US2506917A

US2506917A - Mechanical pencil

Info

Publication number: US2506917A
Application number: US616497A
Authority: US
Inventors: Keith T Bleuer
Original assignee: Individual
Current assignee: Individual
Priority date: 1945-09-15
Filing date: 1945-09-15
Publication date: 1950-05-09
Anticipated expiration: 1967-05-09

Description

May 9, 1950 K. T. BLEUER MEcHANxcAL. PENcL Filed Sept. 15, 1945 Patented May 9, 1950 UNITED STATES PENT OFFIC 19 Claims.

My invention relates to mechanical pencils and more particularly to such pencils of the magazine type. By a mechanical pencil I mean a pencil which is so constructed that, by suitable manipulation thereof by the user, lengths of lead or other writing material in stick form are propelled from the tip of the pencil, and by a magazine type mechanical pencil I mean a pencil having a magazine for sticks of writing material or leads and which functions on repeated operations of the lead propelling means of the pencil to successively feed leads out of the tip of the pencil from the magazine without the necessity of manually refilling the pencil in any way successively for each lead to be propelled through the tip of the pencil.

It is an object of my invention to provide an improved lead propelling mechanism which may be used in a mechanical magazine pencil. More particularly it is an object to provide such an improved mechanism that includes a lead propeller which abuts the ends of the leads in a pencil to push the leads toward the tip of the pencil whereby there can be no slippage between the propeller and the leads. It is contemplated that the lead propeller shall preferably function to push a lead a predetermined distance toward the tip of the pencil and under continued operation of the manual operating means of the pencil shall move out of the way for propelling a stick of lead and back to its original position for propelling another stick of lead toward the tip of the pencil.

It is a further object of my invention to provide two such lead propellers in a mechanical pencil with the propellers and the mechanism for moving them being so arranged that one of the lead propellers is moved in one direction to propel a lead toward the tip of the pencil while the other propeller is moved in the opposite direction back toward its original position and out of position for acting on a stick of lead. It is contemplated that with such an arrangement of two propellers, there may be little lost movement of the manual operating means of the pencil which does not cause a corresponding movement of a stick of lead out of the tip of the pencil, as compared to a pencil construction having only one such propeller and in which there would be a lost movement of the manual operating means of the pencil corresponding to the movement of the propeller back to its original starting position from its position at which it is moved out of contact with a lead for propelling it and after it has propelled the stick of lead the predetermined distance.

It is a more specific object of my invention to provide such a mechanical pencil in which a helical element is provided for moving one of the propeller elements in one direction and in which another helical element is provided for providing a corresponding movement of the other propeller element in the opposite direction. It is contemplated that the helical elements shall preferably form tracks for the propeller elements and that the propeller elements may be caused to move in the tracks by a manually rotatable element slidably carrying the propeller elements. y

It is another object of my invention to provid in connection with such a magazine pencil having a propeller element movable forwardly for propelling a stick of lead and back to its original position after having propelled the lead a predetermined distance, means for providing a gap between consecutive leads from the magazine at the point in the lead channel at which the propeller element enters to allow the entrance of the propeller element into the lead channel. It is an object in connection with a mechanical pencil having two propeller elements as above described to provide means for preventing a feed of leads from the magazine as each of the lead propellers completes its return movement and just prior to the entrance of the propeller into the lead channel into its starting position to provide such a gap between consecutive leads to allow the lead propeller to enter the channel. It is contemplated that spring means adapted to act on the leads as they feed from the magazine and actuated by the propellers as they return to their starting positions may be used for carrying out this object.

It is also an object of the invention to provide an improved method for propelling leads in a mechanical pencil, such method being carried out by the manner of functioning of the propeller mechanism as above described, but the method itself, it being understood, being independent of any particular construction of mechanical pencil mechanism.

My invention consists of the novel methods, constructions, arrangements and devices to be hereinafter described and claimed for carrying out the above stated objects and such other objects as will appear from the following description of a certain preferred embodiment of mechanical pencil illustrated in the accompanying drawing, wherein:

Fig. 1 is a longitudinal sectional View of a mechanical pencil embodying the principles of the invention; and

Fig. 2 is a fragmentary side view of the manually operated element of the pencil carrying the propeller elements as seen from the left of Fig. 1.

Figs. 3, 4, 5 and 6 are sectional views taken respectively on lines 3 3, 4 4, 5 5, and 6-6 in the directions indicated.

