Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
5 ~
BACKGROUND OF THE INVENTION
The present invention relates to a convenient and efficient drive
unit for the installation of threaded studs with resinous materials into
: holes formed in concrete, mansonry, rock or the like. A device for
containing the resinous materials is disclosed in the United States
sReissue Patent to Schuermann et al, No. 25,869. Threaded studs
secured by resinous materials are frequently employed in lining
mine openings and tunnels, making safe ove:rhanging rock walls and
for structural engineering purposes such as reinforcing foundations,
securing machines on such foundations or to provide facilities for mount-
10ing or attaching other parts on or to their outer ends such as to formhooks. The resin employed has a small shrinkage upon hardening
and is placed into the drill hole and will penetrate the surrounding
crevaces, fissures or cracks in the rock or cementatious material
surrounding the drill hole and fill it to secure the stud.
-
.- '911~
:~ .
.
-
1 165~55
DESCRIPTION OF THE PRIOR ART
_
In the ReisOEue Patent mentioned above, the anchor is fixed into
concrete, masonry, rock or the like by placing a frangible ampule
of resinous material into a drilled hole and then twisting a threaded
5 stud into the hole with a rotary drill. The threaded stud breaks the
ampule and forces the resinous material to flow around the threads.
A tool commonly used for inserting the stud includes three pieces of
equipment. One is an elongated hex-nut which is threaded onto an
end of the stud and the second is a slotted-head cap screw which is
10 adapted to be threaded into the hex-nut and to receive a third piece
which is a shanl~ that can be connected to a drill chuck. Because
such drive units are formed of several parts, they are expensive to
manufacture and parts can become lost during operation. The shank
wears out from time to time and falls from the cap screw fairly easily.
15 Moreover the engagement of the stud and the hex-nut frequently be-
comes very tight so that after installation of l:he stud it is extremely
difficult to separate the two.
1 ~5~
--3--
SUMMARY OF ~HE I~VE~IO~
According to the present invention we have developed
- a drive unit to insert a threaded stud having a predetermined
diameter into concrete, masonry, rock or the like. The
drive unit includes a shank having a central portion with a
generally polygonal cross section and being adapted to
receive a wrench. One end of the shank has a generally
circular cross section which is adapted to be inserted into
the chuck of a drill and the other end is threaded. The
diameter of the threaded end is substantially the same as
the diameter of the stud so that a conventional nut can be
threaded onto both to lock the two together for insertion.
In the preferred emb~diment the thread of the
threaded portion of the drive unit has an unde~cut on the
abutment side, that is, some of the flank of the thread is
removed to reduce friction and 1:o enable the conventional
nut to be easily removed after the stud has been inserted.
In a further aspect of the invention, the distal end of the
threaded portion of th~ drive unit is convexly shaped so as
to reduce the amount of engagement between the drive unit
and the threaded stud when the two are joined together and
engage each other.
.
-3a-
According to a further broad aspect of the present
invention there is provided a drive unit for a threaded stud
of predetermined diameter and thread pitch that is to be
rotatably driven through the action of a rotary drill into
a frangible ampule placed within masonry, concrete, rock
or the like~ ~The drive unit comprises a nut having a uniform
thread diameter and a uniform thread pitch for threadably
engaging the threads o~ the stud. The nut is adapted to
receive a furst wrench. A shank of unitary construction
is provided and has a central portion with-a generally poly-
gonal cross-section and is adapted to recelve a second wrench.
The shank fùrther has a first unitary cylindrical extension,
disposed at one end of the central portion, for insertion
into the chuck of a rotary drill. The shank still further
has a second unitary extension with a threaded portion
disposed at the other end of the central portion. The
diameter and thread pitch of the threaded portion is substan-
tially the same as the predetermined diameter and thread
pitch of the stud where the nut has the same predetermined
thread pitch and diameter and is threaded onto both the stud
and the threaded portion on the secondary extension of the
shank so as to lock the two to~ether prior to the stud being
driven into a medium within the frangible ampule by rotation
of the rotary drill.~ The stud is ultimately detached -from
the shank by engaging the central portion with the second
~ ~5~S~
--4--
wrench and the nut with the first wrench and twisting the
wrenches in opposite directions so as to disconnect the
nut from the threaded portion of the second unitary e~tension
without disturbing the inserted condition of the stud
within the frangible ampule.
