GB2173564A

GB2173564A - Preventing rotation of bolts on workpieces

Info

Publication number: GB2173564A
Application number: GB08607571A
Authority: GB
Inventors: Ronald Julius Egner; Thomas Charles Alt
Original assignee: Textron Inc; AGAPE Inc
Current assignee: Textron Inc; AGAPE Inc
Priority date: 1985-03-28
Filing date: 1986-03-26
Publication date: 1986-10-15
Also published as: DE3609628A1; GB8607571D0; DE3609628C2; GB2173564B; JPS61228110A; JPH0680324B2

Abstract

A threaded fastener (20c) is non- rotatably mounted for coupling workpieces e.g. for mounting automotive panels or bumpers, and comprises a head (22c) and a shank (26c), and a strip (32c) of a mouldable material, the head (22c) being mouldedly embedded into the strip (32c) towards one end thereof, the head (22c) including first radial projections (36) for resisting rotational movement relative to the strip (32c) and second radial projections (38) for resisting axial movement relative to the strip (32c), the undersurface of the head (22c) being exposed for clamping engagement with a workpiece (12). The free end (64) of the strip (32c) may be secured by a screw or an integral post to the workpieces; alternatively a second similar fastener head may be embedded in the free end (64). <IMAGE>

Description

SPECIFICATION Fastener-carrier system The present invention is directed generally to the fastener arts and more particularly to a novel fastener-carrier system including a carrier strip and one or more fasteners for use in coupling together a pair of workpieces, for example.

The fastener-carrier system of the invention is particularly adapted for use in joining a pair of workpieces at abutting, substantially flat surface portions thereof. Such a fastener-carrier system is particularly useful, for example, in the automotive industry for joining panels to underlying support structures.

More specifically, such a fastener-carrier system may be utilized to affix a bumper to a mounting plate portion of a shock absorbing structure, of the type often utilized in impact-resistant bumper assemblies. In such applications, it should be recognized that a shank portion of the fastener must generally project outwardly of the mounting plate or other first workpiece to interfit with a complementary aperture on the bumper or other second or overlying workpiece. Thereafter, the fastener may be engaged with the second workpiece, in the case where a threaded fastener is used, by engaging a complementary threaded fastener therewith.

It will be recognized that it is difficult and time consuming for the worker or assembler to perform such an assembly with conventional threaded fasteners. The assembler must first locate and insert the fastener through an aperture in the first workpiece, and then hold the fastener in place while starting the complementary fastener on the thread thereof. Thereafter the assembler must hold the first fastener against rotation to assure the desired torque upon the second or mating fastener with respect thereto and the desired degree of gripping of the workpieces therebetween. In this regard, it will be recognized that an intermediate mating fastener cannot be utilized to initially position, and hold the first fastener in place when the two workpieces are to be held in abutting relationship.

The prior art has proposed utilizing studs welded directly to the first or underlying workpiece to solve the foregoing problems. However, this requires that the weld be substantially clean and flush with the surface, thereby requiring additional grinding or smoothing steps, to assure the desired flat and abutting condition of the two workpieces. Moreover, the welded stud has very little corrosion resistance in the area of its couling or welding to the first or underlying workpiece. In automotive assemblies, it will be recognized that these structures are constantly exposed to corrosive environmental conditions. Hence, the prior art system may fail due to corrosion of the critical welded areas of the stud.

Moreover, the weld must withstand a substantial amount of torque applied by the tool which applies the mating fastener or nut to the threaded shank of the stud. The axial force created as the mating fastener seats must also be accommodated by the weld. Failure and/or breakage of the stud relative to its mounting surface either during assembly or afterward due to stresses encountered during assembly is to be avoided.

Accordingly, it is a general object of the invention to provide a novel and improved fastener for joining a pair of workpieces in abutting condition.

A more specific object is to provide a fastenercarrier system in accordance with the foregoing object which substantially avoids the above-noted problems.

A related object is to provide a fastener-carrier system in accordance with the foregoing object which is relatively simple and inexpensive in its design and manufacture and yet highly reliable in operation.

Briefly, and in accordance with the foregoing objects, fastener carrier system in accordance with the invention comprises one or more metallic threaded fasteners, the or each fastener including a head portion and an externally threaded shank portion defining an axis; and a carrier strip comprising a substantially flat, elongate member of a mouldable material; the fastener head portion being mouldably embedded into the carrier strip towards one end thereof, with the threaded shank portion projecting outwardly of the carrier strip; and the fastener head portion including first radially projecting means for resisting rotational movement relative to the carrier strip and second radially projecting means for resisting axial movement relative to the carrier strip with the undersurface of the head portion being exposed for clamping engagement with a workpiece.

