Patent ID: 6684754
Filing Date: 2004-02-03
Classification: A61F,B25J,F15B

Abstract:
An artificial muscle analog for mimicking an organic muscle, substantially disposed within a void or cavity, defined by an interior surface, within a first substantially rigid member or exoskeletal bone, comprising;a substantially flexible artificial tendon or cable of diameter substantially less than the dimensions of said cavity, having a first fixed end and a second free end, disposed substantially within said cavity; a plurality of cable constraint points for constraining the motion of said cable, each located on said interior surface, including at least a pair of constraint points comprising a first fixed cable constraint point and a second sliding cable constraint point; wherein said fixed end of said cable is affixed to said bone at said fixed constraint point; a low-friction roller, guide or cable positioning means disposed near said sliding cable constraint point, whereby said cable is constrained to pass near said point, said means nevertheless allowing said cable to slide freely past said point with relatively little friction; whereby a shortest cable path is defined, it being the unobstructed path followed by said cable from said first point to said second point within said cavity when said cable is taut; an inflatable bladder, affixed to said interior surface and placed such that said bladder forces said cable to deviate from said shortest cable path, when inflated; and a valve or connection means whereby said bladder may be connected to a pressurized fluid; wherein the pressure of said fluid may be greater than the pressure of said bladder; whereby fluid is forced into said bladder when said valve is connected, thereby inflating the bladder; whereby said inflating bladder forces said cable to deviate from said shortest path; whereby the length of cable between said first and second constraint points is forced to increase; whereby, said cable being fixedly constrained at its first end to said first constraint point, and slidingly constrained at said second constraint point, said free end of said cable is pulled in under tension; whereby said artificial muscle acts like said organic muscle when tensed; and wherein the pressure of said fluid may be less than the pressure of said bladder; whereby fluid is forced out of said bladder when said valve is connected, thereby deflating said bladder; whereby said deflating bladder allows said cable to approach said shortest path; whereby the length of cable between said first and second constraint points is allowed to decrease; whereby, said cable being fixedly constrained at its first end to said first constraint point, and slidingly constrained at said second constraint point, said free end of said cable may be pulled out, under reducing tension; whereby said artificial muscle acts like said organic muscle when relaxed; whereby said artificial muscle analog mimics said organic muscle.