Abstract:
A release mechanism of efficient construction and operation is provided to hold profile restraining air bag tethers in a shortened operative condition under a first set of predetermined conditions and to extend such tethers under a second set of predetermined conditions. The extension of the restraining tethers may be carried out in conjunction with the delivery of an increased volume of inflating gas to the air bag cushion utilizing a gas emitting inflator in conjunction with a dynamic variable inflation device to effect delivery of a proper volume of inflation gas while releasing the tethers from a restrained length condition.

Description:
CROSS-REFERENCE TO RELATED APPLICATION  
       [0001]    This application claims priority from U.S. Provisional Application 60/271,833 to Dunkle et al. having a filing date of Feb. 27, 2001. 
     
    
     
       TECHNICAL FIELD  
         [0002]    This invention relates generally to an air bag assembly, and more particularly to an air bag assembly capable of variable expansion by selective retention or extension-inducing release of restraining tether elements.  
         BACKGROUND OF THE INVENTION  
         [0003]    It is well known to provide an air bag assembly including an inflatable air bag cushion for protecting the occupants of a transportation vehicle. In an automotive vehicle such air bag assemblies are typically located within the hub of the steering wheel and in a recess in the instrument panel for protection of the vehicle occupants seated in opposing relation to such assemblies. Additional air bag assemblies may be located within the seats and/or door panels for protection of the occupants during a side-impact event.  
           [0004]    Air bag assemblies typically include an inflatable cushion in fluid communication with a gas emitting inflator. Upon sensing certain predetermined vehicle conditions, such as a certain level of vehicle deceleration, the inflator discharges a fixed amount of inflator gas thereby forcing the air bag into a deployed position. The inflator gas occupies the available volume within the air bag cushion thereby forcing the air bag cushion to expand outwardly to the extent permitted by its construction. As the occupant comes into contact with the expanded air bag, the inflator gas is forced out of the air bag thereby dissipating the kinetic energy of the occupant.  
           [0005]    Absent restraint, an inflated body tends to assume a generally spherical profile. In order to provide control over the inflated shape of the air bag cushion, it is known to utilize tethering elements in the form of straps or webs extending between surfaces of the air bag cushion to thereby hold the surfaces in fixed orientation relative to one another upon inflation. The selection and length of such tethering elements can thus be used to establish a desired inflated profile. However, once the tethering elements are attached in fixed relation to the surface of the air bag cushion, the inflated geometry of the cushion is likewise fixed and is not subject to adjustment.  
           [0006]    It has been recognized that the preferred inflated profile of the air bag cushion may vary depending upon the severity of the activating impact event and/or upon the size and position of the occupant to be protected. Thus, the ability to effectively control the inflation characteristics of the air bag cushion is potentially desirable. In order to provide a degree of control over the inflated profile of the air bag cushion it is known to use an inflator that has varied levels or stages of inflator gas output in response to the sensing of different vehicle occupant conditions. Thus, it is generally known in the prior art to utilize so-called “dual-stage” inflators that discharge predetermined amounts of gas at one or two levels. However, these “dual-stage” inflators are more complex than typical inflators and have the limitation of typically providing only discrete levels of gas output. Moreover, the use of such “dual-stage” inflators provides control over only the amount of inflator gas which is discharged and does not provide control over the expanded geometry of the inflated air bag cushion. That is, due to the compressible nature of the inflation gas, so long as the air bag has a fixed volumetric capacity, the inflator gas will tend to fill that capacity and the expanded configuration of the air bag will be generally the same although the pressure may vary.  
           [0007]    In order to provide an additional level of control over the air bag performance it has been suggested to utilize air bag cushions which incorporate sewn or woven in seams within the air bag to control the expanded geometry of the inflated air bag. Such seams separate upon the introduction of pressures exceeding a certain level thereby freeing the air bag cushion from the restraint imposed by the seams at lower pressures. In order for such break-away seams to provide controlled expansion, the introduction of such seams must be carried out with substantial precision such that seam separation will occur in a highly reproducible and predictable manner. In some instances, such requisite precision and reproducibility may be difficult to achieve. Moreover, even when such break-away seams are utilized, the expansion which occurs may be in all directions. In some applications it is believed that preferential expansion in the depth of the air bag (i.e. towards the occupant to be protected) may be desirable.  
           [0008]    In order to address the desire to provide enhanced control over the final inflated profile of the air bag, it has been proposed to utilize release mechanisms to hold tether straps in place under normal conditions and to release the straps in situations where an extended profile is desired. Several of such release mechanisms are illustrated and described in U.S. Pat. No. 5,887,894 to Castagner et al. the contents of which are incorporated by reference as if fully set forth herein.  
