Blade part assembling structure for electric shaver

The blade part assembling structure for electric shaver of this invention comprises fitting pins which are rotatably fitted to a blade mounting base, a movable blade mounted on the base in the first rotating positions of the fitting pins, and a stationary blade mounted on the base in the second rotating positions so that, in the case of dismounting the stationary blade, the movable blade will be locked with the fitting pins in the rotated positions of the fitting pins and any occurence of troubles during disassembling and re-assembling of the blade part by the user can be avoided.

TECHNICAL FIELD 
This invention relates to blade part assembling structures for electric 
shavers and, more particularly, to a blade part assembling structure for 
electric shavers wherein only a stationary blade performing a cutting 
action in cooperation with a movable blade can be dismounted from a blade 
block detachably mounted to a housing. 
BACKGROUND ART 
Referring concretely to a blade part assembling structure for electric 
shaver of the kind referred to which has been general, bosses are provided 
to project on a base which forming a part of the housing of the electric 
shaver, a push-up spring and movable and stationary blades are arranged to 
be overlapped onto each other so as to be sequentially inserted to these 
bosses, fitting pins having a disk-shaped flange part are urged into the 
bosses so as to hold the stationary blade in the uppermost position with 
the lower surface of the disk-shaped flange part of the fitting pin to 
thereby mount the blade block to a blade holder. However, in the case of, 
for example, sweeping cut hairs entered between the movable blade and the 
stationary blade in such conventional concrete example, the fitting pins 
urged into the bosses are pulled out and the stationary blade is 
dismounted to be cleaned but, in this case, the movable blade and push-up 
spring will be also dismounted from the base, simultaneously with the 
dismounting of the stationary blade. This will bring about various 
disadvantages when the electric shaver is actually used. That is, there 
have been problems that, in the case of reassembling the blade block after 
the sweeping is completed, the push-up spring and movable blade are 
mounted on the base, then the stationary blade is arranged to be 
overlapped on them and the fitting pins is pressed in and thus the 
re-assembling is very troublesome and inconvenient, and that, if the blade 
block is disassembled by an unskilled person, chances of trouble 
occurrence in the blade block and of loosing any one of these parts will 
increase. 
Further, the stationary blade 3 and movable blade 2 have been rigid blades 
of a thick material so that, though the sliding surfaces between the 
stationary blade 3 and movable blade 2 are finished by grinding or the 
like, a warp of about 0.01 mm will be produced and, when these blades are 
assembled, a clearance of about 0.02 mm will take place, whereby there has 
been caused such problem that, in case such very fine hair of about 0.005 
mm as downy hair is to be cut, such hair will be held in the clearance 
between the stationary blade 3 and the movable blade 2 and cannot be cut 
at all. 
DISCLOSURE OF THE INVENTION 
A primary object of the present invention is, therefore, to provide a blade 
part assembling structure for electric shaver wherein only a stationary 
blade can be dismounted and overhauled undependently of a movable blade 
and push-up spring and a blade block can be simply and reliably 
disassembled and assembled. 
Another object of the present invention is to provide a blade part 
assembling structure for electric shaver wherein one blade is made 
flexible and the comb-shaped teeth of this blade are brought into close 
contact with those of the other blade so that there may be no clearance 
between the stationary blade and movable blade and even such fine hair as 
downy hair can be smoothly cut. 
Another object of the present invention is to provide a blade part 
assembling structure for electric shaver which is suitable for shaving 
hair one by one in the case of, for example, shaving eyebrows. 
Another object of the present invention is to provide a blade part 
assembling structure for electric shaver having a push-up means which can 
bring the blades into close contact with each other. 
Other objects of the present invention will be made gradually apparent with 
the following disclosure with reference to embodiments. 
