Direct drive rotational sensor adapted to withstand off-axis loading

• US 6,404,417 B1
• Filed: 03/22/1999
• Issued: 06/11/2002
• Est. Priority Date: 03/22/1999
• Status: Expired due to Term

• Current Assignee: Logitech Europe S A (Logitech International SA)
• Original Assignee: Logitech Europe S A (Logitech International SA)
• Inventors: McVicar, David
• Primary Examiner(s): Shalwala, Bipin
• Assistant Examiner(s): Frenel, Vanel
• Application Number:
  US09/273,894
• Time in Patent Office: 1,177 Days
• Field of Search: 345/161, 345/156, 463/36, 463/37, 463/38, 463/46
• US Class Current: 345/161
• CPC Class Codes: G05G 2009/04748 Position sensor for rotary movement, e.g. potentiometer
• CPC Class Codes: G05G 9/047 the controlling member being movable by hand about orthogonal axes, e.g. joysticks for switches H01H25/04
• CPC Class Codes: G06F 3/0334 Foot operated pointing devices
• CPC Class Codes: G06F 3/0362 with detection of 1D translations or rotations of an operating part of the device, e.g. scroll wheels, sliders, knobs, rollers or belts

Abstract

Devices and methods are provided to withstand various off-axis displacements and radial forces which degrade the accuracy of conventional rotational position sensors after repeated use. Specifically, a device is provided having a mounting assembly which reduces the internal bending forces which cause early failure in rotational sensors. In one embodiment, a computer peripheral device includes an input shaft attached to a rotational sensor. The mounting assembly coupled to the rotational sensor prevents motion of the sensor body in only one degree of freedom. Preferably, the mounting assembly allows the sensor body to move with the input shaft in five degrees of freedom, thus minimizing bending forces caused when the sensor body is rigidly secured in one position. The ability to move the sensor body in many degrees of freedom allows forces to be transferred through the device, instead of being absorbed by the sensor mechanisms. Optimally, the rotational sensor will only resist those forces required to rotate the shaft.

Claims

1. A computer peripheral device comprising:

a housing;

an input shaft;

a rotational sensor having a sensor body and a sensor shaft, the sensor shaft being attached to the input shaft, the rotational sensor comprising a protrusion connected to the sensor body; and

a mounting assembly on said housing coupled to said protrusion of said rotational sensor, said mounting assembly having a plurality of surfaces positioned to contact said protrusion with an interference fit to prevent motion of the sensor body in only one degree of freedom such that the sensor body is movable with said input shaft except in said one degree of freedom, said protrusion being slidable relative to said mounting assembly.

2. A device as in claim 1 wherein said mounting assembly prevents rotation of the sensor body about a longitudinal axis of the sensor shaft.

3. A device as in claim 1 wherein said sensor shaft of said rotational sensor forms a rigid connection with said input shaft, said sensor shaft moving with said input shaft.

4. A device as in claim 1 wherein said input shaft has a lumen and said rotational sensor shaft is mounted within said lumen with a direct-drive, interference fit connection.

5. A device as in claim 1 wherein said sensor body of said rotational sensor moves with the input shaft in only five degrees of freedom.

6. A device as in claim 1 wherein said input shaft forms a connection with a foot pedal to receive user input.

7. A device as in claim 1 wherein said input shaft forms a connection with a joystick to receive user input.

8. A device as in claim 1 wherein said protrusion comprises a rectangular tab having a first contact surface and a second contact surfaces.

9. A device as in claim 1 wherein said distal end of the protusion has a bias member allowing for compression of the distal end.

12. A device as in claim 1 wherein said protusion is integrally formed with the sensor body.

13. A device as in claim 1 wherein said mounting assembly comprises a bracket having two opposing surfaces defining a channel for slidably receiving a protrusion on said rotational sensor.

14. A device as in claim 13 wherein said mounting assembly contacts locations on said protrusion that prevent rotation of the sensor body about a longitudinal axis of the input shaft;

said protrusion unconstrained by the mounting assembly to move in the channel between the two opposing surfaces.

15. A device as in claim 13 wherein said opposing surfaces are in contact with said first surface and second surface of the protrusion and prevent the rotation of the rotational sensor body about a longitudinal axis of the input shaft.

16. A device as in claim 13 wherein said mounting assembly comprises a U-shaped bracket.

17. A device as in claim 13 wherein the mounting assembly is integrated onto said housing, said mounting assembly comprising an upper rib on the housing defining a first contact point with said protrusion and a lower rib on the housing defining a second contact point,

wherein said contact points prevent body portion rotation about a longitudinal axis of the shaft and allow relative motion of the rotational sensor body portion in at least three of the remaining degrees of freedom.

10. A device as in clam 1 wherein said protrusion comprises an elongate member having a spherical distal end contacting said surfaces of the mounting assembly.

11. A device as in claim 10 wherein said spherical distal end has a slot therethrough.

18. A computer peripheral device comprising:

a housing;

an input shaft;

a rotational sensor having a sensor body and a sensor shaft, the sensor being attached to the input shaft, the rotational sensor comprising a protusion connected to the sensor body; and

sensor mounting means on said housing contacting said protrusion with an interference fit for substantially constraining said sensor body from rotating about a longitudinal axis of the input shaft while allowing relative motion of the sensor body with respect to said housing in at least three other degrees of freedom including sliding therebetween.

19. A device as in claim 18 wherein said sensor mounting means comprises two opposing surfaces defining a channel that slidably receives a protrusion on said sensor body of said rotational sensor.

20. A device as in claim 18 wherein said sensor mounting means prevents rotational motion of the sensor body about a longitudinal axis of the input shaft.

21. A device as in claim 18 wherein said sensor body comprises a protrusion coupled to said mounting means, said protrusion having a distal portion with a shape selected from the group consisting of a sphere, a cylinder, a disc, and a prism.

22. A device as in claim 18 wherein said sensor mounting means defines a slot having a slot width not more than 0.05 mm greater on each side than a width of a protrusion coupled to the sensor body.

23. A device as in claim 18 wherein said sensor body has a protrusion coupled to said sensor mounting means, has an elongate portion with a length sufficient to maintain angular rotation of the sensor body less than about 1°

of total rotation about said longitudinal axis of the input shaft.

24. A sensor mountable on a mounting assembly for measuring a rotational output of a user input, said sensor comprising:

a sensor body connected to a protrusion and a sensor shaft wherein said sensor body is adapted to define an interface with said mounting assembly forming an interference fit between said protrusion and said mounting assembly to prevent rotational movement of the sensor body in only one axis of rotation of said sensor shaft while allowing relative motion of the sensor body with respect to said mounting assembly in at least three other degrees of freedom including sliding therebetween.

25. A device as in claim 24 wherein said sensor body comprises a protrusion for defining said interface with the mounting assembly.

26. A device as in claim 24 wherein said protrusion has a sphere-shaped distal end.

27. A method for manufacturing a computer peripheral device, the method comprising:

coupling a rotational sensor mounting assembly to a housing;

providing a rotational sensor having a sensor body and a sensor shaft, the rotational sensor comprising a protrusion connected to the sensor body; and

securing the sensor shaft of the rotational sensor to an input shaft and mounting the sensor body with the mounting assembly, wherein said mounting assembly has a plurality of surfaces positioned to contact said protusion with an interference fit to substantially prevent motion of the sensor body in only one degree of freedom relative to the housing such that the sensor body is movable with the input shaft except in said one degree of freedom.