Boom construction and method for making same

• US 4,034,876 A
• Filed: 04/23/1975
• Issued: 07/12/1977
• Est. Priority Date: 05/28/1974
• Status: Expired due to Term

• Current Assignee: Caterpillar Incorporated
• Original Assignee: Caterpillar Americas Company (Caterpillar Incorporated)
• Inventors: Yancey, John W.
• Primary Examiner(s): Makay, Albert J.
• Assistant Examiner(s): Weaver, Ross
• Application Number:
  US05/570,985
• Time in Patent Office: 811 Days
• Field of Search: 214/145 R, 214/138 R, 214/152, 212/144, 52/730
• US Class Current: 29/897.2
• CPC Class Codes: E02F 3/32 working downwardly and towards the machine, e.g. with backhoes
• CPC Class Codes: E02F 3/38 Cantilever beams , i.e. booms;, e.g. manufacturing processes, forms, geometry or materials used for booms for booms with cable suspension arrangements E02F9/14 takes precedence; Dipper-arms , e.g. manufacturing processes, forms, geometry or materials used for dipper-arms; Bucket-arms E02F3/34 takes precedence
• CPC Class Codes: Y10T 29/49616 Structural member making
• CPC Class Codes: Y10T 29/49622 Vehicular structural member making

Abstract

An excavator boom has attachment means formed on opposite ends thereof for attachment to a vehicle and to a work implement. The boom comprises a pair of continuous and uninterrupted upper and lower plates and a pair of side plates, all secured together by four continuous welds to form a box section throughout the length of the boom. The boom is generally V-shaped and has a third attachment means formed at the apex thereof. During fabrication of the boom, the various plates and attachment means are positioned in suitably arranged fixtures and are tack welded together. The boom is then placed on each of its sides for final welding purposes.

Claims

1. A method for making a boom comprising the steps of,

first cutting and shaping a pair of substantially identical upper and lower plates and a pair of substantially identical side plates,

forming openings in the side plates for receiving pivot bell castings therein,

joining a pair of pivot bell castings, having annular axial flange means and radial flange means which include a portion arranged to abut the inner surface portions of the side plates, by joining said annular axial flange means to respective ends of a cylindrical connecting member,

then welding the side plates to the radial flange means of said bell casting assemblies,

then tack welding one leg of an angle bar to the edges of the side plates so that each angle bar projects above said edges a predetermined amount for defining the width of subsequent lateral welds joining said side plates to upper and lower plates abutted thereagainst and for providing a backup member for such welds,

then positioning the assembly so formed on a lower plate and tack welding the assembly to the lower plate with the other legs of the angle bars abutting the lower plate,

thereafter positioning an upper plate on the top lateral edges of the side plates, also in abutting relationship with the other legs of the angle bars, and tack welding the upper plate to the assembly,

then turning the tack welded assembly on a first side plate and completing an annular weld of one bell casting to the other side plate and securing the upper and lower plates to said other side plate,

thereafter turning the assembly on to said other side plate and completing an annular weld of the other bell casting to the first side plate and securing the upper and lower plates to the first side plate.

2. The method of claim 1 wherein each of said first and second securing steps comprises securing an apex of a respective weld means to a respective angle bar.

3. The method of claim 1 wherein each of said side plates are pre-fabricated by securing a pair of co-planar first and second plates together by a weld disposed transversely relative to said side plates.

4. The method of claim 3 further comprising the steps of pre-forming said first plate with a wall thickness greater than the wall thickness of said second plate and forming an end portion of the length of said first plate adjacent to said second plate with a wall thickness substantially matching the wall thickness of said second plate.

5. The method of claim 1 further comprising the steps of securing an attachment means on each end of said boom.

6. The method of claim 1 further comprising the steps of pre-forming each of said plates into a V-shape to comprise a boom which is generally V-shaped when viewed in side elevation and securing an attachment means at an apex of said boom.

7. The method of claim 5 further comprising pivotally mounting said boom on a frame of a vehicle at one of said attachment means and attaching said boom to a work implement at the other one of said attachment means.