U.S. patent application number 10/208519 was filed with the patent office on 2003-04-24 for switcher track and sled.
Invention is credited to Hotchkiss, Mark, Jayes, Simon T., Spielberg, Steven.
Application Number | 20030075070 10/208519 |
Document ID | / |
Family ID | 26903262 |
Filed Date | 2003-04-24 |
United States Patent
Application |
20030075070 |
Kind Code |
A1 |
Spielberg, Steven ; et
al. |
April 24, 2003 |
Switcher track and sled
Abstract
A switcher track apparatus comprising four switch units having
precisely supported turntables at the intersections of the rails of
two tracks, with switch sections of the track on the turntables
movable into alternate switching positions in alignment with the
two tracks and with magnet assemblies for establishing and
releasably holding precise alignment. A dolly or sled for riding on
the tracks has four wheel assemblies at its corners each comprising
two rows of four roller wheels in a V-shaped arrangement for
engagement with curved rail surfaces. The wheel assemblies are
carried on sprockets that are tied to a driver sprocket on a T-bar
for operation in unison.
Inventors: |
Spielberg, Steven; (Los
Angeles, CA) ; Jayes, Simon T.; (Studio City, CA)
; Hotchkiss, Mark; (Long Beach, CA) |
Correspondence
Address: |
Thomas M. Small, Esq.
BIRCH, STEWART, KOLASCH & BIRCH, LLP
18th Floor
10940 Wilshire Boulevard
Los Angeles
CA
90024
US
|
Family ID: |
26903262 |
Appl. No.: |
10/208519 |
Filed: |
July 30, 2002 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
60335661 |
Oct 24, 2001 |
|
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Current U.S.
Class: |
104/130.01 |
Current CPC
Class: |
E01B 23/06 20130101 |
Class at
Publication: |
104/130.01 |
International
Class: |
E01B 025/06 |
Claims
We claim as our invention:
1. A switcher track assembly for use with two intersecting tracks
having parallel rails and a sled having four wheel assemblies for
riding on the tracks, comprising: four switch units positionable at
the intersections of said rails to lie under the wheel assemblies
of the sled that is positioned over said intersections; each of
said switch units having a rotary turntable with a switching rail
section movable between alternate positions aligned with the
respective tracks; and magnet elements in said switch units
oriented and positioned to move the switching rail sections into
alignment with the respective tracks when the turntables are close
to such alignment, and to maintain the switching rail sections
releasably in precise alignment with the tracks.
2. A switcher track assembly as defined in claim 1 wherein each of
said switch units comprises a generally circular base having four
stub rail sections spaced ninety degrees apart and extending
radially outwardly for connection to said parallel rails of the
intersecting tracks, and said turntables are circular and disposed
over said bases with said switching rail sections alignable
alternately with different switching rail sections.
3. A switcher track assembly as defined in claim 2 wherein said
magnet elements comprise at least one first permanent magnet
mounted on each of said bases beneath the turntable thereof and at
least one second magnet element mounted in the turntable above the
base.
4. A switcher track assembly as defined in claim 3 wherein two of
said first permanent magnets are recessed in recesses in said base,
and a plurality of said second magnet elements are recessed in said
turntable.
5. A switcher track assembly as defined in claim 1 further
including a sled having four wheel assemblies for riding on the
tracks and being positioned on said switcher units to be switched
from one of the tracks to another, each of said wheel assemblies
comprising a plurality of roller wheels disposed in two rows of
wheels rotatably mounted on a carrier on said sled, said carrier
being rotatably supported on the sled for turning of the wheel
assembly into alignment alternately with the rails of the two
tracks.
6. A switcher track assembly as defined in claim 5 wherein each
wheel assembly comprises two rows of four wheels each, mounted on
said carrier for rotation about axes that are angularly spaced so
that the two rows of wheels define an elongated V-shaped groove for
engagement with the rails.
7. A switcher track assembly as defined in claim 6 wherein said
axes are spaced about ninety degrees apart.
8. A switcher track assembly as defined in claim 5 further
including a chain-and-sprocket positioning mechanism for the wheel
assemblies comprising a driver sprocket and four driven sprockets
at the corners of said sled, an operator on the sled for turning
the driver sprocket, and an endless chain connecting the sprockets
for movement in unison, the driven sprockets having shafts
supporting the wheel assemblies on the sled.
9. A sled for use with a switcher track assembly having switch
units at the intersections of the rails of two intersecting tracks,
said sled comprising: a rectangular body forming a platform for
carrying a load along the tracks; and four wheel assemblies beneath
the platform for riding on the tracks and to be positioned on the
switch units at the intersections to be switched from one of the
tracks to another; each of said wheel assemblies comprising a
plurality of roller wheels rotatably mounted on a carrier on said
sled, said carrier being rotatably supported on the sled for
turning of the wheel assembly into alignment alternately with the
rails of the two tracks.
