Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
  • F16B—DEVICES FOR FASTENING OR SECURING CONSTRUCTIONAL ELEMENTS OR MACHINE PARTS TOGETHER, e.g. NAILS, BOLTS, CIRCLIPS, CLAMPS, CLIPS OR WEDGES; JOINTS OR JOINTING
  • F16B39/00—Locking of screws, bolts or nuts
  • F16B39/22—Locking of screws, bolts or nuts in which the locking takes place during screwing down or tightening
  • F16B39/24—Locking of screws, bolts or nuts in which the locking takes place during screwing down or tightening by means of washers, spring washers, or resilient plates that lock against the object
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
  • A61B17/00—Surgical instruments, devices or methods, e.g. tourniquets
  • A61B17/56—Surgical instruments or methods for treatment of bones or joints; Devices specially adapted therefor
  • A61B17/58—Surgical instruments or methods for treatment of bones or joints; Devices specially adapted therefor for osteosynthesis, e.g. bone plates, screws, setting implements or the like
  • A61B17/68—Internal fixation devices, including fasteners and spinal fixators, even if a part thereof projects from the skin
  • A61B17/84—Fasteners therefor or fasteners being internal fixation devices
  • A61B17/86—Pins or screws or threaded wires; nuts therefor
  • A61B17/8665—Nuts
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
  • A61B17/00—Surgical instruments, devices or methods, e.g. tourniquets
  • A61B17/56—Surgical instruments or methods for treatment of bones or joints; Devices specially adapted therefor
  • A61B17/58—Surgical instruments or methods for treatment of bones or joints; Devices specially adapted therefor for osteosynthesis, e.g. bone plates, screws, setting implements or the like
  • A61B17/68—Internal fixation devices, including fasteners and spinal fixators, even if a part thereof projects from the skin
  • A61B17/84—Fasteners therefor or fasteners being internal fixation devices
  • A61B17/86—Pins or screws or threaded wires; nuts therefor
  • A61B17/8695—Washers
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
  • A61B17/00—Surgical instruments, devices or methods, e.g. tourniquets
  • A61B17/56—Surgical instruments or methods for treatment of bones or joints; Devices specially adapted therefor
  • A61B17/58—Surgical instruments or methods for treatment of bones or joints; Devices specially adapted therefor for osteosynthesis, e.g. bone plates, screws, setting implements or the like
  • A61B17/88—Osteosynthesis instruments; Methods or means for implanting or extracting internal or external fixation devices
  • A61B17/8875—Screwdrivers, spanners or wrenches
  • A61B17/8877—Screwdrivers, spanners or wrenches characterised by the cross-section of the driver bit
  • A61B17/8883—Screwdrivers, spanners or wrenches characterised by the cross-section of the driver bit the driver bit acting on the periphery of the screw head
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B25—HAND TOOLS; PORTABLE POWER-DRIVEN TOOLS; MANIPULATORS
  • B25B—TOOLS OR BENCH DEVICES NOT OTHERWISE PROVIDED FOR, FOR FASTENING, CONNECTING, DISENGAGING OR HOLDING
  • B25B13/00—Spanners; Wrenches
  • B25B13/02—Spanners; Wrenches with rigid jaws
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B25—HAND TOOLS; PORTABLE POWER-DRIVEN TOOLS; MANIPULATORS
  • B25B—TOOLS OR BENCH DEVICES NOT OTHERWISE PROVIDED FOR, FOR FASTENING, CONNECTING, DISENGAGING OR HOLDING
  • B25B13/00—Spanners; Wrenches
  • B25B13/48—Spanners; Wrenches for special purposes
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
  • A61B17/00—Surgical instruments, devices or methods, e.g. tourniquets
  • A61B17/56—Surgical instruments or methods for treatment of bones or joints; Devices specially adapted therefor
  • A61B17/58—Surgical instruments or methods for treatment of bones or joints; Devices specially adapted therefor for osteosynthesis, e.g. bone plates, screws, setting implements or the like
  • A61B17/68—Internal fixation devices, including fasteners and spinal fixators, even if a part thereof projects from the skin
  • A61B17/70—Spinal positioners or stabilisers ; Bone stabilisers comprising fluid filler in an implant
  • A61B17/7001—Screws or hooks combined with longitudinal elements which do not contact vertebrae
  • A61B17/7035—Screws or hooks, wherein a rod-clamping part and a bone-anchoring part can pivot relative to each other
  • A61B17/7037—Screws or hooks, wherein a rod-clamping part and a bone-anchoring part can pivot relative to each other wherein pivoting is blocked when the rod is clamped
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
  • A61B17/00—Surgical instruments, devices or methods, e.g. tourniquets
  • A61B17/56—Surgical instruments or methods for treatment of bones or joints; Devices specially adapted therefor
  • A61B17/58—Surgical instruments or methods for treatment of bones or joints; Devices specially adapted therefor for osteosynthesis, e.g. bone plates, screws, setting implements or the like
  • A61B17/68—Internal fixation devices, including fasteners and spinal fixators, even if a part thereof projects from the skin
  • A61B17/84—Fasteners therefor or fasteners being internal fixation devices
  • A61B17/86—Pins or screws or threaded wires; nuts therefor
  • A61B17/8665—Nuts
  • A61B2017/867—Nuts with integral locking or clamping means

Definitions

• the subject invention is directed generally to fasteners, and more particularly, to a ratcheting locking mechanism for threaded fasteners.
