Note: Descriptions are shown in the official language in which they were submitted.
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RELEA~ABLE LADDER FASTENER
The invention relates to elongate ladder fasteners for
releasably securing discrete elongate objects together to form a
bundle and for securing the bundle to a mounting surface.
BACKGROUND OF THE INVENTION
Many varieties of fasteners having ladder strap portions and
an integral locking head have been proposed for securing wires
or the like in bundles. A number of these fasteners include
structures that pxovide for the attachment of the fastener and
the bundle o wires secured by the fastener to a mounting
surface. It is desirable that a fastener be easily applied,
positively locking to ensure that it ~oes not inadvertently
release a bundle of wires and at the same time easily releasable
to allow access to the wire bundle.
~lthough a number of proposed fastener structures are stated
to be positively locking, releasable and specially adapted to
secure the fastener to a mounting surface, the actual ease of
application and releasability of these fasteners leaves signifi-'
cant room for improvement in the art. The proposed fasteners
require careful manipulation and/or require the application of
high application forces to secure the ladder strap to a locking
head and require either very careful manipulation or the
application of brute force to release the ladder strap from the
locking head.
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SUMMARY OF THE INVENTION
Among the several objects of the present invention may be
noted the provision of a ladder fastener that positively and
reliably locks to encircle and fasten a bundle of wires or the
like; the provision of a ladder fastener that is easily applied;
the provision of a ladder fastener that can be easily released
to allow access to a bundle secured therein; the provision of a
ladder fastener that is specially adapted to secure the fastener
to a mounting surface; and the provision of a ladder fastener
that has a one-piece construction and is economical and simple
to manufacture.
In general, a releasable ladder fastener includes a ladder
strap portion having a pair of elongate parallel rails joined by
a plurality of spaced lnterposed rungs, a fastener mounting
means for securing the fastener to a mounting surface formed
adjacent an end of the strap portion and resilient latching
means formed on the fastener mounting means for engaging the
side rails of the strap portion with two spaced apart opposed
resiliently mounted locking members within respective side rail
latching recesses o the locking members to releasably lock the
resilient latching means within the ladder strap portion.
BRIEF DESCRIPTION OF TME DRAWINGS
FIG. 1 is a perspective drawing of a releasable ladder tie
embodying the concept of the present invention shown securing a
bundle of wires to a stud.
FIG. 2 is a plan of the fastener of FIG. 1.
FIG. 3 is a side view of the fastener of FIG. 1.
FIG. 4 is a sectional view of the fastener of FIG. 1 taken
along line 4-4 of FIG. 2.
FIG. 5 is a sectional view of the stud mount boss of the
fastener of FIG. 1 taken along line 5-5 of FIG. 2.
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FIG. 6 is a sectional view of the ladder strap of the
fastener of FIG. 1 taken along line 6-Ç of FIG. 2.
FIG. 7 is a sectional view of the fastener of FIG. 1 as
applied around a bundle of wires.
PREFERRED EMBODIMENT FOR
CARRYING OUT THE INVENTION
A releasable ladder fastener embodying the concept of the
present invention is designated generally by the number 10 in
the accompanying drawings. Fastener 10 is preferably of
injection molded integral thermoplastic construction.
Fastener 10 includes a ladder strap 12, a stud mount boss 14
and a releasable latch 16.
Ladder strap 12 includes spaced parallel coextensive side
rails 18 extending between and connecting a tapering truncated
tip 20 and stud mount boss 1~. Rungs 22 are disposed perpen-
dicular to side rails la and are equally spaced along the length
thereof to join parallel side rails 18 to form ladder strap 12.
Rungs 22 are formed having a radius at leading and trailing
faces 24 and 26, as seen in the sectional drawing of rungs 22 in
FIG. 4.
Stud mount boss 14 includes a cylindrical socket 28, having
a formed stud mount bore 30. Three resilient fingers 32 and
three guidance ribs 34 are formed within bore 30. Resilient
fingers 32 are equally spaced around the circumference of bore ,
30, disposed to project radially inwardly, as seen in FIG. 2,
with their centerlines aligned to intersect the center line of
bore 30. One of resilient fingers 32 is formed on the portion
of socket 28 adjacent releasable latch 16 with its length being
aligned with the centerline of ladder strap 12. As seen in FIG.
5, resilient fingers 32 project upwardly from a stud entry face
36 towards a,stud exit face 38 of socket 28 forming a 45 degree
angle with the centerline of socket 28.
