Patent Publication Number: US-8973295-B2

Title: Trigger mechanism

Description:
FIELD OF THE INVENTION 
     This invention relates generally to the field of firearms, and specifically an adaptive device for activating a firearm&#39;s trigger. 
     BACKGROUND OF THE INVENTION 
     Mankind has used firearms for hunting, self-defense, law enforcement, and military purposes since the inception of firearms as early as the 14 th  Century. In many locations, including the United States of America, the right to bear arms is a protected individual right. For example, the Second Amendment of the United States Constitution delineates, “the right of the people to keep and bear arms shall not be infringed.” Firearms are just as important in modern times as they have ever been. 
     The fundamental design of most firearms includes a stock, barrel, magazine for storing and loading bullets, and a trigger mechanism. Most firearms are designed to fire, or discharge bullets, with a finger-activated trigger. Persons with physical impairments, such as a lack of physical dexterity in the hands or fingers, may not be able to operate a finger-activated trigger. In addition, some people may prefer to operate a firearm with a non-finger activated trigger to improve the user experience including to avoid trigger burn, or to improve shooting accuracy. Thus, there is a need for a non-finger activated trigger mechanism to adapt the use of firearms for persons with physical impairments and to improve the user experience. 
     This invention provides a novel solution for a non-finger activated trigger mechanism including an ergonomic bite plate assembly, a spring-tensioned cable, a rod actuator assembly, a lanyard system with a quick-disconnect feature for holding the bite plate assembly for easy access, and a storage feature for safely storing the bite plate assembly when the firearm is not in use. 
     BRIEF SUMMARY OF THE INVENTION 
     One embodiment of the invention is an adaptive mechanism for activating a firearm&#39;s trigger comprising a bite-activated trigger assembly, a cable assembly, an actuator assembly, and a storage assembly. First, the firearm&#39;s trigger is modified to include an actuator assembly, which includes support plates and an actuator. One end of the actuator is pivotally attached to a first support plate. A second support plate includes a mating feature to accept the opposite end of the actuator. The opposite end of the actuator includes a mating feature to join one end of a cable assembly, referred to as the cable assembly&#39;s firearm-end. The cable assembly includes an adjustable spring that is used to push the actuator so the actuator&#39;s static position is not engaged with the firearm&#39;s trigger. The first and second support plates are placed on separate sides of the firearm&#39;s trigger. The first and second support plates are fastened together on each side of the firearm&#39;s trigger using fasteners, such as screws. When properly assembled, the actuator assembly is mated adjacent to the firearm&#39;s trigger in such a manner that the actuator is not exerting a force significant enough to activate the firearm&#39;s trigger. 
     Next, the opposite end of the cable assembly, referred to as the bite-trigger end, is attached to the bite trigger assembly. The cable assembly is designed such that the overall length of cable assembly is sufficient to attach the cable&#39;s firearm end to the actuator and the bite-trigger end to the bite trigger, and sufficient to enable the operator to use the firearm. The overall length of cable assembly is also optimized such that the cable will be pulled when the operator bites down on the bite trigger assembly enough to activate the firearm&#39;s trigger with the actuator. The overall length of the cable assembly may be optimized for specific firearm types, or the overall length of the cable assembly may be designed to work with a wide variety of firearms. 
     The bite trigger assembly includes two bite plates that are pivotally joined together near the centerline of the bite plates. The bite trigger assembly also includes a spring. The spring is attached to the bite plates and designed to hold the two bite plates substantially parallel to each other during the static position. The end of the bite trigger assembly opposite to where the cable assembly is attached may include a mouth guard. The mouth guard may include two separate pieces of compressible material, such as a soft polymer, each attached to a bite plate. A safety feature may also be included in the bite trigger assembly at the end of the bite trigger assembly opposite to where the cable assembly is attached. The safety feature is designed to prevent an accidental discharge of the firearm. The safety feature is designed such that the operator is able to disengage the safety feature with the use of the mouth or tongue. The bite trigger assembly also includes a feature to mount with the lanyard assembly. 
     Next, the bite-activated trigger assembly includes a lanyard that is used to attach the bite trigger assembly at times when the operator is not ready to activate the firearm&#39;s trigger. The lanyard consists of a quick disconnect mounting feature attached to a rope lanyard, such as a nylon rope. The lanyard&#39;s quick disconnect mounting feature mates with the bite trigger assembly&#39;s lanyard mounting feature. The lanyards&#39; quick disconnect mounting feature is designed to allow the operator to disconnect the bite trigger assembly using a biting action, or other hands-free activated quick disconnect feature. 
