GB2183711A

GB2183711A - Stud and socket fastener

Info

Publication number: GB2183711A
Application number: GB08526586A
Authority: GB
Inventors: David Brindle
Original assignee: TEE BEE PRODUCTS
Current assignee: TEE BEE PRODUCTS
Priority date: 1985-10-29
Filing date: 1985-10-29
Publication date: 1987-06-10
Also published as: GB8526586D0

Abstract

A fastener includes a first part in the form of a stud the shank 2 of which is formed with a spigot 3, and a second part which is also in the form of a stud 4, the shank 5 of which is formed with an internal socket 6. The shank 5 of the stud 4 is pushed through the layers of materials to be joined, and the spigot 3 of the stud 1 is then engaged into the socket 6 and pushed therein a little way, by hand. Thereafter the stud 1 is pressed fully home by use of a suitable tool such as a pair of pliers or by hammering one of the studs home until the spigot 3 is fully engaged within the socket 6, when a shoulder 9 abuts a flared mouth 13 of the socket. <IMAGE>

Description

SPECIFICATION Fasteners This invention relates to fasteners, and is concerned particularly with two-part fasteners having a press-fit action.

We are aware of a two-part fastener for use in fastening a plastics mesh into a rubbersurround-for example, for use in mudflapsforwagonsorlorrys.

The known fastener comprises two identical parts, each comprising a pair of parallel spaced arms of right angled quadrant section, disposed diametrically opposite one another. The arms are internally serrated and encircled at their base by a separate collar. In use, the two parts are disposed opposite one anotherwith the arms of one part angularlydis- posed by 90 degrees from those of the other part.

The two pairs of arms are then interengaged, until the free ends of each pair of arms engage within the collaratthe base ofthe other pair ofarms.Theser- rations interlock, to inhibit withdrawal of the two parts from one another.

A disadvantage of such a fastener is that, when twisted, the arms tend to disengage. Also, the time taken to manufacture each part comprises a significant portion forfitting the collar around the arms.

Preferred embodiments ofthe present invention aim to mitigate these disadvantages.

According to one aspect of the present invention, there is provided a fastener comprising a first part formed with a spigot and a second partformedwith a socket to receive the spigot, the outer surface of the spigot and the inner surface of the socket being formed with complementary interengaging portions such thatthe first and second parts may be secured together as a press fit, with the spigot engaging in the socket and said portions interengaging to inhibit withdrawal ofthe spigot from the socket.

Said complementary interengaging portions may comprise annular ridges formed on one of said surface, and annular grooves formed on the other of said surfaces. Preferably, such ridges and/or grooves are of a barbed configuration.

In a preferred arrangement, said outer surface of the spigot is formed with barbed annular ridges and said inner surface of the socket is formed with annular grooves to receive the ridges.

Each of said parts is preferably moulded as a single piece from plastics material.

Each of said parts is preferably formed as a stud, said socket being formed in a shank of a respective one of the studs. Each such stud may be formed with a domed head.

Preferably, the mouth of said socket is flared, to facilitate introduction of the spigot.

Four a better understanding of the invention and to show howthe same may be carried into effect, referpence will now be made, byway of example, tothe accompanying diagrammatic drawing, the single figure of which is a longitudinal section of a two-part fastener embodying the invention.

The fastener that is shown in the drawing comprises afirst part in theform of a stud 1 the shank 2 of which is formed with a spigot3, and a second part which is also in the form of a stud 4, the shank 5of which isformedwith an internal socket 6. Both ofthe studs 1, 4 are formed as one piece mouldings, of plastics material.

The stud 1 has a domed head 7, and its shank 2 has a first portion 8 of relatively large diameter, and a second portion of smaller diameter, which defines the spigot 3. A chamfered shoulder 9 joins thefirst shank portion 98with the spigot 3. The spigot 3 is formed with a series of six annular ridges 10, each of which is oftriangular section, in the manner of a barb.

The stud 4 also has a domed head 11. The inner surface of the socket 6 is formed with a series of annular grooves 12, adapted to cooperate with the ridges 10. The mouth 13 ofthe socket 6 is flared.

The studs 1,4 may be used to fasten a plastics mesh into a rubbersurround-forexample, as in lorry mud flaps. To this end, the shank 5 of the stud 4 may be pushed through the layers of materials to be joined. The spigot 3 of the stud 1 is then engaged into the socket 6, and pushed therein a little way, by hand.

