Note: Descriptions are shown in the official language in which they were submitted.
CA 02484135 2004-10-07
LOCKING CLIP
BACKGROUND OF THE INVENTION
a. Field of the Invention
The present invention relates generally to clips and similar gripping devices
and,
more particularly, to a locking clip that grips sheets of cloth, plastic or
other material
b. Background Art
Numerous clips and other gripping devices have been proposed for gripping or
cloth, plastic or other sheet-type materials. Some common examples include
suspender
clips for gripping pants, clothespins for securing clothing t~o the drying
line, and binder
clips for binding stacks of paper. Adaptations on clips of this nature have
been used as an
improvised means of securing canvas tarps or plastic sheets in an attempt to
protect articles
from environmental conditions, and certain gripping devices have evolved
specifically for
this type of application.
Tarps and other sheet coverings of course have a multitude of uses. For
example,
boaters commonly protect the deck and cockpits of their craft using canvas
coverings.
Normally such protective coverings are fitted with grommets and secured with
rope.
However, with age and weathering, the grommets often fail or the canvas
deteriorates and
supplemental means are required to secure the existing cover. As an
inexpensive
alternative to a new cover, a plastic tarp may be substituted. In either case,
an alternative
means for securing the cover is required.
During camping excursions it is common to see makeshift shelters erected from
plastic tarps to protect the campsite occupants and gear from sun and rain.
The tarps are
often secured to trees via cord attached to corner grommets. However, the
grommets are
often inadequate in terms of number, spacing, or strength to provide the
necessary support.
CA 02484135 2004-10-07
2
As a result, the shelters typically fail due to wind loads or rain
accumulation. Additional
means for securing these types of temporary tarp shelters would be beneficial.
Tarps or other protective coverings are also commonly used to shelter goods
during
road transport by pickup trucks and automobiles with trailers 'in tow. ~ften
times the tarps
have no convenient means for securing them to the vehicle, and, as a result,
they noisily
flap in the wind and risk being ripped from the vehicle possibly resulting in
a dangerous
traffic situation. Commercial vehicles, such as dump trucks, often. employ
coverings to
prevent construction site dirt and debris from blowing out of the vehicle
during highway
transport, and commercial trucking fleets often use curtain-like coverings on
their trailers
to shelter transported goods. Although sometimes these coverings have
integrated securing
mechanisms, failures in the mechanisms or reconfiguration to accommodate
unanticipated
changes in the load being transported requires a cover securing means that is
easily
adaptable to the new situation.
In many instances sheet material can also be used to provide temporary or semi-
permanent coverings on a much larger scale. For example, large expanses of
plastic
sheeting are often used as temporary cover in the construction and civil
engineering
industries, e.g., to provide cover for a construction area or road
resurfacing/repair. Such
large installations call for an effective, inexpensive and rapidly installed
attachment for
securing the edge of the plastic sheeting material. Moreover, such material
(for example,
VisqueenTM) typically lacks any form of grommets or similar structures that
might be used
as attachment points.
In all of these examples it would therefore be desirable to have an
inexpensive
gripping device that could be quickly and easily attached to the edge of the
tarp or other
covering such that it could be securely affixed by a rope or cord. The prior
devices
developed to accommodate this need are often inconvenient to implement and
limited in
their usage. Furthermore, these devices often fail themselves due to
structural inadequacies
or cause damage to the attached sheet material which subsequently fails; or
they simply do
not supply enough grip pressure to stay connected to the sheet material.
Finally,
considering the number of prier devices that may be required to safely secure
the sheet
material, the expense of such devices is often prohibitive.
CA 02484135 2004-10-07
3
Accordingly, there exists a need for a clip device for engaging and securing
fabric,
cloth, plastic or other sheet material, whether flexible or somewhat rigid,
which is quickly
and easily attached or removed and is easily adaptable to many materials and
situations.
Furthermore, there is a need for such a device that can be attached to a rope
or cord in a
rapid and convenient matter. Still further, there is a need for such a device
that provides
excellent grip and structural strength without compromising the integrity of
the gripped
material. Moreover, there is a need for such a device that is economical to
manufacture.
SLJMMAR~' OF TFIE INVENTION
The present invention has solved the problems cited above, and is a locking
clip
assembly for gripping and securing a tarp or other sheet of material.
In a preferred embodiment, the clip assembly comprises (a) first and second
jaw
members arranged in opposition to one another, each jaw member comprising a
grip
portion for engaging the sheet of material; (b) first and second resilient
lever arm members
extending from the first and second jaw members respectively and crossing one
another at
a common pivot point, the lever arms providing means for resiliently biasing
said jaws into
engagement with leveraged pliers-like force; (c) a hinge mechanism located at
the
intersection where the lever arms cross and providing a common pivot point for
activating
the jaws via the lever arms; and (d) a securement element that concurrently
provides
means for connecting the device to a rope, shock cord, "bungee" cord, or other
attachment
element and which further serves to lock the lever arms in the compressed
position until
the attachment element is removed.