10. A sled as defined in claim 9 wherein each wheel assembly
comprises two rows of four wheels each, mounted on said carrier for
rotation about axes that are angularly spaced so that the two rows
of wheels define an elongated V-shaped groove for engagement with
the rails.
11. A sled as defined in claim 10 wherein said axes are spaced
about ninety degrees apart.
12. A sled as defined in claim 9 further including a
chain-and-sprocket positioning mechanism for the wheel assemblies
comprising a driver sprocket and four driven sprockets at the
corners of said sled, an operator on the sled for turning the
driver sprocket, and an endless chain connecting the sprockets for
movement in unison, the driven sprockets having shafts supporting
the wheel assemblies on the sled.
Description
REFERENCE TO RELATED APPLICATION
[0001] This application claims priority based upon copending U.S.
provisional application Serial No. 60/335,661, filed Oct. 24, 2001,
entitled "Switcher Track and Sled".
BACKGROUND OF THE INVENTION
[0002] This invention relates to a track apparatus for supporting
and moving a wheeled dolly or sled and switching the dolly or sled
from one set of parallel tracks to another set of intersecting
tracks, and also relates to an improved dolly or sled for use on
such a track apparatus, having wheels that are turnable from
alignment with one set of tracks into alignment with the other set.
The invention has particular reference to such a track apparatus
and dolly or sled for use in connection with motion picture
photography, or cinematography, wherein track-mounted
motion-picture cameras are used to film scenes from different
points along a track path or in motion along a track.
[0003] A prior track apparatus of this general type is shown in
U.S. application Ser. No. 09/031,713 corresponding to application
No. PCT/US00/04000, filed Feb. 16, 2000, and a switch unit for that
apparatus also is shown in U.S. Patent No. Des. 401951. The present
invention is an improvement over the track apparatus and dolly
construction shown in the prior application, which used a
conventional camera dolly with swivel wheels and track switches
that were connected by linkages to transmit the motion of one
switch unit in response to turning of one wheel by an operator or
dolly grip to transmit the motion to the other three switch units
and the wheels of the dolly that rested on those switch units.
SUMMARY OF THE INVENTION
[0004] The present invention resides in an improved track apparatus
with simplified and more precisely positioned switch units that
significantly enhance the smoothness and precision of the switching
operation, and an improved sled or dolly that cooperates with the
track apparatus to facilitate the switching operation and maintain
the smooth and precise positioning of the camera on the track
apparatus.
[0005] For these purposes, the dolly or sled (hereinafter sled) has
a built-in steering system for all of its wheels, in the form of a
chain-and-sprocket control that ties the wheels together for
turning under the positive control of a single operator on the
sled, preferably a T-bar operating handle, and has improved
V-shaped wheel assemblies in the form of gangs of rollers arranged
in two rows to form an elongated V-shaped groove in each wheel
assembly for straddling the track and rolling very smoothly over
the intersections to avoid excessive vibration that would interfere
with the filming.
[0006] The improved switches have turntables and bases with
precisely intermitting, circular bearing surfaces for smooth
rotation and solid support for each wheel assembly, and have
permanent magnet assemblies that are embedded in the turntables and
the bases with the polarities arranged to force the turntables into
properly aligned positions with respect to the tracks in the
alternate switching positions. As the turntables are turned by the
sled wheel assemblies under the control of the operator from one
track to the other, the magnetic fields of the magnets force the
turntables into precisely aligned positions and then hold the
turntables magnetically in those positions until the operator
overcomes the magnetic force and moves the turntables out of the
aligned positions toward the alternate positions.
[0007] Other more detailed aspects and advantages of the invention
will be apparent from the accompanying drawings and the following
detailed description.
BRIEF DESCRIPTION OF THE DRAWINGS
[0008] FIG. 1 is an exploded fragmentary perspective view of a
switch assembly at an intersection of two tracks, and a sled for
riding on those tracks and supporting a cinematographer (not
shown);
[0009] FIG. 2 is a somewhat enlarged fragmentary bottom perspective
view of the sled of FIG. 1;
[0010] FIG. 3 is a top plan view of the sled;
[0011] FIG. 4 is a bottom plan view of the sled;
[0012] FIG. 5 is a top perspective view of one of the switch units
of the switch assembly of FIG. 1, with the turntable in a turned
position;
[0013] FIG. 6 is an exploded perspective view of the switch unit in
FIG. 5, taken from the right hand side thereof;
[0014] FIG. 7 is a further exploded perspective view of the switch
unit in FIG. 6, showing the underside of the turntable and the
positions of the magnets of the unit; and
[0015] FIG. 8 is a top perspective view of the switch assembly of
FIG. 1 with the turntables shown in misaligned positions (spaced
from the alternate positions controlled by the magnets) this being
a condition that could exist as the wheel assemblies are in the
process of turning from alignment with one track to the other.
