US1923300A - Mechanical pencil - Google Patents

Description

A118- 22, 1933- F. c. DEL! Er AL MECHANICAL PENCIL Filed Feb. 2, 1931 Jn/em,

.ALI

a r 1 r x r 'n IP Il!" Patented Aug. 22, 1933 1,923,300 MECHANICAL PENCIL AFrank C. Deli, William D. Groseclose, and William l F. Foth, Chicago, Ill., assignors to Autopoint Company, Chicago, Ill., a Corporation of- Illinois yApplication `February 2, 1931. Serial No.4 512,807

Claims. (Cl. 1Z0-18) g Qur invention relates to pencils and more particularly to a novel form of mechanical pencil of the propel-repel type. c

n It is an object'of our invention to provide a `5 rugged, eillcient lead-.advancing mechanism, and

inaddition to providea. safety zone at each end of the longitudinal movement ofthe plunger, to limit the travel thereof and insure against'dam'- age to the parts by jamming. .The mechanism is all housed in substantially a single unit, which is forced into the pencil body for permanent positioning, the writing lead being inserted from the forward end.

Our invention will be more readily understood by reference to the accompanying drawing, in which:

Fig. 1 is a longitudinal sectional view of a penil constructed in accordance with our invenion;

Fig'. 2 isa fragmentary longitudinal sectional View of a modified form of tip construction; and

Fig. 3 is a horizontal sectional Viewtakenon the lines 3 3 of Fig. 1. Y 7 1 By reference to the drawing it will be seen that our invention comprises the barrel 10, the upper end of which is recessed 11 .to provide a lead chamber, and having a cap 12 and eraser 13. The lower end of the barrel is reduced atli and provided with a shoulder 15. The barrel also has a circular central opening 16, for the reception of the operating mechanism.

The operating mechanism consists substantial- 1y of the following described parts. A metal, conical shaped tip 17, the upper end of which is adapted to engage the shoulder 15, and the lower end of which is provided with an opening 18 through which a writing lead, not shown, is adapted to` pass. Within the` tipfl'? near the lower end, we provide an abutment or stop 19 for a purpose to be later described, and above this the tip is threaded at 20 to engage the lower, threaded end ofthe plunger guide 21. The plunger guide 2l has a longitudinal slot 22, the entire length thereof, and the upper end is tapped and threaded 23 to receive the closure plug 24. Y

Slidable within the plunger guide 21, is the plunger 25, the upper end 26 of which isbent at a right angle and projects through the'slot 22, the lower end of which is provided with a reduced portion,27,l and a head 28. The head 28 is adapted to be received by the slotted lead chuck 29, having its rear end closed by anY internal llangev 30. Thus the reduced portion 27 is permitted to slide within said chuck, but preventof the plunger.

plunger `tube 21.

ed from withdrawing by reason of the head v28. 'L

The rear face of the chuck 29 serves as a bearing for a coil spring 31 surrounding the plunger 25. The upper endof the spring 3l is adapted to seat against the lower end of the plungerxsleeve 32. Y

and is slotted 33 for a portion of its length to permit longitudinal movement of the bent end 26 Our construction further comprises the formation of a sleeve 34 having a helicalslot'35 therein, adapted to receive the bent end 26, of the plunger. The helical slot 35 is open at the upvper end to provide a safety Zone 36 in which the head 26 rotates in its upper, retracted position. Over the ,sleeve 34 we provide the friction sleeve 37, tapered at its lower end to Contact the inside of the tip 17, and its upper end seated against a thrust washer 38, secured by a tight collar 39 pressed over the upper end of the tapped The collar 39 has a smaller outside diameter than that of the friction sleeve V37 to avoidY any possible contact with the wall ofthe, circular opening 16. `It has also been found desirable to cut in said sleeve 37 a helical slot 35a extending for oneturn, justbelowthe upper end ofthe helical sleeve 34 and in the opposite direction to the slot 35. The purpose of this slot is to provide a limited degree of resilience to the upper end of this. tube to insure a tight frictional nt against the barrel. Y

The 'helically slotted sleeve V34 is adapted to llt tightly Within the outer friction sleeve 37, and the sleeve 37 is adapted to frictionally contact-the barrel walls. The sleeve 34 and friction sleeve 37as a unit rotate with the barrel, and have capacity for rotation relative to the plunger guide 21 which Vis xed to the tip, and are prevented from relative longitudinal movement by the collar 39. y

The operation of the pencil vdescribed is substantially as follows: The mechanism shown in Fig. 1 is in loading position. Assume a writing lead to be inserted into the chuck 29. The tip is grasped, for example, in the left hand, and the barrel in the right hand. Thereafter, turning the barrel in Va counter-clockwise direction will cause the plunger head 26 to travel up the helical slot 35. This for the reason that the slot 22 in the plunger guide 21, which is fixed tothe tip allows only longitudinal movement although the guide 21 rotates relative to the helical sleeve 34, friction sleeve 37 and barrel, which, when operatively joined are as a ysingle unit.

