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June 5 2004(Saturday) Yomiuri News Paper, Evening Edition

V character → U character Innovation

Failed of elongate the slot, “Good defeat” realized the traditional

■"+" screw

The revolution has occurred on the back sides, such as familiar home electronics. Appearance is the small ordinal "+ (cross slotted)" screw but the screw is an important backroom person indispensable to the assembly of machines.
For example, about 80 screws are used for one digital camera. The Plus Screw is "the completed product" with which the standard was decided by JIS (Japanese Industrial Standards) .
Even if the driver might come float, and it might break off or the slot of the head of a screw might collapse, everyone given up as the natural fault itself.

One day, for research purpose, the president of the HIOS Inc., (Head Office : Matsudo city Chiba Pref.) which makes an Industrial Electric Driver, and Katsuyuki Totsu (age 63) disassembled rival goods, and have broken the slot of the head of a screw. Totsu , holder of 200 or more patents,. “habit of improvement” naturally woke up.

He thought, “ if the contact surface between screw and driver would increase, the fastening power will become weak per square mm and the fear of the slot-collapse will gone. Because, “ it is more easy for us to push the door with three fingers than two fingers “.
So, he made a screw with elongated-slot, but the driver soon come off with little slant angle from the cross slot and had a “good defeat” and realized the power of the present (traditional cross slotted head screw).

The voice of distress from the work place about the screw is still been heard.
When fastening the screw, we push the driver to prevent from the floating power, and it generates the strain anyway. And this problem of the screw is more serious when the machine is accurate. And the improvement of the driver side was also at the limit.
The same thing are said about the archery, “ bad arrow can not fly straight even if the bow would improved. “ And the challenge mind begun again. Instead of elongate the slot, this time he dug the slot more deep. Breakthrough was a simple idea change. At the traditional screw, the cross section of the slot was V shape.

　About 70 years ago, when the conventional cross slotted head screw was invented,
the driver was designed to pop out from the screw slot so as to prevent the cut off of the head when the extra power was added (when screw was fastened). The “Wisdom” of the weak screw-material era was over looked. Mr. Totsu, after the trial and errors, dug the cross section of the screw as a U shape. And the driver’s tip was no more float. The contact surface between driver and the slot became double and the result was proved to show the complete fastening without heart the slot. He made the special flat driver tool’s tip. Of course, we can use the traditional cross screw tool’s tip also.

　Patents were applied to the 15 nations and already registered in US and China. Now, the screw was first adopted by the Electric Tool maker in 1998 and now widely used at the Liquid Crystal TV, Digital Camera, Copy Machine maker. The screw fastening trouble was decreased to 1/10, and makers themselves welcome the screw as “even the new comer can fasten the screw completely in the short time”.
Mr. Ichiro Inazaki, professor of Keio University (mechanics base engineering), estimated as the “good example of the workplace and show the high potential power of “Monozukuri” in Japan (making things in Japan) .
“After knowing the principle, it is a trivial idea. There are treasure-mountains where no one stopped to and see. We want to spread the new screw to the world”. Dreams of Mr. Totsu are expanded.

（Edited by Mr. Jun Sugimori）

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