U.S. patent application number 15/004665 was filed with the patent office on 2016-07-28 for chassis structure for portable electronic devices.
The applicant listed for this patent is LENOVO (SINGAPORE) PTE. LTD.. Invention is credited to Fumitake Mizoguchi, Ryota Nohara, Ryo Otsuka, Takehito Yamauchi.
Application Number | 20160216730 15/004665 |
Document ID | / |
Family ID | 56434077 |
Filed Date | 2016-07-28 |
United States Patent
Application |
20160216730 |
Kind Code |
A1 |
Mizoguchi; Fumitake ; et
al. |
July 28, 2016 |
CHASSIS STRUCTURE FOR PORTABLE ELECTRONIC DEVICES
Abstract
A chassis structure is disclosed. A chassis includes a
plate-like body in which a foam layer is located between a pair of
fiber-reinforced resin plates, and a frame body formed of a
thermoplastic resin and joined to a peripheral portion of the
plate-like body. The plate-like body is configured such that its
peripheral portion is formed by an ear-like joint portion where the
pair of fiber-reinforced resin plates are joined together without
the foam layer located therebetween, thereby sealing the foam layer
inside the pair of fiber-reinforced resin plates. The frame body is
joined to the plate-like body in a state where the frame body is in
contact with the joint portion.
Inventors: |
Mizoguchi; Fumitake;
(Kanagawa-ken, JP) ; Nohara; Ryota; (Kanagawa-ken,
JP) ; Yamauchi; Takehito; (Kanagawa-ken, JP) ;
Otsuka; Ryo; (Kanagawa-ken, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
LENOVO (SINGAPORE) PTE. LTD. |
SINGAPORE |
|
SG |
|
|
Family ID: |
56434077 |
Appl. No.: |
15/004665 |
Filed: |
January 22, 2016 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
G06F 1/1616 20130101;
G06F 1/1637 20130101; G06F 1/1656 20130101; G02F 1/133308
20130101 |
International
Class: |
G06F 1/16 20060101
G06F001/16 |
Foreign Application Data
Date |
Code |
Application Number |
Jan 23, 2015 |
JP |
2015-011390 |
Claims
1. A chassis comprising: a plate-like body having a foam layer
located between a pair of fiber-reinforced resin plates; and a
frame body formed of a thermoplastic resin and joined to a
peripheral portion of said plate-like body, wherein said plate-like
body is configured such that said peripheral portion of said
plate-like body is formed by an ear-like joint portion where said
pair of fiber-reinforced resin plates are joined together without
said foam layer located therebetween, thereby sealing said foam
layer inside said pair of fiber-reinforced resin plates, wherein
said frame body is joined to said plate-like body in a state where
said frame body is in contact with said joint portion.
2. The chassis of claim 1, wherein said joint portion has a flat
plate portion along an outer surface of said chassis; and said
frame body is joined to an inner surface of said flat plate
portion.
3. The chassis of claim 2, wherein said flat plate portion extends
to an edge of at least a part of said chassis.
4. The chassis of claim 3, wherein said joint portion has a bent
portion formed by bending said flat plate portion at said edge of
said chassis, wherein said frame body is joined to an inner surface
of said bent portion.
5. The chassis of claim L, wherein each fiber-reinforced resin
plate contains a carbon fiber.
6. The chassis of claim 1, wherein said foam layer has a planar
shape whose external shape is smaller than each fiber-reinforced
resin plate, and is disposed inward of peripheral portions of said
pair of fiber-reinforced resin plates.
7. The chassis of claim 1, wherein said frame body is joined to
said plate-like body by injection-molding said thermoplastic
resin.
8. A portable electronic device comprising: a body having a
keyboard; and a lid containing a display, wherein said lid includes
a plate-like body having a foam layer located between a pair of
fiber-reinforced resin plates; and a frame body formed of a
thermoplastic resin and joined to a peripheral portion of said
plate-like body, wherein said plate-like body is configured such
that said peripheral portion of said plate-like body is formed by
an ear-like joint portion where said pair of fiber-reinforced resin
plates are joined together without said foam layer located
therebetween, thereby sealing said foam layer inside said pair of
fiber-reinforced resin plates, wherein said frame body is joined to
said plate-like body m a state where said frame body is in contact
with said joint portion.
