Search Images Maps Play YouTube News Gmail Drive More »
Sign in
Screen reader users: click this link for accessible mode. Accessible mode has the same essential features but works better with your reader.

Patents

  1. Advanced Patent Search
Publication numberUS3599245 A
Publication typeGrant
Publication dateAug 17, 1971
Filing dateJun 23, 1969
Priority dateJun 26, 1968
Also published asDE1931888A1
Publication numberUS 3599245 A, US 3599245A, US-A-3599245, US3599245 A, US3599245A
InventorsBlatchford Brian G
Original AssigneeBlatchford & Sons Ltd
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Artificial leg having a preset automatic friction band tension control
US 3599245 A
Abstract  available in
Images(2)
Previous page
Next page
Claims  available in
Description  (OCR text may contain errors)

United States Patent Inventor App]. Nu. Filed lzilclitctl Assigncc Priority Brian G. Blatchlord Basingstoke, England June 23. I969 Aug. I7. I97] v (Thus. A. lllalchlord & Sons Limited Basingstolte. England June 26, 1968 Great Britain ARTIFICIAL LEG HAVING A PRESET AUTOMATIC FRICTION BAND TENSION CONTROL 4 Claims, 3 Drawing Figs.

-U.S. Cl 3/28, 3/29.3/1.2 Int. Cl A61! l/04, A6lf 1/08 [50] Field of Search 3/11 2 22-29 56] References Cited FOREIGN PATIENTS 233,950 5/I925 Great Britain 3/27 779,087 I 7/1957- Great Britain 3/23 Primary Examiner- Richard A. Gaudet Assistant ExaminerRonald L. Frinks AltomeyFinnegan, Henderson & Farabow ABSTRACT: An artiiicial leg in which flexion about the knee axis is controlled in known manner by knee control mechanism of the kind having a friction band looped around a drum, the drum being connected to the shin of the leg and the friction band to the thigh. Wear in the knee control mechanism, and bedding down" of its component parts, is compensated by a preset clock-type coil spring, which automatically adjusts tension applied to the friction band.

PATENTEU Ausl 1 as?! SHEET 1 OF 2 PATENTEUAUGHIBYI 7 34599245 SHEET 2 [1F 2 ARTIFICIAL LEG HAVING A PRESET AUTOMATIC FRICTION BAND TENSION CONTROL BACKGROUND OF THE INVENTION This invention relates to an artificial leg.

British Pat. No. 779,087 discloses a knee control mechanism which has proved successful in use for a number of years; this control mechanism gives a mechanical control of knee flexion and in particular prevents-flexion, or prevents further flexion from an already flexed state, when an increased load is applied to the artificial leg. This prevents collapse of the knee caused by uncontrolled flexion, while permitting a desirable degree of flexion during normal use.

British Pat. No. 982,527 discloses a pneumatic swing phase control mechanism which in known manner controls knee flexion, but does not, and is not intended to, prevent collapse of the knee.

It is known to use both the above-described mechanism in the same artificial leg.

In the knee control mechanism referred to above, control of flexion is by a constant friction control which can be varied by the patient by manually adjusting for example a knurled wheel. This constant friction control provides for damping of the flexion. When the pneumatic swing phase control unit referred to above is also incorporated in the leg, thiscontrol unit takes over the damping function, and it has been found that manual adjustability of the constant friction control is unnecessary.

Nevertheless, in an artificial leg having both the knee control mechanism and the pneumatic swing phase control, when the feature of manual adjustability is omitted from the said control mechanism, it is found that some loss of operating efficiency occurs in the knee control mechanism. This is caused by wear in the knee control mechanism, and also by the bedding down" or settingling" of its parts.

It isan object of this invention to avoid as far as possible this loss of operating efficiency.

SUMMARY OF THE INVENTION According to this invention there is provided an artificial leg in which flexion of upper and lower parts of the leg about a knee axis is controlled by knee mechanism, the knee mechanism including a drum connected to and movable with the said lower part and a friction band around the drum and connected to and movable with the said upper part, wherein a predetermined tension in the band is maintained by preset automatic compensating means.