         SUMMARY OF THE INVENTION  
         [0009]    This invention provides advantages and alternatives over the prior art by providing a release mechanism of efficient construction and operation to hold restraining air bag tethers in place under a first set of predetermined conditions and to extend such tethers under a second set of predetermined conditions. The extension of the restraining tethers may be carried out in conjunction with the delivery of an increased volume of inflating gas to the air bag cushion. The air bag assembly may utilize a single stage inflator in conjunction with a variable inflation device to effect delivery of a proper volume of inflation gas. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0010]    The present invention will now be described by way of example only, with reference to the accompanying drawings which constitute a part of the specification herein and in which:  
         [0011]    [0011]FIG. 1 is a cut-away view of a vehicle interior showing an air bag cushion in a stored undeployed state in opposing relation to a vehicle occupant;  
         [0012]    [0012]FIG. 2A is a view similar to FIG. 1 illustrating an air bag cushion in a deployed state restrained by an internal tether arrangement;  
         [0013]    [0013]FIG. 2B is a view similar to FIG. 2A wherein the tether arrangement is released to a second restrained state to permit enhanced expansion of the air bag cushion towards a vehicle occupant;  
         [0014]    [0014]FIG. 3A is an exploded perspective view of a variable inflation device and cooperative tether restraint assembly;  
         [0015]    [0015]FIG. 3B is a cut-away side view of an air bag assembly incorporating the variable inflation device and cooperative tether restraint assembly illustrated in FIG. 3A;  
         [0016]    [0016]FIG. 4A is an exploded perspective view of a variable inflation device and cooperative tether restraint assembly;  
         [0017]    [0017]FIG. 4B is a cut-away side view of an air bag assembly incorporating the variable inflation device and cooperative tether restraint assembly of FIG. 4A;  
         [0018]    [0018]FIG. 5A is an exploded perspective view of a variable inflation device and a cooperative tether restraint assembly;  
         [0019]    [0019]FIG. 5B is a cut-away side view of an air bag assembly incorporating the variable inflation device and cooperative tether restraint assembly illustrated in FIG. 5A;  
         [0020]    [0020]FIG. 6A is cut-away end view of an air bag module assembly incorporating a variable inflation device and a cooperating tether restraint assembly prior to activation of the variable inflation device;  
         [0021]    [0021]FIG. 6B is a view similar to FIG. 6A following activation of the variable inflation device and corresponding release of a restrained tethering element to an increased operative length;  
         [0022]    [0022]FIG. 7A is a view similar to FIG. 6A illustrating an alternative arrangement of a variable inflation device and cooperative tether restraint assembly prior to activation of the variable inflation device;  
         [0023]    [0023]FIG. 7B is a view similar to FIG. 7A following activation of the variable inflation device and corresponding release of a restrained tethering element to an increased operative length;  
         [0024]    [0024]FIG. 8A is a view similar to FIG. 6A illustrating a variable inflation device and a cooperative tether restraint assembly prior to activation of the variable inflation device;  
         [0025]    [0025]FIG. 8B is a view similar to FIG. 8A following activation of the variable inflation device and release of a restraining tether from the tether restraint assembly to an increased operative length;  
         [0026]    [0026]FIG. 9A is a view similar to FIG. 6A illustrating a variable inflation device and a cooperative tether restraint assembly prior to activation of the variable inflation device;  
         [0027]    [0027]FIG. 9B is a view taken along line  9 B- 9 B in FIG. 9A illustrating a tether holding hook arrangement;  
         [0028]    [0028]FIG. 9C is a view similar to FIG. 9B illustrating an alternative tether holding hook arrangement;  
         [0029]    [0029]FIG. 9D is a view similar to FIG. 9A following activation of the variable inflation device and release of the cooperative tether restraint assembly to an increased operative length;  
         [0030]    [0030]FIG. 10A is an elevation exploded perspective view of a variable inflation device and a cooperative tether restraint assembly incorporating a side mounted slide;  
         [0031]    [0031]FIG. 10B is a view of the side mounted slide in FIG. 10A in a tether restraining position;  
         [0032]    [0032]FIG. 10C is a view similar to FIG. 10B with the side mounted slide in the tether release position;  
         [0033]    [0033]FIG. 11A is an elevation exploded perspective view of a variable inflation device and a cooperative tether restraint assembly incorporating a side mounted slide;  
         [0034]    [0034]FIG. 11B is a view of the side mounted slide in FIG. 11A in a tether restraining position;  
         [0035]    [0035]FIG. 11C is a sectional side view taken through FIG. 11B;  
         [0036]    [0036]FIG. 11D is a view similar to FIG. 11C with the side mounted slide in the tether release position;  
         [0037]    [0037]FIG. 12A is cut-away end view of an air bag module assembly incorporating a variable inflation device and a cooperating tether restraint incorporating a rotating vent blocking element prior to activation of the variable inflation device;  
         [0038]    [0038]FIG. 12B is a view similar to FIG. 12A following activation of the variable inflation device and corresponding release of a restrained tethering element to an increased operative length;  
         [0039]    [0039]FIG. 13A is an elevation perspective view of an air bag assembly incorporating a cooperative tether release assembly and vent blocking element prior to activation;  
         [0040]    [0040]FIG. 13B is a cross sectional view taken through FIG. 13A;  
         [0041]    [0041]FIG. 13C is a view similar to FIG. 13A following activation and release of tethering elements to an increased operative length;  
         [0042]    [0042]FIG. 14A is an elevation perspective view of an air bag assembly incorporating a cooperative tether release assembly and vent blocking element prior to activation;  
         [0043]    [0043]FIG. 14B is a view similar to FIG. 14A following activation and release of tethering elements to an increased operative length;  
         [0044]    [0044]FIGS. 15A and 15B illustrate a first exemplary moveable tether retaining element for use in the air bag assembly of FIG. 14A;  
         [0045]    [0045]FIGS. 16A and 16B illustrate a second exemplary moveable tether retaining element for use in the air bag assembly of FIG. 14A;  
         [0046]    [0046]FIGS. 17A and 17B illustrate respectively third and fourth exemplary moveable tether retaining elements for use in the air bag assembly of FIG. 14A; and  
         [0047]    [0047]FIG. 18 illustrates a fifth exemplary moveable tether retaining element for use in the air bag assembly of FIG. 14A; 
     
    
       [0048]    While the invention has been illustrated and will hereinafter be described in connection with certain potentially preferred embodiments, procedures and practices, it is to be understood that in no event is the invention to be limited to such illustrated and described embodiments, procedures and practices. On the contrary, it is intended that the present invention shall extend to all alternatives and modifications as may embrace the principles of this invention within the true spirit and scope thereof.  
       DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0049]    Reference will now be made to the drawings, wherein to the extent possible, like reference numerals are utilized to designate like components throughout the various views. In FIG. 1 a vehicle  10  is shown including a seating structure  12  which supports an occupant  14  in generally opposing relation to an instrument panel  16 . An air bag assembly  18  including an air bag cushion  20  is housed within the instrument panel  16  for outward deployment towards the occupant  14  in the event of a collision.  
         [0050]    While the air bag assembly  18  and corresponding air bag cushion  20  are illustrated for descriptive purposes in relation to a vehicle passenger, it is to be understood that the present invention is in no way to be limited to a passenger side configuration. On the contrary, it is contemplated that the present invention may have applicability to air bag deployment in opposing relation to the operator (not shown) of the vehicle  10  as well as in relation to air bags deployed from other regions within the vehicle interior.  
         [0051]    It is contemplated that the vehicle  10  may include a seat position sensor  22  to detect the position of the occupant  14  relative to the air bag assembly  18 . It is further contemplated that the vehicle  10  may include additional position sensors such as an optical scanner  24  or the like to measure both the volume and position of the occupant to be protected. The vehicle  10  may also be provided with a scale  26  within the seating structure  12  so as to provide additional data regarding the load to which the inflatable air bag cushion  20  may be subjected upon impact by the occupant  14 . It is additionally contemplated that the seating structure  12  may be provided with sensing elements to measure the degree to which the seating structure is reclined. The vehicle  10  may also be provided with sensors to determine and communicate whether or not the occupant is utilizing the recommended seat belt structures  28 . The data so collected may be utilized to determine the desirable expanded profile characteristics for the air bag cushion  20  in a given situation.  
