The Invention of the Phillips Head Screw
A 1936 patent for a cross-shaped screw head designed to keep a screwdriver centered and prevent it from slipping during high-speed assembly.
Original patent title: “Screw”
A 1936 patent for a cross-shaped screw head designed to keep a screwdriver centered and prevent it from slipping during high-speed assembly. Granted to Phillips Screw Co in 1936 with 8 forward citations, and it is now in the public domain.
Coverage
What does this patent actually cover?
The patent describes a screw with a cruciform, or cross-shaped, recess in the head. This shape allows a matching screwdriver tip to self-center, meaning the tool naturally stays in the middle of the screw head as it turns. By increasing the surface contact area between the tool and the screw, it allows for higher torque without the screwdriver slipping out of the slot. This design was specifically engineered to be used with power-driven tools on assembly lines.
The gap
What does this patent NOT cover?
- Does not cover standard flat-head or slotted screws.
- Does not cover hex-key or Allen-style internal drive systems.
- Does not cover square-drive or Robertson head screws.
- Does not cover external bolt heads that require a wrench.
These exclusions are unique to PatentBrief — derived from the actual claim language, not patent-office boilerplate.
Key facts
What made this novel
The genius lies in the tapered cross shape, which forces the screwdriver to center itself automatically, turning the act of driving a screw into a self-aligning process.
The Patent Drawing
Schematic visualization of the patent's claim structure. Hand-drawn diagrams in progress for each landmark patent.
Where you've seen this
Real-world examples
Most consumer electronics assembly
Automotive manufacturing fasteners
General household construction screws
Furniture assembly kits
Why it matters
The bigger picture
This design solved a major bottleneck in early 20th-century manufacturing. Before this, slotted screws were prone to 'cam-out,' where the screwdriver slips out of the slot, damaging the product and slowing down assembly lines. It became the industry standard for mass production, particularly in the automotive and aircraft industries.
Filed
July 3, 1934
Granted
July 7, 1936
Market context
Who's building on this
Companies in this space
The Phillips Screw Company continues to licenselicensePermission from the patent owner to make, use, or sell the invention — usually in exchange for payment. Doesn't transfer ownership.Read more → and manage the intellectual property surrounding this design. Thousands of global fastener manufacturers produce these screws daily, as the design has become a universal standard for assembly.
Market impact
This invention fundamentally enabled the modern assembly line. By reducing slippage and increasing speed, it allowed manufacturers like General Motors to assemble vehicles much faster, setting a standard that remains in place nearly a century later.
Claim 1 — Plain English
What this patent covers
The patent describes a screw with a cruciform, or cross-shaped, recess in the head. This shape allows a matching screwdriver tip to self-center, meaning the tool naturally stays in the middle of the screw head as it turns. By increasing the surface contact area between the tool and the screw, it allows for higher torque without the screwdriver slipping out of the slot. This design was specifically engineered to be used with power-driven tools on assembly lines.
The clever bit
The genius lies in the tapered cross shape, which forces the screwdriver to center itself automatically, turning the act of driving a screw into a self-aligning process.
What it does not cover
- Does not cover standard flat-head or slotted screws.
- Does not cover hex-key or Allen-style internal drive systems.
- Does not cover square-drive or Robertson head screws.
- Does not cover external bolt heads that require a wrench.
Patent timeline
Application submitted to the patent office
Application published, typically 18 months after filing
Patent officially issued
Patent enters public domain
This patent is in the public domain
See the Freedom to Build guide — what is free to use, what is not, and how to cite this patent.
PatentBrief Score
Impact Score
Limited data
Citation count
19/40
Early citations
Claim breadth
0/20
Narrow claimsclaimsThe numbered statements at the end of a patent that legally define what the inventor owns.Read more →
Recency
0/20
Older than 20 years
Assignee scale
0/20
Independent or smaller assigneeassigneeThe entity that owns the patent — usually the inventor's employer or a company.Read more →
PatentBrief Impact Score — based on citation count, claim breadth, recency, and assignee scale. Not a legal assessment.
Heuristic Value Estimate
What this patent might be worth
$5K – $15K
Midpoint $10K · expired or expiring · industry baseline
Heuristic only — blends forward/backward citation counts, claim scope, time remaining, litigation history, and CPC-derived industry baseline. Real valuations need a professional appraisal.
Claim text not yet imported for this patent
Concepts involved
Citations
Patent lineage
Cite this patent
Phillips, H. F. (1936). The Invention of the Phillips Head Screw (U.S. Patent No. 2,046,343). U.S. Patent and Trademark Office. https://patentbrief.org/patent/us/2046343/phillips-screw-screwdriver
Auto-generated from the patent record. Double-check author order and the issue date against the official USPTO document before submitting.
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Common Questions
Frequently Asked Questions
What does The Invention of the Phillips Head Screw cover?
A 1936 patent for a cross-shaped screw head designed to keep a screwdriver centered and prevent it from slipping during high-speed assembly.
Who owns patent US 2046343?
Phillips Screw Co owns this patent, granted in 1936.
When does this patent expire?
This patent has expired and is now in the public domain — anyone can use the invention freely.
What is patent US 2046343 cited by?
This patent has been cited by 8 later patents that build on its ideas.
What problem does this patent solve?
This design solved a major bottleneck in early 20th-century manufacturing. Before this, slotted screws were prone to 'cam-out,' where the screwdriver slips out of the slot, damaging the product and slowing down assembly lines. It became the industry standard for mass production, particularly in the automotive and aircraft industries.
What does this patent NOT cover?
Does not cover standard flat-head or slotted screws.
Patent monitoring