The friction band may be looped around an adjustably movable member having a threaded bore in which is mounted a threaded rod which is rotatable by a preset clock-type spring coiled around the axis of the threaded rod. A clock-type coil spring occupies little space, and can be readily pretensioned during assembly of the knee mechanism. Also, although pretensioned the friction produced by it is very small.

Preferably the end of the threaded rod remote from the adjustably movable member is of square cross section, in which case the inner coil of the clock-type spring is also square and fits closely about the said end of the threaded rod. This provides a simple manner of connecting the spring operatively to the threaded rod.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. I is a central vertical cross section of an artificial leg in accordance with the invention, with some parts shown in side elevation; v

FIG. 2 is an enlarged central vertical cross section of part of FIG. 1; and

FIG. 3 is a schematic detail, partly in top plan and partly in horizontal cross section.

. invention is applicable to various well-known constructions of 1 DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to the drawings, it should be understood that the artificial leg and that accordingly only those parts strictly relevant to an understanding of the invention have been illustrated. Persons skilled in the art will readily understand how the parts described below can be embodied in an artificial leg.

A knee mechanism, indicated generally by 1, includes a frame 2 by means of which the knee mechanism 1 is fitted to the lower end of a thigh (not shown). A conventional knee enclosing cup" is indicated at 3 and has a slot 3A. The knee axis, about which relative flexion between the thigh and shin occurs, is indicated at 4. A knee shaft 5 is fixed at its ends to the upper ends (one of which is seen at 6A) of a cradle or framework 6, the lower end of which is formed as a socket 6B. In the socket 6B is fixed the upper end of a well-known shin tube 6C. The framework 6 also includes side members (one of which is seen at 7A), a rear member 78, and a transverse or front member 7C.

Known pneumatic swing phase control mechanism is indicated generally at 8. It has a body part 8A pivotally connected at 88 to the framework 6. It has a piston rod 8C extending through the slot 3A and pivotally connected at 8D to the knee mechanism frame 2. In known manner, as previously mentioned, the mechanism 8 controls knee flexion, that is, it controls relative movement of the shin and thigh about the knee axis 4. British Pat. No. 982527 discloses a suitable swing phase control mechanism.

Integral with the knee shaft 5 is a drum 5A around which extends a friction band 9 in known manner. The band 9 also passes around members 9A, 9B and finally round a member 10 which is adjustably movable for varying the tension in the A band 9.

Referring to FIG. 2, the member 10 has a threaded bore 10A in which is received a rotatable threaded rod 11. The band 9 has an aperture 9C through which the rod 11' passes. The rod 11 is rotatably mounted in a bushing 11A in the frame 2. When the rod 11 is rotated, the member 10 is adjusted up or down, to adjust the tension in the band 9. The upper end 118 of the rod 11 (i.e. the end remote from the member 10) is of generally square cross section, see also FIG. 3. The rod 11 has a flange 11C which rests on the bushing 11A.

Coiled around the rod 11 is a clock-type spring 12, whose innermost coil 12A is generally square (see FIG. 3) and fits closely about the square upper end 11B of the rod 11. The outer end of the spring 12 is anchored to a pin 12B fixed in the frame 2. During assembly, the innermost coil 12A is fitted over the end 11B. Then the spring is preset (or pretensioned) by rotating its outer end say two or three times. Then the outer end is hooked over the pin 128. In this condition it will be understood that the spring always exerts torque on the rod 11 and the arrangement is such that the spring always tends to turn the rod 11 in that direction which will cause the member 10 to be moved upwardly on the rod 11. In this way, any slackness or stretching which may gradually occur in the friction band 9 during use, is automatically compensated.

When the spring 12 has been fitted and pretensioned a cover plate 13 is fitted over it, the cover plate 13 being retained by a screw 13A.

The clock-type spring 12 is desirably of comparatively low rate so that the torsion exerted by it remains reasonably constant over a wide range of rotation of the rod ll. Friction in the spring is very small. By way of example, the spring can be of steel, have 18 working coils, and require three turns of its outer end to produce a torque of 0.15 pounds per inch.