• Threaded fasteners designed to lock male and female threaded components together are well known in the art and include, for example, lock washers, blind thread bores filled with resilient inserts and screw thread profiles that deform when tightened. Fasteners with self-locking accessories such as cotter pins and lock wires are also known. Other examples of self-locking threaded fasteners are disclosed in U.S. Patent No. 5,460,468 to DiStacio on October 24, 1995; U.S. Patent No. 5,538,378 to Van der Drift on July 23, 1996; and U.S. Patent No. 5,713,708 to Van der Drift et al. on February 3, 1998, each of which is incorporated herein by reference.
• the subject technology is directed to a fastening device having a fastener with a head portion and an elongated threaded body portion extending axially from the head portion.
• the fastening device also includes a lock washer and a threaded lock nut for rotatably mating with the fastener.
• the lock washer has a lower surface with a plurality of ratchet teeth extending therefrom.
• the lock washer is configured to couple to the fastener for axial movement but is fixed rotationally.
• the threaded lock nut has an upper surface defining at least one pawl arm.
• the pawl arm includes at least one pawl tooth for engagement with at least one of the plurality of ratchet teeth, and a flange extending radially outward from the pawl arm.
• the threaded lock nut may include an axially extending recessed portion between a lower surface of the threaded lock nut and the pawl arm.
• the lock washer can have an axial aperture having at least one flat inner surface corresponding to at least one longitudinally extending flat section of the threaded body portion.
• the longitudinally extending flat section is configured to mate with the flat inner surface of the lock washer to rotationally fix the lock washer when the elongated threaded body portion is inserted in the axial aperture.
• the head portion of the fastener can be a tulip head defining a transverse channel and opposing prongs.
• the axial aperture of the lock washer can also include a bar, wherein the bar extends between opposing sides of the axial aperture to define two discrete axial apertures.
• Each axial aperture can correspond to one of the respective prongs of the tulip head.
• the axial aperture of the lock washer can be radially inward of the ratchet teeth.
• the ratchet teeth can entirely cover the lower surface of the lock washer or the lower surface of the lock washer can include a surface portion without ratchet teeth defined radially between the ratchet teeth and the axial aperture.
• the fastening device can also include a tool.
• the tool can include a distal working portion forming a tapered surface to apply a removal force to temporarily lift the pawl arm away from the ratchet teeth and unthread the threaded lock nut, and a proximal end adapted to mount to a ratchet.
• the tool can include an inner diameter tier and an outer diameter tier on a distal working portion. The inner diameter tier of the tool can correspond to the axially extending recessed portion for tightening the threaded lock nut during clock-wise rotation of the tool.
• the outer diameter tier can include a tapered ramp for applying a removal force to a surface of the flange of the pawl arm to bend the pawl arm and the at least one pawl tooth away from the ratchet teeth for disengagement during counter-clockwise rotation of the tool.
• the tapered ramp may be defined in a slot defined in the outer diameter tier, and/or on a circumferentially extending flange of the outer diameter tier.
• a fixation system for coupling a rod to bone includes an elongated bone screw fastener having, a lock washer and a threaded lock nut.
• the elongated bone screw fastener includes a threaded tulip head portion defining a transverse channel and opposing prongs, and an elongated threaded body portion depending from the tulip head portion.
• the lock washer includes opposed upper and lower surfaces with a pair of discrete axial apertures extending therebetween, and ratchet teeth.
• the lock washer includes a bar extending between the pair of discrete axial apertures.
