Walter Schlage: Inventor of the Bored Cylindrical Lock

Early Life and Work

Schlage was born in 1882 in Thuringia, Germany. A 1946 obituary in the San Mateo Times gives that birth year and says he took a position with the Western Electric Company in San Francisco in 1905. Locksmith Ledger's 2004 history of the company gives the same 1905 start at Western Electric. Two company histories (Gale's International Directory of Company Histories, reproduced on Encyclopedia.com, and Wikipedia) say he trained at the Carl Zeiss optical works in Jena and worked briefly as an instrument maker in London before emigrating. Those training details are not in the patent record.

His first patent shows where his interests started. U.S. Patent 921,168, "Combined Lock and Signal and Lighting Switch," was filed December 14, 1908 and granted May 11, 1909. In it Schlage describes himself as "a citizen of Germany, residing at Berkeley." The invention ties an electric circuit for lights or signals to the action of a door lock.

The Path to the Cylindrical Lock

Between that first patent and the founding of his company, Schlage kept working on knob-operated locking. U.S. Patent 1,313,920, "Door Lock," was filed March 29, 1917 and granted August 26, 1919. By then he described himself as a United States citizen living in Berkeley. The stated aim was "a simple, substantial, cheaply manufactured, easily applied locking mechanism operated by the door knob." Its objects include locking the knob, spindle, and hub against turning, holding the latch against being pushed back "by a jimmy," and showing visibly whether the door is locked.

The key patent came next. U.S. Patent 1,456,041, "Door Lock," was filed April 12, 1920 and granted May 22, 1923. Schlage assigned it to Schlage Manufacturing Company of San Francisco. The patent describes:

• A lock housing that is "cylindrical in cross section" and holds the entire lock mechanism as one unit.
• A housing secured to the door "from one side only."
• Installation by drilling a hole through the door so the cylindrical casing fits "snugly therein."
• A design that can be installed "without cutting away an excess of the wood work or otherwise weakening the door structure."

That is the bored-lock idea in Schlage's own words: one round hole through the face of the door and a self-contained unit, in place of a large mortise pocket cut into the door edge. For how the format works today, see cylindrical locks and, for the older approach, mortise locks.

The Push-Button Lock

A second patent filed the same year added the feature most people associate with the Schlage name. U.S. Patent 1,489,675, "Door lock," was filed October 5, 1920 and granted April 8, 1924, also assigned to Schlage Manufacturing Company. It describes itself as an improvement on his 1919 patent. The lock is set by pressing a push button in the inside knob and released by turning that knob, and it is designed to show whether the door is locked.

Allegion, the company that owns Schlage today, says in its 2018 annual report that Schlage "was awarded the first patents granted for the cylindrical lock and the push button lock." That is the company's own claim. This article reports the patents and their dates rather than ruling on "first."

Keyed Designs

Schlage's early locks were not key-operated. Later patents show the move to keyed cylinders:

• U.S. Patent 1,653,511 (filed May 9, 1923; granted December 20, 1927) covers a key-actuated lock using "a rocking type of tumbler."
• U.S. Patent 1,691,529 (filed January 24, 1927; granted November 13, 1928) covers a key-actuated tumbler lock in which "all parts may be constructed from stamped metal." The patent classification places it among locks with plate tumblers that are set by pushing the key in. Locksmith Ledger describes this as Schlage's seven-tumbler wafer lock.

The emphasis on stamped sheet-metal parts runs through these patents, and it matches the goal of a lock that was cheap to make and quick to install. For the tumbler types, see wafer locks and pin tumbler locks.

The Company

Locksmith Ledger reports that the State of California issued a certificate of incorporation to Schlage Manufacturing Company in 1920. Gale's company history reports that the company, by then known as Schlage Lock Company, was in financial difficulty by 1926. It says San Francisco businessman Charles H. Kendrick invested and became president in 1927, beginning a long partnership with Schlage.

Schlage died in 1946. Gale's history and the San Mateo Times obituary both give that year.

Later ownership is documented in company and securities filings:

• 1974: Ingersoll-Rand acquired Schlage Lock Company. Allegion's 2018 annual report describes its entry into the security business as "the acquisition of Schlage, Von Duprin and LCN in 1974."
• 2013: Ingersoll Rand spun off its commercial and residential security businesses as Allegion. Allegion became a standalone public company on December 1, 2013 and began trading on the New York Stock Exchange under the symbol ALLE.

Legacy

BHMA standards treat bored locks as their own product category. ANSI/BHMA A156.2-2022 covers bored and preassembled locks; its Grade 1 operational test is 1,000,000 cycles. See ANSI/BHMA lock grades and cylindrical locks.

Schlage sits alongside Harry Soref, Linus Yale Sr. and Jr., and James Sargent among inventors whose names became American lock brands.

Related Topics

• Cylindrical locks: the format his 1920 patent describes
• Mortise locks: the format bored locks were designed to avoid
• Lock functions: privacy, passage, entrance and more
• ANSI/BHMA lock grades: how bored locks are graded
• Wafer locks: the plate-tumbler type in his 1927 patent
• Notable figures: other inventors
• Yale & Towne: another inventor-founded lock company

Sources