Abstract:
A safety razor with a plurality of blades comprising a head provided with a plurality of vertically adjacent blades, which do not wholly overlap one another, and blade support parts supporting the respective blades apart from one another in order to retain the respective blades at spaces, and wherein non-overlapping portions, which do not overlap one another, are formed on supported portions of the respective blades and the blade support parts are held to the non-overlapping portions of the blades to support the blades. A support structure can be divided into two members to be manufactured and mechanically assembled, metal molds are not so much complicated, and mechanical assembly of blades is made possible to prevent degradation in yield.

Description:
TECHNICAL FIELD  
         [0001]    The present invention relates to a safety razor having a plurality of blades, and more particular, to a structure, in which respective blades are supported at spaces.  
         BACKGROUND ART  
         [0002]    A safety razor having a plurality of blades suffers from accumulation of moustache refuse, cream, or the like between blades in use, and so a safety razor intended for efficient removal of these has been proposed. JP-A-2000-308771 discloses a support structure, in which a plurality of blades are supported at spaces. This support structure comprises a plurality of blades and a frame supporting the plurality of blades, a plurality of vertical ribs are arranged between opened rear portions of the frame, and the ribs comprise slots, which are different in level and in which rear edges of the blades are mounted.  
           [0003]    A conventional support structure is configured in the above-mentioned manner such that rear edges of the blades are mounted in the slots provided on the ribs. In this manner, with the support structure, in which blades are fixed by means of slots, it is difficult to separately manufacture several support structure parts to mechanically assemble them, so that the whole support structure together with blades is molded by fixing the blades in predetermined positions and injection molding plastics. Cartridge replaceable blades are manufactured by such injection molding.  
           [0004]    However, there is a disadvantage that metal molds used in injection molding to manufacture a whole cartridge replaceable blade in a body are very complicated to lead to an increase in cost. Also, it is not easy to fix a plurality of blades at spaces at the time of injection molding, which incurs a fear of bad yield.  
           [0005]    Hereupon, it is an object of the invention to provide a constitution, in which a support structure is divided into two members to be manufactured and mechanically assembled and metal molds are not so much complicated.  
           [0006]    Further, it is an object of the invention to enable mechanical assembly of blades and prevent degradation in yield.  
           [0007]    Further, with a safety razor having a plurality of blades, respective blade bodies are partially fixed midway in order to efficiently eject moustache refuse, which has been clogged between the blades, rearward, whereby spaces between blade bodies are retained. Therefore, there is a fear that blade bodies bend at unfixed portions thereof. Also, when a safety razor having a plurality of blades is assembled, the blades are stacked on one another, but the stacked blades can be shifted relative to one another due to vibrations prior to fixation of the blades, which leads to a bad yield. Hereupon, it is an object of the invention to provide a safety razor, assembly of which can be readily and surely performed and in which blades after assembly are surely fixed.  
         DISCLOSURE OF THE INVENTION  
         [0008]    The invention according to claim  1  has a feature in that a head is provided with a plurality of vertically adjacent blades, which do not wholly overlap one another, and blade support parts supporting the respective blades apart from one another in order to retain the respective blades at spaces, and that non-overlapping portions, which do not overlap one another, are formed on supported portions of the respective blades and the blade support parts are held to the non-overlapping portions of the blades to support the blades.  
           [0009]    The invention according to claim  2  adds to the constitution of claim  1  a constitution, in which when the blades are provided with holes or notches, the non-overlapping portions are present on at least any one of blade edges, which include edges of the holes or notches.  
           [0010]    According to claim  3 , the non-overlapping portions are present on front and rear edge portions of the blades, and according to claim  4 , the respective blades are formed to be rectangular in shape and provided with holes, and the non-overlapping portions are present on inner periphery front edges and inner periphery rear edges of the holes.  
