Measuring and testing – Rotor unbalance – Dynamic
Reexamination Certificate
1999-05-06
2001-06-12
Chapman, John E. (Department: 2856)
Measuring and testing
Rotor unbalance
Dynamic
C301S005210
Reexamination Certificate
active
06244108
ABSTRACT:
The present invention relates to a wheel balancer, and in particular, though not limited to a wheel balancer for balancing an alloy vehicle wheel, and in which balance weights, are, in general, attached to the inner surface of the portion of the wheel hub which defines the wheel well. In general, such weights are secured to the wheel well by an adhesive, and typically, are located on the inner side of the wheel, in other words, on the inner side relative to the spokes of the wheel, out of sight when the wheel is attached to a vehicle for aesthetic purposes.
Wheel balancers for balancing wheels are well known, and in general, fall into two categories, namely, dynamic and static balancers. Dynamic balancers fall into two sub-categories, namely, slow speed and high speed balancers. In slow speed dynamic balancers, the wheel is mounted on a main shaft of the balancer, and in general, is rotated by hand. In high speed dynamic balancers, the main shaft onto which the wheel is attached, in general, is rotated by a drive motor. The present invention while in general, it relates to a dynamic wheel balancer, also relates to a static wheel balancer, and as a dynamic wheel balancer may be a high speed or a low speed balancer.
In the balancing of alloy wheels, it is important for aesthetic purposes that the balance weights should be attached to the alloy wheel hub out of sight when the wheel is attached to a vehicle. For this and other reasons, clip-on weights of the type which are typically attached to the inner and outer rims of steel wheel hubs are unsuitable for balancing alloy wheels. Weights which are generally used in balancing alloy wheels are referred to as stick-on weights, and are provided with a self-adhesive coating for bonding the weight to an inner surface of the wheel hub, which defines a wheel well. Typically, the weights are attached to the surface defining the well at locations in two spaced apart balancing planes which are located between the spokes of the wheel hub and the inner rim of the wheel hub, in other words, on the inner side of a plane defined by the spokes of the wheel hub. In this way, when the wheel is attached to the vehicle the weights, in general, are largely out of sight. The balancing planes are axially spaced apart relative to the axis of rotation of the wheel, and preferably, the balancing planes are spaced apart a distance of at least 50 mm. In wide rim wheels the spacing between the balancing planes, in general, is considerably greater.
Since, in general, there are no markings or identifications which would identify the balancing planes on alloy wheel hubs, great care is required when the balance weights are being attached to the wheel hub. Indeed, even with great care, in general, it is difficult to accurately locate the balance weights, and in particular, it is difficult to accurately locate the balance weights in an axial direction relative to the rotational axis of the alloy wheel. Wheel balancers are known which comprise an arm for applying balance weights in the appropriate positions in the balancing planes in the wheel hub. In such wheel balancers, each balance weight is placed in a clamp at a free end of the arm which is then extended until the balance weight in the clamp co-incides with the balancing plane. Such wheel balancers are relatively complex, expensive and are not always accurate, and in general, require special purpose balance weights.
The present invention is directed towards providing a wheel balancer which overcomes these problems, and to a method for using a wheel balancer for overcoming the problems.
According to the invention there is provided a wheel balancer for measuring imbalance in a vehicle wheel in a balancing plane normal to the axis of rotation of the vehicle wheel, and for indicating the position on the wheel at which a balance weight is to be located for correcting the imbalance, the wheel balancer comprising a support means, a main shaft rotatable about a rotational axis in the support means, a receiving means located on the main shaft for receiving the vehicle wheel with the axis of rotation of the vehicle wheel co-axial with the rotational axis of the main shaft, a sensing means for detecting the balancing plane of the vehicle wheel and a balance weight receiving location adjacent the balancing plane, and for generating signals representative of the position of the balancing plane along the rotational axis relative to a reference plane and the radius of the balance weight receiving location adjacent the balancing plane, a monitoring means for monitoring rotation of the main shaft and for generating signals representative of the magnitude and angular direction of imbalance forces in the main shaft, a computing means for computing the magnitude of a correcting balance weight and the angular position of the balance weight to be located at the balance weight receiving location in the balancing plane for correcting the imbalance in response to signals generated by the sensing means and the monitoring means, and a position indicating means responsive to the computing means for indicating the angular position relative to the wheel axis at which the correcting balance weight is to be located, wherein the position indicating means indicates a balance weight position in the balance weight receiving location adjacent the balancing plane at which the correcting balance weight is to be located, the angular position of the balance weight position and its position relative to the reference plane being indicated by the position indicating means, and the position indicating means indicates the balance weight position by means of a visually perceptible indication on the wheel.
The advantages of the invention are many. One particularly important advantage of the invention is achieved by virtue of the fact that the position indicating means indicates the balance weight position by means of a visually perceptible indication on the wheel. Since the indication is a visually perceptible indication, it can readily easily be identified by an operator, and the balance weight can be accurately located by the operator in the balance weight position.
Preferably, the indicating means is adapted for indicating the balance weight position when the wheel is in a rotational position such that the balance weight position is located in a position which is accessible to the operator. The advantage of this feature of the invention is that it allows ready access to the operator to the balance weight position.
Advantageously, the indicating means is adapted for indicating the balance weight position when the rotational position of the wheel is such that the balance weight position is located in a position which is visually accessible to the operator. The advantage of this feature of the invention is that it significantly increases the accuracy with which the balance weight position can be identified by the operator, and also the accuracy with which the correcting balance weight can be attached to the wheel.
Ideally, the rotational axis defined by the main shaft extends horizontally, and the position indicating means is adapted for indicating the balance weight position when the balance weight position is located in a lower half of the wheel relative to the main shaft. The advantage of this feature of the invention is that it further enhances access by the operator to the balance weight position, thus further enhancing the accuracy and ease with which a correcting balance weight can be attached to the wheel at the balance weight position.
In one embodiment of the invention, the position indicating means is adapted for indicating the balance weight position when the balance weight position lies in a position at an angle in the range of ±30° to ±80° from bottom dead centre of the wheel. Preferably, the position indicating means is adapted for indicating the balance weight position when the balance weight position lies in a position at an angle in the range of ±45° to ±75° from bottom dead centre of the wheel. Advantageously,
Cullen Richard J
Fogarty Padraig
McInnes Duncan W
Meaney Paul P
Chapman John E.
Snap-On Equipment Europe Limited
Sughrue Mion Zinn Macpeak & Seas, PLLC
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