Description
PRIORITY CLAIM
[0001] The present application claims benefit of priority under 35
U.S.C. .sctn.120, 365 to the previously filed Japanese Patent
Application No JP2015-011390 with a priority date of Jan. 23, 2015,
which is incorporated by reference herein.
BACKGROUND OF THE INVENTION
[0002] 1. Technical Field The present invention relates to
electronic devices in general, and particularly to a structure that
can be applied to a chassis of an electronic device.
[0003] 2. Description of Related Art
[0004] Chassis of various electronic devices, such as laptop
personal computers (laptop PCs), tablet personal computers (tablet
PCs), mobile phones, etc., should be thin, light, and strong. In
view of this, a plate-like chassis material in which a foam layer
is "sandwiched" between prepreg plates (fiber-reinforced resin
plates) having reinforcing fibers such as carbon fibers impregnated
with a thermosetting resin such as an epoxy resin is widely used
for the chassis of electronic devices.
[0005] According to the prior art, an anchor effect is generated by
injection-molding the thermoplastic resin on the end face of the
plate-like body to cause the thermoplastic resin to enter the foam
layer sandwiched between the fiber-reinforced resin plates so that
high joining strength can be obtained. However, with this
structure, it is difficult to control the amount of the
thermoplastic resin entering the foam layer, which complicates the
manufacturing management process.
[0006] Consequently, it would be desirable to provide an improved
chassis structure that allows for a simpler manufacturing
management process.
SUMMARY OF THE INVENTION
[0007] In accordance with a preferred embodiment of the present
invention, a chassis structure includes a plate-like body in which
a foam layer is located between a pair of fiber-reinforced resin
plates, and a frame body formed of a thermoplastic resin and is
joined to a peripheral portion of the plate-like body. The
plate-like body is configured such that the peripheral portion of
the plate-like body is formed by an ear-like joint portion where
the pair of fiber-reinforced resin plates are joined together
without the foam layer located therebetween, thereby sealing the
foam layer inside the pair of fiber-reinforced resin plates. The
frame body is joined to the plate-like body in a state where the
frame body is in contact with the joint portion.
[0008] With this configuration, since the foam layer is sealed
between the pair of fiber-reinforced resin plates, the
thermoplastic resin forming the frame body does not enter the foam
layer when the frame body is being joined to the plate-like body.
As a result, the manufacturing process of the chassis is much
simpler, and the manufacturing cost can also be reduced. Further,
since the plate-like body and the frame body are joined together by
contacting the frame body with the joint portion provided in the
peripheral portion of the plate-like body, the contact area between
the plate-like body and the frame body can be sufficiently ensured
so that high joining strength can be obtained therebetween.
[0009] The flat plate portion may extend to an edge of at least a
part of the chassis material. Accordingly, high strength can be
ensured over the entire external shape of the chassis material, and
since a seam between the fiber-reinforced resin plates and the
frame body does not appear on the outer surface, the external
appearance quality becomes even higher. As a result, it is possible
to reduce or eliminate a post-treatment step, such as a surface
treatment, for covering the seam.
[0010] The joint portion may have a bent portion formed by bending
the flat plate portion at the edge of the chassis material and the
frame body may be joined to an inner surface of the bent portion.
Accordingly, since the outer surface of the chassis and an outer
surface of a side surface of the chassis can be integrally formed
by the fiber-reinforced resin plates, it is possible to achieve
even higher strength.
[0011] All features and advantages of the present disclosure will
become apparent in the following detailed written description.
BRIEF DESCRIPTION OF THE DRAWINGS
[0012] The disclosure itself, as well as a preferred mode of use,
further objects, and advantages thereof, will best be understood by
reference to the following detailed description of an illustrative
embodiment when read in conjunction with the accompanying drawings,
wherein.
[0013] FIG. 1 is a perspective view of an electronic device having
a chassis formed of a chassis structure according to a preferred
embodiment of the present invention;
[0014] FIG. 2 is a plan view of a back cover of the lid of the
electronic device from FIG. 1;
[0015] FIG. 3 is a cross-sectional view taken along line III-Ill of
FIG. 2;
[0016] FIG. 4 is a cross-sectional view taken along line IV-IV of
FIG. 2;
[0017] FIG. 5 is a cross-sectional view showing a peripheral
portion according to a modification of a peripheral portion shown
in FIG. 3;
[0018] FIG. 6 is a cross-sectional view showing a peripheral
portion according to a modification of a peripheral portion shown
in FIG. 4,
[0019] FIG. 7 is a cross-sectional view for explaining a method of
manufacturing the chassis structure according to a preferred
embodiment of the present invention; and
[0020] FIG. 8 is a perspective view showing the chassis structure
used as a back cover of a tablet PC.
DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT
[0021] Referring now to the drawings and in particular to FIG. 1,
there is depicted a perspective view of an electronic device 16
having a lid 14 constituted by an electronic device chassis 12
formed of a chassis material 10, according to a preferred
embodiment of the present invention. In this embodiment, there is
shown by way of example a configuration in which the electronic
device chassis 12 formed of the chassis material 10 is applied to
the lid 14 of the electronic device 16 as a laptop PC. As shown,
the electronic device 16 includes a device body 20 having a
keyboard device 18, and the rectangular flat plate-like lid 14
having a display device 22 composed of a liquid crystal display and
so on, and is of the clamshell type in which the lid 14 is coupled
to the device body 20 via left and right hinges 24 so as to be
openable and closable. Various electronic components, not
illustrated, such as a board, an arithmetic processing unit, a hard
disk device, and a memory, are housed in the device body 20.
[0022] The lid 14 includes the electronic device chassis 12 having
a back cover 12a and a front cover 12b. The back cover 12a is a
cover member covering side surfaces and a back surface of the lid
14 and is formed of the chassis material 10 according to this
embodiment. The front cover 12b is a resin cover member covering a
front surface of the lid 14 jointly with the display device 22. A
pair of left and right antennas 26, 26 are provided in the
electronic device chassis 12 near its upper end portion. The
antennas 26, 26 are used for transmission and reception of radio
waves that are used in wireless communications and so on.
[0023] Next, the configuration of the back cover 12a of the lid 14
and the chassis material 10 forming the back cover 12a will be
described in detail.
[0024] The overall configuration of the back cover 12a will be
described. FIG. 2 is a plan view showing the configuration of the
back cover 12a of the lid 14 and showing the inner side of the back
cover 12a where the display device 22 is received.
[0025] As described above, the back cover 12a is formed of the
chassis material 10. As shown in FIG. 2, the back cover 12a is a
panel-like cover member in which a wall portion 28 is formed
upright on the periphery thereof to serve as side surfaces of the
electronic device chassis 12 along its four sides.
[0026] The antennas 26 are provided on an inner surface of the back
cover 12a at its upper edge portion. A pair of recesses 29 in which
the hinges 24 are respectively disposed are cutout-formed at a
lower edge portion of the back cover 12a.
[0027] Next, a specific configuration of the chassis material 10
forming the back cover 12a will be described. FIG. 3 is a
cross-sectional view taken along line 111-Ill of FIG. 2 and FIG. 4
is a cross-sectional view taken along line IV-IV of FIG. 2.
[0028] As shown in FIGS. 2 to 4, the chassis material 10 includes a
plate-like body 34 of a stacked structure in which a foam layer 32
is sandwiched between a pair of upper and lower fiber-reinforced
resin plates (prepreg layers) 30 and a frame body 36 joined to
peripheral portions 40, 41 of the plate-like body 34.
[0029] Each fiber-reinforced resin plate 30 is a prepreg in which
reinforcing fibers are impregnated with a thermosetting resin such
as an epoxy resin. In this embodiment, it is made of a carbon
fiber-reinforced resin (CFRF) using carbon fibers as the
reinforcing fibers. The reinforcing fibers may be other than the
carbon fibers and may be made of any of various materials, for
example, metal fibers such as stainless steel fibers and inorganic
fibers such as glass fibers.
[0030] The foam layer 32 is a soft spacer provided between the pair
of fiber-reinforced resin plates 30 and serving to space these hard
fiber-reinforced resin plates 30 from each other. By providing the
foam layer 32, the section modules of the plate-like body 34 in its
thickness direction increases to create a light and strong
structure. The foam layer 32 is formed by, for example, a foam
sheet of polypropylene or the like.
