Invalidity dossier
US 5778989
Screw driving tool
Current assignee: Hilti AG
Added 9/21/2026, 10:46:05 AM
Active provider: DeepSeek · deepseek-flash
Patent summary
Title, assignee, inventors, filing/issue dates, abstract, and a plain-language overview of the claims.
Patent Overview — US 5,778,989 A
Title: Screw driving tool
Assignee: Hilti AG (original and current assignee per the listing)
Inventor: Anton Neumaier
Priority date: 1995-07-26 · Filed: 1996-07-26 · Granted/Published: 1998-07-14 · Application no.: US 08/687,873
Status: Expired – Lifetime (anticipated expiration 2016-07-26)
Classification: B25B 23/00, B25B 23/0064 (screwing-depth adjustment), B25B 23/14, B25B 23/141 (mechanical overload release couplings)
Source: https://patents.google.com/patent/US5778989/en
Purpose. The tool is a manually operable, motor-driven screwdriver, particularly for installing surface-flush or countersunk screws. Its stated object is a clutch that is economical to manufacture and features low weight and low wear — addressing drawbacks of the prior-art clutch disclosed in EU-PS 0 195 853, whose large teeth and heavy parts raised tool weight and wear.
Plain-language scope. The housing holds a motor, a motor-driven drive pinion fixed axially in the housing, and a spindle that is axially displaceable against a spring. A clutch element sits between pinion and spindle: per the description, a ball that is radially displaceable in a passageway through the drive pinion extending transversely to the driving direction. An actuation member moves the ball; when engaged, the ball cooperates with at least a stop face on the spindle (described as an axially extending groove) to rotationally lock spindle and pinion. Stops on the spindle displace the actuation member axially. Further described features: a detent element (ball) affixing the actuation member axially to the drive pinion; a retaining element cooperating with the spindle; a spring whose force does not exceed that of the spring acting on the drive pinion; and an unlatching member (O-ring) on the spindle that releases the detent so the clutch disengages automatically when the depth stop contacts the material. Figures 1–4 show the tool and clutch fully disengaged, fully engaged, and just before disengagement.
What the excerpt does not establish. It does not state claim language or claim count, does not identify issued claims versus description, lists no cited prior-art references beyond EU-PS 0 195 853, and does not address validity, enforceability, or ownership changes. The classification and legal-status fields are expressly noted in the source as assumptions, not legal conclusions.
Generated 10/1/2026, 10:01:10 PM
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Litigation summary
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PTAB challenges
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Assignment history
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Prior art
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Obviousness
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Extensions
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Derivative works
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