Patent US5001808A successfully refreshed from Google Patents.
US5001808A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Shielded castor with spring
Assignee: Individual
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Filing: 1990-03-29
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Granted: 1991-03-26
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Expires: 2010-03-29
Abstract
Abstract A castor, which can efficiently absorb shock and the ball wheel of which can be alternatively received in or protruding beyond a cup-like shield thereof for positioning or moving. The caster comprises a sleeve which is secured to a hoop on the frame of a baby-walker for receiving a spring and a central shaft which comprises a ball wheel on the bottom. The sleeve comprises a Z-shaped track on its wall surface for the sliding and positioning therein of a lateral guide which is inserted therethrough and secured to the central shaft. A cup-like shield is secured to the bottom end of the sleeve to protect the ball wheel.
Inventors
- 👤 Chin-Fu Chung
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 19:01
CPC Classifications
B; B60; B60B; B60B33/00; B60B33/04; B60B33/06; B60B33/0036; B60B33/0039; B60B33/006; B60B33/0063; B60B33/02; B60B33/021; B60B33/023; B60B33/08; B60B2200/00; B60B2200/40; B60B33/0002; B60B33/0015; B60B33/0023; B60B33/0047; B60B33/0049; B60B33/0055; B60B33/0065; B60B33/0068; B60B33/0073; B60B33/0078; B60B33/0092
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
141 words
A castor, including a sleeve secured to a circular hoop on the frame of a baby-walker by means of screws, having a Z-shaped track on its wall surface and an inner flange on its bottom end; a cup-like shield secured to the bottom end of said sleeve; a central shaft comprising a collar on its upper end and being movably fastened in said sleeve with its collar stopped against said inner flange; a lateral guide inserted through said Z-shaped track and secured to said central shaft permitting its one end to protrude beyond said sleeve; a spring received in said sleeve with its one end stopped against the bottom surface of said circular hoop and its other end stopped against said collar; and a ball wheel secured to the bottom end of said central shaft by means of an universal knuckle.
Claim 2
Dependent Claim
141 words
A castor, including a sleeve secured to a circular hoop on the frame of a baby-walker by means of screws, having a Z-shaped track on its wall surface and an inner flange on its bottom end; a cup-like shield secured to the bottom end of said sleeve; a central shaft comprising a collar on its upper end and being movably fastened in said sleeve with its collar stopped against said inner flange; a lateral guide inserted through said Z-shaped track and secured to said central shaft permitting its one end to protrude beyond said sleeve; a spring received in said sleeve with its one end stopped against the bottom surface of said circular hoop and its other end stopped against said collar; and a ball wheel secured to the bottom end of said central shaft by means of an universal knuckle.
Claim 3
Dependent Claim
45 words
A castor according to claim 1, wherein said Z-shaped track includes an upper, leftward branch track and a lower, rightward branch track so that said ball wheel can be controlled by said lateral slide to constantly be received in said cup-like shield or protrude therebeyond.
Claim 4
Dependent Claim
32 words
A castor according to claim 1, wherein said upper, leftward branch track and said lower, rightward branch track each comprises a circular hole at an inner side for retaining said lateral guide.
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) | 1994-03-25 | 1994-09-24 | 1995-03-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1998-03-25 | 1998-09-24 | 1999-03-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2002-03-25 | 2002-09-24 | 2003-03-26 | $7700.00 | Window Closed / Lapsed |