COMMISSIONER'S DECISION
OBVIOUSNESS: Dowel Anchoring Device
Use of a tapered spreader member to match with the interior walls of the
expanding dowel sleeve are known. Applicant has a smooth exterior cylindrical
surface in the expanding region to attain increased holding capacity over
the prior art ribbed or ridged dowel exterior surfaces. Evidente addressed
at the Hearing, and after the Final Action, demonstrated unexpected advantages
in the new dowel.
Final Action: Reversed.
**********
This decision deals with a request for review by the Commissioner of
Patents of the Examiner's Final Action dated January 12, 1976, on applica-
tion 152,192 (Class 85-5.3). The application was filed on September 20,
1972, and is entitled "Straddling Dowel." The Patent Appeal Board conducted
a Hearing on August 17, 1977, at which Mr. G. Ralston represented the
applicant.
This application relates to a straddling dowel-type anchoring device for se-
curing the inner end of a bolt in a hole in rock or concrete. The dowel
has a smooth outer surface and a conical inner surface having a corresponding
frustro-conical spreader element. A drawing of applicant's dowel is shown
below.
<IMG>
In the Final Action the examiner refused the application for failing to
set forth a patentable advance over the following references:
Canadian Patent 818,833 July 29,1969 Williams
Belgian Patent 564,476 Feb. 28,1958 Bergbaustahl
British Patent 1,186,035 Apr. 2, 1970 Fischer
United States Patents 1,000,715 Aug. 15,1911 Caywood
2,616,328 Nov. 5, 1952 Kingsmore
3,042,961 July 10,1962 Tieri
2,479,075 Aug. 16,1949 Martin
3,042,094 July 3, 1962 Liljeberg
The Williams patent relates to a mine roof rock anchoring device having a
threaded rod section, a generally cone-shaped expander in threaded engagement
with the rod section, and an expansible shell having an interior surface
normally bearing on the peripheral surface of said expander. Figures 1 and
6 of Williams are shown next:
<IMGS>
Caywood relates to an expansion wall plug adapted to be inserted in an
opening in a wall. Figure 1 from his disclosure is shown below.
<IMG>
Fischer and Bergbaustahl both relate to mounting bolts capable of anchorage
in a bore. The expanding section has peripheral serrations which grip the
surrounding cavity walls. Figure 4 of Fischer is shown.
(See formula 1)
Kingsmore discloses an anchoring device where the expansion of the inserted
portion is brought about by means of an inserted bolt. Figure 3(a) is repro-
duced next.
(See formula 2)
Liljeberg and Martin both relate to locking means for bolts wherein a threaded
receiving cavity utilizes a locking screw expanding means to retain the
hollow bolt in position.
The Tieri patent is for an ophthalmic mounting hinge using a soft deformable
expansion hinge pin tube.
In the Final Action the examiner gave the following reasons (inter alia) for
making the rejection:
...
Caywood discloses an expanding sleeve with a cylindrical middle
portion, a tapered enlarged head, and a bevelled forward end
on the outside, similar to applicant's device. The spreading
portion is grooved on the outside and has a square tapered
interior chamber to house an expander wedge, which features
differ from the applicant's device.
Kingsmore is suggestive of applicant's device in that the leading
end is rounded and thus reduced; the taper of the frustro-
conical bore of the sleeve and the taper of the expander member are
close, though not the same, and the middle portion of the sleeve
is cylindrical and smooth or provided with raised ridges as in
Figure 3a.
Tieri's sleeve, particularly as shown in Figure 2, is suggestive
of the applicant's sleeve in that it has a cylindrical middle
portion, a cylindrical leading end of reduced diameter, a tapered
enlarged head, and a tapered bore. However, Tieri's device is
not slotted and the expanding member is cylindrical, unlike
applicant's device.
Martin discloses screw locking means which comprises a tapered hole
in a screw member and a correspondingly tapered frustro-conical
expanding member, thus showing one of the main features of applicant's
device.
Liljeberg employs the feature mentioned above for a locking screw,
and radial slots in the expanding range of the screw.
Fischer discloses an anchor bolt having features common with the
applicant's device, such as an expanding sleeve member slotted in its
expanding range, and an expansion member with a conical point which
matches the conical restriction in the sleeve member.
The Bergbaustahl patent discloses a rock bolt having a frustro-
conical threaded end adapted to engage an expansion sleeve having a
similarly tapered threaded hole therein to co-act with said bolt
end. The sleeve has slots and the end faces thereof are chamfered.
Williams discloses a rock anchoring device which utilizes a cone
shaped expanding nut axially movable by a threaded rod, to expand
a slotted expansible shell having smooth cylindrical outer surface
and an axial bore tapered the same way as said cone. The disclosure
states, on page 1, paragraph 3:
"A problem has been encountered in cases where the rock
formation is soft or resilient, or when the bolt is
installed in concrete not yet fully cured."
...