DETAILED DESCRIPTION OF THE PRESENTLY PREFERRED EMBODIMENT
[0016] As shown in the drawings for purposes of illustration, the
invention is embodied in a switch assembly, indicated generally by
the reference number 10 in the drawings, for connecting two tracks
11 and 12 comprising parallel rails 13, and a sled 14 having wheel
assemblies 15 for riding on the tracks and being switched from one
track to the other by the switch assembly. The illustrative sled
has a generally rectangular frame forming a flat platform or body,
and four wheel assemblies 15 beneath the four corners of the
platform. The switch assembly has four switch units, each indicated
generally by number 17, positioned to lie under the four wheel
assemblies 15 when the sled is positioned over the intersection of
the two tracks.
[0017] As can be seen in FIG. 1, each of the tracks 11 and 12 is
formed by two elongated rails 13 that are held in spaced, parallel
relation by transverse braces 18. The rails can be formed in
sections (not shown) joined together in end-to-end relation to
cover whatever range of motion is desired for a particular filming
project, and can form "through" intersections as well as corner
intersections of the kind shown in FIG. 1. Right-angle
intersections are typical, but other angles can be accommodated by
adapting the equipment to those angles.
[0018] The illustrative rails 13 have upper edges that are shaped
for engagement with the wheel assemblies 15, herein being rounded
as best seen in FIGS. 5 to 7 on the stub abutment sections 19 and
20 shown on the switch units 17 in those views. These abutment
sections engage, and merge smoothly with, the rails 13, and also
with switching sections 21 of the rails that are mounted on the
switch units to extend between aligned pairs of the abutment
sections 19 and 20 on the units, as will be described. A central
brace unit 22 (FIG. 1) or 23 (FIG. 8) is provided to be secured to
the four switch units 17, with various combinations of stub units
and extension sections (not shown) to hold the switch units in the
desired pattern for engagement with the wheel assemblies 15 of the
sled 14. Pins 24 are provided to join the various rail sections
together.
[0019] The illustrative sled 14 has a rigid platform and special
wheel assemblies 15 that are designed to provide solid, firm and
virtually vibration-free support for a camera or camera operator
(not shown) supported on the sled for movement along one of the
tracks 11 or 12, as more fully illustrated in the aforesaid PCT
patent application. As can be seen in FIGS. 1 through 4, the
platform is constructed as a grid of lightweight longitudinal and
transverse tubular beams 25 and 27 respectively, that are pinned or
welded together in a very solid construction to provide a flat top
for supporting the load to be carried along the track, and with a
central extension 28 mounted on one end, the right hand end in FIG.
1, between the protruding ends of two longitudinal beams 25. This
provides an out-of-the-way support for the operator, herein a T-bar
operating handle 29 that extends upwardly from a driving sprocket
assembly 30 that is rotatably mounted in the platform extension
28.
[0020] At each corner of the platform, a driven sprocket assembly
31 is mounted between the laterally protruding ends of two
transverse beams 27 with the central axle of the sprocket assembly
vertical, that is, parallel to the axis of the T-bar handle 29, and
extending downwardly beneath the platform to support one of the
wheel assemblies 15. The wheel assembly is carried on the lower end
of the sprocket axle and thus is rotatable with the axle relative
to the platform.
[0021] Connecting the T-bar driving sprocket 30 to the driven
wheel-assembly sprockets 31 is an endless flexible chain 32, which
also could be a cog belt or other flexible driver. As shown most
clearly in FIG. 3, this chain is trained around the driver sprocket
30, two idler sprockets 33 journaled on the frame under the closest
transverse beam 27, then around the outer side of each of the
adjacent driven sprockets 31. From these sprockets, long runs 32a
of the chain extend to the two driven sprockets 31 at the opposite
end of the platform and around the outer sides of these sprockets
to two tensioning sprockets 34 and 35 that are adjustably mounted
to take up slack in the chain and maintain a preselected amount of
tension. One or both of these tensioning sprockets may be
spring-loaded in a conventional manner to apply the preselected
tension to the chain. All of the sprockets are bearing-mounted to
provide for smooth, low-friction operation in response to turning
of the operating handle 29, and guard tubes or inverted
channel-shaped covers 37 (FIG. 1) may be provided for the runs of
the chain that pass through openings in the platforms, for safety
purposes.
[0022] The wheel assemblies 15 that are carried by the sprocket
axles at the corners of the platform are positioned in a
rectangular pattern that corresponds to the track width to dispose
the pivotal axes of the wheel assemblies in alignment with the
rails 13 of both tracks 11 and 12 when the sled 14 is positioned on
the switch assembly 10 for switching. When the two tracks are of
equal width, as preferred, the wheel-assembly pattern is a square
with equal spacing of the wheel axes both longitudinally and
laterally. Of course, provision can be made for switching on tracks
of different widths, in which case the wheel axis pattern would be
a rectangle other than a square.
