U.S. patent application number 11/879135 was filed with the patent office on 2007-11-08 for pivot handle for use with expansible hole anchor.
This patent application is currently assigned to Sigma Industries, LLC. Invention is credited to Eric William Reeves.
Application Number | 20070257171 11/879135 |
Document ID | / |
Family ID | 46328120 |
Filed Date | 2007-11-08 |
United States Patent
Application |
20070257171 |
Kind Code |
A1 |
Reeves; Eric William |
November 8, 2007 |
Pivot handle for use with expansible hole anchor
Abstract
A pivot handle operable for use with conventional hole anchor
devices is provided and generally includes an assembly of links and
rockers attached together on opposite sides of the load cable by
fasteners. Respective ends of the hole anchor's chock cables are
fixed to the rockers. When assembled about the load cable of the
hole anchor, the rockers cooperate to allow kink-controlling
movement of the chock cables relative to the load cable. The handle
rocks or pivots when one chock cable is in tension and the other
cable is in compression, thereby discouraging cable kinking or
excessive bending which may foul effective operation of the anchor.
To facilitate retraction of the handle, finger curves formed with
the rockers are also provided.
Inventors: |
Reeves; Eric William;
(Charlotte, NC) |
Correspondence
Address: |
Jason S. Miller;CLEMENTS WALKER
Suite 300
1901 Roxborough Road
Charlotte
NC
28211
US
|
Assignee: |
Sigma Industries, LLC
|
Family ID: |
46328120 |
Appl. No.: |
11/879135 |
Filed: |
July 16, 2007 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
11069646 |
Mar 1, 2005 |
7258316 |
|
|
11879135 |
Jul 16, 2007 |
|
|
|
PCT/US04/24129 |
Jul 27, 2004 |
|
|
|
11069646 |
Mar 1, 2005 |
|
|
|
Current U.S.
Class: |
248/231.9 |
Current CPC
Class: |
E04G 21/3261 20130101;
A62B 35/0068 20130101; A63B 29/024 20130101; E04G 21/3276
20130101 |
Class at
Publication: |
248/231.9 |
International
Class: |
A47F 5/08 20060101
A47F005/08 |
Claims
1. An expansible hole anchor adapted for insertion into a hole
formed within a structure, said hole anchor comprising: a load
cable; a center chock attached to an end of said load cable; at
least one side chock adjacent to said center chock and adapted for
movement between an anchor-contracting position and an
anchor-expanding position; and a pivot handle carried by said load
cable and adapted for moving said at least one side chock from the
anchor-expanding position to the anchor-contracting position, and
whereby in said anchor-contracting position, said anchor is readily
inserted into and removed from the hole of the structure, and in
said anchor-expanding position, said anchor is locked inside the
hole of the structure.
2. The expansible hole anchor according to claim 1, further
comprising a chock cable interconnecting said pivot handle and said
at least one side chock.
3. The expansible hole anchor according to claim 1, wherein said
pivot handle comprises a link assembly movably joined to a rocker
assembly for allowing kink-controlling movement of said chock cable
relative to said load cable.
4. The expansible hole anchor of claim 3, wherein the link assembly
is a plurality of links, each link being joined to a surface of the
rocker assembly such that the pivot handle is mounted about the
load cable.
5. The expansible hole anchor of claim 3, wherein finger curves are
formed with the rocker assembly for facilitating retraction of the
pivot handle along the load cable.
6. The expansible hole anchor of claim 3, wherein the rocker
assembly comprises at least two rockers having substantially planar
top and bottom portions and a side wall.
7. A pivot handle, comprising: at least one rocker assembly; a
plurality of links movably joined to the at least one rocker
assembly by at least one fastener; and wherein the pivot handle is
mounted about a load cable of an expansible hole anchor, and
wherein an end of at least one chock cable is fixed to the at least
one rocker assembly such that the pivot handle provides
kink-controlling movement of the at least one chock cable relative
to the load cable.
7. The pivot handle of claim 6, wherein the at least one rocker
assembly comprises substantially planar top and bottom portions and
a side wall.
8. The pivot handle of claim 7, further comprising finger curves
formed with the at least one rocker assembly for facilitating
retraction of the pivot handle along the load cable.
