Note: Descriptions are shown in the official language in which they were submitted.
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Description
FASTENER WITH PLANULAR COIL
Field of Invention
This invention relates generally to a fastener releasably securable to a
target member,
and more particularly to a screw releasably securable to a thermoplastic
member.
Background Art
Screws releasably securable to wooden, stone, or metal target members are well
known. In their conventional embodiment, said screws generally comprise a
shaft, turning
means disposed at one end of said shaft, and thread co-axially disposed on
said shaft.
However, said conventional screws cannot be adequately secured in a releasable
fashion to certain target members having a particular shape, orientation or
composition.
Consequently, specialized attaching structures have been developed and made
known.
For example, U.S. Patent No. 4,463,753 discloses a compression bone screw for
repairing a fibular bone fracture having a shaft, tool interengaging means at
one end of said
shaft, distal thread disposed at the distal portion of said shaft,
intermediate portion of said
shaft having a substantially smooth surface, and proximal thread disposed at
the proximal
portion of said shaft.
U.S. Patent No. 4,403,895 provides for a retainer for securing a floor mat to
the
carpet layer and padding layer, if any, installed on the floor of a vehicle.
Said retainer
includes a tapered shank having a self-piercing point at its lower end;
external spiral high
lead disposed along said shank; partial shoulder adjacent to the lower end of
said shank; and
full shoulder adjacent the upper end of said shank. Since the distance between
said partial
shoulder and said full shoulder is less than the thickness of said carpet
layer, said carpet
layer is compressed between said partial shoulder and said full shoulder to
create a
demountable attachment between said carpet layer and said retainer when said
retainer is
rotated into said carpet layer.
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Said conventional screws are not an effective means for creating a releasable
attachment with a target member comprised of a soft buoyant resilient material
such as a
thermoplastic foam because of the relatively low structural integrity of soft
buoyant resilient
materials such as thermoplastic foam. Consequently, there is a need for a
fastener having
a construction that is particularly applied to create a releasable attachment
with a target
member comprising a soft buoyant resilient material such as a thermoplastic
foam.
Disclosure of Invention
In accordance with one aspect of the invention, there is provided a fastener
releasably
securable to a target member comprising a shaft, means for turning said shaft
presented at
one end of said shaft, and planular helical coil disposed along said shaft.
In accordance with another aspect of the present invention, there is provided
a screw
releasably securable to a thermoplastic member comprising a shaft rotatable
about an axis of
rotation, head which includes a turning means at one end of said shaft, and
planular helical
coil co-axially mounted on said shaft.
In accordance with still another aspect of the invention, there is provided a
screw
releasably securable to a thermoplastic member comprising a rotatable shaft;
head disposed
at one end of said shaft which includes a turning means for turning said shaft
in a first
direction to secure said screw in to said thermoplastic member and for turning
said shaft in
a second direction to release said shaft from said thermoplastic member; said
shaft including
a locking ridge to inhibit rotation of said screw in said second direction
when said
thermoplastic member is engaged by said screw; and at least one planular
helical coil
disposed on said shaft which includes a rounded helical edge to minimize
destructure of said
thermoplastic member; and locking means comprising a straight radial edge
disposed on said
planular helical coil which further impedes rotation of said screw in said
second direction.
In accordance with a further aspect of the invention, a screw releasably
securable to
a thermoplastic member comprising a shaft rotatable about an axis of rotation,
means for
turning said shaft at one end of said shaft, surface disposed outwardly from
said shaft to
define a helical edge for insertion into said thermoplastic member, and
wherein said surface
resists axial withdrawal of said screw from said thermoplastic member.
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Brief Description of Drawings
Fig. 1 is a side view of the first preferred embodiment of the fastener;
Fig. 2 is a side view of the first preferred embodiment of the fastener at a
45-degree
angle;
Fig. 3 is a side view of the second preferred embodiment of the fastener.
Fig. 4 is a cross-sectional view of the planular helical coil of said fastener
at a point
of the shaft adjacent to the lower extremity of said planular helical coil.
Fig. 5 is a partial side view of the fastener in which the turning means has
wings.
Fig. 6 is a top view of the turning means of the fastener showing variations
of the
turning socket thereof.
Fig. 7 is a partial side view of the fastener in which the bottom of the
turning means
includes a plurality of spikes for biting into the surface of the target
member.
