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
  • F16B39/02—Locking of screws, bolts or nuts in which the locking takes place after screwing down
  • F16B39/20—Locking of screws, bolts or nuts in which the locking takes place after screwing down by means of steel wire or the like

Definitions

• the present invention relates to locking threaded fasteners, and more particularly to lock nuts that include a spring coil or band as a locking element.
• Lock nuts can include a spring coil or band as a locking element.
• the locking element includes one end bent radially outwardly and anchored with respect to the nut, for example, with the bent end fitted within a slot in the nut.
• the nut Under loosening torque, the nut creates a tension load on the locking element, which causes the element to tighten its grip to prevent unintended relative rotation (i.e. loosening).
• the opposite force, compression is created on the locking element during tightening (i.e. installation), which causes the locking element to loosen its grip so that there is relatively low installation torque.
• This locking system typically requires special tools or other means to enable removal of the nut.
• a number of lock nuts do not require special tools, for example, as disclosed in U.S. Patent 8,021,093 issued September 20, 2011 to Campau; U.S. Application 12/880,580 filed September 13, 2010 by Campau; and U.S. Application 13/113,357 filed May 23, 2011 by Campau.
• the lock nut disclosed in the '357 application includes a locking element that slips at a controlled removal torque.
• the disclosed lock nut provides improved structure and function over previous lock nuts.
• the new lock nut maintains the simplicity of the previous lock nuts, while improving performance. Consequently, the new lock nut provides an improved balance of simplicity, cost, and performance.
• the lock nut includes a nut body, a locking element, and a retainer.
• the locking element is (a) circumferentially surrounded without interruption by the nut body and (b) at least partially axially covered by a retainer.
• the locknut includes first and second recesses. A first tang on the lock spring is located within the first recess, and second tang on the lock spring is located within the second recess.
• the locking element and the recesses are dimensioned so that the second tang comes into contact with a wall of the second recess when a predetermined amount of removal torque is applied to the lock nut. This contact limits the amount of tension applied to the locking element, so that (1) the removal torque can be controlled and (2) the locking element is not damaged.
• the locking element includes a coil portion and two tangs extending from the coil portion.
• the locking element is located within and circumferentially surrounded without interruption by the nut body.
• the first tang is fixed with respect to the nut body to prevent angular movement of the first tang with respect to the body.
• the retainer at least partially axially covers the locking element to protect the locking element from dirt, grease, and other contaminants.
• the retainer cover may have a diameter corresponding to the external diameter of the threaded member on which the lock nut is mounted so as to seal the cover against the threaded member.
• the retainer portion may be elastic to enhance the seal against the threaded member.
• FIG. 1 is a perspective view of a first embodiment of the locking fastener.
• Fig. 2 is a top view of the first embodiment with the retainer cover removed and with a removal torque applied to the locking fastener.
• Fig. 3 is a perspective view of the first embodiment with the retainer cover and the locking element removed.
• Fig. 4 is a top view of the locking element of the first embodiment.
• Fig. 5 is an exploded view of the first embodiment aligned with a threaded member.
• FIG. 6 is a perspective view of a second embodiment of the locking fastener.
• FIG. 7 is a top view of the second embodiment with the retainer cover removed and without removal torque applied to the locking fastener.
• FIG. 8 is a perspective view of the second embodiment with the retainer cover and the locking element removed.
• FIG. 9 is a top view of the second embodiment with the retainer cover and the locking element removed.
• Fig. 10 is an exploded view of the second embodiment aligned with a threaded member.
• FIG. 11 is a perspective view of a third embodiment of the locking fastener.
• FIG. 1-5 A locking threaded fastener constructed in accordance with a first embodiment of the invention is illustrated in Figs. 1-5 and generally designated 40. Though shown in Figs. 1-5 as a retaining nut or a lock nut, the concepts of the present invention can be incorporated into a variety of fasteners as will be recognized by those skilled in the art.
• the threaded fastener 40 includes a body 42 and a locking element, spring, or band 44.
• the body 42 includes a hex-shaped outer portion 46 configured to be engaged and driven by a conventional driving tool (not shown).
• the hex- shaped portion 46 includes a plurality of corners 48 and a plurality of flats 50 extending therebetween.
• the body 42 may be square, otherwise polygonal, or any other shape.
• the body 42 may also be shaped to be engaged by any conventional driving tool, now known or later developed.
• the body 42 defines a bore 52, which is at least partially threaded along its length. As perhaps best shown in Fig. 3, the bore 52 includes a first portion 54 that is threaded and a second portion, pocket, recess, or retainer wall 56 that is unthreaded. The diameter of the unthreaded portion 56 is greater than the diameter of the threaded portion 54. A lower lip 60 separates the first and second portions 54, 56.
• the body 42 further defines a first or anchor recess 62 and a second or release recess 64 communicating with the bore 52. Alternatively, one or both of the recesses 62,64 may be defined by the retainer portion 90.
• the first and second recesses 62, 64 are defined in an interior of the body 42 so that the first and second recesses 62, 64 are isolated from the environment surrounding the fastener body 42.
