Notice of Pre-AIA or AIA Status
The present application, filed on or after March 16, 2013, is being examined under the first inventor to file provisions of the AIA . This office action is in response to the amendment filed on 6/12/2026 in which claims 1-6, 10-16, 20 are pending
Claim Rejections - 35 USC § 102
The following is a quotation of the appropriate paragraphs of 35 U.S.C. 102 that form the basis for the rejections under this section made in this Office action:
A person shall be entitled to a patent unless –
(a)(1) the claimed invention was patented, described in a printed publication, or in public use, on sale, or otherwise available to the public before the effective filing date of the claimed invention.
Claims 1, 10, 11 and 20 are rejected under 35 U.S.C. 102(a)(1) as being anticipated by Kullberg (U.S. Publication 2021/0037704).
In regards to claim 1, Kullberg discloses a trimmer comprising: a motor (4); a trimmer head (trimmer head 1) disposed on a connecting member (pole 6) and including a trimmer line spool (spool 5); a user interface (one or more buttons 12) disposed on the connecting member (6), wherein the user interface is configured to operate the trimmer head; a sensor (sensor) configured to determine a length of a trimmer line (3) extending from the trimmer head
“As an alternative, or in addition, the trimmer 13 may comprise a sensor configured to detect a length of the trimmer line 3, wherein the trimmer 13 is configured to initiate feed of trimmer line 3 when the length is below a threshold value” paragraph [0063])
wherein the trimmer line (3) is disposed on the trimmer line spool (5); and, an auto advance mechanism (“wherein the trimmer 13 is configured to initiate feed of trimmer line 3” paragraph [0063]) configured to extend the trimmer line extending from the trimmer head based on feedback from the sensor (inherent from paragraph [0063]);
wherein the auto advance mechanism comprises a centrifugal clutch (39) operably connected to the trimmer line spool (5); wherein the centrifugal clutch is in an operable connection with the motor (4) of the trimmer to selectively engage the trimmer line spool to advance the trimmer line based on a rotational speed of the centrifugal clutch;
and wherein the motor (4) causes the centrifugal clutch to rotate past a threshold speed (“by accelerating, or decelerating, the trimmer head 1 at a higher rate than during normal operation”; paragraph [0063]) when the length of the trimmer line falls below a predetermined threshold value to advance the trimmer line to a desired length (“to initiate feed of trimmer line” paragraph [0063]), and wherein the motor reduces the rotational speed of the centrifugal clutch below the threshold speed when the trimmer line advances to the desired length.
(“If the trimmer head 1 is rotating at a rotational speed below the threshold rotational speed, and trimmer head 1 is subjected to a change in rotational speed via the interface 2 at a higher rate than the threshold rate, no trimmer line will be fed because the inner body 1c is free to rotate relative the spring holding member 38. Thus, due to the centrifugal clutch 39, the automatic feed mechanism 7 will release the trimmer line when the trimmer head 1 rotates at rotational speed above the threshold rotational speed and when the trimmer head 1 is subjected to a change in rotational speed, via the interface 2, at a higher rate than the threshold rate. Thereby, an unintended release of trimmer line can be avoided at lower rotational speeds.”; paragraph [0072]
In regards to claim 10, the modified device of Kullberg discloses wherein the auto advance mechanism automatically extends the trimmer line (45) when the length falls below a predetermined threshold value.
“As an alternative, or in addition, the trimmer 13 may comprise a sensor configured to detect a length of the trimmer line 3, wherein the trimmer 13 is configured to initiate feed of trimmer line 3 when the length is below a threshold value” paragraph [0063])
In regards to claim 11, Kullberg discloses a method for auto advancing a trimmer line of a trimmer, the method comprising: determining a length of the trimmer line (3) extending from a trimmer head (1) and disposed on a trimmer line spool (“the trimmer 13 may comprise a sensor configured to detect a length of the trimmer line 3” paragraph [0063]);
comparing the length to a predetermined threshold value (“wherein the trimmer 13 is configured to initiate feed of trimmer line 3 when the length is below a threshold value” paragraph [0063]);
and, automatically advancing the trimmer line if the length falls below the predetermined threshold value (“configured to initiate feed of trimmer line 3 when the length is below a threshold value” paragraph [0063]);
wherein automatically advancing the trimmer line (3) comprises selectively engaging the trimmer line spool with a centrifugal clutch (39) operably coupled to a motor (4) of the trimmer to advance the trimmer line based on a rotational speed of the centrifugal clutch (see paragraphs 0063; 0072-0073);
and wherein the motor (4) causes the centrifugal clutch (39) to rotate past a threshold speed (“by accelerating, or decelerating, the trimmer head 1 at a higher rate than during normal operation”; paragraph [0063]) when the length of the trimmer line falls below a predetermined threshold value to advance the trimmer line to a desired length (“to initiate feed of trimmer line” paragraph [0063]), and wherein the motor reduces the rotational speed of the centrifugal clutch below the threshold speed when the trimmer line advances to the desired length.