• Each discrete axial aperture is configured to receive one of the respective prongs of the tulip head portion of the elongated bone screw fastener for axial movement of the lock washer along the prongs of the tulip head portion to secure the rod between the lock washer and the tulip head portion.
• the threaded lock nut is configured to rotatably mate with the threaded tulip head portion.
• the lock nut has opposed upper and lower surfaces. The upper surface defines at least one pawl arm.
• the pawl arm includes at least one pawl tooth for engagement with at least one of the ratchet teeth.
• a fastening device in another embodiment, includes a lock washer with opposed upper and lower surfaces and a circumferential surface therebetween.
• the circumferential surface has an array of ratchet teeth extending radially outward of the circumferential surface.
• a tapered slot is defined between the pawl arm and the threaded lock nut.
• the pawl arm includes a tapered inner surface such that the tapered slot is smaller proximate the at least one pawl tooth.
• the fastening device can also include a tool for tightening and removing the fastener.
• the tool may include at least one projection on a distal working portion.
• the projection can include a recessed extension configured to engage the tapered slot defined between the pawl arm and the threaded lock nut.
• the projection can correspond to an axially extending recessed portion defined in the threaded lock nut between the lower surface of the threaded lock nut and the pawl arm.
• the recessed extension can correspond to the tapered slot so that during tightening the recessed extension is in the larger portion of the tapered slot and during removal the recessed extension rotates counter-clockwise into the smaller portion of the tapered slot proximate the pawl tooth to splay the pawl arm radially outward.
• FIG. 1 is an exploded perspective view of a fastening device constructed in accordance with the subject technology, showing a fastener, a lock washer, a threaded lock nut and a tool.
• FIG. 2 is a perspective view of the threaded lock nut of Fig. 1, showing an upper surface of the threaded lock nut having opposing pawl arms.
• Fig. 3A is a side perspective view of the tool of Fig. 1, showing tapered ramps defined in outward extending flanges.
• Fig. 3B is a side cross- sectional view of the tool of Fig. 1, showing inner and outer diameter tiers.
• FIG. 4 is a side perspective view of another embodiment of a threaded lock nut, showing the threaded lock nut having a pair of axially extending recessed portions defined between upper and lower surfaces of the threaded lock nut.
• FIG. 5 is a perspective view of another embodiment of a tool constructed in accordance with the subject technology, showing tapered ramps defined in slots.
• Fig. 6 is a side perspective view of another embodiment of a lock washer constructed in accordance with the subject technology, showing a portion of the lower surface of the lock washer without ratchet teeth.
• Fig. 7 is an exploded perspective view of another embodiment of a fastening device constructed in accordance with the subject technology, showing a fastener, a lock washer, a threaded lock nut and a tool.
• Fig. 8 is a top view of the threaded lock nut of Fig. 6, showing an upper surface of the threaded lock nut having opposing pawl arms and tapered slots.
• Fig. 9 is a side perspective view of the tool of Fig. 1, showing a pair of projections and recessed extensions.
• Fig. 10 is a partially exploded perspective view of a fixation system for coupling a rod to bone constructed in accordance with the subject technology, showing a fastener, a rod, a lock washer, and a threaded lock nut.
• Fig. 11 is a perspective view of the lock washer of Fig. 9, showing an axial aperture with a bar defined therein, and a lower surface of the lock washer having ratchet teeth.
• FIG. 12 is a partially exploded perspective view of another embodiment of a fixation system for coupling a rod to bone constructed in accordance with the subject technology, showing a fastener, a rod, a lock washer, and a threaded lock nut.
• Fig. 13 is a perspective view of the lock washer of Fig. 11, showing an pair of discrete apertures with a bar defined therebetween, and a circumferential surface of the lock washer having ratchet teeth.
• threaded fasteners are used to fixedly connect two or more pieces in a variety of applications such as, without limitation, with surgical implants, industrial applications, aerospace applications and building applications.
• the disclosed fastening devices and systems facilitate quick and easy installation and/or removal with low torque requirements while providing a reliably vibration resistant secured tightness.
• a fastening device constructed in accordance with a preferred embodiment of the subject invention is designated generally by reference numeral 100.
• Fastening device 100 includes a fastener 102 with a head portion 104 and an elongated threaded body portion 106 extending axially from head portion 104, a lock washer 108, and a threaded lock nut 110 for rotatably mating with threaded body portion 106.
