Shock attenuation tension mounting for face guard
BACKGROUND OF THE INVENTION 
     U.S. Pat. No. 4,633,531 to Nimmons discloses a tension mounted face guard on a football helmet wherein a pair of resilient straps in the form of loop enclose wire segments of the face guard, the straps being secured to the vertical side portions of the helmet by suitable fasteners, whereby most of the shock force encountered by the face guard due to blows thereon is absorbed by the tension mounted straps. 
     Tests performed, in accordance with standards specified by the National Operating Committee on Standards for Athletic Equipment (NOCSAE), on face guards secured to the helmet by the single strap side connectors of the type disclosed in the abovementioned Nimmons patent, showed that the faceguard may contact the wearer&#39;s face due to either of two faults; namely, 
     (1) Excessive softness or resilience of the strap permits movement of the faceguard into the face. 
     (2) Excessive stiffness or rigidity of the strap transmits high impact force to the helmet causing it to rotate on the wearer&#39;s head resulting in facial contact with the faceguard. 
     Therefore, from the tests, it was determined that a single component strap selected for one extreme of compact blows will fail to provide suitable protection over the entire range of impact blows. 
     After considerable research and experimentation, the shock attentuation tension mounting of the present invention has been devised as an improvement on the tension mounting of the type disclosed in the aforementioned Nimmons patent, and comprises, essentially, a pair of looped straps on each side of the helmet, wherein an outer, relatively stiff looped strap encloses an inner, relatively stretchable looped strap which encloses wire segments of the face guard, the pair of looped straps being secured to the side portions of the helment by suitable fasteners. 
     By this construction and arrangement, the inner strap allows controlled movement of the faceguard toward the helmet with increasing resistance force for shock attenuation, and the outer strap limits the movement of the faceguard toward the helmet and resists breakage at maximum impact force from a frontal blow, the amount of movement being controlled by the selection of relative loop lengths of the outer and inner straps. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a perspective view of the shock attenuation tension mounting of the present invention securing a faceguard to the vertical side portions of a helmet; 
     FIG. 2 is a side elevational view of the mounting shown in FIG. 1; 
     FIG. 3 is a view taken along line 3--3 of FIG. 2; 
     FIG. 4 is a side elevational view of the outer looped strap employed in the mounting of the present invention; 
     FIG. 5 is a plan view of the inner strap prior to being bent to looped form; 
     FIG. 6 is a side elevational view of the strap shown in FIG. 5; 
     FIG. 7 is a graph illustrating the effect of an impact of 100 units of energy, such as 100 lb.-ft., delivered frontally to a faceguard employing an excessive rigid or stiff strap connection resulting in a peak force being transmitted to the helmet and wearer&#39;s head and neck over a short stretch distance of the strap; 
     FIG. 8 is a graph similar to the graph of FIG. 7 but wherein an excessive soft or resilient strap is employed in the faceguard connection; 
     FIG. 9 is a graph of the peak force being transmitted to the helmet over the stretch distance employing the shock attenuation mounting of the present invention; and 
     FIG. 10 is a graph similar to FIG. 9 wherein the inner loop is preloaded or pretensioned. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Referring to the drawings and more particularly to FIGS. 1 and 2, a football helmet 1 is provided with a conventional faceguard 2 secured to the top frontal edge portion 3 of the helmet by conventional mounting members 4, and to the vertical side ports 5 of the helmet by the shock attentuation tension mounting 6 of the present invention. 
     The details of the tension mounting 6 are illustrated in FIGS. 3 to 6, wherein it will be seen that a length of stretchable, resilient material 7 is provided having a planar lower surface 7a, a relatively thin medial portion 7b between relatively thick end portions 7c having apertures 7d provided therein. As will be seen in FIG. 3, the length of stretchable material 7 provides a strap adapted to be bent back on itself to form a loop enclosing a wire segment 2a of the faceguard. 
     Referring to FIG. 4, a plastic relatively stiff strap is molded to form a loop member 8 having spaced, parallel legs 8a, 8b. The end of leg 8a is provided with a thick portion 8c which forms a shoulder 8d adjacent the end of the leg 8a. The thick portion 8c is provided with an aperture 8e aligned with a similar aperture 8f provided on the end of leg 8b, the aperture 8e also being counter-bored as at 8g. 
