Measures to secure a patent for the above have been taken by George B. Read, of New York City. All mechanics have had too much practical experience of the difficulty of keeping adjustable wrenches properly fixed, so that they may not slip around the nut instead of firmly grasping it. The inventor has hit upon a happy device to attain this desideratum by the following plan. One jaw which | is attached to the wrench stock by a pivot has | a recess through it, in which slides the shank ; of the other jaw, which is therefore adjusta- ; ble, and its shank is provided with a rack into ' which catches a pawl attached to the stock and held in position, by a spring. By this construction, as the handle ot the wrench is turned, the two jaws are forced against the sides of the nut, more especially grasping the outer corners of it, the failure to do which is the cause of the slipping so common in other wrenches.
This article was originally published with the title "Improved Wrench" in Scientific American 8, 18, 140 (January 1853)