CA1057543A - Rivet type fastener - Google Patents
Rivet type fastenerInfo
- Publication number
- CA1057543A CA1057543A CA287,161A CA287161A CA1057543A CA 1057543 A CA1057543 A CA 1057543A CA 287161 A CA287161 A CA 287161A CA 1057543 A CA1057543 A CA 1057543A
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- female member
- type fastener
- walls
- male
- rivet type
- Prior art date
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Abstract
ABSTRACT OF THE DISCLOSURE
Disclosed herein is a rivet type fastener composed of a female member and a male member, said female member com-prising a shank containing a blind hole in the basal portion and divided by radial slits into two or more sectorial parts in the forward portion and a flange provided with two pairs of downwardly extended opposed walls of which the opposed walls in one pair incorporate inclined cams one each on the undersides thereof and said male member comprising a head portion provided on the outer periphery thereof with a down-wardly extended arcuate wall incorporating therein inwardly projecting catches adapted to permit engaging contact with said inclined cams of the female member and an operating stem having a length greater than the depth of said blind hole in the female member, whereby the mutual union of the male and female members which serves to fasten given pieces in position is accomplished with added fastening force by allowing said catches of the male member to come into engaging contact with said inclined cams of the female member and subsequently rotating the male member around its axis relative to the female member.
Disclosed herein is a rivet type fastener composed of a female member and a male member, said female member com-prising a shank containing a blind hole in the basal portion and divided by radial slits into two or more sectorial parts in the forward portion and a flange provided with two pairs of downwardly extended opposed walls of which the opposed walls in one pair incorporate inclined cams one each on the undersides thereof and said male member comprising a head portion provided on the outer periphery thereof with a down-wardly extended arcuate wall incorporating therein inwardly projecting catches adapted to permit engaging contact with said inclined cams of the female member and an operating stem having a length greater than the depth of said blind hole in the female member, whereby the mutual union of the male and female members which serves to fasten given pieces in position is accomplished with added fastening force by allowing said catches of the male member to come into engaging contact with said inclined cams of the female member and subsequently rotating the male member around its axis relative to the female member.
Description
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 ,~ ~
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 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 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 ~057543 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 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 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 _ g _ 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 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 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 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.
~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 ,~ ~
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 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 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 ~057543 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 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 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 _ g _ 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 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 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 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.
Claims (8)
1. A rivet type fastener composed of a female member and a male member, said female member comprising a flange provided with two pairs of opposed portions possessed of downwardly extended walls, the opposed portions in one pair having a greater diameter than those in the other pair and the downwardly extended walls of the pair of opposed portions of the smaller diameter being provided on the undersides thereof with inclined cams and a shank extended downwardly from the center of the lower surface of said flange, provided along the axis thereof with a blind hole opening at the top of said flange and also provided in the leading portion thereof with radial slits inserted from the leading end thereof through the bottom of said blind hole to divide that portion of the shank into equal sectorial parts, and said male member comprising a head portion provided along the outer periphery .
thereof with first and second pairs of opposed, down-wardly extended arcuate walls, the second arcuate walls being provided at the leading ends thereof with catches and an operating stem extended downwardly from the center of the lower surface of said head portion and having a height greater than the depth of said blind hole in the female member.
thereof with first and second pairs of opposed, down-wardly extended arcuate walls, the second arcuate walls being provided at the leading ends thereof with catches and an operating stem extended downwardly from the center of the lower surface of said head portion and having a height greater than the depth of said blind hole in the female member.
2. The rivet type fastener according to claim 1, wherein the walls downwardly extended from the portions of the smaller diameter of the flange in the female member are divided each into two halves and the halves and the halved walls in one of the two pairs symmetrically opposed with reference to the center of the female member are provided each with a tapered surface to facilitate insertion of the catches of the male member for eventual engaging contact.
3. The rivet type fastener according to claim 1, wherein stop notches adapted to maintain the catches of the male member in immovable contact are formed on the inclined cams provided on the lower surfaces of the downwardly extended walls of the portions of the smaller diameter in the female member.
4. The rivet type fastener according to claim 1, wherein knurls are formed on the outer surface of the first arcuate walls of the male member so as to facilitate the rotation of the male member relative to the female member.
5. The rivet type fastener according to claim 1, wherein the shank of the female member is shaped so as to have a circular cross section.
6. The rivet type fastener according to claim 1, wherein the shank of the female member is shaped so as to have a square cross section.
7. The rivet type fastener according to claim 1, wherein one of the two pairs of symmetrically opposed halved portions of the walls downwardly extended from the portions of the smaller diameter of the female member are removed.
8. The rivet type fastener according to claim 1, wherein the portions of the greater diameter and those of the smaller diameter of the female member are so disposed that their outer peripheries fall in one and the same circumference.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP11464176A JPS5854281B2 (en) | 1976-09-27 | 1976-09-27 | Rivet type fastener |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1057543A true CA1057543A (en) | 1979-07-03 |
Family
ID=14642877
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA287,161A Expired CA1057543A (en) | 1976-09-27 | 1977-09-21 | Rivet type fastener |
Country Status (2)
| Country | Link |
|---|---|
| JP (1) | JPS5854281B2 (en) |
| CA (1) | CA1057543A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4391559A (en) * | 1980-07-28 | 1983-07-05 | Nifco Inc. | Plastic fastener |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS6131534Y2 (en) * | 1981-06-23 | 1986-09-13 |
-
1976
- 1976-09-27 JP JP11464176A patent/JPS5854281B2/en not_active Expired
-
1977
- 1977-09-21 CA CA287,161A patent/CA1057543A/en not_active Expired
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4391559A (en) * | 1980-07-28 | 1983-07-05 | Nifco Inc. | Plastic fastener |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS5854281B2 (en) | 1983-12-03 |
| JPS5340154A (en) | 1978-04-12 |
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