Abstract:
A lock device having a key and a lock cylinder. The lock cylinder includes a fixed cylinder housing and a cylinder core mounted to rotate therein. The key shaft ( 10.3 ) has an edge profile and may be inserted in a key way of the cylinder core in which displaceable tumblers ( 41, 42 ) are located transverse to the above. The key shaft ( 10.3 ) has profiled recesses running in the longitudinal direction. The recesses have a pair of follow points for each tumbler ( 41, 42 ) for coding the key, whilst the tumbler ( 41. 42 ) has a pair of counter follow points which are the basis of the corresponding counter coding. A space-saving design of the lock device is achieved with a large range of variation for the coding wherein both follow points are on the key shaft ( 10.3 ) in the form of recesses, arranged on opposing lateral surfaces to an edge ( 57.2; 57.3 ) of the edge profile of the key shaft ( 10.3 ). A web ( 22: 23 ) is thus generated in the corner region of the edge profile between both recesses. The web functions as a code web ( 22; 23 ), as the opposing web edges serve for the coding. The corresponding tumblers ( 41, 42 ) have a cut-out, which in use enclose the code web ( 22; 23 ) on opposing web edges. The lateral limits of the cut-out form the counter follow points in the tumblers ( 41, 42 ).

Description:
This application is a 371 of PCT/EP2006/008004 filed Aug. 12, 2006, which in turn claims the priority of DE 10 2005 042 618.2 filed Sep. 7, 2005, the priority of both applications is hereby claimed and both applications are incorporated by reference herein. 
     BACKGROUND OF THE INVENTION 
     The invention concerns a lock device. A lock device of this type is disclosed by DE 199 44 070 C2. In that lock device, the coding of the key consists of a coding groove that extends in the longitudinal direction of the key. The corresponding tumblers have projections to serve as scanning points, and, when the key is inserted, each of these projections fits into a certain cross section of the coding groove. The position of the projection on the tumbler depends on the coding of the groove and thus constitutes the corresponding countercoding of the lock device. 
     EP 0 267 316 A1 describes a different lock device, in which the bit of the key has a polygonal cross section. Notches of different depths are formed on the edges of the bit. Spring-loaded tumbler pins engage the edges of the key bit and scan the depth of the notches in the corner regions of the key bit. At the tip of the key bit, bevels are provided on the lateral surfaces between the edges to raise the tumbler pins when the key is inserted. 
     SUMMARY OF THE INVENTION 
     The objective of the invention is to find a reliable lock device with a new coding possibility. An important goal of the coding is to develop a key which has a small cross section but is nevertheless distinguished by a large range of variation of codings. 
     The invention creates the coding in the corner regions of the edge profile of the key bit. The pair of scanning points is produced by two recesses proceeding in opposite directions from each other in adjacent lateral surfaces of the edge profile. A web is left in the corner region of the edge profile between the two angular cutouts. In successive axial sections of the code web, opposite web flanks are offset from each other in pairs and produce the pairs of scanning points of the key bit, which in this way serve for coding. For this reason, this web can be called a “code web”. The course of the code web is determined by the corner region of the edge profile. Because the two web flanks of the code web can, if necessary, also extend beyond the edge of the edge profile of the key bit, we obtain, with a small key cross section, a large range of variation in the arrangement of the two opposite web flanks of the code web that serve for coding. Because the two web flanks are enclosed by the lateral boundaries of a cutout in the tumblers, positive guidance is provided. This positive guidance has an advantage in lock devices in which the key acts only as an emergency key and therefore is used only in exceptional cases. When a key is used only in emergencies, the tumblers in the cylinder core can become tight or sticky due to long disuse. The positive guidance of the invention ensures smooth movement of the tumblers. In an emergency key of this type, the lock device is normally controlled by electric remote control or by a smart card. 
     Because the edge profile of the key bit usually has several edges, e.g., it has a rectangular design, a code web of the invention can be located in each of the corner regions. At least some of these code webs can have a coding that differs from the others in order to realize a large range of variation of the lock device of the invention. 
     In addition, protection against being forced open is increased, because the cooperating scanning points of the tumblers engage different code webs and therefore can be displaced in different directions in the cylinder core relative to each other. This makes it more difficult for unauthorized persons to get a grasp of how the lock device can be forced open. This also makes it more difficult to use picking tools to decode the code. 
    
    
     
       The invention is explained below with reference to several specific embodiments illustrated in the drawings. 
         FIGS. 1   a  and  1   b  show perspective views of a first and a second embodiment of the key bit of the invention. 
