U.S. patent application number 13/790650 was filed with the patent office on 2014-09-11 for floating manhole frame assembly.
This patent application is currently assigned to EJ USA, INC.. The applicant listed for this patent is EJ USA, INC.. Invention is credited to Jeremy I. Johnson, Dean W. Reynolds.
Application Number | 20140250794 13/790650 |
Document ID | / |
Family ID | 51486048 |
Filed Date | 2014-09-11 |
United States Patent
Application |
20140250794 |
Kind Code |
A1 |
Reynolds; Dean W. ; et
al. |
September 11, 2014 |
FLOATING MANHOLE FRAME ASSEMBLY
Abstract
A manhole frame assembly according to one embodiment of the
present invention generally includes an upper frame and a lower
frame, and is adapted to support a manhole cover. The upper frame
may be allowed to float with respect to the lower frame, enabling
the upper frame to move during installation, or as the surrounding
structure moves, or both. By being capable of movement, the upper
frame may potentially prevent uneven transitions between the
manhole frame assembly and the surface of the surrounding
structure.
Inventors: |
Reynolds; Dean W.; (Elmira,
MI) ; Johnson; Jeremy I.; (East Jordan, MI) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
EJ USA, INC. |
East Jordan |
MI |
US |
|
|
Assignee: |
EJ USA, INC.
East Jordan
MI
|
Family ID: |
51486048 |
Appl. No.: |
13/790650 |
Filed: |
March 8, 2013 |
Current U.S.
Class: |
49/504 |
Current CPC
Class: |
E02D 29/1409
20130101 |
Class at
Publication: |
49/504 |
International
Class: |
E02D 29/14 20060101
E02D029/14 |
Claims
1. A manhole frame assembly adapted to seat over an opening of an
underground area, the opening providing a passageway for access to
the underground area, said manhole frame assembly adapted to be
installed adjacent a structure, said manhole frame assembly
comprising: a lower frame having a lower peripheral wall and a
base, said base adapted to be fastened in place over the opening,
said lower peripheral wall extending from said base and having a
first inside surface and a first outside surface; an upper frame
adapted to move with respect to said lower frame, said upper frame
having an upper peripheral wall with a second inside surface and a
second outside surface; wherein said upper and lower peripheral
walls define an access opening to the passageway; wherein said
upper frame is adapted to slide over said lower frame such that a
portion of said second inside surface of said upper frame overlaps
a portion of said first outside surface of said lower frame; a
sleeve encircling at least part of said first outside surface of
said lower peripheral wall, wherein a gap is formed between said
sleeve and said at least part of said first outside surface of said
lower peripheral wall; wherein said sleeve is adapted to encircle
at least part of said second outside surface of said upper
peripheral wall, wherein said at least part of said second outside
wall is disposed within said gap formed between said sleeve and
said at least part of said outside surface of said lower peripheral
wall, wherein said sleeve is detached from said upper frame,
wherein said upper frame is capable of moving with respect to said
sleeve, wherein said gap provides clearance between said sleeve and
said at least part of said first outside surface to allow said
upper frame to tilt with respect to said lower frame and said
sleeve; and wherein said upper frame includes one or more flange
projections extending from said second outside surface, wherein
said one or more flange projections are configured to link with the
structure such that movement of the structure results in
corresponding movement of said upper frame.
2. The manhole frame assembly as claimed in claim 1 wherein said
upper frame is capable of moving in response to movements in the
structure, and wherein said sleeve prevents the structure from
binding said portions of said second inside surface and said first
outside surface that overlap.
3. The manhole frame assembly as claimed in claim 1 wherein said
upper frame is capable of moving with respect to said sleeve and
said lower frame during installation of the upper frame.
4. The manhole frame assembly as claimed in claim 1 wherein said
sleeve is rigid.
5. The manhole frame assembly as claimed in claim 1 wherein a
perimeter of said sleeve defines said gap between said sleeve and
said first outside surface of said lower frame, and wherein said
upper peripheral wall is capable of fitting within said gap.