The invention also includes a method for forming such a fastener-carrier system comprising the steps of providing a metallic threaded fastener including a head portion and a threaded shank portion projecting from the head portion; forming a substantially flat, elongate carrier strip of a mouldable material; and mouldably embedding the fastener head portion into the carrier strip towards one end thereof, with the shank portion projecting outwardly thereof, during formation of the carrier strip; the fastener head portion being formed with first radially projecting means for resisting rotational movement relative to the carrier strip ar d second radially projecting means for resisting axial movement relative to the carrier strip and the undersurface of the head portion being exposed for clamping engagement with a workpiece.

Additional features of the present invention will be introduced in the following description taken in connection with the accompanying drawings, in which like reference numerals identify like elements, and in which Figure 1 is a side elevation, partially in section, of a fastener-carrier system in accordance with the invention together with a pair of workpieces being joined thereby; Figure 2 is an enlarged side elevation of a fastener member of the system of the invention; Figure 3 is an underneath view of the fastener of Figure 2; Figure 4 is a side elevation, partially broken away, showing the fastener-carrier system of Figure 1; Figure 5 is a view taken generally from the line 55 of Figure 4; Figure 6 is a side elevation, partially in section of a second embodiment of fastener-carrier system in accordance with the invention;; Figurz 7 Is a view taken generally from the line 777 of Figure 6; Figure 8 is a side elevation partially in section, of yet a further embodiment of fastener-carrier system in accordance with the invention; and Figure 9 is a view taken generally from the line 9~9of or Figure 8.

Referring now to the drawings, and initially to Figures 1 to 5, a fastener-carrier system in accordance with the invention is designated generally by the reference numeral 10. In Figure 1, the fastener-carrier system 10 is shown joining a pair of workpieces 12, 14. The workpiece 12 may comprise a mounting plate portion of an automobile bumper assembly and the workpiece 14 may comprise a portion of the automobile bumper. In this regard, both workpieces 12 and 14 are relatively thin and have substantially flat outer surfaces at least in the region where they are to be joined by the fastener-carrier system 10 of the invention. Hence, the fastener-carrier system 10 joins the two workpieces 12, 14 together in substantially flat, surface-to-surface abutting condition.The respective workpieces 12 and 14 are also provided with respective pairs of alignable through apertures 1516, 1#18for receiving portions of the fastener-carrier system or assembly 10 therethrough as will presently be seen.

In accordance with the invention, the fastenercarrier system 10 comprises at least one threaded fastener 20. The fastener 20 preferably comprises a metallic threaded fastener including a head portion 22, a leading tip portion 24, and an externally threaded shank portion 26 intermediate the head 22 and tip 24. This threaded shank portion 26 preferably has a major thread diameter much smaller than the outer diameter of the head portion 22 but larger than the outer diameter or maximum cross-sectional dimension of tip portion 24.

Moreover, the shank 26 defines an axis as generally indicated by phantom line 30 in Figure 2.

The fastener-carrier system 10 also includes a carrier portion comprising a substantially flat, elongate carrier strip or member 32, formed of a mouldable material. In accordance with the invention, the fastener head portion 22 is moulded into or mouldably embedded within the carrier strip 32 towards one end thereof, such that the tip 24 and the threaded shank 26 project outwardly of the carrier strip 32. As best viewed in Figures 4 and 5, the shank 26 extends generally normally to the head 22 and is also generally normal or at right angles to a substantially flat undersurface 34 of the carrier strip 32.

The fastener head portion 22 will be seen to include a first radially projecting means comprising a lobular pattern defined by a plurality of radially extending lobes or undulating surfaces 36 for substantially resisting rotational movement relative to the carrier strip 32 once embedded therein. This pattern 36 defines a driver head-like portion of head 22. In this regard, during the moulding or formation of the carrier strip about the head 22, it will be seen that the material of the carrier strip will tend to flow about these lobes 36 except for the under surfaces thereof which are left exposed so that a metal-tometal clamping engagement can be attained. This forms a relatively secure mechanical interlock between the carrier strip and the head for resisting relative rotation between the fastener and the carrier strip.Moreover, a second radially projecting means, taking the form of a web portion 38 comprising web-like members extending between the lobes 36 is provided as a topmost portion of the fastener head 22 and comprises a relatively thin layer or portion of the material thereof. This web portion 38 is totally embedded and provides means for resisting axial movement, that is, in the direction of the axis 30 of the fastener 20 relative to the carrier strip 32.

It will be recognized that the resistance to both radial and axial movement provided by the foregoing structure of the head 22 is helpful in accommodating forces applied to the fastener 20, for example, when a mating fastener such as an internally threaded fastener or nut 40 is being applied thereto as illustrated in Figure 1. To provide further resistance to rotational movement between the head 22 and the carrier strip 32, an additional recess 42 is formed in an uppermost portion of the head 22. The recess preferably has a generally undulating or lobular surface, which is preferably substantially similar to and centered with respect to the lobes 36 previously described.