         FIG. 2  is a schematic drawing of an enlarged corner region of the key bit shown in  FIG. 1   a  or  FIG. 1   b , where variants for the formation of a code web are illustrated before the recesses necessary for this are produced. 
         FIG. 3  shows a practical cross section through the key bit with a pair of scanning points, one on each side of the code web. 
         FIG. 4  shows a cross section through the lock device, which is analogous to the cross section shown in  FIG. 3 , and which shows, in addition to coding on the code web, the corresponding countercoding on an associated tumbler. 
         FIGS. 5   a  and  5   b  show top views of two specific embodiments of a practical tumbler, which is assigned to a specific pair of scanning points in the key of  FIGS. 1   a  and  1   b.    
         FIG. 6  shows a perspective view of a third specific embodiment of a key bit of the invention with two tumblers, which act on two code webs that are different from each other. 
         FIGS. 7   a  and  7   b  show two enlarged cross sections through the key bit shown in  FIG. 6  along the sectional planes VIIa-•-VIIa and VIIb-•-VIIb in  FIG. 6 . 
         FIG. 7   c  shows a cross section through a complete lock device of the invention with a lock cylinder and a key bit. 
         FIG. 8  shows a top view of the key bit already shown in  FIG. 6 . 
         FIGS. 9 and 10  show two cross sections through the key bit of  FIG. 8  along the sectional planes IX-•-IX and X-•-X. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       FIG. 1  shows a first embodiment  10 . 1  of a key bit, which has an edge profile  17 . This edge profile  17  has a rectangular design and has only one code web  21  in the area of one of the edges  57 . 1 . The perspective drawing shows two lateral surfaces  11 ,  12 . The rectangular profile has different edge dimensions, because the width  18  is greater than the profile height  19 . 
       FIG. 1   b  shows a second embodiment  10 . 2  of a key bit, whose edge profile  17  is also a rectangle, but in this case, all of the corner regions  30 . 1  to  30 . 4  are provided with code webs  21  to  24 , three of which ( 21 ,  22 ,  23 ) can be seen. The design of code webs of this type will be explained in greater detail with reference to  FIGS. 2 and 3 . 
       FIG. 2  shows, with omission of the shading, the cross section of a corner region  30 . 1  between two flat lateral surfaces  11 ,  12  of the key bit  10 . 2 . As illustrated in  FIG. 3  by point shading, a recess  31 ,  32 , which in the present case has an angular design, is cut into each lateral surface  11 ,  12 . Therefore, the two recesses will be referred to as angular recesses  31 ,  32 . The angular recesses  31 ,  32  have sides  34  that face each other, between which a web  21  is formed. The web flanks  25 . 1 ,  26 . 1  formed by the two angle sides  34  act as a pair of scanning points  15 ,  16  of the key bit  10 . 2 , whose lateral position serves as code. Therefore, the web  21  can be referred to as the “code web”. In the embodiment of  FIGS. 2 and 3 , the angular recesses  31 ,  32  are formed as right angles. 
     The keys  10 . 1 ,  10 . 2  described above are parts of a lock device, which also includes a lock cylinder  50 , which is shown in  FIG. 7   c .  FIG. 7   c  shows a cross section through a lock cylinder of this type, which consists of a stationary cylinder housing  51  and a cylinder core  52 , which is rotatably supported therein. The cylinder core  52  is provided with a keyway  53 , in which, in  FIG. 7   c , a third embodiment  10 . 3  of a key bit of the invention is inserted, which will be described in greater detail later in connection with  FIGS. 6 to 10 . The cylinder core  52  has chambers, in which spring-loaded tumblers  41  can move transversely to the key axis  27 . Springs  54  act on a projection  38  of each tumbler  41 . The linear movement of the tumblers  41  is illustrated by a double arrow  47 . 1  in  FIG. 7   c . If the key bit  10 . 3  were not inserted, the springs  54  would push the tumblers into blocking channels  55 . 1  or  55 . 2 , thereby holding the cylinder core  52  in place so that it cannot turn in the cylinder housing  51 . In the embodiment illustrated in  FIG. 7   c , the cylinder housing  51  has two additional blocking channels  56 . 1  and  56 . 2 , into which, when the key is pulled out, the ends of another tumbler  42  at right angles to the illustrated tumbler  41  can enter. This will be described in greater detail in connection with  FIGS. 6 and 7   a.    