9. A pivot handle for use with an expansible hole anchor,
comprising: a pair of rockers having substantially planar top and
bottom portions and a side wall; a first link movably joined to the
top portions of the rockers and a second link movably joined to the
bottom portions of the rockers; attachments means for receiving
respective ends of a plurality of chock cables such that the pivot
handle pivots when one chock cable is in tension and the other
cable is in compression, thereby discouraging cable kinking;
wherein the pivot handle is movably mounted about a load cable of
an expansible hole anchor.
10. The pivot handle of claim 9, wherein at least one bore
extending through the top portion to the bottom portion of each
rocker is provided for receiving a fastener for movably joining the
links to the rockers.
11. The pivot handle of claim 10, wherein the fastener is selected
from the group consisting of a rivet, a pin, a screw and a
wireform.
12. The pivot handle of claim 9, further including finger curves
formed in the side wall of the rockers for facilitating retraction
of the pivot handle along the load cable.
Description
CROSS REFERENCE TO RELATED APPLICATION(S)
[0001] This application is a continuation-in-part of U.S. patent
application Ser. No. 11/069,646, filed on Mar. 1, 2005, and
entitled "EXPANSIBLE HOLE ANCHOR WITH ENLARGED CHOCK-RELEASING
STRIKER HEAD," which is a continuation of and claims the benefit of
priority of PCT/US04/24129, filed on Jul. 27, 2004, the content of
all the aforesaid applications are relied upon and incorporated by
reference in its entirety.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates generally to safety devices
and methods for fall protection, and more specifically, to safety
devices including, in an exemplary embodiment, a pivot handle
operable for use with conventional expansible hole anchors and the
like.
[0004] 2. Technical Background
[0005] In the construction industry, it is often necessary to
provide fall protection for workers or objects suspended at
heights. Conventionally, expansible hole anchor bolts are used to
meet these needs. Contractors typically utilize the expansible hole
anchors in the hopes that they provide a simple, reliable and
relatively inexpensive means for connecting a cable, rope or wire
to a drilled hole in a hard material, that is easy to install in
and remove from the hole, and that effectively anchors to the hole
while applying a minimum stress to the hole, while providing a
minimum sensitivity to the angular orientation of the expansion
bolt in the hole. However, substantial drawbacks and limitations
exist in conventional expansible hole anchors, particularly those
with retractable handles and/or collars.
[0006] A first shortcoming of conventional hole anchors is that the
handle is only applicable for moving the anchor from a normal
expanded condition to a contracted condition for inserting and
removing the anchor from the hole. In order to remove the anchor,
the user is typically instructed to manually retract the handle to
disengage the anchor chocks from an inside wall of the hole. In
many cases, the anchor is so tightly lodged inside the hole that
movement of the handle is difficult, if not impossible. This occurs
often, as the operating instructions call for a tug on the load
cable to set the anchor during insertion. Additional forces exerted
on the anchor caused by a worker movement, or during a worker's
fall cause even greater locking engagement of the anchor chocks.
The instructions commonly provided for dislodging an embedded
anchor are to insert a small, narrow flat screwdriver into the
hole, and create an impact force on an end fitting to overcome the
locking friction. In practice, this procedure is generally
ineffective; often resulting in mangled or broken retraction
cables, and rendering the anchor unsuitable for future use. This
procedure further inconveniences the user by requiring the
availability of special tools in order to access and release the
anchor chocks. If all methods of removal fail, the exposed portion
of the anchor is torched off, a new hole drilled, and the balance
of the anchor is left in the old hole.
[0007] A further problem of conventional anchors relates to the
exposure of control cables operable for moving the anchor from the
expanded condition to the contracted condition. Typically, these
cables will bear directly against an inside wall of the anchor
hole, resulting in substantial abrasion and chaffing when the
anchor is inserted into and removed from the hole. Further wear is
created when the worker moves about causing the control cables to
grind against the concrete lip of the hole. If left undetected, the
worn cables will eventually foul the cable motion and cause the
anchor to fail which may result in inoperability, serious injury,
or death.
[0008] A further problem with conventional hole anchors is the
number of components required for assembly and use. Existing hole
anchors require a large number of parts which disadvantageously
increase the complexity and cost of manufacture. In addition,
conventional hole anchors, are provided with chock cables which may
kink caused by movement of the unit during normal use.
