Peer’s Patent Model of Gear Cutting Machine, 1874
date: label: date made
content: 1874
label: patent date
content: 1874-07-21
name: label: inventor
content: Peer, John A.
notes: label: Description
content: This model was filed with the application to the U.S. Patent Office for Patent Number 153,370 issued to John A. Peer of San Francisco, California on July 21, 1874. The patent was for an improvement in gear cutting machines.
label: Description
content: Mr. Peer’s design was for a complex cutting machine that could be set up to construct a variety of different types of gears. The patent claimed that, with only simple adjustments, the machine could cut bevel, spur, crown, mortise, face, spiral and rack-bar gears. The machine was capable of cutting gears in metal and wood, and its design assured the teeth of the gears would be perfectly symmetrical.
label: Description
content: As seen in the image of the patent model, the machine consisted of a lathe-bed with a head-block (at the far left of the image) holding a pulley-driven spindle into which the blank to be cut was chucked. The spindle had a control plate mounted at the outer edge. The plate was drilled with holes arranged at appropriate angles for each type of gear to be cut and was indexed into position by a lever and pin.
label: Description
content: The cutting blades were mounted in the center of a set of adjustable frames that allowed them to engage the blank at the appropriate horizontal and vertical position. Screw jacks moved the frames into position for each series of cuts. An inner frame (the angled brass frame in the image) could be set for the proper angle for bevel gears, and the cutters could also be moved along that frame to effect the cuts. Mr. Peer made provisions for cutting rack gears by replacing the spindle and chuck with a horizontal rack bed.
label: Description
content: This patent model was on display in the Oval Office of the White House from 2009 to 2017.
label: Description
content: The patent model is made of brass, steel and wood. All of the key elements of the patent are illustrated by the model. Diagrams showing the complete design can be found in the patent document online (www.USPTO.gov).
label: Location
content: Currently not on view
place: label: associated place
content: United States: California, San Francisco
topic: label: Subject
content: Patent Models
setName: label: See more items in
content: Work and Industry: Production and Manufacturing
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content: Engineering, Building, and Architecture
label: See more items in
content: Patent Models
dataSource: label: Data Source
content: National Museum of American History
identifier: label: ID Number
content: MC.308817
label: catalog number
content: 308817
label: accession number
content: 89797
label: patent number
content: 153,370
objectType: label: Object Name
content: patent model, gear cutting machine