nettlefold’s lock.

671

and spring made out of one and the same piece ofmetal. This lock, when fixed on a pianoforte, isperfectly free from any noise or jar incidental tosome other locks caused by the vibration of theirseveral parts.

The claims set forth in the specification are—First,—The moving the bolt by means of a diagonalslot, or two inclined planes in a sliding-plate actingupon a stud or studs in the bolt.

Secondly.—The application to locks of an oscil-lating-tumbler for moving the bolt.

Thirdly. — The forming the levers and theirsprings in one and the same piece of metal.

Fourthly.—The application to locks of an ex-panding-stump.

Fifthly.— The application to the bolts of locks ofa hanging-plate, carrying a stump, and also a studwhich enters an inclined notch in the bolt, so thatwhen end pressure is applied to the bolt, theinclined face of the notch acting upon the studthrows up the hanging-plate, and prevents thestump from entering the notch in the lever.

Sixthly.—The application to locks of two discscarrying two stumps acting upon the bolt, so asto prevent the stump on one of the discs fromentering the notch in the lever when end pressureis applied to the bolt.

Seventhly.—-The application of a sliding-shieldoperating to prevent access to the levers by meansof false keys.