           [0011]    According to claim  5 , the respective blades are formed to have the same external shape, and vertically adjacent blades are shifted relative to each other to produce the non-overlapping portions, and the invention according to claim  6  is constituted such that the respective blades are provided at both ends thereof with notches, a shape of which is obtained by dividing the hole into two halves, and the non-overlapping portions are present on inner periphery front edges and inner periphery rear edges of the notches.  
           [0012]    According to claim  7 , a plurality of blades are supported between a blade base and a roof plate and that those blade support parts, which are provided integrally on the blade base to project therefrom, support the non-overlapping portions of those blades, which are disposed above a lower blade, from under and those blade support parts, which are provided integrally on the roof plate to project therefrom, support the non-overlapping portions of those blades, which are disposed below an upper blade, from above, whereby the respective blades are supported in different levels.  
           [0013]    According to claim  8 , the non-overlapping portions of those blades, which are supported by the blade support parts of a blade base, are composed of both sides of rear edges of the blades, inner periphery front edges of the holes, and inner periphery front edges of notches, and the non-overlapping portions of those blades, which are supported by the blade support parts of a roof plate, are composed of both sides of front edges of the blades, inner periphery rear edges of the holes, and inner periphery rear edges of notches.  
           [0014]    According to claim  9 , projections themselves projecting from a bottom surface of a roof plate to be inserted through holes of the respective blades and holes of a blade base in order to interpose the blades between the blade base and the roof plate support those blades, which are disposed below an upper blade. Also, according to claim  10 , steps are provided midway the projections and the steps support the non-overlapping portions of those blades, which are disposed below the upper blade, from above.  
           [0015]    The invention according to claim  11  has a feature in that a head is provided with three or more vertically adjacent blades, which do not wholly overlap one another, and blade support parts supporting the respective blades apart from one another in order to retain the respective blades at spaces, and that non-overlapping portions, which do not overlap one another, are formed on supported portions of the respective blades and the blade support parts are held to the non-overlapping portions of the blades to support the blades.  
           [0016]    According to claim  12 , projections themselves projecting from a bottom surface of a roof plate to be inserted through holes of the respective blades and holes of a blade base in order to interpose the blades between the blade base and the roof plate support those blades, which are disposed below an upper blade. According to claim  13 , steps are provided midway the projections and the steps support those blades, which are disposed below the upper blade, from above, and according to claim  14 , the number of steps supporting those blades, which are disposed below the upper blade, corresponds to the number of blades minus 1.  
           [0017]    According to claim  15 , a plurality of blade support parts supporting the blades are changed relatively in level whereby all or a part of the blades are supported to be non-parallel. According to claim  16 , an extension line extending ahead of a blade edge from a lower blade and an extension line extending ahead of a blade edge from an upper blade intersect each other ahead of the blade edges. In contrast with this, according to claim  17 , an extension line extending ahead of a blade edge from a lower blade and an extension line extending ahead of a blade edge from an upper blade are increased in spacing as they go ahead of the blade edges. According to claim  18 , moustache refuse, cream, or the like is discharged through gaps between the respective blades from a rear end opening of the head.  
           [0018]    The invention according to claim  19  adds limitatively to the constitution of claims  11  to  18  a constitution, in which three or more blades are provided, a spacer member is present between a lower blade and blades above the lower blade, the spacer member is provided with an insertion hole, a tip end of a projection extending through the upper blade and the respective middle blades from a bottom surface of a roof plate is inserted through the insertion hole, a rear end of the spacer member is provided with an upward directed projection, and the projection bears on the upper blade with a non-overlapping portion of the blade therebetween.  
           [0019]    The invention according to claim  20  is directed to a safety razor comprising a plurality of blades mounted at predetermined spaces on a head and an insert spacer inserted between the blades from a rear end opening of the head to be fixed. The invention according to claim  21  is directed to a safety razor comprising three or more blades, and wherein a plurality of insert pieces project from a base end of the insert spacer to be different in level, and the respective insert pieces are inserted between the respective blades. The invention according to claim  22  adds limitatively to the constitution of claim  21  a constitution, in which at least ones of the vertically adjacent insert pieces are laterally provided in plural, and the vertically adjacent insert pieces are alternately arranged laterally.  