The opposing first and second jaw members may each comprise a generally planar
face to which the grip portion rnay be integrally joined and which defines the
contact area
for engaging the sheet of material. The generally planar facE;s of the
opposing jaws may be
arranged in a manner such that, when the jaws are closed on each other, their
planes
slightly diverge and intersect along an axis parallel with the hinge axis, but
become parallel
when a sheet of material of typical nominal thickness is engaged between them.
The grip
portion on each jaw may comprise a rectangular array of teeth for engaging and
retaining
the sheet material. The array of teeth on the first grip face may be
configured to be
CA 02484135 2004-10-07
4
received in the valleys between the array of teeth on the second grip face,
and vice versa;
and each individual tooth may be raked back towards the hinge point and away
from the
sheet material to provide more tenacious gripping action.
The first lever arm may be a generally rectangular integral extension of the
first jaw
member and as such extends linearly and parallel to the grip face and
substantially through
the hinge point. This first lever arm may comprise an elongated slot (to
accept the second
lever arm) that passes through the lever arm generally normal to the grip face
and extends
from a location adjacent the grip face, substantially beyond the hinge point
to a location
adjacent the terminal end of the arm. The second lever arm may comprise a
generally
rectangular cross-section that extends from the grip face of the second jaw
member at an
obtuse angle, passing through the hinge point and arcing into a plane
generally parallel
with the grip face. The width of this second lever arm, measured parallel to
the hinge axis,
may be substantially narrower than the jaw member from wlhich it extends and
somewhat
narrower than the slot in the first lever arm through which it rnay pass.
The configuration of the lever arms as described allows them to cross through
a
common axis, with the second lever arm passing through the; slot in the first
lever arm. A
hinge may thus be formed by inserting a pin through holes in each arm that
align along this
common axis, and to reinforce the hinge point the cross-section of each arm
may be
enlarged in the area adjacent the pin. By squeezing the lever arms together, a
substantial
pliers-like force can be applied to the grip teeth for securely engaging the
sheet material.
As an ergonomic aid, the second lever arm may be fitted v~rith an array of
ribs, knurls or
other texturing at its outer crest that provide a slip free platform for the
operator's thumb.
The first lever arm may be equipped with a ribbed, knurled or otherwise
textured
depression on it terminal end that faces away from the second lever arm knurls
and provide
a slip free platform for one of the operator's fingers.
The clip assembly may further comprise an interim locking means that preserves
jaw engagement pressure with the sheet material by maintaining some degree of
lever arm
activation force even after the user releases his hand from the lever arms. In
the preferred
embodiment, the securement element comprises a hook integrated into the
terminal end of
the second lever arm. The hook may be a natural extension of this lever arm
and as such
CA 02484135 2004-10-07
5 may arc towards the first lever arm and then wrap partially back on itself
to form a semi-
annular hook which has a concentric axis parallel to the hinge axis and which
opens
generally towards the hinge. The width of the hook, in a direction parallel to
the hinge
axis, may be consistent with the width of the second lever arm from which it
extends, and
the combined length of the second lever arm and hook extension may be such
that they
could pass through the slot in the first lever arm if rotated unrestrained
about the hinge
axis.
With the lever arms in a relaxed, uncompressed state and the opposing jaw
elements in contact with the sheet material to be stripped, the hook of the
securement
element will partially enter the slot of the first lever arm. ~y firmly
depressing the lever
arms, using the knurled thumb and finger platforms, the teeth on the opposing
jaws engage
the sheet material with high pressure. With additional forger pressure the
lever arms may
be resiliently deflected relative to each other such that the inner radius of
the securement
hook passes completely through the slot in the first lever arm and is exposed
on the
opposite side of the first arm. A rope or cord may then be looped on the
exposed hook and
interference of the rope between the hook and slot may prevent the lever arms
from
returning to their relaxed state even when finger pressure is removed. The
material sheet
will remain firmly gripped within the jaw teeth by the elastic lever arm
activation force
stored in the deflected lever arms, and the clip can be secured by fixing the
free end of the
rope to an anchored object. When the rope is removed, the lever arms
elastically recover
and pivot back into their relaxed state allowing the material sheet to be
removed from the
jaws. Operation of this embodiment relies on the relative; compliance of the
two lever
arms, and these two lever arms may be configured, in terms of dimensions and
material
properties, to accommodate this requirement.
