Patent Application
20220297222
The present invention relates to joining of metal objects by thermal welding, including arc, heliarc, oxyacetylene, and the like; more particularly, to butt welding of metal plates; and most particularly, to a ceramic shelf assembly removably attachable to the front side of one of two adjacent weldable metal plates to prevent liquid weld material from overflowing a weld joint onto the front surface of one of the plates during formation of the weld joint.
The present invention is directed to the art of thermal welding as by arc, heliarc, oxyacetylene, and the like.
In butt welding of adjacent plates or sheets of metal, and especially steel, one of the plates is provided with a square-cut end, referred to as a square edge, and the other plate is provided with a chamfered end, referred to as a bevel edge, thereby forming a V-shaped groove, also known as a single-bevel groove, for accumulation of molten welding material over the entire thickness of the plates. Each plate may be thought of as having a back side and a front side, and welding proceeds from the back corners or edges of the groove to the front corners or edges. The groove may be positioned on the underside of the plates (“overhead”); on the top side of the plates; in a vertical orientation on a wall; or in a horizontal orientation on a wall. In all such orientations except the last one, a welding joint may be finished by an expert welder with no welding material overflowing onto the face of either plate.
However, a problem arises in welding a horizontal groove between adjacent plates disposed vertically. In such a groove, the lower plate is provided with a square butt end, while the upper plate is chamfered or beveled as described hereinabove. As the groove filling nears completion, liquid weld material can easily and undesirably overflow the corner of the lower plate under gravity and solidify on the plate surface. Typically, such solidified material must be ground off in a further step which is wasteful of time, labor, and material.
In the prior art, there are numerous patents dealing with prevention of liquid material from flowing from the back side of a weld joint during the start of welding thereof. See, for example, U.S. Pat. No. 3,972,466 to Keith which discloses a welding back-up strip that incorporates woven carbon filter cloth and a pressure-sensitive adhesive layer attachable to the back sides of the adjacent plates. The cloth strip is adhered to the backs of adjacent work pieces across the back of the channel to be filled, and the work pieces then are butt welded. See also for example, U.S. Pat. No. 4,049,183 to Roden et al. which discloses a welding back-up tape utilizing a small diameter, heavy wall, flexible woven refracting filter tube within a slightly larger diameter tube. Both of the tubes are partially flattened against an adhesive coated surface of the wider heat resistant tape.
Several other patents also deal with preventing leakage of liquid weld material from the back side of the groove, but there is believed to be no prior art dealing with the front side problem described hereinabove.
What is needed in the art is a method and apparatus for reliably preventing such overflow from occurring on the front side of the weld, leaving a smooth transition between the weld reinforcement known as the cap or cover pass to the base metal joined, finished front side to the welded joint.
Provided is a ceramic shelf assembly for aiding formation of a butt weld of adjacent metal plates in a groove formed between adjoining plates. The assembly has at least one ceramic block having at least one straight edge. The assembly further provides an apparatus for removably attaching the rear side of the ceramic block to a front surface of one of the adjacent metal plates along an edge of the groove.
More precisely, the present invention is directed to a welding aid in the form of a ceramic shelf assembly attachable to the front side of one of two adjacent weldable metal plates, e.g., steel, aluminum, or other metals or alloys, to prevent liquid weld material from overflowing a weld joint during formation thereof. The present invention is especially useful when welding together two adjacent plates (upper and lower) oriented vertically with a horizontal weld therebetween.
A ceramic shelf assembly in accordance with the present invention comprises one or more heat resistant ceramic blocks disposed in a line along the weldable edge of the lower plate. Blocks in a line may be joined end-to-end by a strip of heat-resistant double-sided tape to secure the line of blocks together and to the surface of the square-butt plate, with the edges of the aligned blocks disposed at the very corner of the lower plate. Preferably, when a plurality of blocks are needed, the blocks may be further connected together on their upper surfaces with a second heat-resistant tape that is wide enough to also removably attach the blocks to the metal lower plate.
Alternatively, when welding ferromagnetic materials one or both of the tapes may be omitted, and the block or blocks may be fitted with magnets disposed in recesses in the blocks for removably attaching the blocks to the lower plate.
The present invention will now be described, by way of example, with reference to the accompanying drawings, in which:
Throughout the following description, specific elements are set forth in order to provide a more thorough understanding of the invention. However, in some embodiments the invention may be practiced without some of these elements. In other instances, well known elements have not been shown or described in detail to avoid unnecessarily obscuring the disclosure. Accordingly, the specification and drawings are to be regarded as illustrative rather than restrictive. It is to be further noted that the drawings may not be to scale.
Referring now to
As shown in prior art
It is the primary object of the present invention to prevent drip 30 from occurring.
Referring to
Referring now to
While the invention has been described by reference to various specific embodiments, it should be understood that numerous changes may be made within the spirit and scope of the inventive concepts described. Accordingly, it is intended that the invention is not limited to the described embodiments but will have full scope defined by the language of the following claims.