           [0020]    With the invention constituted in the above-mentioned manner, the blade support parts are held to the non-overlapping portions of the blades to thereby support the respective blade bodies apart from one another. That is, instead of fixing blades integrally in slots by means of injection molding, the blade support parts are held to the non-overlapping portions of the blades to support the blades, so that mechanical assembly of support structure parts is made possible. Accordingly, metal molds are not so much complicated and it is not necessary to fix blade bodies to perform injection molding, so that manufacture is simple and inexpensive as compared with conventional products. Also, degradation in yield is eliminated.  
           [0021]    According to claim  9 , projections themselves projecting from a bottom surface of a roof plate to be inserted through holes of the respective blades and holes of a blade base in order to interpose the blades between the blade base and the roof plate support those blades, which are disposed below an upper blade. Accordingly, even when blade body supports and blade base inserts are not formed separately, the projections serve as both parts to produce an effect that the constitution is made simple and cost is reduced.  
           [0022]    According to claim  14 , the number of steps provided on the projections to support those blades, which are disposed below the upper blade, corresponds to the number of blades minus  1 . Accordingly, all blades disposed below the upper blade are supported by the respective steps, so that it is possible to stably support the blades.  
           [0023]    According to claim  19 , three or more blades are provided, a spacer member is present between a lower blade and blades above the lower blade, the spacer member is provided with an insertion hole, a tip end of a projection extending through the upper blade and the respective middle blades from a bottom surface of a roof plate is inserted through the insertion hole, a rear end of the spacer member is provided with an upward directed projection, and the projection bears on the upper blade with a non-overlapping portion of the blade therebetween. As described in, for example, claim  5 , when blade bodies are shifted and a safety razor is assembled, the roof plate is placed in an inverted position, a plurality of blades are shifted and stacked in a stepwise manner, and the blade base is held thereto to be fixed. And when the blade base is held to an associated part, there is a fear that middle blades placed in a stepwise manner are shifted due to vibrations of an associated machine to fall on blades disposed below, but the spacer member is stacked to push the blades disposed below, thus enabling preventing the blades from being shifted. Also, while the lower blade meets with largest resistance from moustache, the spacer member holds the lower blade down to enable surely fixing the lower blade.  
           [0024]    As described above, in recent years, with a safety razor having a plurality of blades, respective blade bodies are partially fixed midway in order to efficiently eject moustache refuse, which has been clogged between the blades, rearward, and spaces between blade bodies are retained. Therefore, there is a fear that blade bodies bend at unfixed portions thereof. According to claim  20 , a safety razor comprises a plurality of blades mounted at predetermined spaces on a head and an insert spacer inserted between the blades from a rear end opening of the head to be fixed. Accordingly, the respective blades can be surely and simply fixed by manufacturing an insert spacer and mounting the same on a safety razor.  