[0009] Accordingly, it would be desirable to have an improved
expansible hole anchor which overcomes the noted shortcomings of
conventional devices. In one such solution, it would be desirable
to provide a pivot handle operable for use with an expansible hole
anchor which reduces the costs of replacement units and/or
components caused by having the chock cables kink or become frayed.
Such a pivot handle would eliminate the possibility of kinking of
the chock cables during normal use of the hole anchor.
SUMMARY OF THE INVENTION
[0010] The present invention is designed to overcome the
deficiencies and shortcomings of the devices described above. The
present invention is designed to reduce the costs of replacement
units and/or components caused by having chock cables of the hole
anchor kink or become frayed. In all exemplary embodiments, the
present invention relates to an improved expansible hole anchor
having a pivot handle that advantageously eliminates kinking of
chock cables. The present invention is easily installed and removed
from a hole formed with a solid structure. In one application, the
present invention discloses a pivot handle operable for use with
hole anchor that is inserted into a hole drilled in a concrete wall
at a construction site. A safety harness, lifeline, and other fall
protection gear is secured to the worker and to the anchor to
arrest the worker in the event of a fall. In another application,
the present invention is directed to a pivot handle for use with a
hole anchor that is applicable for use in securing equipment, such
as scaffolding, to a concrete structure, or as a lift connection
point for items with a suitable hole, such as preformed concrete or
boulders, or for use in recreational rock climbing.
[0011] In all exemplary embodiments, the pivot handle may be used
with an expansible anchor adapted for inserting into a hole formed
with a structure is provided. The hole anchor may generally include
a load cable, a center chock attached to an end of said load cable,
at least one, but preferably two, side chocks adjacent to said
center chock and adapted for movement between an anchor-contracting
position and an anchor-expanding position, whereby in said
anchor-contracting position, said anchor is readily inserted into
and removed from the hole of the structure, and in said
anchor-expanding position, said anchor is locked inside the hole of
the structure. Preferably, a chock cable is provided and
interconnects the pivot handle and the at least one side chock.
[0012] According to an exemplary embodiment, the pivot handle
generally includes an assembly of links and rockers movably
attached together on opposite sides of the load cable by fasteners.
Respective ends of chock cables may be fixed to the rockers. When
assembled the rockers cooperate to allow kink-controlling movement
of the chock cables relative to the load cable. The handle rocks or
pivots when one chock cable is in tension and the other cable is in
compression, thereby discouraging cable kinking or excessive
bending which may foul effective operation of the anchor.
Preferably, to facilitate retraction of the handle, finger curves
are formed with the rockers.
[0013] Additional features and advantages of the invention will be
set forth in the detailed description which follows, and in part
will be readily apparent to those skilled in the art from that
description or recognized by practicing the invention as described
herein, including the detailed description which follows, the
claims, as well as the appended drawings.
[0014] It is to be understood that both the foregoing general
description and the following detailed description present
exemplary embodiments of the invention, and are intended to provide
an overview or framework for understanding the nature and character
of the invention as it is claimed. The accompanying drawings are
included to provide a further understanding of the invention, and
are incorporated into and constitute a part of this specification.
The drawings illustrate various embodiments of the invention, and
together with the detailed description, serve to explain the
principles and operations thereof.
BRIEF DESCRIPTION OF THE DRAWINGS
[0015] These and other features, aspects and advantages of the
present invention are better understood when the following detailed
description of the invention is read with reference to the
accompanying drawings, in which:
[0016] FIG. 1 is a perspective view of a conventional expansible
hole anchor used in conjunction with an exemplary embodiment of the
pivot handle of the present invention;
[0017] FIG. 2 is an exploded view of the conventional hole anchor
and an exemplary embodiment of the pivot handle of FIG. 1;
[0018] FIG. 3 is a side view of the hole anchor and pivot handle of
FIG. 1 with the side chocks in an anchor-expanding position;
[0019] FIG. 4 is a side view of the hole anchor and pivot handle of
FIG. 1 with the side chocks in an anchor-contracting position;
and
[0020] FIG. 5 is a side view of another conventional hole anchor
used in conjunction with an exemplary embodiment of the pivot
handle of the present invention and shown with the side chocks in
an anchor-expanding position.
DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS
[0021] The present invention will now be described more fully
hereinafter with reference to the accompanying drawings in which
exemplary embodiments of the invention are shown. However, this
invention may be embodied in many different forms and should not be
construed as limited to the embodiments set forth herein. These
exemplary embodiments are provided so that this disclosure will be
both thorough and complete, and will fully convey the scope of the
invention to those skilled in the art. Like reference numbers refer
to like elements throughout the various drawings. Further, as used
in the description herein and throughout the claims that follow,
the meaning of "a", "an", and "the" includes plural reference
unless the context clearly dictates otherwise. Also, as used in the
description herein and throughout the claims that follow, the
meaning of "in" includes "in" and "on" unless the context clearly
dictates otherwise.
[0022] The present invention overcomes the shortcomings of
conventional hole anchors by providing a pivot handle about the
load cable and fixed to the chock cables such that kinking of the
chock cables is prevented or altogether eliminated. The use of the
pivot handle reduces the overall cost associated with replacement
hole anchors caused by unit failure, chock cable fraying, etc.
[0023] In exemplary embodiments of the present invention, a pivot
handle for use with an expansible hole anchor is provided. As is
known in the art, an expansible hole anchor may generally include a
load cable having a center chock connected to one end and a loop at
the opposite end, at least one side chock abutting the outer
surfaces of the center chock such that they may translate between
an expanded position and a retracted position, the pivot handle
interconnected to the at least one side chock by at least one chock
cable, a retractor spring to bias the at least one side chock in
the extended position, and a chock release column having an
enlarged head and being interposed between the pivot handle and the
center chock.
[0024] In exemplary embodiments, the expansible hole anchor is
generally operated by pulling back the pivot handle which retracts
the at least one side chock, reducing the outside diameter over the
combination of the center chock and the at least one side chock.
The anchor is then inserted into a hole (in rock, concrete, etc.)
and the pivot handle is released. Spring pressure causes the at
least one side chock to translate along the center chock and expand
to the hole diameter. When tension is placed upon the load cable,
it pulls the center chock outward. The at least one side chock
tends to remain stationary because of friction between the hole and
their outer surfaces. This, in turn, results in the center chock
being driven between the at least one side chock, expanding
laterally and increasing the outward gripping pressure. The greater
the external load placed upon the anchor, the higher the gripping
pressure.
[0025] To release the anchor, the pivot handle is again retracted.
This, in turn, retracts the at least one side chock to a diameter
smaller than the hole. If the pivot handle is stuck in position, an
enlarged head of the chock release column, exposed outside the
hole, may be pushed by hand or struck with a hammer or other tool
to dislodge the center chock and allow the at least one side chock
to retract.
[0026] Referring now specifically to the drawings, a conventional
expansible hole anchor which may be used in conjunction with a
pivot handle constructed in accordance with an exemplary embodiment
of the present invention is illustrated in FIG. 1, and shown
generally at reference numeral 10. The hole anchor 10 is adapted
for inserting into a hole formed with a solid structure, such as a
concrete wall, and is applicable for use with a safety harness,
lifeline, and other fall protection gear worn by a worker to arrest
the worker in the event of a fall. In exemplary embodiments, the
anchor 10 may comprise a load cable 11 looped at one end 12 for
attaching the lifeline, and an assembly of chocks 14, 15, and 16
located at an opposite end. It will be understood by those skilled
in the art that the load cable 11 may be comprised of a steel wire
or any other suitable materials including but not limited to a rod
or a rod like structure. The chocks 14, 15, and 16 cooperate, as
described below, to constrict and expand the anchor 10 relative to
the hole of the structure.
[0027] As best shown in FIGS. 1 and 2, the center chock 15 has a
generally wedge-shaped body, arcuate shoulders 17 and 18, and an
integrally-formed rearward extending cable connector 19. However,
it will be understood by those skilled in the art that the center
chock 15 may have any of a variety of shapes, including, but not
limited to conical and frusto-conical. The cable connector 19
attaches the center chock 15 directly to the load cable 11. The
side chocks 14 and 16 reside adjacent the center chock 15, and have
complementary angled profiles designed to provide maximum uniform
gripping action when set inside the structure hole. The outside
surface of each side chock 14 and 16 is preferably curved to
conform to an inside wall of the structure hole, while the inside
surface is substantially flat for sliding along a flat outside
surface of the center chock 15. In an alternative embodiment, the
inside surface of each side chock is slightly convex, while the
outside surfaces of the center chock are either flat or slightly
concave. In yet another alternative embodiment, the hole anchor may
be adapted for use with crevice gripping or climbing aids. In such
an embodiment, the side chocks may be provided with outside
surfaces which are planar or substantially planar in configuration
to conform to an inside wall of a crevice.
