Electricity: circuit makers and breakers – Multiple circuit control – Pivoted contact
Reexamination Certificate
1998-05-22
2001-03-13
Scott, J. R. (Department: 2832)
Electricity: circuit makers and breakers
Multiple circuit control
Pivoted contact
C345S161000
Reexamination Certificate
active
06201196
ABSTRACT:
FIELD OF THE INVENTION
The present invention generally relates to a joystick assembly.
BACKGROUND OF THE INVENTION
A joystick can be used in a variety of applications. For instance, a joystick may be used as a computer input device or as a mouse replacement; as a control stick for controlling the movements of mobile or stationary equipment, such as self-propelled wheelchairs for the handicapped, excavators and robots; as a slide for mixing board potentiometers; for parameter modification in machine control; and for manual entry of variable scale magnitudes. These known uses for joysticks share the common property that the greater the manually effected deflection, the greater the resulting change in the variables will be; the more rapidly the deflection must be performed, the more rapidly the variable should change. For the handicapped, who must act with the muscles in the remaining stump of an amputated extremity to control a prosthesis or a vehicle, such joysticks are difficult to operate, if at all, because the radius of action within which these persons can still exert a controlled muscle force no longer covers the stroke of such displacement-dependent joysticks. Finally, the large stroke input also requires a large amount of space for the construction and operation of these joysticks. This deficiency exists not only with potentiometer entries, but generally for displacement sensors for the generation of analog control signals, for example, in pivot lever systems for linear displacements with internal kinematic conversion. In addition, lever systems in joysticks often have the disadvantage of nonlinear reactions to the input stroke, which complicates some control tasks. Joysticks with bending elements with wire resistance strain gauges according to GB 2,211,280 A or EP 0,151,479 A or with Hall elements according to WO 93/20535 A as sensors have similar disadvantages. If the manually executed stroke is limited, the resolution, and thus the precision and reproducibility of the setting, is reduced. Moreover, such joysticks which are actuated by displacement inputs present, from a manufacturing standpoint, a solution which is quite expensive and sensitive to mechanical interference, such as, sensitivity to impact or shock. Although the latter drawback does not strictly apply to key pairs, for example, the buttons or remote volume controls of a radio receiver, the precise fine tuning of a nearly achieved specified valve is complicated even for keys reacting at two speeds, and thus is imprecise in practice.
SUMMARY OF INVENTION
The present invention provides a robust single-axis or multi-axis joystick which can be encapsulated to protect against contamination, yet remain easily accessible and resistant to impact. With this joystick, a person can enter values with great accuracy, reproducibility and dynamic response, all without becoming fatigued over a long time. Advantageously, the rest position (e.g., the null position) should be particularly easy to find from any position, and in addition implementation of the joystick should be cost effective, because it is very simple, compact and reliable.
The present invention is primarily a single-axis or multi-axis joystick, which can receive inputs from a user with virtually no displacement of an input handle. As such, the joystick can be used in a fatigue-free manner, with minimal use of force, so that persons with extremely severe motor impairment can use it. The core of this solution is a mechanically stable, simply designed but precise suspension of a one- or two-arm lever, preferably tared to a neutral equilibrium, which rests almost without clearance against sensors which are engageable with virtually no displacement of the lever. The lever includes a handle extending out of a sealed housing. The handle is pivotable about an axis to receive manual inputs transverse to the pivot axis. In contrast to known displacement-dependent joysticks, the joystick of the present invention operates practically without mechanical deflection and without free play. Advantageously, the pressure input direction is not unintentionally lost, as in the case of movement along a freely specifiable path in a two-axis system. This has a particularly positive effect on the control of cursor movement, for example, during CAD entry. Displacement-free joysticks can also be cascaded for very precise two-axis entry because their handles can be arranged one inside the other with low radial clearance.
The pressure exerted on the sensor can also be integrated by signal-processing technology as long as the pressure remains present, and for the case of a known pressure dependence of the physical sensor behavior, thus permits the implementation of pressure measurement tasks and also force measurement tasks in the case of pressure application to a constant surface area. Thus, the swing of the output signal, e.g., the path length of a linear cursor movement or the end position of a digital display device, is dependent on the duration of the pressure input, and the dynamic response of the signal, e.g., the speed of the movement of a cursor on the display screen or the rate of change of the digital display device, is dependent on the intensity of the pressure currently being manually applied, with practically no displacement, to the handle.
Therefore, this joystick is particularly well suited for industrial use under rough environmental conditions, for those handicapped who have limited bodily movement, and for surgeons to control motorized aids during surgery.
Although in the context of the present invention, the housing of the joystick is mounted rigidly with the handle projecting therefrom to receive inputs, it is within the purview of this invention that the handle be mounted rigidly and the actuation forces be inputted through a manually accessible housing.
REFERENCES:
patent: 2841659 (1958-07-01), Eitel
patent: 3238316 (1966-03-01), Voss
patent: 3293381 (1966-12-01), Eitel
patent: 3360620 (1967-12-01), Ward
patent: 3835270 (1974-09-01), Dufresne
patent: 4414438 (1983-11-01), Maier et al.
patent: 4470320 (1984-09-01), Kim
patent: 5831596 (1998-11-01), Marshall et al.
patent: 151479 (1985-08-01), None
patent: 0151479A3 (1985-08-01), None
patent: 0616298A1 (1994-09-01), None
patent: 616298 (1994-09-01), None
patent: 2211280 (1989-06-01), None
patent: WO 93-20535 (1993-10-01), None
Scott J. R.
Wood Herron & Evans L.L.P.
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