  United States Court of Appeals
      for the Federal Circuit
                ______________________

IN RE LUTZ BIEDERMANN AND JURGEN HARMS
            ______________________

                      2013-1080
                ______________________

    Appeal from the United States Patent and Trademark
Office, Patent Trial and Appeal Board in Application No.
10/306,057.
                 ______________________

               Decided: October 18, 2013
                ______________________

    LUKE DAUCHOT, Kirkland & Ellis, LLP, of Los Ange-
les, California, argued for appellant. With him on the
brief were NIMALKA R. WICKRAMASEKERA and BENJAMIN
A. HERBERT. Of counsel on the brief was MARK GARSCIA,
Christie, Parker & Hale, LLP, of Glendale, California.

    MONICA B. LATEEF, Associate Solicitor, United States
Patent and Trademark Office, of Alexandria, Virginia,
argued for appellee. With her on the brief were NATHAN
K. KELLEY, Deputy Solicitor, and AMY J. NELSON, Associ-
ate Solicitor.
                 ______________________

    Before MOORE, LINN, and O’MALLEY, Circuit Judges.
2                                    IN RE LUTZ BIEDERMANN




LINN, Circuit Judge.

    Lutz Biedermann and Jurgen Harms (collectively
“Biedermann”) appeal a decision of the Board of Patent
Appeals and Interferences (“Board”), now the Patent Trial
and Appeal Board, affirming the rejection of claims 32, 33,
35–37 37, 39, and 48 of U.S. Patent Application No.
10/306,057 (“’057 Application”) for obviousness, 35 U.S.C.
§ 103(a). Ex parte Biedermann, No. 2010-006113, Appli-
cation No. 10/306,057, 2012 WL 3561836 (B.P.A.I. Aug.
16, 2012) (Decision on Request for Rehearing) (“Decision
on Rehearing”); Ex parte Biedermann, No. 2010-006113,
Application No. 10/306,057, 2012 WL 1979400 (B.P.A.I.
May 30, 2012) (Decision on Appeal) (“Decision on Ap-
peal”). Because the Board issued new grounds of rejec-
tion, this court vacates and remands for further
proceedings.

                       I. BACKGROUND

                A. The Patent Application

    The invention in the ’057 Application, shown in the
below reproduced Figure 1, is generally directed to a bone
screw with a shank (1) and a holding portion with a U-
shaped cross-section (2) for a rod (100) that connects to
other bone screws. The two legs of the holding portion (4
and 5) have an inner thread (7) that cooperates with the
outer thread (8) of a locking element or screw (9) to hold
the rod securely in place. The two flat flanks of the inner
thread are at a 90˚ angle to the central axis of the holding
portion. This results in the thread having a substantially
rectangular cross-section. The flanks of the outer thread
of the locking element are likewise at a 90˚ angle to the
central axis of the locking element. These threads are
sometimes referred to as square threads. The crest of the
outer thread on the locking element is spaced from the
root of the inner thread on the holding portion. The ’057
IN RE LUTZ BIEDERMANN                                     3



Application describes these 90˚-oriented flat threads as
advantageously obviating the generation of outward
radial forces. This avoids splaying of the holding portion’s
legs and eliminates the need for an additional element
applied to the outside of the legs to avoid splaying. The
application also describes these threads as advantageous
because they are easy to produce.




    Representative Claim 32 of the ’057 Application re-
cites:

   32. A holding device comprising:

       a shank portion;

       a holding portion connected to the shank por-
   tion for holding a rod; and
4                                    IN RE LUTZ BIEDERMANN




        a locking element to lock the rod in the hold-
    ing portion;

        wherein the holding portion comprises a re-
    cess on one end having a U-shaped cross-section
    and two open legs for receiving the rod, and an
    inner thread on the open legs;

        wherein the locking element comprises an
    outer thread having two flanks, the outer thread
    cooperating with the inner thread, one of the two
    flanks of the outer thread facing the one end of
    the holding portion and the other of the two flanks
    of the outer thread facing away from the one end
    of the holding portion; and

        wherein the inner thread comprises two
    flanks, one of the two flanks of the inner thread
    facing the one end of the holding portion and the
    other of the two flanks of the inner thread facing
    away from the one end of the holding portion,
    each of the two flanks of the inner thread enclos-
    ing an angle of 90° with a central axis (M) of the
    holding portion;

        wherein a crest of the outer thread of the lock-
    ing element is spaced from a root of the inner
    thread when the locking element is tightened such
    that an axial force acts on the holding device to
    prevent the legs from splaying.

