Patent US3175641A successfully refreshed from Google Patents.
US3175641A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Mobile ladders
Assignee: Enviri Corp
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Filing: 1963-06-19
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Granted: 1965-03-30
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Expires: 1983-06-19
Abstract
No abstract record available.
Inventors
- 👤 Robert J Mihalik
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 22:40
CPC Classifications
E; E06; E06C; E06C1/00; E06C1/02; E06C1/38; E06C1/397; E06C5/00; E06C5/32
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
200 words
IN A MOBILE LADDER ASSEMBLY EMBODYING A FRAME HAVING SPACED FIXED LEGS, A LADDER HAVING A LOWER STEP OF WHICH ONE EDGE IS PIVOTED AND THE OPPOSITE EDGE IS SPRING CUSHIONED ON SAID FRAME, A CASTER MOUNTED ON SAID FRAME AT A LEVEL BELOW SAID STEP AND HAVING A VERTICALLY SLIDABLE STEM SPRING BIASED TOWARD UP POSITION, AND A BELL CRANK PIVOTED ON THE FRAME AND COMPRISING A LONG ARM AND A SHORT ARM OPERATIVELY ASSOCIATED WITH SAID STEM, THE COMBINATION INCLUDING A CAM EXTENDING DOWNWARDLY FROM SAID STEP, A ROCKER LINK PIVOTED ECCENTRICALLY ON THE FRAME IN POSITION TO BE ROCKED BY SAID CAM WHEN DOWNWARD PRESSURE IS APPLIED TO SAID STEP, A SECOND LINK PIVOTALLY CONNECTING SAID ROCKER LINK WITH A MIDPORTION OF SAID LONG ARM, A TOGGLE ROD PIVOTED AT ONE END TO SAID ROCKER LINK, A COMPRESSION SPRING OPERATIVELY MOUNTED ON SAID ROD BETWEEN THE PIVOTAL CONNECTION THEREOF WITH SAID ROCKER LINK AND A PORTION OF A FRAME AND ARRANGED AND ADAPTED TO BIAS THE ROCKER LINK TOWARD ONE ANGULAR POSITION WHEN THE CASTER IS IN RAISED POSITION AN TO BIAS THE ROCKER LINK TOWARD A DIFFERENT ANGULAR POSITION WHEN THE CASTER IN IN DOWN POSITION.
Claim 2
Dependent Claim
200 words
IN A MOBILE LADDER ASSEMBLY EMBODYING A FRAME HAVING SPACED FIXED LEGS, A LADDER HAVING A LOWER STEP OF WHICH ONE EDGE IS PIVOTED AND THE OPPOSITE EDGE IS SPRING CUSHIONED ON SAID FRAME, A CASTER MOUNTED ON SAID FRAME AT A LEVEL BELOW SAID STEP AND HAVING A VERTICALLY SLIDABLE STEM SPRING BIASED TOWARD UP POSITION, AND A BELL CRANK PIVOTED ON THE FRAME AND COMPRISING A LONG ARM AND A SHORT ARM OPERATIVELY ASSOCIATED WITH SAID STEM, THE COMBINATION INCLUDING A CAM EXTENDING DOWNWARDLY FROM SAID STEP, A ROCKER LINK PIVOTED ECCENTRICALLY ON THE FRAME IN POSITION TO BE ROCKED BY SAID CAM WHEN DOWNWARD PRESSURE IS APPLIED TO SAID STEP, A SECOND LINK PIVOTALLY CONNECTING SAID ROCKER LINK WITH A MIDPORTION OF SAID LONG ARM, A TOGGLE ROD PIVOTED AT ONE END TO SAID ROCKER LINK, A COMPRESSION SPRING OPERATIVELY MOUNTED ON SAID ROD BETWEEN THE PIVOTAL CONNECTION THEREOF WITH SAID ROCKER LINK AND A PORTION OF A FRAME AND ARRANGED AND ADAPTED TO BIAS THE ROCKER LINK TOWARD ONE ANGULAR POSITION WHEN THE CASTER IS IN RAISED POSITION AN TO BIAS THE ROCKER LINK TOWARD A DIFFERENT ANGULAR POSITION WHEN THE CASTER IN IN DOWN POSITION.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1968-03-29 | 1968-09-28 | 1969-03-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1972-03-29 | 1972-09-28 | 1973-03-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1976-03-29 | 1976-09-28 | 1977-03-30 | $7700.00 | Window Closed / Lapsed |