Patent GB-198041-A (GB)
Title: Improvements in and relating to the manufacture of mechanical pencils
IPC: B43K21/08
Filed: 1922-02-22
Abstract: 198,041. White, A. E., (Realite. Pencil Manufaturing Co.). Feb. 22, 1922. Pencil-holders; erasers.-In a pencil holder the forward end of the lead-propelling plunger engages with an axial spirally-grooved tube rotatably mounted in the barrel, the rear end of the plunger being provided with a head adapted to engage with a guiding portion of the barrel so as to allow of longitudinal but not rotary movement. The barrel may be made of metal, wood. or composition. Means for holding and protruding an eraser are also provided. The barrel A, Fig. 1, is fitted with a tip 15 carrying a spirally-grooved tube 17 which extends into the bore of the barrel, the grooves . co-operating with laterally-extending portions 20 on a plunger 19. The plunger is extended beyond the tube 17 and is provided with a flattened head 20<1> engaging in an angular guide-way 12 formed in a reduced portion 10 of the bore of the barrel. Beyond the bore 10, a partition 9 is provided to close the end of a receptacle 8 for spare leads, the outer end being closed by an eraser 7 carried by a sleeve frictionally held on the rear end of the barrel. The barrel may be formed of a composition, preferably one that is rendered plastic by heat and pressure, such as one of the phenol condensation products. Two complementary parts of the section shown in Fig. 3, ara formed in the same mould, a tongue and groove in each section being provided to facilitate centring. The assembled parts are placed in a mould and subjected to heat and pressure to fuse them together. As shown in Fig. 5, a metal barrel 110 is provided with receptacles for spare leads formed from a metal tube 117, the wall of which is concaved inwardly to form a number, preferably three, of radially arranged ridges 118 frictionally engaging the inner wall of the barrel; and also to leave a central space 120 which receives a similar-shaped head 116 on the end of the plunger 114 to prevent rotation, but allow longitudinal movement thereof. The lower end of the member 117 is of the same cross-section as the barrel to provide a closure for the receptacles and a throated entrance to the central passage. The rear end of the barrel which extends beyond the end of the member 117 receives a sleeve 123 provided with a central portion of reduced diameter, into which screws a plug 126 adapted for movement to adjust an eraser in the sleeve. In a modification of this device, the barrel is made of wood or composition, and the member 117 abuts on a shoulder formed therein. As shown in Figs. 14 and 15, the spirally-grooved tube 219 carried by the tip is telescoped into a tube 225 which is formed of elongated cross-section at its rear end to prevent the rotation of the flattened head 229 of the plunger 230. The tube 225 is spaced from the barrel to form an annular receptacle. for spare leads, the lower end thereof being closed by a plug 235 which screws on to the tube 225 and is removable after the tip has been detached. The rear end of the tube 225 passes through a similar shaped aperture in a plate 236 closing the end of the receptacle and which is also apertured at 237 to provide a neck 238 and head 239 detachably engaged bv the bent-over extensions 245, 246 of the head of a pocket clip 242 which is accommodated in a slot in the barrel, so that the tube 225 is held against rotation. In a modification of this arrangement, the barrel, formed from wood or composition, is relatively solid, and is provided with a bore having two different diameters, the larger one at the rear end accommodating the tube 225 which telescopes upon the spirally-grooved tube rotatably mounted in. the narrower bore. The bore at the rear end is further enlarged on opposite sides to form receptacles for spare leads. In both these modifications, an eraser 212 is held in a tapered slotted cup 210 forced into the rear end of the barrel, the upper ends of the slotted walls being inturned to bite into the eraser. To eject the cup to enable it to be fitted with a fresh piece of eraser, the plunger is screwed back until the head comes into contact with the bottom of the cup. Further movement of the plunger results in the tip being pushed down off the barrel slightly as it is fitted less tightly than the cup, and if the tip is then pushed home, the cup will be forced out of the barrel. In all the modifications, the propulsion. of the lead is obtained by rotating the tip ard consequently the spirally-grooved tube ralatively to the casing, and, by removing the tip, tube, and plunger from the barrel and unscrewing the plunger, a new lead can be inserted in position. An enlarged space is provided beyond the end of the spirally-grooved tube, either in the barrel itself or in the larger telescoping tube, into which the head of the plunger enters at the end of its feeding movement to enable it to rotate freely and prevent strain of the parts in case of overwinding.