Dual-action disposable clamp

• US 20080213063A1
• Filed: 10/05/2007
• Published: 09/04/2008
• Est. Priority Date: 10/05/2006
• Status: Active Grant

• Current Assignee: John D. Pratt
• Original Assignee: Monogram Aerospace Fasteners, Inc. (TriMas Corporation)
• Inventors: Pratt, John D.
• Granted Patent: US 8,511,952 B2
• Time in Patent Office: Days
• US Class Current: 411/43
• CPC Class Codes: F16B 13/066 fastened by extracting a separate expander-part, actuated by the screw, nail or the like
• CPC Class Codes: F16B 31/021 by means of a frangible part F16B31/025, F16B31/028 take precedence; break members in torque limiters or torque indicators in wrenches or screwdrivers B25B23/1415
• CPC Class Codes: Y10T 29/49826 Assembling or joining

Abstract

A clamp and a method for installing the clamp into at least two work pieces is provided. The clamp has a shank keyed to an expander. The expander engages the core bolt such that rotation of the core bolt bulbs the expander to clamp the work pieces. A spacer engages the shank to prevent rotation of the shank during installation. The shank has a flange fracturing at a predetermined compression load. The core bolt optionally has a first and a second break groove fracturing at predetermined compression loads. A nut is optionally provided to engage the spacer.

Claims

1. A blind clamp capable of insertion through aligned apertures of a plurality of work pieces, said clamp comprising;

a core bolt having a length defined between a first end and a second end;

an expander threadingly engaged with the core bolt at the first end of the core bolt; and

a shank positioned between the expander and the second end of the core bolt, the shank having an integral flange adapted to separate from the shank at a predetermined compression load, the integral flange having a diameter greater than the shank.

2. The clamp of claim 1 wherein the shank is keyed to the expander such that preventing the shank from rotation prevents the expander from rotation.

3. The clamp of claim 1 wherein the expander bulbs as the core bolt is threaded into the expander.

7. The clamp of claim 1 further comprising:

a spacer adjacent the integral flange of the shank, the shank extending through the spacer and keyed to the spacer.

8. The clamp of claim 7 wherein fracturing the second break groove separates the core bolt from the spacer.

9. The clamp of claim 8 wherein the core bolt, the shank and the expander extract from the work pieces together upon fracturing the second break groove.

10. The clamp of claim 7 wherein the spacer has a wrenchable outer surface.

11. The clamp of claim 7 wherein the shank has a protuberance extending from the shank and engage the spacer to rotationally key the shank and spacer together.

12. The clamp of claim 7 wherein the spacer has an outer diameter substantially similar to the diameter of the flange of the shank.

4. The clamp of claim I wherein the core bolt has a first break groove that is sized to fracture at a predetermined amount of torque.

5. The clamp of claim 4 wherein the core bolt has a second break groove that is sized to fracture at a different amount of torque than the first break groove.

6. The clamp of claim 5 wherein the first break groove fractures at a lower amount of torque applied to the core bolt than the second break groove.

13. A clamp capable of insertion through aligned apertures of two or more work pieces, said clamp comprising:

a core bolt;

an expander in threaded engagement with said core bolt, the expander capable of expanding to a diameter larger than said core bolt; and

a nut in threaded engagement with the core bolt, the core bolt extending through the nut, wherein rotation of the core bolt in a first direction rotates the nut in the same direction and wherein rotation of the core bolt in a second direction opposite the first direction unthreads the core bolt from the nut.

14. The clamp of claim 13 wherein the core bolt has at least one wrenchable surface on one end and external threads extending from said wrenchable surface to the opposite end thereof.

15. The clamp of claim 14 further comprising:

a spacer adjacent the nut, the spacer having a bore wherein the core bolt extends through the bore of the spacer.

16. The clamp of claim 15 further comprising:

a shank positioned between the spacer and the expander, the shank rotationally keyed to the spacer and the expander.

17. The clamp of claim 14 wherein the shank has a flange portion adjacent the spacer, the flange portion fracturing at a predetermined compression load.

18. The clamp of claim 14 wherein the spacer having a bore sized to receive the shank there through, said bore preventing rotation of the shank during rotation of the core bolt while said spacer is rotationally restrained.

20. The method of claim 18 wherein the core bolt has a first break groove.

23. The method of claim 20 further comprising the step of:

removing the core bolt from the work pieces by further rotating the core bolt to fracture the core bolt at the second break groove.

19. A method of clamping at least two work pieces together, the method comprising the steps of:

inserting a clamp into the work pieces, the clamp comprising;

a core bolt having a first break groove;

an expander in threaded engagement with the core bolt;

a shank positioned between the expander and the wrenching end of the core bolt, the shank keyed to the expander such that the shank is capable of preventing the expander from rotating, the shank having an integral flange; and

a spacer having a wrenching outer surface and a bore formed therein, the shank having a protuberance engaging the bore of the spacer, the spacer capable of preventing rotation of the shank and the expander;

placing the integral flange of the shank into contact with at least one of the work pieces;

preventing rotation of the spacer;

rotating the core bolt into the expander to bulb the expander; and

fracturing the flange at a predetermined compression load, such that said shank is movable into said spacer and the expander clamps the work pieces against the spacer.

21. The method of claim 19 further comprising the step of:

rotating the core bolt to fracture the core bolt at the first break groove to terminate the clamping of the work pieces to one another.

22. The method of claim 19 wherein the core bolt has a second break groove adapted to fracture at an applied torque that is greater than the torque required to clamp the work pieces to one another.

24. The method of claims 19 further comprising the step of:

unthreading the core bolt from said expander; and

removing the clamp from the work pieces.