Screw unit to join semi-rigid mats together
AssigneeCryotherm Limited
InventorWalter Bronn
Life of this patent
Estimating the term…
Abstract
A screw unit with a shaft (1) and an enlargement at one end, to join together semi-rigid mats, consisting for example of mineral fibers or foam material, has the shaft (1) consisting of a wire helix (W) wound in corkscrew fashion and continuing at the one end as a spiral winding forming the headpiece (2), with the helical slope (.alpha.) of the wire helix (W) adjacent the headpiece (2) being smaller than the helical slope (.beta.) in the region of a point (5) at the other end of the shaft (1).
Claims17
A screw unit for joining together semi-rigid mats, consisting for example of mineral fibers or foam material, comprising a shaft and an enlargement at one end of said shaft, with said shaft consisting of a wire helix wound in corkscrew fashion, having a longitudinal axis, and continuing at said one end into said enlargement as a spiral winding forming a headpiece, with the helix angle of said wire helix adjacent said headpiece and with respect to said longitudinal axis being smaller than the helix angle of said wire helix in the region of the other end of said shaft, and with at least a portion of said enlargement extending orthogonally with respect to said longitudinal axis and having a relatively short axial length such that said enlargement is prevented from projecting beyond an adjacent surface of one of said mats.
A screw unit for joining together semi-rigid mats, consisting for example of mineral fibers or foam material, comprising a shaft and an enlargement at one end of said shaft, with said shaft consisting of a wire helix wound in corkscrew fashion and having a longitudinal axis, continuing at said one end into the helix angle of said wire helix adjacent said headpiece and with respect to said longitudinal axis being smaller than the helix angle of said wire helix in the region of the other end of said shaft wherein said headpiece is fashioned as a frustrum of a shallow cone.
A screw unit for joining together semi-rigid mats, consisting for example of mineral fibers or foam material, comprising a shaft and an enlargement at one end of said shaft, with said shaft consisting of a wire helix wound in corkscrew fashion and having a longitudinal axis, continuing at said one end into said enlargement as a spiral winding forming a headpiece, with the helix angle of said wire helix adjacent said headpiece and with respect to said longitudinal axis being smaller than the helix angle of said wire helix in the region of the other end of said shaft, wherein at least one abutment surface is provided on said spiral winding for engagement by a tool to apply a fastening torque to said screw unit and said headpiece is wound from outside to inside and said abutment surface is provided at said inside.
A screw unit for joining together semi-rigid mats, consisting for example of mineral fibers or foam material, comprising a shaft and an enlargement at one end of said shaft, with said shaft consisting of a wire helix wound in corkscrew fashion and having a longitudinal axis, continuing at said one end into said enlargement as a spiral winding forming a headpiece, with the helix angle of said wire helix adjacent said headpiece and with respect to said longitudinal axis being smaller than the helix angle of said wire helix in the region of the other end of said shaft, wherein at least one abutment surface is provided on said spiral winding for engagement by a tool to apply a fastening torque to said screw unit and an innermost turn of said spiral winding is constructed as an engagement opening for said tool.
Dependencies are inferred from the claim text.