Decision on Appeal, at *1.

               B. The Examiner’s Rejection

    The examiner rejected claims 32, 33, 35–37, 39, and
48 of the ’057 Application as being unpatentable over U.S.
Patents No. 5,005,562 (“Cotrel”) and No. 4,846,614
IN RE LUTZ BIEDERMANN                                     5



(“Steinbock”) further in view of U.S. Patent No. 4,688,832
(“Ortloff”) under 35 U.S.C. § 103(a).

    Cotrel discloses a bone screw with a shank (1), a hold-
ing portion with internally threaded legs, and a locking
element or screw (8) to hold a rod (3), as generally shown
in Figure 3, reproduced below. Cotrel col. 2 ll. 14–34, col.




3 ll. 4–38.

    Steinbock discloses a machining arrangement for
moving heavy loads. In that context, it describes different
thread configurations as follows:

    [C]ertain threads are used to repeatedly move or
    translate machine parts against heavy loads. For
    these so-called translation threads a more effi-
    cient thread form is required. The most widely
    used thread forms for this purpose are the Square,
    the Acme and the Buttress. The Square thread is
    generally regarded as most efficient, but is diffi-
6                                    IN RE LUTZ BIEDERMANN




    cult to cut because the thread form provides paral-
    lel sides. It also cannot be adjusted to compensate
    for wear. The Acme form of thread does not suffer
    from the disadvantages of the Square thread form;
    it is stronger and only slightly less efficient. The
    Bustress [sic] thread form is used for translation
    of loads in one direction only. Because of its non-
    symmetrical form, it combines the high efficiency
    of the Square thread . . . with the ease of cutting
    and adjustment of the Acme thread.

Steinbock col. 1 ll. 25–41 (emphasis added).

    Completing the rejection, the examiner relied on the
Ortloff reference for its disclosure of gaps or clearances
between the crest of the outer thread and the root of the
inner thread. The examiner also noted that this feature
would be inherent in a device combining Cotrel and
Steinbock.

    The examiner considered Cotrel to disclose all ele-
ments of the claimed invention except for the orientation
of the two flanks of the inner thread enclosing an angle of
90° with respect to the central axis of the holding portion.
As for the missing thread configuration, the examiner
relied on Steinbock, stating:

        It is noted that there are a limited number of
    thread profile choices available to a person of or-
    dinary skill in the art for providing a threaded
    connection. In this regard it is noted that Stein-
    bock teaches different types of threads with a
    square thread being the most efficient for load
    transfer (col. 1, lines 14–44).

        Therefore, it would have been obvious to one
    of ordinary skill in the art at the time the inven-
    tion was made to have provided threads with a
IN RE LUTZ BIEDERMANN                                    7



   square profile on the Cotrel legs, as taught by
   Steinbock, for efficient load transfer.

Office Action at 2–3, Application No. 10/306,057 (Dec. 29,
2008) (“Final Rejection”) (emphasis added); accord Exam-
iner’s Answer at 3, Ex parte Biedermann, No. 2010-
006113, Application No. 10/306,057 (B.P.A.I. May 30,
2012) (Decision on Appeal) (“Examiner’s Answer”).

                C. The Board’s Decisions

    In analyzing the propriety of the examiner’s rejection,
the Board discussed the threads shown in Cotrel and
Steinbock and also made reference, for the first time, to
Erik Oberg et al., Machinery’s Handbook (Christopher J.
McCauley et al. eds., 26th ed. 2000) (“Machinery’s Hand-
book”). The Board did not reach Ortloff and instead relied
on the examiner’s alternative inherency rationale with
respect to the gap.

   With regards to the threads, Cotrel says,

   The female thread of the two flanks or branches of
   the body of the implant and the thread of the plug
   can be made with a saw-tooth pitch, in order to
   avoid the spreading of the two flanks by complete-
   ly eliminating the radial component of the load on
   screwing up.

Cotrel col. 2 ll. 54–58 (emphasis added) (reference num-
bers omitted). The Machinery’s Handbook at 1817 indi-
cates that a saw-tooth thread is a buttress thread. See
Decision on Appeal, at *2 & n.3.