         [0052]    It is contemplated that the air bag cushion  20  has a first expanded profile which is obtained upon full extension of internal tethering elements  30  and at least a second expanded profile which is characterized by less depth than the first expanded profile. As best illustrated through simultaneous reference to FIGS. 2A and 2B, it is contemplated that one or more tethering elements  30  in the form of straps extending from locations at the interior of the air bag cushion  20  are utilized to control the inflated profile of the air bag cushion  20 . The tethering elements  30  are normally held in fixed relation between connection points  29  at the interior of the cushion and a releasable restraint assembly  36  in the vicinity of a gas generating inflator  40 . This releasable attachment may be effected by use of an integral or supplemental sliding loop structure  25  although it is contemplated that any number of other arrangements may likewise be utilized.  
         [0053]    As shown in FIG. 2A under normal operating conditions, the tethering elements  30  restrain the profile of the expanding air bag cushion  20  to a first diminished depth. By way of example only, and not limitation, it is contemplated that such a restrained profile may be of particular use in the protection of smaller stature occupants and/or occupants seated in close proximity to the instrument panel  16 . As shown in FIG. 2B, in instances where a larger profile is desired, the tethering elements  30  may be released from the restraint assembly  36  thereby yielding a permissible expanded geometry of expanded depth. In the event that the tethering elements  30  are released from the restraint assembly, it is contemplated that some degree of restraint may nonetheless be maintained by a length extending tether extension  23  such as a strap or the like operatively connected between the tethering elements and a secondary attachment location  27  which may be either on the surface of the air bag cushion or at an external location. By way of example only, and not limitation, it is contemplated that such an expanded depth may be particularly useful in the protection of larger stature occupants and/or in the protection of occupants seated a substantial distance away from the instrument panel  16 .  
         [0054]    As will be appreciated, upon the release of the tethering elements  30  from the restraint assembly  36 , the volume of the air bag is increased. According to a potentially preferred practice, the air bag assembly  18  incorporates a selectively activatable variable inflation device which causes more or less inflation gas to be delivered to the air bag cushion depending upon the desired inflation characteristics. That is, the variable inflation device will deliver a greater quantity of inflation gas to the air bag cushion  20  in instances where a deep profile such as is illustrated in FIG. 2B is desired. Conversely, in instances where a more shallow inflated profile is desired such as illustrated in FIG. 2A, a smaller quantity of inflation gas is released into the air bag cushion  20 .  
         [0055]    According to a first exemplary practice, the variable inflation device incorporates a sliding vent blocking element which may be moved from a first position to a second position so as to either open or close a vent opening within the air bag assembly  18  thereby adjusting the volume of inflation gas passing from the inflator  40  into the air bag cushion  20 . This opening or closing may be either partial or complete. By way of example only, and not limitation, one such variable inflation device is illustrated and described in U.S. Pat. No. 6,123,358 to Ryan et al. the contents of which are incorporated by reference as if fully set forth herein. It is contemplated that the action of the vent blocking element will simultaneously increase the volume of the inflation gas entering the air bag cushion and disengage the tether elements  30  from the restraint assembly  36  so as to extend the operative length of the tether element such that an enhanced volume of inflation gas is selectively delivered to the air bag cushion  20  in conjunction with the operative extension of the tether elements  30 .  
         [0056]    In FIGS. 3A and 3B there is illustrated a first arrangement for a cooperative tether extension assembly and variable inflation device wherein elements corresponding to those previously described are designated by like reference numerals in a  100  series. As illustrated, in this arrangement a tethering element  130  is passed through the interior of a loop element  132  of a generally pliable material such as fabric or the like of high tensile strength. The configuration of the loop element  132  and the tethering element  130  is thereafter maintained by attaching surfaces of the folded tethering element  130  to one another by stitching  134  or other attachment techniques such as adhesives and cooperating hook and loop elements as will be well known to those of skill in the art at a location remote from the loop element  132 . While only a single tethering element  130  is illustrated, it is to be appreciated that multiple tethering elements may be incorporated if desired. A portion of the tethering element  130  extending away from the loop element  132  forms a length extending tether extension  123  which may be anchored in fixed or releasable relation to an anchor point (not shown) such as a stitched attachment to the interior or exterior surface of the air bag cushion. This length extending tether extension  123  acts as a mooring line to provide a secondary tethering restraint when the loop element  132  is released in the manner as will now be described.  
         [0057]    As illustrated, the cooperative assembly includes an end cap  133  which preferably has a configuration generally corresponding to the cross-sectional geometry of an inflator housing  142  supporting the gas generating inflator  140  (FIG. 3B). The end cap  133  preferably includes an aperture  135  extending therethrough. The aperture  135  is sized to accept a squib-containing head portion  136  of a dynamic variable inflation device  137 . A head cap  138  covers the head portion  136  following assembly. As shown, the variable inflation device  137  includes a slideable vent blocking plate  145  which is normally disposed out of alignment with gas emitting openings  146  within the inflator  140 .  
         [0058]    In instances where a lower volume of inflation gas is desired within the air bag cushion  120 , the vent blocking plate remains out of alignment with the gas emitting openings  146  and a substantially unrestricted gas transmission path is thereby present between the gas emitting openings  146  and an aligned housing opening  147  thereby permitting a portion of the inflation gas to pass outwardly from the housing  142  rather than entering the air bag cushion  120 . As shown in dotted lines, upon activation of the variable inflation device  137  the vent blocking plate  145  is moved over the gas emitting openings  146 . In this covering position, the vent blocking plate  145  at least partially blocks the gas travel path between the gas emitting openings  146  and the housing opening  147  thereby causing an increased volume of inflation gas to be directed into the air bag cushion  120 .  
