US 5,331,861 AGranted

Rotating drive magnetically coupled for producing linear motion

OwnerBenjamin Joffeinventor

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Abstract

A rotatable drive mechanism for producing linear motion of an object includes driving and driven members, one of which is elongated, and which act cooperatively through frictional engagement to produce longitudinal motion of the driven member. It also includes a magnetic coupling having at least first and second magnetizable members with mutually facing flat annular surfaces, a set of balls disposed in a generally annular arrangement between those flat surfaces, and magnetic means attracting the magnetizable members to each other. Respective ends of the magnetic coupling are fixedly secured to the driven member and to the object, respectively. Since the elements of the magnetic coupling, in and of themselves, would permit relative rotation of parts, which is undesired, provision is also made for restraining the undesired rotation of any part of the magnetic coupling. In a particular embodiment a second magnetic coupling, without balls between magnetizable members, is also used in opposing relation to the first coupling.

Claims21

Dependent claims

A rotatable drive mechanism for producing linear motion of an object, while minimizing the effects of undesired lateral movements of the drive mechanism itself, comprising:

(a) means for converting rotating motion to linear motion, including an elongated drive member and a cooperating structure disposed laterally to said elongated drive member which frictionally engages said elongated drive member such that driven rotation of either of them causes one to move relative to the other in a direction longitudinally of said drive member;
(b) fixed support means mounting a first one of said elongated drive member and said cooperating structure for rotation relative thereto, and also mounting the object for longitudinal slidable motion relative to said fixed support means in a direction longitudinally of said elongated drive member;
(c) drive means adapted to drive said first one of said drive member and said cooperating structure in rotation relative to said fixed support means;
(d) means restraining the other one of said elongated drive member and said cooperating structure against rotation relative to said fixed support;
and
(e) magnetic means coupling said first one of said drive member and said cooperating structure to the object, including:
(1) a first magnetizable member fixedly secured to said first one and having a substantially flat annular surface which lies in a plane substantially perpendicular to the longitudinal axis of said elongated drive member,
(2) a second magnetizable member fixedly secured to the object and having a substantially flat annular surface which faces toward the first magnetizable member and which lies in a plane substantially parallel to the plane of the flat annular surface of the first magnetizable member, and
(3) a set of balls disposed in a generally annular arrangement between the annular surfaces of said two magnetizable members;
and
(f) means for establishing magnetic attraction between the first and second magnetizable members, to forcibly draw the magnetizable members toward one another and forcibly capture the balls longitudinally between the two annular surfaces and cause the balls to be:
with respect to longitudinal movement, forcibly constrained by said surfaces, and
with respect to transverse movement, free for transverse rolling movements in response to transverse relative displacements of said surfaces;
wherein said first and second magnetizable members:
forcibly transmit longitudinal motion from the drive means through the balls to the object, and
are decoupled with respect to transverse relative displacements, which displacements are accommodated by said transverse rolling motion of the balls;
whereby said forcible transmission of longitudinal motion through the balls is substantially unaffected by lateral movements which may result from wobbling or vibration of said elongated drive member.

14 more elements

A rotatable drive mechanism for producing linear motion of an object while minimizing the effects of undesired lateral movements of the drive mechanism itself, comprising:

(a) means for converting rotating motion to linear motion, including a drive structure and an elongated driven member, said drive structure frictionally engaging said elongated driven member and adapted when driven to move said elongated driven member longitudinally;
(b) fixed support means mounting said drive structure for rotation relative thereto, and also mounting the object for longitudinal slidable motion relative to said drive structure;
(c) magnetic means coupling said drive structure to the object, including:
(1) a first magnetizable member fixedly secured to said elongated driven member and having a substantially flat annular surface and which lies in a plane substantially perpendicular to the longitudinal axis of said elongated drive member,
(2) a second magnetizable member fixedly secured to the object and having a substantially flat annular surface which faces toward and lies in a plane substantially parallel to the flat annular surface of the first magnetizable member, and
(3) a set of balls disposed in a generally annular arrangement between the annular surfaces of said two magnetizable members;
and
(d) means restraining said elongated driven member against rotation relative to said drive structure;
and
(e) means for establishing magnetic attraction between the first and second magnetizable members, to forcibly draw the magnetizable members toward one another and forcibly capture the balls longitudinally between the two annular surfaces and cause the balls to be:
with respect to longitudinal movement, forcibly constrained by said surfaces, and
with respect to transverse movement, free for transverse rolling movements in response to transverse relative displacements of said surfaces;
wherein said first and second magnetizable members of the apparatus;
forcibly transmit longitudinal motion from the drive means through the balls to the object, and
are decoupled with respect to transverse relative displacements, which displacements are accommodated by said transverse rolling motion of the balls;
whereby said forcible transmission of longitudinal motion through the balls is substantially unaffected by lateral movements which may result from wobbling or vibration of said elongated driven member.

13 more elements

A rotatable drive mechanism for producing linear motion of an object while minimizing the effects of undesired lateral movements of the drive mechanism itself, comprising:

(a) means for converting rotating motion to linear motion, including a drive structure and an elongated driven member, said drive structure frictionally engaging said elongated driven member and adapted when driven to move said elongated driven member longitudinally;
(b) fixed support means mounting said drive structure for rotation relative thereto, and also mounting the object for longitudinal slidable motion relative to said drive structure;
(c) magnetic means coupling said drive structure to the object, including:
(1) a first magnetizable member fixedly secured to said elongated driven member and having a substantially flat annular surface which lies in a plane perpendicular to the longitudinal axis of said elongated drive member,
(2) a second magnetizable member having a substantially flat annular surface facing away from the object and which lies in a plane substantially perpendicular to the direction of longitudinal slidable motion of the object,
(3) a first set of balls disposed in a generally angular arrangement between the annular surfaces of said first and second magnetizable members,
(4) a third magnetizable member fixedly secured to the object and having a substantially flat annular surface facing away from the object and which lies in a plane perpendicular to the direction of longitudinal slidable motion of the object, said second magnetizable member also having a flat annular surface facing toward the object, and
(5) a second set of balls disposed in a generally annular arrangement between the annular surfaces of said second and third magnetizable members;
and
(d) means restraining said elongated driven member against rotation relative to said drive structure;
at least one of said magnetizable members being magnetized whereby said balls in conjunction with said magnetizable members reliably transmit longitudinal motion to the object substantially unaffected by lateral movement which may result from wobbling or vibration of said elongated driven member.

8 more elements

Dependencies are inferred from the claim text.

Facts

Application: 07/952,471Filed 28 Sep 1992 · continuation
Priority: 4 Jun 1990
Granted: 26 Jul 1994
Term ends: Not estimatedThe source records don’t support an estimate.

Classification14 codes

F16H 25/24
Screw mechanisms: elements essential to such mechanisms, e.g. screws, nuts
B23Q 5/408
By feed shaft, e.g. lead screw: nut bearings therefor
F16C 19/10
With bearing balls essentially of the same size in one or more circular rows: for axial load mainly
F16C 29/002
Bearings for parts moving only linearly: elastic or yielding linear bearings or bearing supports