     Finally the bite-activated trigger assembly includes a storage assembly that is used to stow the bite trigger assembly when the firearm is not in use. The storage assembly includes a housing designed to mate the entire bite trigger assembly. The housing includes side walls designed to protect the bite trigger assembly from being accidentally activated while the bite-activated trigger assembly is not in use. For example, the housing may be formed from at least three side walls with an opening designed to fit the bite trigger assembly within. One of the side walls includes a bite trigger assembly mating feature to mate with the bite trigger assembly&#39;s mating feature. The storage assembly also includes a mounting feature designed to enable the mounting feature to attach to the firearm. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Features and advantages of the claimed subject matter will be apparent from the following detailed description of embodiments consistent therewith, which description should be considered with reference to the accompanying drawings, wherein: 
         FIG. 1  is a diagram of an exemplary embodiment illustrating a system for activating a firearm&#39;s trigger using a non-finger activated trigger in accordance with the teachings of the present invention; 
         FIG. 2  is a diagram of an exemplary embodiment illustrating an actuator assembly in accordance with the teachings of the present invention; 
         FIG. 3  is a diagram of an exemplary embodiment illustrating a bite trigger assembly in accordance with the teachings of the present invention; 
         FIG. 4  is a diagram of an exemplary embodiment illustrating a lanyard assembly in accordance with the teachings of the present invention; 
         FIG. 5  is a diagram of an exemplary embodiment illustrating a storage assembly in accordance with the teachings of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The following describes the details of the invention. Although the following description will proceed with reference being made to illustrative embodiments, many alternatives, modifications, and variations thereof will be apparent to those skilled in the art. Accordingly, it is intended that the claimed subject matter be viewed broadly. Examples are provided as reference and should not be construed as limiting. The term “such as” when used should be interpreted as “such as, but not limited to.” 
     The invention provides a novel solution for modifying an existing firearm for use by operators with physical impairments, such as a lack of physical dexterity in the hands or fingers, that prevent the operator from using a finger-activated trigger. The invention is also applicable to operators that prefer to operate a firearm with a non-finger activated trigger to improve the user experience including to avoid trigger burn, or to improve shooting accuracy. 
       FIG. 1  is a diagram of an exemplary embodiment for a system  1000  for activating a firearm&#39;s trigger  1610  comprising a bite trigger assembly  1300 , a cable assembly  1700 , an actuator assembly  1200 , and a storage assembly  1500 . First, the firearm&#39;s trigger  1610  is modified to include an actuator assembly  2000  (referring to  FIG. 2 ), which includes support plates  2100  and an actuator  2200 . One end of the actuator  2200  is pivotally attached to a first support plate  2210 . The actuator  2200  may be made from a solid metal, composite, plastic, or other structurally rigid material. The geometry of the actuator  2200  is optimized to fit within the trigger well  1610  (referring to  FIG. 1 ) of the firearm  1600 . Ideally, the geometry is sized so that an actuator design could be used for several different firearm types. The actuator  2200  is attached to the first support plate  2100  in a manner that allows the actuator to pivot freely to engage with the firearm&#39;s trigger  2500  and pivot back into the static position, as shown in FIG.  2 &#39;s Cross Sectional View. For example, the pivot end of the actuator  2210  may include a through hole with a similar through hole in the support plate. A fastener, such as a cotter pin or screw, may be inserted into the through holes to hold the actuator  2200  to the support plate  2100  while still allowing the actuator  2200  to pivot and engage the firearm&#39;s trigger  2500 . 
     A second support plate  2150  includes a mating feature to accept the opposite end of the actuator. The mating feature may include a slot that allows the actuator  2200  to pivot and engage the firearm&#39;s trigger  2500 , as well as pivot back to the static position. 
     The opposite end of the actuator  2200  includes a cable mating feature  2210  to join one end of the cable assembly, referred to as the cable assembly&#39;s firearm-end  2700 . The cable assembly includes an adjustable spring  2300  that is used to push the actuator  2200  so the actuator&#39;s static position is not engaged with the firearm&#39;s trigger  2500  (as shown in  FIG. 2 ). The spring  2300  may comprise a tension spring formed from a helical metal wire, or any other type of compressive material. The spring  2300  is designed such that the tensile load is sufficient enough to push the actuator  2200  away from the firearm&#39;s trigger  2500 . The tensile load is also optimized such that the spring  2300  can be compressed when the operator  1100  (referring to  FIG. 1 ) bites down on the bite trigger assembly  1300 . The tensile load is again applied to the actuator  2200  when the operator  1100  stops biting down on the bite trigger assembly  1300 , thus causing the actuator  2200  to be pushed away from the firearm&#39;s trigger  2500 . 
     The first support plate  2100  and second support plate  2150  are placed on separate sides of the firearm&#39;s trigger  2500 . The first support plate  2100  and second support plate  2150  are fastened together on each side of the firearm&#39;s trigger  2500  using fasteners, such as screws. When properly assembled, the actuator assembly  2000  is mated adjacent to the firearm&#39;s trigger  2500  in such a manner that the actuator  2200  is not exerting a force sufficient enough to activate the firearm&#39;s trigger  2500 , as shown in  FIG. 2 . 
