Browse Prior Art Database

LOAD BEARING ASSEMBLY TECHNIQUE FOR A POINTER ASSEMBLY

IP.com Disclosure Number: IPCOM000024592D
Original Publication Date: 1981-Apr-30
Included in the Prior Art Database: 2004-Apr-02
Document File: 2 page(s) / 101K

Publishing Venue

Xerox Disclosure Journal

Abstract

A pointer assembly refers to a cursor positioning device used in conjunction with a CRT display terminal. Displacement, speed and direction of the cursor are provided by the pointer. The pointer is a handheld device operated by rolling it over a flat surface. The movements are converted first to the rotation of a trackball and then to the rotation of two encoders (at right angles to each other), which digitize its movement. In order for the trackball to transfer motion to the commutator shaft by means of friction, there must be a normal force imposed between the trackball and the commutator shaft at all times.

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A pointer assembly refers to a cursor positioning device used in conjunction with a CRT display terminal. Displacement, speed and direction of the cursor are provided by the pointer. The pointer is a handheld device operated by rolling it over a flat surface. The movements are converted first to the rotation of a trackball and then to the rotation of two encoders (at right angles to each other), which digitize its movement. In order for the trackball to transfer motion to the commutator shaft by means of friction, there must be a normal force imposed between the trackball and the commutator shaft at all times.

Volume 6 Number 2 March/April 1981 57

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LOAD BEARING ASSEMBLY TECHNIQUE FOR A POINTER ASSEMBLY (Cont'd)

With reference to Figure 1, after trackball 12 has been inserted in housing 18, a load bearing 10 is pressed against the trackball 12 by means of a spring plate 14 to produce the required normal force. During the assembly sequence, the load bearing 10 is centered on shaft 16 and attached thereto with suitable adhesive. The load bearing 10 and shaft 16 are inserted into housing 18 from outside in the direction as indicated by arrow 20. Shaft 16 fits into nest 22 (see Figure 2) with load bearing 10 positioned in aperture 24 in housing 18. Spring plate 24 must be bowed sufficiently to clear load bearing 10 as spring plate 24 is placed into retaining groove 26. This assembly was time consuming and resulted in a high incidence of spring plate damage because the amount of bow that was required to be placed in the spring...