Ex Parte McCordic et al

Patent Trial and Appeal BoardNov 25, 2013

11447488 (P.T.A.B. Nov. 25, 2013)

UNITED STATES PATENT AND TRADEMARK OFFICE ____________ BEFORE THE PATENT TRIAL AND APPEAL BOARD ____________ Ex parte CRAIG H. McCORDIC and LEO S. LUDWICK ____________ Appeal 2011-009770 Application 11/447,488 Technology Center 3700 ____________ Before STEFAN STAICOVICI, LYNNE H. BROWNE, and HYUN J. JUNG, Administrative Patent Judges. STAICOVICI, Administrative Patent Judge. DECISION ON APPEAL Appeal 2011-009770 Application 11/447,488 2 STATEMENT OF THE CASE Craig H. McCordic and Leo S. Ludwick (Appellants) appeal under 35 U.S.C. § 134 from the Examiner’s decision rejecting under 35 U.S.C. § 103(a) claims 1, 2, 4-10, and 12-17 as unpatentable over Bhatti (US 2003/0168205 A1, published Sep. 11, 2003) and Aoyagi (US 2001/0003309 A1, published Jun. 14, 2001); claims 19, 20, 22-28, and 30-33 as unpatentable over Bhatti, Aoyagi, and McCordic (US 6,903,931 B2, issued Jun. 7, 2005); claims 49-54 as unpatentable over Bhatti, Aoyagi, and Nelson (US 4,953,634, issued Sep. 4, 1990); and claims 56-72 as unpatentable over Bhatti, Aoyagi, Nelson, and McCordic. Claims 3, 11, 18, 21, 29, 34-48, 55, and 73-77 have been canceled. We have jurisdiction over this appeal under 35 U.S.C. § 6(b). INVENTION Appellants’ invention relates to a heat sink for controlling and reducing thermal gradients in a phased array radar system. Spec. 2, ll. 10- 11. Claim 1 is illustrative of the claimed invention and reads as follows: 1. A heat sink comprising: a fluid channel; and a cooling wall about the fluid channel including on one side thereof a cooling surface for cooling heat sources mounted thereon, the fluid channel having a constant area along its length in which a coolant flows to absorb heat from the cooling wall; a tapered body within the fluid channel to increase the coolant flow velocity and to compensate for a temperature rise in the coolant along the length of the fluid channel thereby reducing thermal gradients along the cooling surface. Appeal 2011-009770 Application 11/447,488 3 SUMMARY OF DECISION We AFFIRM-IN-PART. ANALYSIS The obviousness rejection based upon Bhatti and Aoyagi Appellants have not presented arguments for the patentability of claims 4, 6-10, and 12-17 apart from claim 1. See App. Br. 17-24. Therefore, in accordance with 37 C.F.R. § 41.37(c)(1)(vii) (2011), we select claim 1 as the representative claim to decide the appeal of the rejection of these claims, with claims 4, 6-10, and 12-17 standing or falling with claim 1. In view of Appellants’ arguments, we will address the rejection of claims 2 and 5 separately. The Examiner found that Bhatti discloses all the limitations of independent claim 1 with the exception of “the body in the fluid channel being tapered.” Ans. 3-4. The Examiner further found that Aoyagi discloses a heat exchanger including a tapered body 13B positioned within a fluid channel 14B. Ans. 4; see also Aoyagi, fig. 1(a). The Examiner concluded that “[i]t would have been obvious in view of Aoyagi et al to use a tapered insert in the heat exchanger of Bhatti et al, the motivation being to adjust the flow rate in various portions of the tube to improve the pattern of heat transfer.” Id. Claims 1, 4, 6-10, and 12-17 Appellants argue that: (1) Bhatti discloses a device that does not include a tapered body (but rather a twisted tape) (App. Br. 18-19) and which solves a different problem, namely increased heat rate transfer, Appeal 2011-009770 Application 11/447,488 4 “instead of compensation for cooling fluid temperature rise to reduce thermal gradients along a cooling surface” (App. Br. 18-19); (2) Bhatti and Aoyagi teach away from each other because Bhatti criticizes a serpentine heat exchanger, as that of Aoyagi, and Aoyagi criticizes a twisted spacer, as that of Bhatti (App. Br. 19-21; Reply Br. 1-2); (3) neither Bhatti nor Aoyagi discloses Appellants’ problem or solution to thermal gradients along a surface (App. Br. 21-23); and (4) the Examiner’s proposed modification of Bhatti’s heat exchanger with the tapered body of Aoyagi would change the principle of operation (Reply Br. 2-3) or destroy the functionality of Bhatti’s device (App. Br. 23-24). We are not