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Signed Engineering Document by Lewis H. Latimer – Elevator Safety Mechanism

Letter
This is a typed engineering document detailing an elevator safety mechanism and lifting device, signed by inventor Lewis H. Latimer at the bottom in flowing cursive script with the title "Inventor" beneath his name. The document outlines three distinct devices related to suspended elevators and lifting mechanisms: A suspended elevator raised and lowered by cables, featuring a safety device with vertically arranged screw bars to prevent free-falling if the cables break. A single motor device that operates screw nuts for safety purposes or independent elevation control. A lifting device utilizing a motor and screw system to raise and lower the elevator. It also discusses broader applications of the lifting mechanism beyond elevators, such as in screw jacks and reciprocating machines. In the lower-left corner, there is a small hand-drawn sketch labeled "Screw Coupling," likely illustrating part of the described mechanism.
Signed Engineering Document by Lewis H. Latimer – Elevator Safety Mechanism picture number 1

Lewis H. Latimer (1848–1928) was an African American inventor and engineer known for his significant contributions to electric lighting, patent drafting, and mechanical engineering. While he is most famous for his work with incandescent light bulbs and electric lamp patents, he also contributed to mechanical engineering innovations such as this elevator safety mechanism. The mention of reciprocating motion and screw jacks suggests this design had potential applications in industrial lifting equipment and transportation machinery. This document serves as a rare example of Latimer’s mechanical innovations outside of electric lighting, showcasing his versatile engineering expertise.

The Lewis H. Latimer Papers (1870-1929, 1972) [QPL Subgroup]Latimer Family Papers (1870-1996 ) [QPL Full Collection]

Main Text: "In this drawing are shown three distinct devices. 1st. A suspended elevator, raised and lowered by the suspending cables, and provided with safety devices consisting of two or more vertically arranged screw bars, with which motors placed upon the car are in engagement, for the purpose of preventing the falling of the car in the event of the breaking of the suspending cable. The above for raising and lowering the car independently of the suspending cables. 2nd. A single motor arranged upon the cargo as to operate screw nuts A, Fig. 3, in the manner above stated, as a safety device or for raising and lowering the car. 3rd. A lifting device, consisting of a motor and screw arrangement, as shown in Fig. 2, for the purpose of raising and lowering the car. "The principle shown in Fig. 2 (unless some unforeseen defect should develop in practice) has a wide application. It can, for instance, be used for screw jacks, and on some kinds of machines where a steady reciprocating motion is required." Sketch Label: "Screw Coupling." Signature: "L. H. Latimer Inventor