         [0059]    Preferably, the movement of the vent blocking plate  145  may also be used to release the tethering element  130  from fixed attachment within the housing  142  thereby permitting the air bag cushion  120  to assume an expanded inflated configuration as illustrated in FIG. 2B. In the embodiment illustrated in FIGS. 3A and 3B, the end cap  133  includes one or more extended pin elements  148  which project outwardly in the direction of movement of the vent blocking plate  145  (i.e. towards the gas emitting openings  146 ). During assembly, the loop element  132  attached to the tethering element  130  is passed over the pin elements  148  and held in place by an opposing wall  149  of the vent blocking plate  145 . As best seen in FIG. 3A, the wall  149  of the vent blocking plate preferably includes notched channels  150  for acceptance of cooperating pin elements  148  on either side of the end plate aperture  135 . Thus, a loop element  132  attached to a corresponding tethering element  130  may be passed over one or both pin elements  148  and thereafter be held in place between the end cap  133  and the opposing wall  149  of the vent blocking plate  145 .  
         [0060]    In operation, when the variable inflation device  137  is activated, the vent blocking plate  145  moves away from the end cap  133  and towards the gas emitting openings  146 . This action also causes the wall  149  of the vent blocking plate to move away from the end cap  133  thereby permitting the loop element  32  and attached tethering element  130  to slide over and away from the pin elements  148  as outward tension is applied. This sliding removal may be facilitated by the lower edge of the pin elements  148  being angled upwardly as shown. In some instances, the sliding removal may be facilitated still further by use of leaf spring elements  152  which include notched channels to engage the underside of the pin elements  148  forward of the loop elements  132 . The leaf spring elements  152  are arranged to normally apply a biasing force in the direction of movement of the vent blocking plate  145 . Thus, by placing the loop element  132  between the leaf spring elements  152  and the wall  149  of the vent blocking plate  145 , the leaf spring elements  152  will serve to push the loop elements  132  away from the pin elements  148  once the vent blocking plate  145  is moved away from the pin elements  148 .  
         [0061]    In FIGS. 4A and 4B, there is illustrated another tether release assembly in cooperative arrangement with a dynamic variable inflation device. Elements corresponding to those previously illustrated and described are designated by corresponding reference numerals in a  200  series. As shown in FIG. 4A, in this embodiment, the tethering element  230  is preferably passed in loop forming fashion through a clip element  256 . The tethering element  230  is held in fixed relation to the clip element by stitching  234  or other suitable attachment systems as will be known to those of skill in the art. As shown, the clip element  256  is of a split construction including a pair of flexible distending legs  257  with outwardly projecting hooks on the legs  257 . As illustrated, the legs  257  are separated from one another by a channel  258  opening into a wider circumference base portion  259 . A portion of the tethering element  230  extending away from the clip element  256  forms a length extending tether extension  223  which may be anchored in fixed or releasable relation to an anchor point (not shown) such as a stitched attachment to an internal or external surface of the air bag cushion. In operation, this length extending tether extension  123  acts as a mooring line to provide a secondary tethering restraint when the loop element clip element  256  is released in the manner as will now be described.  
         [0062]    The material forming the clip element  256  is preferably a plastic material having sufficient rigidity to retain its overall shape while nonetheless permitting the legs  257  to bend inwardly and outwardly to some degree. The clip element  256  is dimensioned such that the legs  257  may pass in substantially free sliding relation through the interior of a box channel element  260  projecting outwardly from the end cap  233 . The box channel element  260  preferably includes an acceptance opening  261  for introduction of a spreading pin  262  which is carried on the variable inflation device  237  and moves in conjunction with the vent blocking plate  245 . Upon assembly, the clip element  256  is passed into the box channel element  260  such that the base portion  259  is substantially in alignment with the acceptance opening  261  of the box channel element. The spreading pin  262  is thereafter inserted through the acceptance opening  261  and into the base portion  259  of the clip element  256 . The dimensions of the spreading pin  262  are preferably such that the legs  257  are caused to spread apart so as to hook below the lower edges of the box channel element. If desired, the end of the spreading pin  262  may be tapered thereby facilitating smooth insertion.  
         [0063]    In operation, upon activation of the variable inflation device and corresponding movement of the vent blocking plate  245  away from the end cap  233 , the spreading pin  262  is withdrawn from engagement with the clip element  256  thereby permitting the legs  257  to pull inwardly and disengage from hooked relation beneath the box channel element  260 . The tethering element  230  can thereby be pulled away from the stationary box channel element  260  as the air bag cushion  220  undergoes increased expansion.  
         [0064]    Another assembly for the retention and release of an air bag tethering element in conjunction with variable inflation control is illustrated in FIGS. 5A and 5B wherein elements corresponding to those previously illustrated and described are designated by reference numerals corresponding to those previously used in a  300  series. As shown in FIGS. 5A and 5B, the air bag assembly includes a tethering element  330  in adjoined relation to a loop element  332  as in the embodiments of FIGS. 3A and 3B. The variable inflation device  337  carries an upwardly extending forked extension  364  including a first upright bar  365  which is carried on the variable inflation device  337  and which moves in conjunction with the vent blocking plate  345 . The forked extension  364  further includes a second upright bar  366  located forward of the first upright bar  365  (i.e. further away from the gas emitting openings  346 ) and a cross bar  367  connecting the first and second upright bars  365 ,  366 .  
         [0065]    As illustrated, the orientation of the forked extension  364  is preferably such that upon assembly the first and second upright bars are disposed between outboard pin elements  348  such as described in relation to the embodiments in FIGS. 3A and 3B. Due to the pliable nature of the material forming, the loop element  332 , the loop element  332  may be passed in a generally sine wave configuration around the exterior of the outboard pin elements  348  and over the cross bar  367  between the first and second upright bars  365 ,  366  in the manner illustrated in FIG. 5B. Thus, the loop element  332  is secured against slippage away the outboard pin elements  348  prior to activation of the variable inflation device  337 .  
         [0066]    Upon activation of the variable inflation device  337 , both the vent blocking plate  345  as well as the forked extension  364  are moved away from the end cap  333  and the stationary pin elements  348 . During this movement, the second upright bar  366  pushes the loop element  332  over the ends of the pin elements  348 . Once the pin elements  348  have been cleared, the loop element is no longer restrained by either the pin elements  348  or by the forked extension  364 . Thus, the loop element  332  and the attached tethering element  330  are thereafter free to move away from the inflator  340  as the air bag cushion  320  expands outwardly.  
         [0067]    In addition to assemblies which utilize vent blocking plates which slide in axial relation to the inflator, it is likewise contemplated that release assemblies may incorporate attachment assemblies and cooperating vent blocking elements which move in substantially transverse relation to the inflator within a housing. A cut-away end view of an assembly incorporating a vent blocking element which is movable at substantially right angles to an elongate gas generating inflator is illustrated in FIGS. 6A and 6B wherein elements corresponding to those previously illustrated and described are designated by like reference characters in a  400  series.  