• the locking band 44 includes a coil or continuously curved portion 70 having a circular cross-section extending between a first tang or end portion 72 and a second tang or end portion 74. Though illustrated with a circular cross-section, other cross-sectional shapes are contemplated including square, rectangular, oval, triangular, and any other suitable shape.
• the first and second tangs or end portions 72, 74 are straight, but other shapes, including smooth curves and angles, are also contemplated. Perhaps as best shown in Fig. 4, both tangs 72, 74 extend tangentially outward from the curved portion 70. Also as shown in Fig. 4, the locking band 44 may include a single turn, with the first tang 72 overlapping the second tang 74. The locking band 44 may alternatively include less than a single turn, or two or more helical turns so that adjacent turns are substantially in contact with each other. If the locking band 44 includes less than a single turn, the locking band 44 may extend entirely within a single plane oriented perpendicular to the bore 52, or may extend helically. As shown in Fig. 4, the locking band 44 may be symmetrical to simplify manufacturing.
• the diameter of the circular cross-section of the locking band 44 generally corresponds to the pitch of the externally threaded member 45 so that the locking band 44 fits within the threads of the threaded member 45.
• the dimension of the surface engaging the threads of the threaded member 45 may be less than, generally the same as, or greater than the pitch of the threaded member.
• the tangentially-extending tang 72 is received and constrained within the first recess 62 in the fastener body 42.
• the first recess 62 has a side wall 80 that constrains the angular movement of first tang 72 relative to the body 42.
• a side surface of first tang 72 may contact side wall 80.
• the first recess 62 may include a notch 66 to allow a side surface of first tang 72 to fit flush against side wall 80.
• the first recess 62 may have an end wall 82 instead of or in addition to side wall 80 that engages an end surface of the first tang 72 during rotation of the body 42.
• the end wall 82 may be substantially perpendicular to the side wall 80 as illustrated, or may be at an angle relative to the side wall 80.
• the first recess 62 may be configured to engage a corner or any other suitable surface of the first tang 72 during rotation of the fastener body 42.
• the first recess side wall 80 is oriented generally tangentially to the bore 52 so as to receive the tangential tang 72. Consequently, the tang 72 is angularly fixed with respect to the body 42.
• the second tang 74 is normally free to rotate angularly relative to the body 42 within the second recess 64. However, as described below and as shown in Fig. 2, the second tang 74 may contact the second recess wall 84 during removal or counterclockwise rotation of the body 42, which limits the angular movement of the second tang 74 relative to the body 42.
• the body 42 may instead define a combination of recesses and/or surfaces to receive each of the tangs 72, 74.
• the locking band 44 allows desired loosening of the threaded fastener 40 if sufficient torque is applied to the body 42.
• the first tang 72 which is angularly constrained by the first recess 62, may elastically deflect which in turn allows the body 42 to rotate through a small angle relative to the locking band 44.
• this rotation forces the second tang 74, which extends tangentially from the coil portion 70, into contact with the second recess wall 84 in the nut body 42.
• the contact may be between an end surface of second tang 74 and a corner of the second recess 64, or may be between any two surfaces that would restrain the angular movement of the second tang 74 relative to the body 42.
• This contact reduces or potentially eliminates any further increase in stress on the locking element 44 as removal torque is applied to rotate the fastener 40 off the externally threaded member 45. Consequently, there is little or no damage to either the external thread or the locking element 44.
• the second recess 64 may be designed to control the removal torque to a predetermined or preselected level by allowing a predefined degree of movement of second tang 74.
• the diameter of the locking band 44 may be selected so that a single locking band 44 may be used with all external thread classes within a particular thread size. It has been found that a single locking band 44 may "self-adjust" to accommodate various thread classes at least partially because the locking band 44 can slide along the first recess side wall 80. Alternatively, different locking bands 44 may be designed for use with different thread sizes, or different external thread classes within a particular thread size. Further, the cross- sectional shape, material strength, and elasticity of locking band 44 may be selected based on the desired application.
• the body 42 and the locking band 44 may be manufactured from any suitable materials, including metals and composites. Additionally, because of the reduced stress in the locking band 44 during use of the threaded fastener 40, locking band 44 may be manufactured from relatively low-cost materials such as round steel wire.
• the threaded fastener 40 includes a retainer portion 90.
• the retainer portion 90 may be an integral portion of the fastener body 42, or the retainer portion 90 may be separate from, extending from, the fastener body 42. As shown in Figs. 1 and 3, the retainer portion 90 at least partially houses the locking band 44 and isolates the locking band 44.
• the retainer portion 90 may include a first lip 92 for supporting the second tang 74 and a retainer wall 56 for engaging the coil 70.
• a second lip 94 may be defined by the retainer wall 56 and adapted to support and engage a retainer cover 96.
• a retainer flange 98 may further support and engage the retainer cover 96. As illustrated, the retainer flange 98 may extend substantially parallel to the bore 52.
