US 4,030,412 AGranted

Duplicating machine

AssigneeHeyer Inc.

InventorEdward M. Springer

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Abstract

A duplicating machine has an impression roll positioned to press copy sheets against a master sheet on a drum which is rotatable by an electric drive motor through a coil spring type clutch. The clutch consists of a coil spring having an interference fit with cylindrical friction surfaces on driving and driven clutch members which are connected respectively to the motor and drum. The coil spring is helically wound in a direction to tighten the interference fit when the motor rotates the driving clutch member to turn the drum in a printing direction; conversely, the interference fit loosens when the driving end of the coil spring is held, enabling the driving clutch member to rotate freely. A tang on the driving end of the spring is positively connected to a cylindrical release collar surrounding the spring. The driven end of the spring has a positive tang connection to the driven clutch member and drum. Thus, rotation of the release collar and drum are synchronized within a range determined by the torsional elasticity of the spring. A stop arm is movable to and from a stop position engaging one or more detent recesses in the release collar. Engagement of the stop arm within one of the recesses, at the end of a printing run, automatically stops the collar. This disengages the clutch by releasing the interference fit between the spring and the driving clutch member. The drum stops at a position determined by the stopped position of the release collar. A plurality of detent recesses are circumferentially and axially spaced about and along the axis of the release collar. The stop arm is selectively engageable with one or the other of the recesses to stop the drum at different rotated positions to enable the ends of different length master sheets to clear the impression roll. A manually operable starter arm assembly releases the stop arm from the detent recess on the release collar and simultaneously closes a switch to actuate the drive motor. Conversely, when the last copy sheet is fed into the machine, the stop arm automatically drops into the selected recess to stop the release collar to disengage the clutch while simultaneously opening the switch to deactuate the driving motor and allow the drive train to coast to a stop.

In a duplicating machine having a frame, a rotatable printing drum with means for supporting a master sheet thereon, an impression roll positioned to press copy sheets against the master sheet on the drum, a support for a stack of copy sheets adjacent an inlet end of said housing, feeding means for advancing copy sheets successively from the stack into the housing between the drum and impression roll for printing from the master sheet onto the copy sheet, drive means for rotating the drum, means for automatically stopping the drum with the end of the master sheet at a predetermined position beyond the impression roll comprising in combination:

clutch means including driving and driven clutch members connected respectively to said drive means and to said drum, means for engaging said clutch members to enable said drive means to rotate said drum, a release collar connected to said driven member for rotation therewith and being rotatable with both said clutch members when so engaged, and means to disengage said clutch members and enable said drum to stop at a position corresponding to the stopped position of the release collar in response to stopping the rotation of said release collar;
stop means for said release collar including detent means on said release collar and a stop arm which is movable to and from a stop position engaging said detent means to thereby stop said release collar;
a manually movable starter arm movable to and from a start position;
means including a mechanical connection between said starter arm and said stop arm being responsive to manual movement of said starter arm to its said stop position to move said stop arm away from its said stop position and to simultaneously actuate said drive means to rotate said drum through said clutch means;
means including copy sheet sensing means having a follower sensitive to said stack of copy sheets to maintain said starter arm in its said start position while a copy sheet in said stack remains on said support;
and
said means including said copy sheet sensing means being further responsive to the last copy sheet leaving the support to automatically move said stop arm into engagement with said detent means to stop said release collar and to disengage said clutch members while simultaneously deactuating said drive means to stop said drum at a predetermined position corresponding to the stopped position of said release collar.

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Abstract

Claims16