         [0068]    As shown in FIG. 6A, the air bag assembly  418  includes an elongate gas generating inflator  440  similar to those illustrated in previous embodiments arranged within a housing  442 . Extending across the housing at generally right angles to the inflator  440  is a vent blocking plate  445 . The vent blocking plate  445  includes one or more localized vent openings  468  which are normally disposed in alignment with corresponding vent openings  447  within the housing  442 . A tethering element  430  is attached to a locking tab element  469  secured in fixed opposing relation to a distal end of the vent blocking plate  445 . As illustrated, the locking tab element  469  preferably includes an outwardly projecting hooked prong  470  which is engageable through an opening in a mating stationary clip element  471 . If desired, a guide channel element  472  may be located adjacent to the mating clip element  471  to facilitate the travel of vent blocking plate  445  towards the hooked prong  470  in the manner to be described.  
         [0069]    In operation when enhanced volume is not required, the vent blocking plate  445  remains in a substantially stationary position such that a portion of the inflation gas emitted by the inflator  440  is expelled outwardly through the aligned vent openings  447 ,  468 . In the event that the crash severity and/or the size or position of the occupant to be protected indicates that an enhanced inflation profile is desirable, then a pressure generating squib  473  which may also be referred to as an initiator, may be activated thereby causing a pressure wave to move against the proximal end of the vent blocking plate  445  and pushing the vent blocking plate  445  away from the squib  473  and towards the opposing side wall of the housing  442 . Upon movement of the vent blocking plate  445 , the vent opening  468  within the vent blocking plate  445  moves out of alignment with the vent opening  447  in the housing as shown in FIG. 6B. Thus, the gas transmission path out of the housing is closed thereby forcing a greater quantity of inflation gas into the air bag cushion  420 . In addition, the forward movement of the vent blocking plate  445  causes compression of the hooked prong  470  towards the body of the locking tab element  469  thereby causing the hooked prong  470  to disengage from the mating clip element  471 . It is contemplated that this disengagement may be effected by either pushing the hooked prong  470  back through the mating clip element or by simply sheering the mating clip element off such that the locking tab element  469  is thereafter free to move away from the housing as illustrated in FIG. 6B. A degree of tethering restraint is preferably nonetheless maintained by length extending tether extension  423  which may be anchored in fixed or releasable relation to an anchor point such as a stitched attachment point  427  at an internal or external surface of the air bag cushion  420 .  
         [0070]    As shown, the distal end of the vent blocking plate  445  may have an angle substantially complementary with the angle of the hooked prong  470 . Such mating angles may promote efficient contacting relation between the hooked prong  470  and the moving vent blocking plate  445 . While a single hooked prong  470  is illustrated, it is to be understood that the locking tab element  469  may incorporate a number of prongs along its length so as to facilitate additional stability if desired.  
         [0071]    In FIGS. 7A and 7B, a cut-away end view similar to FIGS. 6A and 6B is provided illustrating another tether release assembly for use in conjunction with a variable inflation device within an air bag housing. In this embodiment like elements to those previously described are designated by like reference numerals in a  500  series. As shown, in this embodiment the tethering element  530  is attached to an elongate ring structure  575  which in turn is attached in frangible relation to a stationary base anchor element  576  held within a confinement chamber  577  along one side of the housing  542 . The tethering element  530  is thus normally held in locked relation by the elongate ring structure  575  and cooperating base anchor element  576  as shown in FIG. 7A.  
         [0072]    In instances when an enhanced expanded air bag profile is desired, the pressure generating squib or initiator  573  is fired thereby forcing the distal end of the vent blocking plate  545  forward and causing the elongate ring  575  to sheer away from the locked base anchor element  576 . As shown, this sheering operation releases the tethering element  530  thereby allowing movement away from the stationary base anchor element  576  and the housing  542 . A degree of tethering restraint is preferably nonetheless maintained by length extending tether extension  523  which may be anchored in fixed or releasable relation to an anchor point such as a stitched attachment point  527  to an internal or external surface of the air bag cushion  520 .  
         [0073]    As shown, the elongate ring  575  may include an internal bridging element  578  to prevent detachment from the tether element  530 . During the sheering operation the vent openings  568  within the vent blocking plate  545  are moved out of alignment with the vent openings  547  within the housing thereby causing a greater percentage of inflation gas to be directed into the air bag cushion  520  in the manner as previously described in relation to other embodiments.  
         [0074]    In FIGS. 8A and 8B there is illustrated in cut-away end view yet another arrangement for selective retention of an air bag tethering element. In this embodiment, elements corresponding to those previously illustrated and described are designated by like reference numerals in a  600  series. As shown, the air bag assembly  618  includes a tethering element  630  which is attached to a pin element  678 . The pin element  678  extends through a stationary mating sleeve  679 . One or more frangible sheer tabs  680  extend between the pin element  678  and the sleeve  679 . As shown, the orientation of the pin element  678  within the sleeve  679  is in generally opposing relation to the distal end of the vent blocking plate  645 . Thus, upon movement of the vent blocking plate  645  by the pressure generating squib or initiator  673 , the pin element  678  is pushed out of the sleeve  679  as the sheer tabs  680  are broken off. Concurrently, the vent openings  647  and  668  become misaligned thereby increasing the percentage of inflation gas which may enter the inflatable cushion  620  (FIG. 8B). Following disengagement from the sleeve  679  the pin element  678  and attached tether element  630  are thereafter free to move away from the stationary sleeve  679  and the housing  642  in conjunction with the inflation of the air bag cushion  620 . A degree of tethering restraint is preferably nonetheless maintained by length extending tether extension  623  which may be anchored in fixed or releasable relation to an anchor point such as a stitched attachment point  627  to an internal or external surface of the air bag cushion  620 .  
