Print guide mechanism

Claim 2

A print guide mechanism comprising: a rotary print element; a right-angle drive for imparting rotation to said rotary print element for the selection of a character to be printed by a type section of said element; a carriage for carrying said rotary print element in a direction transverse to a medium receiving the printing by said print element; a shaft having longitudinal groove means extending transversely of said printing medium, said right-angle drive comprising a gear slidably disposed about said shaft for rotation therewith, said mechanism further comprising key means connecting said gear with said groove means for inhibiting backlash between said gear and said shaft; said key means comprising linear bearing means for permitting translation of said key means along said shaft, rotationally locking said gear to said shaft; said linear bearing means of said key means including screws angled relative to a diameter of said shaft for directing ball bearings to said linear bearing into contact with edges of said groove means; means for rotating said shaft to a designated position for selection of a character to be printed, said rotation means being disposed at a stationary site distant from said movable carriage; worm means for translating said carriage along said shaft, said worm means including a pair of beveled rollers carried by said carriage for mating with inclined surfaces of a worm of said worm means for inhibiting backlash between said worm means and said carriage; and means for rotating a worm gear of said worm means to advance said carriage to a desired position for printing a character on said printing medium, and wherein said rotating means is located at a stationary site distant from said carriage.

Claim 3

A print guide mechanism according to claim 1, wherein said groove means comprise a pair of V-shaped grooves diametrically positioned on said shaft.

Claim 4

A print guid mechanism according to claim 2, wherein said linear bearing means of said key means include a pair of ball races and two pairs of diametrically disposed screws, each pair of screws being angled relative to a diameter of said shaft for directing ball bearings of respective races into contact with opposite edges of respective V-shaped grooves.

Claim 5

A print guide mechanism according to claim 1, wherein said screws are angled for directing ball bearings against opposite edges of said groove means to produce clockwise and counter-clockwise torques which inhibit said backlash.

Claim 6

A print guide mechanism according to claim 1, wherein said right angle drive compises two beveled gears, the first of which is said gear slidably disposed about said first mentioned shaft, the second beveled gear being disposed on a driven shaft extending to said rotary print element, said second gear having central bore through which said driven shaft extends and spring means are provided for urging said second gear into contact with said first gear.

Claim 7

A print guide mechanism according to claim 5 wherein said first gear is made of a harder material than said second gear.

Claim 8

A print guide mechanism according to claim 1, further comprising a tractor means for positioning a medium for receiving printing; said tractor means having a clutch, a manually operable knob and a motor, said knob and said motor being alternately connectable by said clutch to a tread of said tractor means in response to a translatory movement of said knob for alternatively driving said tread by said motor or by said knob.

Claim 9

A print guide mechanism according to claim 7, wherein said worm means further comprises a set of rollers positioned by said carriage against successive turns in a helix of said worm for providing, in conjunction with said pair of beveled rollers, a three-point support for said worm gear to isolate the portion of said worm gear adjacent said carriage from vibrations induced by rotation of said worm gear.

Claim 10

A print guide mechanism according to claim 1, wherein said worm means further comprises a set of rollers positioned by said carriage against successive turns in a helix of said worm for providing, in conjunction with said pair of beveled rollers, a three-point support for said worm gear to isolate the portion of said worm gear adjacent said carriage from vibrations induced by rotation of said worm gear.

Claim 11

A print guide mechanism according to claim 1, wherein said worm means further comprises a set of rollers positioned by said carriage against successive turns in a helix of said worm for providing, in conjunction with said pair of beveled rollers, a three-point support for said worm gear to isolate the portion of said worm gear adjacent said carriage from vibrations induced by rotation of said worm gear.

Claim 12

A print guide mechanism according to claim 1 wherein rail means, extending parallel to said shaft and to said worm means, are provided for further supporting said carriage; and roller means are provided between said carriage and said rail means for rolling said carriage along said rail means.

Claim 13

A print guide mechanism according to claim 11, wherein said rail means comprises a rail on either side of the longitudinal extension of said worm, said roller means comprising at least one pair of rollers contacting each said rail at substantially 90° relative to one another about the axis of a respective rail.

Claim 14

A print guide mechanism according to claim 1, further comprising a frame securing said print element to said right-angle drive, said frame being rotatable about said shaft for pivoting said print element away from said medium to permit interchanging of elements of said print element.

Claim 15

A print guide mechanism comprising: a rotary print element; a right-angle drive for imparting rotation to said rotary print element for the selection of a character to be printed by a type section of said element; a carriage for carrying said rotary print element in a direction transverse to a medium receiving the printing by said print element; a shaft having longitudinally groove means extending transversely of said printing medium, said right angle drive comprising a gear slidably disposed about said shaft for rotation therewith, said mechanism further comprising key means connecting said gear with said groove means for inhibiting backlash between said gear and said shaft; means for rotating said shaft to a designated position for selection of a character to be printed, said rotation means being disposed at a stationary site distant from said movable carriage; worm means for translating said carriage along said shaft, said worm means including a pair of beveled rollers carried by said carriage for mating with inclined surfaces of a worm of said worm means for inhibiting backlash between said worm means and said carriage; means for rotating a worm gear of said worm means to advance said carriage to a desired position for printing a character on said printing medium, and wherein said rotating means is located at a stationary site distant from said carriage; a frame securing said print element to said right angle drive, said frame being rotatable about said shaft for pivoting said print element away from said medium to permit interchanging of elements of said print element; and a tractor means for positioning a medium for receiving printing; said tractor means having a clutch, a manually operable knob and a motor, said knob and said motor being alternately connectable by said clutch to a tread of said tractor means in response to a translatory movement of said knob for alternatively driving said tread by said motor or by said knob.

