Claims:We claim:

1. A light-weight, fabricated tow-hook assembly to be tightened on the hauling vehicles for haulage applications, the assembly comprising:

• A pair of profiled vertically disposed metallic side plates having holes for a plurality of fasteners;

• A pair of horizontally disposed metallic profiled hook-plates having a pivot hole each for inserting a pivot bolt; and

• A pivot bolt with a locking means therefor;

wherein the hook-plates are spaced apart, mutually parallel and welded perpendicular to the side plates and after being inserted into the recesses formed in the side plates and the profiles formed on the side-plates and hook-plates are configured to increase the weld area with reduced weight.

2. Fabricated tow-hook assembly as claimed in claim 1, wherein the side plates are rectangular and drilled with a plurality of holes in a predefined pattern for insertion of fasteners there through for tightening the tow-hook assembly on the hauling vehicle.

3. Fabricated tow-hook assembly as claimed in claim 3, wherein each side plate is configured with a profile including a respective recess on the inner face thereof for inserting a respective hook-plate therein before welding of the assembly.

4. Fabricated tow-hook assembly as claimed in claim 3, wherein each side plate is configured with a profile including an extension comprising a plurality of mutually spaced apart cut-outs for increasing the weld area between the side plates and the hook-plates.

5. Fabricated tow-hook assembly as claimed in claim 4, wherein the plurality of mutually spaced apart cut-outs includes a pair of elongated cut-outs for inserting a respective hook-plate therein for welding and a V-cut out of a predefined V-angle formed with the hook plates of the assembly.
6. Fabricated tow-hook assembly as claimed in claim 5, wherein the elongated cut-outs are bent away at predefined angles from the V-cut out, preferably in a mutually opposed direction.

7. Fabricated tow-hook assembly as claimed in claim 1, wherein each hook-plate is configured with an undercut on either side thereof facing the side plate recess for providing additional weld area on the vertical thin face of the side-plate disposed in the direction of haulage.

8. Fabricated tow-hook assembly as claimed in claim 7, wherein the side plate recess is less than or equal to or greater than the hook plate undercut.

9. Fabricated tow-hook assembly as claimed in claim 5, wherein the angle of V-cut is in a range of 30 to 600.

10. Fabricated tow-hook assembly as claimed in claim 6, wherein the angle of bend of the elongated cut-out is in a range of 15 to 450.

Dated: this 31st day of December, 2016. SANJAY KESHARWANI
APPLICANT’S PATENT AGENT , Description:FIELD OF INVENTION

The present invention relates to tow-hook assembly for haulage applications, e.g. in tractors or construction vehicles. In particular, the present invention relates to a tow-hook structure to avoid weld failures. More particularly, the present invention relates to the tow-hook structure with reduced weld stress at lower material costs.

BACKGROUND OF THE INVENTION

The tow-hook assembly is an important feature in most of the tractors or construction vehicles. It is often used for haulage applications. The trailer is pulled by using this tow-hook assembly during any transportation operation. The tow-hook assembly is mounted at the front and/or rear end of the such vehicles. It is normally configured as a fabricated metal structure, in which weld failures frequently occur due to improper fabrication or poor weld quality of the welded structure. This is a major disadvantage with the presently available tow-hook assemblies, which substantially degrades the performance of tractors and/or construction vehicles during such haulage operations.

DISADVANTAGES WITH THE PRIOR ART

The following are the disadvantages with the tow-hook assembly discussed above:
• Higher weld stresses.
• Weld failure due to poor weld quality or improper fabrication.
• Poor performance due to weld failure.
• Higher probability of accident due to weld-failures.
• Higher weight and thus, higher material costs.
• Indirect cost due to warranty related issues.

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 an improved tow-hook assembly for efficient haulage applications.

Another object of the present invention is to provide an improved tow-hook assembly for reducing weld stresses.

Still another object of the present invention is to provide an improved tow-hook assembly for reducing overall manufacturing costs thereof.

Yet another object of the present invention is to provide an improved tow-hook assembly for reducing warranty-related costs incurred due to weld failures.

A still further object of the present invention is to provide an improved tow-hook assembly which reduces accidents during haulage operations.

A yet further object of the present invention is to provide an improved tow-hook assembly which enhances customer satisfaction and earns goodwill for the tow-hook company.