[0028] The side chocks 14 and 16 are attached to respective chock
cables 21 and 22. The chock cables 21, 22 extend rearward to a
pivot handle 25. The pivot handle 25 is carried on the load cable
11, and is adapted for being manually retracted by the user to move
the side chocks 14, 16 from a normal anchor-expanding position,
best shown in FIGS. 1 and 3, to an anchor-contracting position
shown in FIG. 4. In the anchor-contracting position, the side
chocks 14,16 are more closely spaced apart on opposite sides of the
center chock 15 and immediately forward of the arcuate shoulders 17
and 18, such that the anchor 10 is readily inserted into and
removed from the hole of the structure. The spaces 26 and 27 formed
between the shoulders 17 and 18 allow passage of the chock cables
21, 22 rearwardly towards the handle 25. The rear portion of the
center chock 15 is relatively thin, thereby allowing substantial
contraction of the anchor 10. Preferably, the thinnest section of
the center chock 15 forward of the arcuate shoulders 17, 18 has a
profile dimension less than the diameter of the load cable 11 (See
FIGS. 3 and 4). In the anchor-expanding position, the side chocks
14, 16 are urged forward along diverging outer surfaces of the
center chock 15. In use, the anchor 10 does not fully expand inside
the hole, but instead forces the side chocks 14, 16 into sufficient
frictional engagement with the inside wall of the structure hole to
prevent inadvertent dislodging of the anchor 10. After inserting
the anchor 10 into the hole, the side chocks 14, 16 are set by one
controlled pull on the cable loop 12.
[0029] Referring again to FIGS. 1 and 2, a chock-release column 30
may be provided and carried on the load cable 11 adjacent the
center chock 15. Such a chock release column 30 may comprise a
separate cable cylinder 31 and enlarged-diameter head 32. In other
embodiments, the chock release column 30 may be integrally formed
with the cable cylinder 31 and the head 32. The cable cylinder 31
is positioned over the cable connector 19 of the center chock 15
and bears directly against the arcuate shoulders 17, 18. The
enlarged head 32 locates outside of the structure hole, and defines
a flat annular striking or bearing surface 32A designed to receive
a force applied using the thumbs or any rigid object, such as a
snap hook. The force is transferred directly through the
chock-release column 30 to the center chock 15 to dislodge the side
chocks 14, 16 from friction-locking engagement inside the hole.
Once dislodged, the side chocks 14, 16 are easily retracted by the
handle 25; moving from the anchor-expanding position to the
anchor-contracting position to remove the anchor 10 from the
structure hole. A cylindrical spacer 34 and coil spring 35 are
carried on the load cable 11 rearward of the chock-release column
30, and cooperate to maintain the cable cylinder 31 and enlarged
striking head 32 in an engaged, assembled condition with the cable
cylinder 31 bearing directly against the shoulders 17, 18 of the
center chock 15.
[0030] In exemplary embodiments, the maximum diameter of the
striking head 32 is greater than the maximum distance between the
side chocks 14 and 16 in the anchor-expanding condition. As such,
upon insertion of the anchor 10 into the hole, the enlarged
striking head 32 is pushed directly against the mouth of the hole,
thereby locating the anchor chocks 14, 15, and 16 inside the hole
in a position of maximum effectiveness and safety, while
maintaining ready access to the exposed striking surface 32A. When
the cable loop 12 is pulled vertically by the weight of the worker,
the chock-release column 30 flexes slightly at a joint between the
cable cylinder 31 and the enlarged head 32. The outer flange of the
head 32 engages the structure outside of the hole to help
distribute forces acting on the load cable 11 and the
structure.