[0031] As shown in FIGS. 3 and 4, the plate-like body 34 has a
structure such that its peripheral portions along its four sides
are formed by an ear-like joint portion 38 where the pair of
fiber-reinforced resin plates 30 are joined together without
sandwiching the foam layer 32 therebetween, thereby sealing the
foam layer 32 inside the pair of fiber-reinforced resin plates 30.
The joint portion 38 is obtained by joining the fiber-reinforced
resin plates 30 together by pressing when forming the plate-like
body 34. The plate-like body 34 may have a stacked structure of
five or more layers in which foam layers 32 are respectively
sandwiched between adjacent two of three or more fiber-reinforced
resin plates 30. In this case, the joint portion 38 is formed by
joining the three or more fiber-reinforced resin plates 30
together.
[0032] The peripheral portions along the four sides of the
plate-like body 34 of this embodiment differ in structure between
the upper edge portion (upper side), where the antennas 26 are
disposed, of the back cover 12a and the other left and right side
edge portions (left and right sides) and lower edge portion (lower
side) of the back cover 12a.
[0033] As shown in FIG. 3 (see also FIG. 2), in the peripheral
portion 40 along the left side, the right side, and the lower side
other than the upper side where the antennas 26 are disposed, the
joint portion 38 has a flat plate portion 38a flush with and
extending along an outer surface 42 of the chassis material 10
(back cover 12a) and a bent portion 38b formed by bending the flat
plate portion 38a perpendicularly inward of the back cover 12a at
the edge. The length of the flat plate portion 38a may be set to
substantially zero and the bent portion 38b may be formed by
bending the joint portion 38 near the boundary with the foam layer
32. The fiber-reinforced resin plate 30 on the inner side (lower
side in FIG. 3) of the plate-like body 34 is formed, near the joint
portion 38, with an inclined surface 30a inclined toward the
outer-side fiber-reinforced resin plate 30.
[0034] The frame body 36 is joined to the plate-like body 34 by
injection-molding a thermoplastic resin on inner surfaces of the
flat plate portion 38a the bent portion 38b, and the inclined
surface 30a. The frame body 36 is a frame-like portion where
non-illustrated screw holes, rib shapes, and so on for attaching
the front cover 12b are formed. As the thermoplastic resin forming
the frame body 36, it is preferable to use, for example, a
polyethylene resin or a polypropylene resin, or use may be made of
a fiber-reinforced resin (e.g., GFRP) in which such a resin
contains reinforcing fibers such as glass fibers. In this
embodiment, the frame body 36 is formed of a non-conductive
material.
[0035] Accordingly, in the peripheral portion 40 shown in FIG. 3,
the flat plate portion 38a of the joint portion 38 where the
fiber-reinforced resin plates 30, 30 are joined together extends to
the outer edge of the chassis material 10 and the frame body 36 is
joined to the inner side thereof. Further, the outer surface of the
wall portion 28 of the peripheral portion 40 is mostly formed by
the bent portion 38b of the joint portion 38 and the frame body 36
is joined to the inner side thereof.
[0036] Consequently, in the peripheral portion 40, the joining area
(contact area) between the fiber-reinforced resin plates 30 and the
frame body 36 can be sufficiently ensured by the joint portion 38,
and therefore, the plate-like body 34 and the frame body 36 can be
joined together with high joining strength. Further, since the
outer surface 42 of the chassis material 10 is formed to reach the
edge by the high-strength fiber-reinforced resin plates 30 and the
lower-strength frame body 36 is joined to the inner side thereof,
it is possible to ensure the strength of the entire peripheral
portion 40. Further, since a seam between the fiber-reinforced
resin plates 30 and the frame body 36 does not appear on the outer
surface 42, the external appearance quality is high, and since a
post-treatment such as a surface treatment for covering the seam is
not required, the manufacturing cost can be reduced.
[0037] Next, as shown in FIG. 4 (also in FIG. 2), in the peripheral
portion 41 along the upper side where the antennas 26 are disposed,
the joint portion 38 has a flat plate portion 38a flush with the
outer surface 42 of the chassis material 10 (back cover 12a) and
extending slightly from an end portion of the foam layer 32 along
the outer surface 42. Therefore, differently from the flat plate
portion 38a of the peripheral portion 40 shown in FIG. 3, the flat
plate portion 38a of the peripheral portion 41 does not reach the
edge of the chassis material 10. Also in the peripheral portion 41,
the fiber-reinforced resin plate 30 on the inner side (lower side
in FIG. 4) of the plate-like body 34 is formed with an inclined
surface 30a.