         [0075]    In FIGS.  9 A- 9 D there is illustrated yet another arrangement for the selective retention and release of an air bag tethering element. In this embodiment, elements corresponding to those previously illustrated and described are designated by like reference numerals in a  700  series. In this arrangement, the air bag assembly  718  incorporates a vent blocking plate  745  including a hook-forming distal end which moves in substantially transverse relation to the inflator  740 . The tether element  730  is formed into a loop at one end and passed over a fixed anchoring hitch element  781  projecting in the direction of travel of vent blocking plate  745 . As best seen in FIG. 9B, the vent blocking plate  745  includes a generally “C” shaped hook  782  at the distal end. As illustrated, the hook  782  holds the tether element  730  on the hitch element  781  until it is moved away by firing the squib or initiator  773 . In this orientation, the tethering element  730  is prevented from moving away from its anchored position thereby constricting the available inflation diameter of the overlying air bag cushion  720  to which the tethering element  730  is operatively connected. While a substantially straight sided “C” shaped hook  782  may be utilized to hold the tethering element  730  in place, it is also contemplated that other geometries such as a reverse “L” opening  782 ′ as shown in FIG. 9C may likewise be utilized to further enhance ability of the vent blocking plate  745 ′ to hold the tether in place prior to activation.  
         [0076]    As best seen in FIG. 9D, when the vent blocking plate is advanced, the tethering element  730  is pushed off of the end of the anchoring hitch element  781  and is thereafter free to move out of the gap within the hook  782 ,  782 ′ and away from the housing  742  as the air bag cushion  720  expands. A degree of tethering restraint is preferably nonetheless maintained by length extending tether extension  723  which may be anchored in fixed or releasable relation to an anchor point such as a stitched attachment point  727  to an internal or external surface of the air bag cushion  720 . Concurrently with the release of the tethering element, the vent opening  747  within the housing  742  is at least partially closed off thereby directing an enhanced percentage of inflation gas into the air bag cushion  720 .  
         [0077]    In FIGS. 10A, 10B, and  10 C, there is illustrated yet another arrangement for the selective retention and extension inducing release of an air bag tethering element. In this embodiment, elements corresponding to those previously illustrated and described are designated by corresponding reference numerals within an  800  series. As illustrated, in this embodiment, the vent blocking plate  845  is arranged along one side wall of the housing  842  within a support channel  883  as shown. Such a side arrangement is illustrated in U.S. Pat. No. 6,161,866 to Ryan et al. the teachings of which are incorporated by reference as if fully set forth herein. As shown, in this embodiment a stationary pin element  848  extends away from the side wall of the housing  842  within the boundaries of the support channel  883 . A looped end of a tethering element  830  is disposed over the pin element  848 . A portion of the tethering element  830  extending away from the pin element  848  forms a length extending tether extension  823  which may be anchored in fixed or releasable relation to an anchor point (not shown) such as a stitched attachment to the interior or exterior surface of the air bag cushion.  
         [0078]    The pin element  848  may be angled upwardly if desired so as to facilitate the sliding disengagement of the tethering element  830  upon application of a tensioning force. A break-away attachment strip  884  may be used to hold the tethering element  830  in a substantially planar relation to the side wall if desired. The side wall of the housing  842  also includes an opening  847  within the boundaries of the support channel  883 . The vent blocking plate  845  includes a key slot  885  extending from the upper edge into the interior of the vent blocking plate  845 . As illustrated, the key slot  885  includes a nose projection  886  projecting in the direction of sliding movement by the vent blocking plate  845 . The vent blocking plate  845  also includes a vent opening  868  as shown.  
         [0079]    As best seen through simultaneous reference to FIGS.  10 A- 10 C, upon assembly, the pin element  848  is disposed within the nose portion  886  of the key slot  885  with the portion of the tethering element extending away from the pin element  848  being held behind the vent blocking plate  845  between the side wall and the vent blocking plate (FIG. 10B). In this normal configuration, the vent openings  847  and  868  within the side wall and vent blocking plate are substantially aligned such that a portion of inflation gas emitted from the gas emitting openings  846  is carried outwardly from the housing  842 . In operation, the arrangement as illustrated in FIG. 10B is maintained for deployment of air bag cushions under circumstances where a shallow restrained profile is desired. In that arrangement, the tethering element  830  is secured against movement away from the pin element  848  by the overlying portion of the vent blocking plate  845 .  
         [0080]    In the event that a release of the tethering element  830  is desired, an initiator or squib  873  is fired thereby projecting the vent blocking plate  845  in sliding relation through the support channel  883  until contacting a stop pin  887  (FIG. 10C). As shown, the forward movement of the vent blocking plate  845  causes the nose portion  886  to be displaced relative to the stationary pin element  848  thereby bringing the pin element  848  into alignment with an open portion of the key slot  885 . In this arrangement, the tethering element  830  is no longer held beneath the sliding vent blocking element and is thereby free to slide off of the pin element  848  as shown. In addition to the release of the tethering element  830 , the sliding movement of the vent blocking element  845  also results in the substantial misalignment of the vent openings  847 ,  868  thereby closing off the gas transmission path through the housing  842  and causing a greater percentage of inflation gas to be directed into the air bag cushion.  
         [0081]    In FIGS.  11 A- 11 D, there is illustrated still another arrangement for the selective retention and release of a tethering element. In this embodiment, elements corresponding to those previously illustrated and described are designated by like reference numerals in a  900  series. As shown in FIG. 11A, in this assembly a sliding vent blocking plate  945  is arranged in sliding relation within a support channel  983  extending along a side wall of the housing  942 . The vent blocking plate  945  may be moved within the support channel by activation of a squib  973  or other initiator. As best seen in FIG. 11C and 11D, a looped end of a tethering element  930  is attached to the vent blocking plate  945  by a breakable attachment element  988  such as a piece of plastic fixed in a loop-forming fashion to the surface of the vent blocking plate  945 . The tethering element  930  is further held in place by a stationary clip element  989  which is mounted to the side wall of the housing. As shown, the stationary clip element  989  includes a narrow finger projection  990  which projects away from the body of the clip element in the direction of movement of the vent blocking plate  945 . As shown, the vent blocking plate also includes a vent opening  968  which may be aligned with a corresponding vent opening  947  within the housing  942 .  
         [0082]    Upon assembly, the finger projection  990  is arranged to extend through the looped end of the tethering element  930  in overlying relation to the breakable attachment element  988  (FIG. 11C). In this configuration, the finger projection  990  supports the tethering element  930  against outward movement. In this restrained arrangement, the vent openings  968  and  947  are preferably substantially aligned as shown in FIG. 11B thereby permitting a portion of the inflation gas emitted by the inflator  940  to be discharged through the housing  942  without entering an overlying air bag cushion.  