[0023] As shown most clearly in FIG. 2, the wheel assemblies 15
comprise a plurality of bearing-supported roller wheels 38, herein
four, in each of two rows of such wheels, rotatably mounted on
individual axles that are supported on carriers 39 (FIG. 2) of
V-shaped cross-sectional shape forming the bodies of the wheels.
These carriers herein are lengths of angle iron with two sides
disposed at ninety degrees, and the wheel axles are perpendicular
to the sides of the angle iron so that the wheels 38 of the two
rows define a V-shaped groove for straddling one of the rails 13.
Blocks with beveled edges also can be used as carriers, with the
same effect. The wheels ride along opposite sides of the curved
upper end of the rail, engaging a substantial length of the rail to
provide solid support and to minimize vibrations created by any
irregularity in the track. The angle-iron wheel carriers 39 thus
are turnable about the axes of the corner sprocket axles for
switching of the sled from one track to the other by the switch
assembly 10.
[0024] In FIG. 1, the wheel assemblies 15 and the switching
sections 21 of the switch units 17 are shown in alignment with the
track 11 extending to the right from the switch assembly 10. When
the sled 14 is resting on the switch assembly in this condition, it
can be rolled to the right onto the track 11, and used as desired
for filming along that track, or the wheel assemblies 15 can be
turned by the operator 29 into alignment with the intersecting
track 12, which extends upwardly and slightly to the left as viewed
in FIG. 1. The turntables 40 of the switch units 17 are rotatable
to permit the wheel assemblies to be turned into this new position,
as will be described in more detail. When so turned, the wheel
assemblies 15 will roll onto the track 12 and along the path
defined by that track. This transition will be made smoothly, with
little or no vibration, because of the precise alignment of the
various track sections and the special construction of the wheel
assemblies 15 and the sled 14.
[0025] For such precise alignment, the improved switch units 17 of
the present invention generally comprise the turntables 40, which
are circular in shape with the track sections 21 extending
diametrically across their upper sides, and circular bases 41
having flat undersides for resting on a supporting surface, with
the track stubs 19 and 20 extending radially outwardly at
ninety-degree angles for connection to rails 13 of the intersecting
tracks 11 and 12. The stub sections are of the same size and
cross-sectional shape as the rails 13, to fit flushly against the
ends of the rails and be connected thereto by the pins 24.
[0026] Each of the bases 41 is recessed below the top edges of the
stub sections 19 and 20 to receive the circular turntable 40
between the stub sections with the upper edge of the switching
track section 21 level with upper edges of the stub sections. The
turntable has a flat circular edge 42 that fits closely between the
inner ends of the stub sections, and a generally flat underside
that is centrally recessed and contoured as shown in FIG. 7 to fit
over a bearing ring 43 and a raised cylindrical centerpiece 44 on
the base, so that the flat underside of the turntable will turn
freely and smoothly on the base. A screw 45 extends upwardly
through a bearing 47 (FIG. 6) and a center hole 48 in the base and
is threaded into a center hole 49 (FIG. 7) in the underside of the
turntable 40 to secure the turntable rotatably to the base.
[0027] For magnetic alignment of each turntable 40 in its alternate
switching positions, permanent ring magnets 50 (FIGS. 6 and 7) are
set into circular recesses 51 in the base 41, beneath the turntable
40, to interact with elongated magnet keys 52 (FIG. 7) that are set
into slots 53 in the underside of the turntable. These magnet
elements 50 and 52 are oriented and positioned to cause the
turntable to be forced magnetically into each of the alternate
switching positions shown in FIGS. 1 and 5, the magnet elements
being operable to take over the positioning function as the
switching rail section 21 comes close to the selected switching
position, so that, upon release of the T-bar operator 29, the
precisely aligned positions will be achieved. It will be seen in
FIGS. 6 and 7 that four magnet recesses 51 are formed in the base
41, providing alternate positions for the ring magnets 50. Screws
54 are provided for securing the ring magnets in their recesses,
and turnbuckles 55 are set in holes 57 in the base 41 for secure
positioning of the switching components. All bearings and bearing
surfaces of the base and the turntable are precisely machined and
closely fitted for smooth movement and precise alignment of the
turntables 40.
[0028] From the foregoing, it will be seen that the present
invention provides an improved switcher track 10 and sled 14 for
the purposes that have been described, and other similar purposes
requiring smooth and easy switching from one track to another. It
also will be evident that one embodiment of the present invention
has been illustrated and described, and various changes and
modifications may be made by those skilled in the art within the
scope of the present invention.
* * * * *