Abstract:
A helmet retention system including a forwardly facing helmet comprises, 
     A. left and right side retention strap sections, the left section having attachments to the helmet at forward and rearward locations, and the right section having attachments to the helmet at forward and rearward locations, the sections hanging from the helmet, 
     B. left and right sliders respectively slidably attached to the left and right retention straps to be adjustably slidable therealong, and 
     C. chin strap means having attachment to and hanging from the sliders to extend therebetween.

Description:
BACKGROUND OF THE INVENTION 
     This invention relates generally to adjustable retention of helmets, as for example are used by bicycle or motorcycle riders; more particularly, it concerns a very simple retention system employing few parts and providing for universal adjustment of the helmet on the wearer&#39;s head. The invention is especially adapted for use with lightweight, plastic helmets as will be described. 
     SUMMARY OF THE INVENTION 
     It is a major object of the invention to provide an unusually advantageous helmet retention system that basically comprises: 
     A. left and right side retention strap sections, the left section having attachments to the helmet at forward and rearward locations, and the right section having attachments to the helmet at forward and rearward locations, the sections hanging from the helmet, 
     B. left and right sliders respectively slidably attached to the left and right retention straps to be adjustably slidable therealong, and 
     C. chin strap means having attachment to and hanging from the sliders to extend therebetween. 
     As will appear, the sliders may comprise like plates containing forward and rearward slits for passing the left and right retention strap sections, and vertically spaced horizontal slits to pass looping portions of the chin strap sections; the left and right retention strap sections may comprise a single strap attached to the rear of the helmet via angled slits in the helmet, and adjustably attached to the left and right sides of the helmet via additional slits. Further, the chin strap means typically includes primary and secondary sections adjustably interconnected via D-rings as will be described, the sliders supporting those sections. 
     As a result, the sliders may be adjustably shifted along the left and right retention strap sections to control forward or rearward tilting of the helmet; the closeness of the sliders to the wearer&#39;s ear may be adjusted by adjusting the attachments of the retention strap sections to the helmet; and the tightness of the chin strap means may also be adjusted. 
     These and other objects and advantages of the invention, as well as the details of an illustrative embodiment, will be more fully understood from the following description and drawings, in which: 
    
    
     DRAWING DESCRIPTION 
     FIG. 1 is a side elevation of a helmet and retention system; 
     FIG. 2 is an enlarged side elevation of a slider and associated strap; 
     FIG. 2a is a vertical section on lines 2a--2a of FIG. 2; 
     FIG. 3 is a side elevation of the slider seen in FIG. 2; 
     FIG. 4 is a view like FIG. 3 showing a retention strap section passing through slits in the slider; 
     FIG. 5 is an elevation on lines 5--5 of FIG. 1, showing anchorage of the retention strap to a rear portion of the helmet; 
     FIG. 6 is an enlarged vertical section through a side portion of the helmet, and looking rearwardly, to illustrate left retention strap section attachment to the helmet; 
     FIG. 7 is a vertical elevation showing chin strap sections in relation to D-rings; and 
     FIGS. 8-12 are side elevations showing different positions of the helmet on the wearer&#39;s head. 
    
