Threaded Fastener with Retainer and Method of Making Such Fastener
A fastener element (16) has a head section (18), a threaded shank section (17) with threads (20) at a pitch and a distal end section (22). A retention device (24) is secured to the distal end section and is engageable with a fastener receiving member (14).
The field of this invention relates to a threaded fastener with a retainer at its distal end and a method of manufacturing the threaded fastener.
BACKGROUND OF THE DISCLOSUREThreaded fasteners have long been used to join two or more components. It has been found advantageous to easily prelocate a threaded fastener and mate parts prior to torque tightening the fastener into location by rotating along a thread helix. This is particularly true with assemblies where the orientation and weight of the mating parts require that the parts be held in place while a driving tool is retrieved and placed in location to engage the fastener for tightening the fastener in place.
Previous snap in fasteners have been overly complicated and added unacceptable costs to fasteners when used in high volume during an assembly line operation.
What is needed is a low cost expeditiously manufactured threaded fastener with a retainer that can be pushed into position with a low entry force and be able to resist a much higher exiting or pulling force to temporarily hold two mating parts together.
SUMMARY OF THE DISCLOSUREIn accordance with one aspect of the invention, a fastener assembly has a fastener member with a head section constructed to be engageable with a driving tool. A threaded shank section has threads at a pitch. A retention device member is secured to a distal end section integrally formed with the fastener member. The retention device is engageable to a fastener receiving member, for example a nut, when the distal end section is inserted into a hole therethrough.
Preferably the distal end section of the threaded fastener member has a circumferential groove. The retention device engages the circumferential groove to be positively engaged onto the distal end section by being adheredly molded. In one embodiment, the distal end section is in the form of a dog point.
The threaded shank section is self-threading for engaging the hole in the fastener receiving member. The hole is initially unthreaded. It is desirable that the retention device has at least one outer extension flange section angled radially outwardly and axially toward the head section and is sized to engage an inside wall of the hole in the fastener receiving member to provide insertion of the fastener assembly in the hole with a low entry force and to resist higher exiting forces.
In one embodiment, the retention device is a cap member that is molded over the distal end section. The cap member has at least one outer extending flexible flange extending radially outwardly and axially toward the head section. At least one outer extending flange has a pitch corresponding to the pitch of threads on the threaded shank section. The hole in the fastener member can be initially threaded. The distal end section can be axially inserted into the hole with a low entry force and resist greater axial exiting forces and be threaded out of the hole. The flange can snap fit over the threads in the hole when the fastening member is axially pushed in.
According to another aspect of the invention, a fastener assembly has a fastener element with a self-threading shank section, an engageable head section and a distal dog point. The distal dog point has an undercut section spaced from an end. A retention device member is in the form of an elastomeric cap molded over the distal dog point with a rim section inwardly extending to engage and adhere to the undercut section. The cap has at least one outer flange sized to engage an internal wall of a hole in a fastener receiving member. At least one outer flange is angled radially outwardly and axially toward the head section.
In accordance with another aspect of the invention, a reusable fastener assembly includes a fastener element having a threaded shank section with threads at a pitch, a head section, and a distal end section. The distal end section has an undercut section spaced from an end. A retention device member is engaged to the undercut section with at least one radially extending flange sized to engage internal threads in a hole of a fastener receiving member. At least one flange is tapered radially outwardly and axially toward the head section and is flexible in one direction to snap fit into the internal threads with an axial directed entry force onto the fastener assembly but resist a higher axial exiting force. At least one flange has a pitch corresponding with the pitch of the threads on the threaded shank section and with the internal threads of the hole such that the retention device member can be threaded out of the hole for reuse with the fastener element.
In accordance with another aspect of the invention, a method of manufacturing a fastener assembly includes the steps of roll forming a headed blank to form a threaded fastener member with threads on a shank portion and a distal end with a retaining shaped end, placing the threaded fastener member in a mold, and adheredly molding a retention device on the distal end with the retaining shaped end.
Preferably, the roll forming forms a retaining groove in the distal end, and the adheredly molding includes molding the retention device to extend into the retaining groove.
In accordance with another aspect of the invention, a method of manufacturing a threaded fastener includes placing a headed blank between two roll dies each having a threaded roll section and a contour section with an apex laterally extending beyond the threaded roll section and positioned at the bottom end of the threaded roll section and roll forming the headed blank to simultaneously form threads and a distal end with a retainer groove on a shank portion thereof.
