TITLE OF THE INVENTION: STRUCTURAL ADHESIVE APPLICATION METHOD FOR THE HOOD AND FENDER ASSEMBLY OF AGRICULTURAL VEHICLES

FIELD OF THE INVENTION
The present invention relates to a structural adhesive application method for the hood and fender assembly of agricultural vehicles.

BACKGROUND
Conventionally, the hood and fender assembly panels in agricultural vehicles such as tractors are made up of sheet metal using welding processes. But the welding processes affect the surface quality of these panels, which are of aesthetic importance. To retain the aesthetic quality, presently, structural adhesives are used as an alternative joining process. Generally, these adhesives are hot cured during paint processes. These panels are generally welded in a weld shop and transferred to a paint shop. To facilitate this transit from the weld shop to the paint shop, these panels are generally locally welded. Local welding gives sufficient handling strength till the assembly goes into a curing oven at the paint shop.

There are three main problems in the conventional practice. The first is the curing of the adhesives requires the presence of a curing oven in the weld shop; this occupies space and is also very expensive. The second is the local welding requirement, which ruins the aesthetic quality of the components. Third, the adhesives are cured at room temperature in the welding shop. At room temperature, it will take approximately 24 hours to cure. The production rate does not permit slow curing. It will be apparent to a person skilled in the art that curing can be accelerated by heating through installing a baking oven. However, this is very expensive, and affects the existing welding shop layout and occupies more space.

There is therefore a need in the art for a structural adhesive application method for the hood and fender assembly of agricultural vehicles that overcomes the above mentioned drawbacks and has the below mentioned objectives.

OBJECTIVES OF THE INVENTION

An objective of the present invention is to provide a cost-effective process of applying structural adhesives to effectively bond the hood and fender assembly of agricultural vehicles without affecting the aesthetic quality of an agricultural vehicle's exterior.

Another objective of the present invention is to provide a structural adhesive application method in which the curing process is accelerated without affecting present weld shop layout and without compromising on the production rate.

SUMMARY OF THE INVENTION
To overcome the drawbacks of the prior art and accomplish the above mentioned objectives, a novel structural adhesive application method is disclosed. In accordance with the present invention, infrared (IR) heating units are installed on portable stand(s). As a result, the curing process is accelerated and is thus amenable to fast production. Further, the existing weld shop layout and the aesthetics of the vehicle's exterior are not affected.

BRIED DESCRIPTION OF THE DRAWING
Figure 1 shows an embodiment of the structural adhesive application method the hood and fender assembly of agricultural vehicles, in accordance with the present invention.

DETAILED DESCRIPTION OF THE DRAWING
An embodiment of the structural adhesive application method is illustrated in Figure 1. After making the individual parts (the hood and the fender), the hood and fender assembling process will takes place. The first step in the process is cleaning and degreasing (101). In this step, the inner and outer surfaces of the hood and the fender are cleaned properly by removing grease, dust, dirt etc. from their surface. After the completion of cleaning and degreasing (101), the hood and the fender are loaded into fixtures (102) and then clamped together (103). After clamping (103), a structural adhesive is applied (104) on a predetermined place ;for coupling them together permanently. The structural adhesive used here is preferably amepoxy based two component adhesive. The next step after applying the adhesive is the curing process. In general, curing of the adhesive takes a minimum of 24 hours in room temperature (23 degrees Centigrade). The structural adhesive that is used here is fast curable by means of heating (preferably at 80 degree Centigrade). For accelerating the curing process, one or more infrared heating units (105) are installed on one or more portable stands, due to which, the assembly can be heated at a faster rate. This infrared curing process reduces the curing time significantly from 24 hours to 2-3 minutes, thus increasing the production rate. Additionally, the installation of the portable infrared heating units (105) does not affect the weld shop layout. Preferably, wheel mounted infrared heating units are used. This kind of structural adhesive coupling eliminates the requirement of welding and ensures the aesthetic quality of the fender and hood assembly is retained. After completion of the curing process, the coupled component parts are removed from clamping
and fixtures and shipped (106) to the paint shop. In the paint shop, prime painting (107) on the coupled components is done. Before completing painting on the top and back (109), drying of primer paint (108) is done.

While the disclosed method is applicable to all agricultural vehicles with a hood and fender ; assembly, it is preferred that the agricultural vehicle is a tractor.

It will be apparent to a person skilled in the art that the above description is for illustrative purposes only and should not be considered as limiting. Various modifications, additions, alterations, and improvements without deviating from the spirit and the scope of the invention ) may be made by a person skilled in the art.

We claim:

1. A structural adhesive application method for a hood and fender assembly of an agricultural vehicle, comprising the steps of:

making a hood and a fender;

cleaning and degreasing (101) the inner and outer surfaces of the hood and the fender;

loading the hood and the fender into fixtures (102);

clamping (103) the hood and the fender together;

application of a structural adhesive (104) at a predetermined place for permanent coupling of the hood and the fender, wherein the structural adhesive coupling eliminates the requirement of welding and thus does not affect the agricultural vehicle's exterior appearance;

curing of the structural adhesive, wherein one or more infrared heating units installed on one or more portable stands are utilized for accelerating the curing process which significantly reduces the curing time;

removing coupled hood and fender from clamping and fixtures and shipping (106) to a paint shop;

prime painting (107) on the coupled hood and fender;

drying of primer paint; and

top coat painting on the top and back of the coupled hood and fender.

2. The structural adhesive application method as claimed in claim 1, wherein the structural adhesive used is an epoxy based two component adhesive.

3. The structural adhesive application method as claimed in claim 1, wherein the one or more infrared heating units used are wheel mounted infrared lamps.

4. The structural adhesive application method as claimed in claim 1, wherein the curing time of the structural adhesive is in the range of 2-3 minutes.

5. The structural adhesive application method as claimed in claim 1, wherein temperature of the curing process is 80° C.

6. The structural adhesive application method as claimed in claim 1, wherein the agricultural vehicle is a tractor.