U.S. patent application number 12/690335 was filed with the patent office on 2010-08-05 for multi-event telescopic platform.
This patent application is currently assigned to TRACK CORP.. Invention is credited to David W. Heatherington, Terry L. Plumert, Dennis V. Rupar, David R. Southwell, Michiel P. van de Ven, John W. Walwood, Donald W. Wisner.
Application Number | 20100192477 12/690335 |
Document ID | / |
Family ID | 42396545 |
Filed Date | 2010-08-05 |
United States Patent
Application |
20100192477 |
Kind Code |
A1 |
Wisner; Donald W. ; et
al. |
August 5, 2010 |
MULTI-EVENT TELESCOPIC PLATFORM
Abstract
A platform system includes swing arms for moving the platform
from a lowered position to a raised position. In one embodiment, a
pair of swing arms and a pair of telescoping vertical members are
mounted to opposing frame members. The swing arms are capable of
moving from a canted position to a vertical position, which extends
the telescoping vertical members and raises the platform to the
raised position. The swing arms are connected to a drive mechanism
that moves the swing arms from the canted position to the vertical
position. The drive mechanism may include a gear box, and a pair of
lead screws connected to the gear box. The lead screws may extend
from opposing sides of the same gear box, with the gear box
configured to rotate the differently handed lead screws.
Inventors: |
Wisner; Donald W.; (Grand
Haven, MI) ; Southwell; David R.; (Grand Rapids,
MI) ; Heatherington; David W.; (Spring Lake, MI)
; van de Ven; Michiel P.; (West Olive, MI) ;
Rupar; Dennis V.; (Spring Lake, MI) ; Plumert; Terry
L.; (Grand Haven Twp., MI) ; Walwood; John W.;
(Grand Haven, MI) |
Correspondence
Address: |
WARNER NORCROSS & JUDD LLP
900 FIFTH THIRD CENTER, 111 LYON STREET, N.W.
GRAND RAPIDS
MI
49503-2487
US
|
Assignee: |
TRACK CORP.
Spring Lake
MI
|
Family ID: |
42396545 |
Appl. No.: |
12/690335 |
Filed: |
January 20, 2010 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61148513 |
Jan 30, 2009 |
|
|
|
Current U.S.
Class: |
52/10 |
Current CPC
Class: |
E04H 3/123 20130101 |
Class at
Publication: |
52/10 |
International
Class: |
E04H 3/12 20060101
E04H003/12 |
Claims
1. A platform system comprising: a frame; a vertical support member
connected to said frame, said vertical support member being
extendable from a lowered position to a raised position; a platform
connected to said vertical support member; a swing arm connected to
said frame and said vertical support member, said swing arm capable
of pivoting with respect to said frame between a first position and
a second position; and a drive connected to said swing arm, said
drive capable of pivoting said swing arm between said first
position and said second position, said pivoting of said swing arm
between said first position and said second position causing said
vertical support member to move between said lowered position and a
raised position.
2. The platform system of claim 1 wherein said swing arm includes a
nut, said nut receiving a rod connected to said drive and extending
through said nut, wherein said drive is capable of driving said rod
to rotate within said nut, said rotation of said rod within said
nut causing said swing arm to move between said first position and
said second position.
3. The platform system of claim 2 including a pair of said swing
arms and a pair of said rods.
4. The platform system of claim 3 wherein each said swing arm
includes a yoke, said yoke pivotally supporting said nut.
5. The platform system of claim 4 wherein said drive includes a
gear box, said rods connected to said gear box such that said gear
box is capable of driving said rods to rotate.
6. The platform system of claim 5 wherein a first one of said rods
is threaded in the opposite direction as the other of said rods,
such that rotation of said rods in a first direction by said gear
box causes both of said nuts to move away from said gear box.
7. The platform system of claim 6 wherein said swing arms each
define a length, said length of said swing arms being greater than
the length of said telescoping vertical support in said lowered
position, such that a load on said platform is supported by said
swing arms and not said vertical support when said swing arms are
in said second position.
8. The platform system of claim 7 wherein an angle between said
swing arm in said first position and said vertical support member
is less than 60 degrees.
9. The platform system of claim 8 wherein said vertical support
includes a stop member extending therefrom, said stop member
engaging one of said swing arms in said second position to prevent
said one of said swing arms from pivoting past vertical.
10. The platform system of claim 9 wherein said platform is
cantilever mounted to said vertical support.
