Wire accumulator

In a double block accumulator of the type comprising a driven lower block for drawing wire and an upper coaxial block rotatable relative to the lower block where the wire is first wound on the lower block and then wound on the upper block in the reverse direction, pressure responsive frictional coupling means disposed between said blocks, and means for varying the coupling pressure on said coupling means;

• said means for varying the pressure being effective to vary the pressure at a predetermined rate with movement thereof, means for limiting the coupling pressure that can be applied to said coupling means, and means responsive to the coupling pressure reaching a predetermined value for changing the rate at which pressure is increased with movement of said varying means to a lower value.

In a double block accumulator of the type comprising a driven lower block for drawing wire and an upper coaxial block rotatable relative to the lower block where the wire is first wound on the lower block and then wound on the upper block in the reverse direction, the upper block being rotatably mounted about an extension of a drive shaft of the lower block, pressure responsive frictional coupling means disposed between said blocks, and means for varying the coupling pressure on said coupling means;

• said means for varying the coupling pressure comprising first and second members mounted to said shaft extension for relative rotation, means for restraining one of first and second members from rotation, said first and second members being threaded together whereby rotation of one of said first and second members while the other is restrained from rotation produces axial movement of the restrained member, thrust means for transmitting downward movement of said restrained member to said coupling means through said upper block, and means for limiting relative axial movement of said first and second members to thereby limit the coupling pressure that can be applied to said coupling means through said upper block to a predetermined value while still permitting relative rotation between said upper and lower blocks.

A double block accumulator of the type including a lower block on a driven shaft, an upper block rotatably mounted to an extension of said driven shaft, frictional coupling means disposed between said blocks, first and second members rotatably mounted to said shaft extension at the upper end thereof and threaded to each other, means normally holding one of said first and second members against rotation, whereby rotation of the other of said first and second members produces linear movement of the other, thrust transmitting means between said linearly movable member and said upper block whereby when said linearly movable member moves downwardly it forces said upper block downwardly to increase the pressure on said frictional coupling means between said blocks, an extension member coupled to said shaft extension at the end thereof by resilient biasing means having a predetermined force therein, said biasing means holding said extension member fast to said shaft extension so long as the axial coupling force between said blocks does not exceed said predetermined force, one of said first and second members mounted to said extension member, whereby when said coupling force exceeds said predetermined force said biasing means raises said extension member from said shaft extension.