the skate shown in fig1 includes a frame 1 with a u - shaped transverse section having two lateral flanges 2 on which the wheels 4 are affixed . the skate also includes a boot 5 which is attached with respect to the frame through its sole 6 at both the heel and the toe areas . for the heel area , a mounting plate 3 is shown . the boot 5 has the external appearance of a normal low boot and , therefore , includes a low flexible upper 10 , i . e ., an upper whose rigid portions do not extend upwardly beyond the malleoli , provided on its front portion with an opening 11 for passage of the foot and with a lacing system 20 of a known type , for closing the boot and tightening the foot . the upper 10 is provided in the heel area with a rigid rear stiffener 12 , which can be made in any known manner , and in fact constitutes the only rigid portion of the upper . this stiffener 12 is preferably made of a rigid synthetic material , and extends over the entire rear portion of the boot , around the heel thereof . this stiffener 12 extends , in the malleoli area , up to the top of the upper , for receiving a journalled collar 13 , and externally has at the level of the malleoli a boss 12a projecting outwardly and extending substantially perpendicular to the wall of the stiffener . each boss 12a is further provided with a hole 12b for the journalled mounting of the collar 13 by means of studs 19 ( see fig4 ). these studs 19 serve to stop the collar 13 , whereas the bosses 12a define the axis of rotation 30 of this collar on the upper . the studs 19 can be replaced by any other connection means allowing a rotation , such as rivets . however , the use of studs 19 is particularly advantageous because it allows for a mounting by merely applying pressure , without requiring a counter - element as is the case with rivets , which makes it possible to considerably simplify the manufacturing , since the collar can then be mounted during the last step of the boot manufacturing . furthermore , the studs 19 will be advantageously constituted of a relatively flexible material with respect to a metal rivet , such as delrin , so that their heads 19a follow the possible deformations of the rigid collar 13 , for example , when a torsion of the leg occurs , such a construction making it possible to avoid the pulling of these nails during such a torsion . the journalled collar 13 could also be mounted according in another manner , by allowing for easy disassembly , and for example by means of bayonet or ratchet systems , which are known and not described hereinafter , for setting the collar or using the boot with a simple low upper . in the illustrated embodiment , the journalled collar 13 is in the form of a cuff made of a rigid material and especially a synthetic material such as pebax . this collar 13 extends upwardly up to the base of the calf and surrounds the entire lower part of the leg . it is opened at its front portion to allow the positioning of the foot in the boot , and is provided with known tightening arrangement 15 and , for example , is constituted by auto - gripping means . furthermore , this collar 13 is provided at the rear with a scallop 13a adapted to facilitate the rearward rotation of this collar ( see position in dotted lines in fig1 ). as it will be easily understood , the substantial height of the collar 13 allows for an excellent lateral leg retention when skating , such a height further enabling a greater distribution of the reaction forces on the leg and , consequently , a better comfort for the user . however , such height for the collar 13 does not hinder the rear / front flexional movements of the leg with respect to the foot , and can even be increased , for example , up to mid - leg so as to decrease the forces on the leg . indeed , the total and independent journal of the collar 13 on the upper enables the latter one to pivot freely , with no flexional limitation by the upper and with no hindrance for the user . in fact , the tongue 22 of the boot does not extend upwardly beyond the flexional fold of the foot of the user so as not to hinder the flexion thereof , nor the pivoting of the collar . surprisingly , such a freedom in the motion of the ankle has proved not to be detrimental to the lateral holding of the ankle to perform this type of skating , while offering a clearly improved comfort and with no hard spot with respect to the conventional skate boots . moreover , the flexible structure of the upper of the boot , preferably made of an aerated textile material , allows to avoid perspiration problems related to the use of &# 34 ; non - breathable &# 34 ; plastic materials , and therefore offers a double comfort , with respect to both the aeration and the tightening of the foot obtained by means of flexible portions . in such a construction , the very rigid sole 6 also contributes to the foot retention . to further increase the comfort of such skate , and as shown in fig2 the collar 13 is provided internally