1. An exercise apparatus comprising:
a frame;
a pivoting member with a proximate end pivotally connected to the frame and a free distal end;
an elastic member having one end fastened to the pivoting member proximate to the distal end of the pivoting member; and
an anchor device fastening a second end of the elastic member to the frame, the anchor device comprising:
an elongated support member having a central axial portion, an upper mounting portion, and a lower mounting portion, the mounting portions being fastened to the frame; and
a first plurality of curved arms extending outward from the central axial portion wherein each curved arm has a distal end sized to receive and retain the second end of the elastic member.
2. The exercise apparatus of claim 1 wherein the distal end of each curved arm extends substantially parallel to the central axial portion.
3. The exercise apparatus of claim 1 wherein the distal end of each curved arm includes a feature shaped to prevent the second end of the elastic member from slipping off the curved arm.
4. The exercise apparatus of claim 1 further comprising a cradle fastened to said pivot arm between the distal and proximal ends for supporting the elastic member when the elastic member is not fastened between the distal end of the pivot member and the anchor device.
5. The exercise apparatus of claim 1 wherein the first plurality of curved arms extend outward from a first side of the elongated member and the first plurality of curved arms defines a first plane passing through the central axial portion.
6. The exercise apparatus of claim 5 wherein a second plurality of curved arms extend outward from a second side of the elongated member in the plane passing through the central axial portion.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1. A method of making a rotor blade comprising:
providing a preform including an airfoil stub and a dovetail hub;
first electrochemical discharge machining said hub using a first rotary electrode disk to form a rough dovetail;
electrochemical machining said stub to form an airfoil;
second electrochemical discharge machining said rough dovetail using a second rotary electrode disk to form a rough tang; and
finish machining said rough tang to form a dovetail extending from said airfoil in a unitary rotor blade.
2. A method according to claim 1 wherein:
said first disk includes a perimeter profile with a center ridge bounded on opposite sides by smaller diameter lands; and
said second disk includes a perimeter profile having a center groove bounded on opposite sides by a larger diameter lands.
3. A method according to claim 2 further comprising:
passing said first disk along a first side of said hub to cut a first groove therein;
passing said first disk along an opposite second side of said hub to cut a second groove; and
passing said second disk along the bottom of said rough dovetail to cut away both said first and second grooves to form said rough tang.
4. A method according to claim 3 further comprising:
circulating an electrolytic coolant between said hub and disks;
electrically powering said hub and disks to effect electrical sparks therebetween to electrically erode material from said hub;
translating together a pair of electrode plates on opposite sides of said stub;
circulating an electrolyte between said stub and plates; and
electrically powering said stub and plates to electrochemically remove material from said stub to form said airfoil while avoiding sparking.
5. A method according to claim 4 further comprising:
fixturing said stub in an ECDM machine atop a supporting table adjacent to an arbor supporting said disks; and
rotating said arbor and disks, and translating said table and preform to cut said grooves in said hub to form said rough dovetail.
6. A method according to claim 5 wherein:
said preform is fixtured laterally from said stub atop said table to expose a side of said hub to said first disk for cutting said groove therein; and
said preform is fixtured vertically from said airfoil atop said table to expose the bottom of said rough dovetail to said second disk for forming said rough tang therefrom.
7. A method according to claim 6 wherein:
said rough dovetail includes said first and second grooves on opposite sides thereof forming a reference datum; and
said rough dovetail is fixtured at said grooves during said ECDM to form said airfoil relative to said reference datum.
8. A method according to claim 7 wherein said airfoil is fixtured during said second ECDM to form said rough tang relative thereto.
9. A method according to claim 8 wherein said finish machining said rough tang comprises precision grinding thereof to remove recast and heat affected zones therefrom due to said ECDM.
10. A method according to claim 9 wherein:
said first and second ECDM are performed using a single ECDM machine for both operations; and
said ECM is performed using an ECM machine located near said ECDM machine in a common cell controlled by a single operator.
11. A method of making a rotor blade comprising:
providing a preform including an airfoil stub and a dovetail hub;
first electrochemical discharge machining said hub to form a rough dovetail;
electrochemical machining said stub to form an airfoil;
second electrochemical discharge machining said rough dovetail to form a rough tang; and
finish machining said rough tang to form a dovetail extending from said airfoil in a unitary rotor blade.
12. A method according to claim 11 wherein:
said first and second ECDM include different electrode disks rotating along said hub to electrically erode material therefrom to form said rough dovetail and said tang in turn; and
said ECM includes a pair of electrode plates translating together on opposite sides of said stub to electrochemically remove material from said stub to form said airfoil.
13. A method according to claim 12 further comprising:
circulating an electrolytic coolant between said hub and disks;
electrically powering said hub and disks to generate electrical sparks therebetween to electrically erode material from said hub;
circulating an electrolyte between said stub and plates; and
electrically powering said stub and plates to electrochemically remove material from said stub while avoiding sparking.
14. A method according to claim 13 further comprising:
fixturing said stub in an ECDM machine atop a supporting table adjacent to an arbor supporting said disks; and
rotating said arbor and disks, and translating said table and preform to cut a groove in said hub to form said rough dovetail.
15. A method according to claim 14 wherein said preform is fixtured laterally from said stub atop said table to expose a side of said hub to one of said rotating disks for cutting said groove therein.
16. A method according to claim 15 wherein said one disk includes a perimeter profile with a center ridge bounded on opposite sides by small diameter lands.
