Wheel balancing apparatus and method

• US 5,365,786 A
• Filed: 06/05/1992
• Issued: 11/22/1994
• Est. Priority Date: 06/05/1992
• Status: Expired due to Fees

• Current Assignee: Therasense Incorporated (Abbott Laboratories)
• Original Assignee: Hunter Engineering Company
• Inventors: Douglas, Michael W.
• Primary Examiner(s): NOT, DEFINED
• Assistant Examiner(s): Kwok, Helen C.
• Application Number:
  US07/893,768
• Time in Patent Office: 900 Days
• Field of Search: 73/462, 73/468, 73/470, 301/5.21, 301/5.22, 364/463, 364/506, 364/507, 364/508
• US Class Current: 73/462
• CPC Class Codes: G01M 1/225 for vehicle wheels in situ G01M1/28
• CPC Class Codes: G01M 1/32 by adding material to the body to be tested, e.g. by correcting-weights

Abstract

Balancing a wheel and tire assembly includes sensing imbalance of a wheel and tire assembly and determining therefrom the magnitude and placement of at least one correction weight to correct the imbalance. The magnitude of the correction weight is compensated to correct for curvature of actual correction weights. The compensated magnitude is displayed to the user. If the weight amount or placement spot is inconvenient for the user, the user can initiate a split weight procedure which determines a pair of weight magnitudes and weight placements which are vectorially equivalent to the corresponding single correction weight in terms of correcting imbalance. The pair of weight magnitudes are reverse compensated for curvature to calculate the effective weights thereof and the weight placements are calculated based upon the effective weights.

Claims

1. Apparatus for balancing a wheel and tire assembly comprising:

means for sensing imbalance of a wheel and tire assembly;

means responsive to said sensing means for determining the magnitude and placement of at least one correction weight to correct the imbalance, said determining means further including means for compensating the determined magnitude of the correction weight to correct for curvature of said correction weight;

means for displaying to a user the compensated magnitude of the correction weight;

manually operable means for entering the diameter of the wheel being balanced, said determining means having stored therein different compensation factors for different wheel diameters;

said determining means being responsive to the entered wheel diameter and to the correction weight to compensate for curvature, for an entered wheel diameter, only said at least one correction weight heavier than a predetermined minimum correction weight limit, each of a plurality of wheel diameters having associated therewith its own said predetermined minimum correction weight limit above which compensation occurs.

2. The wheel and tire assembly balancing apparatus as set forth in claim 1 wherein said predetermined minimum correction weight limit above which compensation occurs for a wheel having a first diameter smaller than said predetermined minimum correction weight limit for wheels having diameters larger than said first diameter.

3. Apparatus for balancing a wheel and tire assembly comprising:

means for sensing imbalance of a wheel and tire assembly;

means responsive to said sensing means for determining the magnitude and placement of at least one correction weight to correct the imbalance, said determining means further including means for compensating the determined magnitude of the correction weight to correct for curvature of said correction weight;

means for displaying to a user the compensated magnitude of the correction weight;

manually operable means for entering the diameter of the wheel being balanced, said determining means having stored therein different compensation factors for different wheel diameters;

said different compensation factors for wheel diameters corresponding to different wheel diameters separated by one inch increments.

4. Apparatus for balancing a wheel and tire assembly comprising:

means for sensing imbalance of a wheel and tire assembly;

means responsive to said sensing means for determining the magnitude and placement of at least one correction weight to correct the imbalance, said determining means further including means for linearly compensating the magnitude of the correction weight to correct for curvature of correction weights; and

means for displaying to a user the compensated magnitude of the correction weight;

said means for compensating takes the form of C.W.=(I.W.-P.W.) * C.F.+P.W., where C.W. is the compensated weight, I.W. is the calculated balancing weight without compensation for curvature, P.W. is a predetermined weight below which no compensation takes place, and C.F. is a compensation factor.

5. The wheel and tire assembly balancing apparatus as set forth in claim 4 wherein C.F. varies with different wheel diameters and weight types.

6. The wheel and tire assembly balancing apparatus as set forth in claim 4 wherein C.F. varies for adhesive weights and hammer-on weights for the same wheel diameter.

7. The wheel and tire assembly balancing apparatus as set forth in claim 4 wherein P.W. varies for adhesive weights and hammer-on weights for the same wheel diameter.

8. The wheel and tire assembly balancing apparatus as set forth in claim 4 further including manually operable means for selecting the type of correction weight being used, said compensating means being responsive to the selection of a particular type of correction weight to use the P.W. and C.F. for that particular type of correction weight in compensating for curvature of said weight.

9. Apparatus for balancing a wheel and tire assembly comprising:

means for sensing imbalance of a wheel and tire assembly;

means for determining the magnitude and placement of at least a single correction weight to substantially correct the imbalance;

means for providing a split weight signal to said determining means, said determining means being responsive to the split weight signal to determine for said single correction weight a pair of correction weights having weight magnitudes and weight placements which are vectorially equivalent to the corresponding single correction weight in terms of correcting imbalance, said determining means including means for compensating said weight magnitudes and weight placements to correct for curvature of the pair of correction weights;

said determining means compensating by calculating the effective weights of the pair of correction weights and determining the placements of said pair of correction weights corresponding to the calculated effective weights;

said effective weights being determined by the determining means as a linear function of the pair of correction weights.

