Writing implement which lengthens and shortens when actuated

A writing implement comprising a housing, a writing cartridge movably arranged in said housing, a depressor configured as an extension of the housing, and a control unit having a first switching cam for displacing the writing cartridge between a first position in which the cartridge tip is extended out of the housing for writing, and a second position in which the writing cartridge is retracted within the housing, wherein the writing implement in the first position has an overall length suitable for writing and in the second position is shortened;

• wherein the control unit has a second switching cam which interacts with the depressor;
• wherein the depressor can be actuated in the same pressing direction to displace the writing cartridge both into the first position and into the second position, wherein the second switching cam is configured to fix the depressor in the second, telescoped and shorted position, and wherein the second switching cam is configured in such a way that, starting from the telescoped position, the depressor is unlocked when the depressor is actuated in the pressing direction and can be extended out of a rear end of the housing into the first position.