           [0025]    According to claim  22 , at least ones of the vertically adjacent insert pieces are laterally provided in plural, and the insert pieces vertically adjacent to the ones are alternately arranged laterally. Accordingly, the insert pieces can be easily inserted into the head as compared with the case where vertically adjacent insert pieces fully overlap each other. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0026]    [0026]FIG. 1 is a cross sectional view taken along the line B-B in FIG. 3;  
         [0027]    [0027]FIG. 2 is a cross sectional view taken along the line A-A in FIG. 3;  
         [0028]    [0028]FIG. 3 is a top plan view showing a head;  
         [0029]    [0029]FIG. 4 is a bottom view showing a roof plate;  
         [0030]    [0030]FIG. 5 is a front view showing the roof plate;  
         [0031]    [0031]FIG. 6 is a side view showing the roof plate;  
         [0032]    [0032]FIG. 7 is a cross sectional view taken along the line C-C in FIG. 4;  
         [0033]    [0033]FIG. 8 is a top plan view showing a blade base;  
         [0034]    [0034]FIG. 9 is a cross sectional view taken along the line D-D in FIG. 8;  
         [0035]    [0035]FIG. 10 is a top plan view showing an upper blade and a middle blade;  
         [0036]    [0036]FIG. 11 is a top plan view showing a lower blade;  
         [0037]    [0037]FIG. 12 is a view illustrating an assembly step of the head;  
         [0038]    [0038]FIG. 13 is a cross sectional view showing a state after the completion of the assembly step of the head;  
         [0039]    [0039]FIG. 14 is a cross sectional view showing the head;  
         [0040]    [0040]FIG. 15 is an exploded, cross sectional view showing a head;  
         [0041]    [0041]FIG. 16 shows a top plan view, a back side view, and a side view showing a spacer member;  
         [0042]    [0042]FIG. 17 is a cross sectional view showing the spacer member;  
         [0043]    [0043]FIG. 18 is a top plan view showing an upper blade;  
         [0044]    [0044]FIG. 19 is a top plan view showing a middle blade;  
         [0045]    [0045]FIG. 20 is a top plan view showing a lower blade;  
         [0046]    [0046]FIG. 21 is a bottom view showing the roof plate;  
         [0047]    [0047]FIG. 22 is a top plan view showing a state, in which the upper blade, the middle blade, and the spacer member are stacked on the roof plate made upside down;  
         [0048]    [0048]FIG. 23 is a partial, cross sectional view showing an assembled state of the head;  
         [0049]    [0049]FIG. 24 is a cross sectional view showing a head;  
         [0050]    [0050]FIG. 25 is a top plan view showing an insert spacer;  
         [0051]    [0051]FIG. 26 is a front view showing the insert spacer;  
         [0052]    [0052]FIG. 27 is a back side view showing the insert spacer;  
         [0053]    [0053]FIG. 28 is a side view showing the insert spacer;  
         [0054]    [0054]FIG. 29 is a cross sectional view showing the insert spacer;  
         [0055]    [0055]FIG. 30 is a top plan view showing a state, in which a roof plate and an upper blade are removed from the head; and  
         [0056]    [0056]FIG. 31 is a back side view showing the head. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0057]    Embodiments of the invention will be described below with reference to the drawings. The drawings show a cartridge replaceable blade having three blades, the cartridge replaceable blade corresponding to a head  53  of a safety razor, and a support structure for blades comprising a roof plate  1  and a blade base  2 . The roof plate  1  comprises a blade pressure foot  4  between both side portions  3 ,  3 , and a guard body  5  extending between both front ends of the both side portions  3 ,  3  and interposing an opening  6  between it and the blade pressure foot  4 . Edges of the blades are exposed from the opening  6 . Also, a shaving aid  49  is fixed in a recess  50  provided on an upper surface of the blade pressure foot  4 . Since two ridges are provided on a bottom of the recess  50 , the shaving aid  49  is firmly fixed. Of course, the invention is not limited to cartridge replaceable blades but may be applied to safety razors, in which a blade base and a handle are integrally formed.  
         [0058]    As shown in FIGS. 1 and 2, blade support parts are formed stepwise. FIG. 4 is a bottom view showing the roof plate  1 , and as shown in the figure, four first blade support parts  7  are arranged on a bottom surface of the blade pressure foot  4 . The blade pressure foot  4  together with blade base inserts  13  projects as integral projections from a bottom surface of the roof plate. Also, two second blade support parts  8  are provided on bottom surfaces of the both side portions  3 ,  3  to be positioned forwardly of the first blade support parts  7 . As described above, the blade support parts are formed to be stepwise, and steps comprise two steps composed of a second step and a first step. For the first blade support parts  7 , the second step  9  is positioned forward and the first step  10  is positioned rearward. For the second blade support parts  8 , the second step  11  is positioned forward and the first step  12  is positioned rearward. As described later, the second steps  9  and the first steps  10  in the respective blade support parts  7 ,  8  abut against non-overlapping portions of the respective blades to support the blades.  