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Guidance ribs 34 project radially inwardly, as seen in FIG.
2, with their center lines aligned to intersect the center of
bore 30; guidance ribs 34 being equally spaced around the
circumference of bore 30. As seen in FIG. 2, one of guidance
ribs 34 is formed on the portion of socket 28 adjacent ladder
strap 12 with its length being aligned with the centerline of
ladder strap 12. Guidance ribs 34 extend substantially the
length of bore 30 tapering outwardly adjacent entry face 36.
Guidance ribs 34 define the maximum diameter of a stud that can
be utilized to mount fastener lo. Resilient fingers 32 extend
radially inwardly past guidance ribs 34 and are protected from
stress induced plastic deformation by quidance ribs 34; guidance
ribs 34 preventing the expansion of fingers 32 beyond their
resilient limit.
Releasable latch 16 includes two opposed locking members 40
formed on the portion of socket 2~ ad~acent stud exit face 38
and extending in the opposite direction of ladder strap 12. As
seQn in FIG. 3, loaking members 40 preferably extend outwardly
of stud exit face 3~ at an angle o~ 20 degrees to the plane of
~he face of stud exit face 38 or ladder strap 12. Each locking
member 40 includes a head portion 42 the periphQral contour of
which, as seen in FIG. 2, tapers outwardly from the outermost
extent of locking member 40 until it extends inwardly at a side
rail latching recess 44 to form a locking barb 46. The 20
degree outward disposition of locking members 40 advantageously
presents head portions 42 of locking members 40 at an optimal
position spaced from stud entrance face 36, and thus the
mounting surface, facilitating the release of ladder strap 12 of
a mounted fastener 10 by providing sufficient clearance to
effectively grasp and re~ease releasable latch 16; any greater
angle causing locking members 40 to unnecessarily increase the
overall height of an applied fastener 10 when used to fasten
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small bundles and any lesser angle reducing the ease of manipu-
lation of releasable latch 16.
Referring now to FIG. 3, the bottom contour of each locking
member 40 tapers downwardly from the outermost extent of locking
member 40 until it extends upwardly at rung latching recess 48
to form a locking ridge 50. Locking ridges 50 of locking
members 40 are aligned to receive a rung 22.
Each opposed locking member 40 is resiliently mounted to
socket 28 by forming a section of reduced thickness in each
locking member 40 adjacent hinge recesses 52 to increase the
flexibility of locking members 40. The flexibility of locking
members 40 can be selected by varying the depth of hinge
recesses 52 to select the desired level of force necessary to
insert and release latch 16. The height of each locking member
40, as seen in FIG. 4, is increased at the region of reduced
thickness of locking members 40 to provide increased tensile
strength in locking member 40 in the direction of its length to
counter balance the reduction ln tensile strength caused by the
areas of reduced thiakness. Spaced apart locking members 40 are
ormed such that inward forcQ applied to locking members 40
resiliently deforms the members 40 inwardly and removal of the
inward force allows the locking members 40 to return to their as
molded position. Gripping ridges 54 are formed on the outwardly
directed surfaces of head portion 42 to facilitate manual
deformation of locking members 40.
Referring now to FIGS. 1 and 7, fastener 10 is applied by
encircling the wires to be fastened with ladder strap 12, and
inserting releasable latch 16 between adjacent rungs 22.
Locking members 40 resiliently deform inwardly as they are
inserted between adjacent~rungs 22; biasing opposed locking
barbs 46 outw,ardly against side rails 18 to engage side rails 18
within side rail latching recesses 44. In addition the one of
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the adjacent rungs 22 closest strap tip 20 of ladder strap 12 is
received within aligned rung latching recesses 48 of locking
members 40 to secure ladder strap 12 to releasable latch 16.
Fastener 10 can be released by displacing locking members 40
inwardly and withdrawing ladder strap 12 to remove releasable
latch 16 from ladder strap 12. An applied fastener 10 can also
be simply and quickly released with one hand by grasping strap
tip 20 and pulling ladder strap 12 away from the mounting
surface with sufficient force to deform locking members 40
inwardly and release ladder strap 12 from releasable latch 16.
Fastener 10 can be mounted to a stud having a distal collar
as shown in FIG. 7 or mounted to a threaded stud, bolt or the
like by inserting the stud into stud mount bore 30 at stud entry
face 36 either be~ore or after fastener 10 is secured around a
bundle. The height of a mounting stud is selected to prevent
the stud from pro~ecting past ~tud exit face 38 to protect wires
bundled within fastener 10.