BRIEF DESCRIPTION OF T~E DRAWINGS
Figure 1 is an elevational view, partially in cross-
section, of the drive unit attached at one end to a threaded
stud and at the other end to the chuck of a rotary drill.
The threaded stud is shown partially inserted in a drilled
hole with the end abutting ayainst an ampule of resinous
ma+~erial.
Figure 2 is a perspective view of -the drive unit shown
in Fig. 1.
~6~15~
--5--
1 DESCRIPTION OF THE PREFERRED E~1BODIMENTS
Referring now to Figures 1 and 2, the drive unit 1 includes a generally
cylindrical shank having a central portion 2 with a generally polygonal and
preferably hexagonal cross section so as to receive a conventional wrench.
The upper end 3 of the drive unit 1 is adapted to receive a conventional
chuck 12 of a rotary drill (not shown). The lower end 4 of the drive unit 1
is threaded with threads of the same pitch as the stud 5 to be inserted into
concrete, masonry~ rock or the like 14. Preferably, the threads 4 are
undercut, that is a portion of the flank is removed so that the contact
between the threads of the nut 6 and the threads 4 of the drive unit 1
shifts from a surface engagement to more closely approximate a line
engagement. In that way the drive unit can be loosely fit with a nut 6 that
is used to attach it to the threaded stud 5 and reduce friction between
threads to avoid disturbance of the anchor when the drive unit 1 is being
removed after installation.
The nut ~ is of conventional shape and design and attaches the drive
unit 1 to the threaded stud 5. As shown, the threaded stud 5 may have a
chamfered end 7 to enable it to readil~y break ampule 8 with the resin. A
washer 9 or other structural member may be disposed about the stud 5 dur;ng
insertion if desired. As show, the ampule 8 and the stud 5 are disposed in
a hole 10 drilled in concrete, masonry, rock or the like 14. The hole 10 is
carefully drilled so that it will have a diameter approximating the outside
diameter o~ the stud 5 and also be of a predetermined depth.
As more clearly shown in Figure 2, the distal end 11 of the threaded
,
31 1IB5~55
--6--
1 portion 4 is generally convex (relative to the axis of the drive unit) so as
to reduce friction with the end of the stud 5 when the two are joined
together. As seen in phantom lines in Figure 1, the convex end 11 abuts the
flat surface of the stud 5 when the two are joined together with nut 6.
To seat the threaded stud 5 into a drilled hole 10 with a resin, we
drop the ampule 8 into the hole 10. The hole 10 has been drilled to
appropriate depth and corresponds to the diameter of the stud 5. All dust
is blown out. The threaded stud 5 has a predetermined thread pitch and is
attached to the threaded portion 4 (having d similar predetermined thread
pitch) of the drive unit 1 by nut 6. The nut 6 of course has the same
predetermined thread patch as the threaded stud 5 and the threaded portion
4. The shank 3 is inserted into the chuck 12 and the chuck is tightened.
The nut 6 is threaded to half its thickness onto the threaded portion ~ of
the drive unit 1 and the stud 5 is then threaded into nut 6. The chamFered
end 7 of the stud 5 is forced against the ampule 8 to break it and the drill
is switched on engaging the drive unit to transfer rotary and percussive
action to the stud 5 which is driven down to the bottom of the hole
resulting in a thorough mixing of the chemicals around the stud. When the
stud reaches the bottom of the hole 10 the drill is switched off. Two
2Q wrenches are then used, one being placed around the nut 6 and the other
being placed around the central portion 2 o~ the drive unit 1 and they are
twisted in opposite directions. The twisting disconnects the nut 6 from the
drive unit 1 without disturbing the positioning of the stud 5. The stud 5
is allowed to remain undisturbed for a specified curing time and devices to
,~ .
l lB5~
--7--
1 be attached are placed on the stud 5. The bolt is thus securely fixed in aposition in the bore 10 by chemical bond and the attachments can be securely
fixed to the base 14.
- It is to be pointed out that although the upper portion 3 is shown
having a cylindrical cross section that can easily fit into a drill chuck,
this portion can be made with an "A" taper to allow it to be inserted in a
number of different size drills or it is possible to attach the chuck
permanently to the shank 3.
It is apparent that modifications and changes can be made within the
spirit and scope of the present invention but it is our intention, however,
only to be limited by the appended claims.
2Q
.,
, '
,
: 25
'' .
.
