FORM 2
FIELD OF THE INVENTION
The present invention relates to determining parameters of wheel, steering and suspension of a vehicle. The present invention more particularly relates to an apparatus and method for measuring distance of the centre of pressure of an automobile wheel.
BACKGROUND OF THE INVENTION
In automotive vehicles, a suspension parameter measuring machine (SPMM) is utilized for measuring Kinematics and Compliance related parameters of the suspension of the vehicles, in particular car. The vehicle is mounted onto the SPMM machine and clamped such that the chassis of the vehicle is stationery with respect to the ground. Then, inputs like force and displacements can be applied to the vehicle through the steering wheel and the road wheels whereas outputs are measured in terms of wheel displacements and changes in steering geometries or parameters such as caster, camber, toe, steering axis angle, caster trail, etc.
All of these parameters can be determined by attaching wheel sensors to the outer portion of the wheel. The wheel sensors are installed on four separate posts for detecting wheel orientations from the position of wheel of the vehicle in order to analyze and calculate the required parameters of the vehicle. These sensors consist of sets of potentiometers and fit onto the wheels through magnets and record respective wheel displacements of the vehicle to be measured or analyzed.
Moreover, it is essential to input the distance of the centre of the mounting head of these potentiometers from the centre of pressure of the respective wheel, while analyzing the suspension parameters of the vehicle. The distance of the wheel
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sensors from the centre of pressure of the wheel varies from vehicle to vehicle, where it is termed as 'Yo'. This'distance needs to be measured for all four wheels and fed into the SPMM machine for accurate calculation of the suspension parameters of the vehicle. Such 'Yo' parameter is extremely necessary when setting up or analyzing a vehicle's suspension layout design and determining suspension linkage ratios.
With reference to the conventional methods and apparatus, none of the prior arts can effectively determine the 'Yo' parameter of a vehicle's suspension such as distance to the centre of pressure of the wheel. However, the conventional measurement of the distance to the centre of pressure of the wheel requires more manpower. Also, it is a time consuming process and an inaccurate method of measurement. In order to address the above specified disadvantages, it is necessary to provide an apparatus and method for measuring distance of the centre of pressure of the wheel in an accurate manner. Such method should also ensure less manpower requirement and time consumption for the measurement.
OBJECT OF THE INVENTION
An object of the present invention is to provide an apparatus for measuring distance of the centre of pressure of an automobile wheel, which minimizes manpower and cost consumption for the measurement.
Another object of the present invention is to provide an apparatus for measuring distance of the centre of pressure of an automobile wheel, which is simple in construction, convenient in measurement and also provides more accurate measurement.
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Yet another object of the present invention is to provide a method for measuring distance of the centre of pressure of an automobile wheel, which requires less time for the measurement.
SUMMARY OF THE INVENTION
According to one aspect, the present invention, which achieves the objectives, relates to an apparatus for measuring distance (Yo) of the centre of pressure of an automobile wheel comprising a metal plate member provided with dowel pins for locating the plate member in dowel holes provided on a wheel pad. A scale is attached to a slider means, and a plum bob is configured with a sleeve to project a position of a pin-hole at the centre of a swivel head, which carries potentiometers. The slider means slides on the metal plate to align the scale with the location of the pin-hole while the plum bob is projected down onto the scale. This point of projection of the plum bob on the scale provides a direct reading of the distance of the centre of pressure of the wheel, which enables accurate measurement and also minimizes manpower, time and cost consumption for the measurement.
According to another aspect, the present invention, which achieves the objectives, relates to a method for measuring distance (Yo) of the centre of pressure of an automobile wheel involving: attaching the plate member onto the wheel pad with the dowel pins located in the dowel holes after aligning the central axis of the wheel pad with the centre of pressure of the wheel. The scale is placed on the slider means sliding on the plate member. Then, the thread of the plum bob is passed through the pin-hole on the swivel head with a set of potentiometers until the plum bob touches the scale. The scale is moved by using the slider means until the markings on the scale are positioned below the plum bob. The reading on the
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scale is recorded as the distance of the centre of pressure of the wheel after the plum bob stops swinging.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention will be discussed in greater detail with reference to the accompanying Figures.
FIG. 1 shows a schematic view of an apparatus for measuring distance (Yo) of the centre of pressure of an automobile wheel, in accordance with an exemplary embodiment of the present invention.
DETAILED DESCRIPTION OF THE INVENTION
Referring to FIG. 1, a schematic view of an apparatus for measuring distance (Yo) of the centre of pressure of an automobile wheel (3) is illustrated, in accordance with an exemplary embodiment of the present invention. The apparatus comprises a rectangular metal plate member (5) that are machined and grounded. The plate member (5) is provided with two dowel pins (10) at its ends. The dowel pins (10) are configured to locate the metal plate (5) in dowel holes (10) provided on the wheel pad (4) on which the wheel (3) is placed and whose centre of pressure is measured.
