Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
1057543
RIVET TYPE FASTENER
~his invention relates to a rivet type fastener which
is excellent in the force with which desired fastening of
given pieces is accomplished.
The conventional rivet type fastener has been composed
of a rivet-shaped female member comprising a flange-shaped
head formed at one end thereof and a shank containing therein
a blind hole opening at the top of said head and a slit
inserted from the other end of the shank through the bottom
of said blind hole so as to divide the shank into two equal
sectorial parts and a male member comprising a head portion
and a stem having a length greater than the depth of said
blind hole in the female member, whereby desired union of
t~o or more given pieces is accomplished by first passing
the shank of the female member through correctly registered
holes of a substantially equal diameter in said pieces, then
inserting the stem of the male member into the blind hole of
the female member via the opening of said blind hole and,
even after the leading end of the stem has reached the bottom
of the blind hole, continuing the insertion of the stem for
thereby causing the forward portions of the sectorial parts
of said shank of the female member to be pushed open di-
vergently and enabling the divergently expanded portions of
the sectorial parts to provide perfect coupling of the male
and female members and, at the same time, precluding the
coupled members from slipping out of the registered holes of
said pieces.
In the case of the rivet type fastener of such a con-
ventional principle, the depth of the blind hole, the diameter
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of the stem, etc. of the female member are not allowed to
have any appreciable variation with reference to the thick~
nesses of the pieces given to be fastened and the diameters
of the registered holes in such pieces. If the combined
thickness of the pieces being fastened with this rivet type
fastener happens to be smaller or greater than the depth of
the blind hole in the female member, for example, then the
force with which this fastener binds the pieces together is
too weak to provide the expected effect.
An object of the present invention is to provide a
rivet type fastener which fairly wide tolerance with respect
to variations in thicknesses of pieces being fastened and
diameters of holes bored in such pieces, enables the pieces
to be fastened with great force and yet possesses a structure
capable of providing easy release of the pieces from the
union.
To accomplish the object described above according to
the present invention, there is provided a rivet type fastener
which is composed of a female member and a male member, said
female member comprising a flange provided with two pairs of
downwardly extended opposed walls of which the opposed walls
in one pair incorporate inclined cams on the undersides there-
of and a shank containing in the basal portion thereof a blind
hole opening at the top of said flange and divided in the
forward portion thereof into equal sectorial parts by radial
slits and said male member comprising a head portion provided
at the outer periphery thereof with two pairs of downwardly
extended, opposed arcuate walls of which the opposed arcuate
walls in one pair have inwardly projecting catches formed
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one each at the lower ends thereof and an operating stem
extended downwardly from the center of the underside of said
head portion, whereby the mutual union of the male and
female members of this fastener which serves the purpose of
fastening given pieces in position is accomplished by causing
the catches of the male member to come into engaging contact
with the inclined cams on the downwardly extended walls of
the female member.
The shank of the female member is passed through regis-
tered holes in the given pieces. Then, into the blind hole
of the female member, the operating stem of the male member
is inserted and driven home. Since the operating stem has a
length greater than the depth of the blind hole in the female
member, it penetrates beyond the bottom of the blind hole by
widening the intervening radial slits and divergently opening
the divided sectorial parts of the shank of the female member.
Consequently, the divergently expanded sectorial parts of the
shank are pressed so tightly against the edges of the holes
in said pieces that the fastener will not be released through
said holes. The catches formed at the leading ends o the
pair of downwardly extended arcuate walls of the male member
for the purpose of preventing the operating step of the male
member from being released through the holes in the pieces
come into engaging contact with the lower surfaces of the
downwardly extended walls of the flange of the female member.
Now, by rotating the male member alone about its axis relative
to the female member, the catches while sliding on the tapered
surfaces of the flange of the female member gradually draw the
female member thereto. Consequently, the force with which
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this fastener holds the pieces in their joined position can
freely be adjusted by controlling the rotation of the male
member relative to the female member. As described above,
the present invention provides a rivet type fastener which
permits the given pieces to be joined with a proper amount
of fastening force and, at the same time, has fairly wide
tolerance to variations in the thickness of pieces being
joined and diameters of holes bored in such pieceg.
The other objects and characteristics of the present
invention will become apparent from the detailed description
of the invention to be given hereinafter with reference to
the accompanying drawing.
Figure 1 is a perspective view of one preferred embodi-
ment of the rivet type fastener according to the present
invention.