11. A variable rise platform system comprising: a telescoping
support member, said telescoping support member capable of
extending from a lowered position to a raised position; a load
supporting platform connected to said telescoping support member
such that it is movable with said telescoping support member; a
swing arm connected to said platform, said swing arm having a first
end and a second end, said first end connected to said platform,
said swing arm capable of pivoting about said second end between a
canted position and a vertical position, wherein movement of said
swing arm from said canted position to said vertical position moves
said telescoping support member from said lowered position to said
raised position; and a gear box connected to said swing arm, said
gear box capable of being driven to move said swing arm between
said first position and said second position.
12. The variable rise platform of claim 11 including a frame member
supporting said telescoping support member and said swing arm, said
second end of said swing arm pivotally connected to said frame
member.
13. The variable rise platform of claim 11 including a first lead
screw connected to said gear box, said gear box operable to rotate
said lead screw.
14. The variable rise platform of claim 13 wherein said swing arm a
lead screw nut pivotally connected to first end of said swing arm,
said lead screw nut receiving said first lead screw, such that
rotation of said lead screw causes said lead screw nut to travel
along said first lead screw, whereby said swing arm moves from said
first position to said second position.
15. The variable rise platform of claim 14 including two said swing
arms and two said vertical members, a first one of said swing arms
mounted to said frame proximate a first one of said vertical
members, a second one of said swing arms mounted to said frame
proximate a second one of said vertical members.
16. The variable rise platform of claim 15 wherein a first one of
said swing arms includes a lead screw nut receiving said first lead
screw and a second one of said swing arms includes a lead screw nut
receiving a second lead screw.
17. The variable rise platform of claim 16 wherein said platform
system defines a width between said first one of said vertical
members and said second one of said vertical members, said swing
arms extending past a midpoint of said width when said swing
members are in said canted position.
18. The variable rise platform of claim 17 wherein said first one
of said swing arms is offset from said second one of said swing
arms to provide clearance for said swing arms to overlap each other
when in said canted position.
19. The variable rise platform of claim 18 wherein said second lead
screw is connected to said first lead screw such that rotation of
said first lead screw rotates said second lead screw.
20. A variable rise platform comprising: a platform; first and
second spaced apart frame members; first and second vertical
support members supporting said platform, said first vertical
support member extending upwardly from said first frame member,
said second vertical support member extending upwardly from said
second frame member, said first and second vertical support members
capable of extending from a lowered position to an elongated,
raised position; first and second swing arms, said first swing arm
extending between said first frame member and said platform, said
second swing arm extending between said second frame member and
said platform, said swing arms being longer than said vertical
support members in their lowered position; a gear box; first and
second lead screws connected to said gear box, said gear box
capable of driving said first and second lead screws to rotate;
first and second lead screw nuts, said first lead screw nut
pivotally mounted to said first swing arm, said second lead screw
nut pivotally mounted to said second swing arm, said first lead
screw extending through said first lead screw nut, said second lead
screw extending through said second lead screw nut, wherein
rotation of said lead screws within said lead screw nuts causes
said lead screw nuts to travel along said lead screws, whereby said
swing arms move from a canted position to an upright position,
moving said vertical support members from said lowered position to
said raised position.
Description
BACKGROUND OF THE INVENTION
[0001] The present invention relates to platform seating
assemblies, and more particularly to a system for raising,
lowering, and storing one or more components of a platform seating
assembly.
[0002] Platform seating assemblies are well known for providing
seating accommodations for multiple people, often in large
capacities such as at sporting events. These systems typically
include a platform that provides a seating surface, and a base
support structure that supports the platform at a desired height.
In some cases, the platform is configured for users to sit directly
on the upper surface--commonly known as bleachers--whereas in other
cases, the platform is configured to receive individual seats
attached to the upper surface of the platform. In many applications
multiple platforms are provided at increasing heights to increase
the number of seats at a particular venue and to provide each
platform with an unobstructed forward view. The support structures
of each platform often include wheels, which enable the platforms
to be nested within each other to increase available floor space
when not in use.
[0003] A number of systems exist for raising and lowering the
platforms of a platform seating assembly to desired heights,
including the lift mechanisms shown in U.S. Pat. No. 5,513,976,
U.S. Pat. No. 5,517,789, U.S. Pat. No. 6,243,991, U.S. Pat. No.
6,324,790, U.S. Pat. No. 6,625,932 and U.S. Pat. No. 6,615,548.
Examples of these systems include a scissor lift, a vertical
hydraulic/pneumatic lead screw lift system and a vertical screw
lift system. The scissor lift system includes one or more pairs of
cross members that extend between a support frame and the platform.