The same characters of reference designate the same parts in the several views of the drawing.

Referring now to the drawing, it will be observed that the illustrated pencil comprises an outer casing IQ which is preferably madeof Bakelite or any suitable plastic. The outer surface of the casing may be fiat sided, the illustrated casing I being provided with twelve flat sides I I as shown, to facilitate the holding of the pencil by the user. Tubular elements i2 and I3 are provided within the casing it. The element I2v is disposed in the forward end of the pencil, that is, the end adjacent the writing point hereafter to be described, and the element I3 is disposed in the rear end of the-pencil and the eiements I2 and I3 abut in the u central region of the pencil as shown. The tubular element I2 is provided with a helical slot I4 therein which is adapted to function as a-track for a lead propelling element, as will be described hereinafter. rhe tubular element I3 has considerable less thickness than the element I2 and i'sfprovided to act as a bearing sleeve for receiving certain rotatable parts therein hereinafter to be described. The tubular elements I2 and I3 may vbe cast within the casing I3 when the casing is made to fiX the elements therein or the elements may be fixed within the casing by any other suitable method, such as by providing the tubular elements with a drive't in the casing and driv'- ing them in the casing after the casing has previously been east.

A tip I5 is provided for the pencil. The tip has a sleevelike portion I6 which fits over the forward end IT of the tubular element I2, and the tip is fixed with respect to the tubular element and thereby with respect to the casing I0 by being threaded on the forward end I'I of Ithetubular element I2. The tip is provided with a central cylindrical cavity I8 therein extending longitudinally of the tip, and this cavity is adapted to function as a channel to receive the sticks of Writing material for which the pencil is intended to be used. It will be understood that these sticks may be of commonly used writing lead or may be of any other writing material, and for the purpose of conciseness the sticks will bel referred to as sticks of lead hereinafter. The tip I5 is provided at its forward end with a plurality of slits ES which form a corresponding number of fingers 23. The ngers are made to act as spring fingers which grip-'a lead in the channel I8 between them so as to hold the lead firmly at the writing point of the pencil.

The tip I5 has a tubular portion 2l which extends inwardly into the pencil on the axial center of the pencil and is concentric with the tubular element I 2. The internal cavity in the tubular portion 2I constitutes a part of the channel I8 for sticks of lead as is apparent from an inspection of the drawing. The tubular portion 2|v is provided with a helical slot 22 therein, and this slot like the slot I4 in the element I2, is adapted tojconstitute a track for lead propeller elements hereinafter to be described. It will be noted that the helical slots I4 and I2 are of `opposite hand;

looking from the rear end of the pencil, the slot I4 is left-handed and the slot 22 is right-handed.

A cylindrical element 23 is rotatably disposed" Within the sleeve I3. The element 23 V has aportion 24 protruding from the sleeve I3` and casing I0, and this portion is adapted to be used for rotating the element 23 with respect to the casing Il of the pencil for causing additional lead to be protruded from the tip of the pencil as will be hereinafter more fully described. The element 23 is provided with an inwardly tapering portion 25 and a tubular portion 26, connected together as shown. The element 23 forms a magazine 2'I for sticks of lead, and the tapering portion 25 forms the bottom of the magazine. The inner cavity in the tubular portion 25 forms a part of the channel I8 for sticks of lead which, as is apparent from an inspection of the drawing, extends from the magazine 21 to the pencil tip I5. It will be noted that the tubular element I2 has an inwardly chamfered rear end 23, and the tapering portion 25 abuts against and is rotatably disposed in this end of the tubular element The rear end of the element I2 thus forms a bearing for the rotatable element 23 and prevents `movement thereof forwardly of the pencil. The tubular portion 23 is tapered on its forward end and the tubular slotted portion 2| is inwardly chamfered on its rear end, and the tubular portions 2B and 2| t together as at 29. The magazine element 23 is rotatable while the tubular portion 2I is stationary with respect to the casing I2, so it is necessary to provide this 'break in the lead channel at 29; however, the beveled ends of the tubular portions 25. and 2i at 29 function to keep the tubular portions 2t? and 2|, and thus the parts of the lead channel I3 formed thereby, coaxially disposed with respect to each other.