6. The manhole frame assembly as claimed in claim 1 wherein said
sleeve and said lower frame are configured to enable said upper
frame to extend and contract and to tilt with respect to the lower
frame.
7. The manhole frame assembly as claimed in claim 6 wherein in a
fully contracted position, said upper frame contacts said base of
said lower frame preventing further contraction.
8. The manhole frame assembly as claimed in claim 6 wherein said
lower frame, said upper frame, and said sleeve are configured to
allow the upper frame to tilt between 0.degree. and 5.degree. with
respect to said lower frame.
9. The manhole frame assembly as claimed in claim 1 wherein said
lower frame includes an upper surface of the lower peripheral wall,
and further comprising a gasket disposed in proximity to said upper
surface and adapted to provide a seal between the upper peripheral
wall and the lower peripheral wall, said seal substantially
preventing the structure from entering the access opening.
10. (canceled)
11. The manhole frame assembly as claimed in claim 1 wherein said
one or more flange projections include an opening such that a
portion of each of said one or more flange projections is capable
of being enclosed by the structure.
12. (canceled)
13. A manhole frame assembly adapted to seat over an opening of an
underground area, the opening providing a passageway for access to
the underground area, said manhole frame assembly adapted to be
installed adjacent a structure, said manhole frame assembly
comprising: a lower frame having a lower peripheral wall and a
base, said base adapted to be fastened in place over the opening,
said lower peripheral wall extending from said base and having a
first inside surface and a first outside surface; an upper frame
adapted to move with respect to said lower frame in response to
movements in the structure, said upper frame having an upper
peripheral wall, said upper peripheral wall having a second inside
surface and a second outside surface; wherein said upper and lower
peripheral walls define an access opening to the passageway; a
sleeve encircling at least part of said first outside surface of
said lower peripheral wall, a perimeter of said sleeve defining a
gap between said sleeve and said first outside surface, wherein
said upper peripheral wall is capable of fitting within said gap,
wherein said sleeve is detached from said upper frame, wherein said
gap provides clearance between said sleeve and said at least part
of said first outside surface to allow said upper frame to tilt
with respect to said lower frame and said sleeve; wherein said
sleeve maintains said gap to enable said upper frame to move with
respect to the lower frame and to prevent the structure from
binding the upper frame; and wherein said upper frame includes one
or more flange projections extending from said second outside
surface, wherein said one or more flange projections are configured
to link with the structure such that movement of the structure
results in corresponding movement of said upper frame.
14. The manhole frame assembly as claimed in claim 13 wherein said
sleeve is adapted to encircle at least part of said second outside
surface of said upper peripheral wall, wherein said upper frame
moves with respect to said sleeve in response to the movements in
the structure, and wherein said sleeve prevents the structure from
binding a portion of said second inside surface of said upper
peripheral wall that overlaps a portion of said first outside
surface of said lower peripheral wall.
15. The manhole frame assembly as claimed in claim 13 wherein said
upper frame is adapted to slide over said lower frame such that a
portion of said second inside surface of said upper frame overlaps
a portion of said first outside surface of said lower frame.
16. The manhole frame assembly as claimed in claim 13 wherein said
sleeve is rigid.
17. The manhole frame assembly as claimed in claim 13 wherein said
sleeve and said lower frame are configured to enable said upper
frame to extend and contract and to tilt with respect to the lower
frame.
18. The manhole frame assembly as claimed in claim 17 wherein in a
fully contracted position, said upper frame contacts said base of
said lower frame preventing further contraction.
19. The manhole frame assembly as claimed in claim 13 wherein said
lower frame includes an upper surface of the lower peripheral wall,
and further comprising a gasket disposed in proximity to said upper
surface and adapted to provide a seal between said upper peripheral
wall and said lower peripheral wall, said seal substantially
preventing the structure from entering the access opening.