To facilitate installation of the clip to the sheet material and securement of
the rope
to the clip, an interim locking feature may be incorporated.. In the preferred
embodiment,
the interim locking element may comprise opposed engaging ratchet lips, or
pawls/detents,
one lip being integrated into the side of the securement hook of the second
lever arm and
the opposing lip being integrated into the edge formed by the slot and outer
face of the first
lever arm. As discussed previously, by depressing the lever arms, the teeth on
the opposing
CA 02484135 2004-10-07
6
jaws engage and the lever arms may be elastically deflected relative to each
other. When
the appropriate clamping pressure has been obtained, the lever arms may be
further
deflected but in lateral relation to each other such that the opposing interim
locking lips
engage each other. By then releasing finger pressure, the lips remain engaged
by the elastic
recovery force locked in the deflected lever arms, and the material sheet
remains firmly
gripped within the jaw teeth. The position of the interim locking lips may be
adjusted such
that, when engaged, the securement hook is partially exposed through the slot
in the first
lever arm. The rope or cord may then be conveniently looped on the hook and
secured. If
the rope is removed from the hook, the interim locking lips may still engage
maintaining
jaw pressure on the material sheet until the lip activation motion is
reversed.
The invention, together with further aspects and advantages thereof, may be
further
understood by a reading of the following detailed description with reference
to the
accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is an isometric overview of a locking clip assembly in accordance with
the
present invention;
FIG: 2 is an isometric overview of the locking clip assembly of FIG. 1,
showing this
engaging a sheet of material and secured by a rope.
FIG. 3 is an isometric bottom view of the first gripper arm member of the clip
assembly of FIG. l;
FIG. 4 is an isometric top view of the second gripper arm assembly of FIG. 1;
FIG. 5 is a partial, front elevational view of the locking clip assembly of
FIG. I,
showing the engagement and shape of the gripper teeth from the front of the
assembly;
FIG. 6 is a partial, side elevational view of the locking clip assembly of
FIG. l,
showing the engagement and shape of the raked gripper teeth from the side of
the
assembly;
FIG. 7 is a partial, isometric view of the locking clip assembly of FIG. l,
showing
details of the interim locking mechanism thereof;
CA 02484135 2004-10-07
7
FIG. 8 is a side elevational view of the locking clip assembly of FIG. 1,
showing
the jaws in an open position with a sheet of material inserted between the
jaws;
FIG. 9 is a side elevational view of the locking clip assembly of FIG. l,
showing
the jaws beginning to engage a sheet of material inserted between the jaws;
FIG. 10 is a side elevational view of the locking clip assembly of FIG. 1,
showing
the lever arms with pressure applied such that the jaws fully engage a sheet
of material, the
lever arms deflect, and the interim locking element engages;
FIG. 11 is a side elevational view of the locking clip assembly of FIG. 1,
showing
the lever arms with additional pressure applied such that the jaws fully
engage a sheet of
material, the lever arms fully deflect, and the securement hook is fully
exposed through the
I S slot in the first lever arm;
FIG. 12 is a side elevational view of the locking clip assembly of FIG. l,
showing
this fully installed on a sheet of material and secured to an anchor by a
rope;
FIG. 13 is an isometric bottom view of an additional embodiment of gripper/arm
assembly similar to that in FIG. 1, this having a circular ja',v configuration
and a circular
array of conical teeth;
FIG. 14 is an isometric bottom view of an additional embodiment of gripper/arm
assembly similar to that in FIG. 1, this having a circular jaw configuration
and an
alternating concentric pattern of rubber pads and circular arrays of conical
teeth;
FIG. 15 is an isometric bottom view of an additional embodiment of first
gripper/arm assembly similar to that in FIG. l, this having a rectangular
array of teeth
surrounded by a rubber lip and with the jaw edges radiused;
FIG. 16 is an isometric sectional view of an additional embodiment of locking
clip
assembly similar to that in FIG. l, this having the hinge pin replaced by a
reduced diameter
hinge hub on the first lever arm and a slot added to the hinge hub of the
second lever arm;
FIG. 17A and 17B are, respectively, sectional, elevational views of the upper
and
lower gripping members of the clip assembly in accordance with another
embodiment of
the present invention, in which the pivot connection is foamed by interfitting
bosses and
sockets on the two members, and in which the hook portion of the upper member
includes
a supplemental opening for attachment to a hook of a shock cord or similar
member;
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8
FIG. 18 is a partial, enlarged elevational view of the lhook portion of the
upper arm
member of FIG. 17B, showing the configuration of the supplemental opening
therein in
greater detail; and
FIG. 19 is a partial, elevational view, similar to FIG . 18, showing the
manner in
which the lower arm member of the clip assembly cooperates with the hook of a
shock
cord or the like so as to exert a gripping force when the latter is received
in the
supplemental opening of the hook portion.
DETAILED DESCRIPTION
a. Overview
FIG. 1 shows a clip assembly 20 in accordance with the present invention, and
FIG.
