Compensating platen for printing machines

Claim 2

A printing machine for printing a form by means of printing devices, in which forms of various thicknesses may be accepted, comprising: a bed, means operatively associated with said bed projecting from the bed; a carriage movable through a printing stroke across the bed from a first position to a second position; a pad means in the bed for underlying a form in a printing position, said pad means having a reference surface related to the bed and the height of the printing characters projecting therefrom; a platen and means supporting the platen in a non-printing position on the carriage spaced from said pad means by a first distance; said platen being movable from the nonprinting position to any one of a plurality of printing positions in which said platen is spaced from said pad means by a distance which is less than said first distance and which is determined by the thickness of the form disposed on said pad means; actuating means on the carriage for moving the platen towards the pad means to one of a plurality of printing positions, said platen in said one of said plurality of printing positions being disposed in engagement with a form disposed on said pad means; catch means on the carriage movable between a first position retaining said platen against movement between the nonprinting and printing positions and a second position in which said catch means is ineffective to retain said platen against movement; trip means operatively associated with said catch means for moving the catch means from its first position to its second position during initial movement of the carriage from the first position to thereby release said platen for movement from said nonprinting position to any one of said plurality of printing positions; and means operatively associated with said catch means for moving the catch means from the second position to the first position when the platen is in one of said printing positions; a baising means on the carriage for normally urging the platen to the nonprinting position; and said actuating means comprising means for acting in opposition to the biasing means and for moving the bearing means toward said pad means when said catch means is in its second position to effect movement of said platen from the nonprinting position to any one of said plurality of printing position.

Claim 3

A printing machine for printing a form by means of printing devices, in which forms of various thicknesses may be accepted, comprising: a bed, means operatively associated with said bed for establishing printing characters projecting from the bed; a carriage movable through a printing stroke across the bed from a first position to a second position; a pad means in the bed for underlying a form in printing position, said pad means having a reference surface related to the bed and the height of the printing characters projecting therefrom; a platen and means supporting the platen in a non-printing position on the carriage spaced from said pad means at a first distance; said platen being movable from the nonprinting position to any one of a plurality of printing positions in which said platen is spaced from said pad means by a distance which is less than said first distance and which is determined by the thickness of the form disposed on said pad means; actuating means on the carriage for moving the platen towards the pad means to one of the plurality of printing positions, said platen in said one of said plurality of printing positions being disposed in engagement with a form disposed on said pad means; catch means on the carriage movable between a first position retaining said platen against movement between the nonprinting and printing positions and a second position in which said catch means is ineffective to retain said platen against movement; trip means operatively associated with said catch means for moving the catch means from its first position to its second position during initial movement of the carriage from the first position to thereby release said platen for movement from said nonprinting position to any one of said plurality of printing positions; and means operatively associated with said catch means for moving the catch means from the second position to the first position when the platen is in one of said printing positions; said actuating means including a plurality of ratchet teeth, said catch means comprising a pawl; and wherein a biasing means on said carriage normally urges the catch means to the first position for maintaining the pawl in engagement with the ratchet teeth; whereby movement of the catch means to the second position withdraws the pawl from engagement with the ratchet teeth to release the actuating means, and movement of the catch means to the first position under the influence of the biasing means restores the pawl into engagement with the ratchet teeth to lock the actuating means during movement of the carriage.

Claim 4

A printing machine for printing a form by means of printing devices, in which forms of various thicknesses may be accepted, comprising: a bed, means operatively associated with said bed for establishing printing characters projecting from the bed; a carriage movable through a printing stroke across the bed from a first position to a second position; a pad means in the bed for underlying a form in printing position, said pad means having a reference surface related to the bed and the height of the printing characters projecting therefrom; a platen and means supporting the platen in a non-printing position on the carriage spaced from said pad means at a first distance; said platen being movable from the nonprinting position to any one of a plurality of printing positions in which said platen is spaced from said pad means by a distance which is less than said first distance and which is determined by the thickness of the form disposed on said pad means; actuating means on the carriage for moving the platen towards the pad means to one of the plurality of printing positions, said platen in said one of said plurality of printing positions being disposed in engagement with a form disposed on said pad means; catch means on the carriage movable between a first position retaining said platen against movement between the nonprinting and printing positions and a second position in which said catch means is ineffective to retain said platen against movement; trip means operatively associated with said catch means for moving the catch means from its first position to its second position during initial movement of the carriage from the first position to thereby release said platen for movement from said nonprinting position to any one of said plurality of printing positions; and means operatively associated with said catch means for moving the catch means from the second position to the first position when the platen is in one of said printing positions; said actuating means including a plurality of ratchet teeth, said catch means comprising a pawl; and wherein a biasing means on said carriage normally urges the catch means to the first position for maintaining the pawl in engagement with the ratchet teeth; whereby movement of the catch means to the second position withdraws the pawl from engagement with the ratchet teeth to release the actuating means, and movement of the catch means to the first position under the influence of the biasing means restores the pawl into engagement with the ratchet teeth to lock the actuating means during movement of the carriage.

Claim 5

A printing machine as set forth in claim 1 including means adjacent the end of the bed for moving the platen from said printing positions to said nonprinting position in response to movement of said carriage to its second position.

Claim 6

A printing machine as set forth in claim 2 further including means adjacent the end of the bed for moving the platen from said printing positions to said nonprinting position in response to movement of said carriage to its second position.