Now, according to the present invention, the above described conventional 
problems are solved in such that laterally extended fitting holes with its 
major diameter lying in the direction perpendicular to sliding direction 
of the movable blade are formed while the stationary blade is mounted by 
means of rotatable fitting pins having an upper end flange part of such 
elongated shape as a rectangular, elliptic or the like shape so that it is 
made possible to dismount only the stationary blade, and either or each of 
the stationary blade and movable blade is made resilient by rendering the 
thickness in their material or only of the blade edge portion to be small.

The disclosure shall be made in the followings with reference to drawings 
showing embodiments of the present invention. FIG. 1 is a perspective view 
showing an appearance of an example of the blade part assembling structure 
of electric shaver to which the present invention is to be applied. In 
this electric shaver, a blade holder 2 is extended out of one end of a 
housing 1 having a reciprocating driving mechanism therein and a blade 
block 3 is mounted to this blade holder 2. In FIGS. 2 to 6, 4 is a base 
which is formed of a synthetic resin molding and provided with mounting 
bosses 5 projecting in a line in the reciprocating direction of a driving 
rod derived from a reciprocal driving mechanism. 6 is a stationary blade 
formed of a material of a thickness of about 0.4 mm, in which laterally 
extended fitting holes 8 with its major diameter lying in the direction 
perpendicular to the sliding direction of a movable blade 7 and both edge 
comb-shaped teeth are formed, the comb-shaped teeth at one edge being a 
short blade 9 formed only in the tip portion in the driving direction of 
the movable blade 7 and the comb-shaped teeth at the other edge being a 
long blade 10 formed to be arcuate. The comb-shaped groove width of the 
stationary blade 6 is formed to be somewhat larger than the diameter of 
hair to be 0.12 to 0.15 mm, so that hair can be less caused to fall by the 
movable blade as compared with conventional movable blade of a groove 
width of about 0.3 to 0.5 mm and even such fine hair as downy hair can be 
cut to be shorter. The movable blade 7 is formed of a thin material of a 
thickness of about 0.2 mm and is provided with sliding holes 11 formed in 
slots extending in the reciprocating direction of the driving rod and 
slidably guided by the fitting bosses 5 and with both-edge comb-shaped 
teeth of which the comb-shaped teeth at one edge are of a short blade 12 
so as to correspond to the comb-shaped teeth of the stationary blade 6. 13 
is a driving rod engaging member provided on the movable blade 7 and 
integrally formed of a synthetic resin molding by means of an 
insert-molding to be thicker than the movable blade 7. When the driving 
rod engaging member is thus formed of the synthetic resin molding, the 
driving rod will not be scraped with edge part of the movable blade 7, so 
that no gap will be produced between the driving rod and the driving rod 
engaging member, the efficiency of the drive force transmission can be 
prevented from being reduced and noises due to any collision of the 
driving rod with the engaging member can be kept low even after the use 
for a long time. 14 is a push-up means formed of a flat plate made thin 
and provided with a thickness reduction to have a resiliency and with 
holes 15 for fitting the mounting bosses. 16 is a fitting pin of which 
flange part 17 at the upper end is formed in such elongated shape as a 
rectangular or elliptic shape and this pin is inserted in a central hole 
18 in the fitting boss 5. The inner diameter of the central hole 18 is 
made larger than the outer diameter of the fitting pin 16 urged therein 
within triangular ranges formed at least by the center of the central hole 
18 and the front and rear ends of guide surface of the fitting boss 5 with 
which the movable blade 7 is in sliding contact as shown in FIGS. 7 and 8 
whereas the inner diameter of the fitting boss 5 is made smaller than the 
outer diameter of the fitting pin 16 in the other ranges, whereby there 
are caused such effects that the guide surfaces of the fitting bosses 5 