2 shows this clip assembly engaging a sheet of material 52 and secured by a
rope 54. The
preferred embodiment of the clip assembly 20 is formed of two major members, a
first
gripper arm member 30a (also shown in FIG. 3), and a second gripper arm member
30b
(also shown in FIG. 4), which are joined by a hinge pin 22 in opposition to
each other to
form a pliers like arrangement for gripping a sheet of material 52.
Each of the first and second gripper arm members 30a, 30b includes several
corresponding counterparts including (a) opposing first and second jaw
portions 32a, 32b
that provide structural support for the corresponding first and second grip
elements 34a,
34b which engage the sheet of material 52; (b) first and second lever arm
portions 36a, 36b
that extend from the first and second jaw portions 32a, 32b ~to provide
leveraged activation
of the first and second jaws 32a, 32b; (c) first and second hinge hubs 38a,
38b having holes
44a, 44b that accommodate the hinge pin 22 and provide a common pivot point
for
activating the jaws 32a, 32b via the lever arms 36a, 36b; (d) first and second
sets of lever
arm ridges 40a, 44b that provide ergonomic slip-free platforms for the
operator to squeeze
the lever arms 36a, 36b between his finger and thumb, respectively; and, (e)
first and
second opposed, cooperating ratchet lips 42a, 42b that provide an interim
locking means
that preserves jaw engagement pressure with the sheet 52 even after the user
releases his
hand from the lever arms 36a, 36b.
CA 02484135 2004-10-07
9
In addition, the terminal end of the second lever arm. 36b may be equipped
with a
hooked securement element 50 that concurrently provides a means for connecting
the clip
20 to a rope 54 or similar cord, bungee, or other attachment element, and
which further
serves to lock the lever arms in the activated position until the rope or
other attachment
element is removed.
Although any of the various components comprising each gripper arm member 30a,
30b could be fabricated as an individual part and joined to the assembly by
appropriate
means, it is generally preferable that each gripper arm member 30a, 30b be
formed as a
single integral part incorporating the associated sub-components. This may be
accomplished by injection molding each gripper arm member 30a, 30b of suitable
plastic
such that the entire clip assembly 20 requires only two or three parts, the
first gripper arm
member 30a, the second gripper arm member 30b, and in some embodiments the
hinge pin
22. This arrangement is highly advantageous from the standpoint of simplicity,
economy
of manufacture, and durability. Glass-fiber filled nylon is particularly
suitable for use in
the present invention due to its combination of strength and resiliency,
however, other
materials such as, but not limited to, other plastics, metal, or composites
may also be used
so fabricate the gripper arm members 30a, 30b so long as they provide the
appropriate
amount of strength, resilience and relative compliance fi'r the intended
functionality.
Additionally, other molding, machining, or manufacturing processes may be
employed as
well. The hinge pin may be fabricated from metal, plastic, or some other
material; or it
may be eliminated completely as discussed later with regard to additional
embodiments.
b. Jaws and Grip Elements
The opposing first and second jaw members 32a, 32b may comprise generally
rectangular platforms having generally planar faces 33a, 33b on which the grip
portions
34a, 34b are formed or attached. To provide high contact area and strong grip
strength
while preserving compactness, the jaws 32a, 32b of the :preferred embodiment,
have a
generally rectangular periphery shape approximately 1-'/2 inches wide and 2
inches long.
However, to achieve more contact area for additional grip strength, to
minimize size for
CA 02484135 2004-10-07
5 compact applications, or to meet other design improvements, these dimensions
may be
altered. Furthermore, although the periphery of the jaws on the preferred
embodiment is
generally rectangular other shapes rnay be used, as will also be discussed
below with regard
to additional embodiments.
To resist bending due to the squeezing action of l:he lever arms and to supply
10 uniform pressure to the sheet material 52, the jaws 32a, 32b of the
preferred embodiment
are solid with a generally rectangular crossection approximately 1-'/Z inches
wide and 1/4
inch thick, although other dimensions may be used depending on materials and
other
design factors. To save weight and material cost, the face opposite the grip
face 33a, 33b
may be strategically hollowed out leaving reinforcement ribs.
Although the opposing faces 33a, 33b of the jaws 32a, 32b may be configured to
be
either parallel or divergent when fully closed, it is generally preferable
that they are
arranged to become nearly parallel when a sheet of material 52 of typical
nominal thickness
is engaged between them. This arrangement provides more uniform pressure and,
thus,
enhanced grip. The preferred embodiment utilizes planar faces 33a, 33b on the
jaws 32a,
32b, however, each face could be contoured or fashioned with reliefs that may
or rnay not
nest with the opposing face.
