DETAILED ACTION
Response to Arguments
Applicant’s arguments, see Remarks, filed 8 July 2026, with respect to the rejection(s) of claim(s) 1-19 under 35 USC 103 have been fully considered and are persuasive. Therefore, the rejection has been withdrawn. However, upon further consideration, a new ground(s) of rejection is made in view of Knopp et al (US 20170016453 A1; also US 10,502,225 B2), Nakazawa (JP 2008309057 A), Wright et al (US 20180170147 A1) and/or Kawano (US 6,290,266 B1).
Claim Rejections - 35 USC § 103
The following is a quotation of 35 U.S.C. 103 which forms the basis for all obviousness rejections set forth in this Office action:
A patent for a claimed invention may not be obtained, notwithstanding that the claimed invention is not identically disclosed as set forth in section 102, if the differences between the claimed invention and the prior art are such that the claimed invention as a whole would have been obvious before the effective filing date of the claimed invention to a person having ordinary skill in the art to which the claimed invention pertains. Patentability shall not be negated by the manner in which the invention was made.
Claim(s) 1-11 is/are rejected under 35 U.S.C. 103 as being unpatentable over Knopp et al – hereafter Knopp – (US 20170016453 A1; also US 10,502,225 B2) in view of Nakazawa (JP 2008309057 A).
Regarding claim 1, Knopp teaches a road cleaning vehicle (Fig.1-8) comprising a debris collection arrangement (15) comprising a centrifugal fan assembly (21), wherein the centrifugal fan assembly comprises:
a fan casing (101) comprising a casing inlet (27) and a casing outlet (31), the casing inlet being in fluid communication with suction conduits (¶3) of the debris collection arrangement such that, in use, a suction force provided by the centrifugal fan assembly conveys debris along the suction conduits (¶40);
an impeller (23/24/25/26) mounted in the fan casing and rotatable about an axis of rotation for drawing fluid from the casing inlet and directing the fluid to the casing outlet (Fig.2-4).
Knopp does not explicitly teach the impeller comprising: a splitter wall extending outwardly from the axis of rotation to define first and second blade chambers extending from first and second faces of the splitter wall respectively, wherein the splitter wall comprises a splitter wall aperture; and a plurality of blades mounted in the first and second blade chambers, wherein the impeller is configured to, during rotation about the axis of rotation, direct fluid from the casing inlet through the first and second blade chambers to the casing outlet, the fluid being directed into the second blade chamber via the splitter wall aperture.
Nakazawa teaches an electric blower that is suitable for use in a vacuum cleaner and includes a multi-layer centrifugal fan impeller (machine translation page 1 “Technical-Field”; Fig.1/2/5/6). Nakazawa further teaches the impeller comprising: a splitter wall (23) extending outwardly from an axis of rotation (unlabeled dashed line) to define first and second blade chambers extending from first and second faces of the splitter wall respectively (Fig.1/2/5/6), wherein the splitter wall comprises a splitter wall aperture (Fig.6); and a plurality of blades (24/25) mounted in the first and second blade chambers, wherein the impeller is configured to, during rotation about the axis of rotation, direct fluid from a casing inlet (6a) through the first and second blade chambers to a casing outlet (defined by 31B on left side in Fig.6), the fluid being directed into the second blade chamber via the splitter wall aperture (Fig.6). The impeller configuration of Nakazawa allows providing a low noise impeller capable of a large blowing capacity (machine translation page 2 “Tech-Problem/Tech-Solution”).
It would have been obvious before the effective filing date of the claimed invention to a person having ordinary skill in the art to modify the road cleaning vehicle of Knopp by having the impeller comprising: a splitter wall extending outwardly from the axis of rotation to define first and second blade chambers extending from first and second faces of the splitter wall respectively, wherein the splitter wall comprises a splitter wall aperture; and a plurality of blades mounted in the first and second blade chambers, wherein the impeller is configured to, during rotation about the axis of rotation, direct fluid from the casing inlet through the first and second blade chambers to the casing outlet, the fluid being directed into the second blade chamber via the splitter wall aperture based on the teachings of Nakazawa because this would provide a low noise impeller capable of a large blowing capacity.
Regarding claim 2, Knopp and Nakazawa further teach the impeller further comprises a hub portion rotatably mounted to the fan casing (Nakazawa Fig.6, unlabeled; Knopp Fig.3, 26).
