arm 22, or to lock the crane arm at a fixed
tilt angle.
As shown in Fig. 13, the tilt brake assembly 120 has a minimum width to allow
the side
weights on the counterweight carriage 34 to pass over the tilt brake assembly
without
interference.
[0059] In Fig. 13, a monitor support 146 is bolted onto the right
base plate 32 for
supporting a monitor 176 providing an image from the camera to the camera
operator
and/or the crane operator. The monitor consequently pans with the crane arm
22,
allowing the operators to more easily view the image from the camera
continuously.
With the monitor in constant view from the side of the crane arm 22, and with
controls
for the camera and for the drive motor at or near the back of the crane arm
22, or on a
hand held unit, the camera and the crane 20 may be entirely controlled by a
single
operator. A second monitor support may be provided on the left base plate 28.
The
monitor support may extend telescopically outward to allow the monitor to be
positioned
further to one side of the crane, as may be desired.
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[0060] Referring to Figs. 13 and 14, a pan brake assembly 150 has
a split collar
152 around the center post 160, which is rigidly attached to the base frame
30. A pan
brake rod 154 extends through the split collar 152 and is threaded into
followers 158
having left and right hand screw threads. A pan brake lever 156 is attached to
one or
both sides of the pan brake rod 154. Turning the pan brake lever 156 drives
the
followers 158 towards each other, causing the split collar 152 to clamp onto
the center
post 160, braking panning movement of the crane arm 22. The pan brake assembly
150 may be used to slow panning movement of the crane arm 22 about the base 24
or
to lock the crane arm 22 against any panning movement. Top weights 35 and side
weights 37 may be placed on the counterweight carriage 34, with the side
weights 37
having a lower end extending below a bottom surface of the outer arm 56, and
with the
pan brake rod 154 below the lower ends of the side weights 37. As a result,
pan brake
assembly does not interfere with movement of the counterweight carriage 34.
[0061] Turning to Figs. 15, 16 and 17, the sprocket 104 is
attached to the output
shaft 105 of the gear drive 96. The gear drive 96 may have a gear ratio which
is low
enough to allow back driving the drive motor 102. This allows the inner arm to
be
manually extended or retracted, e.g., by pushing or pulling on the
counterweight
carriage by hand, if electrical power is not available. The pulleys 82
alongside of the
sprocket 104 have bearings supported on a pulley housing 116 attached to the
motor
housing 94. Consequently, the radial loading on the output shaft 105 is
reduced
because only the tension of the chain 106, and not the tension of the rear
cables 115, is
applied to the output shaft 105. The load on the internal shafts and bearings
of the
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drive motor 102 and the gear drive 96 are reduced, which reduces wear and
noise. The
tension load on the chain 106 is also reduced as the tension in the rear
cables 115
offsets a majority of the tension in the front cables 110.
[0062] In use, the crane arm 22 is mounted on a camera dolly or
pedestal. In
designs having a two meter telescoping movement, the crane arm 22 is light
enough to
be lifted by a camera crew. The crane arm 22 can therefore be mounted on a
camera
dolly without lifting equipment. The crane arm 22 is typically first locked
into a
horizontal position, either via the tilt brake or via a strut temporarily
attached to the base
frame 30 and to the crane arm 22. A camera is attached to the mounting plate
and the
crane arm 22 is balanced as described above. The crane arm 22 is positioned as
desired via a crane operator grasping the handles and pushing or pulling the
crane arm.
[0063] The inner arm 58 is telescopically extended using a wired or
wireless
control which controls the drive motor 102. When the motor is actuated to
extend, the
drive motor 102 turns the sprocket 104 counterclockwise in Fig. 8. The chain
106 pulls
the counterweight carriage 34 towards the rear of the crane arm 22.