with which the movable blade 7 is in sliding contact will not be deformed 
by the depression of the fitting pins 16 to fix the stationary blade 6 to 
the fitting bosses 5, the fitting pins 16 will not float up from the 
central hole 18, the reciprocation of the movable blade 7 will be smooth 
and the movable blade 7 will contact the stationary blade under a 
predetermined pressure. While not shown in the drawings of the embodiment, 
it can be easily conceived to form a steped part in the lower end portion 
of the fitting pins 16 as a means for preventing the fitting pins 16 from 
being pulled out. The blade block 3 is formed in such that the push-up 
means 14 is fitted to the fitting bosses 5 of the base 4, then the sliding 
holes 11 of the movable blade 7 are fitted to the fitting bosses 5, 
further the stationary blade 6 is mounted on the upper surface of the 
movable blade to fit the fitting bosses 5 in the fitting holes 8 of the 
stationary blade 6, the fitting pins 16 are urged into the central holes 
18 of these fitting bosses 5 and the lower surfaces of the flange parts 17 
of the fitting pins 16 are brought into contact with the upper surfaces of 
the peripheral edges of the fitting holes 8 located in the same direction 
as the sliding direction of the movable blade, so that, when the 
lengthwise direction of the flange parts 17 is made to intersect at right 
angles the sliding direction of the movable blade 7, these flange parts 17 
will freely pass through the fitting holes 8 and, with this posture of the 
flange parts 17, the lower surfaces of the flange parts 17 will engage the 
upper surfaces of both side edges of the sliding holes 11. At this time, 
the tip edges of the flat plate which is the push-up means 14 are on the 
back surfaces of the sliding parts of the movable blade and are in contact 
with vicinities of the comb-shaped teeth so that, being in contact with 
the back surfaces of the sliding parts, the movable blade 7 will be 
prevented from floating from the stationary blade 6 due to this action by 
means of the push-up means 14. It is needless to say that the sliding 
parts of the movable blade 7 include the ones in the form of points for 
reducing the sliding resistance. Further, as a means for preventing the 
stationary blade 6 from being deformed by the pressing force of the 
fitting pin 16, a projection 19 higher than the thickness of the 
stationary blade 6 is formed at the tip of the fitting boss 5 to 
correspond to the fitting hole 8 made in the stationary blade 6 so as to 
give a freedom to the stationary blade 6. 
In the above described embodiment, the flange parts 17 are made to have a 
lengthwise direction coinciding with the sliding direction of the movable 
blade 7 and are holding with their lower surfaces the upper surfaces of 
the front and rear peripheral edge portions of the fitting holes 8 to fix 
the blade block 3. Now, in the case of sweeping cut hair X or the like 
entered between the movable blade 7 and the stationary blade 6, the 
fitting pins 16 as fitted in the holes are rotated by 90 degrees to have 
the lengthwise direction of the flange parts 17 positioned to intersect at 
right angles the sliding direction of the movable blade 7. Thus the 
lengthwise direction of the flange parts 17 will coincide with the major 
diameter of the fitting holes 8, the flange parts 17 are allowed to pass 
through the fitting holes 8 to render the stationary blade 6 capable of 
being pulled out but, on the other hand, as the lengthwise direction of 
the flange parts 17 are intersecting at right angles the sliding direction 
of the movable blade 7, the lower surfaces of both end portions in the 
lengthwise direction of the flange parts 17 are caused to engage the upper 
surfaces of both side edges of the sliding holes 11 formed in the movable 
blade 7 and the movable blade 7 is caused to engage the flange parts 17 of 
the fitting pins 16, whereby the movable blade and push-up means 14 are 
prevented from being dismounted from the base 4. In dismounting the 
movable blade 7 and push-up means 14 from the base 4, the fitting pins 16 
are further rotated by 90 degrees from the above state to have the 
lengthwise direction of the flange parts 17 again coincided with the 
sliding direction of the movable blade 7. 