   The Board specifically found that

   [t]he fact that Steinbock groups square, Acme,
   and buttress threadforms would at least suggest
8                                    IN RE LUTZ BIEDERMANN




    their interchangeability. . . . Cotrel already rec-
    ognized the desirability of eliminating the radial
    component of the load on screwing and the suita-
    bility of a threadform, the saw-tooth or buttress
    form, that may have typically been used for trans-
    lational applications to do so. Thus, one of ordi-
    nary skill in the art would have a reasonable
    expectation that a square threadform, which, like
    the buttress thread is also typically used for axial
    translation, would function in a manner similar to
    a saw-tooth or buttress thread to eliminate the
    radial component of a load on screwing, thereby
    discouraging spreading of Cotrel’s flanks . . . , or
    splaying.

         The Examiner’s discussion as to the benefits
    that would be realized by Cotrel from improved ef-
    ficiency is limited. However, this characteristic
    appears to be just one of several factors, including
    machinability, that one of ordinary skill in the art
    would consider when selecting an appropriate
    threadform. . . . Though not referred to as a saw-
    tooth thread, [another reference], discussed in
    [Biedermann’s] Specification, appears to have
    similar characteristics to a saw-tooth and, accord-
    ing to [Biedermann], is difficult to produce—a
    problem [Biedermann] perceive[s] as mitigated by
    use of a square thread.

Id. at *2 (footnotes omitted) (citations omitted) (internal
quotation marks omitted). The Board thus affirmed the
examiner’s rejection.

    Biedermann requested rehearing, arguing that the
Board issued a new ground of rejection by relying on
“interchangeability” instead of “efficiency” and by refer-
ring to the Machinery’s Handbook, and additionally
arguing that the Board failed to consider the negative
IN RE LUTZ BIEDERMANN                                      9



teachings of Steinbock that relate to machinability. The
Board denied Biedermann’s request. The Board ex-
plained that “by ‘interchangability’ [sic] we meant that
the record demonstrates a likelihood that the threadforms
grouped by Steinbock could successfully be substituted
into Cotrel’s device. . . . Cotrel clearly expresses the
desirability of minimizing or eliminating the radial com-
ponent of load on screwing up.” Decision on Rehearing, at
*1. The Board further explained that “Steinbock’s group-
ing was regarded as a suggestion that, in addition to a
saw-tooth or buttress thread, good results may also be
achieved using an Acme or Square thread which share
certain characteristics that Cotrel recognized as im-
portant—the ability to eliminate or minimize radial
loading.” Id. at *2. The Board acknowledged that “[t]he
Examiner may have specifically proposed in the Office
Action to select a thread ‘for the most efficient load trans-
fer’ as opposed to one that minimized or eliminated radial
loading due to contact or interference.” Id. at *1 (empha-
sis added).

    As to the Machinery’s Handbook, the Board found
that “[t]he only fact detrimental to [Biedermann] based
upon this extrinsic evidence was confirming that the ‘saw-
tooth’ and ‘buttress’ threading described by Cotrel and
Steinbock, respectively, referred to essentially the same
thing,” of which Biedermann was “already aware.” Id.
The Board asserted that it did not change the thrust of
the rejection and instead “merely relied upon a reference
akin to a technical dictionary to confirm the meaning of
terms used in the references before us.” Id.

    Commenting on machinability, the Board noted that
the square thread was beneficial, but that its “drawback,
according to Steinbock, is difficulty cutting. The record,
when considered as a whole, does not support [Bieder-
mann’s] position that difficulty cutting square threads
10                                    IN RE LUTZ BIEDERMANN




would lead one away from their use if one desired . . .
[their] benefit.” Id. at *2.

    The Board denied reconsideration and again affirmed
the examiner’s rejection. Biedermann appeals. This court
has jurisdiction under 28 U.S.C. § 1295(a)(4)(A).

                       II. DISCUSSION

                   A. Standard of Review

    “Whether the Board relied on a new ground of rejec-
tion is a legal question that we review de novo.” In re
Stepan Co., 660 F.3d 1341, 1343 (Fed. Cir. 2011).