For additionally preventing such relative rotation or stripping of the head 22 from carrier strip 32 during application of nut 40, an additional toolreceiving surface or means 44 is formed on the tip 24, which tool-receiving means or surface 44 takes the form of an undulating, radially projecting series of surfaces or lobes of substantially similar but smaller form to the lobes 36 previously described. In this regard, the tool-receiving means or lobes 44 may receive a complementary tool to hold the fastener against rotation during application of the mating internally threaded fastener or nut 40 to the threaded shank portion 26. In this regard, a power tool may be utilized to apply the mating fastener 40 and may impart substantial torsional forces thereto.

Hence, the above-described structure is most advantageous in assuring that such forces, as well as the axial force along shank 26 experienced upon tightening of the fastener 40, will not dislodged the fastener 20 from the carrier strip 32.

Preferably, the lobes or lobular configurations of the radially projecting means 36, the recess 42 and of the tool-receiving portion 44 all comprise a multilobular and preferably hex-lobular configuration of the type shown and described in US-PS 3,584,667.

Moreover, while the web portion 38 extends intermediate each of the lobes 36 of the multilobular driver head portion 36, it will be understood that such a web portion 38 may extend only intermediate selected ones of the lobes 36 without departing from the invention.

In the embodiment illustrated in Figures 1 to 5, a second substantially identical fastener 20a is also mouldably embedded in or moulded into the carrier strip 32 towards an opposite end thereof from the first fastener 20. This second fastener is substantially identical to the fastener 20 already described. Hence, like reference numerals with a suffix a designate like portions of fastener 20a. A threaded shank portion 26a of this second fastener 20a projects outwardly of the carrier strip substantially in parallel with the shank portion 26 of first fastener 20.

In this embodiment of the carrier strip 32 is substantially symmetrically formed, including a pair of generally increased-thickness fastener-receiving region 46,48 to either end thereof. Accordingly, the respective fasteners 20 and 20a are also substantially symmetrically located with respect to the bi-ended, symmetrical carrier strip thus defined.

A middle or intermediate portion 50 of the carrier strip may as seen in Figure 4, be of decreased thickness and may additionally include a further recessed or reduced thickness portion 52 intermediate the increased thickness end or fastener-receiving portions 46 and 48. These portions 46 and 48 may additionally be provided with apertures 54, 56 therein for viewing a topmost surface or portion of the fasteners 20 and 20a therein. In the installation illustrated in Figure 1, tubular or sleeve-like spacers 58, 59 are provided within the apertures 1516 and 18-18 surrounding the shanks 26, 26a.

Referring now to Figures 6 and 7, a second embodiment of fastener-carrier system in accordance with the invention is designated generally by reference numeral lob. The same reference numerals together with suffix b will be used herein to describe portions of the structure of the fastener-carrier system 1 Ob which are identical with the like-numbered portions or structures of the fastener-carrier system 10 of Figure 1. In this regard, the fastener-carriers system 1 Ob includes a similar fastener member or portion 20b comprising shank 26b, tip 24b and head 22b embedded in a first end portion 46b of a carrier strip 32b. The fastener 20b is substantially identical to the fastener 20 of Figures 2 and 3.

However, looking to the opposite end of carrier strip 32b, a projecting post means or portion 60 is formed, projecting outwardly of the substantially flat bottom surface 34b in generally the same direction as the shank 26b of the fastener 20b.

Preferably, this projecting post 60 is of substantially similar length to the shank 26b of the fastener 20b, including the tip portion 24b thereof. Moreover, the projecting post 60 is preferably cylindrical in configuration, having a diameter substantially similar to the maximum thread diameter of the threaded shank 26b. Preferably, an increased thickness end portion 62 of the carrier strip 32b which carries the post 60 is of somewhat lesser lateral extent outwardly of the post 60 than the lateral outward extent of the end portion 46b generally to the left of the fastener shank 26b as viewed in Figure 6.

Referring now to Figures 8 and 9, yet another embodiment of fastener-carrier system in accordance with the invention is designated generally by reference numeral 10c. In similar fashion to the embodiment of Figures 6 and 7, like reference numerals with the suffix c will be used in Figures 8 and 9 to describe substantially identical portions or structures thereof. In this regard, one end 46c of a carrier strip 32c receives a fastener 20c moulded therein. This fastener 20c is also substantially identical to the fastener 20 of Figures 2 and 3.

