US2956468A - Plastic fastener with rounded expandable portion - Google Patents

Description

J. C. MACY Oct. 18, 1960 PLASTIC FASTENER WITH ROUNDED EXPANDABLE PORTION Filed April 19, 1956 2 Sheets-Sheet 1 INVENTOR.

J. C. MACY Oct. 18, 1960 PLASTIC FASTENER WITH ROUNDED EXPANDABLE. PORTION Filed April 19, 1956 2 Sheets-Sheet 2 INVENTOR.

VII/I/Il/AIIIIIVI/IM f Jam CL/ a y United States Patent Office Patented Oct. is, 1960 PLASTIC FASTENER WITH ROUNDED EXPANDABLE PORTION James C. Macy, Westfield, N.J., assignor to Illinois Tool Works, Chicago, 111., a corporation of Illinois Filed Apr. 19, 1956, Ser. No. 579,277

4 Claims. (Cl. 85-40) The present invention related to a novel device adapted to be applied to an apertured workpiece, and more particularly to a novel tubular device adaptable as used as a rivet, insulating bushing, bearing or the like.

An important object of the present invention is to provide a novel plastic device of the above described type which is of simplified construction and which may be relatively easily and securely applied to an apertured work structure.

A more specific object of the present invention is to provide a novel plastic device of the above described type that may be easily inserted into a work structure aperture without forcing so as to preclude any possible injury to the work structure, and which, when fully applied, securely clamps and retains the work structure between its opposite ends.

Still another object of the present invention is to provide a novel unit including a plurality of the devices of the above described type for simplifying handling of the devices and feeding of successive devices to an applying station.

Other objects and advantages of the present invention will become apparent from the following descrip tion wherein:

Fig. 1 is a perspective view showing a fastening device embodying the features of the present invention;

Fig. 2 is an enlarged sectional view showing the device of Fig. 1 partially assembled with a work structure;

Fig. 3 is a perspective view showing the condition of the device of Fig. 1 after the pin has been driven in;

Fig. 4 is an enlarged fragmentary sectional view showing the fastening device fully applied to the work structure;

Figs. 5 and 6 are sectional views of a modified form of the present invention wherein the pin is separate from the tubular plastic member and respectively show the device partially and fully assembled with a work structure;

Figs. 7 and 8 are sectional views respectively showing the device partially and fully assembled with an apertured workpiece and also showing how the device may be used as a bearing for rotatably supporting a shaft;

Figs. 9 and 10 are partial fragmentary sectional views respectively showing the device partially and fully applied to an apertured panel and also showing how the device may be used as an electrical bulkhead connector for electrically insulating a connecting pin from the metal apertured wall or panel;

Fig. 11 is a plan view showing a plurality of the devices initially arranged and molded in a spiral and interconnected so as to provide a unit which may be easily handled and fed to an applying station;

Fig. 12 is an elevational view of the unit shown in Fig. 11; and

Fig. 13 is a simplified view showing how the devices in the unit may be successively fed to an applying station for successive application to an apertured work structure.

Referring now more specifically to the drawings wherein like parts are designated by the same numerals throughout the various figures, a device or fastener 20 embodying one form of the present invention is shown in Figs. 1 through 4. The device 20 is molded or otherwise formed in one piece from resilient plastic material such as nylon or tetrofluorpolyethylene sold under the name of Teflon. it will be appreciated that other suitable plastic materials may also be used.

The device 20 comprises an annular head portion or flange 22 adapted to engage one side of a work structure. A tubular body portion 24 extends axially from the flange for insertion into a work structure aperture. The tubular body portion is formed so that its wall is continuous and uninterrupted and is preferably provided with smooth surfaces and uniform internal and external diameters throughout its length. At the entering end of the tubular body portion 24 a continuous and uninterrupted bead 26 is provided, which bead initially has an outer diameter similar to the outer diameter of the tubular body and an internal diameter substantially less than the internal diameter of the tubular body so that the bead projects radially inwardly as shown in Fig. 2. The head 26 is also preferably provided with a rounded cross section. A pin portion 28 having an external diameter substantially equal to the internal diameter of the tubular body portion is initially integrally connected to the head flange portion 22 at a narrow annular junction 30. A short tapered end portion 32 of the pin projects axially inwardly of the tubular body from the junction 30 and the remaining major portion of the pin 28 initially projects axially outwardly from the flange 22. The outwardly projecting major portion of the pin has an axial length substantially equal to the total of the axial lengths of the head portion 22, the body portion 24 and the bead 26 for the purpose set forth below.