         [0059]    As described above, the reference numeral  13  denotes blade base inserts projecting from the second steps  9  of the first blade support parts to extend through holes in the blades and the blade base to fix the blades between the blade base and the roof plate  1 . The blade base inserts are not limited to a circular shape in cross section but may be rectangular in cross section. In the case where the blade base inserts are rectangular in cross section, they preferably have the same width as that of the first blade support parts  7 . Also, the reference numeral  14  denotes projections provided on a bottom surface of the guard body  5  to extend through holes in the blade base to join the blade base  2  and the roof plate  1  together. Also, since a shaving aid  33  is present on a surface of the guard body  5 , it is possible to perform shaving smoothly.  
         [0060]    [0060]FIG. 8 is a top plan view showing the blade base  2 , four third blade support parts  16  being arranged in alignment around the middle of an upper surface as shown in the figure. Also, four fourth blade support parts  17  are arranged in alignment along a rear end of the upper surface. Like the first and second blade support parts  7 ,  8  described above, the third and fourth blade support parts  16 ,  17  are formed to be stepwise, and steps comprise two steps composed of a second step and a first step. For the third blade support parts  16 , the second step  18  is positioned rearward and the first step  19  is positioned forward. For the fourth blade support parts  17 , the second step  20  is positioned rearward and the first step  21  is positioned forward.  
         [0061]    The reference numeral  22  denotes holes, through which the blade base inserts  13  are inserted. Also, the reference numeral  23  denotes holes provided on a guard base  24  of the blade base  2 , and the projections  14 , described above, on the roof plate extend through the holes. An elastomer portion  31  is provided upright along a tip end of the guard base  24 . The reference numeral  52  denotes an extrusion portion of the elastomer portion  31 , the extrusion portion engaging with a groove in the blade base  2  to thereby fix the elastomer portion  31  to the blade base  2  firmly. The guard body  5  of the roof plate is fitted into a groove  32  formed by the guard base  24  and the elastomer portion  31  whereby a surface of the guard is formed such that a surface of the elastomer portion  31  and a surface of the shaving aid  33  extend adjacent to and in parallel to each other.  
         [0062]    Blades used for the cartridge replaceable blade include two kinds, and a blade shown in FIG. 10 is used as an upper blade  25  and a middle blade  26 . The blade shown in FIG. 10 comprises five aligned holes  28  and notches  30 ,  30  at both ends thereof. A blade shown in FIG. 11 is used as a lower blade  27 . The blade shown in FIG. 11 comprises two aligned holes  29  and notches  43 ,  43  at both ends thereof. However, the blades in the invention are not limited to such combination but may be naturally of any combination. Accordingly, all the blades may be ones shown in FIG.  10 , or ones shown in FIG. 11.  
         [0063]    [0063]FIG. 12 is a view showing an assembling method in the invention. As shown in the figure, the roof plate  1  is shown as being inverted, and the upper blade  25  is first placed on the bottom surface  15  (an upper surface in FIG. 12) of the roof plate  1 . At this time, the blade base inserts  13  and the first blade support parts  7  are inserted through the holes  28 ,  28  provided adjacent to the central one, among the five holes  28  in the upper blade.  
         [0064]    Subsequently, the middle blade  26  is placed to be shifted a little forwardly of the upper blade  25 . Such shifting of the middle blade  26  prevents inner periphery rear edges  34  of the holes in the upper blade from wholly overlapping with inner periphery rear edges  35  of the holes in the middle blade  26 , thus generating non-overlapping portions. Owing to the presence of the non-overlapping portions, only the blade base inserts  13  and the second steps  9  of the first blade support parts are inserted through the holes  28 , and the first steps  10  are blocked by the inner periphery rear edges  35  of the middle blade to act to support the middle blade. That is, the inner periphery rear edges  35  of the middle blade are supported by the first steps  10  of the first blade support parts. Such supporting is effected between the inner periphery rear edges  36 ,  36  of the notches  30 ,  30  at both ends and the first blade support parts  7 ,  7  provided on the bottom surfaces of the both side portions  3 ,  3  of the roof plate.  