       FIG. 4  shows in greater detail how a tumbler  41  of this type interacts with the inserted key bit  10 . 2 . The aforementioned pair of scanning points  15 ,  16  on the sides of the code web  21  engages a pair of cooperating scanning points, which constitute a corresponding countercoding. This occurs by means of a cutout in the tumbler. The code web  21  fits into this cutout when the key is inserted. The edges  43 ,  44  of the cutout  40  form the two cooperating scanning points  45 ,  46 . 
     As  FIG. 5   a  shows, the tumbler  41  has a plate-like design and has a central opening  39 , through which the key bit passes when the key is inserted. The cutout  40  borders on this central opening  39  and points in the same direction as the lateral projection  38 , described above in connection with  FIG. 7   c , on which the spring  54  acts. 
       FIG. 5   b  shows a tumbler  41 ′ that is an alternative to the tumbler  41  shown in  FIG. 5   a . The difference is that certain edges of the plate-like tumbler are beveled. The various beveled edges are labeled  48 . 1  to  48 . 5  in  FIG. 5   b . For example, first of all, beveled edges  48 . 1  and  48 . 2  are provided on the two aforementioned edges  43 ,  44  of the cutout  40 . These beveled edges  48 . 1 ,  48 . 2  allow the shaft of the key to be threaded more easily through the opening  39  when the key is inserted into the keyway  53  of  FIG. 7   c.    
     If unauthorized persons wish to determine which coding is present in a given lock cylinder, they try to find out about the position of the edges  43 ,  44  of the cutout  40 , which, as has been noted, are provided with bevels  48 . 1 ,  48 . 2  in the tumbler  41 ′. To make decoding more difficult for unauthorized persons, the coding can be “camouflaged” by providing additional beveled edges at  48 . 3  to  48 . 5 . Between the two edges  43 ,  44  of the cutout  40 , there is a connection between the two edges  43 ,  44  of the cutout  40 , and the edge of this connection can also be provided with a suitable bevel  48 . 3 . Finally, in  FIG. 5   b , the opening  39  has the edges  49 . 2  and  49 . 3  at the transition to the cutout  40 . These edges  49 . 2  and  49 . 3  can also be provided with bevels  48 . 4  and  48 . 5 . 
       FIG. 3  shows only an example of the position of a code point  28 . 3  of the code web  21 . In the longitudinal direction of the key bit  10 . 3 , there is a large number of additional scanning points, which are labeled  29 . 1  to  29 . 10  in  FIG. 8 . Naturally, to allow variation of the coding, the two web flanks are offset compared to  FIG. 3  in successive sections of the respective code webs  21  to  24 . The first code web  21 , which is highlighted by coarse point shading in  FIG. 8 , is formed in this way in the key bit  10 . 3  shown there. The possible range of variation of the web flanks is illustrated in  FIG. 2  by dot-dash lines  25 . 1  to  25 . 5  and  26 . 1  to  26 . 5 — 
     In  FIG. 2 , five different code points  28 . 1  to  28 . 5  are provided, in which the position of the corresponding pair of web flanks  25 . 1 ,  26 . 1  to  25 . 5 ,  26 . 5  can vary. In this regard, the associated code web has an essentially constant web width  20  over the entire axial length of the key bit  10 . 2 . Only in the case of large, immediately adjacent, increments will the code web be designed in some places with different web widths.  FIG. 2  already shows a possible extreme position of a pair of scanning points  28 . 1 , where both of the associated web flanks  25 . 1 ,  26 . 1  are in planes that extend past the edge  57 . 1  of the rectangular profile  17 . 
     Similar extreme pairs of scanning points are also found in  FIG. 8  in the code web  24  of the key bit  10 . 3  shown there. Ten axially spaced scanning points  29 . 1  to  29 . 10  are provided. In  FIG. 8 , the edge  57 . 1  of the rectangular profile  17 ′ is replaced by a dot-dash line where the code web  21  crosses the edge  57 . 1 . It is apparent that this occurs, e.g., at the scanning points  29 . 3  and  29 . 9 . 
     As  FIGS. 3 and 4  show, the facing sides  34  of the angular recesses located on the sides of the code web  21  are perpendicular to the direction of movement  47 . 1  of the tumbler  41  located there. Moreover, the two sides of the code web  21  are arranged parallel to each other. Naturally, it would also be conceivable that these angle sides  34  could be at a certain slant to the direction of movement  47 . 1 . The web  21  would then have a trapezoidal cross section. In addition, the angle sides  34  are straight lines in  FIGS. 3 and 4 . An alternative to this would be for the sides  34  to be curved  70  (see  FIG. 1 ), with either a convex  71  or a concave  72  curvature. 