                        B. Analysis

    “Obviousness is a question of law based on underlying
findings of fact.” In re Kubin, 561 F.3d 1351, 1355 (Fed.
Cir. 2009). The underlying factual inquiries are: (1) “‘the
scope and content of the prior art,’” (2) the “‘differences
between the prior art and the claims at issue,’” (3) “‘the
level of ordinary skill in the pertinent art,’” and (4) “‘sec-
ondary considerations’” of nonobviousness. KSR Int’l Co.
v. Teleflex Inc., 550 U.S. 398, 406 (2007) (quoting Graham
v. John Deere Co. of Kan. City, 383 U.S. 1, 17–18 (1966)).
In assessing the obviousness of patent claims,

     [o]ften, it will be necessary for a court to look to
     interrelated teachings of multiple patents . . . in
     order to determine whether there was an appar-
     ent reason to combine the known elements in the
     fashion claimed by the patent at issue. To facili-
     tate review, this analysis should be made explicit.
     See In re Kahn, 441 F. 3d 977, 988 (CA Fed. 2006)
     (“[R]ejections on obviousness grounds cannot be
     sustained by mere conclusory statements; instead,
     there must be some articulated reasoning with
IN RE LUTZ BIEDERMANN                                  11



   some rational underpinning to support the legal
   conclusion of obviousness”).

KSR, 550 U.S. at 418 (alteration in internal quotation in
original). The articulated reasoning and factual under-
pinnings of an examiner’s rejection are, thus, essential
elements of any stated ground of rejection to which appli-
cants are entitled to notice and a fair opportunity to
respond.

     The central question in the present case is whether
the Board and the examiner properly relied on the same
articulated reasoning and factual underpinnings in reject-
ing Biedermann’s claims or whether the Board made new
findings and adopted different reasons to support a new
ground of rejection, thus depriving Biedermann of both
notice and an opportunity to respond.

    Biedermann argues that the Board did not rely on the
examiner’s efficient load transfer rationale to combine
Cotrel and Steinbock, and instead issued a new ground of
rejection by adopting a rationale based on newly found
facts relating to the avoidance of splaying. Biedermann
argues that the examiner did not find facts about Cotrel’s
threads or splaying and that the Board found the thread-
form of Cotrel interchangeable with the square thread-
form based on the new findings that: (a) Steinbock
grouped square and buttress threads; (b) the Machinery’s
Handbook associated saw-tooth and buttress threads; (c)
Cotrel’s threads were saw-tooth threads that avoid splay-
ing; and (d) square threads would similarly avoid splay-
ing. Biedermann also argues that the Board was critical
of the examiner’s rationale and relied on the Machinery’s
Handbook in finding a new reason to combine Cotrel and
Steinbock. Moreover, Biedermann argues that the mere
fact that the Board was responding to Biedermann’s
arguments does not obviate the fact that the Board issued
a new ground of rejection. Finally, Biedermann argues
12                                   IN RE LUTZ BIEDERMANN




that the Board newly and erroneously concluded that one
of ordinary skill would have reason to substitute square
threads for the saw-tooth threads in Cotrel because they
are easier to machine.

     The government argues that the Board did not issue a
new ground of rejection, that Biedermann had the oppor-
tunity to respond to the thrust of the rejection, and that
the Board relied on the examiner’s efficient load transfer
rationale and simply provided a more detailed explana-
tion. The government also argues that the Board did not
find new facts regarding Cotrel’s thread type, its effect on
splaying, or its relationship or similarity to other thread
types because the Board was responding to or relying on
Biedermann’s arguments or statements. The government
also argues that the Board only used the Machinery’s
Handbook as a technical dictionary. Finally, the govern-
ment argues that the Board did not change the thrust of
the rejection by referring to machinability because it was
listing additional benefits in response to one of Bieder-
mann’s arguments.