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 light-weight, fabricated tow-hook assembly to be tightened on the hauling vehicles for haulage applications, the assembly comprising:

• A pair of profiled vertically disposed metallic side plates having holes for a plurality of fasteners;

• A pair of horizontally disposed metallic profiled hook-plates having a pivot hole each for inserting a pivot bolt; and

• A pivot bolt with a locking means therefor;
wherein the hook-plates are spaced apart, mutually parallel and welded perpendicular to the side plates and after being inserted into the recesses formed in the side plates and the profiles formed on the side-plates and hook-plates are configured to increase the weld area with reduced weight.

In an embodiment of the present invention, the side plates are rectangular and drilled with a plurality of holes in a predefined pattern for insertion of fasteners there through for tightening the tow-hook assembly on the hauling vehicle.

In another embodiment of the present invention, each side plate is configured with a profile including a respective recess on the inner face thereof for inserting a respective hook-plate therein before welding of the assembly.

In still another embodiment of the present invention, each side plate is configured with a profile including an extension comprising a plurality of mutually spaced apart cut-outs for increasing the weld area between the side plates and the hook-plates.

In yet another embodiment of the present invention, the plurality of mutually spaced apart cut-outs includes a pair of elongated cut-outs for inserting a respective hook-plate therein for welding and a V-cut out of a predefined V-angle formed with the hook plates of the assembly.

In a further embodiment of the present invention, the elongated cut-outs are bent away at predefined angles from the V-cut out, preferably in a mutually opposed direction.

In still further embodiment of the present invention, each hook-plate is configured with an undercut on either side thereof facing the side plate recess for providing additional weld area on the vertical thin face of the side-plate disposed in the direction of haulage.

In yet further embodiment of the present invention, the side plate recess is less than or equal to or greater than the hook plate undercut.

According to an additional embodiment of the present invention, the angle of V-cut is in a range of 30 to 600.

According to another additional embodiment of the present invention, the angle of bend of the elongated cut-out is in a range of 15 to 450.

BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS

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

Figure 1a shows a conventional tow-hook structure for haulage applications.

Figure 1b shows the enlarged encircled weld joint region of Figure 1a, plotted with Von-Mises stress contour therein.

Figure 1c shows another conventional tow-hook structure configured with cut outs on the side plates for inserting hook plates before welding thereof.

Figure 2a shows a first embodiment of the tow-hook assembly 100 configured in accordance with the present invention for various haulage applications.

Figure 2b shows a fabricated structure mounted with the tow-hook assembly of Figure 2a, however without the center pin.

Figure 2c shows an enlarged view of the Von-Mises stress plot for the encircled weld joint region of the tow-hook structure of Fig. 2b.

Figure 3 shows a second embodiment of the tow-hook assembly in accordance with the present invention configured with V-cut outs on the side plates and provided with inward bending thereof before welding on the hook plates.

Figure 4a shows detailed perspective view of conventional tow-hook structure.

Figure 4b shows a front view of the tow-hook structure of Fig. 4a depicting two side plates and two mutually parallel hook-plates.
Figure 4c shows a top view of the tow-hook structure of Fig. 4a.

Figure 5a shows a perspective view of a third embodiment of the tow-hook structure configured in accordance with the present invention.

Figure 5b shows a front view of the improved tow-hook structure of Fig. 5a depicting two side plates and two mutually parallel hook-plates.

Figure 5c shows a top view of the tow-hook structure of Fig. 5a.

Figure 5d shows a perspective view of hook plates provided with a rear edge recess and a hook plate side edge notch encircled in the region thereof.

Figure 5e shows enlarged view of the hook plate with side notch of depth ‘d1’.

Figure 5f shows enlarged view of the side plate having a recess of depth ‘d2’.

Figure 6 shows a perspective view of the fabricated structure welded with the conventional tow-hook assembly of Figure 1b.

Figure 7a shows a perspective view of the fabricated structure welded with the second embodiment of a tow-hook assembly provided with V-cut in side plates.

Figure 7b shows an enlarged perspective view of the tow-hook assembly of Figs.5a-5c and depicting the (transparent) hook plates welded in the recess of the side plates.

Figure 7c shows another perspective view of the tow-hook assembly of Figs.5a-5c depicting the side plates provided with the recess.

Figure 8a shows a detailed perspective view of first type of V-cut of Fig. 6b.

Figure 8b shows a detailed perspective view of second type of V-cut of Fig.6b.

Figure 8c shows a detailed perspective view of the third type of V-cut of Fig.6b.