persuaded by Appellants’ first argument because nonobviousness cannot be established by attacking the references individually when the rejection is predicated upon a combination of prior art disclosures. See In re Merck & Co. Inc., 800 F.2d 1091, 1097 (Fed. Cir. 1986). In this case, the Examiner’s rejection is based on the combined teachings of Bhatti and Aoyagi. We do not agree with Appellants that “it is error to simply substitute a different structure in another reference.” App. Br. 19. “[W]hen a patent claims a structure already known in the prior art that is altered by the mere substitution of one element for another known in the field, the combination must do more than yield a predictable result.” KSR Int’l Co. v. Teleflex, Inc., 550 U.S. 398, 416 (2007). Furthermore, the reason to modify a reference may often prompt a person of ordinary skill in the art to do what the inventor has done, but for a different purpose or to solve a different problem. It is not necessary that the prior art suggest the combination to achieve the same advantage or result discovered by an applicant. See, e.g., In re Kahn, 441 F.3d 977, 987 (Fed. Cir. 2006). Appeal 2011-009770 Application 11/447,488 5 As to Appellants’ second argument, we are not persuaded because simply that there are differences between two references is insufficient to establish that such references “teach away” from any combination thereof. In this case, although we appreciate the Appellant’s position that Bhatti criticizes a serpentine heat exchanger (see e.g., Bhatti, paras. [0004]-[0005]), nonetheless, we note that the Examiner is not proposing to modify the heat exchanger of Bhatti to include a serpentine pattern, but rather to substitute the tapered body of Aoyagi for the twisted tape of Bhatti. See Ans. 7. Appellants do not point to any passage in Bhatti that “criticize[s], discredit[s] or otherwise discourage[s]” the Examiner’s proposed modification of Bhatti. See In re Fulton, 391 F.3d 1195, 1201 (Fed. Cir. 2004). Furthermore, we do not see how Aoyagi teaches away from Bhatti because while Aoyagi criticizes a twisted spacer (see e.g., Aoyagi, para. [0024]), the Examiner’s proposed modification of Bhatti includes substituting the twisted tape with the tapered body of Aoyagi. Therefore, we do not agree with Appellants that either Bhatti or Aoyagi teach away from the Examiner’s proposed combination. In regards to Appellants’ third argument, “[t]he fact that appellant has recognized another advantage which would flow naturally from following the suggestion of the prior art cannot be the basis for patentability when the differences would otherwise be obvious.” See Ex Parte Obiaya, 227 USPQ 58, 60 (BPAI 1985). Here, although neither Bhatti nor Aoyagi explicitly discloses that the tapered body compensates for thermal gradients, nonetheless, because the modified heat exchanger of Bhatti and Aoyagi has the same structure as the heat sink of independent claim 1, it is reasonable to conclude that its operation is likewise the same. Appellants have not come Appeal 2011-009770 Application 11/447,488 6 forth with any persuasive evidence or technical reasoning to show otherwise. Moreover, we agree with the Examiner that Aoyagi discloses that, “providing a tapered insert in a flow tube reduces thermal gradients.” Ans. 8 (citing to Aoyagi, para. [0095]). Finally, with respect to Appellants’ fourth argument, we are not persuaded because Bhatti’s heat exchanger as modified by Aoyagi would still function as a heat exchanger. Appellants have not come forth with any persuasive evidence or technical reasoning to show why substituting the tapered body of Aoyagi for the twisted tape of Bhatti would prevent heat transfer from occurring between the cooling liquid traveling over the tapered body insert within the cooling channel 24 and heated electronic devices 38. See e.g., Bhatti, fig. 2. Although we appreciate that heat transfer efficiency may change, nonetheless, absolute predictability is not required, all that is required is a reasonable expectation of success. See In re O’Farrell, 853 F.2d 894, 903- 904 (Fed. Cir. 1988). Moreover, “a given course of action often has simultaneous advantages and disadvantages, and this does not necessarily