The ends of the cross members can be driven closer together to
raise the platform. The scissor lift provides lift while minimizing
the initial height of the system; however, it suffers from a number
of drawbacks. For instance, there are limits on the number of
platforms that this system can lift because the lift system must be
able to support live loads (i.e., the lift system must be able to
support the weight of the platforms and any people on the platforms
in the raised position). In addition, it is a complicated system
and therefore tends to be costly. Similar drawbacks exist for
vertical hydraulic and pneumatic lead screw lift systems, and for
other lift systems, in that they provide direct vertical lift to
the platform which requires them to support the lift system and
live loads. Without an additional locking mechanism, the platforms
supported by these lift mechanisms may collapse upon a failure of
the lift mechanism.
[0004] In addition, easily adjustable platform seating is becoming
increasingly desirable in a number of specific applications. For
instance, some sporting events, such as ice hockey, benefit from a
steeper rise from platform to platform to enable people sitting on
each level to view the ice. In other applications, such as
basketball events, it is desirable to provide additional seating in
front of the hockey dasher board that extends up to the courtside
with a lower degree of rise to accommodate multiple rows of higher
priced portable courtside seats.
SUMMARY OF THE INVENTION
[0005] The present invention provides a platform system that
includes swing arms for moving the vertical support members and the
platform from a lowered position to a raised position.
[0006] In one embodiment, a pair of swing arms and a pair of
telescoping vertical members are mounted to opposing frame members.
The swing arms are capable of moving from a canted position to a
vertical position, which extends the telescoping vertical members
and raises the platform to the raised position. The swing arms are
connected to a drive mechanism that moves the swing arms from the
canted position to the vertical position.
[0007] In one embodiment, the drive mechanism includes a gear box,
and a pair of lead screws connected to the gear box. The lead
screws extend through lead screw nuts on the ends of the swing
arms. The drive mechanism and gear box are capable of rotating the
lead screws within the lead screw nuts, causing the lead screw nuts
to travel along the lead screws. The lead screws may be handed
differently, so that both of the lead screw nuts travel outwardly
when the leads screws rotate, the lead screws moving the swing arms
from the canted position to the vertical position.
[0008] The lead screws may extend from opposing sides of the same
gear box, with the gear box configured to rotate the differently
handed lead screws. Activation of the single gear box thereby
causes both swing arms to move toward the vertical position. In
another embodiment, only a first one of the lead screws is
connected to the gear box, with the other lead screw connected to
the first lead screw. In this embodiment, the swing arms may be
long enough to extend beyond the mid-point of the platform to
overlap each other when in the canted position. The longer swing
arms may increase the height of the platform in the raised
position. In yet another embodiment, each lead screw may be
connected to a separate gear box.
[0009] The benefits of the proposed system are based on simplistic
design, light weight construction and simplicity associated with
operating. In the present invention, structural and live loading is
supported by the swing arms when the platform is in the raised
position. As a result, the loads need not be supported by the lift
mechanism like they are in a vertical lifting lead screw or a
scissor lift system. The telescoping verticals support members may
be used for alignment purposes only, and are not required for load
bearing when the platform system is in the raised position. In
addition, the present system enables individual platforms to be
independently raised and lowered, and only a low torque rotational
tool, such as a handheld drill, is required to operate the gear
box.
BRIEF DESCRIPTION OF THE DRAWINGS
[0010] FIG. 1 is a perspective view of a platform system according
to one embodiment of the present invention, wherein three platforms
are in a lowered position.
[0011] FIG. 2 is a perspective view of a platform system according
to another embodiment of the present invention, wherein the
platform is in a lowered position.
[0012] FIG. 2a is a bottom perspective view of the platform system
of claim 2, wherein the platform is in a raised position.
[0013] FIG. 2b is a close up view of the portion of the platform
system within circle "A" in FIG. 2a.
[0014] FIG. 3 is a perspective view of a telescoping platform
according to the embodiment shown in FIG. 1.
DETAILED DESCRIPTION OF THE CURRENT EMBODIMENTS
I. Overview
[0015] A variable rise platform seating system according to one
embodiment of the present invention is shown in FIG. 1 and
generally designated 10. In general, the described embodiment uses
a swing arm mechanism to lift the deck surface of a telescopic
platform. As shown in FIG. 1, each platform seating system 10
includes a generally horizontal platform deck 12 attached to a
support structure 14. The support structure 14 may be movable, such
that multiple platform systems 10 can be moved between an extended
position (shown in FIG. 1) and a retracted position (not shown) in
which the platform decks 12 and their support structures 14 are
nested with each other. Each platform system 10 is capable of
vertical movement between a lowered position, shown in FIG. 2, and
a raised position, shown in FIG. 2a. The platform system 10 is
moved between the raised and lowered positions by movement of swing
arms between a canted position and a vertical position.