Although various grip type elements and materials may be used, in the
preferred
embodiment the grip portion of each jaw 32a, 32b is formed as a generally
rectangular
array of teeth 34a, 34b for engaging and retaining the sheet material 52. As
illustrated in
Fig. 5 and Fig. 6 the array of teeth 34a on the first grip face 33a may be
configured to be
received in the intersecting valleys between the array of teeth 34b on the
second grip face
33b, and vice versa. By this arrangement, the sheet material 52 is forced into
an interfitting
"egg carton" pattern by the high contact pressure between the jaws, providing
high contact
area and enhanced resistance to pullout in all directions.
As shown in Fig. 6, the individual teeth 34a, 34b are generally pyramidal in
shape
but their peaks rake away from the sheet material and back towards the hinge
point 22.
The nested pyramidal teeth provide high contact pressure to engage the fabric
and resist
pullout. This effect is further enhanced by the rake angle, which opposes the
pulling
direction and thus provides additional contact pressure and more tenacious
gripping action.
CA 02484135 2004-10-07
11
Other teeth shapes and configurations may be substituted for this preferred
embodiment, for example continuous parallel ridges of teeth, circular
arrangements of
teeth, or gumdrop shaped teeth.
c. Lever Arms
Referring to FIG. 1 through FIG. 4, in the preferred embodiment the first
lever arm
36a is a generally rectangular member formed as an integral extension of the
first jaw
portion 32a with an elongated slot 46 to accept the second lever arm 36b. The
second lever
arm 36b, in turn, extends from the grip face 33b of the second jaw member 32b
and has a
generally rectangular cross-section with a width, measured parallel to the
hinge pin axis 22,
which allows it to pass through the slot 46 that provides an opening in the
first lever arm
36a. Both the first lever arm 36a and the second lever arm 36b have hinge hubs
38a, 38b
with concentric holes 44a, 44b that accept hinge pin 22 and serve as the pivot
point for
activating the jaws 32a, 32b. By centering the second lever arm 36b within the
slot 46 of
the first lever arm 36a, the forces and torques generated on the hubs 38a, 38b
and hinge pin
22 by the squeezing pressure are more evenly balanced, minimizing stress on
the parts,
reducing the required lever arm and hub cross-sections, and eliminating the
need for high
strength materials. However, other lever arm configurations may be used. For
instance,
two parallel arms of comparable cross-section, and without any slots, could be
assembled
adjacent to each other with the corresponding extended jaws opposingly offset
from each
arm along the hinge axis to allow them to centrally align along an axis
perpendicular to the
hinge pin and through its midpoint, resembling a conventional set of pliers in
outward
appearance.
The length of the lever arms 36a, 36b determines the amount of leveraged force
that
can be applied to the jaws 32a, 32b and consequently the amount of grip
strength achieved
on the sheet material 52. To provide high grip strength while preserving
compactness, the
lever arms 36a, 36b, of the preferred embodiment, are approximately 3 inches
long.
However, to achieve additional grip strength, the arms may be lenl,~thened,
or, to minimize
size for compact applications, the arms may be shortened. As discussed
previously,
CA 02484135 2004-10-07
12
maintaining appropriate relative bending compliance of the lever arms 36a, 36b
is
necessary to properly operate the interim locking mechanism. and to allow
securement of
the clip 20 to a rope 54 or other attachment element. The cross-sectional
dimensions of the
lever arms 36a, 36b combined with their length and the material from which
they are made
regulates this relative bending compliance. By making the first lever arm
.sc~a
approximately '/4 inch thick, 1 1/2 inches wide and with a '/4 inch slot 46,
and making the
second lever arm 36b approximately '/4 inch thick and just under '/4 inch
wide, an
appropriate compliance is achieved on the preferred embodiment when using
40~/o glass-
filled nylon material. However, these dimensions may be varied to accommodate
variations in lever arm length and material properties, or to achieve
different interim
locking pressures or securement pressures. In addition, other cross-sectional
shapes may
be used for the lever arms 36a, 36b, and the cross-sectional shape and
dimensions may vary
along the length of the arms.
Because the pivot joint may see elevated stresses due to the high clamping
loads,
the lever arms 36a, 36b are fitted with hinge hubs 38a, 38b to reinforce them.
In the
preferred embodiment the hinge hubs 38a, 38b are cylindrical distensions
concentrically
located about the hinge pinholes 44a, 44b. However other hub reinforcement
shapes may
be used or they may be eliminated entirely if adequate strength can be
achieved without
them. In addition, the hinge hub 38b may be widened along the hinge pin 22
axial
direction so as to be nearly as wide as the slot 46 in the first lever arm
36a. The flat faces
of the hubs 38a, 38b would then provide the pivot contact surface for hinged
operation and
the second lever arm width, along the hinge pin 22 axial direction, could be
reduced as
desired.
