with reference to the attached drawings , four series , respectively a first 10 ( fig1 ), a second 110 ( fig2 ), a third 210 ( fig3 ) and a fourth 310 ( fig4 ) of sports shoes 11 , 111 , 211 and 311 , of variable size , are shown schematically . in general , in all the series 10 , 110 , 210 and 310 according to the present invention each ski boot 11 , 111 , 211 and 311 comprises a respective casing 12 , 112 , 212 and 312 of a different size for each series 10 , 110 , 210 and 310 and with which a sole 13 , 113 , 213 and 313 is associated underneath , of a fixed length for each series 10 , 110 , 210 and 310 . moreover , each ski boot 11 , 111 , 211 and 311 comprises inside it an inner boot 15 , 115 , 215 and 315 , able only to make the ski boot 11 , 111 , 211 and 311 more comfortable for the user to put on and wear . with particular reference to fig1 , a first series 10 is shown in which the boots 11 all have a sole 13 of fixed length l 1 , for example comprised between about 285 mm and about 290 mm , advantageously 288 mm . in this first series 10 , on three soles 13 of equal length , three respective distinct casings 12 are provided , each shaped in a different way from the others , so as to define respective three internal compartments 12 a , 12 b and 12 c , of a different size , variable in a discrete manner ( half a size , a size or a desired fraction of a size ), into which the specific inner boot 15 is inserted . in this case , the internal compartment 12 a has a usable internal length of about 235 mm , that is , about size 36 or 36½ european , the internal compartment 12 b has a usable internal length of about 245 mm , that is , about size 37½ , 38 , while the internal compartment 12 c has a usable internal length of about 255 mm , that is , about size 39 , 39½ . with particular reference to fig2 , a second series 110 is shown in which the boots 111 all have a sole 113 with a fixed length l 2 , for example comprised between about 315 mm and about 320 mm , advantageously 318 mm . in this second series 110 , on three soles 113 of equal length , three respective distinct casings 112 are provided , each shaped in a different way from the others , so as to define respective three internal compartments 112 a , 112 b and 112 c , variable in a discrete manner , of a different size , into which the specific inner boot 115 is inserted . in this case , the internal compartment 112 a has a usable internal length of about 265 mm , that is , about size 40 , 41 , the internal compartment 112 b has a usable internal length of about 275 mm , that is , about size 42 , 42½ , while the internal compartment 112 c has a usable internal length of about 285 mm , that is , about size 43 , 44 . with particular reference to fig3 , a third series 210 is shown in which the boots 211 all have a sole 213 with a fixed length l 3 , for example comprised between about 340 mm and about 350 mm , advantageously 348 mm . in this third series 210 , on three soles 213 of equal length , three respective distinct casings 212 are provided , each shaped in a different way from the others , so as to define respective three internal compartments 212 a , 212 b and 212 c , variable in a discrete manner , of a different size , into which the specific inner boot 215 is inserted . in this case , the internal compartment 212 a has a usable internal length of about 295 mm , that is , about size 45 , 45½ , the internal compartment 212 b has a usable internal length of about 305 mm , that is , about size 46½ , 47 , while the internal compartment 212 c has a usable internal length of about 315 mm , that is , about size 48 , 48½ . with particular reference to fig4 , a fourth series 310 is shown in which the boots 311 all have a sole 313 with a fixed length l 4 , for example comprised between about 375 mm and about 380 mm , advantageously 378 mm . in this fourth series 310 , on three soles 313 of equal length , three respective distinct casings 312 are provided , each shaped in a different way from the others , so as to define respective three internal compartments 312 a , 312 b and 312 c , variable in a discrete manner , of a different size , into which the specific inner boot 315 is inserted . in this case , the internal compartment 312 a has a usable internal length of about 325 mm , that is , about size 49 , 49½ , the internal compartment 312 b has a usable internal length of about 335 mm , that is , about size 50 , 50½ , while the internal compartment 312 c has a usable internal length of about 345 mm , that is , about size 51 , 51½ . in this way , by combining together the four series 10 , 110 , 210 and 310 made according to one embodiment of the present invention , it is possible to cover , with only four different