US1966207A - Mechanical pencil - Google Patents

Description

y 10, 1934- H. H. LANG 1,966,207

MECHANICAL PENCIL Filed Feb. 23, 1932 2 Sheets-Sheet l July 10, 1934. LANG MECHANICAL PENCIL Filed Feb. 23, 1932 2 Sheets-Sheet 2 Patented July 10, 1934 UNITED STATES PATENT orl-lca IIIE'CZHANICAL PENCIL Illinois Application February 23, 1932, Serial No. 594,434 7 Claims. (01. 120-18) This invention relates to an improvement in mechanical pencils and consists of the matters hereinafter described and more particularly pointed out in the appended claims.

The improved pencil is of the advance-retract class and more specifically of that type of such pencils in which the' lead approximates the length of the pencil.

The object of the invention is to produce a pencil of the kind of simple and economical construction, in which magazines are provided to contain several extra leads with but slight increase in the diameter of the pencil barrel. This and other objects and advantages of the invention will appear more fully as I proceed with my specification.

In the drawings, which, as will be obvious are made on an exaggerated scale in order the more clearly to illustrate the details of construction,

Figure 1 is a longitudinal central section of the upper part of the pencil.

Figure 2 is a like section of the lower part of the pencil.

Figure 3 is a perspective view of the lead tube with the plunger therein.

Figure 4 is a perspective view of the tip of the pencil.

Figure 5 is a transverse section through the pencil in a plane indicated by the line 5-5 of Figure 1.

Figure 5a, is a detailed sectional view on an exaggerated scale in a plane indicated by the line 5w5a of Figure 5.

Figure 6 is a transverse section through the pencil in a plane indicated by the line 66 of Figure 1. m

Figure 7 is a transverse section through the pencil in a plane indicated by the line '7-'7 of Figure 1.

Figure 8 is a transverse section through the pencil ina plane indicated by the-line 8-8 of Figure 1.

Figure 9 is a transverse section through the pencil in a plane indicated by the line 99 of Figure 2.

Referring now to that embodiment of the invention illustrated in the drawings:10 indicates the barrel of the improved pencil. This may be made of any suitable material or composition now in use for such pencils. The barrel has a longitudinally extending central bore or recess 11' extending from its tip end to its head end. The tip end of the barrel is tapered, as shown at 10a, and is formed to receive the stem 10b of. a metal tip 100, tapered to correspond to the taper of the barrel part 10a. The metal tip has a bore or recess 10d in axial alignment with the recess 11 of the barrel but reduced in diameter so that it is little greater than that of the lead which it is to receive.

So that the metal tip may be held non-rotatively in the end of the barrel, its stem 101), otherwise cylindrical, is fiattened on one side, as indicated at 10e,the recess or bore in the tapered part 100. of the barrel being formed with a similar cross section.

Within the recess 11 in the barrel is located a tube 12 having a spiral slot 13 running throughout its length in a familiar manner. Within said tube 12 is located a tubular clutch 14 which at its bottom end is adapted to grip a lead and which is provided near its top end with a laterally projecting horn 15 which engages within the spiral slot 13 of said tube.

The barrel 10 has formed in it and extending longitudinally thereof, four slots or chambers 16, 16, 16, 17, which are disposed radially about the recess 11, opening thereinto and, as shown, spaced about the axis of said recess at angles of degrees. The slot 17 is substantially rectangular in cross section (see Figures 1, 6 and 7) and is engaged by the horn 15 of the clutch 14, said horn extending through the spiral slot 13 beyond the tube 12 and into said slot to have guiding relation therewith to hold the clutch non-rotative as it is moved from end to end of the barrel by means of the rotation of the tube 12. The slot 17 thus acts as a key-way for the horn 15, permitting longitudinal movement but preventing lateral movement thereof. The other three slots or chambers 16 are rounded in cross section and constitute magazinesto retain extra leads for use in the pencil.

The tube 12 is designed to be rotated by a drive ferrule 18 rotatably mounted on the top end of the barrel. Said ferrule has a head 19 which covers the space occupied by the several magazines 16 and the key-way 17 in the barrel. It also has a centrally disposed tubular stem 20 which depends from said head into the barrel where it embraces and is operatively locked to the top end of the spirally slotted tube 12. As shown, the stem 20 is deformed on one side to provide a detent 21 (see Figures 1 and 7) whichv has locking engagement within a hole or aper ture 22 formed in the tube 12. Obviously, the rotation of the ferrule 18 on the head of the barrel will impart rotative movement to the spirally slotted tube 12; and by reason of the engagement of the spiral slot 13 with the horn 15, a longitudinal movement of the horn 15 in the key-way 17 will be brought about, thereby producing a to and fro movement of the clutch 14.

An eraser 23 is mounted in a tubular holder 24 which is removably engaged upon the ferrule 18 in a familiar manner. The construction is such (as shown in Figure 5, for example) that a sufiicient friction will be provided between the tubular holder 24 and the ferrule 18 that rotative movement of the tubular holder 24 will impart rotative movement to the ferrule 18. To retain the ferrule 18 on the barrel, it is provided with an inwardly extending, annularly indented rib 18a which is engaged in a suitable groove in the barrel.