         [0065]    Shifting of the middle blade  26  further prevents a front edge  37  of the upper blade from wholly overlapping with a front edge  38  of the middle blade, thus generating non-overlapping portions. Owing to the presence of the non-overlapping portions, both ends of the front edge  38  of the middle blade are supported on the first steps  12  of the second blade support parts.  
         [0066]    After the middle blade  26  is placed in the manner described above, the lower blade  27  is placed in a state to be shifted a little forwardly of the middle blade  26 . Shifting of the lower blade  27  prevents the inner periphery rear edges  35  of the holes of the middle blade from wholly overlapping with inner periphery rear edges  42  of the holes of the lower blade, thus generating non-overlapping portions. Owing to the presence of the non-overlapping portions, only the blade base inserts  13  are inserted through the holes  29 , and the second steps  9  are blocked by the inner periphery rear edges  42  of the lower blade to act to support the lower blade  27 . That is, the inner periphery rear edges  42  of the lower blade are supported by the second steps  9  of the first blade support parts. Such supporting is also effected between the inner periphery rear edges  36 ,  36  of the notches  30 ,  30  at both ends and the first blade support parts  7 ,  7  provided on the bottom surfaces of the both side portions  3 ,  3  of the roof plate.  
         [0067]    Shifting of the lower blade  27  further prevents the front edge  38  of the middle blade  26  from overlapping with a front edge  39  of the lower blade  27 , thus generating non-overlapping portions. Owing to the presence of the non-overlapping portions, both ends of the front edge  39  of the lower blade are supported on the second steps  11  of the second blade support parts  8 .  
         [0068]    As described above, after the upper blade  25 , the middle blade  26 , and the lower blade  27  are set on the roof plate  1  as inverted, the blade base  2  is joined to the roof plate  1 . The roof plate  1  and the blade base  2  are joined together by also inverting the blade base  2 , inserting the blade base inserts  13  through the holes  22  of the blade base, inserting the projections  14  through the holes  23  of the blade base, and squashing tip ends of the blade base inserts  13  and the projections  14 , which project above the bottom surface of the blade base.  
         [0069]    When the roof plate  1  and the blade base  2  are joined together, the second steps  20  of the fourth blade support parts provided on an upper surface (an underside in FIG. 12) of the blade base come into pressure contact with a rear edge portion  40  and the inner periphery rear edges  34  of the upper blade, at which the upper blade  25  and the middle blade  26  do not overlap with each other, and the first steps  21  come into pressure contact with a rear edge portion  41  and the inner periphery rear edges  35  of the middle blade, at which the middle blade  26  and the lower blade  27  do not overlap with each other. Also, an upper surface  46  of the blade base comes into pressure contact with the inner periphery rear edges  42  of the lower blade.  
         [0070]    Simultaneously therewith, the second steps  18  of the third blade support parts pass through the holes  29  of the lower blade and the holes  28  of the middle blade to come into pressure contact with inner periphery front edges  45  of the holes of the upper blade, and the first steps  19  pass through the holes  29  of the lower blade to come into pressure contact with inner periphery front edges  47  of the holes of the lower blade. Also, the upper surface  46  of the blade base comes into pressure contact with inner periphery front edges  48  of the holes of the lower blade. Further, the third blade support parts  16  come into pressure contact with inner periphery front edges  44  of the notches of the respective blades.  