In his response to the Final Action the applicant submitted an affidavit and
had this to say (in part):
In the Official Action of January 12th, 1976 top of page 2 the
Examiner summarizes Applicants' invention in six (6) lines.
This is an over-simplification of the invention. The invention has
the characteristics actually defined in the Patent Claim. To reduce
the Patent Claim which covers two (2) pages, to six (6) lines under-
mines the entire purpose of Patent Claim drafting and prosecution.
If it were possible to define a complex invention of this nature
in six (6) lines, then the work of Patent Agents, and Examiners
would be greatly simplified. Experience indicates that it is not
possible to simplify inventions to this point.
What possible purpose is there in drafting Patent Claims if they
are simply going to be ignored by the Examiner? If a Judge of the
Federal Court, in a Patent lawsuit were to proceed on this basis, his
reasons for judgment would be severely criticized on Appeal. It is also in-
structive to compare the Official Action of January 12th, 1976 top
of page 2 with the Official Action of May 7th, 1975 on the bottom
of page 1 to the middle of page 2. It would be noted that in the May 7th,
1975 Official Action, the Examiner has picked out ten (10) distinctive
features of the invention. In the more recent of January 12th, 1976 Official
Action, the Examiner has picked out only two (2).
In this respectful submission both Official Actions fall into the
error of over-simplification, and of ignoring the actual wording of
the Patent Claim. Of the two, however, the Official Action of May 7th,
1975 is certainly to be preferred.
...
Again, it is noted that these four references are only cited as dis-
closing the single feature of the matching taper. The other features
of Applicant's invention are clearly absent. It is this respectful
submission simply a matter of mosaicing of Patents to produce a composite
image of Applicant's invention. There is nowhere in any of these Patents
a teaching that a specific feature might be adapted from one Patent to
another. There is nowhere any suggestion that the feature of for example
the use of matching tapers is an improvement over earlier expanding
devices.
The newly cited Patents represent merely a selection made by the Examiner
for the purpose of supporting a pre-conceived argument. This is
totally the wrong approach to the question of Patentable subject matter.
It has been laid down over and over again that all of the prior art
must be reviewed to determine whether or not Patentable subject matter
exists in any particular invention as at the date when the invention
was made.
In this respectful submission, the Examiner has not done this in the
present Application. Having read Applicant's invention and thoroughly
understood it, he has simply gone to the shelves of the Patent Office
and selectively pulled out those Patents which he felt revealed the
individual features claimed in respect to Applicant's invention.
We have carefully studied the prosecution of this application, and considered
the extensive remarks made at the Hearing by Mr. Ralston.
The issue to be considered by the Board is whether or not the applicant has
made a patentable advance in the art over the cited references.
According to the applicant his device provides greatly increased pull-out
resistance over that of the prior art by:
1) matching the tapering angle of the interior of the expanding range
with the taper of the frustro-conical expansion member.
2) provision of a smooth cylindrical exterior surface in the expanding
range free of any ridges or ribs.
3) provision of a reduced diameter portion at the inner end of the expan-
sion range so that the inner end of the expansion range of the dowel
does not immediately come into contact with the rock until the expansion
member has been driven substantially into the expanding range of the
dowel.
Considering the first feature, a spreader member tapered to match with the
interior walls of the dowel sleeve, we find that to be a well known form to
accomplish dowel expansion. Dowel expansion in Fischer, Bergbaustahl, Caywood
and Kingsmore is attained in a similar manner.
The use of a smooth cylindrical exterior surface in the expanding range of the
plug was represented by the applicant as a major factor for increased holding
capacity. He argued that when the prior art uses ridges or ribs on the outer
expanding surface, this causes stress peaks which pulverize the hole wall
surface, and gives poorer holding capabilities than expected. Looking at
Williams we find his rock bolt anchor uses a smooth wall exterior shell to bind
against the bore hole surface, but Williams does not indicate this results
in superior holding power. It appears that Williams is concerned with the
prior art rock anchoring arrangements where the expander cone pulled through
the shell, and he devised an abutting shoulder in the shell to overcome that
problem. Granted, Williams discloses a different kind of anchor which is
expanded from the inside of the hole, with the expander moving to the hole
surface, as compared to what is done in this application in which the expander
moves away from the hole surface. Nevertheless the concept of a smooth cylindrical
exterior is illustrated.
The third feature stressed by the applicant is the reduced outer diameter
portion at the end of the expanding members. Tieri does disclose the use
of a reduced end diameter in his deformable cylindrical hinge member, but
this is in a rivetted hinge construction. We find no comparable reduced end
diameter in the remainder of the cited art.
An affidavit by Mr. Christian Giesler (an engineer with Hilti) was submitted
with the request for review. According to this affidavit, increased holding
power of the applicant's dowel results from the combination of the three re-
ferred to above. However there was no test data in the affidavit to support
the claims for increased holding power, and at the Hearing Mr. Ralston was
asked to submit this data. We have now received that information, and con-
sidered them in conjunction with the arguments presented at the Hearing and
the affidavit.
