Abstract:
A control stick device having a switch disabled stick bias, a screw-adjustable biasing of internal potentiometers, and a one-piece frame for receiving a snap-fit stick element.

Description:
BACKGROUND OF THE INVENTION 
     The subject invention relates to a &#34;joystick&#34; control device, and more particularly to such a control device useful in connection with drawing on computer displays and with electronic game and other toy apparatus. 
     In the prior art, control sticks are known in which a ball-and-socket rotatable stick member is mechanically linked to orthogonal fork members to drive respective X and Y axis potentiometers. With the increasing sophistication of computer graphics apparatus and electronic games, a need has arisen to provide additional control modes and simplified, flexible adjustment of such modes. There is also a continuing need to reduce the cost of the control stick mechanism. 
     SUMMARY OF THE INVENTION 
     It is therefore an object of the invention to provide an improved control stick apparatus. 
     It is another object of the invention to expand the control features available with a control stick device, while providing simple feature selection mechanisms. 
     It is another object of the invention to provide a control stick apparatus with simplified manufacturing and assembly features. 
     These and other objects are achieved by a control stick device employing an adjustment feature which enables biasing of the associated potentiometers through a geared mechanism and one-step disabling of spring-biased return members used to maintain the control stick in a centered position. The preferred embodiment features a single piece frame structure with a snapably-insertable ball and stick member, reducing the multiplicity of parts required by the structure. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The preferred embodiment and best mode of implementing the just-summarized invention will now be described in conjunction with the drawings of which: 
     FIG. 1 is a perspective view of a joystick control according to the preferred embodiment 
     FIG. 2 is a bottom view illustrating the control mechanism of the preferred embodiment; 
     FIG. 3 is a sectional view taken along Section 3--3 of FIG. 2, illustrating biasing apparatus according to the preferred embodiment; 
     FIG. 4 illustrates the potentiometer adjustment mechanism of the preferred embodiment; 
     FIG. 5 is an exploded perspective view of the preferred embodiment; and 
     FIG. 6 is a perspective of the frame member of the preferred embodiment. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     FIG. 1 illustrates a control box 11 having a control stick mechanism 13 including a control stick shaft 16 mounted therein. The box includes rotatable adjustment members 15, 17 and slidable adjustment switches 19, 21. Control buttons 23, 25 are also provided. 
     The bottom view of FIG. 2 illustrates the control stick mechanism 13, which includes a frame 14 mounting various parts of the mechanism 13. These parts include first and second potentimeters 27, 29 having shafts 31, 33. Each potentiometer 27, 29 is attached to a respective plate 35, 37, which is integrally formed with a respective gear 39, 41. The potentiometer shafts 31, 33 rotate within and with respect to the gear plate combinations 35, 39; 37, 41, and are press-fit into respective orthogonal fork members 43, 45. Worm shafts 46, 48 are integrally formed with the adjustment members 15, 17 and mesh with the gears 39, 41. 
     Each fork member 43, 45 is pivotally mounted in a respective side 47, 49 of the frame 14 by means of respective pins 44, 42 formed as an integral part of the fork members 43, 45. The fork members 43, 45 bear respective slots 50, 52. The shaft 16 of the joystick mechanism 13 extends through the slots in each fork member 43, 45, providing an X drive to fork 43 and a Y drive to fork 45. 
     The apparatus further includes first and second return members 51, 53 for returning the control stick to a central position. The first return member 51 is pivotally mounted by a pin 59 at one of its ends 55, and the second return member 53 is pivotally mounted by a pin 61 at one of its ends 57. The opposite ends of each return member 51, 53 are attached via bias springs 63, 65 to the frame 14. 
     One of the return members 51 is shown in more detail in FIG. 3. As shown, the return member 51 is contoured to pivot about the pin 44 of the fork member 53. The return member 51 has a first surface 67 and a second surface 69 stepped-up from the first surface 67. The first and second surfaces 67, 69 normally abut complementary detents 71, 73 formed on the fork 43. The detents 71, 73, surfaces 67, 69 and spring 63 interact such that a departure of the fork 43 from its central position exerts a force against the bias of spring 63. The interaction of the spring 63, return member 51 and detents 71, 73 maintain the fork 43 in the center of its permitted arc of travel. The other return member 53 is preferably a mirror image of member 51 and functions to bias the fork 45 in the center of its permitted arc of travel. 
     As further shown in FIG. 3, a cam 75 is provided on each of the slide switches 19, 21. The cam 75 interacts with a beveled surface 77 on the return member 51. When the switch 21 is moved in the direction of the arrow 79, the cam 75 exerts a force against the spring bias and drives the return member 53 out of engagement with the detents 71, 73, disabling the return mechanism. Sliding the control switch 21 in the opposite direction of the arrow 79 re-enables the return mechanism. Disabling and enabling the return mechanism is accomplished without manipulation of the control stick itself. 
     Turning to FIG. 4, it may be seen that the worm shaft 46 extends into the housing 11, where its threads engage the gear 39 attached to the plate 35. Turning the adjustment member 17 pivots the associated potentiometer 27 with respect to its shaft, providing the capability to adjust or preset the starting position of a display feature in an X-Y grid under control of the preferred embodiment. This feature provides a 60% increase in the maneuverabilty of the starting position. 
     The control stick mounting is improved in the preferred embodiment by the use of a one-piece metal stick 16 and ball 18 in combination with a plastic socket 81 (FIG. 6) in the frame 14. By properly tolerancing molding of the plastic socket 81, the ball 16 may be snapped into the frame 14, avoiding the necessity for a multiplicity of parts and additional assembly steps to retain the ball 16. The frame 14 is advantageously of a one-piece molded plastic construction, further simplifying manufacture and assembly. The molded features include mounting spaces 83, 90 for the potentiometer mechanisms 27, 35, 39 and 29, 37, 41. Slots 89, 91 provide bearing surfaces for the collars 93, 95 of the gears 39, 41, leaving the potentiometers 27, 29 free to rotate with respect to the enclosing spaces 90, 83 in the frame 14. The frame further includes slots 85, 87 for retaining the fork pins 42, 44, as well as complementary mounting apertures for the mounting pins 59, 61 of the return members 51, 53. 
     As will be apparent, the just-described preferred embodiment is subject to numerous modifications and adaptations without departing from the scope and spirit of the invention. Therefore, it is to be understood that, within the scope of the appended claims, the invention may be practiced other than as specifically described herein.