Patent US4770455A successfully refreshed from Google Patents.
US4770455A
Expired / Lapsed
US
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Passively activated prehensile digit for a robotic end effector
Assignee: United States, NATIONAL AERONAUTICS AND SPACE ADMIMISTRATION THE, Administrator of
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Filing: 1986-10-21
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Granted: 1988-09-13
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Expires: 2006-10-21
Abstract
Abstract A common hydraulic reservoir holds one or more rows of slidable pistons or "fingers" in a base, or "hand". The individual fingers in each row expose graduated cross-sectional fluid application areas to the hydraulic fluid in the reservoir, with the smallest fluid application area in the center of the row and graduating to progressive larger fluid areas towards both ends of each row. The fingers are elongated pistons. Exposed outer ends of each piston extending away from the reservoir, house a transverse pad to contact an object to be held. The transverse pads are universally ball-joint and spring-center mounted in a longitudinally located opening at the outer tapered end of each finger. Simple and effective capacitance metering in the reservoir is provided for each finger.
Inventors
- 👤 Earl R. Collins, Jr.
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 19:44
CPC Classifications
B; B25; B25J; B25J9/00; B25J9/10; B25J9/14; B25J15/00; B25J15/08; B25J15/10; B25J15/106; B25J17/00; B25J17/02; B25J17/0258; B25J17/0275; B25J19/00; B25J19/02; Y; Y10; Y10S; Y10S294/00; Y10S294/902
Claims Analysis
Total Claims: 22
Claim 1
Independent Claim
128 words
A workpiece holder having a plurality of pistons slidably mounted in a row of bores in a closed hydraulic reservoir system, with one end of each piston extending into and urged out of hydraulic fluid in the reservoir by pressure thereon and the other end of each piston extending outwardly away from the hydraulic reservoir to receive an object to be held, said holder comprising: a plurality of pistons each of which have individual hydraulic pressure areas in the ends thereof exposed to said hydraulic pressure and differeing in size from piston to piston; and a plurality of spring loaded workpiece contact pads, each pad universally mounted on the outer ends of said plurality of pistons and tiltable through substantial spherical angles for contact with irregular shaped objects.
Claim 2
Dependent Claim
128 words
A workpiece holder having a plurality of pistons slidably mounted in a row of bores in a closed hydraulic reservoir system, with one end of each piston extending into and urged out of hydraulic fluid in the reservoir by pressure thereon and the other end of each piston extending outwardly away from the hydraulic reservoir to receive an object to be held, said holder comprising: a plurality of pistons each of which have individual hydraulic pressure areas in the ends thereof exposed to said hydraulic pressure and differeing in size from piston to piston; and a plurality of spring loaded workpiece contact pads, each pad universally mounted on the outer ends of said plurality of pistons and tiltable through substantial spherical angles for contact with irregular shaped objects.
Claim 3
Dependent Claim
49 words
A workpiece holder as defined in claim 1 and further comprising: a graduated series of different sized pressure areas on said row of pistons with the largest hydraulic pressure areas on the outer end of said row and the smallest hydraulic pressure areas near the center of said row.
Claim 4
Dependent Claim
74 words
A workpiece holder as defined in claim 1 and further comprising: a coaxial bore in the outwardly exposed end of each piston and terminating in an outwardly facing spherical seat; a mated spherical ball formed on the underside of a contact pad and universally seated in said spherical bore; and a centering spring connected between said bore and said spherical ball for biasing said contact pad into a normally transverse position to said piston.
Claim 5
Dependent Claim
43 words
A workpiece holder as defined in claim 3 and further wherein: said centering spring is an elongated cylinder seated at one end in the center of the base of said bore and seated at the other end in the center of said ball.
Claim 6
Dependent Claim
35 words
A workpiece holder as defined in claim 1 and further wherein: said outer ends of said pistons are tapered at said universally mounted area to provide essentially 270° of spherical movement by said contact pads.
Claim 7
Dependent Claim
30 words
A workpiece holder as defined in claim 1 and further comprising: means in said reservoir for sensing the degree of movement of each of said pistons in said reservoir housing.
Claim 8
Dependent Claim
38 words
A workpiece holder as defined in claim 6 and further wherein: said movement sensing means comprises a capacitance having one capacitor plate formed on said piston end and spaced away from another capacitor plate held in said reservoir.
Claim 9
Dependent Claim
21 words
A workpiece holder as defined in claim 7 and further wherein: said capacitor relies upon said hydraulic fluid as a dielectric.