From the new data it appears that the average holding power of the applicant's
dowel, when compared to ribbed or ridged dowels, is 12 to 58% greater. From
the HILTI International Technical Information Bulletin, NR667-13, page 4,
Section 5.1, we reproduce the following chart to illustrate that point.
Size Average holding power *
HKD TZD
1/4 W (M6) 2100 lb (950 kp) 1320 lb (600 kp)
5/16 W (M8) 3000 lb (1350 kp) 2400 lb (1100 kp)
3/8 W (M10) 4300 lb (1950 kp) 3850 lb (1750 kp)
1/2 W (M12) 6400 lb (2900 kp) 5000 lb (2300 kp)
5/8 W (M16) 8000 lb (3650 kp) 7150 lb (3250 kp)
3/4 W (M20) 13000 lb (5900 kp) 10500 lb (4800 kp)
We conclude that the smooth external cylindrical surface with the matching
internal expanding surfaces and a reduced outer end portion of the cylinder
does produce increased holding power.
Claim 1 was amended in the response to the Final Action. This claim now
reads as follows:
A straddling dowel comprising a metallic sleeve having a lead-
ing end, which is inserted first into a bore hole formed to
receive the dowel, and a trailing end and forming a continuous
bore extending between the leading and trailing ends, said
sleeve having a spreading range extending rearwardly from its leading
end so that said sleeve can be spread radially outwardly and
anchored to the surface of the bore hole, said sleeve having slots
extending in the axial direction for a portion of its length from
the leading end and the axial length of said slots approximately
determining the axial length of the spreading range of said metallic
sleeve, and a spreader insertable into the continuous bore from
the trailing end and displaceable within the bore toward the leading
end for effecting the spreading action, wherein the improvement com-
prises that the surface of the continuous bore is tapered in a frusto-
conical shape for an axially extending portion thereof from the
leading end with said tapered surface diverging in the direction of
the trailing end and terminating adjacent to and spaced forwardly
of the trailing ends of said slots, the outer surface of said sleeve
in its spreading range from the leading end presenting a smooth
rounded surface in the circumferential direction, said spreader
having a frusto-conically shaped, axially extending portion extend-
ing rearwardly from its end which is located closer to the leading
end of the bore and which effects the spreading action within the
spreading range of said sleeve, the frusto-conically shaped portion
of said spreader having an angle of taper corresponding to the angle
of taper of the frusto-conically shaped tapered portion of said bore at
the trailing end thereof so that the frusto-conically shaped portion
of said spreader seats in closely fitting surface contact with the
correspondinbly shaped surface of said bore before it is driven
forwardly through the tapered surface of said bore whereby to ensure
even expansion of said sleeve in said spreading range to an enlarged
diameter which is essentially the same throughout said spreading
range, after driving in of said spreader, the axial length of the frusto-
conically shaped portion of said spreader being a fractional part of
the axial length of said tapered surface at the leading end of the
said bore so that prior to driving said spreader forwardly toward
the leading end for effecting the spreading action, its end closer to
the leading end of the bore is spaced rearwardly from the leading end,
the outer surface of said sleeve for an intermediate portion thereof
spaced from its leading and trailing ends and extending into the
spreading range has a cylindrically shaped surface, the forward end
of the outer surface of said sleeve between the leading end and the
cylindrically shaped surface of said intermediate portion being spaced
radially inwardly from a projection of the cylindrically shaped
surface and having a minimum diameter such that the leading end is not
widened to more than the diameter of the bore hole upon completion
of the spreading action and the axial length of the forward end of the
outer surface being not greater than the axial distance which the
end of said spreader located closer to the leading end of said sleeve
is spaced rearwardly from the leading end when it is in position in
contact with the tapered surface therein and before it is driven forward-
ly toward the leading end, and the plane of the surface of the projection
of the cylindrically shaped portion is, at its junction with the
cylindrically shaped portion disposed angularly relative to the
cylincrically shaped portion.
This claim includes the features discussed above. The new data with respect to
the increased pullout resistance was not before the Canadian examiner when he
made his assessment of patentability. In view of it we conclude that a certain
degree of unobviousness is present, and that amended claim 1 is clear of the
objection made in the Final Action. We consequently recommend that amended
claim 1 and dependent claims 2, 3 and 4 be accepted.
G.A. Asher
Chairman
Patent Appeal Board, Canada
Having reviewed the prosecution of this application, and considered the
amendment proposed, and the new test results provided by the applicant,
I direct that the application be returned to the examiner. Prosecution
should be resumed on the basis that the amendment overcomes the previous ob-
jections made by the examiner.
J.H.A. Gariepy
Commissioner of Patents
Agent for Applicant
G.A. Rolston
P.O. Box 2075
20 Eglinton Ave W.
Yonge-Eglinton Centre
Toronto, Ont.
M4R 1K8
Dated at Hull, Quebec
this 18th. day of November, 1977