     The support plates may be formed from a single piece of material, or for ease of manufacturing, each support plate may be comprised of several thinner sheets that form the overall geometry of the support plate. This may be beneficial in allowing slots and mounting features to be included in the support plate to facilitate mating the actuator and mounting the support plates on to the firearm. The support plates may be made from metal, composite, wood, or any type of material sufficient to be fabricated with the geometric detail and support the associated forces and loads. 
     Next, the opposite end of the cable assembly, referred to as the bite-trigger end  3700 , is attached to the bite trigger assembly  3000  (referring to  FIG. 3 ). The cable assembly  1700  is designed such that the overall length of cable assembly  1700  is sufficient to attach the cable&#39;s firearm end  2700  to the actuator  2200  and the bite-trigger end  3700  to the bite trigger assembly  3000 , and sufficient to enable the operator  1100  to use the firearm  1600 . The overall length of cable assembly  1700  is also optimized such that the cable assembly  1700  will be pulled when the operator  1100  bites down on the bite trigger assembly  1300  enough to activate the firearm&#39;s trigger with the actuator assembly  1200 . The overall length of the cable assembly  1700  may be optimized for specific firearm types, or the overall length of the cable assembly  1700  may be designed to work with a wide variety of firearms. The ends of the cable are designed to attach to appropriate mating components using grommets, or other suitable cable fasteners common in cable systems. 
     The cable assembly  1700  may be comprised of several cable layers, such as a Bowden cable assembly which is commonly used in mechanical systems as a flexible cable used to transmit mechanical force by the movement of an inner cable relative to a hollow outer cable housing. The inner cable is typically composed of steel braided wires. The housing is generally made of a composite construction including a helical steel wire, lined with nylon, and with a plastic outer sheath. The linear movement of the inner cable is used to transmit a pulling force. For example, when the operator  1100  bites down on the bite trigger assembly  1300 , the inner cable transmits the pulling force needed to pull the actuator  2200  toward the firearm&#39;s trigger  2500  enough to activate the firearm&#39;s trigger  2500 . The cable assembly  1700  may also include provisions for adjusting the cable tension using an inline hollow bolt, such as a barrel adjuster, which lengthens or shortens the cable housing relative to a fixed anchor point. For adjustment purposes, lengthening the housing tightens the cable and shortening the housing loosens the cable. 
     The bite trigger assembly  3000  includes two bite plates  3100  that are pivotally joined  3200  together near the centerline of the bite plates  3100 . The bite plates  3100  may be formed from a single piece of material, or for ease of manufacturing, each bite plate  3100  may be comprised of several thinner sheets that form the overall geometry of the bite plate  3100 . This may be beneficial in allowing slots and mounting features to be included in the bite plate  3100 . The bite plates  3100  may be made from metal, composite, wood, or any type of material sufficient to be fabricated with the geometric detail and support the associated forces and loads. The bite plates  3100  also include features to help guide the cable and to clamp the end of the cable assembly  3700 . 
     The bite trigger assembly  3000  also includes a spring  3300 . The spring  3300  is attached to the each bite plate  3100  and designed to hold the two bite plates  3100  substantially parallel to each other during the static position, as shown in  FIG. 3 . The spring  3300  may be comprised of torsion springs placed between the two bite plates  3100  and designed such that the bite plates  3100  are held substantially parallel to each other when the operator  1100  is not applying a biting force to the bite plate assembly  3000 . The spring  3300  may be fabricated from a helical metal coil wire. The spring  3300  may also be formed from a compressive spring, such as a compressive spring formed from a helical metal coil wire, or a compressive foam material. More than one spring  3300  may be used to provide a broader range of spring loads, such as using multiple springs with different spring constants in parallel. Additionally springs may be placed at both ends of the bite trigger assembly to better position the bite plates  3100  parallel to each other during the static position. 
     The end of the bite trigger assembly  3000  opposite to where the cable assembly  3700  is attached may include a mouth guard  3400 . The mouth guard  3400  may include two separate pieces of compressible material, such as a soft polymer, each attached to a bite plate  3100 . The mouth guard  3400  is designed to provide the operator  1100  a tooth-friendly surface to bite down on the bite trigger assembly  3000 . The mouth guard  3400  is needed because the bite plates  3100  may be comprised of a solid material such as metal, composite, or hard plastics. The mouth guard  3400  pieces are attached to the bite plates  3100  sufficiently such that the mouth guard  3400  pieces do not easily become detached from the bite plates  3100 . For example, the mouth guard  3400  pieces may be attached to the bite plates  3100  using a permanent, or semi permanent epoxy, cement, glue, adhesive tape, fastener, or a grommet may be included in the mouth guard&#39;s geometry that is pushed into a mating through hole in the bite plates  3100 . 
