DESC:FIELD OF THE INVENTION

The present invention relates to automotive vehicle alignment. In particular, the present invention relates to a fixture for setting the axle parallelism on the vehicle chassis. More particularly, the present invention relates to check and confirm on the chassis line, the value of axle parallelism at the time of fitment thereof. The present invention also relates to a method for checking and confirming on the chassis line, the value of axle parallelism on the vehicle chassis at the time of fitment thereof.

BACKGROUND OF THE INVENTION

There are four significant components of vehicle alignment: toe, camber, caster and axle parallelism. Of the four, axle parallelism is the cause of most alignment problems. Automotive axles are determined to be parallel, if the measurement between two or more axles is equal at both ends of the axle. Axle parallelism is clearly related to wheel alignment. Axle parallelism is important for articulated vehicles having a plurality of axles, e.g. trailers. Axle parallelism has the same negative effect on the tyre wear and road safety as the wheel alignment. For achieving a proper axle parallelism, it is aimed to have all the axles perpendicular to the centre line of the chassis and simultaneously all axles parallel to each other.

In any articulated vehicle, typically, there are three sets of axles, viz. steer axle, drive axle and trailer axle. When one or more of these axles are not parallel or perpendicular to the chassis, excessive and non-uniform wear of the tyre will occur. This may also give a sensation to the drive that the vehicle is pulling to one side.

Therefore, correctly aligned vehicle axles would extend the service-life of the tyres significantly as compared to a vehicle having poorly aligned and maintained vehicle. A proper axle alignment facilitates vehicle handling and driver can control it easily and with confidence and this may also improve fuel economy of the vehicle.

In a properly aligned vehicle, all the axles should be simultaneously perpendicular to the chassis line and parallel to each other, and therefore, all the wheels should track the front wheels.

Axle alignment is necessary to set the wheels and tyres in the optimum position for obtaining maximum tyre performance. Axles are aligned in a static position, so that when the vehicle is operating dynamically, the wheels and tyres are in an optimum position with the road surface, which is when best tyre life and best traction is achieved.

Toe-in is the position in which wheels are closer together in the front than in the back, whereas toe-out is the position in which the wheels are closer together in the back than in the front. Toe-in is necessary to compensate for the steering-component deflection. When driving on the highway with the wheels toe-in, the road friction between the rubber and road pulls the tyres out in a straight direction, which is called as steering deflection. Toe is adjusted in a static condition, for causing the tyres to run in a straight line under a dynamic condition. Most tyre wear is caused by incorrect toe settings.

Toe adjustment is the responsibility of the vehicle manufacturer. Therefore, the axles are made in a parallelogram format and the toe is set at the manufacturing plant itself. The axle manufacturer readily configures a small amount of positive camber into the axle beam and knuckle. However, it has been known that camber is not the most important factor for tyre-wear. Actually, the toe and axle alignment are to be done properly. Trailer axle alignment is a function of three main parameters, i.e. axle-orientation which is adjustable; axle-camber which is non-adjustable; and axle-toe which is non-adjustable.

Axle orientation is defined as the positioning of the axle assembly relative to the vehicle on which it is installed. On a single-axle vehicle, the axle is positioned relative to the vehicle. On a multiple-axle vehicle, the front axle is positioned relative to the vehicle. The remaining axles are positioned such that they are parallel to this front axle.

Front-axle dimensions are measured from the kingpin to the axle center line. If the measurement between “A” and “B” is greater than 3 mm, the forward axle must be adjusted. If the measurement between “A” and “B” is less than 3 mm, the forward axle does not require adjustment.

Rear-axle dimensions are measured from the forward axle center line to the rear axle center line. If the measurement between “C” and “D” is greater than 1.5 mm, the rear axle must be adjusted. If the measurement between “C” and “D” is less than 1.5 mm, then the rear axle does not require adjustment.