• Lock washer 108 has a lower surface 112 with a plurality of ratchet teeth 114 that entirely cover lower surface 112 of lock washer 108.
• Lock washer 108 is configured to couple to threaded body portion 106 for axial movement.
• Lock washer 108 has an axial aperture 116 with a pair of opposing flat inner surfaces 118 corresponding to the pair of opposing longitudinally extending flat sections 130 of threaded body portion 106.
• Flat sections 130 mate with flat inner surfaces 118 of lock washer 108 to rotationally fix lock washer 108 when elongated threaded body portion 106 is inserted in axial aperture 116. Lock washer 108 is permitted to move axially along threaded body portion 106.
• head portion 104 of fastener 102 can take any conventional form known in the art including, for example, a hexagonal head or a tulip head, as will be described below.
• threaded lock nut 110 has an upper surface 120 that defines a pair of opposing pawl arms 122.
• Each pawl arm 122 includes a flange 126 extending radially outward from pawl arm 122 and respective pawl teeth 124 for engagement with at least one of ratchet teeth 114.
• a flange 126 extending radially outward from pawl arm 122 and respective pawl teeth 124 for engagement with at least one of ratchet teeth 114.
• Threaded lock nut 110 includes an axial aperture 123 with threads 125 defined in the circumference of aperture 123 for mating with the threads of threaded body portion 106 for axial movement along threaded body portion 106 by rotating about threaded body portion 106.
• Threaded lock nut 110 includes a pair of axially extending recessed portions 128. Each recessed portion 128 is defined between a lower surface 121 of threaded lock nut 110 and a respective pawl arm 122.
• fastening device 100 includes a tool 140 for tightening and removing fastener 102.
• a distal working portion 142 of tool 140 includes opposing inner diameter tiers 146 and opposing outer diameter tiers 148.
• a proximal end 161 includes a socket 163 adapted to mount to a ratchet.
• Inner diameter tiers 146 of tool 140 each correspond to respective axially extending recessed portions 128 of threaded lock nut 110 for tightening threaded lock nut 110 during clockwise rotation of tool 140.
• inner diameter tiers 146 of distal working portion 142 of tool 140 are positioned within their respective axially extending recessed portion 128 of lock nut 110 with outer diameter tiers 148 disposed radially outward of lock nut 110, and tool 140 is rotated clockwise.
• a respective neck surface 147 of each inner diameter tier 146 contacts a respective shoulder surface 149 of lock nut 110, forcing clockwise rotation of lock nut 110 about threaded body portion 106 and axial movement toward head portion 104 to tighten fastener 102 in position.
• outer diameter tiers 148 each include a circumferentially extending flange 145 with respective tapered ramps 144 for applying a removal force to respective upper surfaces 125 of radially outward extending flanges 126 of pawl arms 122.
• inner diameter tiers 146 are again positioned within their respective axially extending recessed portions 128 with outer diameter tiers 148 disposed radially outward of lock nut 110, and tool 140 is rotated counter-clockwise.
• each tapered ramp 144 contacts a respective upper surface 125 of each flange 126 lifting each pawl arm 122 away from ratchet teeth 114 of lock washer 108 and disengaging pawl teeth 124 from ratchet teeth 114.
• the continued counter-clockwise rotation causes a respective second neck surface 151 of each inner diameter tier 146 to contact a respective second shoulder surface 153 of lock nut 110, forcing counter-clockwise rotation of lock nut 110 about threaded body portion 106 and axial movement away from head portion 104 to remove lock nut 110.
• Lock nut 210 is similar to lock nut 110, except that axially extending recessed portions 228 are defined between upper and lower surfaces 220 and 221, respectively, of threaded lock nut 210, instead of between lower surface 221 and pawl arm 222. It is contemplated that lock nut 210 can be used in conjunction with lock washer 108 and fastener 102, similar to lock nut 110, described above, but an alternative embodiment of a tool, e.g. tool 240, described below, can be used for tightening and removal.
• a tool e.g. tool 240
• Tool 240 is shown. Tool 240 is similar to tool 140, except that tapered ramps 244 are defined in slots 242 defined in outer diameter tiers 248. While slots 242 are shown as being cut entirely through outer diameter tier 248, it is contemplated that slots 242 could be partially cut through outer diameter tier 248. For example, slots 242 could be partially cut through from the inner diameter surface side of outer diameter tier 248. Each slot 242 includes a respective slot opening 243 that corresponds to a respective flange 226 of each pawl arm 222. Tool 240 includes opposing inner diameter tiers 246 that correspond to respective axially extending recessed portions 228 of lock nut 210.