     The other side  35  of the angle of  FIG. 3  is essentially parallel to the direction of movement  47 . 1  of the associated tumbler  41 . The two sides  34 ,  35  of the angle enclose a vertex angle, which in the present case, as has already been mentioned, is a right angle. As  FIG. 2  shows, these other angle sides  35  lie in a common base plane  36 . This base plane  36  intersects the corner region  30 . 1  obliquely. Alternatively, it would also be possible, at least in certain places, to arrange the two sides  35 , which are located on opposite sides of a code web and which extend in the direction of movement of the tumbler  41 , in such a way that they are vertically offset from each other. 
     In the present case, the variation of the position of the pairs of code points  28 . 1  to  28 . 5  of  FIG. 2  occurs in the aforesaid common base plane  36 . This base plane  36  determines the overall axial length of the corresponding key bit  10 . 1  to  10 . 3 . Alternatively, it would be possible for a base plane of this type to have parts at different heights, at least in certain axial sections of the code webs. 
     As noted earlier, in both embodiments  10 . 1  and  10 . 2 , the key bits have a rectangular profile  17 . Alternatively, a hexagonal or octagonal profile can be used as the cross section.  FIGS. 6 to 10  show a key bit  10 . 3  with a special edge profile  17 ′, which can be referred to as a “prismatic profile” due to the following special design, which is apparent from  FIG. 9 . 
     As shown in  FIG. 9 , the prismatic profile  17 ′ also has four active edges  57 . 1  to  57 . 4 , which are used to create four code webs  21  to  24  according to  FIG. 10 . The difference from the preceding rectangular profile of  FIGS. 1   b  to  4  is essentially that the second and fourth lateral surfaces  12 ′,  14 ′ form roof-like structures. This results in the formation of roof profile sections  60  between the edges  57 . 1  and  57 . 4 , on the one hand, and  57 . 2  and  57 . 3 , on the other hand. These roof profile sections  60  produce roof surfaces  58 . 1 ,  58 . 2  that are positioned at an angle to each other, one on each side of the associated vertex  59 . 1  and  59 . 2 . This results in a more or less “hexagonal profile”, which is irregular but exhibits folding symmetry, and whose two vertices  59 . 1  and  59 . 2  are not used for coding. The two roof profile sections  60  on the two opposing lateral surfaces  12 ′,  14 ′ are symmetrical to each other and have the advantage of increasing the ability to vary the arrangement of the pairs of code points  58 . 1  to  58 . 5 , as can be made clear on the basis of  FIGS. 2 and 9 . 
       FIG. 9  shows that the roof surface  58 . 1  forms a roof angle  61  of about 15° to the edge  57 . 4 . When this same angle  61  is drawn in with respect to the edge  57 . 1  in  FIG. 2  as the dotted auxiliary line  62  shown in  FIG. 2 , it can be seen that additional key cross-sectional area is obtained in front of the first pair of code points  28 . 1 , and this area can be used to achieve further variation of the coding. In terms of the coding to be carried out, the same situation exists at the other edge  57 . 1  shown in  FIG. 9 , where again additional area is provided by the roof surface  58 . 2  of the roof profile section  60 . Even though the width of the web cross section is increased slightly by the flat roof profile sections  60 , relatively large roof surfaces  58 . 1 ,  58 . 2  are obtained, which allow additional variation of the positions of the pairs of code points. 
     As  FIGS. 6 to 10  show, in the third embodiment  10 . 3  of the key bit of the invention, all four edges  57 . 1  to  57 . 4  are provided with code webs  21  to  24 , and code webs that lie opposite each other, as is shown especially well in  FIG. 10 , have identical coding, namely,  21 ,  23 , on the one hand, and  22 ,  24 , on the other hand. This key bit  10 . 3  constitutes a so-called “either-way key”, which can be inserted in the keyway  53  of the cylinder core  52  in either of two positions 180° apart. In this device, as  FIGS. 6 to 7   a  show, there are two types of tumblers  41 ,  42  with respect to their orientations in the cylinder core  52 . The first type of tumbler  41  scans the pairs of code points along the code web  22 , for example, while the other type of tumbler  42  interacts with the code web  23 . In either of the “either-way” positions of the key, the two types of opposing code webs  24  to  21  will engage with the two types of tumblers  41  and  42 . 
