This invention relates generally to composite, dismantleable spools of heavy-duty construction, adapted to carry substantial quantities and weights of metal wire. More particularly, the invention relates to spools of the above type, which are capable of low-cost fabrication and assemblage while at the same time being particularly sturdy and resistant to damage.
In the past a number of different spool constructions for holding large, heavy quantities of wire have been proposed and produced. Most prior spools consisted of a number of sheet-metal sections which were assembled to one another by welding. Generally, the cost of producing such spools was excessive, due to the relatively heavy gauge metal which was required, in addition to the cost of labor involved with the different welding procedures.
Various spool constructions of the take-apart variety have also been developed over the years. U.S. Pat. No. 2,295,222 discloses one such spool, having a central body portion and single conical end flanges releasably secured thereto. The bore of the body portion is threaded, and a corresponding threaded portion on the end flange is received therein. While this construction was considered satisfactory under certain circumstances, it can be appreciated that the costs involved with providing mating thread formations on multiple sheet-metal parts tended to be rather high, resulting in a product which was prohibitively expensive for many applications or installations.
Another prior spool construction is illustrated in U.S. Pat. No. 1,786,366. The device disclosed therein involves a pair of disk-like end flanges which are fitted to a central spool body that is constituted as an iron pipe. Annular bead formations on one side of each flange are employed for keying the flanges to the body. Multiple bolts are utilized, located off-center with respect to the axis of the spool for securing the flanges together.
While this earlier patented device operated in a generally satisfactory manner, there were still a number of disadvantages inherent in the construction. First, it was found to be quite difficult to assemble the end flanges to the spool body, since there is a tendency for the parts to shift with respect to one another as the bolts are being installed. Second, due to the small radius of curvature of the beads on the end flanges, there is encountered difficulty in effecting a proper seating thereof. Moreover, further problems are experienced in determining the proper torque to be applied to the nuts, in order to achieve a balanced or uniform pressure about the spool periphery. In addition, over-tightening of one or more of the nuts results in deformation of either or both of the end flanges, causing them to weaken and assume a somewhat concave shape. Accordingly, in the above respects the disclosed patented constructions did not prove to be satisfactory from the standpoint of either strength or low manufacturing cost.
Yet another take-apart spool is disclosed in U.S. Pat. No. 1,987,990. Here again, one of the disadvantages found is that multiple parts are involved, having unusual configurations, such as internal stop shoulders and the like, requiring special metal stampings which are costly to produce.
In my U.S. Pat. No. 4,140,289 (Ser. No. 855,279) issued on Feb. 20, 1979 and entitled "LOW-COST, DISPOSABLE, WIRE-STORAGE AND PAY-OUT SPOOL" there is disclosed a spool construction wherein conical end flanges constituted of stamped and pressed sheet metal, are assembled to a cylindrical spool body and held in place by a single drift bolt having at one end an eyelet to enable the spool to be handled by mechanical equipment. This construction of my co-pending application successfully solves most of the problems encountered in prior spool devices. However, there was required a thorough and costly surface protection of the end cones, failing which these would rust and become unserviceable particularly if subjected to moisture and/or outdoor weather conditions. If preplated or pre-finished metal stock was used prior to the formation of the end cones, the surfaces suffered abrasion and damage, resulting in a product of poor quality. Further, the storage of the end cones had to be in a dry, protected space since outdoor storage was not feasible or practical.