To aid the operator in squeezing the lever arms 36a, 36b together and in
deflecting
them to activate the interim locking element, each lever arm is preferably
equipped with an
ergonomic slip free platform 40a, 40b having suitable surface texturing. In
the preferred
embodiment, the first lever arm 36a has a platform 40a on its bottom surface
adjacent its
terminal end and comprising a shallow cylindrical recess with a cylindrical
array of parallel
ridges that accepts the operator's index or middle finger. The second lever
arm 36b has a
platform 40b on the crest of its upper surface and comprising a linear array
of parallel
CA 02484135 2004-10-07
13
ridges that accepts the operator's thumb. It will be understood that other
suitable forms of
surface texturing may be employed in the appropriate areas.
By squeezing the thumb and finger together, the lever arms 36a, 36b are
activated,
engaging the jaws 32a, 32b on the sheet material 52. By then deflecting the
thumb and
finger in laterally opposed directions, the lever arms are likewise deflected
such that the
interim locking mechanism may be engaged.
d. Interim Locking Element and Securement Mechanism
The interim locking mechanism for the preferred embodiment is illustrated in
FIG.
7 and comprises two opposed engaging ratchet lips 42a, 42b, one located on
each Lever arm
36a, 36b adjacent its terminal end. The first ratchet lip 42a may be formed
from the edge
of a drafted rectangular depression 48 formed in the bottom surface of the
first lever arm
36a, adjacent the lever arm slot 46 and near its terminal end. The second
ratchet lip 42b
may comprise a triangular protrusion formed on the side of the securement hook
50 with its
ridge pointing towards and opposing the first ratchet lip 42a. The interim
locking
mechanism may be engaged by squeezing the lever arms 36a, 36b together until
the second
ratchet lip 42b is deflected beyond the bottom surface of the first Lever arm
36a, and then
laterally deflecting the lever arms 36a, 36b relative to each other until the
side of the
second lever arm 36b contacts the edge of the slot 46 in the first lever arm
36a. At this
point the ratchet lips 42a, 42b will be vertically aligned such that they
overlap in
embodiment, and engagement can be completed by relaxing the squeeze pressure
on the
lever arms 36a, 36b.
Although the preferred embodiment has a single opposing lip on the hook 50 of
the
second lever arm 36b, a linear array of lips may be used to form a multiple
ratcheting
mechanism that provides variable retained grip pressure. It ',vill be
understood that various
forms of pawls or teeth may be substituted for the ratchet lips that are
shown, or different
interim locking mechanisms may be employed.
Referring to FIG. 1 and FIG. 2, the securement element provides a means of
connecting the clipped sheet of material 52 to a rope 54 or other connective
element that is
CA 02484135 2004-10-07
14
subsequently anchored to a fixed point. In the preferred embodiment, the
securement
element consists of a semi-enclosed hook 50. The hook 50 has a generally
rectangular
cross-section, approximately '/4 inch wide and '/4 inch deep, that extends
from the terminal
end of the second lever arm 36b and arcs approximately 190 degrees. The inner
diameter
may be approximately '/4 inch to accept a rope S4 or bungee of that size or
smaller.
However, the dimensions and section shape of the hook may vary so long as
proper
operation can be sustained without interference of the hook SO with the second
lever arm
slot 46. Use of a hook 50 as the securement element allows a loop of rope 54
or other cord
to be quickly and conveniently pulled over the hook and secured, a great
advantage when
numerous clips 20 are being installed, such as on a large tarp or sheet of
plastic at a
construction site, for example. It may also be advantageous for specific
applications such
as when securing a trucking tarp. With a series of clips 20 installed on the
edge of the tarp
so as to individually align between a series of hooks on the trailer frame, a
rope can then be
zigzagged between the clip hooks (50) and the truck hooks to secure the tarp.
Although a hook 50 is used for the preferred embodiment, other securement
element configurations may also be used. For instance a full annular loop
could be
substituted for the hook 50 and a rope could be fed through the eye and tied.
Or, other
securement means may be combined with the hook 50, such as a hole placed in
the second
lever arm to accept the wire hook found on the ends of many bungee cords. This
hole
would be strategically positioned such that when installed, the bungee hook
would interfere
with the first lever arm slot 46, and provide the same grip jaw preload as the
rope 54 and
hook 50 arrangements.
e. Operation
FIGS. 8-12 illustrate the operation of the clip assembly 20.
In FIG. 8 the clip is open and the sheet material 52 is inserted between the
jaws 32a,
32b. In FIG. 9 the lever arms 36a, 36b opposingly rotate relative to each
other about the
hinge pin 22 as they are squeezed together using the ridged forger and thumb
platforms
40a, 40b. The lever arms 36a, 36b continue to rotate until the teeth 34a, 34b,
of the
CA 02484135 2004-10-07
5 opposing teeth 34a, 34b, contact the sheet material 52 and clench it in an
interfitting pattern
that undulates within the space between the teeth 34a, 34b.