• the retainer flange 98 may optionally include an outer flange lip to provide a snap-fit retention of the retainer cover 96. Further optionally, the retainer cover 96 may be formed over the flange 98. As illustrated, the retainer cover 96 may conceal and protect the locking band 44 from the environment surrounding the fastener 40. The retainer cover 96 may be eliminated if the retainer flange 98 is made sufficiently tall to provide a desired level of protection for the locking band 44.
• the retainer cover 96 may be any variety of suitable shapes, including a cylindrical washer-like shape as illustrated.
• the retainer cover 96 may be suitably sized for the application.
• the inner diameter of the retainer cover 96 may be sized slightly larger than the threaded member 45 to allow for complete clearance of the threaded member 45 through the retainer cover 96.
• the inner diameter of the retainer cover 96 may be sized to interact tightly with the threads of the threaded member 45.
• the inner diameter of the retainer cover 96 may be sized smaller than the threaded member 45.
• the retainer cover 96 may be made of any suitable material, including metals, composites and flexible materials.
• the retainer cover 96 may be made of a flexible material (for example, an elastomer) to provide a seal against the threaded member 45 to prevent dirt and debris from entering the retainer portion 90.
• a flexible material for example, an elastomer
• Installation of the locking band 44 can be accomplished in a number of ways.
• the band 44 is installed by compressing it sufficiently to snap it into place in retaining portion 90.
• retainer cover 96 may be installed with a snap-fit, friction-fit, adhesive, or any other suitable securing mechanism.
• the retainer cover 96 may be formed over the retainer flange 98. Further optionally, the locking band 44 could be wound in place.
• the locking torque can be a function of a number of variables, including the initial diameter of the locking band, the material properties of the locking band, the coefficient of friction of the locking band, the number of turns of the locking band and the shape and size of the first and second recesses 62, 64.
• parameter tolerances will affect the range of locking torque for a particular configuration. Parameters for the locking band 44 can therefore be selected for each thread size and tolerance range to provide the slip torque less than the ultimate strength of the locking band 44 while still providing an acceptable locking torque range.
• the locking torque can be set to meet or to exceed relevant industry standards.
• the present locking threaded fastener 40 includes a oneway prevailing torque, which may allow installation torque to be very low when compared to standard prevailing torque threaded fasteners.
• the locking band fastener removal prevailing torque is less subject to degradation over multiple uses when compared to a typical locking fastener.
• a locking threaded fastener constructed in accordance with a second embodiment of the invention is illustrated in Figs. 6-10 and generally designated 140.
• the threaded fastener 140 is structurally and functionally similar to the previously described threaded fastener 40. Consequently, each element of the threaded fastener 140 is identified by the same designating numeral as the corresponding element in the threaded fastener 40 with the exception that the numeral begins with a 1.
• the locking band 144 in the threaded fastener 140 corresponds to the locking band 44 in the threaded fastener 40. Only the elements that differ significantly are described below.
• the threaded fastener 140 includes a first recess 162 and a second recess 164 with different sizes and shapes than the recesses 62, 64 in the first embodiment.
• the different recesses 162, 164 may result in a different removal torque for the threaded fastener 140.
• the recesses 162, 164 are configured to allow the locking band 144 to expand so that the two tangs 172, 174 are expanded past parallel with one another.
• the different contours of the second recess 164 may also result in a different interaction between the second tang 174 and the second recess wall 184 and may create a different locking torque.
• the first recess 162 may extend completely to the lower lip 160.
• the retainer flange 198 may be made shorter than in the first embodiment to provide the retainer portion 190 with a relatively lower profile.
• a locking threaded fastener constructed in accordance with a third embodiment of the invention is illustrated in Fig. 11 and generally designated 240.
• the threaded fastener 240 is structurally and functionally similar to the previously described threaded fastener 40. Consequently, each element of the threaded fastener 240 is identified by the same designating numeral as the corresponding element in the threaded fastener 40 with the exception that the numeral begins with a 2. Only the elements that differ significantly are described below.
• the threaded fastener 240 includes a cover 296 that encloses the locking element 244.
• the cover 296 includes a lip portion 220 and a cover portion 222.
• the cover portion 222 may extend outward away from the lip portion 220.
• the distance the cover portion 222 extends away from the lip portion 220 may be designed to accommodate various sizes of threaded members 245.
• the cover portion 222 may be any of a variety of shapes, including substantially cylindrical, as shown in Fig. 11.

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• Engineering & Computer Science (AREA)
• General Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Clamps And Clips (AREA)

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• 2012
  • 2012-12-21 WO PCT/US2012/071114 patent/WO2013112254A1/en active Application Filing
  • 2012-12-21 CA CA2860760A patent/CA2860760C/en not_active Expired - Fee Related
  • 2012-12-21 AU AU2012367224A patent/AU2012367224B2/en not_active Ceased
  • 2012-12-21 EP EP12821086.1A patent/EP2812587A1/de not_active Withdrawn
  • 2012-12-21 JP JP2014554722A patent/JP5745193B2/ja not_active Expired - Fee Related
  • 2012-12-21 CN CN201280068074.8A patent/CN104204561B/zh not_active Expired - Fee Related
• 2014
  • 2014-07-25 ZA ZA2014/05531A patent/ZA201405531B/en unknown

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