[0038] The frame body 36 is joined to the plate-like body 34 by
injection-molding the thermoplastic resin on an inner surface and
an end face of the flat plate portion 38a and an inner surface of
the inclined surface 30a. In the case of this configuration, the
frame body 36 is formed so as to be flush with and extend along the
outer surface 42 of the back cover 12a and to protrude inward of
the back cover 12a at the edge.
[0039] Therefore, in the peripheral portion 41 shown in FIG. 4, the
flat plate portion 38a of the joint portion 38 where the
fiber-reinforced resin plates 30 are joined together does not
extend to the edge of the chassis material 10 and the frame body 36
is joined to the inner side and the lateral side thereof. Further,
the wall portion 28 of the peripheral portion 41 is formed by the
frame body 36 and the antennas 26 are provided on the inner side of
the wall portion 28.
[0040] Consequently, in the peripheral portion 41, although smaller
than in the case of the peripheral portion 40, the joining area
(contact area) between the fiber-reinforced resin plates 30 and the
frame body 36 can be sufficiently ensured by the joint portion 38,
and therefore, the plate-like body 34 and the frame body 36 can be
joined together with high joining strength. Further, since the
fiber-reinforced resin plates 30 made of the conductive material
are not disposed on the outer side of the antennas 26 and instead
the frame body 36 made of the non-conductive material is disposed,
high sensitivity of the antennas 26 is ensured. In the case where
the antennas 26 are not required to be disposed due to a
specification of the electronic device 16 or the like, the
peripheral portion 41 may have the same structure as the peripheral
portion 40 shown in FIG. 3.
[0041] The shapes of the peripheral portions 40, 41 may of course
be other than those shown in FIGS. 3 and 4. For example, the
peripheral portion 40 may be a peripheral portion 40A having a
shape with the bent portion 38b omitted as shown in FIG. 5. In the
peripheral portion 40A, a flat plate portion 38a of a joint portion
38 extends to the edge of a chassis material 10 and a frame body 36
is joined to the inner side of the flat plate portion 38a.
[0042] For example, the peripheral portion 41 may be a peripheral
portion 41A in which a flat plate portion 38a of a joint portion 38
is formed stepped from an outer surface 42 of a chassis material 10
as shown in FIG. 6. In the peripheral portion 41A, compared to the
peripheral portion 41 shown in FIG. 4, a frame body 36 is joined
also to the outer side of the flat plate portion 38a in addition to
the inner side and the lateral side thereof and therefore the
joining strength of the frame body 36 to the plate-like body 34
becomes even higher.
[0043] FIG. 7 is a cross-sectional view for explaining a method of
manufacturing the chassis material 10, according to a preferred
embodiment of the present invention. When manufacturing the chassis
material 10, first, a pair of planar fiber-reinforced resin plates
30, each having a predetermined external shape (e.g., a rectangular
shape) are prepared, then a planar foam layer 32 (e.g., a foam
sheet) having a predetermined external shape (e.g., a rectangular
shape) smaller than each of the fiber-reinforced resin plates 30 is
sandwiched therebetween, and then the three layers (i.e., two resin
plates 30 and one foam layer 32) are pressed in a stacking
direction thereof. In this event, a plate-like body 34 of a
sandwich structure is formed in which the foam layer 32 is sealed
inside by an ear-like joint portion 38 that is formed in peripheral
portions 40, 41 by pressing together the pair of fiber-reinforced
resin plates 30 at portions where the foam layer 32 is not
sandwiched therebetween.
[0044] Subsequently, as shown in FIG. 7, the plate-like body 34 is
set in a mold 44 and then a molten thermoplastic resin is injected
into a cavity 46 through an injection port 44a, thereby
injection-molding the thermoplastic resin so as to be in contact
with the joint portion 38 of the plate-like body 34. Although FIG.
7 shows by way of example a method of manufacturing the peripheral
portion 40 shown in FIG. 3, this can also be applied, almost as it
is, to a method of manufacturing the peripheral portion 41 shown in
FIG. 4. As a result, as shown in FIGS. 3 and 4, a frame body 36 is
formed at the peripheral portions 40, 41 of the plate-like body 34
so that the chassis material 10 is formed.