(“If the trimmer head 1 is rotating at a rotational speed below the threshold rotational speed, and trimmer head 1 is subjected to a change in rotational speed via the interface 2 at a higher rate than the threshold rate, no trimmer line will be fed because the inner body 1c is free to rotate relative the spring holding member 38. Thus, due to the centrifugal clutch 39, the automatic feed mechanism 7 will release the trimmer line when the trimmer head 1 rotates at rotational speed above the threshold rotational speed and when the trimmer head 1 is subjected to a change in rotational speed, via the interface 2, at a higher rate than the threshold rate. Thereby, an unintended release of trimmer line can be avoided at lower rotational speeds.”; paragraph [0072]
In regards to claim 20, Kullberg discloses wherein: when the motor (4) causes the centrifugal clutch (39) to rotate past a threshold speed, the centrifugal clutch (39) engages the trimmer line spool (via locking device 46) such that it rotates and advances the trimmer line (see paragraphs 0063 and 0072-0073 reproduced below); and when the motor (4) reduces the rotational speed of the centrifugal clutch (39) below the threshold speed, the centrifugal clutch disengages the trimmer line spool such that the trimmer line spool no longer rotates to advance the trimmer line (see paragraphs [0072-73 reproduced below)
(“the automatic feed mechanism 7 will perform a release of trimmer line when the trimmer head 1 is subjected to a rate of change in rotational speed, via the interface 2, at a higher rate than what is obtained during normal operation of a trimmer. The trimmer 13 illustrated in FIG. 1, may be configured to initiate a feed of trimmer line 3 by accelerating, or decelerating, the trimmer head 1 at a higher rate than during normal operation.” Paragraph [0063]
(“If the trimmer head 1 is subjected to a change in rotational speed, via the interface 2, at a higher rate than the threshold rate, for example an abrupt deceleration, the inner body 1c and the spring holding member 38 will rotate relative the housing 1a, 1b. As a result, the locking lever 23 moves from the first radial position to the second radial position, and the trimmer line spool 5′ is free to rotate. If the trimmer head 1 is rotating at a rotational speed below the threshold rotational speed, and trimmer head 1 is subjected to a change in rotational speed via the interface 2 at a higher rate than the threshold rate, no trimmer line will be fed because the inner body 1c is free to rotate relative the spring holding member 38.” paragraphs [see paragraphs 0072-0073])
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.
Claims 2-3, 5, 12-13, and 16 are rejected under 35 U.S.C. 103 as being unpatentable over Kullberg (U.S. Publication 2021/0037704) in view of Zha et al. (U.S. Publication 2019/0269070), herein referred to as Zha.
In regards to claim 2 and 12, the modified device of Kullberg discloses a trimmer including a sensor configured to detect when the trimmer line falls below a threshold value so that the length of the trimmer line can be automatically increased. However, Kullberg does not disclose the specific type of sensor such that it is a draw sensor or a Hall sensor or the location of the sensor to perform this detection. Zha teaches a string trimmer with a release mechanism capable of releasing the trimmer line to increase the trimmer line extending out of the spool and further discloses a calculation unit configured to determine to calculate usage and the remaining amount of trimmer line. Zha further teaches that the smart release mechanism includes a detection module and a controller, wherein the detection module may include a Hall sensor, a color recognition sensor or vibration sensor. Accordingly, it would have been obvious to one of ordinary skill in the art at the time of the invention to employ one of the sensors taught by Zha, such as a Hall sensor, color recognition sensors, or vibration sensor, in the trimmer of Kullberg in order to detect when the trimmer line falls below the threshold value.
In regards to claims 3 and 13, the modified device of Kullberg discloses wherein the sensor comprises a Hall sensor (Zha paragraph [0063,0068])
In regards to claim 5 and 16, the modified device of Kullberg discloses wherein the Hall sensor is disposed on a cutter ( on trimmer 13, as modified by Zha; “a Hall sensor is disposed on the line container and detects the magnetism of the trimmer line” Zha paragraph [0063,0068]).
Claims 3-4 and 15 are rejected under 35 U.S.C. 103 as being unpatentable over Kullberg (U.S. Publication 2021/0037704) in view of Zha et al. (U.S. Publication 2019/0269070), herein referred to as Zha. In regards to claims 3, 4 and 15, Kullberg discloses guard 10 at least partially enclosing trimmer head 1. Kullberg, however, does not expressly disclose a Hall sensor disposed on the guard 10. Zha teaches a detection module comprising a Hall sensor configured to detect a magnetic signal from a magnetic trimmer line and a controller configured to initiate release of additional trimmer line when the Hall sensor detects no magnetic signal from the trimmer line. (see paragraph [0029]. It would have been obvious to one of ordinary skill in the art to dispose Zha’s Hall sensor on guard 10 of Kullberg because guard 10 provides a stationary and protected mounting location adjacent to the trimmer line, thereby permitting the Hall sensor to detect the presence of absence of the magnetic trimmer line as taught by Zha. Ther proposed modification would predicably permit detection of insufficient trimmer line length and initiation of additional line feeding.