[0031] According to one embodiment, the enlarged head 32 of the
chock-release column 30 has three openings for receiving the load
cable 11 and chock cables 21, 22, respectively. Preferably, the
center opening has a radiused edge to minimize wear on the load
cable 11 when pulled vertically. A reduced diameter, integral neck
36 extends forward of the enlarged head 32 has interior passages or
longitudinal exterior grooves to designed receive the chock cables
21, 22. The neck 36 cooperates with the arcuate shoulders 17, 18 to
further position the side chocks 14, 16 relative to the center
chock 15. The chock cables 21, 22 extend from the side chocks 14,
16, and are directed along a length of the anchor 10 by a fixed
positioning block 38 located adjacent the pivot handle 25. The
positioning block 38 likewise has three openings for receiving the
load cable 11 and chock cables 21, 22, respectively. In order to
limit twisting of the anchor 10, rotation of the chock-release
column 30 relative to the center chock 15 is prevented by mating
notches and fingers.
[0032] In exemplary embodiments, the pivot handle 25 generally
comprises a link assembly having a plurality of links 41, 42, 43,
44 and a rocker assembly having a plurality of rockers 45, 46 (See
FIG. 2) movably attached together on opposite sides of the load
cable 11 by fasteners 48. As illustrated, four links are provided
and movably attached to two rockers by the fasteners. However, it
will be understood by those skilled in the art that any number of
links may be used. By way of example, links 41, 42 and links 43, 44
may be integrally formed with each other thereby providing two
unitary links, as opposed to the illustrated example of four. These
two unitary links may, in turn, be movably attached to the rockers
45, 46 by the fasteners 48. Also as illustrated, the fasteners 48
are depicted as rivets, however, it will be understood by those
skilled in the art that the fasteners 48 may be screws, pins,
wireform(s), or the like. Respective ends of the chock cables 21,
22 are fixed to the rockers 45, 46. Advantageously, when assembled,
as shown in FIGS. 1, 3, 4 and 5, the links 41, 42, 43, 44 and the
rockers 45, 46 cooperate to allow kink-controlling movement of the
chock cables 21, 22 relative to the load cable 11. The handle 25
rocks or pivots when one chock cable 21, 22 is in tension and the
other cable 21, 22 is in compression, thereby discouraging cable
kinking or excessive bending which may foul effective operation of
the anchor 10. Further, the use of the pivot handle 25 in
conjunction with the chock cables 21, 22 prevents and/or eliminates
fraying of the chock cables 21, 22 during use.
[0033] In exemplary embodiments, the rockers 45, 46 include top and
bottom surfaces 56, 57 which are substantially planar. Further, the
rockers 45, 46 include a continuous side wall 58. In exemplary
embodiments, finger curves 59, 60 may be formed into the side wall
58 for facilitating retraction of the handle 25. The rockers 45, 46
may also be provided with a plurality of bores 61 for receiving the
fasteners 48. In other exemplary embodiments, the bores may be
slots.
[0034] A washer 51 and retractor spring 52 are carried on the load
cable 11 rearward of the pivot handle 25. The retractor spring 52
is compressed between the handle 25 and cable loop 12, and operates
to normally urge the handle 25 and chock cables 21, 22 forward
thereby biasing the side chocks 14 and 16 in the anchor-expanding
position. The retractor spring 52 is preferably pre-loaded in the
anchor-expanding position at greater than 20% of its maximum
compression force. Preferably, the cable loop 12 is secured by a
duplex ferrule 53 and reinforced with a metal thimble (not shown).
An equipment tag 55 provides relevant product information.
[0035] Referring now specifically to FIG. 5, another conventional
expansible hole anchor which may be used in conjunction with the
pivot handle 25 constructed in accordance with an exemplary
embodiment of the present invention is illustrated, and shown
generally at reference numeral 100. As shown, the hole anchor 100
generally includes a load cable 112 having at a chock at a distal
end thereof. A center chock 114 is provided having an outer surface
113 and a cooperating outer chock assembly 115 is provided to
engage the center chock and to accommodate linear movement of the
cable 112 along a longitudinal axis "L" with respect thereto. For
example, the cable may be passed through the pivot handle 25
supporting the chock assembly 115.
[0036] The outer chock assembly 115 includes at least one outer
chock, such as the outer chock referenced as 116, and preferably
includes two or more outer chocks, such as the outer chocks
referenced as 116 and 117. Each outer chock is preferably attached
to the pivot handle 25 through a respective elongate control cable
or rod 122 that permits moving the outer chock upwardly along the
longitudinal axis with respect to the inner chock by pushing
upwardly on the handle 25.