The flare mouth 13 of the socket 6 assists the introduction ofthe spigot 3 therein. Thereafter, the stud 1 is pressed fully home until the spigot3 is fully engaged within the socket 6, when the shoulder 9 abuts the flare mouth 13.

As the spigot is pushed into the socket 6, the barbed ridges 10 resiliently engage within the correspondingly shaped grooves 12, such that the two studs 1,4 interengaged as a press-fit. The shape of the ridges loins such as to permit introduction of the spigot 3 readily into the socket 6, but inhibitwith- drawal thereof.

The closeness of fit of the spigot 3 in the socket 6 may be such that the spigot may be introduced into the socket only a limited way by hand, the remaining travel being forced by means of a suitable tool -for example a pair of pliers or, if one of the studs is supported at its head, by hammering the other stud home.

Where a plurality of fasteners are to be fitted, the studs 4may be fitted into the layers of material to be joined, as outlined above, and the studs 1 engaged lightly therein, by hand. Thereafter, the studs may be hammered home, either individually, or in groups, by means of a blow applied to a bar which engages all ofthe heads 7 simultaneously.

It is not essential thatthe grooves 12 have the same configuration as the ridges 11. Forexample, the grooves 12 may be part-circular in section.

The invention is not restricted to the details of the foregoing embodiment(s). The invention extends two any novel one, or any novel combination, of the fea- tures disclosed in this specification and/or drawings, orto any novel one, or any novel combination, of the steps of any method or process disclosed therein.

1. A fastener comprising a first part formed with a spigot and a second part formed with a socket to receive the spigot, the outersurface of the spigot and the inner surface of the socket being formed with complimentary engaging portions such that the first

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION Fasteners This invention relates to fasteners, and is concerned particularly with two-part fasteners having a press-fit action. We are aware of a two-part fastener for use in fastening a plastics mesh into a rubbersurround-for example, for use in mudflapsforwagonsorlorrys. The known fastener comprises two identical parts, each comprising a pair of parallel spaced arms of right angled quadrant section, disposed diametrically opposite one another. The arms are internally serrated and encircled at their base by a separate collar. In use, the two parts are disposed opposite one anotherwith the arms of one part angularlydis- posed by 90 degrees from those of the other part. The two pairs of arms are then interengaged, until the free ends of each pair of arms engage within the collaratthe base ofthe other pair ofarms.Theser- rations interlock, to inhibit withdrawal of the two parts from one another. A disadvantage of such a fastener is that, when twisted, the arms tend to disengage. Also, the time taken to manufacture each part comprises a significant portion forfitting the collar around the arms. Preferred embodiments ofthe present invention aim to mitigate these disadvantages. According to one aspect of the present invention, there is provided a fastener comprising a first part formed with a spigot and a second partformedwith a socket to receive the spigot, the outer surface of the spigot and the inner surface of the socket being formed with complementary interengaging portions such thatthe first and second parts may be secured together as a press fit, with the spigot engaging in the socket and said portions interengaging to inhibit withdrawal ofthe spigot from the socket. Said complementary interengaging portions may comprise annular ridges formed on one of said surface, and annular grooves formed on the other of said surfaces. Preferably, such ridges and/or grooves are of a barbed configuration. In a preferred arrangement, said outer surface of the spigot is formed with barbed annular ridges and said inner surface of the socket is formed with annular grooves to receive the ridges. Each of said parts is preferably moulded as a single piece from plastics material. Each of said parts is preferably formed as a stud, said socket being formed in a shank of a respective one of the studs. Each such stud may be formed with a domed head. Preferably, the mouth of said socket is flared, to facilitate introduction of the spigot. Four a better understanding of the invention and to show howthe same may be carried into effect, referpence will now be made, byway of example, tothe accompanying diagrammatic drawing, the single figure of which is a longitudinal section of a two-part fastener embodying the invention. The fastener that is shown in the drawing comprises afirst part in theform of a stud 1 the shank 2 of which is formed with a spigot3, and a second part which is also in the form of a stud 4, the shank 5of which isformedwith an internal socket 6. Both ofthe studs 1, 4 are formed as one piece mouldings, of plastics material. The stud 1 has a domed head 7, and its shank 2 has a first portion 8 of relatively large diameter, and a second portion of smaller diameter, which defines the spigot 3. A chamfered shoulder 9 joins thefirst shank portion 98with the spigot 3. The spigot 3 is formed with a series of six annular ridges 10, each of which is oftriangular section, in the manner of a barb. The stud 4 also has a domed head 11. The inner surface of the socket 6 is formed with a series of annular grooves 12, adapted to cooperate with the ridges 10. The mouth 13 ofthe socket 6 is flared. The studs 1,4 may be used to fasten a plastics mesh into a rubbersurround-forexample, as in lorry mud flaps. To this end, the shank 5 of the stud 4 may be pushed through the layers of materials to be joined. The spigot 3 of the stud 1 is then engaged into the socket 6, and pushed therein a little way, by hand. The flare mouth 13 of the socket 6 assists the introduction ofthe spigot 3 therein. Thereafter, the stud 1 is pressed fully home until the spigot3 is fully engaged within the socket 6, when the shoulder 9 abuts the flare mouth 13. As the spigot is pushed into the socket 6, the barbed ridges 10 resiliently engage within the correspondingly shaped grooves 12, such that the two studs 1,4 interengaged as a press-fit. The shape of the ridges loins such as to permit introduction of the spigot 3 readily into the socket 6, but inhibitwith- drawal thereof. The closeness of fit of the spigot 3 in the socket 6 may be such that the spigot may be introduced into the socket only a limited way by hand, the remaining travel being forced by means of a suitable tool -for example a pair of pliers or, if one of the studs is supported at its head, by hammering the other stud home. Where a plurality of fasteners are to be fitted, the studs 4may be fitted into the layers of material to be joined, as outlined above, and the studs 1 engaged lightly therein, by hand. Thereafter, the studs may be hammered home, either individually, or in groups, by means of a blow applied to a bar which engages all ofthe heads 7 simultaneously. It is not essential thatthe grooves 12 have the same configuration as the ridges 11. Forexample, the grooves 12 may be part-circular in section. The invention is not restricted to the details of the foregoing embodiment(s). The invention extends two any novel one, or any novel combination, of the fea- tures disclosed in this specification and/or drawings, orto any novel one, or any novel combination, of the steps of any method or process disclosed therein. CLAIMS

