Patent Application
20080141798
The present invention relates generally to a stored energy trigger design and more particularly to a stored energy trigger design with controlled activation distance implementation.
Triggers are utilized in a wide variety of mechanical structures. In many industries, such as in automotive design and manufacture, they are utilized to activate additional mechanical components. In one such application, a trigger is utilized to release an automotive seat back such that it may be folded down. These triggers commonly have two essential characteristics. The first is simple and reliable activation. The second is the ability to be mechanically reset after activation.
Often such trigger assemblies require considerable number of active components in order to ensure proper and consistent operation. Gearing and bearing usage additionally is common. The additional complexity carries with it additional warranty concerns in addition to reductions in operational life-span. In addition, often these systems utilize rigid connections between the trigger assembly and the activation components. These rigid connections require tight tolerances and may result in increased wear.
It would be highly desirable to have simple and reliable trigger assembly that would release stored energy into an activation element. In addition, it would be highly desirable to have such a simple and reliable trigger assembly that utilized semi-rigid activation assemblies such as push-wire assemblies.
In accordance with the objects of the present invention a stored energy trigger assembly is provided including a mounting substrate and a pawl plate rotationally mounted thereto having a pawl mount end, a pawl trigger end, and a pawl lock protrusion positioned between. The pawl plate rotatable between a pawl lock position and a pawl disengage position to which it is biased. A cam plate is rotationally engaged to the mounting substrate and includes a cam plate upper surface, a earn plate lower surface, a cam lock slot, and a push wire engagement protrusion positioned on a cam plate periphery. It is rotatable between a cam lock position and a cam release position to which it is biased. A pawl trigger element engages the pawl trigger end and is configured to move the pawl plate to the pawl disengage position. A push wire assembly is moved a wire activation distance when the cam plate is moved to the cam release position. The pawl lock protrusion is positioned within the cam lock slot and restrains the cam plate until the pawl trigger element moves the pawl plate into the pawl disengage position wherein the pawl lock protrusion moves out of the cam lock slot and the cam plate is free to move into the cam release position.
Other objects and features of the present invention will become apparent when viewed in light of the detailed description and preferred embodiment when taken in conjunction with the attached drawings and claims.
Referring now to
The stored energy trigger assembly 10 includes a mounting substrate 12 which may be formed independently or in concert with structures in which the trigger assembly 10 is installed. A pawl plate 14 is rotatably engaged to the mounting substrate 12. Although variations of the pawl plate 14 are contemplated, in one embodiment, the paw plate 14 comprises an elongated pawl arm. The pawl plate 14 preferably includes a pawl mount end 16 and a pawl trigger end 18. A pawl lock protrusion 20 is positioned between the pawl mount end 16 and the pawl trigger end 18. Although the pawl plate 14 may rotatably engage the mounting substrate in a variety of fashions, one embodiment contemplates the use of a pawl rotational mount post 22 positioned within a pawl mount slot 24 formed in the mounting substrate 12. A pawl post slot 26 may be formed on the pawl plate 14 to house the pawl rotational mount post 22. The pawl plate 14, therein is rotatably secured to the mounting substrate 12.
A pawl trigger element 28 is engaged to the pawl trigger end 18 and is capable of rotating the pawl plate 14 between a pawl lock position 30 (see
An additional active element in the present invention is a circular cam plate 44 also rotationally engaged to the mounting substrate 12. The cam plate 44 is comprised of a cam plate upper surface 46, a cam plate lower surface 48, and a cam plate periphery 50. A cam lock slot 52 is formed on the cam plate periphery 50 and is configured to selectively engage the pawl lock protrusion 20. The cam plate 44 is rotatable between a cam lock position 54 and a cam release position 56. The cam plate 44 is biased towards the cam release position 56. When in the cam lock position 54 and the pawl plate 14 is in the pawl lock position 30, the pawl lock protrusion 20 engages the cam lock slot 52 and restrains the cam plate 44 from movement. Upon movement of the pawl plate 14 to the pawl disengage position 32, the cam plate 44 is free to follow its bias and move into the cam release position 56.
Although rotational mounting and biasing of the cam plate 50 could have been achieved in a variety of fashions, the present invention contemplates the use of a substrate mount post 58 engaged to the mounting substrate 12. The substrate mount post 58 protrudes upwards through a cam mount center axis slot 60 to allow rotational movement of the cam plate 44. In one embodiment, the substrate mount post 58 includes a semi-circular engagement body 62 configured to securely engage a semi-circular body slot 64 formed in the mounting substrate 12. The substrate mount post 58 further includes a spring slot 66 formed therein and protruding above the cam plate upper surface 46. A coil leaf spring 68 is positioned on the cam plate upper surface 46 and includes a center coil end 70 and an outer coil end 72. The center coil end 70 is preferably configured to reside in and securely engage the spring slot 66. The coil leaf spring 68 provides the bias to the cam plate 44.
The cam plate 44 further includes a push wire (activation element) engagement protrusion 74 formed on the cam plate periphery 50. A push wire (activation element) engagement post 76 is mounted within the push wire engagement protrusion 74 and extends both below the cam plate lower surface 48 as well as above the cam plate upper surface 46. A particular novel element of the present invention comprises a push wire (activation element) assembly 78 engaging the push wire engagement post 76. Push wires 78 are commonly comprised of a push wire cable 80 made up of a main push wire 82 slidably residing within a push wire housing 84. This allows the push wire assembly 78 to not only act as an activation element, but also to allow the push wire assembly 78 to push the cam plate 44 back into the cam lock position 54 after activation. In one example, the movement of a passenger seat back into an upright position would push on the push wire assembly 78 and resent the cam plate 44. Although the push wire cable 80 may be attached to the push wire engagement post 76 in a variety of fashions, one embodiment contemplates the use of a push wire post shell 86 that covers and engages the push wire engagement post 76. The push wire engagement post 76 is additionally utilized to engage the outer coil end 72 of the coil leaf spring 68.
An additional novel concept of the present invention involves a semi-circular activation distance control slot 88 formed in the mounting substrate 12. The push wire engagement post 76 protrudes downward and slidably resides within the activation distance control slot 88. This precisely controls the amount of rotation of the cam plate 44 and thereby provides precise control of the push wire (activation element) activation distance 90 (see
While the invention has been described in connection with one or more embodiments, it is to be understood that the specific mechanisms and techniques which have been described are merely illustrative of the principles of the invention, numerous modifications may be made to the methods and apparatus described without departing from the spirit and scope of the invention as defined by the appended claims.