The device 20 is adapted to be applied to any suitable apertured Work structure and in the embodiment shown in Figs. 2 and 4 the device is applied to a pair of workpieces or panel 34 and 36 having aligned apertures 38 and 40 respectively for connecting these workpieces together. The external diameters of the body and bead portions 24 and 26 are substantially equal to and preferably slightly less than the diameters of the apertures 38 and 40 so that the device may be easily slipped into the apertures as shown in Fig. 2. It should be noted that the axial length of the tubular body portion is preferably slightly less than the overall thickness of the work structure provided by the panels 34 and 36. After the device is partially assembled with the work structure as shown in Fig. 2, the pin 28 is driven inwardly so as to rupture the annular connecting section 30 and advance the pin to the position shown in Fig. 4. As the pin moves towards the position shown in Fig. 4 the tapered end portion 32 initially engages the inwardly projecting bead 26 and causes the head to roll outwardly over and into engagement with the outer surface of the workpiece 36. This rolling action which is promoted by the rounded cross section of the bead causes the bead to engage the outer surface of the workpiece 36 in a manner which places the tubular body portion 24 under tension so that the work structure is firmly and securely clamped between the outwardly rolled bead and the head flange 22. This tensioning and clamping action is further promoted by making the length of the body portion 24 slightly less than the thickness of the work structure and also by proportioning the pin 28 so that maximum diameter section of the pin abuts and retains the bead in the outwardly rolled condition when the pin is fully driven into the body portion as shown in Fig.4.

Figs. 5 and 6 show a modified form of the present invention which is similar to the above described embodiment as indicated by the application of identical reference numerals with the sufrlx a added to corresponding elements. This embodiment differs only in that the securing pin 28a is initially formed separate from the plastic fastener device 20a. This embodiment enables the pin to be formed from any suitable material, plastic or otherwise. For example,.in certain installations it may be desirable to form the pin 28a from a relatively hard material or any material having one set of characteristics while the device 20a is formed from resilient plastic material having another set of characteristics.

Figs. 7 and 8 show another embodiment of the present invention which is similar to the structures described above as indicated by the application of identical reference numerals with the suffix b added to corresponding elements. In this embodiment the device 20b is used as a bearing for rotatably mounting a shaft 28b. The shaft 28b thus replaces the securing pins described above and is applied to the device 20b in the same manner as the securing pins for rolling the bead 26b outwardly. After the shaft 28b is assembled as shown in Fig. 8, it is retained against axial movement by a pair of thrust collars 42 and 44 respectively secured thereto by said screws 46 and 48. It should be noted that in this embodiment the flange 2212 provides a thrust bearing for engagement with the collar 44 and the outwardly rolled bead 261) provides a thrust bearing for engagement with the collar 42.

Figs. 9 and show how the device of the present invention may be used as an electrical bulkhead connector assembly. In this embodiment the pin 28c serves as an electrical conductor through the panel or bulkhead 340. After assembly, the pin may be permanently connected to electrical conductors at opposite sides of the bulkhead, or the pin may have opposite end portions 51) and 52 especially formed as shown for accommodating quick disconnect terminals 54 and 56 of electrical conductors 58 and 60 at opposite sides of the bulkhead. In this embodiment the pin is preferably provided with a flange or abutment 62 for engaging the head or flange 22c to limit movement of the pin through the device 20c. In addition the pin is preferably provided with a shallow groove 64 cooperable with the bead 260 for restraining withdrawal of the pin.