Figures 2a through 2d illustrate the female member of
the rivet type fastener of Fig. 1 respectively in top plan
view, bottom plan view, wide view and sectioned view taken
along the d-d line of Fig. 2a.
Figures 3a and 3b illustrate the male member of the
rivet type fastener of Fig. 1 respectively in bottom plan
view and sectioned view taken along the b-b line of Fig. 3a.
Figures 4a through 4c are longitudinally sectioned side
views for showing the condition in which the male and female
members of the rivet type fastener of Fig. 1 are brought into
assembly, respectively illustrating the two members held in
a provisionally assembled state, in a completely assembled
state and in a state in which the fastening force exerted by
the fastener is increased in consequence of the rotation of
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the male member relative to the female member.
Figure 5 is a partially cutaway perspective view of
another preferred embodiment of the female member of the
rivet type fastener according to the present invention.
Figure 6 is a side view of still another preferred
embodiment of the female member of the rivet type fastener
according to the present invention, appearing with Figures
3a, 3b, 4a, 4b, and 4c.
Figure 7 is a longitudinally sectioned side view
illustrating the rivet type fastener in a state provisionally
assembled by use of the female member of Figure 6.
~igures 8a and 8b show yet another preferred embodiment
of the female member of the rivet type fastener according to
the present invention, respectively in a plan view and in a
longitudinally sectioned side view.
~eference is made to the drawing. The rivet type
fastener of the present invention is composed of the two
essential components, i.e. a male member 1 and a female
member 11 both made of a plastic material possessed of a
suitable degree of elasticity, and is effectively used in
fastening panels and other similar pieces inaccessible from
the rear side.
The female member 11 has a shank 12 of the shape of a
round rod. This shank 12 has disposed along the axis thereof
a blind hole 13 opening at one end of the shank 12. From the
other end of the shank 12 through the bottom of said blind
hole 13, a slit 14 is inserted to sever that portion of the
shank into two substantially equal sectorial parts 15a and
15b (Fig. 2d). It naturally permissible to increase the
number of (radial) slits thus inserted in the shank so as to
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form three, four or more sectorial parts.
At the end at which said blind hole 13 opens, the female
member 11 is provided with an outwardly extended flange 16.
In the preferred embodiment illustrated in Fig. 2a, the
flange 16 consists of four substantially quadrant portions
symmetrically arranged with reference to the center of said
blind hole 13, with the opposed quadrant portions in one
pair 17 having a greater diameter than those of the other
pair 18. The quadrant portions 17 of the greater diameter
each possesses a downwardly extended wall 17' of a height
which is smaller by approximately the combined thickness of
pieces being fastened than the depth of the blind hole 13.
The quadrant portions 18 of the smaller diameter each possess
a downwardly extended wall 18' having a height smaller than
that of said downwardly extended walls 17'. The downwardly
extended walls 18' of the quadrant portions 18 are each
provided on about half the entire length of the outer surface
thereof with a tapered surface 16' in such a way that the two
tapered surfaces are positioned in a symmetrical relationship
with reerence to the center o the blind hole 13. While the
undersides of the parts of the downwardly extended walls 18'
containing the tapered surfaces 16' are parallel to the upper
surface of the flange 16, the undersides of the parts of said
downwardly extended walls 18' not containing the tapered
surfaces 16' are shaped so that they form inclined cams 19 of
slanted surfaces which reach their peaks where they run into
the downwardly extended walls of the quadrant portions 17 of
the greater diameter.