20. (canceled)
21. The manhole frame assembly as claimed in claim 13 wherein said
one or more flange projections include an opening such that a
portion of each of said one or more flange projections is capable
of being encapsulated by the structure.
22. (canceled)
Description
BACKGROUND OF THE INVENTION
[0001] The present invention relates to a floating manhole frame
assembly, and more particularly to a manhole frame assembly
configured to move as the surrounding environment moves.
[0002] Manhole frame assemblies are well known. Generally, a
manhole frame assembly covers an opening providing access to an
underground area also known as a manhole that may include
utilities, pipes, cables and passages. The manhole frame assembly
may be fitted with a cover to, among other things, prevent someone
from falling in and to keep unauthorized persons out. Conventional
manhole frame assemblies include a frame capable of receiving a
cover that limits access to the manhole. The cover is a removable
plate forming the lid over an opening in the frame through which
the underground area may be accessed. The manhole cover seats on
the frame, sometimes flush with the surface of a road. And, the
frame, often times, is secured to the underground area or
surrounding structure, such as a concrete or asphalt concrete road
surface, so that the manhole cover may be removed for access while
the frame remains in place.
[0003] In many instances, the surrounding structure, including the
ground, may shift or move after the manhole frame assembly has been
installed. Thus, even if the manhole frame assembly, when fitted
with a cover, is installed flush with the surrounding surface
(e.g., the road surface), shifts in the surrounding structure may
result in an uneven surface. For example, once such a shift occurs,
portions of the manhole frame assembly may project significantly
above or below the surrounding surface. There are a variety of
events capable of causing shifts in the surrounding structure. One
event, common to the climate of the Midwestern U.S., is freezing
and thawing. As the ground freezes and thaws, the ground may shift
resulting in movement in the roadway or the underground area. The
surrounding surface or roadway, itself, may also shift when frozen
and thawed. Another event, soil erosion, may cause movement in the
surrounding structure as well. These are just two example events;
there are many other events that may result in movement of
surrounding structure or the ground in proximity to the manhole
frame assembly.
[0004] As mentioned previously, many conventional manhole frame
assemblies are unable to move in harmony with the ground or the
surrounding structure. This inability to move is a common drawback
of conventional manhole cover assemblies because it can result in a
rough road surface or an abrupt transition between the surrounding
surface and the manhole frame assembly. Uneven features in the
roadway may increase wear on any vehicles traveling over the
roadway. Smooth transitions on the road surface, on the other hand,
may help to minimize wear on vehicles that travel over the manhole
frame assembly.
SUMMARY OF THE INVENTION
[0005] The present invention provides a manhole frame assembly
configured to seat about an opening of an underground area, and to
be installed adjacent a surrounding structure. The manhole frame
assembly may include a lower frame having a lower peripheral wall
and a base, the base adapted to be fastened in place on the
opening. The manhole frame assembly may also include an upper frame
adapted to move with respect to the lower frame. Movement of the
upper frame may occur in response to movements in the surrounding
structure. In addition to or alternatively, movement of the upper
frame may be conducted during installation to substantially match
the upper frame height to the surface of the surrounding structure.
By being capable of movement, the upper frame may provide a smooth
transition between the surrounding surface and the manhole frame
assembly.
[0006] The manhole frame assembly may also include a sleeve
encircling at least part of the lower frame and capable of
encircling at least part of the upper frame. The sleeve may prevent
the surrounding structure from binding overlapping portions of the
upper and lower frames so that the upper frame is capable of
floating. And, the sleeve may be rigid such that it resists
deflection in response to loading from the surrounding
structure.
[0007] In one embodiment, the sleeve has a perimeter defining a gap
between the sleeve and the lower peripheral wall, where the upper
peripheral wall of the upper frame may fit within the gap. With
this configuration, for example, portions of the upper frame may
slide between the sleeve and the lower frame. The upper frame may
displace vertically with respect to the lower frame, thereby
extending and contracting within the gap. The upper frame may also
tilt with respect to the lower frame. Because the upper frame may
tilt, extend, and contract, the upper frame may float to maintain
smooth transitions between a surface of the surrounding structure
and the manhole frame assembly.