Figure 9a shows a detailed perspective view of the first type of the inwardly bend cut-outs of Figure 6b.

Figure 9b shows a detailed perspective view of the second type of the inwardly bend cut-outs of Figure 6b.

Figure 9c shows a detailed perspective view of the third type of the inwardly bend cut-outs of Figure 6b.

Figure 10a shows the front and side views of the side hook side plate having V-cuts made in accordance with the present invention.

Figure 10b shows an enlarged perspective view of the tow-hook assembly of Figure 7a.

Figure 11a shows a perspective view of the fabricated tow-hook structure of Figure 8a-8c.

Figure 11b shows an enlarged view of the fabricated tow-hook structure of the tow-hook depicted in Figures 11a.

Figure 12a shows a perspective view of the fabricated structure of the tow-hook of Figure 9a-9c.

Figure 12b shows an enlarged view of the encircled weld joint region of Fig.12a.

Figure 13a shows a graphical representation of the stress reduction with the angle of V-cut for the fabricated tow-hook structure configured in accordance with the present invention.

Figure 13b shows a graphical representation of the stress variation with the depth cut for the fabricated tow-hook structure configured in accordance with the present invention.

Figure 13c shows a graphical representation of the stress variation with the angle of bend for the fabricated tow-hook structure configured in accordance with the present invention.

DETAILED DESCRIPTION OF THE ACCOMPANYING DRAWINGS

In the following, the improved the fabricated tow-hook structure configured in accordance with the present invention will be described in more details with reference to the accompanying drawings without limiting the scope and ambit of the present invention in any way.

Figure 1a shows a conventional tow-hook structure for haulage applications. The fabricated structure is mounted with the tow-hook assembly 02 of Figure 1a, however without the center pin 24 (which is removed here for hauling an equipment) passing through the apertures 22 in the hook plates 20. The tow-hook assembly 10 is mounted on the structure 30 by fasteners (not shown) tightened through the side plates 10. The encircled weld joint region 40 is studied in detail by plotting Von-Mises stress contour, which is shown in Figure 1b. The disadvantage with this configuration of the tow-hook assembly is the poor performance of the tractor occurring due to occurrence of weld failures in the fabricated structure. The weight of the assembly is also high, which leads to higher overall cost of the tractors. Frequent weld failure also cause higher warranty related costs and loss of customer satisfaction.

Figure 1b shows the enlarged encircled weld joint region 40 of Figure 1a, plotted with Von-Mises stress contour therein. The weld joint region 40 has Von-Mises stress of 380 MPa in the red-marked point 42 thereof.

Figure 1c shows another conventional tow-hook structure configured with straight cut outs 62 on the side plates 60 for inserting hook plates 20 before welding thereof. Here, Von-Mises stress in the hook plates is observed to be about 595 MPa. The weld joint region 50 has Von-Mises stress of 595 MPa in the red-marked point 52 in the encircled region 50 thereof.

Figure 2a shows a first embodiment of the tow-hook assembly 100 configured in accordance with the present invention for various haulage applications. This improved tow-hook assembly 100 is configured to reduce the weld stress therein. The tow-hook assembly consists of a fabricated structure comprising a pair of rectangular side plates 110 provided with a plurality of apertures 112 welded to a pair of hook plates 120 mutually spaced and disposed in a plane perpendicular to the side plates 110 by means of a respective profiled rib 114 at either end thereof. A center pin 122 passes through the apertures 124 provided in the hook plates 120. The center pin 122 is locked by means of a locking pin 126 after placing the trailer for hauling it, duly locked in the tow-hook assembly 100 at the front or rear of the tractor. It is observed through plotting of Von-Mises stress that the encircled weld region 140 is exposed to highest loads during haulage applications and it has substantially lower values than the conventional tow-hook assembly shown in Fig. 1b.

Figure 2b shows a fabricated structure mounted with the tow-hook assembly 100 of Figure 2a, however without the center pin 122 (which is removed here for inserting the eye bolt of the equipment to be locked before hauling it) through the hook plates 120. The tow-hook assembly 100 is mounted on the structure 130 by fasteners (not shown) through the side plates 110. The encircled weld joint region 140 is studied in detail by plotting Von-Mises stress contour shown in Figure 2c.

