Device for clamping the trailing end portion of a sheet to a drum

Claim 1

A device for clamping the trailing end portion of a sheet mounted on the peripheral surface of a rotating drum comprising: a. clamping means disposed within an opening in the drum surface and mounted for pivoting between an inner position and an outer position, said clampling means comprising: i. a plurality of plate members each having a free end with an adjacent recess; ii. hook means on each of said plate members for hooking the trailing end of the sheet when brought into contact therewith; and iii. spring means for urging said plate members toward said inner position; b. hold-plate means disposed within said opening adjacent to said clamping means and mounted for pivoting between an inner position and an outer position, said hold-plate means comprising: i. a pivoted hold-plate disposed adjacent said plate members in a position in which said hook means extend thereby outwardy of said opening; ii. stop means on said hold-plate engaging the free ends of said plate members for preventing said clamping means from pivoting to its inner position; and iii. spring means for urging said hold plate toward its outer position; c. a shaft mounted for rotation ajacent said drum; d. rotating means for rotating said shaft; e. spring clutch means for operatively connecting, when engaged, said rotating means and said shaft to urge said shaft to rotate; f. lock means for maintaining said spring clutch means disengaged; g. sheet hold-down means mounted on said shaft for rotation therewith and including roller means thereon for pressing said sheet against the periphery of said drum and bringing the trailing end of said sheet into contact with said hook means for hooking thereby; and h. means responsive to the rotation of said drum for engaging said spring clutch means when said lock means is released, to urge said shaft to rotate whereby said roller means, urged to rotate with said shaft, upon bringing the trailing end of the sheet into contact with said hook means in said opening, pivots said hold-plate means to its inner position causing the stop means thereon to enter the recesses adjacent the free ends of said plate members permitting said clamping means to pivot to its inner position drawing the trailing end portion of said sheet into said opening and maintaining said sheet in contact with the surface of the drum.

Claim 2

A device for clamping the trailing end portion of a sheet mounted on the peripheral surface of a rotating drum comprising: a. clamping means disposed within an opening in the drum surface and mounted for pivoting between an inner position and an outer position, said clampling means comprising: i. a plurality of plate members each having a free end with an adjacent recess; ii. hook means on each of said plate members for hooking the trailing end of the sheet when brought into contact therewith; and iii. spring means for urging said plate members toward said inner position; b. hold-plate means disposed within said opening adjacent to said clamping means and mounted for pivoting between an inner position and an outer position, said hold-plate means comprising: i. a pivoted hold-plate disposed adjacent said plate members in a position in which said hook means extend thereby outwardy of said opening; ii. stop means on said hold-plate engaging the free ends of said plate members for preventing said clamping means from pivoting to its inner position; and iii. spring means for urging said hold plate toward its outer position; c. a shaft mounted for rotation ajacent said drum; d. rotating means for rotating said shaft; e. spring clutch means for operatively connecting, when engaged, said rotating means and said shaft to urge said shaft to rotate; f. lock means for maintaining said spring clutch means disengaged; g. sheet hold-down means mounted on said shaft for rotation therewith and including roller means thereon for pressing said sheet against the periphery of said drum and bringing the trailing end of said sheet into contact with said hook means for hooking thereby; and h. means responsive to the rotation of said drum for engaging said spring clutch means when said lock means is released, to urge said shaft to rotate whereby said roller means, urged to rotate with said shaft, upon bringing the trailing end of the sheet into contact with said hook means in said opening, pivots said hold-plate means to its inner position causing the stop means thereon to enter the recesses adjacent the free ends of said plate members permitting said clamping means to pivot to its inner position drawing the trailing end portion of said sheet into said opening and maintaining said sheet in contact with the surface of the drum.