    
     DETAILED DESCRIPTION 
     In FIGS. 1, 5 and 9 the system shown includes left and right retention strap sections 10 and 11, the left sections having attachments to the helmet 12 at forward and rearward locations 13 and 14, and the right section having attachments to the helmet at forward and rearward locations 15 and 14. Note that the sections both hang from the helmet, the forward locations 13 and 15 being located about 1/4 to 1/3 of the way from the front to the rear, and that the rearward locations 14 are common or near one another. The sections 10 and 11 may consist of one continuous strap passing through upwardly tapering slits 16 and 17 in the rearwardmost portion of the helmet shell 12a. The sections merge at 18 at the outer side of the shell, whereby they pass downwardly at the inner side of the shell 12a rim bead 12b, as is clear from FIG. 5, and cross below the bead. 
     Left and right sliders, as at 20, are respectively slidably attached to the left and right retention straps to be adjustably slidable therealong; in addition, chin strap means, generally indicated at 21, has attachment to the sliders and hangs therefrom as seen in FIG. 1. Each slider may, with unusual advantage, take the form of a plate containing forward and rearward slits for passing a retention strap section. As seen in FIGS. 2-4, the upright plate 22 contains forward and rearward slit 23 and 24 which are upwardly convergent, for directing the left retention strap sections in V-shape configuration beyond the slider edges 25 and 26, as shown. Note that section 10 extends at 10a at the outer side of the plate. Each slider plate also contains upper, middle and lower generally horizontal slits 30, 30a and 31 for passing a looping portion of the chin strap means. In FIGS. 2, 2a and 7, the left section 21a of the chin strap means extends upwardly, and outwardly through lower slit 31 as two overlapping portions 21a&#39; and 21a&#34;; portion 21a&#39; extends back through slit 30a and then upwardly and through upper slit 30 to merge with portion 21a&#34; at the outer side of the slider. The portion 21a&#34; overlaps portion 10a of section 10, at the outer side of the plate, as seen in FIG. 2a, tending to frictionally hold the portion 10a clamped against the plate, during usage. The edges of slits 23 and 24 also tend to position the slider lengthwise of the retention strap 10. The other section 21b of the chin strap means may be similarly retained by the slider associated with retention strap 11. 
     Referring to FIGS. 2 and 7, two D-rings 35 and 36 are provided and suspended by a looping portion 37 of the chin strap means. Portion 37 may be integral with section 21a, as described above. The secondary section 21b of the chin strap means laces through the first ring 35 and then through the second ring 36; it then loops about the outer side of a lateral leg 36a of ring 36, at locus 21b&#39;, and then extends at 21b&#34; back through the first D-ring 35 adjacent and at the inner side of its lateral leg 35a. When chin strap end 21b&#39;&#34; is pulled tight, the chin strap tightens against the wearer&#39;s chin or jaw, and the strap 21b is retained by the clamping action of the D-rings. A pull-tab 38 integral with ring 35 may be pulled to the right in FIG. 7 to loosen the chin strap means. 
     Referring now to FIG. 6, the forward attachment at 13 and 15 advantageously include vertically spaced perforations in the left and right side of the typically plastic helmet, and through which the left and right retention strap sections extend, respectively. FIG. 6 which looks rearwardly at the left retention strap section attachment, illustrates the provision of three vertically spaced, horizontally extending, perforations 40, 41 and 42 through the helmet shell 12a. The left retention strap section 10 extends upwardly into the shell between bead 43 and inner cushion 44, then outwardly through lower slit 42, then upwardly at 10&#39; to enter inwardly via slit 40 into the helmet, then downwardly at 10&#34; between the shell and cushion 44, then back outwardly through middle slit 41, then downwardly at 10&#39;&#34;, and then back inwardly through lower slit 42 to terminate at 10&#34;&#34;. Accordingly, a looping configuration is formed, which is loosenable and adjustable to adjust the chin strap means. Thus, to raise the adjusting plates, the strap extent 10&#39; is pulled outwardly to enlarge the loop as seen in FIG. 9 and inner strap extent 10&#34;&#34; is pulled downwardly; this procedure is carried out at both attachment locations 13 and 15 using both straps 10 and 11. Reversal of this procedure lowers the plates and the chin strap. The plates 22 should fit just below the ears as in FIG. 8. 
     The helmet 10 should sit level on the wearer&#39;s head, as in FIG. 11. If the helmet is tilted too far down in front, as in FIG. 10, obstructing vision, the sliders 20 are moved rearwardly on the straps 10 and 11. If the helmet is tilted too far to the rear as in FIG. 12, the sliders may be moved forwardly on straps 10 and 11 until the helmet seats properly as in FIG. 11. 
     Note that very simple construction and unusual adjustment of the helmet is provided for, as enabled by the sliders and their relationship to the retention and chin straps, and by adjustment of the straps as described. 
     Merely as illustrative, the outer helmet 12a may consist of LEXAN, and the inner cushion 44 of polystyrene.