[0008] The gap formed by the sleeve may prevent the surrounding
structure from binding the upper frame to the lower frame. For
example, without the sleeve, the surrounding structure may
sufficiently load the upper frame against the lower frame such that
the upper frame is prevented from floating as intended. The sleeve
may prevent such loading of the upper frame.
[0009] In one embodiment, the upper frame may include a projection
extending from the upper peripheral wall that links with the
surrounding structure. This link may enable movement in the
surrounding structure to be translated to the upper frame, thereby
resulting in the upper frame floating with respect to the lower
frame to maintain appreciably smooth transitions between the
surface of the surrounding structure and the frame assembly.
[0010] The present invention provides an effective manhole frame
assembly that enables part of the frame assembly to move in
response to movement in the surrounding structure. In this way, the
manhole frame assembly may mitigate against abrupt transitions
between the surface of the surrounding structure and the manhole
frame assembly. These and other objects, advantages, and features
of the present invention will be more fully understood and
appreciated by reference to the description of the current
embodiment and the drawings.
[0011] Before the embodiments of the invention are explained in
detail, it is to be understood that the invention is not limited to
the details of operation or to the details of construction and the
arrangement of the components set forth in the following
description or illustrated in the drawings. The invention may be
implemented in various other embodiments and capable of being
practiced or being carried out in alternative ways not expressly
disclosed herein. Also, it is to be understood that the phraseology
and terminology used herein are for the purpose of description and
should not be regarded as limiting. The use of "including" and
"comprising" and variations thereof is meant to encompass the items
listed thereafter and equivalents thereof as well as additional
items and equivalents thereof. Further, enumeration may be used in
the description of various embodiments. Unless otherwise expressly
stated, the use of enumeration should not be construed as limiting
the invention to any specific order or number of components. Nor
should the use of enumeration be construed as excluding from the
scope of the invention any additional steps or components that
might be combined with or into the enumerated steps or
components.
BRIEF DESCRIPTION OF THE DRAWINGS
[0012] FIG. 1 is a top view of a frame assembly according to the
current embodiment.
[0013] FIG. 2 is a sectional view of the frame assembly according
to the current embodiment.
[0014] FIG. 3 is a front view of the frame assembly according to
the current embodiment, showing a tilted upper frame of the frame
assembly.
[0015] FIG. 4 is a side view of the frame assembly according to the
current embodiment, showing vertical displacement of the upper
frame of the frame assembly.
[0016] FIG. 5 is a top view of a sleeve of the frame assembly
according to the current embodiment.
[0017] FIG. 6 is a sectional view of the sleeve of the frame
assembly according to the current embodiment.
DESCRIPTION OF THE CURRENT EMBODIMENT
[0018] A manhole frame assembly according to one embodiment of the
present invention is shown in FIGS. 1-6 and generally designated 8.
The manhole frame assembly 8 generally includes an upper frame 10
and a lower frame 12, and is adapted to support a manhole cover
(not shown). The upper frame 10 in the current embodiment is
allowed to float with respect to the lower frame 12, enabling the
upper frame 10 to move with respect to the lower frame 12 during
installation or as the surrounding structure moves, and potentially
preventing uneven transitions between the manhole frame assembly
and the surface of the surrounding structure. The manhole frame
assembly 8 also includes a sleeve 14 disposed around the perimeter
of the upper frame 10 and the lower frame 12. This sleeve 14 may
shield portions of the upper frame 10 and the lower frame 12 from
the surrounding structure so that the surrounding structure does
not significantly impede movement of the upper frame 10 with
respect to the lower frame 12. In this way, the upper frame 10 may
float, enabling during installation appropriate positioning of the
upper frame 10 with respect to the surrounding surface, or
potentially maintaining a smooth transition between the surrounding
surface and the manhole frame assembly 8, or both. For example, the
sleeve may prevent the surrounding structure from binding
overlapping parts of the upper frame 10 and the lower frame 12.