Figs. 11, 12 and 13 show a unit 66 including a plurality of integrally connected devices of this invention, which unit may be handled, shipped and the like so as to eliminate individual handling of the devices. In the embodiment illustrated the unit 60 includes a series of the devices 20, but it is to be understood that the above described devices 20a through 200 could also be arranged in similar units. The devices 20 of the unit 66 are formed by molding them in a multiple cavity mold, not shown, wherein the cavities are spirally arranged and connected by passageways so that the flange portions of adjacent devices 20 are integrally connected by small easily severable elements 68. The spiral arrangement of the devices in the unit 66 enables a large number of the devices to be connected in a single series while keeping the size or bulk of the unit at a minimum. Since the devices 20 in the unit 66 are connected in a single continuous series, the unit may be unwound for successively feeding the devices to a work or applying station 70 as shown in Fig. 13 without separating the devices in advance of the work station. Suitable means, not shown, may be provided for feeding the devices succes sively to the work station at which is located means 72 for supporting the work structure and means including a reciprocable punch 74 for applying the devices to the work structure.

While the preferred embodiments of the present inven- 4 tion have been shown and described herein it is obvious that many structural details may be changed without departing from the spirit and scope of the appended claims.

The invention is claimed as follows:

1. A device of the type described for application to an apertured structure having a predetermined thickness comprising a molded resilient plastic member including a circumferentially continuous and integral circular body having a substantially uniform wall thickness throughout its entire length insertable into the apertured structure and having substantially smooth continuous internal and external surfaces each of substantially uniform diameter throughout its length, integral head flange means at one end of said body presenting a radially extending surface for engaging one side of said structure when the device is applied thereto, and a substantially continuous annular bead of rounded cross section integral with the entering end of said body, said head having an initial external diameter substantially the same as the external diameter of the body and an internal diameter substantially less than the internal diameter of said body, said bead being spaced from said radially extending surface of the head flange means a distance slightly less than said predetermined thickness, and an elongated member of circular cross section insertable through said plastic member and including a first section having a major diameter substantially the same as said internal diameter of said body with a length at least substantially as great as the combined lengths of said head flange means, said body, and said head; and said elongated member including a tapering entering end section integrally connected with said first mentioned section and having a predetermined end diameter less than the internal diameter of said head and merging into the major diameter of said first section to present a cam surface for bodily rolling the annular bead radially outwardly to a diameter greater than the external diameter of said body and with its peripheral integrity maintained for engagement with the opposite side of said structure when said elongated member is inserted through said plastic member, to place the body under tension, said elongated member remaining in the body after assembly with a surface of the major diameter portion thereof positioned for engagement with the internal surface of the outwardly rolled bead to prevent resilient return of the bead under influence of the tensioned body away from engagement with the said opposite side of the structure.

2. A device, as defined in claim 1, wherein said elongated member includes a plastic pin integrally connected with said head means by a rupturable section so that the pin may be driven axially through said tubular body into engagement with said annular head.

3. A device, as defined in claim 1, wherein said elougated member is initially separate from said plastic member.

4. A device, as defined in claim 1, wherein said plastic member tubular body provides a bearing rotatably receiving said elongated member, and wherein said head means comprises a radially extending flange providing a thrust hearing at one end of said body, and said annular bead upon being rolled radially outwardly provides a thrust hearing at the opposite end of said body.

References Cited in the file of this patent UNITED STATES PATENTS 583,309 McLaughlin May 25, 1897 1,951,168 Roth Mar. 13, 1934 2,269,895 Foster Jan. 13, 1942 2,358,578 Keehn Sept. 19, 1944 2,402,287 Kearns June 18, 1946 2,596,952 Crowther May 13, 1952 2,657,894 Sklenar Nov. 3, 1953 2,668,468 Flogaus Feb. 9, 1954 2,716,247 Poupitch Aug. 30, 1955 2,830,485 Macy Apr. 15, 1958

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