FIGS. 9 to 13 are views of an embodiment of an attachment detachably fitted 
to the electric shaver to improve the easiness in use of the electric 
shaver, wherein a guide projection 21, guide groove 22, positioning recess 
23 and positioning projection 24 are formed respectively in an attachment 
20, blade holder 2 and base 4 to protect the blades and prevent any 
rattling of the attachment. The attachment shown in FIGS. 9 and 10 
comprises a mounting part 25 curved into a U-shape for being detachably 
fitted to the blade holder 2 and blade block 3, and a plate-shaped guide 
part 26 formed integrally with one side of the U-shape mounting part and 
projected close to an extension of line D connecting a tip of the mounting 
part 25 and the stationary blade 6. When the attachment 20 is fitted to 
the electric shaver, the shaver is to be used while pressing the user's 
skin surface naturally to the shaver on the line D connecting the tip 27 
of the guide part 26 of the attachment 20 and the tip 28 of the stationary 
blade 6, so that no possibility of using the stationary blade 6 applied at 
right angles with respect to the skin surface will arise and any unskilled 
user will be able to well use the shaver. The cut hair will be deposited 
in a clearance between the stationary blade 6 and the guide part 26 of the 
attachment 20 and the hairs will not scatter. Since this attachment 20 is 
detachably mounted to the electric shaver, the use may be made with the 
attachment 20 detached in the event of shaving any odd hair on the hair 
growing boundary or the like so that hair trimming will be performed 
easily. In the case where the attachment is attached to the electric 
shaver having both of the long blade 10 and short blade 9, a safe use can 
be achieved while either one of the long blade and short blade is being 
used, without causing hair to be cut excessively or the skin to be hurt 
with the other blade. 
The attachments shown in FIGS. 11 to 14 comprise a U-shaped sheath part 29 
opened along one side to be detachably attached to the blade holder 2 and 
blade block 3 and a pair of comb-shaped tooth parts 30 extending from both 
edges of the opened side beyond the stationary blade 6 along the outer 
faces of the stationary blade 6. In case the distances l.sub.1 and l.sub.2 
between respective side faces of cutting blade part 31 formed of the 
stationary blade 6 and movable blade 7 and respective skin contacting 
surfaces 32 of the comb-shaped tooth parts 30 are made equal to each other 
on both sides of the cutting blade part 31, hair can be sheared at a 
uniform height even if either of surfaces C and D of the attachment 20 is 
applied to the skin. When the attachment 20 is made asymmetrical on both 
sides of the opening 33 and the heights l.sub.1 and l.sub.2 of the 
comb-shaped tooth parts 30 of the attachment 20 are made different from 
each other on both sides of the cutting blade part 31 as in FIG. 13, the 
shaving height will be different between the respective cases when the 
surface C of the attachment 20 is applied to the skin and when the surface 
D is applied to the skin, so that an action of replacing the attachment 
whenever the shaving height must be changed can be omitted and the shaver 
will be used conveniently. In the attachment shown in FIG. 14, the 
distance l.sub.3 between the projection 33 of the comb-shaped tooth part 
30 of the attachment 20 and the tip of the cutting blade part 31 of the 
shaver is made the same as or larger than each of the shaving heights 
l.sub.1 and l.sub.2. Even if the skin surface is pressed against the 
projections by mistake, hair will not be shaved to be too short by 
mistake. 
In the electric shaver according to the present invention, as described 
above, the fitting pins rotatably urged into the fitting bosses on the 
base are formed in an elongated shape at the upper end flange parts and 
laterally extending fitting holes with the major diameter lying in the 
direction intersecting at right angles the sliding direction of the 
movable blade are formed in the stationary blade, so that there will be 
brought about such effects that, when the lengthwise direction of the 
flange parts is placed to intersect at right angles with the sliding 
direction, the flange parts will become free to be inserted through the 
fitting holes and the stationary blade can be dismounted independently of 
the other movable blade and push-up means while, when the lengthwise 
direction of the flange parts is made to coincide with the sliding 
direction, the lower surfaces of the flange parts will engage with the 
peripheral edges of the shorter sides of the fitting holes, whereby the 
blade block can be positively assembled, and only the stationary blade 
will be able to be independently dismounted so that the movable blade and 
push-up means will not be caused to be disassembled, and the blade block 
can be easily disassembled and assembled for sweeping deposited cut hair 
to allow such hair to be cleaned in simple manner.