At the opposite end of the carrier strip 32c a somewhat enlarged thickness portion 64 is formed, substantially similar in length and width to the portion 46c. However, differing from the previous embodiments, this latter carrier strip end portion 64 has formed therein a through aperture 66, preferably having a cross-sectional dimension of the same order as the maximum thread diameter of the fastener threaded shank portion 26c. As best seen in Figure 9, the through aperture 66 is preferably oval in form the iesser cross-sectional dimension of the aperture 66 preferably being substantially similar to the majorthread diameter ofthe threaded shank 26c, while the other or larger cross-sectional dimension thereof is somewhat greater.

Preferably, the mouldable material comprising the carrier strip 32 in each of the embodiments described above comprises a corrosion-resistant plastics material. Moreover, the metal threaded fasteners 20 in each of the above-described embodiments are preferably coated with a corrosion resistant coating material, at least on the portions thereof which project from the carrier strip.

From the foregoing, it will be appreciated that the method of forming a fastener-carrier system of the type described generally involves moulding the head portion of the fastener into the carrier strip towards one end thereof during the formation, as by moulding of the carrier strip itself. This may include moulding into place a pair of similar threaded fasteners 20 and 20a as in the embodiment of Figures 1 to 5. Alternatively, a projecting post such as the post 60 of the embodiment of Figures 6 and 7 or a through aperture such as the aperture 66 of th embodiment of Figures 8 and 9 may be formed in the carrier strip 32c, preferably during formation thereof. However, the aperture 66 may also be formed later by a suitable drilling, punching or other process.

Claims

1. A fastener-carrier system comprising: one or more metallic threaded fasteners, the or each fastener including a head portion and an externally threaded shank portion defining an axis; and a carrier strip comprising a substantially flat, elongate member of a mouldable material; the fastener head portion being mouldably embedded into the carrier strip towards one end thereof, with the threaded shank portion projecting outwardly of the carrier strip; and the fastener head portion including first radially projecting means for resisting rotational movement relative to the carrier strip and second radially projecting means for resisting axial movement relative to the carrier strip with the undersurface of the head portion being exposed for clamping engagement with a workpiece.

2. A fastener-carrier system according to Claim 1, wherein the shank includes a tip portion defining a tool receiving means of predetermined configuration for receiving a complementary tool to hold thafastener against rotation during application or removal of a mating internally threaded fastener to the threaded shank portion.

3. A fastener-carrier system according to Claim 1 or Claim 2 wherein the first radially projecting means defines a multi-lobular portion having a plurality of lobes of predetermined configuration.

4. A fastener-carrier system according to any one of Claims 1 to 3 wherein the second radially projecting means defines web-like members intermediate at least selected ones of the first radially projecting means.

5. A fastener-carrier system according to Claim 2, wherein the predetermined configuration of the tool-receiving means comprises a hex-lobular configuration.

6. A fastener-carrier system according to Claim 3, wherein the predetermined configuration of the driver head lobes comprises a hex-lobular configuration.

7. A fastener-carrier #system according to any one of Claims 1 to 6, wherein a second, substantially identical fastener is mouldably embedded in the carrier strip towards an opposite end thereof and has a threaded shank portion projecting outwardly of the carrier strip substantially in parallel with the first fastener shank portion.

8. A fastener-carrier system according to any one of Claims 1 to 6, wherein a projecting post member is formed integrally with the carrier strip towards an opposite end thereof and projects therefrom in the same direction as the fastener shank portion.

9. A fastener-carrier system according to any one of Claims 1 to 6, wherein a through aperture is formed in the carrier strip towards an opposite end thereof from the fastener.

10. A fastener-carrier system according to any one of Claims 1 to 9, wherein the nioudable material comprising the elongate member is a corrosion resistant plastic material.

11. A fastener-carrier system according to any one of Claims 1 to 10, wherein a corrosion resistant coating is applied to at least the portions of the metallic threaded fastener which project from the carrier strip.

12. A method of forming a fastener-carrier system comprising the steps of providing a metallic threaded fastener including a head portion and a threaded shank portion projecting from the head portion; forming a substantially flat, elongate carrier strip of mouldable material; and mouldably embedding the fastener head portion into the carrier strip towards one end there#of, with the shank portion projecting outwardly thereof, during formation of the carrier strip; the fastener head portion being formed with first radially projecting means for resisting rotational movement relative to the carrier strip and second radially projecting means for resisting axial movement relative to the carrier strip and the undersurfaces of the head portion being exposed for clamping engagement with a workpiece

13. A fastener-carrier system substantially as hereinbefore described with reference to Figures 1 to 5, or 6 and 7, or 8 and 9 of the accompanying drawings.

14. A method of forming a fastener-carrier system substantially as hereinbefore described with reference to Figures 1 to 5, or 6 and 7, or 8 and 9 of the accompanying drawings.