As can be seen in FIG. 10, squeeze pressure is then applied to the lever arms
36a,
36b so that these bend resiliently relative to each other about the hinge pin
axis. When the
second ratchet lip 42b is deflected beyond the bottom surface of the first
lever arm 36a, the
10 interim locking mechanism can be engaged by laterally deflecting the lever
arms 36a, 36b
relative to each other and releasing the lever arm pressure. At this point,
the clip assembly
is in firmly engagement with the sheet material 52, with its grip being
sustained by the
compressive force stored elastically in the deflected lever arms 36a, 36b.
To then secure the engaged clip 20 to a fixed anchor via a rope or other cord,
the
15 lever arms 36a, 36b are squeezed with even greater engagement pressure so
that they
deflect relative to one other until the inner radius of the securement hook 50
passes
completely through the slot 46 in the first lever arm 36a anal is exposed on
the opposite
side of the first lever arm, as is shown in FIG. 11. As can be seen in FIG.
12, a rope 54 or
other cord, can then be looped or tied on the exposed hook 50 so that this
creates an
20 interference between the hook 50 and slot 46 that prevents the lever arms
36a, 36b from
returning to their relaxed state even when finger pressure is removed. A great
deal of grip
pressure can be applied to the sheet material 52 and retained by this
arrangement. As is
shown in FIG 12, the sheet material 52 can then be stretched taut by
tightening the rope 54
and securing it to an anchor. The entire operation may be reversed to remove
the clip 20
and free the tarp or other sheet material 52.
Aside from retaining the clip 20 to the sheet 52, the interim locking
mechanism also
enhances the convenience and speed of attaching the securement rope 54 under
various
circumstances. As is shown in FIG. 10, the securement hook: 50 is partially
exposed on the
opposite side of the first lever arm 36a when in this position. The geometry
of the hook 50
with a rounded ramp leading into its opening, is such that a rope loop can
then be wedged
between the hook tip and first lever arm 36a and pulled so .as to pry the
second lever arm
36b to a more depressed position that allows the rope to seat fully within the
hook 50.
CA 02484135 2004-10-07
16
e. Additional Embodiments
In addition to the preferred embodiment described above, other forms and
variations may be implemented that remain within the spirit and scope of the
invention.
For instance, although the jaws 32a, 32b have a rectangular peripheral shape
and a
rectangular array of teeth 34a, 34b in the preferred embodiment, a circular
jaw
configuration 56 having a circular array of teeth 58 may be used as shown in
FIG. 13.
Other jaw configurations and teeth arrangements may be used as well. In
addition, the
teeth shape may vary, as illustrated by the conical teeth 58 in FIG. 13, or
the teeth may be
replaced or enhanced by other forms of grip elements. For instance, high
friction rubber
pads may serve as a substitute for both sets of gripper teeth on° teeth
may be retained on one
jaw and a rubber pad substituted for the teeth on the opposing jaw or
alternating patterns of
teeth and rubber could be used on a single jaw. This latter arrangement is
illustrated in
FIG. 14, which demonstrates alternating concentric rings of rubber 60 and
conical teeth 62.
Such a configuration may combine the mechanical engagement of teeth with the
frictional
adhesive properties of rubber to provide enhanced grip on the sheet material
A variation of the arrangement illustrated in FIG. 14 is shown in FIG. 15 in
which
an outer rubber lip 64 surrounds the periphery of a rectangular array of teeth
66, and the
edges of the jaw 34a are provided with an appreciable fillet radius 68. By
implementing
these features, concentrated contact pressure between the sheet material and
teeth 66 along
the edge of the jaws 34a may be reduced providing a transition zone that
gradually and
uniformly transfers load into the sheet material, thus preserving the sheet
integrity and
increasing pull-out strength.
In addition to various arrangements for gripping sheet materials, the jaw
portions
may be configured or include portions for gripping or holding a variety of
articles and
materials in addition to or in place of the tarps and sheet materials
described above,
including ropes, rods, railings, and so on, for example.
Another embodiment is shown in FIG. 16. In this example the diameter of the
hinge hub 44a on the first lever arm 36a has been reduced, z.nd a slot 70 has
been added to
the hinge hub 44b on the second lever arm 36b. In this manner, the reduced
diameter hub
CA 02484135 2004-10-07
17
44a substitutes for the hinge pin 22, which can then be eliminated so as to
reduce the total
part count to two and enhance the economy of the assembly. The clip 20 can be
assembled
by sliding the lever arm 36b of the second gripper/arm assembly 30b through
the slot 46 in
the first gripper/arm assembly 30b and then inserting the reduced diameter hub
into the slot
70. Retaining lips may be added to the hub slot 70 to lock the joint in place,
in which case
a snap fit may be used for assembly.