[0019] The described embodiment may be used as a manhole frame
assembly 8 to cover an access opening 15 of an underground area and
to provide access to an infrastructure, such as a drainage or sewer
infrastructure system, underneath the opening. Although the manhole
frame assembly 8 may be installed over any suitable hole, it will
often be installed over a manhole in a street or sidewalk. As noted
above, the manhole frame assembly 8 according to the current
embodiment includes an upper frame 10, a lower frame 12, and a
sleeve 14.
[0020] In the illustrated embodiments of FIGS. 1-2, the lower frame
12 and the upper frame 10 are peripheral structures. The lower
frame 12 includes a base 34 and a peripheral wall 32, which extends
upwardly from the base 34 and includes an inner surface 38 and an
outer surface 36. In the current embodiment, a gasket 42 may be
disposed on the outer surface 36 of the lower frame 12, providing a
seal between the lower frame 12 and the upper frame 10 that allows
movement of the upper frame 10 while potentially preventing debris
from entering the access opening 15. The gasket 42 may be seated on
an upper surface 40 of the peripheral wall 32 opposite the base 34
so that the gasket 42 stays in place.
[0021] For purposes of disclosure, the described frame assembly 8
is annular and may be installed over an underground area, but it
should be appreciated that the frame assembly 8 may be any shape,
including for example rectangular or square. The upper frame 10 and
lower frame 12 are constructed of cast iron in the current
embodiment. However, that these components may be constructed of
suitable materials other than iron or metal, and manufactured using
established methods of manufacture other than casting. The sleeve
14 in the current embodiment is constructed of steel, but as with
the upper frame 10 and lower frame 12, may be manufacture and
constructed of other suitable materials.
[0022] The lower frame 12 in the current embodiment may also
include one or more flanges 44 capable of coupling to an adjusting
bolt 46 and a bracket 48. The flanges 44 may include a cast-in nut
or may be drilled and tapped to receive the adjusting bolt 46. In
this way, the height of the brackets 48 may be adjusted with
respect to the lower frame 12 by turning the adjusting bolt 46. The
brackets 48 in the current embodiment are capable of interfacing
with and supporting the upper frame 10 at a desired height with
respect to the lower frame 12. The brackets 48 and adjusting bolts
46 in practice are not permanent; rather, they allow the upper
frame 10 and lower frame 12 to be positioned for installation. For
example, because the thickness of the surrounding structure may be
different from one installation site to another, enabling the upper
frame 10 to move relative to the lower frame 12 allows the upper
frame 10 to be installed such that a relatively smooth transition
occurs between the surface of the surrounding structure and the
frame assembly 8. Once the frame assembly 8 has been installed and
the surrounding structure, such as concrete, has cured, the
brackets 48 and adjusting bolts 46 may be removed.
[0023] In the current embodiment, the base 34 of lower frame 12 may
be fastened to an upper portion of the underground area, often
times referred to as a chimney (not shown). The lower frame 12 may
be fastened to the chimney using anchor bolts or angled anchor rods
fastened to either the chimney or the surrounding structure, such
as the road. To mitigate against leaks in the joint between the
chimney and the base 34, a seal (not shown) may be installed near
the periphery of the joint, or disposed between (a) the chimney and
base 34 and (b) the surrounding structure, or between the chimney
and the base 34.
[0024] Turning now to the construction of the upper frame 10
according to the current embodiment, the upper frame 10, like the
lower frame 12, includes an upper frame peripheral wall 50 having
an inner surface 54 and an outer surface 52. The upper frame 10 may
also include a top edge 58 and a cover receiving support 56
configured as a flange on the inner surface 54. The cover receiving
support 56 supports the manhole cover (not shown) in a seated
position. The construction of the top edge 58, inner surface 54,
and cover receiving support 56 may be constructed to interface with
the cover to cover the access opening 15. Although not shown, a
gasket such as a neoprene gasket may be disposed between the cover
and the cover receiving support 56, thereby potentially preventing
debris from entering the access opening 15. The cover receiving
support 56 may also interface with the brackets 48, as shown in
FIG. 2, to support the upper frame 10 above the lower frame 12
during installation.