     As is shown especially well in  FIGS. 6 and 7   b , the two tumblers  41 ,  42  are angularly offset from each other, with the offset angle corresponding to the angular offset of the associated code webs  22 ,  23 . In the present case, it is a 90° angle. As illustrated by arrows  47 . 1  and  47 . 2 , the directions of movement  47 . 1 ,  47 . 2  of the two types of tumblers  41 ,  42  are also arranged at an angle to each other, which in this case is 90°. Moreover, the two types of tumblers  41 ,  42  alternate with each other in the cylinder core  52 , which means that two adjacent tumblers  41 ,  42  will move longitudinally in different directions in the keyway  53 . 
     As illustrated in dot-dash line in  FIG. 4 , one of the edge regions  33  can be cut away, as illustrated at  37 . This saves space, because the associated cutout  40  in the tumbler  41  does not have to be as deep. This does not adversely affect the size of the crucial scanning points  15 ,  16  on both sides of the code web  21  of the key bit  10 . 2 . Instead of a cutaway  37  of this type, the edge could also be rounded  73  in the corner region. 
     LIST OF REFERENCE NUMBERS 
     
         
           10 . 1  first key bit with a code web ( FIG. 1   a ) 
           10 . 2  second key bit with four code webs ( FIGS. 1   b  to  4 ) 
           10 . 3  third key bit with prismatic profile ( FIGS. 6 to 10 ) 
           11  first lateral surface of  10 . 2  ( FIGS. 1   a  to  4 ) 
           12  second lateral surface of  10 . 2  ( FIGS. 1   a  to  4 ) 
           12 ′ second lateral surface of  10 . 3  ( FIG. 9 ) 
           13  third lateral surface of  10 . 2  ( FIGS. 1   a  to  4 ) 
           14  fourth lateral surface of  10 . 2  ( FIGS. 1   a  to  4 ) 
           14 ′ fourth lateral surface of  10 . 3  ( FIG. 9 ) 
           15  first scanning point on  11  ( FIGS. 3 ,  4 ) 
           16  second scanning point on  11  ( FIGS. 3 ,  4 ) 
           17  edge profile, rectangle ( FIGS. 1   a  to  4 ) 
           17 ′ edge profile, prismatic profile of  10 . 3  ( FIGS. 6 to 10 ) 
           18  width of  10 . 1  ( FIG. 1   a ) 
           19  height of  10 . 1  ( FIG. 1   a ) 
           20  web width ( FIG. 2 ) 
           21  first code web at  30 . 1  ( FIG. 1   b ) 
           22  second code web at  30 . 2  ( FIG. 1   b ) 
           23  third code web at  30 . 3  ( FIG. 6 ) 
           24  fourth code web at  30 . 4  ( FIG. 1   b ) 
           25 . 1  first web flank of  21  at  28 . 1  ( FIG. 2 ) 
           25 . 2  first web flank of  21  at  28 . 2  ( FIG. 2 ) 
           25 . 3  first web flank of  21  at  28 . 3  ( FIG. 2 ) 
           25 . 4  first web flank of  21  at  28 . 4  ( FIG. 2 ) 
           25 . 5  first web flank of  21  at  28 . 5  ( FIG. 2 ) 
           26 . 1  second web flank of  21  at  28 . 1  ( FIG. 2 ) 
           26 . 2  second web flank of  21  at  28 . 2  ( FIG. 2 ) 
           26 . 3  second web flank of  21  at  28 . 3  ( FIG. 2 ) 
           26 . 4  second web flank of  21  at  28 . 4  ( FIG. 2 ) 
           26 . 5  second web flank of  21  at  28 . 5  ( FIG. 2 ) 
           27  key axis of  10 . 3  ( FIGS. 6 ,  7   c ,  8 ) 
           28 . 1  first pair of code points, first code point ( FIG. 2 ) 
           28 . 2  second pair of code points, second code point ( FIG. 2 ) 
           28 . 3  third pair of code points, third code point ( FIG. 2 ) 
           28 . 4  fourth pair of code points, fourth code point ( FIG. 2 ) 
           28 . 5  fifth pair of code points, fifth code point ( FIG. 2 ) 
           29 . 1  first scanning point ( FIG. 8 ) 
           29 . 2  second scanning point ( FIG. 8 ) 