DISADVANTAGES WITH THE PRIOR ART

At present, the axle parallelism of the automotive vehicles is set after the vehicle is fully-built. This is the general practice followed everywhere. The presently available gauges for this purpose are very expensive. The handling of the gauges also requires expertise. Once axle parallelism is checked on the testing line and found out to be beyond the permissible limits, the reworking thereof to correct the same is often a very complex and time-consuming job. It also raises serious safety concerns, because it involves applying high torques on U-bolts under the vehicle with serious space constraints for movements thereunder. This is also not acceptable ergonomically. The cost of any such reworking is also substantial, e.g. of the order of approximately Rs.11000/- per month or Rs.79793/- per annum. This has been noticed in 26% of the total cases analysed. Moreover, this activity consumes about 45 minutes for repairing each affected vehicle.

OBJECTS OF THE INVENTION

Some of the objects of the present invention - satisfied by at least one embodiment of the present invention - are as follows:

An object of the present invention is to provide a device for checking and adjusting axle parallelism in multi-axle automobiles.

Another object of the present invention is to provide a device for cost-effective measurement and adjustment of axle parallelism in multi-axle automobiles.

Yet another object of the present invention is to provide a device for facilitating a simple and quick adjustment of axle parallelism in multi-axle automobiles.

A further object of the present invention is to provide an ergonomic method for checking and adjusting axle parallelism in multi-axle automobiles.

Another object of the present invention is to provide a method for checking and adjusting axle parallelism in multi-axle automobiles on the chassis line itself.

Yet another object of the present invention is to provide a method for checking and adjusting axle parallelism in multi-axle automobiles, which reduces operator fatigue.

Still further object of the present invention is to provide a method for checking and adjusting axle parallelism in multi-axle automobiles, which reduces the probability of occurrence of axle parallelism by almost three-fourth.

These and other objects and advantages of the present invention will become more apparent from the following description, when read with the accompanying figures of drawing, which are however not intended to limit the scope of the present invention in any way.

SUMMARY OF THE INVENTION

In accordance with the present invention, there is provided a fixture for setting the wheel axle-parallelism on the automobile chassis line, wherein the fixture comprises:
(i) a pair of tie rod arms;
(ii) a tie rod connected to a tie rod arm disposed on either side thereof through a respective ball joint;
(iii) a pair of curved brackets of reversed configuration and fixed to the respective tie rod arms; and
(iv) a multi-handle lever for facilitating a rotary movement of the tie rod;

wherein graduated scales are provided on a portion on either side of the tie rod for precisely measuring the linear movement between the tie rod arms and tie rod for adjusting the distance between the two tie rod arms for setting axle-parallelism within predetermined limits.

Typically, the handles on the lever are provided circumferentially equidistant.

Typically, the brackets are profiled substantially triangular and provided with a pair of holes on the broad side away from the ball joints for attachment to a respective brake drum on either side of the axle.

Typically, the pair of scales is graduated in the same direction for adjusting the axle parallelism to the predetermined limits.

Typically, the maximum permissible predetermined distance is 3 mm for the forward axles.

Typically, the maximum permissible predetermined distance is 1.5 mm for rear-axles.

In accordance with the present invention, there is also provided a method for checking and setting axle parallelism on the automobile chassis line, wherein the method comprises the steps of:
(a) placing the fixture in between two axles of the vehicle on the same side to be checked for axle parallelism alignment;
(b) inserting the holes of curved brackets into the bolts of the respective brake drums;
(c) adjusting the distance between the tie-rod and tie-rod arm of the fixture – in case the distance does not match the predetermined limits - by rotating the tie rod with the help of handles;
(d) repeating steps (a) to (c) on the opposite side of the same set of axles with another fixture;
(e) measuring the center to center distance of the bolts of both the axles after inserting the fixtures on either side;
(f) marking the distance as ‘X’ on one fixture and as ‘Y’ on the other fixture;
(g) adjusting the distance, if the difference ‘X – Y’ is greater than the predetermined value;
(h) repeating steps (a) to (g) until the distance is within predetermined value;
(i) tightening the U-bolts on both the axles after the respective differences ‘X – Y’ are within the predetermined limits and removing the fixtures from the vehicle.

BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS

The present invention will be briefly described with reference to the accompanying drawings, wherein:

Figure 1a shows the typical camber in the wheel of an automobile;

Figure 1b shows the toe angle in a pair of wheels of an automobile;

Figure 2a shows a set of wheels in an automotive multi-axle trailer, in which axles are set in true axle-parallelism with its chassis;

Figure 2b shows a set of wheels in an automotive multi-axle trailer, in which the axles do not show true axle-parallelism with its chassis;

Figure 3 shows a perspective view of the fixture for setting on the chassis line, the axle parallelism of the chassis in accordance with the present invention used in a multi-axle automobile manufacturing plant;

Figure 4 shows an enlarged view of the left hand portion of the fixture shown in Figure 1;

Figure 5 shows an enlarged view of the central measuring portion of the fixture shown in Figure 1; and

Figure 6 shows a perspective view of an enlarged view of the right hand portion of the fixture shown in Figure 1.

DETAILED DESCRIPTION OF THE ACCOMPANYING DRAWINGS

The fixture for setting the axle parallelism on the vehicle chassis in accordance with the present invention will now be described in more details with reference to the accompanying drawings, without limiting the scope and ambit of the present disclosure in any way. It is important to note that the toe and axle alignment are to be done properly. Any trailer axle alignment is a function of three main parameters: axle orientation; axle camber; and axle toe angle.

Figure 1a shows a typical camber in a wheel of an automobile and thus its effect on the tyre thereof. The axle orientation and axle camber are not adjustable. Therefore, the axle manufacturer already configures a small amount of positive camber into the axle beam and knuckle, visible here.

Figure 1b shows a typical axle toe-angle in a pair of wheels of an automobile. Axle toe-angle is also non-adjustable. Here, the wheels are in toe-in position.

Figure 2a shows a set of wheels in an automotive multi-axle trailer, in which the axles are set in true axle-parallelism with its chassis. Actually, the toe and axle alignment need to be done properly. The four significant components of vehicle alignment are: toe, camber, caster and axle parallelism. Out of these, the axle parallelism is the root-cause of most vehicle alignment problems. Automotive axles are said to be parallel, if the measurement between two or more axles is equal at both ends of the respective axle.

Figure 2b shows a set of wheels in an automotive multi-axle trailer, in which the axles do not show true axle-parallelism with its chassis. Axle parallelism has the same negative effect on the tyre wear and road safety as the wheel alignment.

Figure 3 shows a perspective view of the fixture for setting the axle parallelism on the chassis line and configured in accordance with the present invention. This fixture can be used in a multi-axle automobile. The main components of the fixture are: tie rod arm 2, tie rod 4 with ball joints 6, curved brackets 8, and handle 10. Tie rod 4 also has scales 12 for measurement of the slight amount of linear movement between the tie rod arm 2 and tie rod 4. Accordingly, tie rod 4 is assembled to the tie rod arm 2 through the ball joints 6. Curved brackets 8 are fixed permanently on the tie rod arm 2. So, there is no movement between the tie rod arm 2 and the curved brackets 8. Each curved bracket 8 is also provided with two pairs of holes, by means of which the brackets 8 and thereby the whole fixture can be fixed on the brake drum bolt for checking and trueing the axle parallelism of the automobile.

Figure 4 shows an enlarged view of the left hand portion of the fixture shown in Figure 1. It includes tie rod arm 2 and a part of the tie rod 4 (indicating a portion of the scale 12) connected thereto through a ball joint 6. The curved bracket 8 includes a plurality of holes 14 for inserting the bolts (not shown) of both the brake drums on Tag axle and Live axle respectively.

Figure 5 shows an enlarged view of the central measuring portion of the fixture shown in Figure 1. Here, tie rod arm 2 and tie rod 4 are connected thereto through a ball joint 6. The scale 12 is provided for minor adjustment of the distance by linear movement between tie rod arm 2 and tie rod 4. This is accomplished by means of a rotary movement of the lever 10 provided at the center thereof. The lever 10 is configured as a three-sided handle, which are fixed circumferentially on tie rod 4 and are equispaced apart at 120 degrees with respect to each other.

Figure 6 shows a perspective view of an enlarged view of the right hand portion of the fixture shown in Figure 1. Here also, tie rod arm 2 and a part of the tie rod 4 (indicating a portion of the scale 12) connected thereto through a ball joint 6 are shown. The curved bracket 8 includes a plurality of holes 14 for inserting the bolts (not shown) of both the brake drums on Tag axle and Live axle respectively.