[0025] In an alternative embodiment, a supporting surface other
than the cover receiving support 56 may support the manhole cover
in a seated position to cover the access opening 15. For example,
the cover may seat on the top edge 58 of the upper frame 10.
[0026] In the illustrated embodiment of FIG. 1, the upper frame 10
includes one or more flange projections 60 extending from the outer
surface 52 of the upper frame 10. The flange projections 60 of the
upper frame 10 may link with the surrounding structure, for
example, by binding with concrete poured around the frame assembly
8 during installation. Slots or openings 62 in the flange
projections 60 may strengthen the link with the surrounding
structure by allowing the surrounding structure to fully
encapsulate a portion of the flange projection. In one embodiment,
with the flange projections linked to the surrounding structure,
the upper frame 10 may float with respect to the lower frame 12 and
movements or shifts occurring in the surrounding structure may be
translated to the upper frame 10. As a result, the upper frame 10
may be capable of moving in tandem with the surrounding structure,
potentially preventing abrupt transitions between the surface of
the surrounding structure and the frame assembly 8.
[0027] For example, as shown in the illustrated embodiment of FIG.
3, the upper frame 10 is allowed to tip or tilt with respect to the
lower frame 12. If the surrounding structure shifts up or down near
a portion of the upper frame 10, this movement may be translated
through the flange projections 60 so that the upper frame 10 tips
accordingly. In the illustrated embodiment, the upper frame 10 is
shown tilted at a maximum tilt angle--5.degree.. It should be
understood that the frame assembly 8 is not limited to a 5.degree.
maximum tilt angle and that the frame assembly 8 may be configured
to increase or decrease the maximum tilt angle. For instance, by
increasing the clearance between the upper frame 10, the lower
frame 12 and the sleeve 14, the maximum tilt angle may be
increased. As perhaps best shown in the cross sectional view of
FIG. 2, the inner surface 54 of the upper frame 10 and the outer
surface 36 of the lower frame 12 may be angled such that the
peripheral wall 32 of the lower frame 12 and the peripheral wall 50
of the upper frame 10 allow for greater clearance and tipping. By
increasing or decreasing the angle of these surfaces, the clearance
between the peripheral wall 32 of the lower frame 12 and the
peripheral wall 50 of the upper frame 10 may be adjusted, thereby
adjusting the maximum tilt angle of the upper frame 10 with respect
to the lower frame 12. Further, the diameter of the sleeve 14 may
be increased or decreased accordingly to account for any increase
or decrease in range of motion while still shielding the upper
frame 10 and the lower frame 12 from the surrounding structure.
[0028] In addition to being capable of tilting, the upper frame 10
may displace vertically with respect to the upper surface of the
lower frame 12. For example, as shown in the illustrated embodiment
of FIG. 4, the upper frame 10 may displace vertically between a
fully extended position and a fully contracted position. The fully
extended position may be the maximum vertical displacement of the
upper frame 10 at which the upper frame 10, lower frame 12 and
sleeve 14 appreciably prevent debris or the surrounding structure
from entering the access opening 15 through the junction between
the upper frame 10 and the lower frame 12. The fully contracted
position may be the minimum vertical displacement allowed by the
surfaces of the upper frame 10 and lower frame 12, which may
contact each other to further contraction. For example, the upper
surface 40 of the lower frame 12 may contact the flange 56 at a
point of minimum vertical displacement. In addition to or
alternatively, a lower surface of the peripheral wall 50 of the
upper frame 10 may contact the base 34 preventing further
contraction. In the illustrated embodiment, the upper frame 10 is
capable of moving over a range of 4 inches, or between 15.5 inches
and 11.5 inches as measured from the bottom to the top of the frame
assembly 8. In alternative embodiments, depending on the desired
configuration, the frame assembly 8 may be adjusted to increase or
decrease the range of movement, the upper limit, the lower limit,
or a combination thereof.
