The essence of the Hoff patent consists in his method of manufacture, by taking a blank sheet of metal of the proper size and shape, folding it in the for of a cone, and then crimping the smaller end to form the bottom, which is thus made much thicker and more durable than the sides. The bottom shown in his drawings is composed of a series of concentric rings, but he states in his specifications that he does not desire to limit himself to any particular form of crimp or fold for the bottom of the hod, since it is evident that the form of the fold may be changed and still have the tapering end of the blank compressed to force the surplus metal to fold over and strengthen the bottom, and it is also evident that the blank may be varied to suit different shapes of hods.
To ascertain the exact scope of this patent it is necessary to examine the state of the art at the time it was issued. The crimping or doubling in of the ends of paper packages has, of course, been a common practice from time immemorial. The patent to George Smith, No. 124,093, issued February 27, 1872, exhibits a coal-hod in the shape of an inverted hollow cone, the apex of the cone being the bottom and center of the hod. It differs from any ordinary coal-hod only in dispensing with the ordinary horizontal bottom, and contains no suggestion of the crimping process, which is the main feature of the Hoff patent hod, although a method is suggested of repairing the bottom of the hod by the substitution of a new cone, which constitutes the chief feature of the invention.
The patent to Edward F. O'Toole, May 22, 1877, No. 191,071, exhibits a coal-hod formed of a blank piece of metal, forced into a series of vertical crimps upon both sides of the hold. The crimps begin at the bottom of the hod, and widen towards the top. The bottom, however, is rectangular, and composed of a single sheet of metal, so that the hold is really the weakest at the part which is subjected to the greatest wear.
Patent No. 199,370, of January 22, 1878, to Isaac F. Kearns, relates to a method of strengthening or re-enforcing those parts of tin vessels most subject to wear and strain, in forming upon the bottom of the vessel a fold, which is bent up against the bottom until it is flat, so that at the fold there are three thicknesses of metal in close contact to resist wear at this exposed point. After being thus provided with the flattened fold the vessel is retinned, so that the crevices on the inside and outside are closed, and water excluded from the fold. This, though evidently for a bottom-forming process, contains but a faint suggestion of the patent in suit,-both the process of manufacture and the result being entirely different from those shown in plaintiff's patent.
The patent to Clark and Wells, No. 221,522, of November 11, 1879, for an improvement in metallic baskets, exhibits a body made of a rectangular blank or piece of sheet metal, which is bent in cylindrical form, with the ends of the sheet metal overlapping each other and riveted, while the metal is straight. The corrugations are made broad and shallow at their upperends, near the top of the backet, and then gradually decrease in width and increase in depth towards the bottom. It is somewhat similar in principle to the O'Toole patent, and, like that, differs from the plaintiff's in failing to provide for an increased thickness for the bottom, which is an ordinary one and secured to the body by the usual seaming process.