Claim 16

A print guide mechanism comprising: a rotary print element; a right-angle drive for imparting rotation to said rotary print element for the selection of a character to be printed by a type section of said element; a carriage for carrying said rotary print element in a direction transverse to a medium receiving the printing by said print element; a shaft having longitudinally groove means extending transversely of said printing medium, said right angle drive comprising a gear slidably disposed about said shaft for rotation therewith, said mechanism further comprising key means connecting said gear with said groove means for inhibiting backlash between said gear and said shaft; means for rotating said shaft to a designated position for selection of a character to be printed, said rotation means being disposed at a stationary site distant from said movable carriage; worm means for translating said carriage along said shaft, said worm means including a pair of beveled rollers carried by said carriage for mating with inclined surfaces of a worm of said worm means for inhibiting backlash between said worm means and said carriage; means for rotating a worm gear of said worm means to advance said carriage to a desired position for printing a character on said printing medium, and wherein said rotating means is located at a stationary site distant from said carriage; a frame securing said print element to said right angle drive, said frame being rotatable about said shaft for pivoting said print element away from said medium to permit interchanging of elements of said print element; and a tractor means for positioning a medium for receiving printing; said tractor means having a clutch, a manually operable knob and a motor, said knob and said motor being alternately connectable by said clutch to a tread of said tractor means in response to a translatory movement of said knob for alternatively driving said tread by said motor or by said knob.

Claim 17

A print guide mechanism according to claim 14, wherein said worm means further comprises a set of rollers positioned by said carriage against successive turns in a helix of said worm for providing, in conjunction with said pair of beveled rollers, a three-point support for said worm gear to isolate the portion of said worm gear adjacent said carriage from vibrations induced by rotation of said worm gear.

Claim 18

A print guide mechanism comprising: a rotary print element; a right-angle drive for imparting rotation to said rotary print element for the selection of a character to be printed by a type section of said element; a carriage for carrying said rotary print element in a direction transverse to a medium receiving the printing by said print element; a shaft having longitudinal groove means extending transversely of said printing medium, said right-angle drive comprising a gear slidably disposed about said shaft for rotation therewith, said mechanism further comprising key means for inhibiting backlash between said gear and said shaft; said key means comprising linear bearing means for permitting translation of said key means along said shaft, rotationally locking said gear to said shaft; said linear bearing means of said key means including means angled relative to a diameter of said shaft for directing ball bearings of said linear bearing into contact with edges of said groove means; means for rotating said shaft to a designated position for selection of a character to be printed, said rotation means being disposed at a stationary site distant from said movable carriage; and means for translating said carriage transversely of said printing medium.

Claim 19

A print guide mechanism comprising: a rotary print element; a right-angle drive for imparting rotation to said rotary print element for the selection of a character to be printed by a type section of said element; a carriage for carrying said rotary print element in a direction transverse to a medium receiving the printing by said print element; a shaft having longitudinal groove means extending transversely of said printing medium, said right-angle drive comprising a gear slidably disposed about said shaft for rotation therewith, said mechanism further comprising key means for inhibiting backlash between said gear and said shaft; said key means comprising linear bearing means for permitting translation of said key means along said shaft, rotationally locking said gear to said shaft; said linear bearing means of said key means including means angled relative to a diameter of said shaft for directing ball bearings of said linear bearing into contact with edges of said groove means; means for rotating said shaft to a designated position for selection of a character to be printed, said rotation means being disposed at a stationary site distant from said movable carriage; and means for translating said carriage transversely of said printing medium.

Claim 20

A print guide mechanism according to claim 16, wherein said carriage translating means includes a rotatable member and means located at a stationary site distant from said carriage for rotating said rotatable member to impart translation to said carriage.

Claim 21

A print guide mechanism according to claim 16, wherein said ball bearing directing means are screws, angled for directing ball bearings against opposite edges of said groove means to produce clockwise and counter-clockwise torques which inhibit said backlash.

Claim 22

A print guide mechanism according to claim 18, wherein said groove means comprise a pair of V-shaped grooves diametrically positioned on said shaft.

Claim 23

A print guide mechanism according to claim 19, wherein said linear bearing means of said key means include a pair of ball races and two pairs of diametrically disposed screws, each pair of screws being angled relative to a diameter of said shaft for directing ball bearings of respective races into contact with opposite edges of respective V-shaped grooves.

Claim 24

A print guide mechanism according to claim 16, further comprising a frame securing said print element to said right-angle drive, said frame being rotatable about said shaft for pivoting said print element away from said medium to permit interchanging of elements of said print element.

Claim 25

A print guide mechanism according to claim 21, further comprising a tractor means for positioning a medium for receiving printing; said tractor means having a clutch, a manually operable knob and a motor, said knob and said motor being alternately connectable by said clutch to a tread of said tractor means in response to a translatory movement of said knob for alternatively driving said tread by said motor or by said knob.

Claim 26

A print guide mechanism according to claim 16, further comprising a tractor means for positioning a medium for receiving printing; said tractor means having a clutch, a manually operable knob and a motor, said knob and said motor being alternately connectable by said clutch to a tread of said tractor means in response to a translatory movement of said knob for alternatively driving said tread by said motor or by said knob.

Claim 27

A print guide mechanism according to claim 16, wherein rail means, extending parallel to said shaft, are provided for supporting said carriage, and roller means are provided between said carriage and said rail means for rolling said carriage along said rail means.

Claim 28

A print guide mechanism according to claim 24, wherein said rail means comprises a pair of parallel rails, said roller means comprising at least one pair of rollers contacting each said rail at substantially 90° relative to one another about the axis of a respective rail.