Figure 2c shows an enlarged view of the Von-Mises stress plot for the encircled weld joint region 140 of the tow-hook structure 100 of Fig. 2b. The encircled weld joint region 140 shows a Von-Mises stress of 275 MPa in the red-marked point thereof. Therefore, weld stress is reduced by up to 28% in the weld joint region or weld zone to earn customer satisfaction and reduce warranty claims.

Figure 3 shows a second embodiment 200 of the tow-hook assembly configured in accordance with the present invention provided with V-cut outs on the side plates 210 and provided with inward bending 218 before welding of the hook plates 220. However, Von-Mises stress in the encircled weld-joint region 250 at the red-marked point 252 thereof is observed to be about 359 MPa, which is about 40% less than the conventional straight cut-outs of Fig.1c.

Figure 4a shows a detailed perspective view of the conventional tow-hook structure 04. Here, inner faces of the side plates 10 are made flush with the hook plates 20 before welding. Here, the weld thickness is increased to avoid stresses in the weld zone or additional ribs are provided therefor which increases the overall material cost of the tow-hook assembly.

Figure 4b shows a front view of the tow-hook structure of Fig. 4a depicting two side plates 10 and two mutually parallel hook-plates 20 perpendicular to the side plates 10 and fixed there between.

Figure 4c shows a top view of the tow-hook structure 04 of Fig. 4a. The hook-plates 20 are mutually parallel and fixed between the side plates 10. Here, the hook plates 20 have a rear edge recess 28 to avoid fouling thereof with the PTO housing.

Figure 5a shows a perspective view of a third embodiment of the tow-hook structure 300 configured in accordance with the present invention. It also includes two side plates 310 and two mutually parallel hook-plates 320 perpendicular to the side plates 310 and fixed inside the grooves 314 for avoiding increased weld thickness or omitting additional ribs normally required in the conventional tow-hook assembly discussed above. This also reduces the overall weight and thereby the final material cost of this improved tow-hook assembly. The recess 314 are made in the inner faces of the side plates 310 for retaining the hook plates 320 in place.

Figure 5b shows a front view of the improved tow-hook structure of Fig. 5a depicting two side plates 310 and two mutually parallel hook-plates 320perpendicular to the side plates 310.

Figure 5c shows a top view of the tow-hook structure 300 of Fig. 5a. The hook-plates 320 are disposed mutually parallel and fixed between the side plates 310 inside the notches 314. The hook plates 320 have a recess 328 (to avoid the front end lifting of the tractor) on one side at the rear edge thereof and an aperture 324 at the center for passing the center pin 322 there through. Thus, incorporating the recess 328 helps in avoiding fouling issues with the PTO housing. Here, the hook plates 320 also have a side edge notch 318 and a rear edge recess 328 on a side thereof. The feature (recess 328 helps in avoiding the fouling issues with PTO housing when there was an inward shift of tractor hitch point from RAC). The hitch location of tow hook assembly from RAC is shifted inside by 115mm.

Figure 5d shows a perspective view of the hook plates 320 discussed in Figures 5b-5c, each provided with a rear edge recess 328 and a hook plate side edge notch 318 encircled in the region 350 thereof.

Figure 5e shows an enlarged view of the hook plate 320 of Figures 5b-5c depicted with a side notch 318 of depth ‘d1’ by which the hook plate 320 can be inserted into the side plate recess 314 (not shown here) before the welding between the side plate 310 and hook plates 320.

Figure 5f shows an enlarged view of the side plate 310 having a recess 314 of depth ‘d2’ in which the hook plate 320 can be inserted before the welding between the side plate 310 and hook plates 320.

Figure 6 shows a perspective view of the fabricated structure 30 welded with the conventional tow-hook assembly 06 of Figure 1c and having side plate 60 provided with straight cut-outs 62 for inserting the hook plates 20.

Figure 7a shows a perspective view of the fabricated structure welded with the second embodiment of the tow-hook assembly 200 provided with V-cut 216 in the side plates 210 and inwardly bend cut-outs 218 as shown in Figure 3.

Figure 7b shows an enlarged perspective view of the tow-hook assembly of Figs.5a-5c and depicting the (transparent) hook plates 320 welded after insertion in the recess 314 of the side plates 310.

Figure 7c shows another perspective view of the tow-hook assembly of Figs.5a-5c depicting the side plates 310 provided with the recess 314 for inserting the hook plates therein before welding.

Figure 8a shows a detailed perspective view of the first type of V-cut 216 of Figure 7a having and angle of cut of 300.