II. Structure
[0016] The support structure 14 for each deck 12 typically includes
a pair of horizontal support members 18 and a pair of vertical
support members 20 extending upwardly from the horizontal support
members 18. In one embodiment (see FIG. 2a), each vertical support
member 20 includes a lower member 22 and an upper member 24. The
upper member 24 extends over the lower member 22 such that they can
extend and retract in a telescoping relationship. Other known
telescoping arrangements or extendable arrangements may
alternatively be used. The horizontal support members 18 may each
include one or more wheels 26 that enable the support structure 14
for each deck 12 to move independently. The upper end 32 of each
vertical support members 20 may provide cantilevered support for a
deck 12 attached to that vertical support 20, as well as providing
vertical load bearing support for the adjacent deck 12. As
illustrated, the upper end 32 of each vertical support member 20 is
secured to a rail 34, which is secured to the edge portion 36 of a
deck 12. In addition, an extension member 38 may extend upwardly
from the upper end 32 of each vertical support member 20 to provide
vertical load bearing support for the adjacent deck 12. Additional
support members 40 may be secured to the rail 34 and the deck 12 to
provide additional support for the deck 12. In one embodiment, a
stop member 42 extends horizontally from each vertical support
member 14 to provide a stop for the swing arms 62 and 64, discussed
below. In the illustrated embodiment, the horizontal 18 and
vertical 20 support members are positioned outboard and towards the
opposing side edges 28, 30 of the decks 12. The support members 18,
20 are positioned so that when multiple support structures 14 and
decks 12 are in the retracted position, the support structures 14
are nested with each other, with the support structures 14
associated with the higher decks 12 being positioned furthest
outboard. The nesting of the support structures 14 is what allows
the telescopic platform system 10 to retract to a depth equal to
the depth of a single deck 12.
[0017] In one embodiment, the present invention utilizes a swing
arm mechanism 48, separate from the vertical support members 20,
for moving each deck 12 between a raised position in which the
telescoping vertical members 20 are fully extended, and a lowered
position in which the telescoping vertical members 20 are fully
retracted. For instance, in one embodiment, it may be desirable to
lower each of the platforms in a platform seating system when the
system is to be moved into the retracted position, to reduce the
space required for the retracted system. It may further be
desirable to raise one or more of the individual platforms when the
platform seating system is in the extended position, in order to
position the platforms at a desired viewing height. In the
illustrated embodiment, the placement of the support structure
requires that the platforms are moved to the lowered position
before they are retracted and nested within each other.
[0018] One embodiment of the swing arm mechanism 48 for raising and
lowering the deck 12 of a platform seating system 10 is shown in
FIGS. 2 and 2a. In this embodiment, the swing arm mechanism 48
includes a pair of horizontally aligned lead screws 54, 56 for
raising and lowering the individual platform to a desired height.
The horizontal lead screws 54, 56 may each be threaded (not shown)
such that they are handed differently (i.e., the lead screw 54 is
handed in a first direction and the lead screw 56 is handed in the
opposite direction) and they may be connected to a common gear box
60--although separate gear boxes may be used. The gear box 60 is
configured to accept both a left hand on a first side of the gear
box 60 and a right hand thread on a second side of the gear box 60,
such that it may drive one of the lead screws 54, 56 on one side of
the gear box and the other lead screw 54, 56 on the opposing side
of the gear box. As a result, single rotation of the gear box 60
causes the two horizontal lead screws 54, 56 to rotate in different
directions. The gear box 60 may be driven by a variety of
conventional drive mechanisms. In one embodiment, the gear box 60
may be driven by a conventional rotational drive tool, such as a
handheld drill. In another embodiment, the gear box 60 is connected
to a separate drive mechanism by a belt drive or another linking
method. The gear boxes 60 of multiple decks 12 may be independently
operated, or they may be linked to a common drive. In yet another
embodiment, each gear box 60 includes a uniquely associated drive
mechanism.
