US 4,593,572 AGranted

Lubricated drive mechanism

AssigneeUniversal Thread Grinding Company

InventorFrancis M. Linley, Jr.

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Abstract

A sealed, precision screw feed device for equipment of the type having a stationary base and a reciprocating carriage member. The device has an elongate tubular housing carrying a shaft with a precision thread, one end of the shaft projecting from one end of the housing and being adapted for connection to a suitable drive motor carried on the base. A nut is disposed completely within the housing, carried by the shaft and connected with a hollow thrust rod that projects from the opposite end of the housing. The housing contains a quantity of lubricant; shaft seals at its opposite ends prevent the lubricant from leaking out past the threaded shaft and thrust rod. The exposed end of the thrust rod has a universal joint which is connected to the carriage member. Also, the bore of the thrust rod is sealed off, to prevent lubricant from escaping through this avenue. The disclosed arrangements provide precision movement of the carriage member, even over extended periods of use. The operation is characterized by minimal wear of the various parts, and significantly reduced operating temperatures, especially at the more frequent points of contact of the nut and shaft. Lubricant can be temperature-controlled at an external point and pumped through the housing to further minimize wear.

Claims19

Dependent claims

A sealed screw feed device comprising, in combination:

(a) an elongate tubular housing having an interior containing a continuous uniform diametered bore and openings at both its ends communicating with said bore,
(b) a bearing for a shaft, disposed in the housing adjacent one of its ends,
(c) a shaft having precision threads, said shaft being disposed within said housing and having a drive portion journaled in said bearing and projecting from said one end of the housing, and said drive portion being provided with means for engagement by a drive device to effect its turning,
(d) a nut carried in the housing by said shaft and engaging the precision threads, said nut undergoing axial movement with respect to the housing and shaft as the shaft turns,
(e) a hollow thrust rod at one end attached to said nut, said thrust rod projecting from the other end of said housing and receiving portions of said shaft,
(f) seals disposed in the ends of the housing, engaging the drive portion of said shaft and the hollow thrust rod respectively, to seal the interior of the housing against loss of lubricant,
(g) said thrust rod having a transverse interior wall intermediate its ends to prevent the passage of lubricant through it from the housing,
(h) universal hinge means carried by an exterior portion of the thrust rod, and
(i) means connected with said universal hinge means, for attaching the same to a reciprocatable member of a peice of equipment for effecting reciprocation of the member as the shaft is turned first in one direction and then in an opposite direction,
(j) all portions of said nut and all portions of the thurst rod that project into the housing being smaller than the housing bore to provide clearance which constitutes a substantially continuous and uninterrupted annular flow space therebetween past which lubricant can be forced as the nut traverses the shaft, thereby to minimize the drag of any piston effect which the nut might have on the lubricant.

7 more elements

A traverse mechanism, comprising in combination:

(a) a base having track means thereon,
(b) a carriage movable with respect to the base, having track means engaged with said track means of the base,
(c) a tubular housing carried by the base,
(d) a screw shaft having an axis of rotation and having a drive portion projecting from one end of said housing,
(e) said shaft having a threaded portion disposed substantially completely within the housing,
(f) a nut disposed substantially completely within the housing and engaging the threaded portion of the screw shaft,
(g) a thrust rod connected with the nut and extending from the other end of the housing, said rod being connected to said carriage to drive the same along said track means of the base,
(h) said base having a surface comprising a pair of generally planar intersecting faces, disposed at an angle with respect to one another,
(i) said housing having an exterior surface comprising a pair of generally planar intersecting faces, disposed at an angle same as that of said base faces with respect to one another and respectively disposed flat against the faces of the base surface,
(j) said planar intersecting faces of the housing surface lying in planes which provide for accurate alignment of the axis of the screw shaft with respect to the path of the carriage along the track means of the base,
(k) said carriage longitudinally surrounding a substantial portion of said housing.

8 more elements

Dependencies are inferred from the claim text.