         [0083]    In the event that release of the tethering element  930  is desired, the squib  973  is fired thereby projecting the vent blocking plate  945  in sliding relation in the direction of the stationary finger projection  990 . Upon the occurrence of such movement, the breakable attachment element  988  pulls the tethering element  930  out of engagement with the finger projection  990  as shown in FIG. 11D. However, once disengagement from the finger projection is effected, the strength of the breakable attachment element  988  is insufficient to retain the tethering element  930  in place and the tethering element  930  is thereby released from its previous attachment at the vent blocking plate  945 . As illustrated, the movement of the vent blocking plate also results in the misalignment of the vent openings within the vent blocking plate and housing thereby causing a greater percentage of inflation gas to be directed into the overlying air bag cushion as increased expansion takes place. According to the illustrated arrangement, a portion of the tethering element  930  extending away from the loop forms a length extending tether extension  923  which may be anchored in fixed or releasable relation to an anchor point (not shown) such as a stitched attachment to the interior or exterior surface of the air bag cushion so as to nonetheless maintain a degree of tethering restraint.  
         [0084]    In FIGS. 12A and 12B, there is illustrated still another arrangement for the selective retention of a tethering element. In this embodiment, components corresponding to those previously illustrated and described are designated by like reference numerals in a  1000  series. In this embodiment the air bag assembly  1018  (shown in cut-away end view) includes an elongate inflator  1040  such as illustrated in FIGS. 10A and 11A arranged along the length of a housing  1042 . A rotatable vent blocking element  1045  having a generally cupped configuration is arranged over the neck portion of the inflator in substantially opposing relation to the circumferentially arranged gas emitting openings  1046 . As will be appreciated, the inflator is of a configuration substantially as illustrated in FIGS. 10A and 11A with the view of FIG. 12A being inwardly at the narrow end of the inflator  1040 .  
         [0085]    It is contemplated that the vent blocking element  1045  may swing freely about the neck of the inflator. As shown, the tethering element  1030  is held in looped relation over a displaceable squib element  1073  which may be fired on demand. As shown, the squib element  1073  is preferably disposed slightly below the centerline of the radius of rotation for the vent blocking element  1045 . Accordingly, upon activation of the squib  1073  a pressure force directed against the vent blocking element  1045  is translated into a rotational movement which brings the vent blocking element  1045  downward into the position illustrated in FIG. 12B. As illustrated, the force of activation simultaneously causes the squib  1073  to be displaced away from the vent blocking element  1045  thereby providing clearance to permit the rotation. At the same time, the tethering element  1030  is released from engagement with the squib  1073 . Once the vent blocking element  1045  is rotated into a blocking relation with respect to the vent opening  1047  within the housing  1042 , this position may thereafter be maintained by engagement with a latch element  1091  which cooperatively hooks over the leading edge of the vent blocking element  1045 . Following disengagement from the squib  1073 , the tether element  1030  is thereafter free to move in conjunction with the inflation of the air bag cushion  1020 . A degree of tethering restraint is preferably nonetheless maintained by length extending tether extension  1023  which may be anchored in fixed or releasable relation to an anchor point such as a stitched attachment point  1027  to an internal or external surface of the air bag cushion  1020 .  
         [0086]    In FIGS. 13A, 13B and  13 C there is illustrated another embodiment wherein components corresponding to those previously described are designated by like reference numerals in an  1100  series. In this embodiment the vent blocking element  1145  is arranged normally forward of gas emitting openings  1146  within the inflator  1140 . As shown, the inflator  1140  is arranged at one side of the housing  1142  within a cradling curved contour portion  1143 . Such an arrangement may be beneficial in providing substantial room to the side of the inflator for packaging of the air bag cushion  1120  prior to inflation. Within the curved contour portion  1143  a plurality of slotted vent openings  1147  are disposed. Of course only a single vent opening may likewise be utilized if desired. According to the illustrated embodiment, the vent openings are substantially aligned with the gas emitting openings  1146  although they may be positioned outboard of such openings if desired.  
         [0087]    As best illustrated in FIG. 13B, this embodiment is in the form of a relatively compact linear arrangement so as to facilitate efficient space utilization. In the illustrated arrangement, a pyrotechnic squib or other pressure generating initiator  1173  is located within an elongate hollow stud element  1138  extending away from the neck of the inflator  1140 . A nut  1139  is disposed in overlying relation to the end of the elongate hollow stud element. Upon activation, the initiator  1173  applies pressure to a displaceable sleeve element  1141 . As shown, the sleeve element  1141  carries shear tabs  1151  which are normally held in slots located within the hollow stud element  1138 . Thus, upon the application of pressure by the initiator, the displaceable sleeve moves in the direction of the arrow and towards the gas emitting openings. According to one potentially preferred practice, it is contemplated that the sleeve element may be in the form of an insert molded part having a metallic substrate overmolded with plastic. Such a construction is believed to reduce noise generation while nonetheless providing superior strength during activation.  
         [0088]    As shown, the sleeve element  1141  is affixed to a slide element  1153  which in turn is affixed to the vent blocking element  1145  such that upon movement of the sleeve element  1141 , the vent blocking element undergoes a corresponding displacement. The slide element travels within slots  1155  of enlarged configuration at the top and bottom of the hollow stud element  1138 . As illustrated in dotted lines, the stroke length of this movement is such that the vent blocking element is moved into a blocking relation between the gas emitting openings  1146  and the vent openings  1147 . Upon this occurrence, an increased quantity of inflation gas is directed into the air bag cushion  1120 .  
         [0089]    As best illustrated trough simultaneous reference to FIGS. 13A and 13B, tether elements  1130  are formed into internal loop structures  1125  maintained by stitching  1134  or other suitable attachment structures. The internal loop structures  1125  are held in sliding relation over complementary retaining studs  1148  extending inwardly from the end wall of the housing  1142 . These retaining studs  1148  are preferably swaged into the end wall and are surrounded by reinforcing beads  1119  of thickened material (FIG. 13C) so as to provide added strength when retaining the tethers.  
         [0090]    The retaining studs  1148  extend through aligned openings within a double walled carrier  1164  such that the loop structures are normally held in place between opposing carrier walls  1165 ,  1166 . As best seen in FIG. 13C, the carrier  1164  is attached in snap-in relation to the end wall by snap elements  1117 . In addition, a threaded carrier stud  1121  extends from the end wall through the carrier  1164  for attachment to the slide element  1153  by use of a press nut  1113 . The slide element  1153  has sufficient thickness and structural integrity so as to support the carrier  1164 . Thus, upon activation of the initiator, the transitional movement is communicated through the slide  1153  which in turn moves the carrier away from the end cap.  
