Mechanical pencil, especially for thin leads

Claim 1

In a mechanical pencil, especially for thin leads, a combination comprising elongated tubular casing means having a lower end; resilient clamping means arranged substantially coaxially within said casing means spaced from said lower end and movable between normally open position in which it is disengaged from a lead passing through said clamping means and a clamping position in which it clamps said lead, said clamping means including a connecting portion remote from said lower end and a plurality of circumferentially spaced force-multiplying arms extending from said connecting portion towards said lower end and defining in the region of said connecting portion a lead passage; tubular lead guide means projecting coaxially beyond the lower end of the tubular casing means and being guided therein movable in axial direction, said tubular lead guide means being constructed for frictionally engaging a lead passing through said clamping means and said tubular lead guide means; transmission means between said tubular lead guide means and said clamping means for transmitting, during writing or drawing and exertion of axial pressure and slight inward movement of the tubular lead guide means, a corresponding pressure to said arms of said clamping means to move the latter to said clamping position in which said arms multiply the applied force and engage the lead in said lead passage with an increased force, so as to prevent inward movement of the lead; and restoring means for moving said lead guide means upon cessation of said axial pressure in outward direction relative to said casing means while said clamping means return to said open position thereof.