GB2173851A

GB2173851A - Flex-action rivet for securing sheets together

Info

Publication number: GB2173851A
Application number: GB08608083A
Authority: GB
Inventors: Toshiya Ohkawa
Original assignee: Nifco Inc
Current assignee: Nifco Inc
Priority date: 1985-04-04
Filing date: 1986-04-02
Publication date: 1986-10-22
Also published as: KR910002322Y1; SE8601466D0; IT1213055B; JPH0135930Y2; ES293382U; KR860013537U; SE8601466L; GB8608083D0; IT8621443V0; BR8601515A; AU5564786A; JPS61166212U; IT8619988A0; SE466023B; GB2173851B; ES293382Y; NZ215686A

Abstract

A rivet comprises a female member having a flange (2) and a cylindrical portion depending from the flange (2) and divided by radially spaced-apart slits into plural divisions (4) and a male member having a large diameter portion (6) for holding the individual divisions (4) in radially outwardly flexed state, recesses (7, 8) provided above and below the large diameter portion (6) for holding the divisions (4) without flexing and stopper means (14) provided above the upper recess (8) for engaging with the upper surfaces of inward projections (5) of the divisions (4). When the male member is inserted into the female member from the Fig. 4 position, the divisions (4) of the cylindrical portion (1) are outwardly flexed by the large diameter portion (6). When the male member is further inserted, the divisions (4) restore to their initial state in the recess (8). The stopper means (14) prevents excessive insertion of the male member into the female member. <IMAGE>

Description

SPECIFICATION Flex-action rivet for securing sheets together This invention relates to a flexible rivet for releasably securing together a plurality of sheet-like articles, e.g. metal panels and printed circuit boards made of plastic etc., in an overlying state.

As a rivet of such type, there is well known a rivet which comprises an elastic female member having a cylindrical portion and a flange extending radially outwardly from the upper end of the cylindrical portion, the cylindrical portion being divided by a plurality of radially spaced-apart axial slits into a plurality of divisions, the divisions each having an inward projection extending radially inwardly from a lower end, and a male member inserted in the female member and having a large diameter portion having a peripheral annular groove, the inward projections of the divisions being capable of being trapped in the peripheral annular groove to hold the divisions radially outwardly flexed, the male member also having upper and lower recesses formed over and under the large diameter portion, respectively, the inward projections of the divisions being capable of being received in the upper and lower recesses without radially outward flexing of the divisions.

To secure together a plurality of sheets or the like in an overlying state with this rivet, the male and female members are first assembled together by inserting the former into the cylindrical portion of the latter such that the inward projections of the divisions of the latter are trapped in the lower recess under the large diameter portion of the former. In this state, the cylindrical portion of the latter is inserted through aligned holes of the overlaying sheets to bring the lower surface of the flange into engagement with the upper surface of the upper sheet. Then, the male member is further pushed into the female member until the inward projections of the divisions of the female member are trapped in the peripheral annular groove formed in the large diameter portion.In this state, the divisions of the female member are held radially outwardly flexed to urge the plurality of sheets against the lower surface of the flange with a cam action. The sheets are thus clamped together.

To release the sheets from the clamped state, the male member is further pushed into the female member. As a result, the inward projections of the divisions are trapped into a recess over the large diameter portion, and the divisions restore to the initial state due to their elasticity. Thus, both the members can be taken out of the holes of the sheets to release the sheets.

After the rivet has been taken out of the sheets, the male member is displaced relative to the female member in the take-out direction, bringing the inward projections of the divisions of the female member into engagement in the recess under the large diameter portion of the male member to be ready for repeated use for securing together sheets.

In the prior art rivet described above, the male member has a conical portion provided over the upper recess over the large diameter portion with upwardly increasing diameter.

Therefore, if the male member is excessively pushed into the female member to release the sheets, the inward projections of the divisions will ride on the conical portion so that they are again radially outwardly forced apart, making it impossible to release the sheets.

An object of the invention is to provide a rivet which prevents excessive insertion of the male member so that the divisions in an radially outwardly flexed state can reliably restore to their initial state.

According to the present invention, in the rivet of the type described, the male member is provided over the upper recess over the large diameter portion with stopper means which can engage upper surface of the inward projections of the divisions. With this construction, when the male member is further pushed into the female member to release the lock, the upper surfaces of the inward projections of its divisions eventually come into engagement with the stopper means of the male member, thus reliably preventing excessive insertion of the male member.

The above and other objects and features of the invention will become more apparent from the following detailed description of the accompanying drawings, in which: Figure 1 is an exploded perspective view showing an embodiment of the rivet according to the invention; Figure 2 is a bottom view showing a female member of the rivet according to the invention; Figure 3 is a sectional view taken along line Ill-Ill in Figure 1; Figure 4 is an axial sectional view showing female and male members of the rivet according to the invention in an assembled state; Figure 5 is a view similar to Figure 4 showing the rivet according to the invention securing sheets together; and Figure 6 is a view similar to Figure 4 showing the rivet according to the invention with the sheets released.

The drawings illustrate an embodiment of the rivet according to the invention. The illustrated embodiment comprises a female member A and a male member B. The female member A has a cylindrical portion 1 and a flange 2 having a shape like a suction disk.