[0019] As illustrated, the swing arm mechanism 48 includes a pair
of swing arms 62, 64, with each swing arm 62, 64 having an upper
end 66 and a lower end 68. The lower end 68 is pivotally connected
to the structural support 18. More particularly, the lower end 68
of each swing arm is pivotally connected to one of the horizontal
support members 18 with a clevis 70 and a pin 72 extending through
the clevis 70 and the lower end 68 of the swing arm 62, 64. This
arrangement allows the swing arm 62, 64 to pivot about the pin 72.
Referring now to FIG. 2B, the upper ends 66 of each swing arm 62,
64 may each attach to one of the horizontal lead screws 54, 56 with
a yoke 74 mounted to the upper end 66 of each swing arm 62, 64. In
one embodiment, each yoke 74 includes a lead screw nut 76 for
receiving one of the lead screws 54, 56. The lead screw nut 76 may
be pivotally mounted to the yoke 74, and may include internal
threads that interfit with the threads of the lead screws 54, 56
such that rotation of the lead screw 54, 56 drives the nut 76 to
move along the lead screw 54, 56. Guide rollers 78 are positioned
on both sides of the yoke 74 and may be used to guide the direction
of the swing arms 62, 64 as the gear box 60 and lead screws 54, 56
are driven. In one embodiment, the rollers 78 ride along a
horizontal track 80 that is positioned off the back of the deck 12
to guide the swing arms 62, 64 as they move from a canted position
to a vertical position. As shown, the horizontal track is supported
by the vertical support members 20 and by cantilevered members 82
that are attached to each deck 12. In one embodiment, the length of
the swing arms 62, 64 is at least the same as the length of the
upper 24 or lower 22 vertical support members, so that the swing
arms 62, 64 are long enough to raise the deck 12 when they are
moved to a vertical position.
[0020] The amount of lift of the platform system 10 (i.e., the
distance that the platform system moves between the lowered and the
raised positioned) is a function of the height of the vertical
support members section 20, the length of the swing arms 62, 64,
and the angle of the swing arms 62, 64 in the lowered position. In
one embodiment, the angle .theta. of the swing arm in the lowered
position (shown in FIG. 2), when measured with respect to the
vertical, is not greater than 60 degrees. An angle greater than 60
degrees may require more than a desired amount of torque to
initiate movement of the swing arm from a canted position to a
vertical position. Although the design of the illustrated
embodiment includes two swing arms (one on each end of the
platform) to create the telescoping of the vertical members, it is
possible to create a telescoping structure that uses only a single
swing arm, or more than one swing arm for each of the vertical
members. For example, in one embodiment, each vertical member may
include two telescoping sections and two swing arms, with one swing
arm connected to each telescoping section. Additional swing arms
would allow for greater lift height on a shorter tier and at the
same time maintain swing arm-to-vertical angles less than 60
degrees. It should also be noted that the angle of the swing arm
62, 64 with respect to the vertical and with respect to the amount
of lift possible is also related to the horizontal spacing between
the rolling frames.
[0021] The support structure 14 may include a variety of additional
support members to aid in supporting a load on the deck 12. For
instance, in one embodiment, the support structure 14 includes a
cross member 90 extending between the horizontal support members,
and a pair of angular members 92, 94 extending between the upper
vertical support members 24 and the deck supports 40. Additional
support members may be added to accommodate additional loads, and
the type and number of support members may very from application to
application.
[0022] An alternative embodiment of the swing arm mechanism 148 is
shown in FIGS. 1 and 3. This embodiment, which is designed for use
with the taller tiers, makes it possible to maintain a swing arm to
vertical angle of less than 60 degrees and at the same time have
elongated swing arms that are capable of lift height of the deck
12. In this configuration, the swing arms 162, 164 are elongated
such that the extend beyond the midpoint of the deck 12 when they
are in the lowered position. The swing arms 162, 164 therefore
overlap each other when in the lowered position. As shown in FIG.