I claim:

1. An artificial leg having an upper part, a lower part, and knee mechanism controlling flexion of the upper and lower parts about a knee axis, the knee mechanism including a drum connected to and movable with the lower part, and a friction band around the drum and connected to and movable with the upper part, characterized in that a predetermined substantially constant tension in the band is maintained by preset automatic compensating means responsive to slackening or stretching in the friction band.

2. An artificial leg according to claim 1 in which the friction band is looped around an adjustably movable member having a threaded bore, said compensating means comprising a rotatable, threaded rod mounted in the threaded bore and rotatable by a preset clock-type spring coiled around the axis I of the threaded rod.

Patent Citations
Cited PatentFiling datePublication dateApplicantTitle
GB233950A * Title not available
GB779087A * Title not available
Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US5472410 *Apr 22, 1994Dec 5, 1995Deroyal/Lmb, Inc.Adjustable flexion and extension joint orthoses
US5683353 *Nov 29, 1995Nov 4, 1997Deroyal/Lmb, Inc.Adjustable flexion and extension joint orthoses
US7942907 *Aug 25, 2010May 17, 2011Richelsoph Marc EPolyaxial screw assembly
US8109973 *Oct 30, 2006Feb 7, 2012Stryker SpineMethod for dynamic vertebral stabilization
US8137385 *Oct 30, 2006Mar 20, 2012Stryker SpineSystem and method for dynamic vertebral stabilization
US8226687Oct 21, 2009Jul 24, 2012Stryker SpineApparatus and method for dynamic vertebral stabilization
US8529603Jan 24, 2012Sep 10, 2013Stryker SpineSystem and method for dynamic vertebral stabilization
US8623059Jan 13, 2012Jan 7, 2014Stryker SpineSystem and method for dynamic vertebral stabilization
US8974499Sep 16, 2009Mar 10, 2015Stryker SpineApparatus and method for dynamic vertebral stabilization
US9421041Oct 2, 2009Aug 23, 2016Marc E. RichelsophPolyaxial screw assembly
US9433440Apr 8, 2010Sep 6, 2016Intelligent Implant Systems LlcPolyaxial screw assembly
US9445846Dec 10, 2013Sep 20, 2016Stryker European Holdings I, LlcSystem and method for dynamic vertebral stabilization
US9456851Mar 10, 2011Oct 4, 2016Intelligent Implant Systems, LlcSpinal implant
US9486244Mar 6, 2015Nov 8, 2016Stryker European Holdings I, LlcApparatus and method for dynamic vertebral stabilization
US9526531Apr 27, 2015Dec 27, 2016Intelligent Implant Systems, LlcPolyaxial plate rod system and surgical procedure
US9603629Dec 24, 2008Mar 28, 2017Intelligent Implant Systems LlcPolyaxial screw assembly
US20070123866 *Oct 30, 2006May 31, 2007Stryker SpineSystem and method for dynamic vertebral stabilization
US20070135815 *Oct 30, 2006Jun 14, 2007Stryker SpineSystem and method for dynamic vertebral stabilization
US20100010544 *Sep 16, 2009Jan 14, 2010Stryker SpineApparatus and method for dynamic vertebral stabilization
US20100042153 *Oct 21, 2009Feb 18, 2010Fallin T WadeApparatus And Method For Dynamic Vertebral Stabilization
US20100312289 *Aug 25, 2010Dec 9, 2010Richelsoph Marc EPolyaxial screw assembly
WO2011080556A2Nov 18, 2010Jul 7, 2011Rizzoli Ortopedia S.P.A.Prosthesis structure for lower-limb amputees
WO2014197236A1 *May 27, 2014Dec 11, 2014Advanced Suspension Systems, LlcAttachment system for prosthetic device
Classifications
U.S. Classification623/45, 623/26, 623/46
International ClassificationA61F2/64, A61F2/60
Cooperative ClassificationA61F2/64
European ClassificationA61F2/64