Carriage drive mechanism

Claim 2

A drive mechanism comprising a frame, a rotating cam means carried by the frame, a carriage movable along the cam means in a cycle of operation, said cam means having an annular groove at one end thereof for idle operation of the carriage, a first helical groove connected with the annular groove and running along the cam means for advancing the carriage in one direction, and a second helical groove of lesser depth connected with the first helical groove and running along the cam means for returning the carriage in the opposite direction, follower means engageable with the cam means for positive driving of the carriage from an idle position through an advance and return cycle of operation, means for moving the follower means from an idle position in the annular groove into the first helical groove for driving the carriage in the advance portion of the cycle, and means for reversing the dirEction of drive of the carriage whereby the follower means is moved from the first helical groove to the second helical groove to be guided at the lesser depth for driving the carriage in the return portion of the cycle back to the idle position.

Claim 3

The drive mechanism of claim 1 wherein said cam means includes a start portion groove connecting the annular groove with the first helical groove, and said moving means effects transfer of the follower means from said annular groove to said start portion groove.

Claim 4

The drive mechanism of claim 1 wherein said reversing means is a reverse portion groove for camming the follower means from the first helical groove to the second helical groove.

Claim 5

The drive mechanism of claim 1 wherein the second helical groove is of greater pitch than the first helical groove.

Claim 6

The drive mechanism of claim 1 wherein said first helical groove is of a depth greater than that of said annular groove, said moving means effects transfer of the follower means from said annular groove to said first helical groove, said second helical groove is connected with said annular groove, and said second helical groove is of a depth approximately that of said annular groove.

Claim 7

In printing apparatus, the combination of a platen, a printer carriage movable along the platen, and means for driving the carriage to and fro in an advance and return cycle of operation, said driving means comprising a rotating cam member supported from the apparatus, a drive pin carried by the carriage and engageable with the cam member throughout the cycle of operation, said cam member having an annular groove at one end thereof and an endless helical groove of a predetermined depth running along the cam member in one direction from said annular groove and of lesser depth running along the cam member in the other direction to said annular groove, means for moving the drive pin at the start of a cycle of operation from the annular groove into the endless groove of predetermined depth for advancing the carriage in said one direction, and means for moving the drive pin from the groove of predetermined depth into the groove of lesser depth for returning the carriage in said other direction and positioning the drive pin for return to the annular groove at the end of the cycle of operation.

Claim 8

In printing apparatus, the combination of a platen, a printer carriage movable along the platen, and means for driving the carriage to and fro in an advance and return cycle of operation, said driving means comprising a rotating cam member supported from the apparatus, a drive pin carried by the carriage and engageable with the cam member throughout the cycle of operation, said cam member having an annular groove at one end thereof and an endless helical groove of a predetermined depth running along the cam member in one direction from said annular groove and of lesser depth running along the cam member in the other direction to said annular groove, means for moving the drive pin at the start of a cycle of operation from the annular groove into the endless groove of predetermined depth for advancing the carriage in said one direction, and means for moving the drive pin from the groove of predetermined depth into the groove of lesser depth for returning the carriage in said other direction and positioning the drive pin for return to the annular groove at the end of the cycle of operation.

Claim 9

The combination of claim 6 wherein the cam member includes a variable pitch groove connecting the annular groove with the groove of a predetermined depth.

Claim 10

The combination of claim 6 wherein the cam member includes a variable-pitch reverse groove for camming the drive pin from the predetermined depth groove into the groove of lesser depth.

Claim 11

A drive mechanism for a high-speed printer having a frame, a platen rotatably supported from the frame, a carriage movable along the platen in a cycle consisting of printing and return portions of operation, and printing mechanism carried by the carriage and capable of imprinting on the platen during at least the printing portion of the cycle, said drive mechanism comprising a continuously rotating cam member supported from the frame and having a deep helical groove extending along the cam member in one direction and a shallow helical groove extending in the opposite direction, an annular groove at one end of the cam member for idle operation of the carriage and a variable-pitch groove connecting the annular groove with the deep helical groove, a drive element guidable in the annular groove during idle operation of the carriage and engageable with the helical grooves throughout the cycle of operation, means for moving the drive element from the annular groove along the variable-pitch groove and into the deep helical groove for driving the carriage in advancing manner during the printing portion of the cycle, and means for moving the drive element from the deep helical groove into the shallow helical groove for driving the carriage in reverse manner during the return portion of the cycle, the drive element being positioned upon return of the Carriage at a groove depth compatible with that of the annular groove.

Claim 12

A drive mechanism for a high-speed printer having a frame, a platen rotatably supported from the frame, a carriage movable along the platen in a cycle consisting of printing and return portions of operation, and printing mechanism carried by the carriage and capable of imprinting on the platen during at least the printing portion of the cycle, said drive mechanism comprising a continuously rotating cam member supported from the frame and having a deep helical groove extending along the cam member in one direction and a shallow helical groove extending in the opposite direction, an annular groove at one end of the cam member for idle operation of the carriage and a variable-pitch groove connecting the annular groove with the deep helical groove, a drive element guidable in the annular groove during idle operation of the carriage and engageable with the helical grooves throughout the cycle of operation, means for moving the drive element from the annular groove along the variable-pitch groove and into the deep helical groove for driving the carriage in advancing manner during the printing portion of the cycle, and means for moving the drive element from the deep helical groove into the shallow helical groove for driving the carriage in reverse manner during the return portion of the cycle, the drive element being positioned upon return of the Carriage at a groove depth compatible with that of the annular groove.

Claim 13

THe drive mechanism of claim 9 wherein the means for moving the drive element from the deep helical groove into the shallow helical groove includes a variable-pitch reverse groove for automatic transferring of the drive pin from one to the other groove.

Claim 14

The drive mechanism of claim 9 wherein the shallow helical groove is of greater pitch than the deep helical groove for fast return of the carriage.