3, in this embodiment, the system 10 may include two separate lead
screws 154, 156, with each swing arm connected to a separate
horizontal lead screw 154, 156. The swing arms 162, 164 may engage
the lead screws 154, 156 with a yoke 74 and lead screw nut 76 in
the same manner as in the first embodiment. The lift mechanism of
FIG. 3 differs in operation when compared to the embodiment
depicted in FIGS. 2 and 2a, because the swing arms of the FIG. 2
embodiment do not travel past the center of the platform. The swing
arms 162, 164 may be positioned in different planes to allow the
swing arms 162, 164 clearance to pass each other as they travel
through the platform center position. For instance, one of the
swing arms 162 is positioned more rearward on the horizontal
support member 18, such that the swing arms 162, 164 are offset
with respect to one another. As in the first embodiment, the
connection point of the swing arms 162, 164 to the horizontal
support member 18 is also the pivot point that permits the swing
arms 162, 164 to rotate from a canted position to a vertical
position. In one embodiment, one of the horizontal support members
18 includes a vertical extension member 130 extending upwardly from
the horizontal support member 18, such that the location in which
the swing arm 162 attaches to the support structure 114 differs in
height from the location in which the other swing arm 164 connected
to the support structure 114 so as to allow the various platforms
to nest when the platform system 10 is in a retracted position. The
two horizontal lead screws 154, 156 may be configured such that one
has a left handed thread (not shown) and the other has a right
handed thread (not shown). A single gear box 160 may be used to
drive the two lead screws 154, 156, with an additional set of gears
165 and a chain or other link member (not shown) used to transfer
the rotation of the driven gear box 160 from one lead screw 154 to
the other lead screw 156. In another embodiment, separate gear
boxes may be used for each lead screw.
III. Operation
[0023] Operation of the platform system 10 to move the deck 12 from
the lowered position to the raised position, or vice versa,
includes activating the drive mechanism to drive the gear box 60
(or 160) and thus rotate the lead screws 54, 56 (or 154, 156).
Activation of the drive mechanism may be initiated by a variety of
conventional methods, such as a switch mounted to the platform
system or mounted separate from the platform system but in
electrical communication with the drive mechanism. When the deck 12
is in the lowered position, such as that shown in FIG. 2, the swing
arms 62, 64 are in a canted position, with the upper ends of the
swing arms 66 spaced from the vertical support members 20. The
vertical support members 20 are therefore in a retracted position,
with the upper member 24 extending over the lower member 22.
Rotation of the lead screws 54, 56 causes each lead screw 54, 56 to
rotate within its associated lead screw nut 76, causing the lead
screw nuts 76 to travel along the lead screws 54, 56 outwardly
toward the vertical support members 20. The outward movement of the
swing arms 62, 64 (or 162, 164) from a canted position to an
upright position causes the telescoping vertical members 20 to
extend, and the deck 12 to move upwardly. The swing arms 62, 64 may
continue to move outwardly until they are in a fully vertical
position, such as that shown in FIG. 2a. The swing arms 62, 64 may
be prevented from over-rotating beyond the vertical position by
adding a stop to horizontal members 42 on each vertical support
member 20. The drive mechanism may be configured to deactivate when
the swing arms 62, 64 reach the vertical position. In the
illustrated embodiment, the swing arms 62, 64 seat directly under
horizontal member 42 because the shaft connected to the pivoting
lead screw nut 76 and the guide rollers 78 passes through a slot in
the yoke bracket 74. This slot allows for vertical movement of the
lead screw nut 76 while the swing arm travels through an arc from
the canted position to vertical position.
[0024] In a lowered position, all loading associated with live load
and deck 12 weight is directed down the vertical members 20 to the
horizontal support members 18. This type of loading scheme is
generally identical in form to what is used for standard telescopic
platforms that do not offer vertical rise. In a raised position,
the swing arms 62, 64 are moved from a canted position to a
vertical position. The swing arms are positioned on the horizontal
support members 18 directly behind the telescoping verticals. As
the swing arms 62, 64 move from a canted position to a vertical
position, the telescoping verticals 20 are extended. The
telescoping verticals 20 provide directional guidance while the
swing arms 62, 64 move from the canted position to the vertical
position. When the swing arms 62, 64 are in the vertical position,
the swing arms 62, 64 take all vertical loading from the individual
tiers. In other words, the load is transferred from the vertical
supports 20 to the swing arms 62, 64 when the swing arms 62, 64 are
in the vertical position. This may include all structural weight
and all live loads. Any loads may also be transferred from lead
screws 54, 56, yokes 74, lead screw nuts 76, and the gear box 60
when the swing arms are in the vertical position. Operation of the
swing arm embodiment shown in FIGS. 1 and 3 is similar to the
operation of the swing arms 62, 64, except that the swing arms 162,
164 travel past each other as they move toward the vertical
position.
[0025] The above description is that of the current embodiments of
the invention. Various alterations and changes can be made without
departing from the spirit and broader aspects of the invention as
defined in the appended claims, which are to be interpreted in
accordance with the principles of patent law including the doctrine
of equivalents. Any reference to claim elements in the singular,
for example, using the articles "a," "an," "the" or "said," is not
to be construed as limiting the element to the singular.
* * * * *