DESCRIPTION OF THE INVENTION

The “axle-parallelism” is the distance to be maintained between the two axles at the time of axle assembly. This parameter is set and checked on appropriate testing line after the vehicle is fully-built. If this parameter is found NOT OK by using the fixture in accordance with the present invention, then by rotating the handles 10 on the tie rod 4, slight linear movement is caused between the tie rod arm 2 and the tie rod 4 to bring the axles in true parallelism. The most important aspect of the present invention is that with this fixture, this parallelism parameter can be checked on the line itself at the time of assembly. If this parameter is found NOT OK by using the fixture in accordance with the present invention, it is possible to easily correct it on the chassis assembly line itself and with very little efforts as compared to the rework on a fully-built vehicle. The method of checking and correcting the axle parallelism in accordance with the present invention is also very operator friendly, being ergonomically superior and thereby it eliminates operator fatigue, which was observed in the earlier methods for checking and trueing the axle-parallelism in automobiles, especially multi-axle automobiles, such as trailers.

METHOD OF USING THE AXLE PARALLELISM FIXTURE

The axle parallelism fixture developed is fixed on the drums of 2 axles. Similar procedure is done on other side. The reading between centre to centre distances of both the axles is taken on both the sides. Difference between these readings should be within pre-specified limits. If this difference is not found within specified limits, then suitable adjustments can be done by rotating the handle or lever provided on the fixture in accordance with the present invention. This rotational movement of the fixture is converted into a linear motion of the tie rod 4, which helps in adjusting the distance to desired limits.

WORKING PRINCIPLE OF THE INVENTION

Accordingly, the new fixture is placed in between the Tag axle and Live axle of the vehicle, on which axle parallelism is required to be checked and corrected. When the vehicle comes on examination stage, the fixture is picked up and inserted into the holes 14 of the curved brackets 8 into the bolts of both the brake drums on Tag axle and Live axle (not shown here).

If the distance doesn’t match the specified limits, it is adjusted by rotating the tie rod 4 with the help of handles on the lever 10. After inserting the fixture, the center to center distance between the bolts of the tag axle and the live axle is measured. This measured distance is marked as ‘X’.

Similarly, after inserting the same fixture on the opposite side and using the same procedure and the distance is marked as ‘Y’. X. Here, Y should be less than or equal to 3 mm. If the difference is more than 3 mm, then there is no axle-parallelism and either of the lengths (distances X or Y) shall be suitably adjusted and the difference is checked again.

This procedure is repeated until obtaining the dimension within the required specified limits, i.e. less than 3 mm here. Once this is achieved, the U-bolts on the axles are tightened and the fixture is removed from the vehicle.

TECHNICAL ADVANTAGES & ECONOMIC SIGNIFICANCE

Some of the technical advantages of the fixture in accordance with the present invention are as under:

- Fixture developed totally in-house and it uses only the parts of vehicle for the purpose of measurement of axle-parallelism and to set true parallelism within desired/specified limits.

- The cost of this fixture is meagre, i.e. approx. Rupees 9000/- as compared to the highly sophisticated and expensive systems offered by various manufacturers.

- The fixture in accordance with the present invention is very easy to use and handle.

- The fixture saves time from earlier 45 minutes for each vehicle, because this checking and adjustment of axle-parallelism can now nbe done on the chassis line itself.

- There is almost zero cost of maintaining the same.

- The fixture is ergonomically superior.

- The fixture causes not operator fatigue, as there is no need for going under the axle/vehicle for checking and correcting axle-parallelism.

- There is no safety concern, as it does not involve application of high torques on U-bolts under the vehicle with space constraints for movements, as was necessary in the earlier system/method.

Throughout this specification the word “comprise”, or variations such as “comprises” or “comprising”, shall be understood to implies including a described element, integer or method step, or group of elements, integers or method steps. However, it does not imply excluding any other element, integer or step, or group of elements, integers or method steps. In the claims and the description, the terms “containing” and “having” are used as linguistically neutral terminologies for the corresponding terms “comprising”.

