Patent 1491
Patent Summary
An image of the technical drawings for patent number 1491.
Name/Title
Patent 1491Entry/Object ID
2025.3.3Tags
1800s, newton, roome, patent summary, shears, scissorsDescription
1491. Newton, W.E., [Roome, J.H.] June 21. Scissors and shears. Tailors’ shears have their parts so combined that the leverage exerted by the hand in cutting is gradually increased as the shears close. Figs. 1 and 2 show opposite sides of a pair of shears, in which the handle B and blade A of one limb are made in one piece. The other limb is composed of two pieces – the part C, D, turning about the pin a and consisting of the blade C and the arm D which is connected to the second piece E, G, f, capable of turning about the pin g and comprising the handle E, G, and the arm f. The blade C has a slot b having the form of an arc described from the pin a; this slot b receives the screw c from the lower blade A. The arm D also has a slot d, receiving a pin e carried by the arm f. The pin g is fitted with antifriction rollers and moves in a slot in the handle E, thus allowing the handle to have a longitudinal as well as a lever-like movement. The front end of the handle E, G is connected with the part C, D by a link F, the pin J being so arranged that it is a little in rear of and some distance beneath the pin a. The arm f is made of forked form to receive the arm D, and carries a roller on the pin l. The spring H is secured to the lower limb A, B, and assists in opening the shears after a cut has been made. On depressing the handle E, the front end of the lever E, G rises, and the arm f moves backwards, causing the aforementioned roller to pass along the lower edge of the arm D and so depress the blade C. At the same time the end of the link F is forced bodily backwards by the movement of the part C, D, and so forces the lever E, G back on its fulcrum f, thus gradually increasing the length of lever behind the pin and so increasing its power as the blade C descends. Also, the roller, in gradually receding from the fulcrum a, causes the power applied by the lever to act with increased effect on the blade. To allow for wear, the arm f is made detachable from the lever E, G, and is secured thereto by a screw m passing through a slot n in the arm f and screwing into the lever E, G. (For Figures see next page.)Category
Patent Summaries