         [0091]    As best seen in FIG. 3C, the movement of the carrier  1164  pushes the loop structures  1125  off of the retaining studs thereby allowing the tethers to be extended to a greater operational length as the vent blocking element  1145  is positioned between the gas outlet openings in the inflator and the vent openings  1147  in the housing  1142 . It is contemplated that the coverage by the vent blocking element  1145  may be completely over the vent openings  1147  or may be partially over such openings depending upon desired inflation characteristics. As with prior embodiments, it is contemplated that length extending tether extensions  1123  may acts as mooring lines to provide a secondary tethering restraint by maintaining attachment to the air bag cushion or other anchoring location when the loop elements  1125  are released.  
         [0092]    Still another embodiment is illustrated in FIGS. 14A and 14B wherein elements corresponding to those previously described are designated by corresponding reference numerals in a  1200  series. In this embodiment, the housing  1242  is formed with an elongate channel  1292  running along at least a portion of the length of the housing  1242 . It is contemplated that the channel  1292  may be formed integrally with the remainder of the housing  1242  or may be a separate attached element. As shown, the channel  1292  has an interior which is bounded by arched side walls such that an element may slide freely within the channel  1292  while nonetheless remaining constrained within the interior. A slotted opening of width less than the interior diameter extends along the length of the channel  1292 . The channel  1292  is discontinuous over its length and includes at least one break  1294 . The channel is configured so as to accept therein a push rod  1293  which may be advanced through the channel by means of a carrier  1273  operatively connected to a squib activated vent blocking element  1245 . The push rod  1293  may also be operatively connected to a tether restraining element carried within the channel  1292 . It has been found that the broken configuration of the channel  1292  permits the utilization of a number of tether retaining and release assemblies which are carried within the channel  1293  and are thereafter pushed into the gap  1293  to result in disengagement of the tether from attachment at the housing  1242  as the vent blocking element  1245  is advanced from its normal position in FIG. 14A wherein the vents  1247  are open and the tether  1230  is restrained to a restricted length to the position in FIG. 14B where the vents are closed and the tether is adapted for extension to an enhanced operative length. As with prior embodiments, it is contemplated that length extending tether extensions  1223  may acts as mooring lines to provide a secondary tethering restraint by maintaining attachment to the air bag cushion or other anchoring location when the tethering elements  1230  are released.  
         [0093]    A first contemplated arrangement for a moveable tether restraining element as may be used in the arrangement of FIGS. 14A and 14B is illustrated in FIGS. 15A and 15B wherein the terminal end of a tethering element  1330  is clamped within a clamshell element  1395 . As shown, the clamshell element  1395  may include a detent element  1396  over which an opening within the tethering element  1330  may be disposed. The detent element  1396  may cooperatively mesh with an indentation  1397  such that a substantially sealed enclosure may be achieved. In operation, the clam shell element  1393  is normally carried within the channel  1292  with the closed hinge edge being affixed to the distal end of the push rod  1293  and the mouth opening projecting towards the gap  1294 . Upon movement of the push rod  1293 , the clamshell element  1395  may be projected through the channel  1292  until reaching the gap  1294 . As clamshell element  1395  emerges into the gap, a progressive opening of the clamshell element may take place. As will be appreciated, this opening is caused to occur by the tension applied to the tethering element  1330  as the overlying airbag cushion (not shown) is inflated. Upon completion of the stroke of the push rod  1293 , the clamshell element is preferably held in place by attachment to the push rod  1293 .  
         [0094]    An alternative tether restraining assembly for use in the arrangement of FIGS. 14A and 14B is illustrated in FIGS. 16A and 16B. As illustrated, in this arrangement a restraining tether  1430  includes one half of a hook and loop fabric  1498  which is mated to a cooperating complementary half of the a hook and loop fabric  1499  within a clamshell element  1497 . The clamshell element  1497  is normally housed within the channel  1492  in the manner such as described in relation to FIGS. 15A and 15B such that it cannot be opened. However, upon activation the clamshell element may be pushed into the gap  1294  at which point the restraint against opening is progressively eliminated. As will be appreciated, while the clamshell element  1497  is in the closed position, the tearing action required to separate the cooperating surfaces of the hook and loop fabric  1498  and  1499  may not be achieved. However, as opening occurs, a tensioning force applied to the tethering restraint  1430  gives rise to the requisite tearing action thereby permitting release of the tethering restraint  1430 . Upon completion of the stroke of the push rod  1293 , the clamshell element  1497  is preferably held in place by attachment to the push rod  1193 .  
         [0095]    In FIGS. 17A and 17B, several embodiments of hooked tethering attachment elements for use in the arrangement of FIGS. 14A and 14B are illustrated. In the embodiment of FIG. 17A, a plug element  1501  is illustrated which includes a hook structure  1502  over which the air bag tethering element  1530  is held. Upon being pushed into the gap  1294 , the plug element  1501  is permitted to rotate due to the application of force by the tethering element  1530  thereby causing the tethering element  1530  to be released. A corresponding structure is illustrated in FIG. 17B wherein the plug element  1501 ′ utilizes a detent element  1503 ′ which may be rotated out of engagement by the application of tension to the tethering element  1530 ′ once the plug element  1501 ′ is pushed into the gap  1294 .  
         [0096]    In FIG. 18 there is illustrated yet another tether attachment structure useful in the arrangement of FIGS. 14A and 14B incorporating a channel  1292  extending along the housing  1242 . In this embodiment, the tethering restraint  1630  is disposed around a carrier element  1605  such as a ball or plug which rides within the channel  1292 . Upon being pushed into the gap  1294  by the push rod  1293  the tethering restraint is free to move outwardly away from the channel  1292  as inflation of the corresponding air bag cushion takes place.  
         [0097]    It is to be understood that while the present invention has been illustrated and described in relation to potentially preferred embodiments, constructions and procedures, that such embodiments, constructions and procedures are illustrative only and the present invention is in no event to be limited thereto. Rather it is contemplated that modifications and variations embodying the principles of the present invention will no doubt occur to those skilled in the art. It is therefore contemplated and intended that the present invention shall extend to all such modifications and variations as may incorporate the broad aspects of the present invention within the full spirit and scope thereof.