A cap 33 carrying a rubber eraser 3,! therein is disposed in the rear end of the manually rotatable tubular element 23. The tubular element 23 is provided with stops 32 on its inner surface withv which the cap 3B is adapted to abut. The cap is frietionally held in the element 23, but may be removed therefrom when desired, and the cap maybe reversed and again put into the element 23 so that the rubber eraser protrudes from the rear end of the element 23 and may be med for erasing. The stops 32 prevent the cap element 30 from moving any farther forwardly in the magazine 2'1 than in the position in which the cap is shown, whether the cap is in its position in which it is shown or is in reversed position for erasing.

Acylindrical element 33 is disposed within the slotted tubular element I2 and is eccentrically disposed with respect to the element I2 as shown. The element 33 is made up of two

parts

34 and 35 whichv are spaced from each other by

slots

36 and 31 extending longitnidinally of the pencil and by slots'38 and 39 at the ends of the slots 36 and 3i' and extending transversely of the pencil. The slots are all in communication with each other so as to provide a track in the element 33 which extends forwardly of the element 33 V(in the slot 3'!) thence transversely of the element 33 for 180 degrees (in the slot 39), thence rearwardly of the element 33 (in the slot 36) and thence transversely of the element 33 for 180 degrees (in the slot 38). The element 33 is fixed with respect to the manually rotatable element 23 'so as to be rotatable therewith. The part 35 is fixed to the element 23 at the rear end of the part by any suitable means as by welding as at 4E, and the other part 34 is fixed with respect to the rotatable element 23 by means of a longitudinally extending bridging element 4I and a washer-like element 42.v The element 4I is welded to the rear end of the part 35 as at 43 to fix the element 4I to the part 35 and to the rotatable element 23. Both the element 4I and the part 34 at their for- 'Ward ends extend through the washer-like element 42, and the elements 4I and 42 are welded together at 44, and the element 42 and part 34 are welded together at 45. The

parts

34 and 35 being separated by the

Slots

36, 31, 38 and 39, have no direct connection between them; however, the bridging element 4I and the washer-like element 42 connect the two parte together so the parts together form the element 33 which is rotatable with the manually rotatable element 23. t will be noted that for the major part of its length, the bridging element 4I is in contact with the inner surface of the slotted element I2 and is spaced from the element 33, for purposes which will hereinafter be described.

The pencil includes two

lead propeller elements

46 and 41, and each propeller element comprises a pin 48 and a semi-cylindrical part 49. It will be noted that the pin extends through the cylindrical part and extends both inside and outside of the part, and the pin is xed within the cylindrical part by any suitable means as by welding. The propeller elements rit on the eccentrically disposed cylindrical element 33, and the pins 48 move in the

slots

36, 31, 38 and 39 of the cylindrical element which form a track in the element as above described. The pins 48 are also adapted to t in and move in the slots I4 and 22 of the cylindrical element I2 and cylindrical portion 2l which are xed with respect to the casing i3 of the pencil. As will be noted by reference to the drawing, the lead propeller element 41 in its illustrated position in the slot 36 has its pin 48 also in the slot i4, and the other propeller element 46 which is shown in the slot 31 has its pin 48 also in the slot 23 of the centrally disposed tubular portion 2i, and the latter pin extends into the central cavity of the tubular portion 2I which f orms part of the channel i9 for the lead. As the

propeller elements

46 and 41 move within the slot 3l as will be hereinafter described, the ends of their pins 48 contact the inner surface of the bridging element 4 I, and this element is provided with a cam portion 5U which is adapted to contact the ends of the pins as the corresponding propeller elements move in the transversely extending slot 39.

A spring 5I is provided within the part 35 of the eccentrically disposed propeller carrier 33. The spring has a portion 52 extending through a slot 53 in the part 35 (see Fig. 6) and a tang portion 54 extending through a slot 55 provided in the tubular portion 26. The spring is attached to the part 35 by any suitable means such as rivets 56 (see Fig. l). The cylindrical parts 49 of the propeller elements 41 are adapted to make contact with and move over the spring portion 52 and press the tang portion 54 of the spring through the slot 55 in the tubular portion '23 for contacting and gripping a, lead within the tubular portion 2t and preventing the lead from drop ping forwardly in the lead channel within the tubular portion. The spring 5I is preferably provided with a chamfered portion 51 at its forward edge so that the cylindrical parts 49 may readily come into position to press the tang 54 against a lead in the channel I8 in the tubular portion 26, as will be hereinafter more fully described. A guide 58 is disposed about the part 35 and is fixed thereto as by welding at 59. The guide is adapted to receive the cylindrical parts 49 of the

lead propeller elements

46 and 41 when the latter are in position to act on the spring, and the guide acts to hold the cylindrical parts 49 in contact with 6, the tubular part 33 and in position to press n' the spring 5I.

