Anti-twist device

Abstract

The embodiments described and claimed herein relate to opening in a housing for a retractor. The opening includes structures which reduce the risk of twisting webbing passing through the opening and, thereby, interfering with the proper functionality of the retractor. The openings can include one or more guide surfaces which incorporate some combination of features which smooth out the webbing as it enters the retractor and/or urge the webbing into alignment with the retractor opening. In addition, or in the alternative, the height of the opening can be modified to closely conform to the maximum thickness of the webbing. The guide surfaces can be integrally formed with the retractor housing or can be provided by an insert piece which attaches to the housing. In one embodiment, the guide surface is disposed along an upper wall of the opening and is curvilinear and outwardly diverging. More specifically, the guide surface has slopes that vary along its length whereby the guide surface is approximately vertical near a leading edge of the guide surface and is approximately horizontal near a trailing edge of the guide surface.

1 . A device for reducing the chances that a twisted portion of a restraint strap will interfere with the operation of a retractor comprising:
 a housing, a retractor spool, and a restraint strap, the restraint strap being wound on the retractor spool and having a thickness;   the housing defining an interior space in which a retractor spool is disposed and having an opening which is adapted for passing the strap therethrough; and,   the opening having an effective height which is between approximately two and eight times the thickness of the restraint strap to allow a double stitched portion of the restraint strap to pass therethrough.   
   
   
       2 . The device of  claim 1 , wherein the effective height is between approximately two and six times the thickness of the restraint strap. 
   
   
       3 . The device of  claim 1 , wherein the housing is a retractor cover. 
   
   
       4 . The device of  claim 1 , wherein the housing is a barrier housing. 
   
   
       5 . The device of  claim 1 , wherein the opening is provided with at least one guide surface, the guide surface having at least one slope between a leading edge and a trailing edge, wherein the at least one slope causes the leading edge to diverge from an opposing sidewall. 
   
   
       6 . The device of  claim 5 , wherein the at least one slope comprises at least a first slope near the leading edge and at least a second slope near the trailing edge, wherein the guide surface is aligned approximately perpendicular to an axis of the opening near the leading edge and is aligned approximately parallel to the axis of the opening near the trailing edge. 
   
   
       7 . The device of  claim 6 , wherein the guide surface is curvilinear and includes a variable slope between the leading and trailing edges. 
   
   
       8 . The device of  claim 1 , wherein the opening includes a plurality of contoured guide surfaces, at least one of which is adapted to guide the movement of the lateral edges of the strap. 
   
   
       9 . The device of  claim 1 , wherein a guide surface for the opening is formed on a member which is attachable to the housing, the guide surface constricting a size of the opening to provide the opening with the effective height. 
   
   
       10 . The device of  claim 9 , wherein the member includes at least one locking groove whereby the member can be engaged with the opening by snapping into place. 
   
   
       11 . The device of  claim 1 , wherein the opening is generally quadrangular and includes four walls, onto one of which at least one guide surface is formed. 
   
   
       12 . A device for reducing the chances that a twisted portion of a restraint strap will interfere with the operation of a retractor comprising:
 a housing, a retractor spool, and a restraint strap, the restraint strap being wound on the retractor spool and having a thickness;   the housing defining an interior space in which a retractor spool is disposed and having an opening which is adapted for passing the strap therethrough;   the opening having at least one sidewall, with at least a portion of the sidewall having a guide surface, the guide surface being configured to guide the movement of the strap and thereby resist the passing of a twist in the strap through the opening and into the housing; and,   the guide surface having a leading edge and a trailing edge, the guide surface extending a distance into the opening whereby the trailing edge is disposed within the interior space of the housing.   
   
   
       13 . The device of  claim 12 , wherein the housing is a retractor cover. 
   
   
       14 . The device of  claim 12 , wherein the housing is a barrier housing. 
   
   
       15 . The device of  claim 12 , wherein the trailing edge of the guide surface is disposed in close proximity to the retractor spool. 
   
   
       16 . The device of  claim 12 , wherein the guide surface has at least one slope between the leading edge and the trailing edge, wherein the at least one slope causes the leading edge to diverge from an opposing sidewall. 
   
   
       17 . The device of  claim 16 , wherein the at least one slope comprises at least a first slope near the leading edge and at least a second slope near the trailing edge, wherein the guide surface is aligned approximately perpendicular to an axis of the opening near the leading edge and is aligned approximately parallel to the axis of the opening near the trailing edge. 
   
   
       18 . The device of  claim 12 , wherein the guide surface is curvilinear and includes a variable slope between the leading and trailing edges. 
   
   
       19 . The device of  claim 12 , wherein the opening includes a plurality of contoured guide surfaces, at least one of which is adapted to guide the movement of the lateral edges of the strap. 
   
   
       20 . The device of  claim 12 , wherein the guide surface for the opening is formed on a member which is attachable to the housing. 
   
   
       21 . The device of  claim 20 , wherein the member includes at least one locking groove whereby the member can be engaged with the opening by snapping into place. 
   
   
       22 . The device of  claim 12 , wherein the opening is generally quadrangular and includes four walls, onto at least one of which the guide surface is formed. 
   
   
       23 . A device for reducing the chances that a twisted portion of a restraint strap will interfere with the operation of a retractor comprising:
 a housing, a retractor spool, and a restraint strap, the restraint strap being wound on the retractor spool and having a thickness;   the housing defining an interior space in which a retractor spool is disposed and having an opening which is adapted for passing the strap therethrough;   the opening having an effective height which is between approximately two and eight times the thickness of the restraint strap to allow a double stitched portion of the restraint strap to pass therethrough;   the opening having at least one sidewall, with at least a portion of the sidewall having a guide surface, the guide surface being configured to guide the movement of the strap and thereby resist the passing of a twist in the strap through the opening and into the housing; and,   the guide surface having a leading edge and a trailing edge, the guide surface extending a distance into the opening whereby the trailing edge is disposed within the interior space of the housing.   
   
   
       24 . The device of  claim 23 , wherein the effective height is between approximately two and six times the thickness of the restraint strap. 
   
   
       25 . The device of  claim 23 , wherein the housing is a retractor cover. 
   
   
       26 . The device of  claim 23 , wherein the housing is a barrier housing. 
   
   
       27 . The device of  claim 23 , wherein the trailing edge of the guide surface is disposed in close proximity to the retractor spool. 
   
   
       28 . The device of  claim 23 , wherein the guide surface has at least one slope between a leading edge and a trailing edge, wherein the at least one slope causes the leading edge to diverge from an opposing sidewall. 
   
   
       29 . The device of  claim 28 , wherein the at least one slope comprises at least a first slope near the leading edge and at least a second slope near the trailing edge, wherein the guide surface is aligned approximately perpendicular to an axis of the opening near the leading edge and is aligned approximately parallel to the axis of the opening near the trailing edge. 
   
   
       30 . The device of  claim 29 , wherein the guide surface is curvilinear and includes a variable slope between the leading and trailing edges. 
   
   
       31 . The device of  claim 30 , wherein the opening includes a plurality of contoured guide surfaces, at least one of which is adapted to guide the movement of the lateral edges of the strap. 
   
   
       32 . The device of  claim 30 , wherein a guide surface for the opening is formed on a member which is attachable to the housing, the guide surface constricting a size of the opening to provide the opening with the effective height. 
   
   
       33 . The device of  claim 32 , wherein the member includes at least one locking groove whereby the member can be engaged with the opening by snapping into place.