Figure 8b shows a detailed perspective view of the second type of V-cut 216 of Figure 7a having and angle of cut of 450.

Figure 8c shows a shows detailed perspective view of the third type of V-cut 216 of Figure 7a having and angle of cut of 600.

Figure 9a shows a detailed perspective view of the first type of the inwardly bend cut-outs 218 of Figure 7a having and angle of bend of 150.

Figure 9b shows a detailed perspective view of the second type of the inwardly bend cut-outs 218 of Figure 7a having and angle of bend of 300.

Figure 9c shows a detailed perspective view of the third type of the inwardly bend cut-outs 218 of Figure 7a having and angle of bend of 450.

Figure 10a shows a front view of the side hook side plate 210, 310 with V-cut 216, 316 making an angle a and having depth of L from the base of recess 216, 316 therein. The figure also shows a top view of the side plate 210, 310 with inward bend 218, 318 making an angle ß with the straight face thereof.

Figure 10b shows an enlarged perspective view of the tow-hook assembly of Figure 7a.

Figure 11a shows a perspective view of the fabricated tow-hook structure of Figure 8a-8c. Von-Mises stress plot of the encircled weld joint region 260 is shown in Figure 11b.

Figure 11b shows an enlarged view of the fabricated tow-hook structure of the tow-hook depicted in Figures 11a depicting the region 260 with high Von-Mises stress therein, i.e. in the weld joint 262 between the hook plate 220 and the inward bend 218, which has maximum weld stress of 273 MPA, i.e. substantially lower than any of the conventional tow-hook assemblies.

Figure 12a shows a perspective view of the fabricated structure of the tow-hook of Figure 9a-9c, depicted from the bottom side thereof. Von-Mises stress plot of the encircled weld joint region 270 is shown in Figure 12b.

Figure 12b shows an enlarged view of the encircled weld joint region 270 of Figure 12a, i.e. in the weld joint 272 between the hook plate 220 and the inward bend 218, which has maximum weld stress of 223 MPA, i.e. substantially lower than any of the conventional tow-hook assemblies.

Figure 13a shows a graphical representation of the stress reduction with the angle of V-cut for the fabricated tow-hook structure configured in accordance with the present invention.

Figure 13b shows a graphical representation of the stress variation with the depth cut for the fabricated tow-hook structure configured in accordance with the present invention.

Figure 13c shows a graphical representation of the stress variation with the angle of bend for the fabricated tow-hook structure configured in accordance with the present invention.

WORKING OF THE INVENTION

The present invention facilitates to avoid weld failures in fabricated structures. This tow hook assembly is a structural member used for pulling the trolleys / trailers during transportation operation. It acts as a connecting member between the tractor and trailer thus playing a major role in haulage application of tractors.
While the tractor takes a turn, the V-cut outs provided in the tow-hook assembly facilitates in a free rotation of the trailer and the depth of cuts provided on plates (side plate recesses and or hook plate undercuts) helps in reducing (by almost 40%) the weld stress developed at the weld zones. Bent side pates also helps in avoiding the usage of additional ribs required in conventional designs.

TECHNICAL ADVANTAGES AND ECONOMIC SIGNIFICANCE

The improved the fabricated tow-hook structure configured in accordance with the present invention has the following technical and economic advantages:

• Stepped support, inward bending and V-cut substantially reduces weld stress.

• Low-weight.

• Reduced weld-thickness substantially reduces the material cost.

• Fabricated structure reduces the overall cost.

• Enhances tractor performance.

• Avoids weld-failures.

• Improved structural stiffness.

• Easy in manufacturability.

• Free lateral rotation of trailer.

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, does not imply excluding any other element, integer or step, or group of elements, integers or method steps.

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.
The exemplary embodiments described in this specification are intended merely to provide an understanding of various manners in which this embodiment may be used and to further enable the skilled person in the relevant art to practice this invention. The description provided herein is purely by way of example and illustration.

Although the embodiments presented in this disclosure have been described in terms of its preferred embodiments, the skilled person in the art would readily recognize that these embodiments can be applied with modifications possible within the spirit and scope of the present invention as described in this specification by making innumerable changes, variations, modifications, alterations and/or integrations in terms of materials and method used to configure, manufacture and assemble various constituents, components, subassemblies and assemblies, in terms of their size, shapes, orientations and interrelationships without departing from the scope and spirit of the present invention.

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.