In the operation of the illustrated embodiment of the invention, element 23 by means of its end portion 24 protruding from the casing II) is rotated in the clockwise direction, as seen in Figs. 3 to 5, to cause leads to be fed from the tip I5 of the pencil. It is intended that the pencil shall be held in a vertical or in an approximately vertical position, as gravity is relied on to cause the leads to feed forwardly of the pencil from the magazine 21; such a vertical position for the pencil is of course the natural position for holding a pencil. It is also intended that leads only of the same standard size be used, as will be described. Let it be assumed that the propeller element 41 is in a position forwardly of its position in which it is shown in the drawing so that its pin 48 is at the point 44a in the slot I4 in the tubular element IZ. The propeller element 46 is then in a :position rearwardly of its position in which it is shown so that its pin 48 is at the point 22a in the slot 22 in the tubular portion 2i. As will be readily understood by reference to the drawing, the pin 43 of the propeller element 41 which is in the slot of the outer tubular element I2 is in inoperative position with respect to lead in the channel I8, as it does not extend into the channel. The pin 48 of the propeller element 46 on the other hand extends through the helical slot 22 in the tubular portion 2| and into the lead channel i8, and this propeller element is thus in operative position in which it is adapted to pro-pel a stick of lead within the channel I8. The helical slot i4 in the outer tubular element I2 thus constitutes an inoperative track for the propeller elements 43 and 41, and the slot 22 in the tubular portion 2l constitutes an operative track for the propeller elements.

Assuming then that the

propeller elements

46 and 41 are in their changed positions with the pins 46 of the elements being respectively at the points 22a and la in the operative and inoperative tracks, a rotation of the element 23, and of the element 33 attached thereto in the clockwise direction as seen in Figs. 3 to 5 will cause a corresponding rotation of the

propeller elements

46 and 41. The motion is transmitted to the propeller elements through the cylindrical element 33 by means of the edges of the

slots

35 and 31 through which the pins 43 of the propeller elements 4l" and 46 respectively extend. The pin 48 of the propeller element 41 due to this rotation of this element travels in the slot I4 rearwardly of the point Elia in the slot, the propeller element 41 as a whole has this rearward movement moving over the propeller carrier element 33 with the pin 48 also moving in the slot 36. The pin 48 of the propeller element 46 moves in the forward direction through the slot 22 from the point 22a in the slot, and the propeller element as a whole has this movement moving over the propeller carrier element 33 with its pin 48 moving also in the slot 31. The pin of the propeller element 41 is out of the channel I3 for the leads but the pin of the propeller element 46 is in the channel and abuts the end 39 of a stick of lead 6I in the channel. The lead is thus moved toward the tip 2@ of the pencil by movement of the propeller element 46, and the lead actually extending from the tip i5 is moved out of the tip so as to present a greater length of lead at the end of the tip for writing purposes. This movement in opposite directions of the

propeller elements

45 and 41 is due to the fact that the helical'v slots I4 and 222 are of opposite hand, as

will be observed from the drawing. The helical' slo'tsfurthermore are coextensive and have the same number of turns so that a rotation of the element 23A gives the saine movement along the length of the pencil to both the propeller elements'46 and 41.

After three turns of the rotatable element 23, the propeller element f? is in the position in which it is illustrated with the pin 48 of the element 4l having moved from the point Illa in the slot I4 three turns rearwar ly in the slot to the end I4'b thereof and to the rear end of the slot 36' which is in communication with the transverse slot 38 in the cylindrical element 33. The propeller element 45 is moved by such 'rotation off the element 23 three turns forwardly in the slot 22 to its illustrated position in which its pin 4Bisra't the end 217 of the slot 22 and inwhich the pin is at the forward end of the slot Si that is in communication with the transverse slot in the element 33. Such movement of pro peller element 46 of course causes a corresponding expulsion of lead from the tip i5, as will be understood.