Simultaneously,
the front cables 110 pull the inner arm forward, extending the inner arm. The
drive
motor 102 and gear drive 96 may be selected so that they can be readily back-
driven,
by pushing or pulling on inner arm 58 with a nominal force of e.g., 90 to 225
N. This
allows the inner arm 58 to be manually telescopically moved in or out, without
using the
motor.
[0064] The arm is retracted by operating the drive motor 102 in the
reverse
direction, with the chain 106 pulling the inner arm back into the outer arm,
and with the
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front cables pulling the counterweight carriage towards the front of the crane
arm 22.
One or more shock absorbers may be provided on the counterweight carriage or
at front
and rear stop positions on the outer arm 56, to prevent the counterweight
carriage from
making a hard impact at the front or rear limit of travel. The electronic
controller of the
drive motor 102 may also be linked to sensors which detect the position of the
counterweight carriage, to decelerate the counterweight carriage automatically
as it
approaches the front or rear limit of travel. In the example shown with an
outer arm 56
about length of about 300 cm, the inner arm travel is about 215 cm.
[0065] The example shown in the drawings having 2 meters of
extension travel
weighs about 170 kg. Typical crane weights using the design shown are 120 kg
to 200
kg. The same design principals may of course be used to provide even lighter
designs,
having less extension. Since the crane arm 22 has only a single moving arm,
the
weight and complexity of additional rollers, cables and other components
associated
with having two or more moving arms, is avoided. The crane arm 22 also
provides a
more simple design which may be manufactured with fewer components and steps,
and
which may be provided at lower cost compared to existing designs. As described
above, the inner arm 58 is supported within the outer arm only by the front
rollers 86
and the rear rollers 72 and 74, with no intermediate rollers used.
[0066] As shown in Figs. 18, 19 and 20, the camera crane shown in
Figs. 1-17
may optionally be converted for use as a camera slider. In this design, the
inner arm 58
is split into a rear segment 58A and a front segment 58B, as shown in Figs. 3
and 8.
Referring to Figs. 23 and 24, the front segment 58B has an insert section 254
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dimensioned to slide into the front open of the rear segment 58A. The front
segment
58B is installed into the rear segment 58A by sliding the insert section 254
of the of the
front segment 58B into the rear segment 58A, and then securing them together
with a
segment bolt 222 passing through a hole 215 in the insert section 254 and
threaded into
a nut 225 fixed onto the rear segment 58A.
[0067]
The rollers 72 and 74 remain on the back end of the rear segment 58A,
in
the same way as in the design where the inner arm is not split into front and
rear
segments. Similarly, the cables 110 remain attached onto the rear segment 58A,
in the
same way as they are in the design where the inner arm is not split into front
and rear
segments. As also shown in Fig. 24, a front stop plate with resilient bumpers
may be
attached onto the front end of the outer arm, to provide a forward stop
position for the
counterweight carriage, with a similar rear stop plate attached to the back
end of the
outer arm.
[0068]
To convert the camera crane 20 into a camera slider 200, the front
segment
58B is replaced with a slider counterweight 218 shown in Fig. 22. The slider
counterweight 218 is much shorter than the front segment 58B of inner arm 58,
e.g., 5
to 30% of the length of the inner arm 58. With the counterweight carriage 34
at the full
back position, the slider counterweight 218 may protrude forward of the front
plates 84
by only a short length, typically about 10 to 15 cm.
Alternatively, the slider
counterweight may be designed so that it is contained within the outer arm 56
at all
times.
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[0069] As shown in Fig. 22, the slider counterweight 218 may be
formed of welded
plates 250 with lead weights 252 contained in the insert section 254 of the
slider
counterweight 218. The insert section of the front segment 58B has the same
size and
shape as the insert section 254 of the slider counterweight 218, so that they
may be
interchangeably installed onto or into the rear segment 58A of the inner arm
58. The
insert sections 254 may have an internal reinforcing tube 220 around the
segment bolt
hole 215, to allow the segment bolt 222 to be securely tightened without
deforming the
rear segment 58A or the insert section of the front segment 58B, or the insert
section
254 of the slider counterweight 218. A low friction bottom slide bushing 256
may be
provided on the bottom of slider counterweight 218 to provide a low friction
surface
between the slider counterweight 218 and the outer arm 56, if needed. Fig. 18
is drawn
with the outer arm 56 partially cut away to show the crane 20 converted into a
camera
slider 200, with the front segment 58B of the inner arm removed and replaced
with the
slider counterweight 218.