Best Mode for Carrying Out the Invention
In the description which follows, like parts are marked throughout the
specification
and the drawings with the same respective reference numerals. The drawings are
not
necessarily to scale and in some instances proportions may have been
exaggerated in order
to more clearly depict certain features of the invention.
Referring to Fig. 1 there is illustrated in a side view, a fastener 10 in
accordance with
the first preferred embodiment of the present invention. Said fastener 10
includes a shaft 12,
turning means 14 presented at one end of said shaft 12 adjacent to the top of
said shaft 12
for turning said shaft, planular helical coil 16 disposed along said shaft,
and shaft end 18
presented at another end of said shaft 12. Said shaft end 18 can be pointed,
as in the case
of the first preferred embodiment of the fastener shown in Fig. 1, or rounded
or straight, as
the case may be.
When said shaft end 18 is brought into contact with a target member 15
comprising
a soft buoyant resilient material such as a thermoplastic foam, if said
fastener 10 is turned
in a first direction, the same is rotated into said target member 15. When
said fastener is
turned in a second direction, said fastener is rotated out of said target
member 15.
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As best shown in Fig. 2, said planular helical coil 16 includes a cutting edge
20
disposed at the distal end 21 of said planular helical coil 16 for cutting
into the target
member 15 comprised of a soft buoyant resilient material such as a
thermoplastic foam.
When said fastener 10 is brought into contact with said target member 15
comprising a soft
buoyant resilient material such as a thermoplastic foam and turned in said
first direction, said
cutting edge 20 cuts in to said target member 15, consequently, said fastener
10 can be
rotated into said target member comprising a soft buoyant resilient material
such as a
thermoplastic foam.
As shown in Fig. 2, said planular helical coil 16 further includes a locking
means 22
consisting of a straight radial edge disposed at the proximal end 23 of said
planular helical
coil 16. Said locking means 22 inhibits the turning of said fastener 10 in
said second
direction once said fastener 10 has been rotated into said target member 15
because the soft
buoyant resilient material, such as a thermoplastic foam, comprising said
target member 15
decompresses adjacent to said locking means 22 so as to present a blocking
mass impeding
rotation of said fastener 10 in said second direction.
As best shown in Fig. 1, said planular helical coil 16 also includes a rounded
helical
edge 24 for biting into said target member 15 when said fastener 10 is rotated
into said target
member 15 to minimize destructure of said target member.
Said shaft 12 can be smooth, as shown in Figs. 1 and 2, or threaded as shown
in Fig.
3. In addition, as best shown in Fig. 4 which shows a cross-sectional view of
said fastener,
said shaft 12 can be fashioned to include a locking ridge 26 which further
impedes rotation
of said fastener in said second direction.
As shown in Fig. 5, said turning means 14 can be adapted to include wings 27
to
facilitate manual rotation of said fastener 10 without the use of a tool such
as a screw driver
for rotating said fastener 10. In addition, as shown in Fig. 6, said turning
means 14 can be
modified to include various forms of sockets. Lastly, said turning means 14
can be further
adapted to include a means for biting into the surface of said target member
when said
fastener is rotated into said target member, such as a plurality of spikes 28
shown in Fig. 7
which extend downwardly from the bottom of said turning means 14 and are
spaced apart
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from said shaft 12. Said spikes 28 engage the surface of said target member
when said
fastener is fully rotated into said target member so as to further secure the
attachment of said
fastener to said target member.
Both the first and second preferred embodiment of the present invention shown
in
Figs. 1, 2, and 3 include one planular helical coil disposed adjacent to the
distal end 11 of
said shaft 12. However, other embodiments of the fastener are contemplated in
which said
planular helical coil is disposed at an intermediate position along said shaft
12, for example,
adjacent to the proximal end 13 of said shaft 12. The invention disclosed
herein is also
adaptable to include more than one planular helical coil disposed along said
shaft 12, for
example, one planular helical coil at said distal end 11 end of said shaft and
another planular
helical coil at the proximal end 13 of said shaft.
Various embodiments of the invention have now been described in detail. Since
changes in and/or additions to the above-described best mode may be made
without departing
from the nature, spirit or scope of the invention, the invention is not to be
limited to said
details.