    The Patent and Trademark Office (“PTO”) is subject
to the Administrative Procedure Act (“APA”). See Dickin-
son v. Zurko, 527 U.S. 150, 154 (1999). Under the APA,
the PTO “must assure that an applicant’s petition is fully
and fairly treated at the administrative level.” In re
Kumar, 418 F.3d 1361, 1367 (Fed. Cir. 2005). The APA
requires the PTO “to provide prior notice to the applicant
of all ‘matters of fact and law asserted’ prior to an appeal
hearing before the Board.” Stepan, 660 F.3d at 1345
(quoting 5 U.S.C. § 554(b)(3)); see also In re Leithem, 661
F.3d 1316, 1319 (Fed. Cir. 2011) (“Under the [APA], an
applicant for a patent who appeals a rejection to the
Board is entitled to notice of the factual and legal bases
upon which the rejection was based.” (citing 5 U.S.C.
§ 554(b)(3))). Accordingly, the PTO’s rules “provide that
when the Board relies upon a new ground of rejection not
IN RE LUTZ BIEDERMANN                                      13



relied upon by the examiner, the applicant is entitled to
reopen prosecution or to request a rehearing.” Leithem,
661 F.3d at 1319 (citing 37 C.F.R. § 41.50(b)). These
rights “ensure that the Board can fulfill its notice obliga-
tion to the applicant during prosecution.” Stepan, 660
F.3d at 1344. Failure to follow these procedures requires
this court to vacate the Board’s decision. See Rambus Inc.
v. Rea, __ F.3d __, No. 2012-1634, 2013 WL 5312505, at *7
(Fed. Cir. Sept. 24, 2013).

    When considering whether the Board issued a new
ground of rejection, the “ultimate criterion of whether a
rejection is considered ‘new’ in a decision by the Board is
whether applicants have had fair opportunity to react to
the thrust of the rejection.” Leithem, 661 F.3d at 1319
(internal quotation marks and alteration marks omitted).
While “[t]he Board need not recite and agree with the
examiner’s rejection in haec verba to avoid issuing a new
ground of rejection,”

   [m]ere reliance on the same statutory basis and
   the same prior art references, alone, is insufficient
   to avoid making a new ground of rejection when
   the Board relies on new facts and rationales not
   previously raised to the applicant by the examin-
   er. This court’s predecessor long acknowledged
   the right of the Board to make additional findings
   of fact based upon the Board’s own knowledge and
   experience to fill in the gaps that might exist in
   the examiner’s evidentiary showing. But the
   Board’s power to do so is construed narrowly and
   when reliance upon such facts changes the thrust
   of the rejection, the Board’s action does everything
   but cry out for an opportunity to respond.

Id. (citations omitted) (internal quotation marks omitted).
A new ground of rejection, however, generally will not be
found based on the Board “further explain[ing] the exam-
14                                  IN RE LUTZ BIEDERMANN




iner’s rejection” or the Board’s thoroughness in respond-
ing to an applicant’s argument. See In re Jung, 637 F.3d
1356, 1364–65 (Fed. Cir. 2011).

     In Leithem, this court concluded that the Board issued
a new ground of rejection. See 661 F.3d at 1317. The
patent claim at issue in Leithem covered a diaper contain-
ing wood “fluff pulp” prepared by a certain method. Id.
The examiner rejected the claim as obvious over a combi-
nation including the “Novak” reference, which the exam-
iner explained disclosed “a method of making fluff pulp.”
Id. (internal quotation marks omitted). Leithem argued
and the Board “agreed” that Novak “d[id] not disclose a
fluffed pulp,” but the Board sustained the examiner’s
rejection and found that Novak disclosed “a pulp which
may be fluffed.” Id. at 1317–18 (internal quotation marks
omitted). This court concluded that “[t]he thrust of the
Board’s rejection changes when, as here, it finds facts not
found by the examiner regarding the differences between
the prior art and the claimed invention, and these facts
are the principal evidence upon which the Board’s rejec-
tion was based.” Id. at 1320 (citation omitted).

     Here, the examiner’s reasoning in support of combin-
ing the square thread of Steinbock with the device of
Cotrel was that there were a limited number of threads
that could be used and that a square thread was the most
efficient. While the examiner in the Examiner’s Answer
made a passing reference to splaying in relation to the
gaps between the inner and outer threads, the examiner’s
rejection neither relied upon nor even noted the avoidance
of splaying as a factor. The Board, on the other hand,
found new facts as the basis for concluding that the
combination of Cotrel and Steinbock would have been
obvious: that Cotrel teaches avoiding splaying with saw-
tooth threads; that saw-tooth threads are buttress
threads; that Steinbock groups together the square
threads and buttress threads; and that square threads
IN RE LUTZ BIEDERMANN                                     15



avoid splaying. The principal reason the examiner com-
bined the references was the efficiency of a square thread.
The principal reason the Board affirmed the combination
of the references was the avoidance of splaying by using
square threads. These are different grounds and form the
bases or underpinnings of different rejections. Even the
Board itself recognized that efficiency and avoiding splay-
ing were different. Decision on Rehearing, at *1. This is
analogous to Leithem in which the Board distinguished
fluffed pulp from pulp that could be fluffed. See 661 F.3d
at 1318, 1320.

