Title:
DRIVER/FASTENER INTER-ENGAGEMENT SYSTEM
Document Type and Number:
WIPO Patent Application WO/2018/073153
Kind Code:
A9
Abstract:
Embodiments of the present invention provide a screw and driver system comprising a range of screws and a driver for said range. Each screw comprises a head having a driving recess in its surface for engagement by said driver. Each recess has a recess longitudinal axis. The recess of larger screws in the range has a plurality of superimposed recess-tiers of decreasing size with increasing depth from said surface, each recess-tier except the smallest having substantially parallel driving surfaces substantially parallel said recess longitudinal axis. The driving head of the driver has a driver longitudinal axis and a plurality of superimposed drive-tiers of decreasing size towards a tip of the driver, each drive-tier except the smallest having substantially parallel driving surfaces substantially parallel said longitudinal axis. The driver and recess are shaped so that, when the driver is engaged with the recess of any screw in said range, torque applied to the driver is transmitted to the screw through said driving surfaces. The smallest recess-tier of larger screws has a mouth in a floor of an adjacent recess-tier and has recess flanks that are all tapered from the mouth towards the recess longitudinal axis at a recess taper angle between 1.91 and 6.85°. The smallest drive-tier of the driver has a root in a base of an adjacent drive-tier and has drive flanks that are all tapered from the root towards the driver longitudinal axis at a tier taper angle between minus 1.5 and plus 2.5° difference with respect to said recess taper angle. The diameter of the drive-tier at the root and the diameter of the recess-tier at the mouth are such that, on insertion of said driver head in the screw recess, said drive and recess flanks inter-engage to deform and stick together through frictional engagement before said base engages said floor.
Inventors:
CONE BENJAMIN (US)
DRAKE HAMILTON (US)
O'HEARN DANIEL (CA)
DRAKE HAMILTON (US)
O'HEARN DANIEL (CA)
Application Number:
PCT/EP2017/076299
Publication Date:
June 14, 2018
Filing Date:
October 16, 2017
Export Citation:
Assignee:
CONS FASTENERS LLC A DELAWARE LLC (US)
HGF LTD (GB)
HGF LTD (GB)
International Classes:
F16B23/00; B25B15/00; B25B23/10
Attorney, Agent or Firm:
HGF LIMITED (GB)
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