Ex Parte Auth

Board of Patent Appeals and Interferences

Aug 14, 2009

11008343 (B.P.A.I. Aug. 14, 2009)

UNITED STATES PATENT AND TRADEMARK OFFICE
____________

BEFORE THE BOARD OF PATENT APPEALS
AND INTERFERENCES
____________

Ex parte STEFAN AUTH
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Appeal 2009-000750
Application 11/008,343
Technology Center 3700
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Decided: August 14, 2009
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Before DONALD E. ADAMS, ERIC GRIMES, and
RICHARD M. LEBOVITZ, Administrative Patent Judges.

LEBOVITZ, Administrative Patent Judge.

DECISION ON APPEAL
This is a decision on the Patent Applicant’s appeal from the Patent
Examiner’s rejection of claims 1-13. Jurisdiction for this appeal is under 35
U.S.C. § 6(b). We reverse.

Appeal 2009-000750
Application 11/008,343

STATEMENT OF THE CASE
The claims are directed to a self-drilling bone screw, alone, and in
combination with a bone plate. The self-drilling screw is designed to be
rapidly screwed into a bone or bone fragment while avoiding bending or
breaking of the screw tip (Spec. 2:1-3).
Claims 1-13 are appealed and stand rejected by the Examiner as
follows:
• Claims 1, 2, 4, 7, 8, and 10 under 35 U.S.C. § 102(b) as anticipated
by Bechtel (U.S. Published Application No. 2003/0210970 A1, Nov. 13,
2003) (Ans. 3);
• Claims 3, 5, 6, and 9 under 35 U.S.C. § 103(a) as obvious in view of
Bechtel (Ans. 4); and
• Claims 11-13 under 35 U.S.C. § 103(a) as obvious in view of
Niiranen (U.S. Pat. No. 6,692,498 B1, Feb. 17, 2004), Bechtel, and
Whitmore (U.S. Published Application No. 2005/0021036 A1, Jan. 27,
2005) (Ans. 4).
Claims 1, 10, and 11 are representative and read as follows:

1. A self-drilling bone screw comprising:
a head; and
a shank extending from the head and having a thread with a pitch of
approximately 0.7 to 1.0 mm, the shank having a tip with a tip angle selected
such that a thread flank of a first flight of the thread adjacent to the tip is
arranged at a distance of approximately 0.2 to 0.5 mm from the tip.

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10. A self-drilling bone screw comprising:
a head;
a shank extending from the head to a distal end, the shank having a
thread with a pitch of approximately 0.7 to 1.0 mm; and
a tip disposed at the distal end of the shank with a tip angle of
approximately 34 to 43º.

11. An implant system comprising:
a self-drilling bone screw having a head and a shank extending from
the head, the shank having a thread with a pitch of approximately 0.7 to 1.0
mm and a tip with a tip angle selected such that a thread flank of a first flight
of the thread adjacent to the tip is arranged at a distance of approximately
0.2 to 0.5 mm from the tip; and
a bone plate defining a bore and a recess disposed about the bore, the
head of the bone screw adapted to rest in the recess and the shank of the
bone screw adapted to penetrate the bore.

ANTICIPATION BY BECHTEL
Claims 1, 2, 4, 7, 8, and 10 stand rejected under 35 U.S.C. § 102(b) as
anticipated by Bechtel.
Statement of the Issues
Claim 1
Independent claim 1 is directed to a self-drilling screw with a shank
“having a thread with a pitch of approximately 0.7 to 1.0 mm” and a thread
flank starting “at a distance of approximately 0.2 to 0.5 mm from the tip”
(also known as the thread start distance). The Examiner contends that these
limitations are met by the screw described in the Bechtel patent. Appellant
contends that the Examiner erred in finding that Bechtel described a screw
with the claimed thread pitch and thread start distance. The issue is whether
Appellant established that the Examiner erred in these findings.

