Item 0344
DESIGN: SynchroLite ~ Power Train - Clutch -
Overrunning - Ratchet Layout
Overview:
To give exact rotational location between masts (rotor disks) and engines, A device for exactly locating the rotational position of the ring gear must be used in conjunction with this.
This unit is designed to have an OD and width that is interchangeable with: Power Train - Clutch - Overrunning Roller - 295 lb-ft, Model ASK60
0567
Drawing:
Use 3 dogs. This will result in 1/ less loading on each dog and 2/ better centralizing of clutch on mast.
Number of Dogs:
|
Ratio |
Nbr of Ratchets That Can Be Used * |
Degrees Between Maximum Nbr. of Ratchets |
|
1:1 |
1 |
360 |
|
2:1 |
1 or 2 |
180 |
|
3:1 |
1 or 3 |
120 |
|
4;1 |
1 or 2 or 4 |
90 |
|
5:1 |
1 or 5 |
72 |
|
6:1 |
1 or 3 or 6 |
60 |
|
7:1 |
1 or 7 |
51.4286 |
|
8:1 |
1 or 2 or 4 or 8 |
45 |
|
9:1 |
1 or 3 or 9 |
40 |
|
9.8:1 ** |
1 |
360 |
|
10:1 |
1 or 2 or 5 |
36 |
|
11:1 |
1 or 11 |
32.7273 |
|
12:1 |
1 or 2 or 3 or 4 0r 6 or 12 |
30 |
*
The number of dogs may be increased by a multiple of 2 or 3 etc. but the number of 'tracks' must be increased by the same multiple.**
If the ratio is not an integer than there can only be 1 dog, per 'track'.Note: I have not (yet) been able to find a primary [Eagle Pd] and secondary [Planetary] ratio that will give an exact 10:1 ratio; where 5 dogs can be used in the same track.
Size of Pawl:
Operating tooth pressure should be kept in the neighborhood of 1000 to 1500 psi.
[Source ~ MDD p.56] Operating tooth pressure should be 2500 psi for steel subject to shock, 4000 psi when not subjected to shock. [Source ~ MH p.2004] The maximum torque, of one drive, at the mast is 262 ft-lb. The radius at the center of the dog is 1.5134" therefore the pressure is 262 * (12 / 1.5134) = 2077 lbs. This means that each of the 3 dogs must have approximately 0.33 sq-in of area.Activation Speed:
The engagement speed will be around 280 RPM (4.66 RPS). This is not very fast for throwing the spring-loaded dogs out so make the diameter as large as possible.
Spline ~or~ Keyways:
For spline see:
MAKE: Power Train - Mast - MachiningFor a number of shallow keyways see:
[not done yet]
Articles:
Roach, G.M., 1998,"An Investigation of Compliant Over-Running Ratchet and Pawl Clutches," M.S. Thesis, Brigham Young University, Provo, Utah.
Roach, G.M., Lyon, S.M., and Howell, L.L., 1998, "A Compliant, Over-Running Ratchet and Pawl Clutch with Centrifugal Throw-Out," Proceedings of the 1998 ASME Design Engineering Technical Conferences, DETC98/MECH-5819.
Patents that might be relevant:
http://www.ibiblio.org/patbin/gettit1?CLSC=192-53H
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Last Revised: August 14, 2001