US3866519A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Piston of piston type fluid pump motor
Assignee: Aisin Corp
•
Filing: 1973-01-16
•
Granted: 1975-02-18
•
Expires: 1993-01-16
Abstract
Abstract A piston used in a piston type fluid pump motor comprises a plurality of piston heads which are each rotatably mounted on a single rod by ball-and-socket joints. Reduced friction between the piston heads and a cylinder wall avoids seizure of the piston and cylinder wall during operation.
Inventors
- 👤 Takayaki Miyao
- 👤 Hiroaki Maeda
- 👤 Masanori Sato
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 16:29
CPC Classifications
F; F01; F01B; F01B3/00; F01B3/0082; F01B3/0085
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
66 words
A piston used in a piston type fluid pump motor which comprises at least two piston heads fitted in a cylinder barrel having coaxially aligned portions, each of said piston heads being rotatably jointed by a ball-and-socket joint to a rod which is movably connected to a swash plate, whereby a torque generated on said swash plate is transmitted to said cylinder through said piston heads.
Claim 2
Dependent Claim
66 words
A piston used in a piston type fluid pump motor which comprises at least two piston heads fitted in a cylinder barrel having coaxially aligned portions, each of said piston heads being rotatably jointed by a ball-and-socket joint to a rod which is movably connected to a swash plate, whereby a torque generated on said swash plate is transmitted to said cylinder through said piston heads.
Claim 3
Dependent Claim
44 words
A piston according to claim 1, wherein each of said piston heads comprises: a housing of a substantially cylindrical shape rotatably jointed by said ball-and-socket joint formed with a convex spherical surface on said rod and a concave spherical surface on said piston head.
Claim 4
Dependent Claim
27 words
A piston according to claim 1, wherein the other end portion of said rod is connected to a shoe which is slidably fitted onto a swash plate.
Claim 5
Dependent Claim
30 words
A piston according to claim 1, wherein a shoe is fitted to one end of said rod and slidably fitted to a swash plate whereby said rod can move reciprocally.
Claim 6
Dependent Claim
24 words
A piston according to claim 1, wherein a bush is mounted in said piston head to joint with said rod by said ball-and-socket joint.
Claim 7
Dependent Claim
19 words
A piston according to claim 1, wherein said piston is used in an axial piston type fluid pump motor.
Claim 8
Dependent Claim
28 words
A piston according to claim 1, which further comprises a lubricant recess on each of said piston heads which is connected to a lubricant passage in a rod.
Claim 9
Dependent Claim
19 words
A piston as set forth in claim 1, wherein said rod has a middle portion and two end portions.
Claim 10
Dependent Claim
37 words
A piston according to claim 1, wherein one of said piston heads is jointed at the middle portion of the rod and a second of said piston heads is jointed to one end portion of said rod.
Claim 11
Dependent Claim
35 words
A piston as set forth in claim 9, further comprising: drive means for applying a torque to said piston heads; and means for providing a reaction force to the other end portion of said rod.
Claim 12
Dependent Claim
54 words
A piston according to claim 1, wherein one of said piston heads is fitted to one part of a cylinder barrel connected to a valve and rotatably jointed to a rotary shaft, and the other of said piston heads is fitted to a separate part of said cylinder barrel mounted to said rotary shaft.
Claim 13
Dependent Claim
28 words
A piston as set forth in claim 10, wherein said means for providing a reaction force to the other end portion of said rod is a swash plate.
Claim 14
Dependent Claim
39 words
A piston according to claim 11, wherein a rotary center of said first piston head corresponds to a centroid of said piston and a rotary center of said second piston head corresponds to a centroid of a piston-shoe system.
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) | 1978-02-17 | 1978-08-19 | 1979-02-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-02-17 | 1982-08-19 | 1983-02-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-02-17 | 1986-08-19 | 1987-02-18 | $7700.00 | Window Closed / Lapsed |