         [0071]    By assembling the cartridge replaceable blade in the above manner, the inner periphery rear edges  34 ,  35 ,  42  of the holes of the respective blades are interposed from above and under in a pressure-contact state, and both ends of the front edge  37 ,  38 ,  39  of the respective blades are put into a pressure-contact state from above and under. Also, the inner periphery front edges  45 ,  47 ,  48  of the holes of the respective blades are put into a pressure-contact state from under, and the inner periphery front edges  45  of the holes of the respective blades are also pressure-contacted by the blade pressure foot  4 . In this manner, the respective blades can be surely fixed by pressure contact on the respective blades. In addition, of course, the invention is not limited to the three-blade arrangement but may be applied to arrangements having two blades, four blades or more. When the cartridge replaceable blade comprises four or more blades, it suffices to increase the number of steps on blade support parts.  
         [0072]    As shown in FIG. 1 or  13 , by inclining the second steps and the first steps of the respective stepwise blade support parts  7 ,  8 ,  16 ,  17  a little, the respective blades are made non-parallel to one another and extension lines extending beyond blade edges from the respective blades intersect one another ahead of the blade edges. Also, when the second steps and the first steps are reversely inclined, setting can be made so that extension lines of the respective blades diverge ahead of the blade edges. It suffices that an inclination of the middle blade  26  relative to the lower blade  27  and an inclination of the upper blade  25  relative to the middle blade  26 , respectively, be not much more than 5 degrees. Accordingly, such inclination may be 1, 2, 3, or 4 degrees. Preferably, the inclination is around 3 degrees. Based on this, an inclination of the upper blade relative to the lower blade  27  will become around 10 degrees. However, of course, the invention is not limited to such numerical value.  
         [0073]    FIGS.  14  to  23  are views showing an embodiment of the invention according to claim  19 . The embodiment provides a safety razor having three blades, and since a constitution, in which an upper blade  54 , a middle blade  55 , and a lower blade are shifted from and stacked on one another, is substantially the same as that in the embodiment described above, an explanation thereof is omitted. As shown in FIG. 21, the embodiment is different from the embodiment described above in that blade support parts  57 ,  57  are rounded as compared therewith.  
         [0074]    As shown in FIG. 16, a spacer member  58  is in the form of a small piece to be integrally made of plastics, the spacer member being formed centrally thereof with an insertion hole  59  and provided at a rear end thereof with an upward directed projection  60 . The insertion hole  59  may be a through-hole or concave in shape. A projection  61  being inserted into the insertion hole  59  is provided on a bottom surface of a roof plate  62 . As shown in FIG. 21, a pedestal  63  is provided on a root of the projection  61 . The reason for the provision of the pedestal  63  is that by interposing the pedestal  63  between the upper blade  54  and the middle blade  55 , a gap is retained between the upper blade  54  and the middle blade  55  in the same manner as steps on the blade support parts  57 ,  57 .  
         [0075]    Auxiliary projections  64 ,  64  are integrally provided outside the blade support parts  57 ,  57 , and first steps  65  and second steps  66  are provided stepwise. The auxiliary projections  64 ,  64  act to have the second steps brought into pressure contact with the lower blade  56  to surely fix the lower blade.  
         [0076]    Subsequently, a method of assembling the spacer member  58  and other members together will be described. FIG. 22 shows a state, in which the roof plate  1  is upside down and the upper blade  54  and the middle blade  55  are stacked on each other with a spacing therebetween. As shown in FIG. 14, a projection  60  of the spacer member bears on the upper blade  54  with non-overlapping portions of the middle blade  55  and the upper blade  54  therebetween, and the projection  61  is inserted into the insertion hole  59 . In this state, the middle blade  55  is pushed by the spacer member  58  and there is no fear of slippage. Thereafter, the lower blade  56  is further stacked, and respective blade base inserts  67 ,  67  on both sides and projections  68 ,  68  at a front end are inserted and fitted into holes of the blade base, thus achieving assembling as shown in FIG. 14.  