• inner diameter tiers 246 of tool 240 are each positioned within their respective axially extending recessed portion 228 of lock nut 210 with outer diameter tiers 248 disposed radially outward of lock nut 210 and with each flange 226 received in a respective slot opening 243, and tool 240 is rotated clockwise.
• a respective neck surface 247 of each inner diameter tier 246 contacts a respective shoulder surface 249 of lock nut 210, forcing clockwise rotation of lock nut 210 about threaded body portion 106 and axial movement toward head portion 104 to tighten fastener 102 in position.
• inner diameter tiers 246 are again positioned within their respective axially extending recessed portions 228 with outer diameter tiers 248 disposed radially outward of lock nut 210 and with flange 226 received in slot opening 243, and tool 240 is rotated counter-clockwise.
• each flange 226 is free to rotate into its respective slot 242 and travel along tapered ramps 244.
• Tapered ramps 244 contact respective upper surfaces 225 of flanges 226 lifting each pawl arm 222 away from ratchet teeth 114 of lock washer 108 and disengaging pawl teeth 224 from ratchet teeth 114.
• Lock washer 308 is similar to lock washer 108 except that a recessed portion 313 of lower surface 312 of lock washer 308 does not include ratchet teeth 314.
• Lock washer 308 also includes a raised boss portion 315 defined radially between an aperture 316 and recessed portion 313 without ratchet teeth 314. It is contemplated that raised boss portion 315 can extend radially outward to abut ratchet teeth 314, or can be removed all together such that the surface is flush with recessed portion 313. It is contemplated that by not having teeth 314 extend across the entire surface of the lock washer 308, most of the clamping force is applied on raised boss portion 315 as opposed to teeth 314. This tends to allow for a greater clamping force to be applied to washer 308, as the potential for the clamping force to deform teeth 314 is reduced. Those skilled in the art will readily appreciate that recessed portion 313 tends to ease
• a fastening device 400 includes a fastener 402 with a head portion 404 and an elongated threaded body portion 406 extending axially from head portion 404, a lock washer 408, and a threaded lock nut 410 for rotatably mating with threaded body portion 406.
• Lock washer 408 has opposed upper 413 and lower surfaces 412 and a
• Circumferential surface 427 therebetween.
• Circumferential surface 427 has an array of ratchet teeth 414 extending radially outward of circumferential surface 427.
• Lock washer 408 has an axial aperture 416 with a pair of opposing flat inner surfaces 418 corresponding to the pair of opposing longitudinally extending flat sections 430 of threaded body portion 430, similar to flat inner surfaces 118 and corresponding flat sections 130, as described above.
• threaded lock nut 410 has an upper surface 420 that defines a pair of opposing pawl arms 422.
• Each pawl arm 422 includes a respective pair of pawl teeth 424 for engagement with at least one of ratchet teeth 414.
• Each pair of pawl teeth 424 extends radially inward from its respective pawl arm 422.
• Threaded lock nut 410 includes an axial aperture 423 with threads 425 defined in the circumference of aperture 423 for mating with the threads of threaded body portion 406, similar to aperture 123 and threads 125 described above.
• Threaded lock nut 410 includes axially extending recessed portions 428. Each recessed portion 428 is defined between a lower surface 421 of threaded lock nut 410 and a pawl arm 422.
• a tapered slot 411 is defined between each pawl arm 422 and threaded lock nut 410.
• Each pawl arm 422 includes a tapered inner surface 426 effectively causing the taper of tapered slot 411.
• the tapered slot 411 is smaller proximate pawl teeth 424.
• fastening device 400 includes a tool 440 for tightening and removing fastener 402.
• Tool 440 includes a pair of projections 446 on a distal working portion 442.
• Each projection 446 includes a recessed extension 448 configured to engage a respective tapered slot 411.
• Each projection 446 corresponds to a respective axially extending recessed portion 428 of threaded lock nut.
• projections 446 of tool are inserted into their respective axially extending recessed portions 428 and recessed extensions 448 extend into respective larger portions of each respective tapered slot 411.
• Tool 440 is then rotated clockwise.
• neck surfaces 447 of tool 440 each abut respective shoulder surfaces 449 of locking nut 410, forcing clockwise rotation of lock nut 410 about threaded body portion 406 and axial movement toward head portion 404 to tighten fastener 402 in position.