The plunger will carry with it the plunger sleeve 32, coil spring 31, and lead chuck 29 thus drawing the lead into the chamber. Continuing this movement, the upper end of the plunger sleeve 32 will eventually abut the plug 24. The plunger will be permitted further retraction until the head 26 emerges into the free zone 36. During this action however Vthe sleeve 32 has ceased movement and, the coil spring 31 is being put under tension, tending to' draw the head 26' downward. Thus when the rotation of the barrel is reversed, the head 26 will immediately enter the slot and travel downward. The continuation of this movement will eventually carry the head 26 out of the lower end of the helical slot, into another free zone 36a, and the forward movement thereof is arrested. In this position, the lead chuck will contact the shoulder 19 and the head will be projected forward through the chuck. In this position, the coilv springv 31 is again under tension, tending to push the' sleeve 32 and plunger 25 inward. As soon as the rotative movement is reversed, the head 26 will againv enter the helical slot and the head 28 will be withdrawn against the flange of the chuck, thus drawing the chuck4 inward. The longitudinal thrusts exerted inthe operation of the mechanism is taken care of by the washer '38 at the upper end, and the tapered lower end of the friction sleeve 3'7k against the'tip 17.

In Fig. 2 we have shown a slight modification 'of the tip assembly, it being understood that the device `functions in the same manner as the" preferred form. In this form, We have provided the metal tip 40, having the lead opening 41 and shoulder 42. The plunger guide 43, corresponing with the plunger guide 21 in the preferred form, is not screwed into the tip, but is secured thereto by staking in a washer 44 tightly binding the tip and tube. The washer is ,maintainedV in place by displacing a portion of metal 45 from the inner wall of the tip 40. The remaining parts are of similar construction as those heretofore described.

Thus itwill be seen that we have provided ,a simple, yet extremely efficient construction, embodying the propelling and retracting features, and in addition insuring perfect' safetyagains't injury to the parts by forcing the plunger or jamming the parts,

Obviously modifications and, variations may be Vmade in the construction herein disclosed, and we do not wish to be limited except as indicated inthe kappended claims.

We claim: f Y.

1. A mechanical pencil comprising in combination, a recessed body, -a tip, lead advancingmeans including a tubular plunger guide having Aa longitudirial slot thereinV and-a slotted plunger sleeve adapted to slide therein, a helically slotted sleeve having capacity for rotation relative to said plunger guide, a friction sleeve permanently xed -to vsaid helically slotted sleeve, aY plunger 'slidable within said plunger guide, said plunger hav,-

king a projection at one end adapted to pass ends of the said helical slot, said tip assembly being joined to said body by the sole act of forcing said friction sleeve into said recess.

2. A pencil comprising in combination, a barrel having a central recess, a tip, lead advancing means including a slotted tubular plunger guide, a tubular, slotted plunger sleeve adapted to slide within said plunger guide, a plunger, said plunger being received within vvsaid plunger sleeve and guide, and having a projection at its upper end adapted to project through the slot in said plunger sleeve and plunger guide, a sleeve havingv a helical slot formed in the length thereof adapted to receive said plunger guide, the projection on saidplunger being adapted to engage said helical slot and to travel the length of said vhelicalrslot and to be disengaged at the extreme ends thereof, means for stopping the travel, a friction sleeve permanently fixed to said helical sleeve, spring means on said plunger and Within said A'plunger guide for causing the reengagement of vsaid plunger projection with said helical slot at the extreme ends thereof, said helically slotted sleeve and said friction sleeve having capacity for rotation relative to the said plunger and plunger sleeve, said lead radvancing means. being attached to said barrel by the sole act of forcing said frictionsleeve into said recess. y

3. A pencil, comprising a barrel having a central recess, a 131D, lead advancing means including a tubular sleeve, said sleeve having a helical slot therein, a tubular, slotted plunger guide rotatable Within said helically slotted sleeve, a plunger adapted toj slide lwithin said guide, said plunger having a projection on the upper end thereof adapted to project through the slot in the guider and to travel in the helical slot from end to end thereof, spring means on said plunger for insuring the reengagement of said projection with the slot at both terminals ofthe longitudinal movement of said plunger, and a friction sleeve 4adaptedto'fit tightly over said helically slotted sleeve, said tip and associated parts being joined to said barrel by the sole act of forcing said rfriction sleeve into said recess, said plunger being moved by'relative rotation of said tip and barrel.

y 4. A1 device of the class described comprising a bodyV having a central recess closed at its upper end, a tip, lead moving mechanism'including a slotted plunger guide, a sleeve slidably fitted there-over, said sleeve having a helical slot, a plunger, slidable within said guide, said plunger having a projection at its upper end adapted to project through the slot in the guide and to be received within the helical slot, a friction sleeve immovably fitted to .said helically slotted sleeve,

tudinal movement, relative to said plunger guide and tip, and spring means onvsaid plunger for insuring the reengagement of said projection with said helical slot at both ends of the longitudinal movement of said plunger, said tip assembly being joined to said body by the sole act of forcing said frictiony sleeve into said recess, and said plunger being moved by relative rotation of said tip and said body. v

5. A propel-repel pencil having a safety zone Aat each end of the longitudinal movement of its lead-'moving element, which comprises a body having a central recess closed at its upper end, a tip, lead moving mechanism including a slotted plunger guide, a sleeve slidably fitted thereover, said sleeve having a helical slot throughout the length thereof and providing an open space at either end, a plunger, slidable within said guide,

fil

ing capacity for rotation Without longitudinal movement, relative to said plunger guide, and spring means on said plunger for insuring the rfa-engagement of said projection with said helical slot at both ends of the longitudinal movement of said plunger, said tip assembly being joined to said body by the sole act of forcing said friction sleeve into said recess.

Y FRANK C. DELI.

WILLIAM D. GROSECLOSE. WILLIAM F. FOTH.

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