[0070] As shown in Fig. 21, a camera mounting plate 242 on a manual
leveling
head 240 may be adjusted to level using jacking screws, to position the camera
25 in a
level orientation, where the crane arm 22 is at an inclined orientation, as in
the example
shown. The leveling head 240 may be attached onto the counterweight carriage
34 via
the weight bolts 39 shown in Fig. 8, which are used to hold the top weights 35
in place.
In the camera slider configuration, some or all of the top weights 35 may be
removed
since with the crane 20 set up as a camera slider, bending moments on the arm
are
minimal because the payload, i.e. the leveling head 240, the camera 25, and
any
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accessories on the counterweight carriage, travels only along the length of
the outer
arm 56. Referring to Fig. 19, adjustment weights 226 may be removably attached
onto
the front end of the slider counterweight 218 to balance the crane arm 22,
after the
payload is mounted onto the weight carriage 34, or the leveling head 240, if
used.
[0071] As shown in Figs. 20, 25 and 26, a telescoping locking strut 202 may
be
pivotally attached to the base via a base clevis 204, and also pivotally
attached to the
outer arm 56 via an arm clevis 206, as shown in Fig. 20. The telescoping
locking strut
202 may have an outer tube cap 262 attached to a top end of an outer tube 260,
with a
rod 264 attached to the outer tube cap 262. An inner tube 270 is
telescopically slidable
into and out of the outer tube 260 on a collar 266 around the rod 264, and
with the collar
attached to top end of the inner tube 270. An inner tube cap 272 is attached
to the
bottom end of the inner tube 270. A collet 276 is threaded onto the bottom end
of the
outer tube 260. Tightening the collet 276 presses fingers 274 at the bottom
end of the
outer tube 260 onto the inner tube 270. 0-rings 268 may be provided between
the
collet 276 and the inner tube 270, and between the collar 266 and the outer
tube 260.
The collet 276 may be tightened to increase sliding friction between the inner
and outer
tubes, or even locking the strut 202 against any telescoping movement.
[0072] To convert the crane 20 from a telescoping camera crane as
shown in Figs.
1-18, to a camera slider as shown in Figs. 18-27, the counterweight carriage
34 is
moved to the full back position as shown in Fig. 19. This movement may be
achieved
via controlling the drive motor 102, or it may be done manually be pushing on
the
counterweight carriage 34 by hand, in designs that allow back-driving the
motor. With
CA 2979143 2017-09-12
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' 19
the counterweight carriage 34 at the full back position, the inner arm 58 is
fully
extended, and the segment bolt 222 is aligned with a tool clearance hole 223
in one
sidewall of the outer arm 56. A tool is inserted through the tool clearance
hole 223 into
engagement with the segment bolt 222, and the segment bolt 222 is unscrewed
from
the nut 225 and withdrawn. The front segment 58B of the inner tube is then
pulled out
of the rear segment 58A and removed from the crane 20. The slider
counterweight 218
is installed in place of the front segment 58B using the reverse sequence of
steps.
Since only the single segment bolt 222 is used, converting the crane 20
between the
telescoping crane configuration of Fig. 1-17, and the camera slider
configuration 200 of
Figs. 18-27, is fast and simple to perform.
[0073] Typically a camera head is mounted onto the counterweight
carriage 34 to
provide greater versatility, although in some cases the camera may be attached
directly
onto the counterweight carriage 34, and the camera head omitted.
