Claims
- 1. A variably amplified load indicating fastener comprising:
a fastener; a load indicator comprising:
a plate; a needle pivotally supported by the plate; and a first reference mark; a member detachably securing the load indicator to the fastener; a sleeve fitting over the outer circumference of both the load indicator and the member; and the sleeve carrying a second reference mark.
- 2. The variably amplified load indicating fastener of claim 1 wherein:
the plate is a linearly adjustable dial plate.
- 3. The variably amplified load indicating fastener of claim 1 further wherein:
the member has an outer cylindrical surface; the load indicator has an upper cylindrical part; a first fastener fastens the sleeve to the upper cylindrical part; and a second fastener fastens the sleeve to the outer cylindrical surface.
- 4. The variably amplified load indicating fastener of claim 1 wherein the fastener comprises:
a forged-metal bolt having a head and a shank; and a blind bore extending from a top of the head, through the head and partially through the shank.
- 5. The variably amplified load indicating fastener of claim 4 wherein:
the bolt is made from steel, and the head is hexagonal.
- 6. The variably amplified load indicating fastener of claim 1 further comprising:
the fastener having an axis; a blind bore of predetermined diameter and depth, wherein
the blind bore is situated co-axial and internal to the fastener.
- 7. The variably amplified load indicating fastener of claim 6 further comprising:
a clearance gauge pin situated in the blind bore and contacting the load indicator.
- 8. The variably amplified load indicating fastener of claim 6 wherein:
at least a part of the load indicator is located in the blind bore.
- 9. The variably amplified load indicating fastener according to claim 8:said member comprises a main body having a bottom end and an upper recess, and said load indicator further comprises; a spring wire having first and second legs and a closed end joining said legs, said closed end adapted to contact an abutment in said blind bore; a spring wire support member to which said first leg of said spring wire is secured, with said support member secured to the bottom end of said main body with a driving end of said second leg of said spring wire extending into said recess; a compensating plate, having a compensating slot, disposed in said upper recess with said driving end received in and extending through said compensating slot; a spacer plate disposed atop said compensating plate; the indicator dial disposed atop said spacer plate; the indicator needle having a driving slot pivotally mounted to the underside of a dial plate with said driving end received in and extending through said driving slot, said compensating plate, said spacer plate and said dial plate secured to the main body; and a lens press fit into said upper recess of said main body.
- 10. The variably amplified load indicating fastener according to claim 10 wherein:
said compensating slot is a cammed slot which converts wire linear motion to needle rotary motion and gives the indicator needle a linear travel when converting the wire linear motion to needle rotary motion.
- 11. The variably amplified load indicating fastener of claim 1 further comprising:
a blind bore with an enlarged recessed opening at an end thereof; the member is located in the enlarged recessed opening.
- 12. The variably amplified load indicating fastener of claim 1 wherein:
the load indicator has the same coefficient of thermal expansion as the fastener.
- 13. The variably amplified load indicating fastener of claim 1 wherein:
the fastener has an abutment which is moved by a change in length under an applied load; the load indicator further comprises;
a compensating slot; a driving slot; an elongated U-shaped element disposed in the direction in which the load is applied when the fastener is in use, wherein
a first side of the U is rigidly attached to the fastener, a closed end of the U is proximate to and movable by the abutment, and
a second side of the U extends through the compensating slot and the driving slot; the needle is operatively coupled to an outer end of said second side; and a dial.
- 14. The variably amplified load indicating fastener of claim 13 further comprising:
a clearance gauge pin situated between the abutment and the load indicator and contacting the closed end of the U.
- 15. The variably amplified load indicating fastener according to claim 13 wherein:
the abutment is formed by an end of a blind bore internal to and coaxial with the fastener.
- 16. The variably amplified load indicating fastener according to claim 13 wherein:
the sides of the U are resiliently movable relative to each other about the closed end of the U in response to a movement of the abutment.
- 17. The variably amplified load indicating fastener according to claim 13 wherein:
the U is made of wire.
- 18. An amplified load indicating fastener comprising:
a body having an abutment which is moved by changing a length of the body under an applied load, an element, coupled to said abutment, having an outer portion which moves linearly in response to a movement of the abutment, an indicator needle adjustably supported for rotation with respect to said body and coupled to said outer portion to convert linear motion of said outer portion to amplified rotary motion, and an indicator dial juxtaposed with said indicator needle to display an indication of the load applied to the fastener.
- 19. A load indicator comprising:
a main body having a bottom end and an upper recess; a spring wire having first and second legs and a closed end joining said legs body; a driving end of said second leg of said spring wire extending into said recess; a spring wire support member to which said first leg of said spring wire is secured; said support member secured to the bottom end of said main body; a compensating plate, having a compensating slot, disposed in said upper recess; said driving end received in and extending through said compensating slot; a spacer plate disposed atop said compensating plate; a dial plate disposed atop said spacer plate; an indicator needle having a driving slot pivotally mounted to the underside of a dial plate; said driving end received in and extending through said driving slot and operatively coupled to said needle; said compensating plate, said spacer plate and said dial plate secured to the main body; and a lens press fit into said upper recess of said main body.
- 20. The load indicator according to claim 19 wherein:
said compensating slot is a cammed slot which converts wire linear motion to needle rotary motion and is programmed to give the needle indicator a linear travel when converting the wire linear motion to needle rotary motion.
- 21. A method of variably amplifying the load indication of a load indicating fastener which has an indicator which moves linearly in response to the changing length of the body under an applied load comprising converting said linear motion to amplified rotary motion.
- 22. A method of installing a pre-calibrated variable amplification load indicator assembly into a fastener bolt comprising:
threading the pre-calibrated load indicator into a threaded bore of a base member of a fastener until an indicator needle indicates zero on a dial plate; placing a reference sleeve over a main body of the indicator assembly and said base member in a rest position atop the head of the fastener; rotating the reference sleeve until a sleeve reference mark is aligned with a main body reference mark indicating the reference position for zero load on the load indicator dial; locking the reference sleeve in this position; and locking the load indicator in its referenced position.
- 23. A method according to claim 22 and further including removing a load indicator from a load bearing fastener comprising:
unlocking the reference sleeve; unscrewing the load indicator from the base member; and removing the load indicator from the reference sleeve.
- 24. The method according to claim 23 and further including re-installing the load indicator into a load bearing fastener bolt comprising:
inserting. said load indicator through the reference sleeve; threadingly securing said main body into said base member until the indicator needle begins to show movement towards zero on the dial plate; continuing to threadingly securing said main body into said base member until said main body reference mark is aligned with said sleeve reference mark; locking said main body in position.
- 25. A method of calibrating a variable amplification load indicator comprising:
threadingly inserting said load indicator into a base member of a fastener with a spring wire and a pivot point received in a bore of the fastener to contact a gauge pin and then cause a drive end of said spring wire drive end to deflect and rotate a needle until the needle indicates zero on the dial plate; applying a known load to the fastener bolt; observing an amount of travel by the needle; reducing the needle travel by lowering the dial plate if the needle indicates more than 6% greater than the known load being applied to the fastener; increasing the needle travel by raising the dial plate if the needle indicates more than 6% less than the known load being applied to the fastener; and ending the process when the needle indicates within ±6% of the known load being applied to the fastener.
PRIORITY
[0001] The present application claims priority to provisional application No. 60/191,217 filed on Mar. 22, 2000.
PCT Information
Filing Document |
Filing Date |
Country |
Kind |
PCT/US01/09056 |
3/22/2001 |
WO |
|