US 11,933,386 B2
Anti-backlash mechanism for electromechanical linear actuator
Hung H. Pham, San Jose, CA (US); and Harlan H. Nguyen, San Jose, CA (US)
Assigned to Lin Engineering, Inc., Morgan Hill, CA (US)
Filed by Lin Engineering, Inc., Morgan Hill, CA (US)
Filed on Jul. 13, 2022, as Appl. No. 17/863,391.
Claims priority of provisional application 63/336,160, filed on Apr. 28, 2022.
Prior Publication US 2023/0349452 A1, Nov. 2, 2023
Int. Cl. F16H 25/20 (2006.01); F16H 57/04 (2010.01)
CPC F16H 25/2009 (2013.01) [F16H 57/0464 (2013.01); F16H 57/0497 (2013.01); F16H 2025/2075 (2013.01)] 8 Claims
OG exemplary drawing
 
1. An anti-backlash mechanism for engaging with a leadscrew, comprising:
a main nut having an integral or attached collet with a set of longitudinal slits forming fingers, the collet tapering radially inward toward tips of the fingers at a specified taper angle, the main nut and collet provided with an internal thread for engaging with an external thread of the leadscrew;
an adjustment nut, annular load spring, annular precision shim, and retaining ring sequentially fitting over the collet against the main nut, the adjustment nut, annular load spring and annular precision shim having a degree of longitudinal play between the main nut and retaining ring; and
a pre-load nut with an internal tapered surface that mates with the collet fingers, the internal tapered surface having a specified taper angle that substantially matches that of the collet fingers, the pre-load nut housing the annular load spring and annular precision shim when screwed onto external threads of the adjustment nut by an amount that both compresses the load spring and applies radially inward force to the collet fingers against the leadscrew with an adjustable load dependent upon the amount that the pre-load nut is screwed down upon the adjustment nut.