US2916949A

US2916949A - Differential timing device mechanism

Info

Publication number: US2916949A
Application number: US682057A
Authority: US
Inventors: Edwin R Smith; Constantine F Cafolla
Original assignee: Seneca Falls Machine Co
Current assignee: Seneca Falls Machine Co
Priority date: 1957-09-04
Filing date: 1957-09-04
Publication date: 1959-12-15
Anticipated expiration: 1976-12-15

Description

United States Patent.

DIFFERENTIAL TllVIING DEVICE MECHANISM Edwin R. Smith, Seneca Falls, and Constantine F. Cafolla, Waterloo, N.Y., assignors to Seneca Falls Machine Chempany, Seneca Falls, N.Y., a corporation of Massac usetts Application September 4, 1957, Serial No. 682,057

1 Claim. (Cl. 74-689) such feeding operations or other machine functions may be controlled.

It is the general object of this invention to provide improved mechanism by which the angular movement of the timing drum will be at all times coordinated with the linear movement of the tool carriage, when either singly or jointly operated and controlled.

To the attainment of these objects, we utilize a differential connection between the drum and the primary and the secondary means for feeding the moving member or tool carriage.

The single figure of the drawing is a diagrammatic plan view, partly in section, of the driving mechanism adapted to the stated purposes of this invention.

Referring to the accompanying drawing, a tool carriage 10 rotatably supports a gear nut 11 threaded on a lead screw 12. The screw 12 is normally held stationary by a magnetic friction brake 14. The gear nut 11 is revolved by a meshing gear 15, also rotatably supported on the carriage 10. The gear 15 is slidable on a rotated splined shaft 16. Rotation of the gear 15 by the shaft 16 rotates the gear nut 11 on the stationary lead screw 12, and causes the nut 11 to be moved axially of the lead screw and to move the tool carriage 10 along with it.

The shaft 16 may rotate the lead screw 12 through sprockets 20 and 21 and a chain 22. The sprocket 20 is driven from the shaft 16 through a magnetic clutch 23. When the clutch 23 is activated, the screw 12 will be rotated by the shaft 16, and the gear nut 11 thus receives an additional axial movement, providing a differential in crease in the rate of tool carriage travel. Suitable control means determines that when the clutch 23 is to be closed, the brake 14 will be automatically released.

The shaft 16 will be normally and continuously rotated by a gear 27 from any suitable source of power.

A control or timing drum 30 is to be turned angularly in either direction in predetermined relation to the rotation of the feed shaft 16 and lead screw 12.

The drum 30 has a Worm gear 31 continuously rotated by a worm 32 on a worm shaft 33. The shaft 33 is mounted in

bearings

35 and 36 and has an offset arm 37 on which a planet pinion 38 is freely rotatable.

A sun gear 49 is mounted on a drive shaft 41 which is rotatably mounted for timed rotation by the splined shaft 16 through sprockets 42 and 43 and a chain 44.

The planet pinion 38 also meshes with internal gear teeth 59 on a differential casing 51, which in turn is loosely mounted on the drive shatt 41. The casing 51 is driven by

sprockets

54 and 55 and a chain 56 from the lead screw 12.

As has been previously explained, the normal linear movement of the tool carriage 10 is effected by turning the gear nut 11 on the normally fixed lead screw 12. Such rotation of the gear nut 11 is also communicated to the sun gear 40 through the sprockets 42 and 43 and chain 44. i

The differential casing 51 is normally held from rotation by the brake 14, and the sun gear 40 rotates the arm 37 and worm 32 to turn the worm gear 31 and timing drum 30 at a proportional but much reduced speed.

For faster carriage travel, the lead screw 12 is itself rotated by closing the magnetic clutch 23 and by simultaneously opening the magnetic clutch 14, thus imparting an additional and bodily axial movement to the nut 11 and carriage 10. Such rotation of the lead screw 12 also acts through the

sprockets

54 and 55 and chain 56 to rotate the casing 51 and to thus superpose additional rotational speed on the drum 30 to correspond to the increased tool carriage travel.

The rotation of the drum 30 is thus at all times coordinated with the travel of the carriage Ill, and this proportional relation between linear travel and angular displacement is maintained unchanged by changes in either the speed or the direction of carriage travel.

Contact pins 60in one or more series may be selectively mounted in the drum 30 and may activate any usual limit switches to effect desired changes in speed or direction of carriage travel, or other machine functions.

It is to be understood that the magnetic brake 14 will be released whenever the magnetic clutch 23 is activated, and vice-versa.

Any suitable provision may be made for selective control. of the brakes and switches in accordance with tool carriage travel. One such arrangement is shown in the patent to Dinsmore and Smith #2,714,324 issued August 2, 1955.

Having thus described our invention and the advantages thereof, we do not wish to be limited to the details herein disclosed, otherwise than as set forth in the claim, but what we claim is:

In a machine tool having a tool carriage, in combination, a normally-stationary and axially-fixed lead screw, a gear nut mounted on said carriage and having its nut portion threaded on said lead screw, normally-operated means to rotate said nut 'on said normally-fixed lead screw to shift said tool carriage bodily axially of said normallyfixed lead screw in said machine tool, a drum rotated in predetermined relation to the axial movement of said tool carriage, and driving means for said drum comprising a three-part differential gear means having an outer but internally-toothed driven gear, an inner but externallytoothed driving gear, and an interposed gear mounted on a bearing portion of a crank arm and connecting said gears, an operating connection from one part of said differential gear means to said lead screw, and an operating connection from a second part of said differential gear means to the means for rotating the gear nut, whereby rotation of the control drum is made responsive to any and all axial movements of said tool carriage.

References Cited in the file of this patent UNITED STATES PATENTS 1,283,386 Wenzelmann on. 29,1918 2,144,735 Granberg et a1. Jan. 24, 1939 2,359,255 Smith Sept. 26, 1944 OTHER REFERENCES Ser. No. 309,100, Robin et al. (A.P.C.), published May 4, 1943.