The male member 1 designed to be coupled with the female
1057543
member 11 of the construction described above ~omprise~ a
head portion 2 having an inside diameter greater than the
diameter of the flange 16 of the female member 11 and an
operating stem 3 which is extended downwardly from the
center of the underside of said head portion 2. Said
operating stern 3 in the shape of a round bar has a height
greater than the depth of the blind hole 13 of the female
member 11 and a diameter substantially equal to the inside
diameter of the blind hole. In this preferred embodiment,
the male member is provided along the circumference of the
head portion 2 thereof with two first downwardly extended
arcuate walls 7 subtending an angle of 120 and opposed
symmetrically to each other with reference to the center of
the head portion. The first arcuate walls 7 have a length
slightly greater than the length which the downwardly ex-
tended walls 17' of the quadrant portions 17 of the greater
diameter in the female member assume when the male and
female members of the fastener are brought into a coupled
state. From the portions of the circurnference of the head
portion 2 in which the first arcuate walls 7 are totally
absent, there are downwardly extended second arcuate walls 8
which are provided at the free ends thereof with inwardly
projecting catches 5. The catches 5 are adapted so as to be
brought into engaging contact with the lower surfaces of the
downwardly extended walls 18' of the quadrant portions 18 of
the female member when the male and female members are put
into a coupled state. To ensure ease of the engagement with
the female member, the catches have the lower corners 6 of
their leading ends rounded smoothly. Although these second
10~;7543
arcuate walls 8 may be formed and disposed continuously with
the first arcuate walls 7 throughout the entire circumference
of the head portion of the male member, it is nevertheless
more advantageous for the two pairs of the arcuate walls to
5 be disposed separately of each other so that the second
arcuate walls enjoy more flexibility and, consequently, the
catches extending from these second arcuate walls may be
brought into engagement more readily with the undersides of
the downwardly extended walls 18' of the quadrant portions
18 of the smaIler diameter in the female member. The openings
4 are indispensable elements for the purpose of forming
catches of a complicated structure in the one-shot injection
molding of the male member with a plastic material. Owing to
the inclusion of these openings 4 in the male member, the
metal die required for the injection molding can be simply
fabricated in a horizontally split two-piece construction.
As will be described in further detail afterward, after the
male and female members are brought into a coupled state,
the male member alone is rotated about its axis relative to
the female member so as to add all the more to the fastening
force to be exerted by the fastener upon the pieces heing
united. During the rotation of the male member, the openings
4 prove quite convenient in the sense that they permit
insertion of proper tools such as, for example, pin-face
drivers which greatly facilitate the work of rotation. As an
aid for smooth rotation of the male member, it may be ad-
visable to have knurls 9 formed on the outer surface of the
first arcuate walls of the male member.
Now, a case in which two pieces 21, 22 given to be
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1057543
joined with each other are fastened in position by use of
the rivet type fastener composed of the male and female
members of the aforementioned constructions will be described.
Fig. 4a depicts the first step to be taken in fastening
the two pieces. Specifically, the operating stem 3 of the
male member is inserted into the blind hole of the female
member and the shank of the female member is passed through
registered holes 23 in the pieces 21, 22. The two actions
involved here may be either in the order mentioned above or
in the reversed order, whichever proves convenient for the
occasion. In this case, the insertion of the operating stem
3 of the male member in said blind hole 13 of the female
member is stopped when the leading end of said stem collides
into the bottom of the blind hole. At the same time, the
catches 5 of the male member are brought to positions
opposite the tapered surfaces 16' of the downwardly extended
walls 18' of the female member. Thus, the male and female
members assume a provisionally assembled state in consequence
of the first step described above.
The second step consists in exerting an added force upon
the male member 1 for thereby causing the leading end of the
operating stem of the male member which has already advanced
to the bottom of the blind hole of the female member to be
driven further into the female member ll. As the result,
the catches of the male member are twisted outwardly and, at
the same time, are caused to slide down the tapered surfaces
16' of the downwardly extended walls of the quadrant portions
of the smaller diameter of the female member and eventually
come to rest beneath the lower surfaces of the downwardly
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1057543
extended walls 18' of said quadrant portions, briging the
male and female members into complete coupling. In the
meantime, the operating stem 3 of the male member which has
been held inside the blind hole of the female member is
caused to pierce through the bottom of the blind hole, with
the result that the sectorial parts 15a, 15b of the shank 12
of the female member split by the slit 14 are pushed open
divergently and pressed so strongly against the edges of the
registered holes 23 in the pieces 21, 22 that the shank 12
cannot slip through said registered holes 23.
Depending on the combined thickness of the pieces being
fastened and the diameter of the registered holes in such
pieces, the two steps of operation described above may alone
prove sufficient for providing desired fastening of the two
pieces. In case where the pieces are desired to be fastened
with a greater force or where the combined thickness of the
pieces being fastened and the diameter of the registered
holes in the pieces are more or less inappropriate so that
the two steps of operation fail to provide sufficient fastening
of the pieces, the third step illustrated in Fig. ~c will gi~e
a solution. To be specific, the third step consists in causing
the catches 5 which have been brought into engaging contact
with the lower surfaces of the downwardly extended walls 18'
located at the tapered surfaces 16' of the quadrant portions
of the smaller diameter in the female member in consequence
of the second step of operation to be moved to the inclined
surfaces of the inclined cams 19 underneath the downwardly
extended walls 18'. This movement of the catches to the new
positions results in a decrease in the distances from the
1057543
divergently spread and internally swelled portions of the
sectorial parts 15a, 15b now keeping in tight union the two
pieces 21, 22 to the lower surfaces of the first arcuate
walls 7 of the male member. Consequently, the fastening
force exerted by the fastener upon the pieces is proportio-
nally increased. This step of moving the catches to said
new positions can be effected by rotating the male member
alone relative to the female member. By this rotation, the
catches of the male member which slide along the tapered
surfaces 19 of the female member can be moved laterally
until they collide into the stepped portions formed where
the quadrant portions of the greater diameter and those of
the smaller diameter respectively of the female member meet.
