Patent Application: US-38005509-A

Abstract:
the device described herein is an electro - magnet based telescoping artificial muscle actuator . this device uses a centrally located electromagnet which acts on permanent magnets and ferrous components housed within telescoping sections of this device . this device is intended to be linked into chains of other identical devices , with those chains then linked into bundles . this arrangement allows devices of this type simulate the action and control mechanisms of natural muscle . this device is intended for use in prosthetic , robotic , and implantable applications .

Description:
the preferred embodiment of this device is as follows . the central component of this device is a solid ferrous core electromagnet ( 1 ). this solid core should be spindle shaped . this electromagnet should be housed in a nonferrous casing ( 2 ) that allows for attachment of the two parts of telescoping component 1 ( 3 ). each part of component 1 ( 3 ) should be mirrored around the central electromagnet and be fitted into the electromagnet housing by the use of screw threads or with screws with corresponding countersunk threaded holes . power leads ( 4 ) for the electromagnet ( 1 ) should pass through the electromagnet housing and other components . all telescoping components of this device occur in pairs mirrored around the central electromagnet . component 1 ( 3 ) is open at one end with a small lip protruding towards the center of the opening . this lip is meant to stop the motion of telescoping component 2 ( 5 ) by making contact with the permanent magnet base ( 6 ) of component 2 . component 1 ( 3 ) must have a lip facing away from its opening to prevent motion of telescoping component 4 ( 9 ). component 2 ( 5 ) is housed inside component 1 ( 3 ). component 2 ( 5 ) is comprised of a nonferrous hollow cylinder with a permanent magnet ( 6 ) attached to one side and with the other left open with a small lip protruding towards its center to contain telescoping component 3 ( 7 ). the polarity of the permanent magnet of component 2 ( 5 ) should be oriented opposite to the polarity of the central electro magnet for each mirrored component . the surfaces of the magnets ( 6 ) of component 2 ( 5 ) which face each other should have opposing polarities . contained within component 2 ( 5 ) is telescoping component 3 ( 7 ). this component is solid , ferrous , and has a threaded end ( 8 ) that extends beyond the open end of component 2 ( 5 ). component 3 ( 7 ) has a lip at one end that contacts the lip of component 2 ( 5 ). component 3 ( 7 ) is not an identical mirrored pair . one unit would have internal threads at the end protruding beyond component 2 ( 5 ), and one would have external threads extending to the same distance . this orientation , along with the threads ( 11 ), of telescoping component 5 ( 10 ) allows actuators of this type to be joined together , end to end , into long chains ( fig3 ), to allow for increased force of contraction ( to be discussed in detail below ). component 5 ( 10 ) is a nonferrous hollow cylinder which has one end that extends to the height of component 3 ( 7 ). each of the units of component 5 ( 10 ) would have oppositely oriented threads ( 11 ) extending from the height of components 1 , 2 and 4 , to the height of component 3 . its opposite end has an internal lip that contacts telescoping component 4 ( 9 ). component 4 ( 9 ) has a lip facing outward at its end closest to the threaded region of the device . it has a lip facing the center of the device which contacts component 1 ( 3 ). there is a spring providing compression resistance in between components 5 and 4 ( 13 ). component 4 ( 9 ) is located inside component 5 ( 10 ). it has a lip facing the center of the device which interacts with the outer lip of component 1 ( 3 ). there is a spring located between component 4 and component 1 ( 12 ). connections to a power source should be a simple positive / negative plug that passes in between all outer telescoping layers and does not interfere with their contraction . this plug should be built into the housing of the central electro magnet . threaded regions do not occur in mirrored pairs . one should have a male thread and one a female to allow for actuators to be connected end to end . the preferred dimensions of this device are that the central magnet should have a sufficient number of coils to produce at least 0 . 5 to 1 lb of force . the length of this device should be anywhere from one to one and a half times its diameter when contracted fully . the contracted length to width ratio pictured in fig1 a and 1b is 1 : 1 . the device pictured in all figures has a diameter of 2 cm . dimensions of this device should be varied depending on the specific application for which it is used . this device must be capable of contracting to at least one half of its full extended length . this device must resist contraction and tend to return to its contracted state if no internal or external forces are applied . each actuator of this type is intended to be joined end to end with other similar actuators , forming actuator chains ( fig3 ). further bundling of these actuator chains ( fig4 ) is necessary to provide effective control of contraction strength and length . increasing the amplitude of current supplied to this device will increase its contractile strength . increasing the frequency of signals to this device accounts for an increase in duration and degree of contraction , with each signal control resulting in an all or nothing action of the actuator . additional units to a chain of actuators and additions of actuator chains are intended to be the principle method of increasing the functional strength of contraction generated by this type of actuator . order of assembly of this device is as follows : telescoping component 3 is fitted into the cylindrical portion of telescoping component 2 , and then the magnet ( 6 ) is attached to component 2 . components 2 and 3 are inserted into telescoping component 1 . a spring ( 13 ) is then fitted around component 1 . component 1 is then fitted into telescoping component 4 . a spring ( 12 ) is then placed around component 4 . component 4 is then fitted into telescoping component 5 . this should be done for each mirrored section of telescoping components , and then component 1 of each mirrored pair should be attached to the electromagnet housing ( 2 ). actuator components can then be secured into long chains by means of threads . chains of actuators should be bundled together to create an artificial muscle apparatus ( fig4 ). the strength of contraction of these bundles is dependent upon the amplitude of current supplied to each actuator , the number of actuators in a chain , and the number of chains in the bundle which are activated . duration of contraction ( and length of contraction , depending on the load on the system ) is dependent upon the number of control signals received per unit time . bundles of chains of actuators may be linked together by their ends to create a single contractile unit . a unit of this nature should be surrounded by a flexible , biocompatible , sheath ( 14 , shown as a cut - away ) to allow for implantation . this sheath should have terminal components ( 15 ) that can be affixed to biological structures ( such as tendons or bones ), as well as to the ends of the contractile unit . components of this device should be manufactured using standard milling and / or injection molding techniques . reference to sequence listing , a table , or a computer program listing compact disc appendix ( 1 ) carroll , kevin ( 2006 ). prosthetics and patient management : a comprehensive clinical approach . slack incorporated . isbn 1556426712 , 9781556426711 ( 3 ) u . s . pat . no . 6 , 781 , 284 ( 2004 aug . 24 ) ronald e . pelrine , electroactive polymer transducers and actuators ( 4 ) u . s . pat . no . 6 , 223 , 648 ( 2001 may 1 ) joel r . erickson , artificial muscle actuator assembly anthony , catherine parker ( 1975 ). “ textbook of anatomy and physiology ” 9 th edition . c . v . mosby company gray , henry ( 1930 ). “ anatomy of the human body ” 22 nd edition . philadelphia : lea and febiger martini , frederic h . 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