[0074] In use as a camera slider, control of the drive motor 102,
either via a
wireless handheld controller, or via a tethered controller, or a controller on
the crane 20
itself, moves the weight carriage 34 along the top surface of the outer arm
56. At the
same time, the slider counterweight 218 moves by an equal amount in the
opposite
direction. This provides a balanced slider. As a result, the crane arm 20 may
be
inclined or horizontal, and moving the payload along the top of the outer arm
occurs
without weight transfer.
[0075] With the crane 20 converted to the slider configuration of
Figs. 18-27, it may
be used in a much smaller space in comparison to the crane 20 in the
telescoping crane
CA 2979143 2017-09-12
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- 20
mode as shown in Figs. 1-17, because the fully extended length of the crane
arm 20 is
reduced by removing the front segment 58B of the inner arm 58. A known problem
with
conventional camera sliders is that they transfer weight when they slide a
camera back
and forth along the length of the track, which can create a destabilizing
imbalance. With
the crane 20 in the slider configuration 200, the crane 20 remains balanced,
and it can
be used on small camera dollies without risk of imbalance. With the crane 20
in the
slider configuration 200, the overall weight of the crane can also be reduced
typically by
more than 40 or 50% as the front segment 58B of the inner arm is removed,
along with
the counterweights needed to balance the crane arm 20 when it is in the
telescoping
crane configuration shown in Figs. 1-17.
[0076] By releasing the tilt brake assembly 120, the outer arm 56
can be tilted up
or down to provide a camera slider that can be adjusted to different angles
rather than
just horizontal position. The outer arm 56 can also be locked at any angle via
the 276
collet on the telescoping locking strut 202. In the slider configuration shown
in Figs.18-
27, the crane arm 22 remains balanced regardless of the position of the
counterweight
carriage 34. As the outer arm 56 is mounted on the base 24, it can pan and
tilt, without
having to add accessories or equipment. This provides a time saving feature.
[0077] The telescoping locking strut 202 allows the crane arm 20
to be locked at
any angle, including the conventional horizontal position typically used for
camera
sliders. The collet 276 may be tightened or loosened to set a limit on the
force exerted
on the crane arm 20, to avoid over-stressing components of the arm. The collet
276
may be tightened sufficiently to rigidly lock the crane arm 20 in a fixed
position. This
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allows for slider operation with the crane arm 20 at any angle from about 15
or 20
degrees down to about 25 to 35 degrees up, generally with a total elevation
angle range
of 45 to 55 degrees.
[0078] The telescoping locking strut 202 can be loosened to allow
telescoping
action to occur, and it need to be removed in slider operation. The
telescoping locking
strut 202 may also provide positive tilt angle end stop positions. The
telescoping
locking strut 202 is locked or unlocked by manually rotating the collet 276.
Telescoping
movement of the telescoping locking strut is largely silent due to the o-rings
268
between the moving surfaces. When the collet is tightened the o-rings may be
compressed until there is metal-to-metal contact, at which point there is no
movement,
and therefore no noise.
[0079] As shown in Fig. 27, the camera slider 200 may include an
automatic or
motorized camera head 280. In this case, optionally both the sliding movement
and pan
and tilt movement of the camera, may be controlled either automatically by an
electronic
computer controller, or manually via a joystick or other interface, at the
preference of the
user. The computer controller may operate to control pan axis movement
provided by
the first electric motor, and tilt axis movement provided by the second
electric motor, on
the motorized camera head 280 to keep the camera level while the crane arm 20
tilts, or
to keep the camera fixed on a subject while the crane arm pans. Optionally,
the tilt
motors 112 shown in Fig. 4 for telescoping crane use may be provided as a
module
which can also be used on the motorized camera head 280. In this case no
additional
electronic cabling is needed for the conversion from crane operation to slider
operation.