FIGS. 17A-17B show the upper and lower arm members for the clip assembly in
accordance with another embodiment of the present invention, this being
generally similar
to the embodiments described above except for the structure forming the pivot
connection
between the arm members and also an inclusion of a supplemental opening in the
hook
portion of the upper arm member for cooperating with the hook at the end of a
shock cord
or the like.
With regard to the pivot connection, it can be seen that the upper arm 82 of
the
assembly includes a pair of generally cylindrical bosses 84 that protrude
laterally on both
sides of the pivot hub 86. The hub portions 88 of the lower pivot arm 90, in
turn, include
corresponding generally cylindrical sockets 92 that are sized and shaped to
form a pivoting
interfit with the bosses 84 of the upper lever arm. On the upper side of each
of the sockets
92 there is an opening 94 having a width slightly smaller than the diameter of
the bosses
84. Channels 96, in turn, extend vertically through the rearward portions of
the hubs 88
and have a width that is larger than the diameter of the bosses. To connect
the two arm
members and therefore assemble the clip assembly, the arm portion 100 of the
upper lever
arm is passed through the longitudinal opening 102 in the lower arm, and the
two bosses 84
are slid upwardly through channels 96 in the direction indicated by arrow 94.
The bosses
are then moved forwardly and downwardly into the sockets 92, in the direction
indicated by
arrow 106. As this is done, a ramp portion 108 on the upper edge of the wall
110 between
the channels and sockets helps to guide the hubs into the sockets and also
aids in bending
wall 110 rearwardly in response to a downward pressure on the bosses in the
direction
indicated by arrow 106. The causes openings 94 to spread to a sufficient width
that the
bosses 84 are able to fully enter the sockets 92, after which i:he wall 110
returns resiliently
CA 02484135 2004-10-07
18
to its original position so that the bosses are retained in piivoting
engagement with the
sockets.
Once assembled, forces on the bosses 84 that are generated by the clamping
action
of the jaw portions 112, 114 are transferred into and born by a thick wall
portion 114 of the
hubs that surrounds the lower ends of the sockets 92, rather tlhan at the
openings, 94. The
embodiment shown in FIGS. 17A-17B thus forms a rapidly assembled pivot
connection
that is not subject to spreading and does not require a separate pivot pin.
As noted above, in the embodiment shown in FIGS. 17A-l7B also includes a
supplemental opening in the hook portion 116 at the end of the upper lever
arm. As can be
seen in FIG. 18, the supplemental opening 120 is formed as a small, generally
cylindrical
opening within the upper, rearward portion of the main opening 122 of the hook
portion
116, the latter functioning to hold a rope or other cord in essentially the
same manner as
described above. The supplemental opening 120, in turn, is sized to have a
diameter
approximately equal to or larger than the diameter of the material forming a
hook on the
end of a shock cord (commonly referred to as a "bungee cord"), such hooks
conventionally
being formed by heavy gauge bent wire. As can be seen in FIG. 18, the lower
side of the
supplemental opening is formed by somewhat hook-shaped wall 124 having upper
lip that
projects upwardly at the entrance into the opening.
Thus, to use the clip assembly with a shock cord, the upper and lower lever
arms
are pressed together so as to exert a gripping force in the manner described
above, until the
hook portion of the upper lever arm deflects resiliently downwardly to a point
where the
secondary opening 120 is located slightly below the lower lever arm 90, as
shown in FIG.
19. The hook 126 on the shock cord (shown in cross section in FIG. 19) is then
inserted
into the secondary opening in the direction indicated by arrow 128. When
finger pressure
is released, the lower surface 130 of the lower lever arm bears against the
hook 126,
preventing the lever arms from spreading apart and thereby maintaining the
grip exerted by
the clip assembly. Simultaneously, the upwardly-projecting lip of the hook-
shaped wall
124 on the one side and the pressure of the lower lever arm '90 on the other
cooperate to
hold the hook 126 normally in place and prevent it from escaping from opening
120.
CA 02484135 2004-10-07
19
In this manner, a secondary hook opening in the embodiment shown in FIGS. 18-
19
(which may be used in other embodiments in addition to that having the form of
pivot
connection shown in FIGS. 17A-17B) allows very quick and secure attachment of
top
cords to tarps and the like, with the operator simply squeezing the lever arms
of the clip in
one hand and inserting the hook of the shock cord with the other.
The foregoing description of the preferred embodiment of the invention has
been
presented for the purpose of illustration and description. It is not intended
to be exhaustive
or to limit the invention to the precise form disclosed. Many modifications
and variations
are possible in light of the above teaching.