Regarding claim 3, Knopp and Nakazawa further teach the impeller further comprises: a first impeller wall (Nakazawa 21) comprising a first impeller wall aperture for directing fluid from the inlet into the first and second blade chambers and extending outwardly from the axis of rotation of the impeller (Nakazawa Fig.2/5/6); and a second impeller wall (Nakazawa 22) which is spaced apart from the first impeller wall and is adjacent to the hub portion (Nakazawa Fig.6), however do not explicitly teach the second impeller wall being parallel to the first impeller wall.
However, it is noted that applicant has not disclosed that having the second impeller wall being parallel to the first impeller wall results in an unpredicted result not seen in the prior art and it appears that the invention would perform equally well with the first and second walls as taught by Knopp and Nakazawa. Accordingly, absent persuasive evidence that the first and second walls configuration is functionally significant, the limitations above constitute a matter of choice of changes in shape and fail to patentably distinguish over the prior art. See MPEP 2144.04(IV)(b).
Regarding claim 4, Knopp and Nakazawa further teach the splitter wall is disposed between [[
Regarding claim 5, Knopp and Nakazawa further teach the plurality of blades extend continuously from the second impeller wall to the splitter wall (Nakazawa Fig.5/6).
Regarding claim 6, Knopp and Nakazawa further teach the plurality of blades extend continuously from the splitter wall to the first impeller wall (Nakazawa Fig.5/6).
Regarding claim 7, Knopp and Nakazawa further teach the splitter wall is located substantially midway between the first and second impeller walls (Nakazawa Fig.5/6).
Regarding claim 8, Knopp and Nakazawa further teach the first impeller wall aperture and splitter wall aperture are centred about the axis of rotation (Nakazawa Fig.6).
Regarding claim 9, Knopp and Nakazawa further teach the first impeller wall aperture is located in and/or adjacent to the casing inlet (Nakazawa Fig.6).
Regarding claim 10, Knopp and Nakazawa further teach the splitter wall aperture is located [[
Regarding claim 11, Knopp and Nakazawa further teach the impeller comprises an open outer impeller edge through which the first and second blade chambers are in direct fluid communication with the casing outlet (Nakazawa Fig.6).
Claim(s) 12-16 is/are rejected under 35 U.S.C. 103 as being unpatentable over Knopp and Nakazawa as applied to claim 1 above, and further in view of Wright et al – hereafter Wright – (US 20180170147 A1).
Regarding claim 12, Knopp and Nakazawa teach all the limitations of claim 1, see above, and further teach the splitter wall comprises a splitter wall main body from which the plurality of blades extend (Nakazawa Fig.5/6), however, do not explicitly teach a splitter wall guide wall extending from the splitter wall main body to the splitter wall aperture, wherein the splitter wall guide wall is configured to separate fluid flowing from the casing inlet into the first and second blade chambers.
Wright teaches a centrifugal fan assembly (Fig.5/7/8). The centrifugal fan assembly including an impeller (where 12 points to) and a fan casing (68), the fan casing further including a casing inlet (Fig.8, not labeled) and a casing outlet (Fig.8, 84/88), the impeller mounted in the fan casing (Fig.8) and drawing fluid from the casing inlet and directing the fluid to the casing outlet (Fig.8); a splitter wall (54) comprises a splitter wall main body (Fig.7, lower portion of 54) from which a plurality of blades extend (18/20), a splitter wall guide wall (Fig.7, upper portion of 54) extending from the splitter wall main body to a splitter wall aperture (67), wherein the splitter wall guide wall is configured to separate fluid flowing from the casing inlet into first and second blade chambers (¶42). The disclosed splitter wall shape/configuration allows decreasing fluid flow losses by providing the fluid flow a smoother transition when changing directions by 90 degrees, thereby improving the efficiency of a centrifugal fan assembly.
It would have been obvious before the effective filing date of the claimed invention to a person having ordinary skill in the art to further modify the road cleaning vehicle of Knopp and Nakazawa by having a splitter wall guide wall extending from the splitter wall main body to the splitter wall aperture, wherein the splitter wall guide wall is configured to separate fluid flowing from the casing inlet into the first and second blade chambers based on the teachings of Wright because this would allow decreasing fluid flow losses by providing the fluid flow a smoother transition when changing directions by 90 degrees, thereby improving the efficiency of a centrifugal fan assembly.
