GB807667A - Mechanical pencil feed mechanism - Google Patents

Abstract

807,667. Pencil holders. SCRIPTO Inc. April 8, 1957 [Oct. 25, 1956], No. 11368/57. Class 146(3) A mechanical pencil comprises a guide tube 24, a lead-gripping clutch member 26 and a propelling member 27 slidably disposed in the guide tube, the propelling member having a shank portion 44 slidable within the clutch member 26 and formed with shoulders 46 and 47 facing rearwards and forwards respectively, the clutch member 26 having ears 48 formed thereon to abut the shoulder 46 and a flexible arm portion 49 extending rearwards from the ears to the shoulder 47, the inner face of the guide tube 24 holding the arm 49 in abutment with the shoulder 47 so that the clutch member is held against the propelling member for movement therewith within the guide tube, except near the front end thereof at which the guide tube permits such outward displacement of the arm 49 as to release the propelling member 27 for separate movement to eject a spent lead from the clutch member 26. The propelling member 27 also includes at its rear end a nut portion 43 having a toothed radial lug 45 which projects through a longitudinal slot in the guide tube 24 and engages threads 31 formed on the inner surface of a tube 28 disposed outside and concentrically with the guide tube for rotation relative thereto and to the barrel 10 of the pencil thus causing longitudinal displacement of the propelling member 27 When the front end of the clutch member 26 reaches the bottom of a bore 22 in the point section 11 of the barrel a boss 50 formed on the arm 49 coincides with an aperture 51 in the guide tube 24 so that on continued rotation of the tube 28 the shoulder 47 on the propelling member shank 44 forces the arm 49 outwards thus allowing the propelling member to be advanced until the ears 48 abut the shoulder 47. At this point the front end of the shank 44 has passed completely through the tubular portion of the clutch member 26 thus ejecting the last portion of lead L remaining therein. The tube 28 has longitudinal recesses 30 on its outer surface to accommodate spare leads. A washer 33 is fitted over the rear ends of the tubes 24, 28 and is keyed to the latter by leg portions 34; a retaining pin 38 is passed through the rear end of the guide tube 24 and rests upon the upper surface of the washer 33. A sleeve 35 is attached to the washer by dimpling as at 36, which sleeve is a friction fit in an aperatimig sleeve 12 having a plastic cover 14 by rotation of which in relation to the barrel 10 the tube 28 is rotated in relation to the guide tube 24, the latter being fixed in the point section 11. Lugs 52 are formed on the underside of the washer 33 having radially extending triangular sides facing in the direction in which the tube 28 is rotated for. retracting the propelling member 27. One of the lugs 52 abuts laterally against the lug 45 on the propelling member 27 when the latter is fully retracted, so as to prevent the nut portion 43 from jamming against the forward face of the washer 33 and damaging the threads 31. The sleeves 12, 35 carry erasers in their rear ends.