Dinuba Steel Products Corp. v. Killefer Mfg. Corp.

Plaintiff, as the assignee of patent No. 1,584,644, issued to Hugo Petzoldt of date May 11, 1926, sued defendant for an injunction against infringement and for an accounting. The defense is that Petzoldt was not the first inventor of the thing patented, claim of invalidity, and denial of infringement.

The patent is for a power lift device for heavy earth-working tools, such as subsoil plows, cultivators, road levelers, and road-building machinery. Such devices are old in the art, and all of the elements are ancient. The claims are therefore narrow.

Petzoldt conceived the idea of a combination for a power lift device which operated with an automatic kick-off. This feature is simple and novel, and, as the file wrapper shows, was the inducing cause for the issuance of the patent.

Claim 1, which it is averred is infringed, reads as follows: “In a power lift implement, a frame, an axle journaled transversely of said frame, an arm on each end of the axle, each arm terminating at the lower end with a spindle, traction wheels rotatable on said spindle, a pair of spaced discs mounted on one spindle and fixed to the adjacent wheel, a plurality of pins extending transversely between the…