Abstract: A sliding mechanism comprises a sleeve member, two balls in the sleeve member, and an elastic member biased between the balls for urging each ball to project above either opening of the sleeve member. When the sliding mechanism is mounted on a second member, a reduction of friction and a permanent contact between the first and second members are effected because the second member is slidable with respect to a first member with balls being in elastic contact with the first member. This may reduce friction and maintain a permanent contact when first and second members are relatively moving.

Abstract: The present invention relates to a portable data processing device comprising an exchanging mechanism for alternatively concealing the data processing device or the handle thereof. By means of the exchanging mechanism, the data processing device and the handle thereof can be alternatively exposed to the outside during the working status or portable status. In addition to the advantage of easy portability, the design that the data processing device and the handle thereof are accommodated within the same space is also advantageous of reducing the space occupied by the data processing device and protecting the data processing device in the portable status.