    The government’s argument that the Board was
providing additional details for the examiner’s reasoning,
rather than changing the thrust of the rejection, is not
persuasive. The thrust of the rejection changed when the
Board found a new factual basis for the reason to com-
bine. The Board went beyond filling in gaps in the exam-
iner’s reasoning because it is not clear that the examiner’s
reasoning survived in the Board’s rejection. Unlike Jung,
there is no indication that the Board was merely explain-
ing the examiner’s rejection. See 637 F.3d at 1365. The
present case is similar to Rambus, 2013 WL 5312505, at
*7, in which the examiner made an erroneous finding in
support of a combination of references and the Board
made new, alternative findings to support the combina-
tion. “While the Board’s findings may ultimately be
correct, we will not affirm a Board rejection, like this one,
which essentially provides a new motivation to combine
the references.” Id.

    The government asserts that the Board was merely
responding to Biedermann’s arguments rather than
issuing a new ground of rejection. A new ground of rejec-
tion is not negated by the fact that the Board is respond-
ing to an appellant’s argument. See Stepan, 660 F.3d at
1345 (“[T]he mere fortuity that Stepan addressed the
validity of the Declaration on its own, without the issue
16                                    IN RE LUTZ BIEDERMANN




being raised by the examiner, does not permit the Board
to reject the Declaration as ineffective without designat-
ing its decision as a new ground of rejection.”); Leithem,
661 F.3d at 1317, 1320 (concluding that the Board issued
a new ground of rejection despite the fact that the Board
“agreed with Leithem” that Novak did not teach a fluffed
pulp).

    As to the Machinery’s Handbook, the citation of a new
reference will be a new ground of rejection in some in-
stances:

         Ordinarily, citation by the board of a new ref-
     erence, such as the dictionary in this case, and re-
     liance thereon to support a rejection, will be
     considered as tantamount to the assertion of a
     new ground of rejection. This will not be the case,
     however, where such a reference is a standard
     work, cited only to support a fact judicially noticed
     and . . . the fact so noticed plays a minor role,
     serving only to fill in the gaps which might exist
     in the evidentiary showing made by the Examiner
     to support a particular ground for rejection.

In re Boon, 439 F.2d 724, 727-28 (CCPA 1971) (citation
omitted) (internal quotation marks omitted).

     In this case, the Board used the Machinery’s Hand-
book to associate buttress and saw-tooth threads. There
is no clear gap in the examiner’s reasoning that would be
filled by the association between saw-tooth and buttress
threads, particularly since Cotrel’s threads appear irrele-
vant to the examiner’s reasoning. Rather, the association
between saw-tooth and buttress threads played an im-
portant role, not a minor role, in the Board’s new reason-
ing by providing the link to associate Cotrel’s threads
with one of the threadforms grouped in Steinbock. The
IN RE LUTZ BIEDERMANN                                   17



Machinery’s Handbook, thus, was used as part of the new
ground of rejection.

     The Board’s treatment of machinability in the Deci-
sion on Appeal was also a new ground of rejection. The
Board treated machinability as another factor, in addition
to efficiency, that one of ordinary skill would consider in
selecting a threadform, making it part of the reason to
combine the references. See Decision on Appeal, at *2.
Identifying machinability as an additional reason to
combine does not mean that it is not a new ground of
rejection. See In re Waymouth, 486 F.2d 1058, 1061
(CCPA 1973) (“To attempt to deny appellants an oppor-
tunity to provide a different and appropriate response to
the board’s rejection by saying that the board merely
advanced ‘an additional reason’ for affirming the examin-
er begs the question and does not satisfy the administra-
tive due process . . . .”), modified, 489 F.2d 1297 (CCPA
1974). There is no apparent connection between machin-
ability and the examiner’s reason to combine based on
efficiency.

                     III. CONCLUSION

   For the foregoing reasons, this court vacates the
Board’s decision and remands for further proceedings.

             VACATED AND REMANDED