• a fixation system 600 for coupling a rod 605 to bone for example a spinal pedicle screw rod system, includes an elongated bone screw fastener 602 with a threaded tulip head portion 604 defining a transverse channel 607 and opposing prongs 603, and an elongated threaded body portion 606 depending from tulip head portion 604.
• Fixation system 600 also includes a lock washer 608 and a threaded lock nut 610. Threaded lock nut 610 is substantially similar to lock nut 110 except that threaded lock nut 610 is configured to rotatably mate with tulip head portion 604, instead of threaded body portion 606.
• lock washer 608 is similar to lock washer 108 except that lock washer 608 includes a bar 611 defined within an axial aperture 616 and lock washer 608 is configured for axial movement along tulip head portion 604, instead of a threaded body portion. Bar 611 extends between opposing sides of axial aperture 616 to create two discrete axial apertures 615. Each discrete axial aperture 615 includes a pair of opposing flat inner surfaces 618 corresponding to a pair of opposing longitudinally extending flat sections 630 of each prong 603.
• Flat sections 630 of each prong 603 are configured to mate with respective flat inner surfaces 618 of each discrete axial aperture 615 to rotationally fix lock washer 608 when prongs 603 of tulip head portion 604 are inserted in their respective discrete axial apertures 615, while allowing axial movement of lock washer 608 along the prongs 603 of tulip head portion 604 to secure rod 605 within the transverse channel 607 between lock washer 608 and tulip head portion 604.
• lock washer 608 is inserted over prongs 603 of tulip head portion 604. Bar 611 of lock washer 608 moves axially down transverse channel 607 and rests against rod 605.
• lock nut 610 and lock washer 608 are substantially similar to lock nut 110 and lock washer 108, a tool, e.g. tool 140 and/or tool 240, can be used to tighten rod 605 to the fastener 602 or remove rod 605 from fastener by either rotating lock nut 610 clockwise or counterclockwise.
• Traditional spinal pedicle screw rod systems tend to require a significant amount of torque to be applied, in order to lock a rod to a fastener, e.g. a pedicle screw, or to remove the rod from the fastener.
• embodiments of the present invention reduce the amount of torque required as compared with traditional spinal pedicle screw rod systems.
• a fixation system 700 for coupling a rod 705 to bone includes an elongated bone screw fastener 702 and rod 705, similar to bone screw fastener 602 and rod 605.
• Fixation system 700 also includes a lock washer 708 and a threaded lock nut 710.
• Threaded lock nut 710 is substantially similar to lock nut 410 except that threaded lock nut 710 is configured to rotatably mate with tulip head portion 704, instead of threaded body portion 706.
• lock washer 708 is similar to lock washer 408 except that lock washer 708 includes a pair of discrete axial apertures 715 and includes a bar 711 defined therebetween, and is configured for axial movement along tulip head portion 704, instead of a threaded body portion.
• Each discrete axial aperture 715 is configured to receive a respective prong 703 of tulip head portion 704 for axial movement of lock washer 708 along the prongs 703 to secure rod 705 between lock washer 708 and tulip head portion 704.
• ratchet teeth 714 extend from a circumferential surface 723 radially outward of circumferential surface 723.
• lock nut 710 and lock washer 708 are substantially similar to lock nut 410 and lock washer 408, a tool, e.g. tool 440, can be used to tighten rod 705 to the fastener 702 or remove rod 705 from fastener by either rotating lock nut 710 clockwise or counter-clockwise.
• fastening device technology is also well suited for medical applications such as attaching pedicle screws to spinal rods, attaching spinal plates and fracture plates, fixing artificial joints, like hips and knees, orthopedic and maxillofacial external fixator systems, and the like.
• fastening device technology described herein can withstand high temperature applications, for example, they can withstand temperatures as high as the material they are fabricated from can tolerate, and are easily applied, removed and reused.
• tightening of a nut e.g.
• locking nut 110, 210, 410, 610 or 710, on a fastener can be blind.
• a fastener e.g. fastener 102, 402, 602 or 702
• head portions e.g. head portions 104, 404, 604 and 704
• flats e.g. flats 130, 430, 630 or 730 on body 106 can be held or otherwise fixed during tightening.

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• 2014
  • 2014-08-14 EP EP14836937.4A patent/EP3033534A4/de not_active Withdrawn
  • 2014-08-14 WO PCT/US2014/051006 patent/WO2015023815A1/en active Application Filing
  • 2014-08-14 CA CA2921383A patent/CA2921383A1/en not_active Abandoned

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