     To assemble the mounting 6 on the helmet, as shown in FIG. 3, a washer 9 is placed against the interior wall of the side portion 5 of the helment with its aperture 9a aligned with an aperture 5a provided in the helmet side portion. A tee-nut 10 having an extended shank portion 10a is inserted through the aligned apertures 9a and 5a. The loop member 8 is then connected to the tee-nut 10 by inserting the tee-nut through the aperture 8f on leg 8b. The outer leg 8a of the loop member 8 is temporarily bent outwardly so that one end 7c of the strap 7 forming the inner loop can be connected to the tee-nut 10 by aligning the aperture 7d with the tee-nut shank 10a and then sliding the end 7c thereon. The strap 7 is then wrapped around the wire segment 2a of the faceguard and bent back upon itself so that the opposite end of the strap can be slid onto the shank 10a of the tee-nut. The planar lower surface 7a at each end of the strap is now in face-to-face relationship. The outer leg 98a is then bent inwardly whereby the end of tee shank 10a is inserted into the aperture 8e of the outer loop 8. The entire assembly is then secured to the helmet by inserting a bolt 11 into the tee-nut 10. By tightening the bolt 11, the shoulder 8d engages the relatively thin portion 7b of the inner loop 7, to thereby force the inner loop 7 and faceguard wire segment 2a into a preload or tensioned position. 
     By the construction and arrangement of the tension mounting 6 of the present invention, the relatively resilient inner loop 7 allows movement of the faceguard 2 toward the helment 1 with increasing resistance force for shock attenuation, and the relatively stiff outer loop 8 limits the movement of the faceguard toward the helmet, the amount of movement being controlled by the selection of relative loop lengths of the outer and inner straps 8 and 7, respectively. 
     The shoulder 8d on the outer strap 8 engaging the inner strap 7 initially properly positions the faceguard on the helment, and by tightening the bolt 11, the shoulder 8d causes the inner strap 7 to stretch beyond its initial position to thereby preload or pretension the mounting 6. The preloading not only provides the advantage of reducing the peak transmitted force over a wide range of impacts but also eliminates looseness or rattle of the faceguard caused by dimensional fit requirements or by residual stretch from repeated impact. 
     The graphical representation shown in FIGS. 7 to 10 illustrate the effect of an impact delivered frontally to a faceguard secured to the helment by various attachments. FIG. 7 represents a faceguard employing an excessive stiff attachment, wherein movement of the faceguard is stopped within 1 unit of distance but a peak force of 2 units is delivered to the wearer&#39;s head. 
     FIG. 8 represents a faceguard employing such an excessive resilient attachment that the attachment stretches so far that the faceguard impacts on the chin. The attachment stretches approximately 3 units of distance and transmits 2 units of force to the wearer&#39;s head when the faceguard impacts on the chin. 
     FIG. 9 represents the shock attenuation tension mounting of the present invention wherein the inner loop 7 allows movement of the faceguard 2 toward the helmet 1 with increasing resistance force, the stretching of the inner loop 7 being limited by the outer loop 8, to thereby stop movement of the faceguard in 2 units of distance and transmitting 1.5 units of peak force to the wearer&#39;s head. 
     FIG. 10 represents the mounting of FIG. 9 wherein the inner strap 7 is preloaded whereby approximately 1.2 units of peak force is transmitted to the wearer&#39;s head in 2 units of distance. 
     From the above description, it will be appreciated by those skilled in the art that the shock attenuation mounting of the present invention reduces the amount of high peak forces delivered to the head than provided heretofore by known attachments or mountings, to hereby reduce the instances of concussion, neck injury, or displacement of the helment and facial contact with the faceguard. 
     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 ue of such terms and expressions, of excluding any equivalents of the features shown and described or portions thereof but is is recognized that various modifications are possible within the scope of the invention claimed, including utilizing the inner looped strap in both pretensioned and untensioned states.