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Claim 10
Independent claim 10 is directed to a self-drilling screw with a shank
“having a thread with a pitch of approximately 0.7 to 1.0 mm” and a tip at
the distal end of the shank “with a tip angle of approximately 34 to 43°.”
The Examiner contends that these limitations are met by the screw described
in the Bechtel patent. Appellant contends that the Examiner erred in finding
that Bechtel described a screw with the claimed thread pitch and tip angle.
The issue is whether Appellant established that the Examiner erred in these
findings.
Findings of Fact (“FF”)
The Bechtel patent
1. Bechtel describes a thread-forming screw that forms threads as the screw
advances into a body (¶ 3).
2. The thread start “S” occurs at a precise location relative to the distal tip of
the shank (¶¶ 31 & 40).
3. Bechtel describes how S is calculated for a screw and discloses S values
from 0.038 inches to 0.084 inches for exemplary screws (¶¶ 47 & 53).
4. 0.038 inches corresponds to 0.96 mm (Ans. 7); 0.084 inches corresponds
to 2.13 mm (App. Br. 10).
5. Bechtel states that, in preferred embodiments, all screws are provided
with 18 threads per axial inch of shaft to simplify manufacture (¶ 29) and
that a screw with “a common number of threads per inch of screw length for
various screw sizes” is an “advantage” of its “invention” (¶ 16).
6. 18 threads per axial inch corresponds to a thread pitch of 1.4 mm (Ans. 8;
App. Br. 8).
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7. Bechtel describes exemplary screws with S values that range from 0.038-
0.084 inch and which have a thread pitch of 18 threads per axial inch (¶¶ 42,
53 & 57).
8. Bechtel describes the taper angle from the shaft to the shaft tip to be 30º
for all its screws (¶¶ 41 & 51).
9. A standard sized #4 screw is described by Bechtel to have 24 threads per
inch or a thread pitch of 1.06 mm (¶ 6; Ans. 6).

The Specification
10. The only tip to thread start distance range disclosed in the Specification
is “approximately 0.2 to 0.5 mm” (Spec. 2:8-11), which is the same as the
range recited in claim 1.
11. The only example of a thread start distance is of a screw with a thread
start at “approximately 0.32 mm from the screw tip.” (Spec. 4:30-32; 5:7-8.)

Analysis
Claim 1
It is undisputed that Bechtel describes a screw with a thread start
distance from 0.96 to 2.13 mm from the shank tip (FF2-4). The Examiner
contends that “the axial distance from the tip of the screw to the thread start
value of 0.96 millimeters is imprecise but fairly close to or approximately
0.2 millimeters to 0.5 millimeters” range recited in claim 1 (Ans. 7). Based
on this finding, the Examiner concluded that Bechtel met the claim
limitation of a screw with “a thread flank of a first flight of the thread
adjacent to the tip is arranged at a distance of approximately 0.2 to 0.5 mm
from the tip.”
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Application 11/008,343

The Examiner’s interpretation of “approximately 0.2 to 0.5 from the
tip” to read on the 0.96 mm tip to thread start distance described in the
Bechtel patent is not reasonable. The claimed thread start range spans 0.3
mm; this is the only range described in the Specification and there are no
values disclosed outside of it (FF10-11; App. Br. 9). The difference between
the claimed endpoint of 0.5 mm and Bechtel’s value of 0.96 mm is 0.46 mm,
which is greater than 0.3 mm covered by the entire claimed range (0.5 mm-
0.2 mm). It is not reasonable to interpret “approximately” to read on a value
that is almost double the endpoint of the claimed range (0.96 mm/0.5 mm =
1.92) and whose difference (0.96 mm-0.5 mm = 0.46 mm) between it and
the range endpoint is greater than the breadth of the entire claimed range
(0.3 mm). For this reason, we reverse the rejection of claim 1, and
dependent claims 2, 4, 7, and 8, which incorporate all the limitations of
claim 1.

Claim 10
Claim 10 is to a self-drilling bone screw with a shank “having a thread
with a pitch of approximately 0.7 to 1.0 mm” and a tip at the distal end of
the shank “with a tip angle of approximately 34 to 43°.”
Appellant does not dispute that Bechtel describes a screw which meets
the tip angle recited in claim 10. The Examiner found that Bechtel disclosed
in its background section a standard sized No. 4 screw with a thread pitch of
1.06 mm (Ans. 6; FF9), meeting the corresponding limitation of claim 10.
Appellant contends that the Examiner erred in finding the thread pitch
limitation met by Bechtel. According to Appellant, the pitch of the prior art
No. 4 screw is 1.06 mm, but the pitch of Bechtel’s improved screw is 1.4
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Application 11/008,343