In accordance with another aspect of the invention, a roll die for manufacturing a fastener has a threaded roll section for rolling threads into a headed blank, and a contour section at the bottom of the thread roll section with an apex downstream from an open beginning to roll form a groove in the headed blank below a formed threaded section. Preferably, the contour has its apex near a mid-point of the roll die.
Reference now is made to the accompanying drawings in which:
Referring now to
Referring now to
The retainer cap member 24 also has an outwardly extending flange 32 that has a taper radially outward and toward the head section 18. Flange 32 can extend 360 degrees completely about the cap member outer diameter. The flange 32 also has a diameter sized larger then the unthreaded hole 34 in the weld nut 14. As shown in
Referring to
Referring now to
As shown in
The fastener member 217 with the retainer cap may be rotated to either fasten the threads into the nut 214 or can be rotated in an opposite rotational direction to remove both the fastener member 217 and the retainer cap 224 from the nut 214 such that the fastener assembly 216 may be reused.
The reusable fastener element shown in
All of the above embodiments provide temporary retention with the nut without the need of the fastener assembly protruding beyond the nut. This aspect is advantageous when there is little or no space or clearance behind the nut. However it is foreseen that many applications may provide for a clearance or extra space behind the nut. In these applications a retainer device 324 may have its outer flange 332 as shown in
For all the above described embodiments, a fastener can be temporarily located in either a threaded or unthreaded nut hole holding two members temporarily in place. While these fastener assemblies are particularly suitable to be dimensioned for resisting up to 5 lb. of exiting force without disengaging the nut for retaining the airbag anchor in place, the fastener assemblies may be sized up or down for other applications, including applications with exiting forces exceeding 5 lbs. The fastener can be quickly pushed into place while an operator may then retrieve an appropriate driving tool to then rotate each fastener member along its thread helix to its final tightened condition with the nut. The use of these fastener assemblies provides for a so called third hand for the operator and can speed up an assembly line type operation.
For lighter duty applications, the overmold feature of the rim 30 into a groove 26 may be eliminated and the fastener member may be retained solely by frictional engagement between the cap member molded onto the fastener member.
Referring now to
Once the fastener is expeditiously formed using the roll dies, the fastener member 17 is placed in a mold 60 as shown in
Referring now to
Other variations and modifications are possible without departing from the scope and spirit of the present invention as defined by the appended claims.
Claims
1. (canceled)
2. (canceled)
3. (canceled)
4. (canceled)
5. (canceled)
6. (canceled)
7. (canceled)
8. (canceled)
9. (canceled)
10. (canceled)
11. A reusable fastener assembly comprising:
- a fastener element having a threaded shank section with threads at a pitch, a head section, and a distal end section;
- said distal end section having an undercut section spaced from an end;
- a retention device member engaged to said undercut section with at least one radially extending flange sized to engage internal threads in a hole of a fastener receiving member; said at least one flange being tapered radially outwardly and axially toward said head section and being flexible in one direction to snap fit into said internal threads with an axial directed entry force onto said fastener assembly but resist greater axially directed exiting forces; and
- said at least one flange having a pitch corresponding with the pitch of the threads on said threaded shank section and with said internal threads of said hole such that said retention device member can be threaded out of said hole for reuse with said fastener element.
12. A method of manufacturing a fastener assembly comprising the steps of:
- roll forming a headed blank to form a threaded fastener member with threads on a shank portion and a distal end with a retaining shaped end;
- placing said threaded fastener member in a mold; and
- adheredly molding a retention device on said distal end with said retaining shaped end.
13. A method as defined in claim 12 further comprising:
- said roll forming forms a retaining groove in said distal end; and
- said adheredly molding includes molding said retention device in said retaining groove.
14. A method as defined in claim 12 wherein said threads and said retainer shaped end are formed simultaneously by said roll forming.
15. (canceled)
16. A roll die for manufacturing a fastener comprising:
- a threaded roll section for rolling threads into a headed blank; and
- a contour section at the bottom of the thread roll section with an apex downstream from an open beginning to roll form a groove in said headed blank below a formed threaded section.
17. A roll die as defined in claim 16 further comprising:
- said contour having its apex near a mid-point of said roll die.
Type: Application
Filed: Jul 11, 2007
Publication Date: Nov 26, 2009
Inventors: Michael G. Dietz (Oxford, MI), Richard S. Brown (Brantford), Charles Earl Abbate (Clinton Township, MI), Chris Fenech (Brownstown, MI)
Application Number: 12/373,128
International Classification: F16B 25/00 (20060101); B21H 3/04 (20060101); B21J 13/02 (20060101);