obviate motivation to combine.” Winner Int'l Royalty Corp. v. Wang, 202 F.3d 1340, 1349 n.8 (Fed. Cir. 2000). Even assuming the proposed combination of the devices would change the heat transfer efficiency, as Appellants suggest, Appellants have not proffered evidence or a line of reasoning tending to show that such change would have discouraged a person of ordinary skill in the art from making the combination to attain other potential advantages. In conclusion, for the foregoing reasons, we sustain the rejection of claim 1, and dependent claims 4, 6-10, and 12-17 falling with claim 1, under 35 U.S.C. § 103(a) as unpatentable over Bhatti and Aoyagi. Appeal 2011-009770 Application 11/447,488 7 Claim 2 We are not persuaded by Appellants’ arguments because, once more, Appellants argue against the teachings of Bhatti and Aoyagi individually, whereas the Examiner’s rejection is based on the combined teachings of Bhatti and Aoyagi. See App. Br. 24-25. Moreover, we agree with Examiner that a tapered body placed within a cylindrical fluid channel, as shown in Figure 1(a) of Aoyagi, describes a “fluid channel being configured to form a tapered annulus along its length,” as called for by claim 2. Ans. 4. We thus likewise sustain the rejection of claim 2 over the combined teachings of Bhatti and Aoyagi. Claim 5 Appellants argue that the combined teachings of Aoyagi and Bhatti fail to disclose a tapered body and a cooling wall “selected to maintain a constant temperature cooling surface.” App. Br. 25. We are not persuaded by Appellants’ arguments because similar to Appellants’ situation where varying velocity of the cooling fluid results in varying the heat transfer coefficient h of cooling fluid, Aoyagi discloses that a higher velocity of the cooling fluid enhances the heat transfer coefficient. Compare Spec. 17, ll. 7- 16 with Aoyagi, para. [0095]. As such, because the modified heat exchanger of Bhatti and Aoyagi has the same structure as the heat sink of independent claim 1, it is reasonable to conclude that its operation is likewise the same. Therefore, we also sustain the rejection of claim 5 as unpatentable over Bhatti and Aoyagi. Appeal 2011-009770 Application 11/447,488 8 The obviousness rejection based upon Bhatti, Aoyagi, and McCordic Appellants have not presented arguments for the patentability of claims 22, 24-28, and 30-33 apart from claim 19. See App. Br. 26, 28. Therefore, we select claim 19 as the representative claim to decide the appeal of the rejection of these claims, with claims 22, 24-28, and 30-33 standing or falling with claim 19. In view of Appellants’ arguments, we will address the rejection of claims 20 and 23 separately. The Examiner found that Bhatti and Aoyagi disclose all the limitations of independent claim 19 with the exception of a plurality of “transmit/receive integrated multichannel modules mounted on the cooling wall,” which are taught by McCordic. Ans. 5. The Examiner concluded that “[i]t would have been obvious in view of McCordic . . . to cool a phased array radar system including transmit/receive integrated multi-channel modules using the heat sink of Bhatti et al in view of Aoyagi et al, the motivation being to prevent overheating of the devices.” Id. Claims 19, 22, 24-28, and 30-33 Appellants present similar arguments as set forth supra with respect to the rejection of claim 1. App. Br. 26-28. However, for the same reasons, we are not persuaded. Appellants further argue that, “hindsight analysis is manifest” because “[t]he conclusory statement of ‘motivation being to prevent overheating of the devices’ is not a substitute for evidence.” App. Br. 27. We are not persuaded by Appellants’ argument because the Examiner’s rejection is nothing more than “the mere application of a known technique to a piece of prior art ready for the improvement,” that is, applying the heat sink of Bhatti Appeal 2011-009770 Application 11/447,488 9 and Aoyagi to the plurality of transmit/receive integrated multichannel modules of McCordic. See KSR Int’l Co. v. Teleflex, Inc., 550 U.S. 398, 416 (2007). Unlike the Examiner, we do not consider the order in which prior art is applied in a rejection to be significant. See e.g., In re Bush, 296 F.2d 491, 496 (CCPA 