mm (App. Br. 8). Therefore, Appellant concludes Bechtel “fails to disclose
a screw that combines a thread pitch of approximately 0.7 to 1.0 mm with a
tip having a tip angle of from 34 to 43º” (App. Br. 11).
The Examiner has not provided sufficient evidence that Bechtel
describes a screw that meets the limitations of claim 10. Bechtel describes
its invention as a screw with a thread pitch of 1.4 mm (FF5-7), which falls
outside the claimed upper limit of 1.0 mm. The Examiner’s rationale for
finding the upper claimed limit to have been met by Bechtel is that Bechtel
describes a prior art screw with the thread pitch of 1.06 mm (FF9) – a value
that is about 1 mm as recited in claim 1.
However, the Examiner has not provided evidence that the prior art
thread pitch of 1.06 mm was combined with the tip angle of 30º, a necessary
finding to establish that all elements of claim 10 are described in Bechtel.
Bechtel repeatedly states that its invention is a screw with a common
number of threads for all screw sizes (FF5). This common number is stated
to be 18 threads per inch or a thread pitch of 1.4 mm (FF5 & 7). In the
examples, Bechtel refers to a screw of “the present design” (Bechtel, at ¶¶
54-56) which would reasonably be understood to mean the 1.4 mm thread
pitch in light of statements made before (id. at ¶¶ 16, 29, and 42) and after
(id. at ¶ 57) characterizing this pitch as standard for its invention.
Accordingly, since not all elements of claim 10 are described in the
Bechtel patent, the rejection of claim 10 is reversed.

OBVIOUSNESS IN VIEW OF BECHTEL
Claims 3, 5, 6, and 9 stand rejected under 35 U.S.C. § 103(a) as
obvious in view of Bechtel.
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Claims 3, 5, 6, and 9 depend directly or indirectly on claim 1. The
Examiner argued that limitations introduced in claims 3, 5, 6, and 9 were
obvious in view of Bechtel’s teachings. However, Examiner did not provide
any reasoning or evidence as to why it would have been obvious to modify
Bechtel’s screw to have made a screw with a thread flank starting “at a
distance of approximately 0.2 to 0.5 mm from the tip” as recited in claim 1,
which we concluded is not taught by Bechtel. As claims 3, 5, 6, and 9
incorporate all the limitations in claim 1, we are therefore compelled to
reverse the rejection.

OBVIOUSNESS IN VIEW OF NIIRANEN, BECHTEL, AND WHITMORE
Claims 11-13 stand rejected under 35 U.S.C. § 103(a) as obvious in
view of Niiranen, Bechtel, and Whitmore.
The Examiner stated that it would have been obvious
to construct the system of Niiranen with a bone screw being self
drilling, having a thread pitch of 1.05mm, and an axial distance
from the tip of the screw to the start of the threads of
approximately 0.451 to 0.5863 mm in view of Whitmore and
Bechtel in order to eliminate the step of drilling a preliminary
guide hole, to use a screw that is easier to manufacture, and to
use a screw that has a optimized relationship between the
insertion torque requirements and the strip-out resistance.
(Ans. 6.)
The Whitmore patent
12. Whitmore describes a self-drilling, self-tapping bone screw that has dual
lead threads which form a spiral path from the cutting tip (¶¶ 18-19).

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Analysis
Claim 11 is to a bone plate and a bone screw with a shank “having a
thread with a pitch of approximately 0.7 to 1.0 mm” and a thread flank
starting “at a distance of approximately 0.2 to 0.5 mm from the tip.” Claim
13 is to a method of using a bone plate and bone screw with the same
limitations as in claim 11. The Examiner has not provided sufficient
evidence to establish that it would have been obvious to have made a screw
with the claimed limitations.
The absence of the 0.2 to 0.5 mm thread start limitation from the
Bechtel screw has been addressed above. See supra at pp. 5-6. Whitmore
describes a self-drilling, self-tapping bone screw with threads which form a
spiral path from the cutting tip (FF12). The Examiner has not provided a
reason as to why it would have been obvious to modify Whitmore or
Bechtel’s screw to meet the claimed thread start distance. The values of
0.451 to 0.5863 mm cited by the Examiner in support of the rejection appear
to be based on Appellant’s own Specification1, not the cited prior art.

Conclusions of Law
The Examiner erred in finding that Bechtel described or suggested a
screw with a thread flank starting “at a distance of approximately 0.2 to 0.5
mm from the tip” as recited in claims 1, 11, and 13.
The Examiner erred in finding that Bechtel described a screw with a
shank “having a thread with a pitch of approximately 0.7 to 1.0 mm” and a

1 “When the factor of 0.451 is multiplied by the range diameter given in the
specification [,] the range for the axial distance from the tip of the screw to
the start of the threads is approximately 0.451 to 0.586 millimeters.” (Ans.
3.)
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Appeal 2009-000750
Application 11/008,343

tip at the distal end of the shank “with a tip angle of approximately 34 to
43°” as recited in claim 10.

Summary
The anticipation rejection of claims 1, 2, 4, 7, 8, and 10 and the
obviousness rejections of claims 3, 5, 6, 9, and 11-13 are reversed.

REVERSED

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