Furthermore, a metal scale (8) is attached to a machined and ground slider means (6) that slides on the metal plate (5). A plum bob (2) is provided with a sleeve in order to project the position of a pin-hole (9) at the centre of a swivel head (1) on which a set of potentiometers (7) is carried. The slider means (6) is configured to slide on the metal plate (5) for aligning the metal scale (8) with the location of the
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pin-hole (9) while the plum bob (2) is projected down onto the scale (8). The point of projection of the plum bob (2) on the scale (8) provides a direct reading of the distance (Yo) of the centre of pressure of the wheel (3), which enables accurate measurement and also minimizes manpower, time and cost consumption for the measurement.
Moreover, the central axis of the wheel pad (4) is aligned with the centre of pressure of the wheel (3) on the suspension parameter measuring machine (SPMM), which is called as centralization operation. The scale (8) is cut and fixed on the slider means (6) in such a manner that the scale (8) compensates for the distance from the centerline of centre of pressure of the wheel (3) to the dowel holes (10). Hence, the reading of the scale (8), in particular the point at which the plum bob (8) touches the scale (8), is the reading of the distance (Yo) of the centre of pressure of the wheel (3) of an automobile. Such a measuring apparatus is simple in construction and also convenient in measurement.
While measuring the distance of centre of pressure of the wheel (3) of an automobile, the vehicle is clamped onto the SPMM. The centre of pressure of the wheel (3) is measured and the central axis of the wheel pad (4) is aligned with centre of pressure of the wheel (3). The wheel station sensors are attached and aligned through the magnet, and the metal plate member (5) is placed onto the wheel pad (4) with dowel pins (10) located in dowel holes. The scale (8) is attached on the slider means (6) that slides on the plate member (5).
Thereafter, the thread of the plum bob (2) is passed through the pin hole (9) on the swiveling head (1) with potentiometers (7) and released in a lengthwise manner until the plum bob (2) touches the scale (8). Then, the scale (8) is smoothly moved by the slider means (6) such that the markings on the scale (8) are positioned
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below the plum bob (2). Finally, the reading on the scale (8), i.e. where the plum bob (2) touches the scale (8), is recorded as the distance (Yo) of the centre of pressure of the wheel (3) after the plum bob (2) stops swinging.
The foregoing description is a specific embodiment of the present invention. It should be appreciated that this embodiment is described for purpose of illustration only, and that numerous alterations and modifications may be practiced by those skilled in the art without departing from the spirit and scope of the invention. It is intended that all such modifications and alterations be included in, so far as they come within the scope of the invention as claimed or the equivalents thereof.
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WE CLAIM
1. An apparatus for measuring distance of the centre of pressure of an
automobile wheel and wheel sensors, comprising:
a plate member provided with at least two dowel pins for locating said plate member in dowel holes provided on a wheel pad;
a scale attached to a slider means; and
a plum bob configured with a sleeve to project a position of a pin-hole at the centre of a swivel head carrying a plurality of potentiometers, wherein said slider means slides on said plate member to align said scale with the location of said pin-hole while said plum bob is projected down onto said scale, thereby facilitating measurement of the distance of the centre of pressure of the wheel and wheel sensors.
2. The apparatus as claimed in claim 1, wherein the central axis of said wheel pad is aligned with the centre of pressure of the wheel when the wheel is placed on said wheel pad.
3. The apparatus as claimed in claim 1, wherein said scale is cut and fixed such that said scale compensates for the distance from a centerline of the centre of
pressure to said plate member.
4. The apparatus as claimed in claim 1, wherein said dowel pins are arranged at both ends of said plate member.
5. A method for measuring distance of the centre of pressure of an automobile wheel and wheel sensors, comprising:
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attaching a plate member onto a wheel pad with at least two dowel pins located in dowel hc>les after aligning a central axis of said wheel pad with the centre of pressure of the wheel;
placing a scale attached on a slider means sliding on said plate member;
passing thread of a plum boh through a pin hole on a swivel head with a plurality of potentiometers until said plum bob touches said scale;
sliding said scale by using said slider means until the markings on said scale are positioned below said plum bob; and
recording the reading on said scale as the distance of the centre of pressure of the wheel and wheel sensors after said plum bob stops swinging.
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6. The method as claimed in claim 5, wherein the centre of pressure of the wheel is measured after clamping the vehicle onto a suspension parameter measuring machine.
7. An apparatus for measuring distance of the centre of pressure of an automobile wheel and wheel sensors as hereinabove described with reference to the accompanying drawings.
8. A method for measuring distance of the centre of pressure of an automobile wheel and wheel sensors as hereinabove described with reference to the accompanying drawings.