[0045] As described above, in the chassis material 10 according to
the present to embodiment, the plate-like body 34 is configured
such that its peripheral portions 40 (40A), 41 (41A) are formed by
the ear-like joint portion 38 where the pair of fiber-reinforced
resin plates 30, 30 are joined together without sandwiching the
foam layer 32 therebetween, thereby sealing the foam layer 32
inside (at a central portion of) the pair of fiber-reinforced resin
plates 30, 30, while the frame body 36 is joined to the plate-like
body 34 in the state where the frame body 36 is in contact with the
joint portion 38.
[0046] Accordingly, since the foam layer 32 is sealed between the
fiber-reinforced resin plates 30, the thermoplastic resin forming
the frame body 36 does not enter the foam layer 32 when joining the
frame body 36 to the plate-like body 34, and therefore, the
manufacturing management thereof is easy and thus the manufacturing
cost thereof can be reduced. Further, since the plate-like body 34
and the frame body 36 are joined together by contacting the frame
body 36 with the joint portion 38 provided in the peripheral
portions 40, 41 of the plate-like body 34, the contact area between
the plate-like body 34 and the frame body 36 can be sufficiently
ensured to obtain high joining strength therebetween so that the
strength of the chassis material 10 also becomes high.
[0047] The joint portion 38 has the flat plate portion 38a
extending along the outer surface 42 of the chassis material 10 and
the frame body 36 is joined to the inner surface of the flat plate
portion 38a (see FIGS. 3 to 6). Accordingly, the outer surface 42
of the chassis material 10 is formed to be planar by the flat plate
portion 38a (and the frame body 36) so that the external appearance
quality is high. Herein, in the peripheral portions 40, 40A shown
in FIGS. 3 and 5, the flat plate portion 38a extends to the edge of
the chassis material 10. Therefore, high strength can be ensured
over the entire external shape of the chassis material 10 and,
further, since a seam between the fiber-reinforced resin plates 30,
30 and the frame body 36 does not appear on the outer surface 42,
the external appearance quality becomes even higher and it is
possible to reduce or eliminate a post-treatment such as a surface
treatment for covering the seam.
[0048] In this case, in the peripheral portion 40 shown in FIG. 3,
the joint portion 38 has the bent portion 38b formed by bending the
flat plate portion 38a at the edge and the frame body 36 is joined
also to the inner surface of the bent portion 38b, In other words,
according to the chassis material 10, by providing the joint
portion 38 having no foam layer 32 in the peripheral portion 40 of
the plate-like body 34, it is possible to draw the joint portion 38
to form the bent portion 38b without being hindered by the foam
layer 32. Consequently, since the outer surface 42 of the chassis
material 10 and the outer surface of the wall portion 28 serving as
the side surface of the chassis material 10 can be integrally
formed by the fiber-reinforced resin plates 30, it is possible to
achieve even higher strength and to further reduce a post-treatment
such as a surface treatment.
[0049] As has been described, the present disclosure provides an
improved chassis structure that allows for a simpler manufacturing
management process.
[0050] The present invention is not limited to the above-described
embodiment and changes can of course be made freely within a range
not departing from the gist of the present invention. For example,
in the above-described embodiment, there is shown by way of example
the configuration in which the chassis material 10 is used as the
electronic device chassis 12 of the lid 14 forming the electronic
device 16, but the chassis material 10 may be used for the device
body 20.
[0051] Further, the chassis material 10 can be used as a chassis
material of various electronic devices such as a tablet PC, a
desktop PC, a smartphone, and a cellular phone, other than the
laptop PC. For example, as shown in FIG. 8, in the case of an
electronic device 50 as a tablet PC, since it has a touch-operable
display device 52 at the front of an electronic device chassis 54,
a rectangular flat plate-like back cover (back plate) 54a is
preferably formed of a chassis material 10. In this event,
preferably, the upper side, where an antenna 26 is provided, of the
electronic device chassis 54 has the same structure as the
peripheral portion 41 shown in FIG. 4, while the other three sides
of the electronic device chassis 54 have the same structure as the
peripheral portion 40 shown in FIG. 3.
[0052] While the disclosure has been particularly shown and
described with reference to a preferred embodiment, it will be
understood by those skilled in the art that various changes in form
and detail may be made therein without departing from the spirit
and scope of the disclosure.
* * * * *