TOPICS

“Electric Impact Tightening Tool”

Overview:

This case involves the overturning of a decision to dismiss a request for a trial for patent invalidation on the grounds that the Corrected Invention 1 of this case could have been easily made by a person skilled in the art based on the Inventions of Plaintiff’s Exhibits 1 and 2 and well-known art.

► Link to a summary and full text of the trial decision (Japanese)

Main Issue:

The appropriateness of identifying the differences between the Corrected Invention 1 of this case and the Invention of Plaintiff’s Exhibit 2 by dividing them into two points, and the errors in the determination of the ease of conception (obviousness) of those differences.

Conclusion:

(2) Comparison between the Corrected Invention 1 of this case and the Invention of Plaintiff’s Exhibit 2

b. …it is recognized that the Corrected Invention 1 of this case and the Invention of Plaintiff’s Exhibit 2 are different in the following points.

Difference I

The Corrected Invention 1 of this case is an “out-rotor” electric motor, whereas the Invention of Plaintiff’s Exhibit 2 is an “inner-rotor” electric motor.

Difference II

Regarding the manner in which magnets are held, the Corrected Invention 1 of this case recites that the magnets “are attached with a gap provided on an outer circumferential side of the stators,” whereas the Invention of Plaintiff’s Exhibit 2 does not clearly indicate the manner in which the magnets are held.

c. …the defendant [the patentee] argues that in identifying the differences, it is appropriate to recognize coherent structures as units from the perspective of solving the technical problem of the invention, but since the configurations of B1 to B4 in claim 1…are matters identifying the invention indicating a coherent technical idea related to the electric motor B, it is inappropriate to extract only the configuration of B2 as an independent Difference II.

However, the issue of how the magnets used in an electric motor are held can be considered independently, regardless of the type of the electric motor…. Consequently,…it should be said that it is possible to distinguish and identify Difference 1 based on the type determined by the positional relationship between the stators and the rotor holding the magnets (inner-motor type and outer-rotor type), and Difference 2 related to the specific manner of holding the magnets, which is a matter unrelated to the type of electric motor. The defendant also argues that dividing the differences is equivalent to requiring multiple steps for ease of conception (obviousness), and cannot be recognized as ease of ease (obviousness based on multiple secondary references applied to a primary reference, i.e., two-step obviousness), but…since Differences I and II of this case are understood to be distinguishable as independent matters, the defendant’s argument is based on a different premise and can cannot be accepted.

(3) Obviousness of Difference I

c. …considering Difference I, the Invention of Plaintiff’s Exhibit 2 relates to an “electric impact tightening tool” (a type of power hand tool), while the Invention of Plaintiff’s Exhibit 1 relates to an “electric motor” applied to a “power hand tool.” Thus, the technical fields of the two are related. Additionally, at the time of the priority date…of this case, in the technical field of “electric impact tightening tools” to which the Invention of Plaintiff’s Exhibit 2 belongs, torque was an important factor in their performance, and increasing torque was a well-known and obvious problem…. Furthermore, at the time of the priority date of this case, it was well-known that it was easier to increase the torque of an outer-rotor motor, such as the one in the Invention of Plaintiff’s Exhibit 1, compared to an inner-rotor motor…. Consequently, …since there is motivation to apply the Invention of Plaintiff’s Exhibit 2 to the Invention of Plaintiff’s Exhibit 1 to solve the well-known problem of increasing torque, a person skilled in the art would have easily conceived of applying the outer-rotor electric motor of the Invention of Plaintiff’s Exhibit 1 to the Invention of Plaintiff’s Exhibit 2 to achieve the configuration of Difference I….

(4) Obviousness of Difference II

b. …considering Difference II, it is…well-known art to dispose, in an outer rotor electric motor, a plurality of magnets along the outer circumferential side of the stators (inner circumferential side of the rotor) and “attach” them by an adhesive bonding method, or the like, to hold the magnets.

Consequently, a person skilled in the art would have easily conceived of applying the well-known art to achieve the configuration of Difference II.

Comments:

The court identified the well-known art in outer rotor electric motors and determined that a person skilled in the art would have easily conceived of applying this well-known art to achieve the configuration of Difference II. However, the electric motor of the Invention of Plaintiff’s Exhibit 2 is an inner rotor type, not an outer rotor type (Difference I). It seems inappropriate to determine that the well-known art in outer rotor electric motors can be applied to the Invention of Plaintiff’s Exhibit 2, which employs an inner rotor electric motor.

If Difference I and Difference II are distinguishable as independent matters as the court points out, the ease of conception (obviousness) of Difference II should be determined regardless of the ease of conception of Difference I. However, it appears that the court first resolved Difference I, and then determined that Difference II could be easily conceived of for the Invention of Plaintiff’s Exhibit 2 in which Difference I has been resolved (which is different from the Invention of Plaintiff’s Exhibit 2).

Norifumi KOBAYASHI