The use of the expression “a”, “at least” or “at least one” shall imply using one or more elements or ingredients or quantities, as used in the embodiment of the disclosure in order to achieve one or more of the intended objects or results of the present invention. Furthermore, the use of the term “one” shall not exclude the plurality of such features and components described.

The description provided herein is purely by way of example and illustration. The various features and advantageous details are explained with reference to this non-limiting embodiment in the above description in accordance with the present invention.

The descriptions of well-known components and manufacturing and processing techniques are consciously omitted in this specification, so as not to unnecessarily obscure the specification. In the previously detailed description, different features have been summarized for improving the conclusiveness of the representation in one or more examples.

However, it should be understood that the above description is merely illustrative, but not limiting under any circumstances. It helps in covering all alternatives, modifications and equivalents of the different features and exemplary embodiments.

Many other examples are directly and immediately clear to the skilled person because of his/her professional knowledge in view of the above description. Therefore, innumerable changes, variations, modifications, alterations may be made and/or integrations in terms of materials and method used may be devised to configure, manufacture and assemble various constituents, components, subassemblies and assemblies according to their size, shapes, orientations and interrelationships.

While considerable emphasis has been placed on the specific features of the preferred embodiment described here, it will be appreciated that many additional features can be added and that many changes can be made in the preferred embodiments without departing from the principles of the invention. These and other changes in the preferred embodiment of the invention will be apparent to those skilled in the art from the disclosure herein, whereby it is to be distinctly understood that the foregoing descriptive matter is to be interpreted merely as illustrative of the invention and not as a limitation.

The exemplary embodiments were selected and described in order to be able to best represent the principles and their possible practical application underlying the invention. Thereby, the skilled persons can optimally modify and use the invention and its different exemplary embodiments with reference to the intended use. ,CLAIMS:We claim:

1. Fixture for setting the wheel axle-parallelism on the automobile chassis line, wherein the fixture comprises:

(I) a pair of tie rod arms;

(II) a tie rod connected to a tie rod arm disposed on either side thereof through a respective ball joint;

(III) a pair of curved brackets of reversed configuration and fixed to the respective tie rod arms; and

(IV) a multi-handle lever for facilitating a rotary movement of the tie rod;

wherein graduated scales are provided on a portion on either side of the tie rod for precisely measuring the linear movement between the tie rod arms and tie rod for adjusting the distance between the two tie rod arms for setting axle-parallelism within predetermined limits.

2. Fixture as claimed in claim 1, wherein the handles on the lever are provided circumferentially equidistant.

3. Fixture as claimed in claims 1 and 2, wherein the brackets are profiled substantially triangular and provided with a pair of holes on the broad side away from the ball joints for attachment to a respective brake drum on either side of the axle.

4. Fixture as claimed in claims 1 to 3, wherein the pair of scales is graduated in the same direction for adjusting the axle parallelism to the predetermined limits.

5. Fixture as claimed in claims 1 to 4, wherein the maximum permissible predetermined distance is 3 mm for the forward axles.

6. Fixture as claimed in claims 1 to 5, wherein the maximum permissible predetermined distance is 1.5 mm for rear-axles.

7. Method for checking and setting axle parallelism on the automobile chassis line, wherein the method comprises the steps of:

(a) placing the fixture in between two axles of the vehicle on the same side to be checked for axle parallelism alignment;

(b) inserting the holes of curved brackets into the bolts of the respective brake drums;

(c) adjusting the distance between the tie-rod and tie-rod arm of the fixture – in case the distance does not match the predetermined limits - by rotating the tie rod with the help of handles;

(d) repeating steps (a) to (c) on the opposite side of the same set of axles with another fixture;

(e) measuring the center to center distance of the bolts of both the axles after inserting the fixtures on either side;

(f) marking the distance as ‘X’ on one fixture and as ‘Y’ on the other fixture;

(g) adjusting the distance, if the difference ‘X – Y’ is greater than the predetermined value;

(h) repeating steps (a) to (g) until the distance is within predetermined value;

(i) tightening the U-bolts on both the axles after the respective differences ‘X – Y’ are within the predetermined limits and removing the fixtures from the vehicle.

Dated: this 27th January,2015 SANJAY KESHARWANI
APPLICANT’S PATENT AGENT