17. A method according to claim 14 wherein said preform is fixtured vertically from said airfoil atop said table to expose the bottom of said rough dovetail to one of said rotating disks for forming said rough tang therefrom.
18. A method according to claim 17 wherein said one disk includes a perimeter profile having a center groove bounded on opposite sides by larger diameter lands.
19. A method according to claim 13 further comprising:
passing a first one of said rotating electrode disks along a first side of said hub to cut a first groove therein; and
passing said first rotating disk along an opposite second side of said hub to cut a second groove therein.
20. A method according to claim 19 wherein said first disk includes a perimeter profile with a center ridge bounded on opposite sides by small diameter lands.
21. A method according to claim 19 further comprising passing a second one of said rotating electrode disks along the bottom of said rough dovetail to cut away both said first and second grooves and form said rough tang.
22. A method according to claim 21 wherein said second disk includes a perimeter profile having a center groove bounded on opposite sides by larger diameter lands.
23. A method according to claim 13 wherein:
said rough dovetail includes first and second grooves on opposite sides thereof forming a reference datum; and
said rough dovetail is fixtured at said grooves during said ECDM to form said airfoil relative to said reference datum.
24. A method according to claim 23 wherein said airfoil is fixtured during said second ECDM to form said rough tang relative thereto.
25. A method according to claim 24 wherein said airfoil is fixtured during said second ECDM without encapsulation thereof.
26. A method according to claim 13 wherein said finish machining said rough tang comprises precision grinding thereof to remove recast and heat affected zones therefrom due to said ECDM.
27. A method according to claim 13 wherein:
said first and second ECDM are performed using a single ECDM machine for both operations; and
said ECM is performed using an ECM machine located near said ECDM machine in a common cell controlled by a single operator.
28. A method according to claim 27 wherein said single ECDM machine includes a common rotary arbor supporting a first one of said electrode disks for performing said ECDM, and a second one of said electrode disks for separately performing said second ECDM.
29. A method according to claim 28 wherein said ECDM machine further includes a common table having separately mounted thereon one of said preforms fixtured laterally from said stub thereof atop said table to expose a side of said hub to said first disk, and another one of said preforms fixtured vertically from said airfoil thereof to expose the bottom of said rough dovetail to said second disk.
30. A method according to claim 29 wherein:
said first disk is configured for cutting grooves in opposite sides of said hub in sequential passes, and under oscillation to form said rough dovetail; and
said second disk is configured to simultaneously cut away said grooves to form said rough tang.
31. A method of making a product comprising:
providing a preform including a stub and a hub;
first electrochemical discharge machining said hub to form a first shape;
subsequent to the first electrochemical discharge machining, electrochemical machining said stub to form a first part;
subsequent to the electrochemical machining, second electrochemical discharge machining said first shape to form a second shape; and
finish machining said second shape to form a second part extending from said first part in a unitary product.
32. A method according to claim 31 wherein:
said first and second ECDM include different electrode disks rotating along said hub to electrically erode material therefrom to form said first shape and said second shape in tum; and
said ECM includes a pair of electrode plates translating together on opposite sides of said stub to electrochemically remove material from said stub to form said first part.
33. A method according to claim 32 further comprising:
circulating an electrolytic coolant between said hub and disks;
electrically powering said hub and disks to generate electrical sparks therebetween to electrically erode material from said hub;
circulating an electrolyte between said stub and plates; and
electrically powering said stub and plates to electrochemically remove material from said stub while avoiding sparking.
34. A method according to claim 33 further comprising:
fixturing said stub in an ECDM machine atop a supporting table adjacent to an arbor supporting said disks; and
rotating said arbor and disks, and translating said table and preform to cut a groove in said hub to form said first shape.
35. A method according to claim 34 wherein said preform is fixtured vertically from said first part atop said table to expose the bottom of said first shape to one of said rotating disks for forming said second shape therefrom.
36. A method according to claim 33 further comprising:
passing a first one of said rotating electrode disks along a first side of said hub to cut a first groove therein; and
passing said first rotating disk along an opposite second side of said hub to cut a second groove therein.
37. A method according to claim 33 further comprising passing a second one of said rotating electrode disks along the bottom of said first shape to cut away both said first and second grooves and form said second shape.
38. A method according to claim 33 wherein:
said first shape includes first and second grooves on opposite sides thereof forming a reference datum; and
said first shape is fixtured at said grooves during said ECDM to form said first part relative to said reference datum.
39. A method according to claim 33 wherein said finish machining said second shape comprises precision grinding thereof to remove recast and heat affected zones therefrom due to said ECDM.
40. A method according to claim 33 wherein:
said first and second ECDM are performed using a single ECDM machine for both operations; and
said ECM is performed using an ECM machine located near said ECDM machine in a common cell controlled by a single operator.
41. A method according to claim 40 wherein said single ECDM machine includes a common rotary arbor supporting a first one of said electrode disks for performing said ECDM, and a second one of said electrode disks for separately performing said second ECDM.
42. A method according to claim 41 wherein said ECDM machine further includes a common table having separately mounted thereon one of said preforms fixtured laterally from said stub thereof atop said table to expose a side of said hub to said first disk, and another one of said preforms fixtured vertically from said first part thereof to expose the bottom of said first shape to said second disk.
43. A method according to claim 33 wherein said product is a turbine rotor blade, said first part thereof is an airfoil, and said second part thereof is a dovetail.