1961). Appellants do not provide any evidence to show that modification of McCordic to provide the heat sink of Bhatti and Aoyagi would have been beyond the technical grasp of a person of ordinary skill in the art. We thus sustain the rejection of claim 19, and dependent claims 22, 24-28, and 30-33 standing with claim 19, under 35 U.S.C. § 103(a) as unpatentable over Bhatti, Aoyagi, and McCordic. Claims 20 and 23 Appellants present similar arguments as set forth supra with respect to the rejection of claims 2 and 5. App. Br. 28-30. Specifically, Appellants argue against the teachings of Bhatti, Aoyagi, and McCordic individually, whereas the Examiner’s rejection is based on the combined teachings of Bhatti, Aoyagi, and McCordic. Id. For the reasons set forth above, we also sustain the rejection of clams 20 and 23 over the combined teachings of Bhatti, Aoyagi, and McCordic. The obviousness rejection based upon Bhatti, Aoyagi, and Nelson The Examiner found that Bhatti and Aoyagi disclose all the limitations of independent claim 49 “with the exception of the wall having an increasing area in the direction of flow,” but that Nelson discloses a “heat sink . . . in which the wall . . . is tapered to vary its area in the direction of flow.” Ans. 6 (citing to Nelson, figs. 11 and 12). The Examiner concluded Appeal 2011-009770 Application 11/447,488 10 that it would have been obvious for a person of ordinary skill in the art to taper the wall of Bhatti and Aoyagi in the flow direction, as taught by Nelson, in order to “more easily adjust[] the rate of heat exchanger.” Id. The Examiner further opined that, “the direction of taper is considered to be a matter of engineering design choice based on the desired pattern of heat transfer.” Id. In response, Appellants argue that because Nelson specifically discloses decreasing the cross-sectional area in the flow direction, Nelson teaches away from a cooling wall increasing in area in the flow direction, as called for by independent claim 49. App. Br. 30-31; see also Reply Br. 3-4. We agree. Nelson specifically discloses that decreasing the cross-sectional area of a heat exchanger in the flow direction allows for increased volume of cooling fluid at a higher velocity to flow, which results in more uniform heat dissipation for cooling electronic components. Nelson, col. 3, l. 60 through col. 4, l. 33. “A reference may be said to teach away when a person of ordinary skill, upon [examining] the reference, would be discouraged from following the path set out in the reference, or would be led in a direction divergent from the path that was taken by the applicant.” In re Gurley, 27 F.3d 551, 553 (Fed. Cir. 1994). Here, modifying the taper in the cooling wall of Bhatti and Aoyagi to increase the wall area in the flow direction, as the Examiner proposes, would reduce the velocity of the cooling fluid, and thus reduce the volume of cooling fluid, which is in direct contrast to Nelson’s description. Thus, we do not agree with the Examiner’s position that modifying the taper in the cooling wall of Bhatti and Aoyagi to increase the wall area in the flow direction is a mere “engineering design choice.” Appeal 2011-009770 Application 11/447,488 11 See Ans. 6, 9. We thus find that Nelson would have discouraged one of ordinary skill in the art from modifying the taper in the cooling wall of Bhatti and Aoyagi to increase the wall area in the flow direction, as called for by independent claim 49. Accordingly, we do not sustain the rejection of claims 49-54 over the combined teachings of Bhatti, Aoyagi, and Nelson. The obviousness rejection based upon Bhatti, Aoyagi, McCordic, and Nelson The Examiner’s use of the teachings of McCordic does not remedy the deficiencies of Bhatti, Aoyagi, and Nelson as discussed supra. Therefore, for the reasons set forth above, we also do not sustain the rejection of claims 56-72 over the combined teachings of Bhatti, Aoyagi, McCordic, and Nelson. SUMMARY The Examiner’s decision is affirmed as to claims 1, 2, 4-10, 12-17, 19, 20, 22-28, and 30-33 and reversed as to claims 49-54 and 56-72. No time period for taking any subsequent action in connection with this appeal may be extended under 37 C.F.R. § 1.136(a)(1)(iv). AFFIRMED-IN-PART Klh