with a lining 16 intended for the comfort of the leg and interrupted in the area 13a for covering the lower portion of the collar 13 and the upper portion 10a of the upper 10 , so as to avoid any excessive thickness in this area . the comfort portion of the collar is &# 34 ; borne &# 34 ; thereon so that its pivoting can not be disturbed by a comfort portion originating from the upper . in the case shown , the extreme upper portion 10a of the upper extends in fact slightly above the rear stiffener 12 , and therefore above the malleoli , to ensure a continuity of the upper / collar , but such a construction is not a hinderance since this portion 10a is not rigid and is intended only for the comfort . therefore , such a portion 10a does not at all disturb the flexion of the leg and could be eliminated as well . for comfort purposes , the lining 16 is designed so as to extend in the extension of the internal surface of the upper . fig4 shows a skate similar to that of fig1 and for which the same elements will be designated by the same reference numerals . the only differences between this skate and that previously shown reside in the provision on the boot of a cover 17 and of a return device or element 25 of the collar . as shown in this fig4 the cover 17 is constituted of two portions 17a , 17b extending over the top of the upper by covering the lacing system , and over the front of the lower part of the leg , respectively , so as to block the opening defined by the collar 13 , for sealing purposes . these two cover portions , 17a , 17b are connected to one another by a seam 18 forming a hinge so as to maintain the flexibility of the boot and not to disturb the pivoting of the collar , the cover portion 17b being capable of pivoting with respect to the cover portion 17a affixedly with the collar . as shown in fig4 the cover portion 17a can , in a known manner , be opened in two portions by means of a zip fastener 21 to allow access to the lacing system 20 of the boot . the return element or device 25 of the collar 13 is , in the example shown , made of a double pin having two arms , one upper arm 26 in support against the lower edge 13b of the collar , and one lower arm 27 in support against an associated abutment surface 31 of the rear stiffener 12 of the upper . furthermore , the element 25 passes around the journal axis 19 of the collar to be maintained in place . this elastic return device 25 has an active phase , i . e ., it is biased , during a rearward pivoting of the collar from a substantially vertical median equilibrium position thereof , which is defined by the axis o - o &# 39 ; in fig4 and thus exerts , during such a pivoting of the collar , a force for returning this collar frontwardly . consequently , the frontward pivoting of the collar is completely free , i . e ., the elastic return device 25 has an inactive phase , whereas its rearward pivoting occurs against the elastic element 25 which conversely facilitates the frontward return of the collar . the elastic return element 25 could be made in a totally different manner , the essential purpose being that it exerts a return force on the collar during the rearward pivoting thereof . for example , it could be a spring of a different type , such as a coil spring , elastic buffer , . . . etc . this elastic element could also be designed to be integral with one of the elements of the upper and , as shown in fig5 the elastic return element could thus be constituted by an elastic arm 25a extending from the journalled collar 13 and cooperating with an abutment provided on the rear stiffener , or another portion of the upper 10 . conversely , it could also be an elastic arm extending from the rear stiffener of the upper and cooperating with an associated abutment of the collar . in any event , such an arrangement tends to help the muscle of the leg which controls the lifting of the tip of the foot with respect to the leg , and therefore makes it possible to limit the fatigue thereof during the sport activity . another important advantage of this elastic return element is that it provides the leg of the athlete with a sort of rear support with a progressive resistance , and especially that it provides the latter with a rearward referencing of the position of his or her leg , i . e ., it allows the athlete to locate the position of the leg with respect to the vertical , a very important item of information for maintaining the balance in such a gliding sport . the present invention is not limited to the examples of embodiment described hereinabove , but also encompasses any similar or equivalent embodiments .
a roller skate having a boot provided with a rear stiffener and including a rigid collar journaled on the rear stiffener and adapted to surround the lower part of the leg . the upper of the boot is a low upper and the journal of the rigid collar on the upper is located in the area of the upper end thereof , and substantially in the area of the malleoli .