     A safety feature may also be included in the bite trigger assembly  3000  at the end of the bite trigger assembly opposite to where the cable assembly is attached. The safety feature is designed to prevent an accidental discharge of the firearm. The safety feature is designed such that the operator is able to disengage the safety feature with the use of the mouth or tongue. 
     The bite trigger assembly also includes a lanyard mounting feature  3500  to mount with the lanyard assembly. The lanyard mounting feature  3500  may include a through hole in the bite plate designed to allow a clip to connect to the through hole. 
     Next, the system  3000  includes a lanyard assembly  4000  (referring to  FIG. 4 ) that is used to attach the bite trigger assembly  4500  at times when the operator  4100  is not ready to activate the firearm&#39;s trigger. The lanyard assembly  4000  consists of a quick disconnect mounting feature  4300  attached to rope  4200 , such as a nylon rope. The lanyard&#39;s quick disconnect mounting feature  4300  mates with the bite trigger assembly&#39;s lanyard mounting feature  3500 . The lanyards&#39; quick disconnect mounting feature  4300  is designed to allow the operator  4100  to disconnect the bite trigger assembly  4500  using a biting action, or other hands-free activated quick disconnect feature. Alternatively, commercial-over-the-shelf lanyards may be used including models with quick disconnect clips. 
     Finally the system includes a storage assembly  5000  that is used to stow the bite trigger assembly  5500  when the firearm is not in use. The storage assembly  5000  includes a mounting housing designed  5200  to stow the entire bite trigger assembly  5200 , as shown in  FIG. 5  b. The mounting housing  5200  includes side walls  5110  designed to protect the bite trigger assembly from being accidentally activated while the bite-activated trigger assembly is not in use. For example, the mounting housing  5200  may be formed from at least three side walls  5110  with a mounting slot  5300  designed to fit the bite trigger assembly within. One of the side walls may include a bite trigger assembly mating feature  5400  to mate with the bite trigger assembly&#39;s storage assembly mating feature  3600 . The bite trigger assembly mating feature  5400  may be formed from a geometry suitable for mating such as a dove tail joint (with the opposite mating dove tail joint included in the bite trigger assembly), fabric hook-and-loop fastener (with the opposite mating hook-and-loop fastener included on the bite trigger assembly), or a magnetic faster (with the opposite mating magnet included on the bite trigger assembly). 
     The storage assembly  5000  also includes a firearm mounting feature  5100  designed to enable the mounting feature to attach to the firearm. For example the firearm&#39;s forward grip  1620  may be replaced with the storage assembly  5000  using the appropriate type of mating fastener required to mate with the firearm, such as a threaded post on the storage assembly that screws into the mating threaded slot on the firearm. The storage assembly  5000  may also be attached to firearm accessory mounts such as a Picatinny rail, MIL-STD-1913 rail, STANAG 2324 rail, Weaver rail, or tactical rail, which are brackets used on some firearms to provide a standardized mounting platform for accessories and attachments. 
     The invention enables the operator  1100  to activate the firearm&#39;s trigger  1610  by biting down on the bite trigger assembly  1300 . Biting on the bite trigger assembly  1300  causes the cable assembly  1700  to be pulled, which in turn pulls the actuator  2200  within the actuator assembly  1200  enough to activate the firearm&#39;s trigger  1610 . When the operator  1100  stops biting on the bite trigger assembly  1300 , the actuator assembly&#39;s spring  2300  pushes the actuator  2200  back to the static position. In the static position, the actuator  2200  does not exert enough force to activate the firearm&#39;s trigger  2500 . The operator  1100  can repeat the process repeatedly to continue activating the firearm&#39;s trigger  2500  to discharge the firearm  1600 . When the operator  1100  is not intending to activate the firearm&#39;s trigger  1610 , the operator  1100  can stow the bite trigger assembly  4500  on the lanyard assembly  4000  (as shown in  FIG. 4 ). And when the operator  1100  is again ready to activate the firearm&#39;s trigger  1610 , the operator  1100  can easily retrieve the bite trigger assembly  1300  from the lanyard assembly  1400 . The operator  1100  can stow the bite trigger assembly  1300  within the storage assembly  1500  when the firearm  1600  is placed in storage. The invention is also designed to attach to an existing firearm, and the design of the invention may be standardized to fit on many different firearm types. 
     The terms and expressions, which have been employed herein, are used as terms of description and not of limitation, and there is no intention, in the use of such terms and expressions, of excluding any equivalents of the features shown and described (or portions thereof), and it is recognized that various modifications are possible within the scope of the claims. Other modifications, variations, and alternatives are also possible. Accordingly, the claims are intended to cover all such equivalents.