1. A fastener comprising a first part formed with a spigot and a second part formed with a socket to receive the spigot, the outersurface of the spigot and the inner surface of the socket being formed with complimentary engaging portions such that the first and second parts may be secured together as a press fit, with the spigot engaging in the socket and said portions interengaging to inhibit withdrawal ofthe spigot from the socket.

2. Afastener as claimed in claim 1 in which said complimentaryinterengaging portionscomprisean- nularridgesformed on one of said surfaces, and annular grooves formed on the other of said surfaces.

3. Afastener as claimed in claim 2 in which said ridges are of barbed configuration.

4. Afasteneras claimed in claim 2 or 3 in which said grooves are of a barbed configuration.

5. Afasteneras claimed in claim 2 and claim 3 or as claimed in claim 2,3 and 4 in which said outer surface ofthe spigot is formed with barbed annular ridges and said inner surface of the socket is formed with annular grooves to receive the ridges.

6. A fastener as claimed in any preceding claim in which each of said parts are moulded as a single piece from plastics material.

7. Afastener as claimed in any preceding claim in which each of said parts is formed as a stud, said socket being formed in a shank of respective one of the studs.

8. Afastener as claimed in claim 7 in which each stud isformedwith a domed head.

9. A fastener as claimed in any preceding claim in which the mouth of said socket is flared, to facilitate introduction ofthe spigot.

10. Afastener as claimed in any preceding claim in which the first and second parts are secured together with the spigot engaging in the socket and said portions interengaging to inhibit withdrawal of the spigot from the socket.

11. Afastenerincluding afirstpartand/ora second part substantially as herein described with reference to, and as shown in the accompanying drawing.

12. Amethod ofconnecting a first part and a second part of a fastener as claimed in any preceding claim comprising using a tool to force the spigot of the first part into engagementwith the socket of the second part.

13. A method as claimed in claim 12 comprising engaging the spigot of the first part with the socket of the second part lightly by hand priorto using the tool.

14. A method of connecting a first and a second part of a fastener substantially as herein described with reference to, and as shown in the accompany ingdrawing.