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[0080] As shown in Figs. 20 and 21, the outer arm 56 may have left
and right side
rails 230 supported on left and right rail plates 232 pivotally supported on
the base 24
via the axle 26. The outer arm 56 may be shifted to the front or back,
relative to the
base 24, by loosening rail plated bolts or brakes, and then sliding the outer
arm 56
relative to the base 24, with the weight of the outer arm carried by side
rails 230. This
provides alternative mounting positions 228 of the outer arm 56 on the base
24.
[0081] A method for filming or recording moving images using the
camera slider
200 as described above includes removing a front segment of an inner arm from
a rear
segment of the inner arm of the telescoping camera crane 20, by withdrawing
the insert
section of the front segment of the inner arm from the rear segment of the
inner arm.
The front segment of the inner arm is then replaced with the slider
counterweight by
inserting an insert section of the slider counterweight into or onto the rear
segment of
the inner arm. For this purpose the insert section of the slider counterweight
may have
the same shape and dimensions as the insert section of the front segment of
the inner
arm. The slider counterweight typically has a length 5 to 30% of the length of
the front
segment of the inner arm. In most cases a camera head is mounted onto the
counterweight carriage 34 which is supported on the outer arm on carriage
rollers. The
drive motor is operated to move the counterweight carriage linearly along the
top of the
outer arm in a first direction, which simultaneously moves the counterweight
carriage in
a second direction, opposite to the first direction, so that the camera slider
200 remains
balanced.
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[0082] Turning now to Figs. 28-31, an alternative balanced camera
slider 300 is
supported on a mobile base 304. A telescoping locking strut 302 is pivotally
attached to
the column of the mobile base 304 and to the back end of the camera slider
300. Figs.
29-29 show an electronic levelling head 400 mounted on the camera slider 300.
As
shown in Figs. 28 and 29, the camera slider 300 can pivot between elevation
angles AE
of greater than +/- 45 and up to +/- 500 or 60 , providing a wide range of
elevation
angles, relative to horizontal HH or the ground surface. As shown in Figs. 28
and 29,
resilient down stops 308 and 310 on the camera slider 300 come to rest against
the
column of the mobile base to set the minimum and maximum elevation angles.
[0083] The telescoping locking strut 302 shown in Figs. 30-31 is generally
similar
to the telescoping locking strut shown in Figs. 25-26, but with an extended
range of
travel. The telescoping locking strut 302 has an outer tube cap 362 attached
to the
back end of an outer tube 360. A rod 364 is rigidly attached to the outer tube
cap 362
and extends forward within the outer tube 360. A rod stop 384 is provided on
the
forward end of the rod 364. A collar 366 is attached to the back end of an
inner tube
370, with the collar 366 sliding on the rod 364. A collet 376 is threaded onto
the front
end of the outer tube 360. The collet 376 has an angled or stepped inner
surface which
engages fingers 374. As a result, tightening the collet 376 onto the outer
tube 360
causes the fingers 374 to clamp onto the inner tube 370, locking the strut 302
against
telescoping movement. Conversely, loosening the collet 376 allows telescoping
movement of strut 302, with the inner tube 370 sliding into or out of the
outer tube 360.
In the design shown, the collet 376 is adapted to be tightened and loosened by
turning
CA 2979143 2017-09-12
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with one or two hands, without use of a tool. For some uses, the telescoping
locking
strut 202 or 302 may be removed entirely.
[0084] As the collet may be operated by hand, no tool is needed to
operate the
locking strut 302 to change the elevation angle AE of the camera slider 300.
Extending
movement is limited via the collar 366 running up against the rod stop 384. 0-
rings 368
may be provided on the collar 366 and on the collet 376. The locking strut 302
may be
dimensioned so that the maximum locking force is below a threshold value, even
with
the collet 376 fully tightened onto the threads 380. If used, this feature
allows the
camera slider 300 to be displaced if a force greater than the threshold value
acts on the
camera slider 300, for example if the camera slider 300 accidently collides
with another
object. Allowing displacement of the camera slider 300 under these conditions
may
reduce potential damage to the camera slider 300 and surrounding objects.