         [0077]    [0077]FIG. 18 shows the upper blade  54  comprising a central hole  69 , through which the projection  61  is inserted, holes  70 ,  70 , which are disposed on both sides thereof and through which the blade support parts  57 ,  57  are inserted, and holes  71 ,  71 , which are disposed outside and through which the auxiliary projections  64 ,  64  are inserted. FIG. 19 shows the middle blade  55  comprising a central hole  72 , through which the projection  61  is inserted, holes  73 ,  73 , which are disposed on both sides thereof and through which the blade support parts  57 ,  57  are inserted, and holes  74 ,  74 , which are disposed outside and through which the auxiliary projections  64 ,  64  are inserted. FIG. 20 shows the lower blade  56  comprising holes  75 ,  75 , which are disposed to a center and through which the blade support parts  57 ,  57  are inserted, and holes  76 ,  76 , which are disposed outside and through which tip ends of the auxiliary projections  64 ,  64  are inserted. A state, in which respective blades are supported by actions of the auxiliary projections  64 ,  64  and the respective holes, is easly understandable from FIG. 23. An action of the projection  61  shown centrally in FIG. 23 is described below. As shown in FIG. 23, the projection  61  comprises a central step, the step pushing the middle blade  55  downward, the thus pushed middle blade  55  pushing the spacer member  58  downward, and further the pushed spacer member  58  biasing the lower blade  56  to prevent the lower blade from coming up. In addition, of course, the spacer member  58  is not limited to one in number but a plurality of spacer members may be mounted.  
         [0078]    FIGS.  24  to  31  are views showing an embodiment of the invention according to claims  20  to  22 . A head  53  according to the invention comprise rear end openings  77  as shown in FIG. 31. The rear end openings  77  may be partially covered by ribs  78  as shown in FIG. 31, or the rear end openings  77  may extend over an entire width of the head  53  with no ribs  78 . While the ribs  78  are formed integral with a blade base  79 , they are not limited to such structure but may be formed integral with, for example, a roof plate  80 .  
         [0079]    FIGS.  25  to  29  show a structure of an insert spacer  81  used in a safety razor having three blades. The insert spacer  81  is integrally formed of plastics to comprise two upper insert pieces  83 ,  83  and a single lower insert piece  84 , these insert pieces being different in level to extend substantially horizontally from a base end  82 , and a spacing corresponding substantially to a thickness of a blade is present between the upper insert pieces and the lower insert piece. The lower insert piece  84  is present between the upper insert pieces  83 ,  83 , and the respective lower and upper insert pieces are aligned laterally alternately. Latch projections  85 ,  85 , respectively, are provided on both sides of the insert spacer  81 . When mounted on the head  53 , the latch projections  85 ,  85  latch on the ribs  78  to prevent the insert spacer  81  from coming out of the head  53 .  
         [0080]    As apparent from FIGS. 28 and 29, the upper insert pieces  83  and the lower insert piece  84  are formed to be gradually reduced in thickness toward tip ends thereof. This is intended for corresponding to that configuration, in which respective extension lines of an upper blade  86 , a middle blade  87 , and a lower blade  88  along directions of blade edge intersect one another ahead as shown in FIG. 24.  
         [0081]    Subsequently, a method of mounting the insert spacer  81  on the head  53  is described. A width of the insert spacer  81  amounts to a length insertable between the both ribs  78 ,  78 . The insert spacer  81  is mounted on the head  53  by inserting the upper insert pieces  83 ,  83  of the insert spacer between the upper blade  86  and the middle blade  87  in a manner to insert the same into the rear end openings  77  disposed centrally, and inserting the lower insert piece  84  between the middle blade  87  and the lower blade  88 . When the insert spacer  81  is fully inserted, the latch projections  85 ,  85  latch on back surfaces of the ribs  78 , so that the insert spacer  81  will not come out after mounting.  
         [0082]    Of course, the insert spacer is not limited to such configuration but a plurality of insert spacers may be mounted on the head. Also, instead of relying on the above-mentioned latch structure, a way to fix the insert spacer may be such that, for example, a thickness of the upper and lower insert pieces  83 ,  84  is made larger than a spacing between adjacent blade bodies to achieve press fit.