By regulating the rotation of the male member, the fastening
force exerted on the pieces can be increased or properly
adjusted. This particular step of operation can be expected
to provide a great effect in the desired fastening of pieces.
After the catches of the male member have been brought
to the peak points of the tapered surfaces of the female
member in consequence of said rotation of the male member,
there is still a possibility that vibration or some other
similar external shock will cause the catches to slide back-
wardly on the tapered surfaces even to the extent of loosening
the union. As a preventive measure, stop notches 20 may be
provided at the peak section of the tapered surfaces as
illustrated in Fig. 2c, so that the rotation of the male
member causes the catches to fall into these stop notches.
With the catches thus held tightly in the stop notches, the
aforementioned possibility of loss of tight union between the
:1057S43
male and female members is totally eliminated.
As concerns the rotation of the male member described
above, if the pieces given to be fastened are in the shape
of panels and do not permit direct access to the rear sides
thereof, there is a possibility that the rotation of the male
member may cause the female member to rotate simultaneously.
To preclude the unwanted rotation of the female member, the
shank 12' of the female member may be shaped in a square
cross section and the holes 24 in the pieces 21, 22 may be
shaped also in a square conforming to the cross section. By
having the shank 12' and the holes 24 of pieces shaped as
described above, the work otherwise required to be done on
the rear side of panels can be dispensed with. Fig. 5 merely
depicts one example. The shank and the holes in the pieces
being fastened may be shaped in any desired form other than
a circle. To facilitate the divergent spread of the leading
portion of the shank, it is advantageous that the number of
radiant slits inserted to divide said leading portion of the
shank into sectorial parts should be properly increased.
Fig. 6 represents another preferred embodiment of the
female member in the rivet type fastener according to the
present invention. This female member has a structure which
is devoid of the tapered surfaces 16' involved in the pre-
ferred embodiment of Fig. 2c. In the fastener of the former
preferred embodiment, the male and female members in their
provisionally assembled state (Fig. 4a) are not positively
fastened to each other. If they are left to stand in this
provisionally assembled state while the fastener is not in
use, vibration or some other similar external shock may
1057S43
possibly cause them to separate from each other. Generally,
therefore, the two members are stored in their separated
state. From the standpoint of the management of parts,
however, storage of the two members in their separated s*ate
does not prove advantageous. The preferred embodiment of
Fig. 5 has an advantage that the female member permits the
catches of the male member to be directly secured onto the
lower edge of the flange of the female member so that the
male and female members will be stored intact in their pro-
visionally assembled state (Fig. 7).
In the preferred embodiment of Figs. 8a, 8b, the wallsdownwardly extended from the quadrant portions of the greater
diameter and those downwardly extended from the quadrant
portions of the smaller diameter of the female member as seen
in Fig. 2 are so disposed that their outer peripheries fall
in one and the same circumference. Despite the varied dis-
position, these walls fulfil the same function as those
illustrated in Fig. 1. In this particular preferred embodi-
ment, the male member illustrated in Figs. 3a, 3b may be used
effectively. In that case, the male and female members may
be shaped so that the outside diameter of the female member
equals the inside diameter of the first and second arcuate
walls of the male member. This modification promises com-
paction and simplification of the constructions of these two
members.
As described above, the rivet type fastener of the
present invention permits a proper adjustment to be given to
the relative positions of the male and female members which
are coupled to provide desired fastening of the pieces.
l~S7543
Thus, the fastener also permits proper selection of the
fastening force to be exerted upon the pieces and, at the
same time, tolerates fairly wide variations in the combined
thickness of the pieces being fastened and the diameter of
the registered holes in such pieces. Uses found for the
rivet type fastener of the present invention can be further
increased by attaching another suitable fastener means to
the male member thereof.
