Thomson-Houston Electric Co. v. H. W. Johns Manuf'g Co.

The complainant may take injunction restraining the making or sale of any trolley frog or switch devised oí* intended to be used in infringement of such claims of the patent sued upon as were sustained by the court of appeals. It is not intended, however, to enjoin against the sale of trolley frogs or switches by way of replacement of broken frogs or switches, or such as are worn out by use, or of substitution for trolley frogs or switches previously sold by the owner of the patent to purchasers from it. Defendants, however, must determine, at their peril, whether the purchaser buys to use for infringement, or only for legitimate repair; but this permission to repair does not give authority to reconstruct or rebuild a combination which has been sold by the owner of 'the patent. Injunction may run against the officers as well as the corporation defendant. Possibly, under the stimulus of an apprehended prosecution for contempt, they may familiarize themselves with the kind of goods their company is publicly advertising for sale, and thus infringement may be more satisfactorily checked than it would otherwise be.