US3648294A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Endoprostheses, especially for hip joints
Assignee: Individual
•
Filing: 1970-02-04
•
Granted: 1972-03-14
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Expires: 1990-02-04
Abstract
Abstract Disclosed are endoprostheses which include a piston forming a joint head and mounted on a bone and a cylinder for receiving the piston and mounted in the mating bone. The cylinder is divided into two sections, the section for receiving the piston contains a liquid, advantageously in bellows, which liquid is forced into the other section of the cylinder to compress a gas, the compressed gas therein thereby cushioning shocks. Flow of liquid between the sections is controlled by back pressure valves.
Inventors
- 👤 Esfandiar Shahrestani
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 03:40
CPC Classifications
A; A61; A61F; A61F2/00; A61F2/02; A61F2/30; A61F2/32; A61F2/30721; A61F2/30742; A61F2002/30001; A61F2002/30316; A61F2002/30535; A61F2002/30563; A61F2002/30581
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
126 words
In endoprosthesis including an articial head joint adapted to be fastened to a preselected bone and having first and second portions axially movable relative to each other and a jointsocket receiving said head, the improvement comprising: means for absorbing impact disposed between said first and second portions, said impact absorbing means comprising a piston including a piston rod extending therefrom adapted to mount said piston to said preselected bone; a cylinder having one portion defining a chamber for closely receiving said piston and another portion forming a dome; and, a partition separating said chamber and said dome from each other, said partition including means transmitting a cushioning liquid therethrough between said chamber and said dome in response to axial movement of said piston within said chamber.
Claim 2
Dependent Claim
126 words
In endoprosthesis including an articial head joint adapted to be fastened to a preselected bone and having first and second portions axially movable relative to each other and a jointsocket receiving said head, the improvement comprising: means for absorbing impact disposed between said first and second portions, said impact absorbing means comprising a piston including a piston rod extending therefrom adapted to mount said piston to said preselected bone; a cylinder having one portion defining a chamber for closely receiving said piston and another portion forming a dome; and, a partition separating said chamber and said dome from each other, said partition including means transmitting a cushioning liquid therethrough between said chamber and said dome in response to axial movement of said piston within said chamber.
Claim 3
Dependent Claim
77 words
In endoprosthesis described in claim 1, wherein said transmitting means comprises intake and outlet channels in said partition, said liquid filling at least said chamber such that axial movement of said piston in said chamber toward said partition forces said liquid into said dome through said intake channels, said dome including means for forcing said liquid back into said chamber through said outlet channels as said piston is moved axially away from said partition in said chamber.
Claim 4
Dependent Claim
32 words
In endoprosthesis described in claim 2, said forcing means comprising a closed and compressible bladder in the interior of said dome which bladder is acted upon by the liquid entering said dome.
Claim 5
Dependent Claim
21 words
In endoprosthesis described in claim 3, further including back-pressure valves opening and closing said intake and outlet channels in said partition.
Claim 6
Dependent Claim
24 words
In endoprosthesis described in claim 2, further including at least one constantly open pressure-balance channel in said partition interconnecting said chamber with said dome.
Claim 7
Dependent Claim
20 words
In endoprosthesis described in claim 4, wherein said valves are elastic valve plates for closing said intake and outlet channels.
Claim 8
Dependent Claim
20 words
In endoprosthesis described in claim 4, wherein said valves are spring-loaded valve plates for closing said intake and outlet channels.
Claim 9
Dependent Claim
26 words
In endoprosthesis described in claim 5, wherein the total cross section of said intake channels is substantially larger than the cross section of said pressure-balance channels.
Claim 10
Dependent Claim
31 words
In endoprosthesis described in claim 2, further including a compressible pleated bag disposed in said chamber adjacent said partition containing said liquid in said chamber, said piston acting against said bag.
Claim 11
Dependent Claim
53 words
In endoprosthesis described in claim 9, further including a plastic sealing cuff disposed adjacent the end of said cylinder embracing said piston for enclosing and sealing said piston rod; and, a ring plate surrounding said cuff adapted to clamp the free edge of said cuff to the upper boundary of said preselected bone.
Claim 12
Dependent Claim
28 words
In endoprosthesis described in claim 10, wherein said cylinder is made of stainless steel and is coated with a wear-resistant synthetic material which is connected with said cuff.
Claim 13
Dependent Claim
30 words
In endoprosthesis described in claim 11, said joint socket for receiving said head is formed of a wear-resistant synthetic material and is adapted to be fastened to a pelvic bone.
References Cited (Backward Citations)
FR1222634A
Cited
US3064645A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1975-03-14 | 1975-09-13 | 1976-03-14 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-03-14 | 1979-09-13 | 1980-03-14 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-03-14 | 1983-09-13 | 1984-03-14 | $7700.00 | Window Closed / Lapsed |