Electromagnetic helical spring clutch

A magnetically actuated clutch assembly including in combination a first clutch member, a second clutch member, said first and second clutch members being supported for rotary movement around a common axis, a helical spring having a rectangular coil cross section, means for securing one end of said spring to said first clutch member for rotation therewith around said axis, a portion of said spring having a free end surrounding said second clutch member, the arrangement being such that said spring portion rotates relative to said second clutch member in the absence of a restraint against the movement of said free end, one of said spring and said second member being formed of magnetic material, a U-shaped armature of magnetic material having a base and a pair of legs forming pole pieces, said legs having end portions shaped to match the curvature of said spring, means mounting said armature for movement toward said second clutch member with said legs adjacent said surrounding spring portion, a coil carried by said base, and means for energizing said coil to cause said legs to move toward said second clutch member to exert a retarding force on said free end.

A magnetically actuated clutch assembly including in combination a first clutch member, a second clutch member comprising a magnetic material, said first and second clutch members being supported for rotary movement around a common axis, a helical spring, means for securing one end of said spring to said first clutch member for rotation therewith around said axis, a portion of said spring having a free end surrounding said second clutch member, the arrangement being such that said spring portion rotates relative to said second clutch member in the absence of a restraint against the movement of said free end, one of said spring and said second member being formed of magnetic material, a U-shaped armature of magnetic material having a base and a pair of legs forming pole pieces, means mounting said armature for movement toward said second clutch member with said legs adjacent said surrounding spring portion, a coil carried by said base, and means for energizing said coil to cause said legs to move toward said second clutch member to exert a retarding force on said free end.

A clutch including in combination first and second rotary clutch members, a helical spring secured to said first member with a portion of said spring surrounding said second member, said spring portion being free to rotate relative to said second member in the absence of a retarding force on said spring portion, at least one of said spring and said second member comprising a magnetic material, an electromagnet having a pair of pole pieces of opposite polarity, said electromagnet being formed with portions defining a slot, means including a pin engaging said slot for supporting said electromagnet for movement toward said second member with said pole pieces adjacent said surrounding spring portion, and means for energizing said electromagnet to cause said pole pieces to move toward said second clutch member to exert a retarding force on said surrounding spring portion.

A clutch including in combination first and second rotary clutch members, a helical spring secured to said first member with a portion of said spring surrounding said second member, said spring portion being free to rotate relative to said second member in the absence of a retarding force on said spring portion, at least one of said spring and said second member comprising a magnetic material, an electromagnet having a pair of pole pieces of opposite polarity, means for supporting said electromagnet for movement toward said second member with said pole pieces adjacent said surrounding spring portion while preventing the movement of said electromagnet more than a predetermined distance away from said second member, and means for energizing said electromagnet to cause said pole pieces to move toward said second clutch member to exert a retarding force on said surrounding spring portion.

A clutch including in combination first and second rotary clutch members, a helical spring secured to said first member with a portion of said spring surrounding said second member, said spring portion being free to rotate relative to said second member in the absence of a retarding force on said spring portion, at least one of said spring and said second member comprising a magnetic material, an electromagnet having a pair of pole pieces of opposite polarity, means for supporting said electromagnet for movement toward said second member with said pole pieces adjacent said surrounding spring portion, and means for energizing said electromagnet to cause said pole pieces to move toward said second clutch member to exert a retarding force on said surrounding spring portion.

A clutch including in combination first and second rotary clutch members, a helical spring secured to said first member with a portion of said spring surrounding said second member, said spring portion being free to rotate relative to said second member in the absence of a retarding force on said spring portion, at least one of said spring and said second member comprising a magnetic material, an electromagnet having a pair of pole pieces of opposite polarity, means for supporting said electromagnet for movement toward said second member with said pole pieces adjacent said surrounding spring portion at locations spaced circumferentially about said spring portion, and means for energizing said electromagnet to cause said pole pieces to move toward said second clutch member to exert a retarding force on said surrounding spring portion.

A magnetically actuated clutch including in combination first and second rotary clutch members, a helical spring secured to said first member with a portion of said spring surrounding said second member, said spring portion being free to rotate relative to said second member in the absence of a retarding force on said spring portion, at least one of said spring and said second member comprising a magnetic material, means including a pair of pole pieces of opposite polarity disposed adjacent said surrounding spring portion at locations spaced circumferentially about said spring portion for forming a magnetic circuit with said magnetic material, at least one of said pole pieces being movable toward said second member, and means for energizing said magnetic circuit to cause said one pole piece to move toward said second clutch member to exert a retarding force on said surrounding spring portion.

A magnetically actuated clutch including in combination first and second rotary clutch members, a helical spring secured to said first member with a portion of said spring surrounding said second member, said spring portion being free to rotate relative to said second member in the absence of a retarding force on said spring portion, at least one of said spring and said second member comprising a magnetic material, means including a pole piece movable toward said surrounding spring portion and said second member for forming a magnetic circuit with said magnetic material, and means for energizing said magnetic circuit to cause said pole piece to move toward said second clutch member to exert a retarding force on said surrounding spring portion.