Regarding claim 13, Knopp, Nakazawa and Wright further teach the splitter wall guide wall is annular (Wright Fig.7).
Regarding claim 14, Knopp, Nakazawa and Wright further teach the splitter wall guide wall comprises:
a splitter wall ring portion (Wright Fig.7); and/or
a splitter wall curved portion (Wright Fig.7),
wherein:
the splitter wall ring portion is cylindrical and comprises an outer surface parallel to the axis of rotation (Wright Fig.7); and/or
the splitter wall curved portion comprises an outer surface which is concave (Wright Fig.7).
Regarding claim 15, Knopp, Nakazawa and Wright further teach the splitter wall ring portion extends from the splitter wall aperture to the splitter wall curved portion (Wright Fig.7), and/or
the splitter wall curved portion extends from the splitter wall ring portion to the splitter wall main body (Wright Fig.7).
Regarding claim 16, Knopp, Nakazawa and Wright further teach the plurality of blades extend to adjacent to the splitter wall guide wall (Wright Fig.7; not distant/nearby) [[]].
Claim(s) 17-19 is/are rejected under 35 U.S.C. 103 as being unpatentable over Knopp and Nakazawa as applied to claim 1 above, and further in view of Kawano (US 6,290,266 B1)
Regarding claim 17, Knopp and Nakazawa teach all the limitations of claim 1, see above, however, do not explicitly teach an inlet duct wherein the fan casing inlet is in fluid communication with the inlet duct.
Kawano teaches a suction elbow provided with guide vanes to be disposed in an inlet port of a pipe line, a duct, a range hood, a canopy hood, a suction floor of a clean room, etc. (column 1 line 5-9). Kawano further teaches an inlet duct wherein a fan casing inlet of a centrifugal fan is in fluid communication with the inlet duct (Fig.11(a)). The inlet duct/suction elbow configuration can achieve uniform distribution of sucked fluid velocity, small pressure loss, etc. (column 1 line 24-28).
It would have been obvious before the effective filing date of the claimed invention to a person having ordinary skill in the art to further modify the road cleaning vehicle of Knopp and Nakazawa by having an inlet duct wherein the fan casing inlet is in fluid communication with the inlet duct based on the teachings of Kawano because this could achieve uniform distribution of sucked fluid velocity, small pressure loss, etc..
Regarding claim 18, Knopp, Nakazawa and Kawano further teach a fluid guide vane disposed in the inlet duct and configured to direct fluid into the impeller in a direction parallel to the axis of rotation of the centrifugal fan assembly (Kawano Fig.11(a)).
Regarding claim 19, Knopp, Nakazawa and Kawano further teach the inlet duct is elongate along a duct longitudinal axis wherein the duct longitudinal axis is nonparallel to the axis of rotation of the centrifugal fan assembly (Kawano Fig.11(a)); and the fluid guide vane comprises a first vane portion extending parallel to the duct longitudinal axis from a first vane end and a second vane portion extending parallel to the axis of rotation from a second vane end (Kawano Fig.11(a)).
Conclusion
Applicant's amendment necessitated the new ground(s) of rejection presented in this Office action. Accordingly, THIS ACTION IS MADE FINAL. See MPEP § 706.07(a). Applicant is reminded of the extension of time policy as set forth in 37 CFR 1.136(a).
A shortened statutory period for reply to this final action is set to expire THREE MONTHS from the mailing date of this action. In the event a first reply is filed within TWO MONTHS of the mailing date of this final action and the advisory action is not mailed until after the end of the THREE-MONTH shortened statutory period, then the shortened statutory period will expire on the date the advisory action is mailed, and any nonprovisional extension fee (37 CFR 1.17(a)) pursuant to 37 CFR 1.136(a) will be calculated from the mailing date of the advisory action. In no event, however, will the statutory period for reply expire later than SIX MONTHS from the mailing date of this final action.
Any inquiry concerning this communication or earlier communications from the examiner should be directed to JUAN G FLORES whose telephone number is (571)272-3486. The examiner can normally be reached Monday - Friday, 8:30am - 5:30pm Pacific Time.
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If attempts to reach the examiner by telephone are unsuccessful, the examiner’s supervisor, Nathan E Wiehe can be reached at (571) 272-8648. The fax phone number for the organization where this application or proceeding is assigned is 571-273-8300.
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/JUAN G FLORES/Primary Examiner, Art Unit 3745
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