[0085] Figs. 32-33 show the electronic levelling head 400 shown in
Figs. 28-29.
As shown in Figs. 32-33, the electronic levelling head 400 has connectors 404
on a
base 402. A motor plate 406 is supported on plate posts 408 and is attached to
the
base 402. A first motor 410 and a second motor 412 is attached to the motor
plate 406.
Each motor has a pinion gear 414 meshed with a ring gear 416. A camera
mounting
plate 422 is rigidly attached to the top end of the ring gear 416, with the
ring gear 416
pivotally attached to arms 418 bolted onto the motor plate 406. A bubble level
may be
provided on the mounting plate 422 and on the ring gear 416. A belt 426
extends
around a sensor sprocket 424 that pivots with the mounting plate 422, and
around an
angle sensor 428 which electronically measures the angle of the mounting plate
422.
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The ring gear 416 has an angular range of movement sufficient to maintain the
camera
mounting plate 422 at a level position (parallel to HH) regardless of the
elevation angle
AE of the camera slider. For example, if the camera slider 300 has an
elevation angle
AE range of +1- 50 , the angular range of movement of the ring gear 416 is at
least
nominally larger, for example +1- 55 or 60 .
[0086] In use, the electronic levelling head is electrically connected
to a controller
430 which senses the angle of the mounting plate 422 relative to horizontal,
and which
also controls the motors 410 and 412. The motors 410 and 412 may be biased in
opposite directions to avoid backlash. The controller 430 may be designed to
automatically keep the mounting plate 422 (and a camera on the mounting plate)
in a
level or horizontal position, regardless of movements of the camera slider 300
or the
mobile base 304. The controller 430 may also control sliding movement of the
levelling
head along the length of the arm, either via preprogrammed movement or based
on an
interface, such as joystick, operated by a camera crew member. The controller
430
may also control operation of the mobile base, if used, such as operation of a
telescoping column, or control of the wheel motors which propel and steer the
mobile
base.
[0087] The camera slider and the levelling head 400 or 450 may
position the
camera lens at an extreme elevation angle, to the extent that parts of the
camera slider
may be in the field of view. In this case, the side handle bars 312 on one or
both sides
of the camera slider can be removed quickly by loosening front and rear
attachment
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bolts 314, to remove the handle bars 312 from the field of view. The side
handle bars
312 may be similar to the handle bar 44 shown in Figs. 1 and 2,
[0088] Figs. 34-36 show an alternative manual levelling head 450 which
may be
used with the camera sliders described above. The levelling head 450 has an
arm plate
462 attached to a base 452 by posts 464. A mounting plate 460 has a standard
fitting
for mounting a camera. The mounting plate 460 is pivotally attached to arms
454 which
are bolted onto the arm plate 462. A locking bolt 458 extends through an arc
slot 456 in
one or both of the arms 454. Temporarily loosening the locking bolt (s) 458
allows for
manually pivoting the mounting plate 460 to a desired position. As best shown
in Fig.
35, a tool 466 for loosening and tightening the locking bolt (s) 458 may be
stored in a
tool bore 468 extending through the arm plate 462. The tool 466 may be secured
in the
tool bore 468 via a magnet 470 on the arm 454, when the tool is not in use.
The
levelling head 450 may optionally have two tools 466, as shown in Fig. 36. In
comparison to the electronic levelling head 400 shown in Fig. 32, the manual
levelling
head 450 is lighter, more compact, and is typically 4-6 cm shorter, which may
be
advantageous in some applications.
[0089] Thus, a novel telescoping camera crane and a novel camera
slider have
been shown and described. Changes and substitutions may of course be made
without
departing from the spirit and scope of the invention. The invention,
therefore, should
not be limited, except by the following claims and their equivalents.
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