Self-adjusting fastener assembly

A fastener having resilient means interconnecting a head portion and a threaded portion for maintaining tight axial fitment between mating parts and compression on a gasket therebetween whereby to assure a leak free mating. A method of forming the fastener is also disclosed.

What is claimed is:

1. A fastener comprising a head portion, a threaded portion, a coil spring having opposite end sections, each end section being rigidly and nonrotatably secured, respectively, to said one and said other portions, and a resilient body of elastomeric material encapsulating said coil spring.

2. A fastener comprising a head portion, a threaded portion, a coil spring having opposite end sections, each end section being rigidly secured, respectively, to said one and said other portions, a resilient body of elastomeric material encapsulating said coil spring, and a rigid sleeve encircling said body of elastomeric material to resist radial deformation of said body during longitudinal threading engagement of the fastener, the opposite ends of said sleeve being disposed adjacent one respective end of said coil spring.

3. The fastener as recited in claim 2 wherein the head portion includes an annular flange, and said elastomeric body includes an outwardly extending annular portion sandwiched between said flange and one end of said sleeve.

4. A fastener comprising a head portion, a threaded portion, a coil spring having opposite end sections, each end section being rigidly and nonrotatably secured, respectively, to said one and said other portions, and a resilient body of elastomeric material encapsulating said coil spring, said spring being helically wound with individual coils at each end section thereof defining a cylindrical inner surface sized to fit about and fixedly engage the outer periphery of its respective one of said portions.

5. A fastener comprising a head portion, a threaded portion, a coil spring having opposite end sections, each end section being rigidly secured, respectively, to said one and said other portions, and a resilient body of elastomeric material encapsulating said coil spring, said spring being coiled in an opposite hand as that of the thread on said threaded portion.

6. A fastener comprising a pair of axial shanks, one shank including a partially threaded portion extending therefrom and further comprising resilient torque means including a body of elastomeric material for transmitting torque from one shank to the other shank, said torque means interconnecting said shank portions and resisting relative axial movement therebetween.

7. The fastener as recited in claim 6 wherein said resilient torque means comprises a tension spring connected at one end to one of said shanks and at the opposite end to the other of said shanks, said spring being adapted to axially extend upon fastening engagement of said threaded portion.

8. The fastener as recited in claim 7 wherein said spring is encapsulated in said body of elastomeric material.

9. A fastener comprising a pair of axial shanks, one shank including a partially threaded portion extending therefrom and further comprising resilient torque means including a body of elastomeric material for transmitting torque from one shank to the other shank, said torque means interconnecting said shank portions and resisting relative axial movement therebetween, said torque means comprising a tension spring connected at one end to one of said shanks and at the opposite end to the other of said shanks, said spring being a helically coiled spring having a center axis, the inner surfaces of said coils at each end of the spring being sized to receive and be nonrotatably secured to one respective shank disposed therein with the coil axis being aligned with said shanks, said spring being adapted to axially extend upon fastening engagement of said threaded portion.

10. The fastener as recited in claim 9 wherein a continuous body of elastomer is disposed around and between adjacent coils to resist otherwise uninhibited axial expansion or contraction of said spring.

11. A fastener comprising: a pair of axial shanks, one shank including a partially threaded portion extending therefrom; resilient torque means including a body of elastomeric material for transmitting torque from one shank to the other shank, said torque means interconnecting said shank portions and resisting relative axial movement therebetween; and a sleeve encircling said resilient torque means for transmitting axial fastening force and maintaining the lateral exterior configuration of said resilient torque means.

12. A fastener comprising a pair of axial shanks, one shank including a partially threaded portion extending therefrom; resilient torque means including a body of elastomeric material for transmitting torque from the other shank to said one shank, said torque means interconnecting said shank portions and resisting relative axial movement therebetween; resilient torque means comprising a tension spring connected at one end to one of said shanks and at the opposite and to the other of said shanks, said spring being adapted to axially extend upon fastening engagement of said threaded portion, said spring is encapsulated in said body of elastomeric material and a rigid sleeve grippingly engaging the outer periphery of said body whereby to prevent radial distortion of said resilient torque means.

13. The fastener as recited in claim 11 wherein the other of said shanks includes an annular shoulder, said sleeve is generally cylindrically shaped and includes an annular end face, and said body includes an annular flange of elastomeric material extending radially therefrom and sandwiched axially between and engaging said shoulder and end face.

14. The fastener as recited in claim 9 wherein said coils have a helical pitch of opposite hand to that of said threaded portion.

15. A fastener comprising a pair of axially spaced, axially aligned, unthreaded axial shanks, one shank including a head and the other shank including a body having a threaded portion, and an axially extensible, substantially radially confined, torque transmitting coil spring extending between and nonrotatably connected at its opposite axial ends to a respective shank, whereby torque applied to the head is transmitted through the spring and to the body resulting in the threaded portion being driven.

16. A fastener comprising: a pair of axially spaced, axially aligned, unthreaded axial shanks, one shank including a head and the other shank including a body having a threaded portion; an axially extensible, substantially radially confined, torque transmitting coil spring extending between and nonrotatably connected at its opposite axial ends to a respective shank, whereby torque applied to the head is transmitted through the spring and to the body resulting in the threaded portion being driven; and a cylindrical body encompassing the spring and its connections to the shanks.

17. The fastener as recited in claim 16 wherein said cylindrical body comprises elastomer which completely encapsulates said spring.

18. A fastener comprising a pair of axially spaced, axially aligned, unthreaded axial shanks, one shank including a head and the other shank including a body having a threaded portion, and an axially extensive, substantially radially confined, torque transmitting coil spring extending between and nonrotatably connected at its opposite axial ends to a respective shank, whereby torque applied to the head is transmitted through the spring and to the body resulting in the threaded portion being driven, said torque transmitting spring being a helically wound coil with the interior surfaces of the end coil portions thereof being disposed about and secured to the respective shanks.

19. The fastener as recited in claim 15 wherein the coil spring is a tension spring which is axially extended and if extensed further is overstressed and permanently axially extended to assume a new length.

20. The fastener as recited in claim 15 wherein the coils are of opposite hand to that of said threaded portion.

21. A fastener comprising: a pair of axially spaced, axially aligned, unthreaded axial shanks, one shank including a head and the other shank including a body having a threaded portion; an axially extensible, substantially radially confined, torque transmitting coil spring extending between and nonrotatably connected at its opposite axial ends to a respective shank, whereby torque applied to the head is transmitted through the spring and to the body resulting in the threaded portion being driven; and a rigid cylindrical sleeve encompassing the spring and its connections to the shanks, said cylindrical sleeve comprising an elastomer which completely encapsulates said spring, said sleeve being disposed in gripping relation about the body of elastomer whereby to inhibit radial distension of the elastomer when torque is applied to the fastener.