lengths l 1 , l 2 , l 3 and l 4 of soles 13 , 113 , 213 and 313 , a number of foot sizes that goes from 36 to 51½ . the boots 11 , 111 , 211 and 311 of each of the series 10 , 110 , 210 and 310 described above are made by pressure die - casting of polymer material . in one embodiment , the molding equipment , not shown , has a first part substantially the same for all the boots 11 , 111 , 211 and 311 of the same series 10 , 110 , 210 and 310 and has pre - determined size . in this first part the sole 13 , 113 , 213 and 313 of each ski boot 11 , 111 , 211 and 311 is made . in this embodiment , the molding equipment also comprises a second part , modified or selectively modifiable in a front segment and / or in a rear segment thereof , for each boot 11 , 111 , 211 and 311 of the same series 10 , 110 , 210 and 310 so as to make different casings 12 , 112 , 212 and 312 for each series 10 , 110 , 210 and 310 . as shown schematically by a line of dashes in the attached drawings , the variation in thickness and / or inclination of the tip of the casing 12 , 112 , 212 and 312 and / or the variation in thickness and / or inclination in the heel part of the same determines the discrete variation of the relative internal volume 12 a , 12 b , 12 c ; 112 a , 112 b , 112 c ; 212 a , 212 b , 212 c ; 312 a , 312 b , 312 c , of the casings 12 , 112 , 212 and 312 and hence of the foot size of the boot 11 , 111 , 211 and 311 . according to an alternative embodiment , a specific mold is made for each boot 11 , 111 , 211 and 311 to be made . in this embodiment , the second part is shaped specifically to define the relative internal volume 12 a , 12 b , 12 c ; 112 a , 112 b , 112 c ; 212 a , 212 b , 212 c ; 312 a , 312 b , 312 c , of the casings 12 , 112 , 212 and 312 . according to another alternative embodiment , a single mold is made , at least one for each series 10 , 110 , 210 and 310 . in this solution , the second part of the mold is selectively modifiable by suitably positioning inserts , thicknesses , blocks or other , in the front segment and / or rear segment of the mold , so as to define , on each occasion , a desired internal volume 12 a , 12 b , 12 c ; 112 a , 112 b , 112 c ; 212 a , 212 b , 212 c ; 312 a , 312 b , 312 c , of the casings 12 , 112 , 212 and 312 . in this way , whether distinct molds are used for every boot 11 , 111 , 211 and 311 , or whether the same modifiable mold is used for each series 10 , 110 , 210 and 310 , we have the advantage of being able to provide the common production of at least a part of the mold for all the boots 11 , 111 , 211 and 311 of the same series 10 , 110 , 210 and 310 . it is clear , however , that modifications and / or additions of parts may be made to the series 10 , 110 , 210 and 310 as described heretofore , without departing from the field and scope of the present invention . for example , it comes within the field of the present invention to provide that there is a different number of series 10 , 110 , 210 and 310 other than four , and also that each series 10 , 110 , 210 and 310 provides a different number of boots 11 , 111 , 211 and 311 , other than three , between one series and the other . for example , it comes within the field of the present invention to provide a combination of five series of sports shoes , in which the first series comprises two boots , the second series comprises four boots , the third series comprises three boots and the fourth and fifth series each comprises two boots of different sizes . it is also clear that , although the present invention has been described with reference to specific examples , a person of skill in the art shall certainly be able to achieve many other equivalent forms of series of sports shoes , such as ski boots , snowboard boots or suchlike , of different sizes , and relative production method , having the characteristics as set forth in the claims and hence all coming within the field of protection defined thereby .
series , combination of series and method to produce sports shoes of different size , in which each sports shoe of different size comprises a casing substantially rigid and defining an internal compartment for containing the user &# 39 ; s foot , a sole associated below the casing and an inner boot disposed in the internal compartment , in order to make putting the foot into the casing more comfortable . the sole has always the same length for all the sports shoes , and the casing has a different size to each other so as to define , on each occasion , an internal compartment with a different volume for each of the sports shoes of different size , so as to cover a plurality of foot sizes , within a determinate range , keeping the length of the sole always the same .