Mechanical screw transmission
US4198872A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Jul 28, 1978 |
| Grant date | Apr 22, 1980 |
| Priority date | — |
| Expiry date | Jul 28, 1998 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T74/19786
- WIPO fieldMechanical elements
- WIPO sectorMechanical engineering
Abstract
A low-friction light-load mechanical transmission for converting between rotary and linear motion, comprising a screw shaft having a helical thread groove, and a nut body having a radially movable socket member in which there is received a thread-engaging ball. The socket member has a circular load surface surrounding a circumference of the ball, and a second load surface centrally located with respect to the circular load surface and displaced laterally therefrom. The second load surface of the socket member engages the ball along a relatively small area thereof. The helical thread groove is characterized by a pair of co-extensive, helical troughs, each trough being partially circular in cross section. The troughs intersect one another adjacent the root of the thread groove, each trough having a radius of curvature slightly greater than the radius of the ball. The arrangement is such that for a given direction of relative axial movement between the nut body and screw shaft, the ball has a relatively small area of contact with the surface of only one trough, at a point on the ball which is substantially aligned with but opposite to the resultant of the forces existing between the b…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.