Claim 10
Dependent Claim
47 words
A workpiece holder as defined in claim 7 and further wherein: said one capacitor plate is formed by an outside circumference on the lower end of said piston and the other capacitor plate is a slightly oversized metal sleeve coaxially aligned and spaced from said lower end.
Claim 11
Dependent Claim
50 words
A workpiece holder as defined in claim 7 and further wherein: said one capacitor plate is formed by an inner surface of a longitudinal bore in the lower end of said piston and the other capacitor plate is a slightly undersized post coaxially aligned with and spaced from said bore.
Claim 12
Dependent Claim
38 words
A workpiece holder as defined in claim 7 and further wherein: said movement sensing means comprises a capacitance having one capacitor plate formed on said piston end and spaced away from another capacitor plate held in said reservoir.
Claim 13
Dependent Claim
21 words
A workpiece holder as defined in claim 11 and further wherein: said capacitor relies upon said hydraulic fluid as a dielectric.
Claim 14
Dependent Claim
85 words
A workpiece holding device having a common hydraulic fluid reservoir with a plurality of cylinder bores slidably housing a plurality of pistons extending into said reservoir and extending outwardly away therefrom, said device comprising: a plurality of pistons each of which expose graduated pressure areas to said fluid with the areas differing in size from piston to piston, and spring loaded workpiece gripping pads universally mounted on the outer ends of said pistons for exerting a graduated reaction force to an object to be held.
Claim 15
Dependent Claim
85 words
A workpiece holding device having a common hydraulic fluid reservoir with a plurality of cylinder bores slidably housing a plurality of pistons extending into said reservoir and extending outwardly away therefrom, said device comprising: a plurality of pistons each of which expose graduated pressure areas to said fluid with the areas differing in size from piston to piston, and spring loaded workpiece gripping pads universally mounted on the outer ends of said pistons for exerting a graduated reaction force to an object to be held.
Claim 16
Dependent Claim
81 words
A workpiece holder as defined in claim 13 and further comprising: a coaxial bore in the outwardly exposed end of each piston and terminating in an outwardly facing spherical seat; a mated spherical ball formed on the underside of a contact pad and universally seated in said spherical bore; and said spring loaded gripping pad further comprises a centering spring connected between said bore and said spherical ball for biasing said contact pad into a normally transverse position to said piston.
Claim 17
Dependent Claim
43 words
A workpiece holder as defined in claim 14 and further wherein: said centering spring is an elongated cylinder seated at one end in the center of the base of said bore and seated at the other end in the center of said ball.
Claim 18
Dependent Claim
35 words
A workpiece holder as defined in claim 13 and further wherein: said outer ends of said pistons are tapered at said universally mounted area to provide essentially 270° of spherical movement by said contact pads.
Claim 19
Dependent Claim
30 words
A workpiece holder as defined in claim 13 and further comprising: means in said reservoir for sensing the degree of movement of each of said pistons in said reservoir housing.
Claim 20
Dependent Claim
113 words
A workpiece holding device having a common hydraulic fluid reservoir with a plurality of cylinder bores slidably housing a plurality of pistons extending into said reservoir and extending outwardly away therefrom, said device comprising: a row of pistons each of which expose graduated pressure areas to said fluid; a graduated series of different sized pressure areas on said row of pistons with the largest hydraulic pressure areas on the outer end of said row and the smallest hydraulic pressure areas near the center of said row, and spring loaded workpiece gripping pads universally mounted on the outer ends of said pistons for exerting a graduated reaction force to an object to be held.
Claim 21
Dependent Claim
113 words
A workpiece holding device having a common hydraulic fluid reservoir with a plurality of cylinder bores slidably housing a plurality of pistons extending into said reservoir and extending outwardly away therefrom, said device comprising: a row of pistons each of which expose graduated pressure areas to said fluid; a graduated series of different sized pressure areas on said row of pistons with the largest hydraulic pressure areas on the outer end of said row and the smallest hydraulic pressure areas near the center of said row, and spring loaded workpiece gripping pads universally mounted on the outer ends of said pistons for exerting a graduated reaction force to an object to be held.
Claim 22
Dependent Claim
50 words
A workpiece holder in accordance with claim 18 wherein: the upper surface of the base forming the hydraulic reservoir is concave with the smallest area piston located in the low point of the concave surface and the largest sized area pistons located at the highest points of the concave surface.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1991-09-13 | 1992-03-14 | 1992-09-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-09-13 | 1996-03-14 | 1996-09-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-09-13 | 2000-03-14 | 2000-09-13 | $7700.00 | Window Closed / Lapsed |