At the head of the barrel and below the head 19 of the ferrule 18 is located a transversely disposed washer 25. Said washer is perforated in line with the magazine slots 16 of the barrel, as indicated at 26; but it is imperforate in line with the key-way 17 in which the horn 15 operates. This prevents one, when loading the pencil, from inserting a lead into the key-way 17, with the thought that it is one of the magazine recesses in the pencil barrel. Said washer is fixed against rotation by a tongue 25a cut from it and bent at right angles thereto. Said tongue is of the width of the key-way 17 and is engaged therein. This locks the washer against rotative movement on the head of the barrel. The perforations in the washer 25 which communicate with the magazines 16 are normally covered by the head 19 of the ferrule 18, but may be uncovered for the purpose of loading the magazines or for the purpose of withdrawing a lead from one or the other of them, by reason of a perforation 19a. in the head 19 of the ferrule 18, which perforation may be brought into line with one or the other magazines 16 when desired.

It will be obvious that when the ferrule 18 is rotated to rotate the spirally grooved tube 12 to advance or retract the lead, the perforation 19a in the head 19 of the ferrule 18 will be successively brought into line with the several holes 26 in the washer 25. If the pencil be held with the point pointing downward, during this rotative movement of the pencil, no harm will be done; but, if it be held with the point up, as is more apt to be the case, the leads will tend to fall through the openings 26 in the washer and through the opening 19a in the head of the ferrule each time it comes to register with an opening 26 in the washer. This would tend to produce a shearing or cutting action on the projecting ends of the leads which would be a detriment. To overcome this difliculty, the opening 19a is countersunk on the bottom side, as shown in Figures 5 and 5a. In addition, the bottom end of the eraser 23 is held snugly against the head 19 of the ferrule so that the eraser projects somewhat into the said opening 19a, as indicated at 19b in Figure 1. By this construction, there is a sort of cam action produced by the countersunk inclined edges of the opening 19a and by the inwardly projecting substance of the eraser, to engage the projecting ends of the leads and force them back into their respective magazines each time the opening 19a is brought to register with the holes 26 in the washer 25.

27 indicates a lead which has its upper end engaged with the lower end of the clutch 14. Within the clutch is a plunger 28. Said plunger extends above the horn 15 of the clutch and is provided a short distance therefrom with a right angular bend which presents a laterally projecting horn 29 at the top end of said plunger. Said horn extends through a longitudinal slot 29a in the clutch 14 above the horn 15 and through the spiral slot 13 of the tube 12 into the key-way 17 in the barrel. The slot 29a. in the clutch 14 limits the movement of the horn 29 with reference to the horn 15 of the clutch and permits movement of the horn 29 towards the horn 15 when a lead is to be ejected from the clutch, in a manner presently to be described; but generally, and except at such time, the plunger 28 travels with the clutch 14 in the to and fro movement thereof brought about by the rotation of the ferrule 18. l

The bottom end of the tube 12 terminates somewhat short of the inner end 10b of the metal tip 100. When the bottom end of the clutch has nearly reached the tip end of the pencil, the horn 15 of said clutch will approach the bottom end of the tube 12 and will finally pass from the slot 13 and beyond the end of the tube 12 until it is arrested by engagement against the inner end of the stem 10b. The horn will still, however, be engaged in the key-way 17. Further rotation of the tube 12 will be ineffective to advance the clutch 14 through the tip. It will, of course, be understood that when the parts come to this position, the lead carried by the clutch will be nearly all used up. Further rotation of the tube 12 will advance the plunger 28 through the clutch, this movement being brought about by the engagement of the spiral slot with the horn 29 of said plunger and, being permitted by the slot 29a in the clutch 14. In this fashion the plunger may be advanced so as to move longitudinally within the clutch and finally ejecting the small piece of lead still retained by the clutch, beyond the same and out through the tip of the pencil.

The length of the tube 12 is so designed that its bottom end leaves a space between it and the inner end of the stem 10b to barely accommodate the two horns 15 and 29 when both have passed out of the slot 13. The fit, however, is so close that continued rotation of the tube 12 which is permitted by reason of the elasticity of the tube 12 lengthwise will cause a clicking noise as the open 'end of the slot 13 passes the horn 29,said click indicating that the pencil is empty and requires a new lead.

To reload the pencil, the tube 12 is rotated in the reverse direction, which retracts the plunger. When it has reached the limit of its relative movement in the clutch 14, a continued rotative movement of the tube 12 will withdraw the clutch back to bring its horn into engagement with the spiral slot 13. Then the clutch and plunger by continued reverse rotation of the tube 12 will be withdrawn to the top of the barrel, after which a new lead may be inserted into the tip and dropped into the barrel and then by a push be I engaged with the clutch.

It will be noted that in the operation of advancing and retracting the lead, the clutch is held against rotative movement by the engagement of its horn 15 in the key-way. Thus, the lead, instead of being rotated, as in mechanical pencils of the kind heretofore made, is held against rotation. And this is an obvious advantage, since the point of the lead, as formed or worn, will always be presented to the surface 14 written upon at the same angle.