The cylindrical portion 1 extends from the flange 2 and is formed with four axial slits 3 uniformly dividing it in the circumferential direction into four elastic divisions 4. The divi sions 4 each have an inward projection 5 projecting radially inwardly at the free end. The male member B has a large diameter portion 6 having a circumferential annular groove and tapering in the lower and upper directions to define respective recesses 7 and 8.

In this embodiment, the female and male members A and B are made of a plastic material. The male member B has a cylindrical upper portion 9 having a short axial dimension and a conical end portion 10. The intermediate portion between the portions 9 and 10 has fillets 11 defining a sectional profile of a cross and corresponding to the slits 3. The axis of the cross configuration arrangement of the fillets 11 coincides with the axes of the large diameter portion 6 and the recesses 7 and 8. The large diameter portion 6 is thus uniformly divided by the fillets 11 into four divisions each being found between adjacent fillets. The lower recess 7 is defined by an inverted conical portion 12, which extends between the end portion 10 and the lower end of the large diameter portion 6, and its diameter progressively increases toward the large diameter portion 6.The upper recess 8 is defined by a conical portion 13 which extends from the upper end of the large diameter portion 6. Its diameter reduces sharply away from the large diameter portion. Rib-like stoppers 14 extend from the lower end of the cylindrical upper portion 9 and between adjacent fillets 11. Their lower end is adapted to strike the upper or inner surface of the inward projections 5 of the divisions 4.

In use, the male member B is inserted into the cylindrical portion of the female member A from above. At this time the conical end portion 10 is brought into engagement with the inward projections 5 of the divisions 4, causing outward flexing of the divisions 4 as it passes through the lower end of the cylindrical portion. In consequence, the projections 5 are trapped in the recess 7, and the divisions 4 restore to their initial state due to their elasticity. In this state, the upper surface of the conical end portion 10 of the male member engages the projections 5 of the divisions to prevent the male member from being detached upwardly from the female member. The two members A and B are thus in an assembled state. In this state, relative rotation of the two members A and B is prevented by the engagement of the fillets 11 in the slits 3 defining the divisions 4.In this assembled state of the rivet, the cylindrical portion 1 of the female member A is inserted through aligned holes of a plurality of sheets (two sheets in this embodiment) C and D to be secured together (see Figure 4). The cylindrical portion 1 is inserted until the flange 2 is brought into contact with the upper surface of the upper sheet, and in this state the male member B is further pushed into the female member A. As the male member B is pushed in, its inverted conical portion 12 progressively outwardly forces apart the inward projections 5 of the divisions. The inward projections 5 are eventually trapped in the circumferential annular groove formed in the outer periphery of the large diameter portion 6, so that they are retained in this annular groove, as shown in Figure 5.In this state, the divisions of the cylindrical portion 1 are held outwardly flexed to urge the plurality of sheets against the lower surface of the flange 2. The sheets are thus clamped together between the urging portions of the outwardly flexed divisions 4 and the flange 2. In this state, the upper end of the male member is preferably flush with or slightly below the upper surface of the flange 2.

To release the clamped state of the sheets, the male member B is further pushed into the female member A. With this operation, the inward projections 5 of the divisions escape from the annular groove and become trapped in the upper recess 8, whereby the divisions 4 restore to their initial state due to their elasticity. At this time, the inward projections 5 come into engagement with the lower end of the stoppers 14 located above the recess 8 as shown in Figure 6. The male member thus can no longer be pushed into the female member, and the two members can be upwardly extracted through the aligned holes of the plurality of sheets to release the sheets.

The sharply tapering, inverted conical portion 13 extending from the upper end of the large diameter portion 6 of the male member serves to guide the inward projections of the divisions along it into the recess 8 when the male member is further pushed to release the sheets from the clamped state. In addition, when displacing the male member relative to the female member to return the initial assembled state for reuse of the rivet after it has been taken out, the inverted conical portion 13 also serves to permit the inward projections 5 to be forced apart and quickly clear the large diameter portion 6 without being trapped in the annular groove thereof. To this end, the inward projections 5 preferably have slantedly chamfered lower surfaces 5'.

As has been described in the foregoing, with the rivet according to the invention, once the inward projections 5 of the divisions 4 are trapped in the recess 8 with the male member pushed further to release the sheets from the clamped state, the stoppers 14 prevent the male member from being further pushed into the female member. Thus, there is no possibility that the divisions will be outwardly flexed once again due to excessive insertion of the male member so as to make it impossible to release the sheets.

Claims

1. A rivet comprising: an elastic female member having a cylindri cal portion and a flange extending radially outwardly from an upper end of said cylindrical portion, said cylindrical portion being divided by a plurality of radially spacedapart axial slits into a plurality of divisions, said divisions each having an inward projection extending radially inwardly from a lower end; and a male member for insertion in said female member and having a large diameter portion having a peripheral annular groove, the inward projections of said divisions being capable of being trapped in said peripheral annular groove to hold said divisions radially outwardly flexed, said male member also having upper and lower recesses formed over and under said large diameter portion, respectively, the inward projections of said divisions being capable of being received in said upper and lower recesses without radially outward flexing of said divisions; said male member further being provided over said upper recess over said large diameter portion with stopper means which can engage upper surfaces of said inward projections of said divisions.

2. A rivet according to claim 1, in which said male member has a plurality of axial fillets for engagement in respective ones of said axial slits, and has a plurality of rib-like stoppers extending between respective adjacent pairs of said axial fillets to constitute said stopper means.

3. A rivet substantially as herein described with reference to the accompanying drawings.