           29 . 3  third scanning point ( FIG. 8 ) 
           29 . 4  fourth scanning point ( FIG. 8 ) 
           29 . 5  fifth scanning point ( FIG. 8 ) 
           29 . 6  sixth scanning point ( FIG. 8 ) 
           29 . 7  seventh scanning point ( FIG. 8 ) 
           29 . 8  eighth scanning point ( FIG. 8 ) 
           29 . 9  ninth scanning point ( FIG. 8 ) 
           29 . 10  tenth scanning point ( FIG. 8 ) 
           30 . 1  first corner region of  10 . 2  ( FIGS. 1   b ,  2 ) 
           30 . 2  second corner region of  10 . 2  ( FIG. 1   b ) 
           30 . 3  third corner region of  10 . 2  ( FIG. 1   b ) 
           30 . 4  fourth corner region of  10 . 2  ( FIG. 1   b ) 
           31  first angular recess in  11  ( FIG. 3 ) 
           32  second angular recess in  12  ( FIG. 3 ) 
           33  cutaway edge region in  21  ( FIG. 4 ) 
           34  first side of the angle of  31 ,  32  ( FIG. 3 ) 
           35  second side of the angle of  31 ,  32  ( FIG. 3 ) 
           36  base plane of  35  ( FIG. 2 ) 
           37  cutting line for  33  ( FIG. 4 ) 
           38  projection of  41  ( FIG. 5   a ) 
           39  opening in  41  or  41 ′ ( FIG. 5   a ) 
           40  cutout in  41 ,  41 ′,  42  ( FIGS. 4 ,  5   a ,  5   b ;  7   a ,  7   b ) 
           41  tumbler ( FIGS. 4 ,  5  to  7   b ) 
           41 ′ tumbler ( FIG. 5   b ) 
           42  tumbler ( FIGS. 6 ,  7   b ) 
           43  first edge of the cutout  40  ( FIG. 4 ) 
           44  second edge of the cutout  40  ( FIG. 4 ) 
           45  first cooperating scanning point of  41  at  40  ( FIG. 4 ) 
           46  second cooperating scanning point of  41  at  40  ( FIG. 4 ) 
           47 . 1  direction of movement of  41  ( FIGS. 4 ,  6  to  7   c ) 
           47 . 2  direction of movement of  42  ( FIGS. 6 ,  7   b ) 
           48 . 1  beveled edge at  43  ( FIG. 5   b ) 
           48 . 2  beveled edge at  44  ( FIG. 5   b ) 
           48 . 3  beveled edge at  29 . 1  [sic— 49 . 1 ] ( FIG. 5   b ) 
           48 . 4  beveled edge at  29 . 3  [sic— 49 . 3 ] ( FIG. 5   b ) 
           48 . 5  beveled edge at  29 . 2  [sic— 49 . 2 ] ( FIG. 5   b ) 
           49 . 1  connection between  43 ,  44  ( FIG. 5   b ) 
           49 . 2  first edge of  39  at  40  ( FIG. 5   b ) 
           49 . 3  second edge of  39  at  40  ( FIG. 5   b ) 
           50  lock cylinder ( FIG. 7   c ) 
           51  stationary cylinder housing ( FIG. 7   c ) 
           52  cylinder core in  51  ( FIG. 7   c ) 
           53  keyway in  52  ( FIG. 7   c ) 
           54  spring for  41  ( FIG. 7   c ) 
           55 . 1  first blocking channel for  41  ( FIG. 7   c ) 
           55 . 2  second blocking channel for  41  ( FIG. 7   c ) 
           56 . 1  first blocking channel for  42  ( FIG. 7   c ) 
           56 . 2  second blocking channel for  42  ( FIG. 7   c ) 
           57 . 1  first edge of  17 ;  17 ′ ( FIGS. 8 to 10 ) 
           57 . 2  second edge of  17 ;  17 ′ ( FIGS. 8 to 10 ) 
           57 . 3  third edge of  17 ;  17 ′ ( FIGS. 8 to 10 ) 
           57 . 4  fourth edge of  17 ;  17 ′ ( FIGS. 8 to 10 ) 
           58 . 1  first roof surface of  60  ( FIG. 9 ) 
           58 . 2  second roof surface of  60  ( FIG. 9 ) 
           59 . 1  first vertex of  60  ( FIG. 9 ) 
           59 . 2  second vertex of  60  ( FIG. 9 ) 
           60  roof profile section at  17 ′ ( FIG. 9 ) 
           61  roof angle of  60  ( FIGS. 9 ,  2 ) 
           62  auxiliary line for  61  ( FIG. 2 ) 
           63  angle between  47 . 1 ,  47 . 2  ( FIG. 7   b ) 
           70  curved line 
           71  convex shape 
           72  concave shape 
           73  rounded edge