[0037] As with the foregoing conventional hole anchor 10, the pivot
handle 25 may generally comprise a plurality of links 41, 42, 43,
44 and rockers 45, 46 (See FIG. 2) movably attached together on
opposite sides of the load cable 112 by fasteners 48.
Advantageously, when assembled about the load cable 112, the
rockers 45, 46 cooperate to allow kink-controlling movement of the
control cable 122 relative to the load cable 112. The handle 25
rocks or pivots when one control cable is in tension and the other
cable is in compression, thereby discouraging cable kinking or
excessive bending which may foul effective operation of the anchor
100.
[0038] In exemplary embodiments, the rockers 45, 46 include top and
bottom surfaces 56, 57 which are substantially planar. Further, the
rockers 45, 46 include a continuous side wall 58. In exemplary
embodiments, finger curves 59, 60 may be formed into the side wall
58 for facilitating retraction of the handle 25. The rockers 45, 46
may also be provided with a plurality of bores 61 for receiving the
fasteners 48.
[0039] The outer chocks 116 and 117 have inner surfaces 116a and
117a against which the outer surface 113 of the center chock 114
slides as a result of relative linear movement of the cable with
respect to the pivot handle 25. Particularly, when the pivot handle
25 is pushed downwardly along the axis "L" in the direction of the
arrow with respect to the cable, the outer chocks are forced
radially outwardly, to provide an expanded configuration of the
expansion bolt. When introduced into a hole, this outward expansion
of the outer chocks is resisted by the inner surface of the hole,
anchoring the expansion bolt in the hole. Conversely, when the
handle is pulled upwardly with respect to the cable, the outer
chocks are free to move inwardly toward the inner chock, or may be
biased toward the inner chock by the respective control cables or
rods 122, to provide a contracted configuration of the expansion
bolt. This permits removing the expansion bolt from the hole.
[0040] As illustrated, FIG. 5 shows a center chock 114 having a
convex outer surface 113 including convex portions 113a and 113b,
along with outer chocks 116 and 117 having complementary concave
inner surfaces. Preferably, the surfaces 113, 116a and 117a are
each rotationally symmetric about the longitudinal axis "L," and
more preferably still, the surfaces of the center and outer chocks
are complementarily frustoconically shaped. An example of
complementarily frustoconically shaped center and outer chocks is
shown in the Figures. Here, the center chock is shaped as a
frustrum so that the surface 113 is convex and the outer chock
surfaces 116a and 117a are concave and substantially conform to the
frustrum. The reverse geometry may also be employed for this
example, wherein the surfaces 116a and 117a are convex and shaped
as portions of frustrums, and the center chock surface 113 is
concave and substantially conforms to these portions. Moreover, the
surfaces 113, 116a and 117a may include only portions that are
complementarily frustoconical where desired.
[0041] The complementarily frustoconical shapes provide a preferred
means for ensuring intimate conformance between the respective
ramping surfaces of the center and outer chocks over a range of
relative linear movement therebetween, wherein the force exerted
between the chocks is distributed over a maximum surface area. This
increases reliability by decreasing stress and wear, as well as
increases hole-engaging strength by permitting the aforementioned
force to be maximized.
[0042] A loop 130 is provided at a proximal end of the cable 112
providing a hand-hold for a user of the expansion bolt 100, and a
means for moving the cable with respect to the handle 25. A
compression spring 132 is provided between the loop 130 and the
handle 25, to bias the device into its expanded configuration.
[0043] The expansion bolt 100 may also provide a "cleaning bushing"
134 through which the control cables or rods 122 are slidably
passed. The cleaning bushing 134 may be used to apply force to the
center chock 114 to loosen the grip applied by the expansion bolt
to the hole in which it is inserted, for removing the expansion
bolt after use.
[0044] The embodiments described above provide advantages over
conventional expansible hole anchors and associated methods of
manufacture. It will be apparent to those skilled in the art that
various modifications and variations can be made to the present
invention without departing from the spirit and scope of the
invention. Thus, it is intended that the present invention cover
the modifications and variations of this invention provided they
come within the scope of the appended claims and their equivalents.
Furthermore, the foregoing description of the preferred embodiment
of the invention and best mode for practicing the invention are
provided for the purpose of illustration only and not for the
purpose of limitation--the invention being defined by the
claims.
* * * * *