[0029] By enabling the upper frame 10 to both tilt and displace
vertically, the frame assembly 8 may enable the upper frame 10 to
move or float along with the surrounding structure, an effect that
is sometimes referred to as self-leveling. Self-leveling of the
frame assembly 8 may mitigate against abrupt transitions between
the surface of the surrounding structure and the frame assembly 8.
This self-leveling capability may be maintained through the use of
a sleeve 14 around periphery portions of the upper frame 10 and the
lower frame 12.
[0030] The sleeve 14, shown in the illustrated embodiments of FIG.
2-6, may shield the upper frame 10 and the lower frame 12 from the
surrounding structure while enabling the upper frame 10 to float.
The sleeve 14 may form a rigid structure disposed around portions
of the upper frame 10 and lower frame 12, and in particular, may
prevent the surrounding structure from binding overlapping portions
of the upper frame 10 and the lower frame 12. For example, the
sleeve 14 may create a buffer zone or a gap between the surrounding
structure and the lower frame 12. The upper frame 10 may move
unimpeded, by the surrounding structure, within this buffer zone.
It should be understood that portions of the peripheral wall 50 of
the upper frame 10 may be in contact or adjacent to the surrounding
structure outside of the buffer zone, but within the buffer zone,
the sleeve 14 may substantially prevent the surrounding structure
from contacting and impeding movement of the upper frame 10. The
sleeve 14 may also prevent the surrounding structure or debris from
entering the gap or the buffer zone between the sleeve 14 and the
peripheral wall 32 of the lower frame 12, thereby potentially
preventing the upper frame 10 from being blocked or binding on the
surrounding structure or environment.
[0031] As shown in the illustrated embodiment of FIGS. 5-6, the
sleeve 14 is a rigid material, formed of hot rolled steel. The ends
of the sleeve 14 are overlapped and welded together at the junction
point 64 in order to form an annular structure capable of
surrounding portions of the upper frame 10 and lower frame 12. The
sleeve 14 in some embodiments may be coated to prevent it from
oxidizing and deteriorating. It should also be understood, as
mentioned above, that materials other than steel may be used to
construct the sleeve 14, including for example plastic. And
although described as rigid, the sleeve 14 may be flexible in
alternative embodiments. The sleeve 14 may be constructed of any
material, with varying degrees of plasticity and elasticity,
capable of preventing the surrounding structure from binding the
upper frame 10 or capable of enabling the upper frame 10 to float
with respect to the lower frame 12.
[0032] Directional terms, such as "vertical," "horizontal," "top,"
"bottom," "upper," "lower," "inner," "inwardly," "outer" and
"outwardly," are used to assist in describing the invention based
on the orientation of the embodiments shown in the illustrations.
The use of directional terms should not be interpreted to limit the
invention to any specific orientation(s).
[0033] The above description is that of 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. This disclosure is presented for illustrative
purposes and should not be interpreted as an exhaustive description
of all embodiments of the invention or to limit the scope of the
claims to the specific elements illustrated or described in
connection with these embodiments. For example, and without
limitation, any individual element(s) of the described invention
may be replaced by alternative elements that provide substantially
similar functionality or otherwise provide adequate operation. This
includes, for example, presently known alternative elements, such
as those that might be currently known to one skilled in the art,
and alternative elements that may be developed in the future, such
as those that one skilled in the art might, upon development,
recognize as an alternative. Further, the disclosed embodiments
include a plurality of features that are described in concert and
that might cooperatively provide a collection of benefits. The
present invention is not limited to only those embodiments that
include all of these features or that provide all of the stated
benefits, except to the extent otherwise expressly set forth in the
issued claims. 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.
* * * * *