Claim 6 and 14 are rejected under 35 U.S.C. 103 as being unpatentable over
Kullberg (U.S. Publication 2021/0037704) in view of Zha et al. (U.S. Publication 2019/0269070), herein referred to as Zha and in further view of Legrand (U.S. Patent 6,630,226).
In regards to claim 6 and 14, the modified device of Kullberg does not disclose wherein the trimmer line comprises ferrous particles embedded in a plastic line. Attention is further directed to the Legrand, which discloses a trimmer cutting line including a monofilament core coated with a granular layer comprising inorganic particles. Legrand further teaches that the coating may include metallic particles such as zinc, iron or aluminum. The composite cutting line is disclosed as providing improved cutting performance, reduced operating nose, and breakage at the eyelet of the rotary head (see abstract). It would have been obvious to one of ordinary skill int eh art to incorporate iron particles taught by Legrand into the plastic trimmer line of Kullberg, as modified by Zha, because the iron particles would render the trimmer line magnetically detectable by Zha’s Hall sensor, thereby permitting detection of the presence or absence of the trimmer line as taught by Zha. Legreand further teaches that its particle containing composite line provides improved cutting performance, reduced operating noise, and reduced breakage at the trimmer head eyelet.
Response to Arguments
Applicant's arguments filed 06/12/2026 have been fully considered but they are not persuasive. The Applicant argues that Kullberg does not disclose that the Kullberg sensor detection automatically causes the power source 4 to accelerate or decelerate the trimmer 13, nor that the motor reduces the rotational speed of the centrifugal clutch below the threshold speed when the trimmer line advances to the desired length. Kullberg expressly discloses that the trimmer may include a sensor configured to detect the length of the trimmer line and that the trimmer initiates feeding when the detected length is below a threshold value. Kullberg further teaches that feeding is initiated by accelerating or decelerating the trimmer head at a rate exceeding a threshold rate of change (see paragraph [0063]). Thus, contrary to Applicant’s assertion, Kullberg relates the sensor detected insufficient line length to the disclosed motor-controlled change in rotation speed that initiates line feeding.
Kullberg also teaches that the centrifugal clutch engages above a threshold rotational speed, that abrupt deceleration releases the trimmer line spool and that the spool rotates a predetermined angle thereby advancing a predetermined length of trimmer line. See paragraphs [0032], [0071] and [0072]. Kullberg further teaches that no trimmer line will be fed when the rotational speed is below the threshold rotational speed. Accordingly, Kullberg teaches advancing a predetermined- i.e. desired-length of trimmer line through the disclosed acceleration/deceleration sequence and reducing the rotational speed below the threshold to prevent further feeding. The claim does not require a separate sensor or feedback determination that the desired length has been reached.
Applicant’s arguments regarding claims 2, 12 are not persuasive. Claim 2 requires the draw sensor to be “configured to determine how much of the trimmer line has been drawn from the trimmer line spool”, but does not require the draw sensor to directly monitor physical movement of the trimmer line or rotation of the spool. The examples cited by Applicant from paragraph [0044] of the specification are permissive embodiments introduced by the term “may” and are not limitations recited in claim 2. Zha teaches that calculation unit 50 receives and counts release signals that each release signal causes the release mechanism, to operate once and advances a corresponding quantity of trimmer line, and that the calculation unit 50 calculates the used length and/or the remaining length of the trimmer line based on the number of release signals (see paragraphs [0004] and [0049]. Thus, regardless of whether a release signal originates from operation of a start switch or a manual release button, calculation unit 50 uses signals corresponding to discrete line advancement events to determine the cumulative amount of trimmer line drawn from the spool. Accordingly, Zha’s calculation unit satisfies the claimed drawn sensor under the broadest reasonable interpretation of the claim. Applicant’s arguments improperly limits the claimed draw sensor to directly sensing movement of the line or rotation of the spool, neither of which is required by claim 2.
Applicant’s arguments in regards to claims 4 and 15 have been fully considered but are not persuasive. Applicant’s arguments address the teachings of Zha and Kullberg individually and do not consider the reference as combined in the rejection. Kullberg discloses a guard at least partially enclosing the trimmer head, while Zha teaches using a Hall sensor in association with the trimmer head to detect operation of the line release mechanism. The rejection relies upon the combined teaching of Kullberg and Zha rather than Zha alone, for the claimed arrangement. Accordingly, Applicant’s arguments do not identify error in the combination.
Conclusion
THIS ACTION IS MADE FINAL. 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 LAURA M LEE whose telephone number is (571)272-8339. The examiner can normally be reached M-F 8a.m.- 5p.m..
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/LAURA M LEE/Primary Examiner, Art Unit 3724
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