10. Apparatus for balancing a wheel and tire assembly comprising:

means for sensing imbalance of a wheel and tire assembly;

means for determining the magnitude and placement of at least a single correction weight to substantially correct the imbalance;

means for providing a split weight signal to said determining means, said determining means being responsive to the split weight signal to determine for said single correction weight a pair of correction weights having weight magnitudes and weight placement which are vectorially equivalent to the corresponding single correction weight in terms of correcting imbalance, said determining means including means for compensating said weight magnitudes and weight placements to correct for curvature of the pair of correction weights;

said determining means compensating by calculating the effective weights of the pair of correction weights and determining the placements of said pair of correction weights corresponding to the calculated effective weights;

said determining means compensating for curvature of the pair of correction weights only when a correction weight exceeds a predetermined weight.

11. The wheel and tire assembly balancing apparatus as set forth in claim 10 wherein the predetermined weight varies with wheel diameter and weight type.

12. A method of balancing a wheel and tire assembly comprising:

sensing imbalance of a wheel and tire assembly;

determining from the sensed imbalance the magnitude and placement of at least one correction weight to correct the imbalance;

compensating the determined magnitude of the correction weight to correct for curvature of said correction weight; and

displaying to a user the compensated magnitude of the correction weight to enable the user to place a correction weight of the compensated magnitude on the wheel and tire assembly;

compensating the magnitude of the correction weight for actual weight curvature by different amounts for different wheel diameters only for the correction weight above a predetermined minimum correction weight limit.

13. The method of balancing a wheel and tire assembly as set forth in claim 12 wherein said predetermined minimum correction weight limit at which compensation for weight curvature begins varies with wheel diameter and weight type.

14. The method of balancing a wheel and tire assembly as set forth in claim 13 wherein said predetermined minimum correction weight limit for a wheel having a first diameter is smaller than the predetermined minimum weight limit for wheels having diameters larger than said first diameter.

15. A method of balancing a wheel and tire assembly comprising:

sensing imbalance of a wheel and tire assembly;

determining from the sensed imbalance the magnitude and placement of at least one correction weight to correct the imbalance;

compensating the determined magnitude of the correction weight to correct for curvature of said correction weight; and

displaying to a user the compensated magnitude of the correction weight to enable the user to place a correction weight of the compensated magnitude on the wheel and tire assembly,

compensating the magnitude of the correction weight for actual weight curvature by different amounts for different wheel diameters;

and having a different compensation factors for different wheel diameters corresponding to wheel diameters separated by one inch increments.

16. A method of balancing a wheel and tire assembly comprising:

sensing imbalance of a wheel and tire assembly;

determining from the sensed imbalance the magnitude and placement of at least one correction weight to correct the imbalance;

linearly compensating the magnitude of the correction weight to correct for curvature of said correction weight; and

displaying to a user the compensated magnitude of the correction weight to enable the user to place a correction weight of the compensated magnitude on the wheel and tire assembly;

said compensating takes the form of C.W.=(I.W.-P.W.) * C.F.+P.W., where C.W. is the compensated weight, I.W. is the calculated balancing weight without compensation for curvature, P.W. is a predetermined weight below which no compensation takes place, and C.F. is a compensation factor.

17. The method of balancing a wheel and tire assembly as set forth in claim 16 wherein C.F. varies with different wheel diameters and weight type.

18. The method of balancing a wheel and tire assembly as set forth in claim 16 wherein C.F. varies for adhesive weights and hammer-on weights for the same wheel diameter.

19. The method of balancing a wheel and tire assembly as set forth in claim 16 wherein P.W. varies for adhesive weights and hammer-on weights for the same wheel diameter.

20. The method of balancing a wheel and tire assembly as set forth in claim 16 further including manually selecting the type of correction weight being used, and using the P.W. and C.F. for that particular type of correction weight in compensating for curvature of said weight.

21. A method of balancing a wheel and tire assembly comprising:

sensing imbalance of a wheel and tire assembly;

determining the magnitude and placement of at least a single correction weight to substantially correct the imbalance;

determining for said single correction weight a pair of correction weights having weight magnitudes and weight placements which are vectorially equivalent to the corresponding single correction weight in terms of correcting imbalance, said weight magnitudes and weight placements being corrected for curvature of the pair of correction weights; and

calculating the effective weight of said pair of correction weights and determining the placement of said pair of correction weights corresponding to the calculated effective weights.

22. The method of balancing a wheel and tire assembly as set forth in claim 21 wherein the effective weights are linear functions of the actual weights.

23. The method of balancing a wheel and tire assembly as set forth in claim 21 including compensating for curvature of the correction weights only when a correction weight exceeds a predetermined weight.

24. The method of balancing a wheel and tire assembly as set forth in claim 23 wherein the predetermined weight varies with wheel diameter and weight type.