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| United States Patent | 3,890,696 |
| Buske | June 24, 1975 |
Tow truck boom and method of constructing same
Abstract
A tow truck includes a pair of booms comprised of two identical channel-shaped members being secured together in face-to-face relationship to form a space therebetween. Each of the members includes serrations in the side walls in a common transverse plane at the center of the boom and the serrations are closed by weldments. The boom is constructed by taking a blank sheet of rectangular material and shaping it to taper it from the transverse center to the outer ends along all of its edges and providing inwardly shaping V-shaped notches along the transverse centerline. Side walls are then formed by bending and then the resulting two channel-shaped members are placed in edge-to-edge engagement along one end and held in this position by welding while the opposite ends are drawn together such that bending occurs in a plane through the vertexes of the V-shaped notches and the notches are closed. All abutting edges are then welded together to complete the boom.
| Inventors: | Buske; Earl R. (Pocahontas, IA) |
| Appl. No.: | 05/359,104 |
| Filed: | May 10, 1973 |
| Current U.S. Class: | 228/173.6 ; 228/155; 29/897.2 |
| Current International Class: | B21D 47/00 (20060101); B21D 47/01 (20060101); B23K 9/00 (20060101); B60P 3/28 (20060101); B66C 23/64 (20060101); B66C 23/00 (20060101); B23k 031/06 () |
| Field of Search: | 29/471.1,475,482,484,155C 156/211 113/116A,116W,116HH |
| 1694430 | December 1928 | Root |
| 2418312 | April 1947 | Michelman |
| 3039414 | May 1962 | Rosanes |
| 3762448 | October 1973 | Donohue |
Assistant Examiner: Hampilos; Gus T.
Attorney, Agent or Firm:
I claim:
1. Method of constructing a boom having a cross sectional area that increases from the opposite ends towards the center comprising the steps of,
providing a pair of channel-shaped members in face-to-face relationship wherein each channel member includes side walls which increase in height from the outer ends of the members towards the center and a V-shaped notch is provided at the center of each side wall, said notch having its vertex at the base of the channel,
bending of the base of each of said members along a fold line extending across the base of each member and through the vertexes of said V-shaped notches to bring said members into engagement along the edges of their adjacent side walls, and
bonding together the adjacent edges of said members.
2. The method of claim 1 wherein said bonding of said adjacent edges of said members is further defined as being welding.
3. The method of claim 1 wherein the bending of each of said members is further defined as including first placing the adjacent edges of adjacent ends of said members in engagement with each other and then holding said adjacent ends while the opposite ends are drawn together causing said members to be bent along said fold line.
4. The method of claim 1 wherein said providing of said pair of channel members is further defined as including the steps of first providing a pair of rectangular blank sheets, tapering the blank sheets along opposite side edges in opposite directions from the transverse centerline towards the outer ends, and then bending the sheets to form said channel-shaped members.
5. The method of claim 4 wherein the steps of forming said V-shaped notches is performed prior to bending the sheets to form said channel members.
A wrecker truck will usually include two boom members. These members must be rugged and strong as they are the backbone of the wrecker equipment. At the same time they must be aesthetically attractive and have eye appeal. They should also be smooth to allow for ease of cleaning and painting. To overcome the tendency of the boom members to buckle in the center, they may be beefed up in the center area by that area being larger in cross section than the outer ends. To produce a boom-shaped member having a nonuniform cross section requires special construction procedures.
The boom of this invention is easily fabricated with a minimum expenditure of time and materials. The boom member is square in cross section throughout its length but increases in cross section from the outer ends toward a transverse center plane. Two channel members are first formed and notches are provided in the side walls at the transverse center plane such that when the ends of the channel members are bent towards each other the V-shaped notches are closed and the side wall edges move into engagement whereupon they are welded to provide a totally enclosed boom. Thus, although the boom is nonuniform in cross section throughout its length it nevertheless is constructed from only two separate members.
This invention consists in the construction, arrangements and combination of the various parts of the device, whereby the objects contemplated are attained as hereinafter more fully set forth, specifically pointed out in the claims, and illustrated in the accompanying drawings in which:
FIG. 1 is a perspective view of a wrecker truck utilizing the boom members of this invention.
FIG. 2 is a top plan view of a blank sheet of metal material shaped for construction of the boom.
FIG. 3 is a side elevational view of the blank sheet of material after the bending step wherein channel side walls have been formed.
FIG. 4 is a later side elevational view wherein the two channel-shaped members are placed in facing relationship with a pair of adjacent ends being held together while the opposite ends are separated.
FIG. 5 is a further side elevational view after the opposite ends of the channel members are drawn together and secured by welding; and
FIG. 6 is a top plan view taken along line 6--6 in FIG. 5.
FIG. 7 is a cross sectional view taken along line 7--7 in FIG. 6.
The boom members of this invention are referred to generally in FIG. 1 by the reference numeral 10 and are shown on a truck 12 having wrecker equipment 14 thereon.
It is seen that the boom members 10 are not uniform in cross section along their length having their biggest cross section at the center and the cross section decreases towards the opposite ends thereof. The boom is hollow throughout its entire length and comprises only two separate elements, two channel-shaped members 16 and 18 as seen in FIG. 4.
Each of the channel-shaped members are identical and are formed following the same method steps. First a blank sheet of rectangular in shape material is shaped to provide the configuration in FIG. 2 wherein the side edges 20 all taper from a transverse center fold line 22 towards the outer ends 24. Inwardly extending V-shaped notches 26 are provided on the transverse centerline 22 such that when the channel side walls 28 of FIG. 3 are formed by bending the V-shaped notches extend from the outer side wall edges to the base portion 30 of the channel-shaped member. Next, the two channel-shaped members are placed in facing relationship as seen in FIG. 4 with one pair of ends engaging each other along the side wall edges and weldments 32 are utilized for securing the adjacent ends 32 together. Next, the opposite ends 34 are drawn together resulting in the V-shaped notches being closed as seen in FIG. 5 and the outer edges of the side walls 28 moving into engagement with each other identical to the ends 32 and weldments 31 are also employed to hold the ends 34 together. The result of these steps is a completed boom 10 as seen in FIG. 6 formed from only two pieces of material and being square in cross section and hollow throughout its length while having a cross section which increases from the outer ends toward the transverse center which is in a plane through the vertexes of the V-shaped notches 26 and on the foldlines 22. This provides the maximum strength in the center where it is needed and also provides a boom member having aesthetically appealing lines. All abutting edges are secured together by weldments.
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