The clutch 14, with its horn 15, is preferably made from a blank of sheet metal suitably cut so that when rolled into tubular form, it will present the parts as shown in Figure 3. The horn 15 is thus made of two rounded semi-cylindrical sections 15a, 15a. By this construction the horn is adapted to yield transversely. It may thus be made of such diameter as a whole as to engage both the key-way 17 in the barrel 10 and the slot 13 in the tube 12 with sufiicient closeness that the clutch may be held against slippage due either to loose play of the horn in the key-way or in the slot 13. As a result, a firm unyielding point is always presented to the surface written upon.

The eraser 23 should preferably have some means to present a stop to limit its inward movement in the tube 24 so as to bring its inner end into proper engagement against the head 19 of the ferrule 18. To this end I provide on the eraser, as shown in Figure 1, a split ring which is adapted to engage and lock in one of the grooves in the said tube 24.

I claim as my invention:

1. In a pencil, in combination with a barrel having a longitudinal cylindrical recess therein, a plurality of slots in said barrel radially disposed about said recess, one of said slots opening into said recess and constituting a key-way, a spirally slotted tube rotatable in said longitudinalrecess, a lead clutch longitudinally movable in said tube, said lead clutch having a horn extending through the slot in said tube and engaged in said key-way beyond said tube, said horn being constructed to closely but yieldingly engage said slot and said key-way, and means for rotating said spirally slotted tube.

2. In a pencil, in combination with a barrel having a longitudinal cylindrical recess therein, a plurality of slots in said barrel radially disposed about said recess, one of said slots opening into said recess and constituting a key-way, a spirally slotted tube rotatable in said longitudinal recess, a lead clutch longitudinally movable in said tube, said lead clutch having a horn extending through the slot in said tube and engaged in said key-way beyond said tube, said horn being constructed to closely but yieldingly engage said slot and said key-way, and a ferrule rotatably mounted on the end of said barrel and having interlocked engagement with said slotted tube.

3. In a pencil, in combination with a barrel having a longitudinal cylindrical recess therein, a plurality of slots in said barrel radially'disposed about and opening into said recess, said recess and slots opening through the head of said barrel, one of said slots constituting a key-Way and the others, magazines for leads, a spirally slotted tube rotatable in said longitudinal recess, a transverse washer at the head of the barrel closing said key-way but having openings to expose said magazines, a revolvable ferrule having a head closely engaging said washer and provided with an opening adapted to be brought to register with the openings in said washer, means rigidly connecting said ferrule with said tube, and a lead clutch longitudinally movable in said tube and provided with a horn engaging with the slot in said tube and with the key-way in said barrel.

4, In a pencil, in combination with a barrel, a

longitudinally extending recess therein, a plurality of slots in said barrel radially disposed about and opening into said recess, said recess and slots opening through the head of. said barrel, one of said slots constituting a key-way and the others magazines for leads, a transverse washer at the head of the barrel closing said key-way and having openings to expose said magazines, a ferrule having a head provided with a hole adapted to be brought to register severally with the openings in said washer, said hole being countersunk on the side towards said magazines, and means rigidly connecting said head with said slotted tube. I

5. In a pencil, in combination with a barrel, a longitudinally extending recess therein, a plurality of slots in said barrel radially disposed about and opening into said recess, said recess and slots opening through the head of said barrel, one of said slots constituting a key-way and the others magazines for leads, a transverse wash-- er at the head of the barrel closing said key-way and having openings to expose said magazines, a ferrule having a head provided with a hole adapted to be brought to register severally with the openings in said washer, said hole being countersunk on the side towards said magazines, a member mounted adjacent said head and forming a backing for said hole therein, and means rigidly connecting said head with said slotted tube.

6. In a pencil, a barrel having a longitudinal cylindrical recess therein with a plurality of slots radially disposed about and opening directly into said recess, said slots being closed at the point end of the barrel and being open at the head of the barrel, one of said slots constituting a keyway, a spirally slotted tube rotatable in said longitudinal recess, a lead clutch longitudinally movable in said tube, said lead clutch having a horn extending through the slot in said tube and engaged in said keyway beyond said tube, a ferrule rotatably mounted on the head end of said barrel and having interlocked engagement with said slotted tube, said ferrule having a head provided with an aperture adapted to be brought into alignment with the slots in said barrel.

7. In a pencil, a barrel having a longitudinal cylindrical recess therein with a plurality of slots radially disposed about and opening directly into said recess, said slots being closed at the point end of the barrel and being open at the head of the barrel, one of said slots constituting a keyway, a spirally slotted tube rotatable in said longitudinal recess, a lead clutch longitudinally mov able in said tube,said lead clutch having a horn extending through the slot in said tube and engaged in said keyway beyond said tube, a ferrule rotatably mounted on the head end of said barrel and having interlocked engagement with said slotted tube, said ferrule having a head provided with an aperture adapted to be brought into alignment with the slots in said barrel, and a tube member including a backing member engaged against said head, said tubular member frictionally embracing said ferrule.

HERBERT H. LANG.

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