After the propeller elements 4l and 43 have reached their illustrated positions, a further one-half turn of the manually rotatable element 23 will move the propeller element el inwardly to bring its pin 48 into the helical slot 22 at the end 22o thereof (see Fig. 5) and will move the propeller element 4G outwardly to bring its pin 48 into the helical slot i4 at the end 4c thereof (see Fig. 3). Due to the fact that the propeller element 41 in its illustrated position is at the within the guide while the pin 48 of the propeller Since the-- element 33 is eccentrically located with respect element 41 is moving in the slot 38.

to the center of the pencil, this rotation of the element causes the propeller element to move toward the center of the pencil until the'pin 43 of the propeller element enters the helical slot 22 and the lead channel i8. The propeller element 4? cannot rotate again until its pin 4S is completely out of the slot I4 and the element 33^has made a complete half turn to bring the slot 31 into position so that the pin 48 of the propeller element 4'! can enter the slot. The propeller element 41 is then in position to begin its travel forwardly of the pencil to propel a lead in the channel. A gap between the rear end 62 of a lead 63 and the forward end 34 of another lead B5 in the channel is automatically provided by the action of the spring 5I to allow the pin- 48 of the propeller element 4! to enter the channel, as will be hereinafter described.

This half turn of the element 33 effective for moving the pin 43 of the propeller element 4l in to the lead channel I8 is also effective to move the pin 48 of the propeller element 43 into the slot I4 at its end I4c and out of the lead channel with a corresponding outward movement of the propeller element 46 as a whole. The pin 0f the element 46 travels in the transverse slot 39 "of the element 33, and its semi-cylindrical 8 part' 491' moves; over the surface of the element' 33f similar' 'to the manner of movement of the propeller element -475 so' as to move the propeller element 46 outwardly. The cam 50 contacts the end of vthefpin 48 of the propeller element 46 andY 'functions tohold the4 propeller element in contact with the 'outer surface of the element 33.

The` propeller element 4T is now disposed inwardly -of its illustrated position with its pin 48' inthe slot 22; and theV propeller element 46 is-outwardly disposed of' its illustrated position withl its'pinlllinY the'slot' I4. Further rotation of the rotatable element 23 will cause the propeller element 4T tofmoveforwardly of the pen-A cil with its pin 48 being disposed inthe slots 22 and"3, andthepropeller` element will abut the end-IBZ-of'thestick of lead-763i and will move the lead' forwardly in the pencil sol that a further length' oflead-willbey propelled fromthe tip I5. This same Arotation ofth'e' rotatable element 23 will'fcause the' propeller element46 to have' a correspondingmovement rearwardly of the pencilY with its-pin-48'being inthe slots 3G and I4. The

propeller element:- 4175 will eventually reach the' position that: propeller element 4S occupies in thedrawing, and the'- propeller element 46 will eventually reaohtheposition that propeller elementi 41 occupiesiin' thefdrawing., and further movement of'therotatable element 231will cause the' propeller elements.I each to take the same pathbackto its illustratd-position-thatthe other propeller element-*hasrjust been described as taking.. It willthus be-apparentthat each propeller element.. moves' forwardly of the pencil in the slot 22. propelling thef'lead inV the channel I8,

then movesA outwardly'.l into the slot I4, then moves rearwardlyfofthe pencil in the slot I4 andithen moves iinwardly again into the slot 22 and channel.-I8.'. The twopropeller elements 46 and 4f? fare attopposite ends of the cycle; that is,

one-f of. thewpropeller elements is moving into therflead'channelf I8 while-the other is moving outf'of it, and :one propeller element'is moving rearwardlyxof the'pencil while the other propellerelementis movingi forwardly of the pencil.

As hasbeen mentioned, the spring 5I operates to provide a gap between two consecutive leads atthe point .wherefthe'propeller elements 45 and 4? enter the-lead channel i3', in order that the propellerelementsmay enter lthe channel withoutinterference. The, pencil is normally held verticallyor substantially so, andv this is relied on to cause theleads .-to feedy forwardly of the pencil and to causea lead between the points in theflead channel I8.- at which the propeller elements enter andleave the lead channel, such asthelead 63,..to stay in contact with the pin 48 l.of-the.foremost Apropeller element, which is thepropeller element 4S .inthe illustration, as long as thepropelleriv element is in the channel, and to inovinto .contact .with the stick of lead immediatelyahea.which is 'the lead GI in the illustratio'mwhn the propeller element moves out' of theleadph'annel 'and into the slot I4 of. the outertubularV element I2. The spring EI'bpeiates specifically to clamp a lead and hold it from further` forwardlmovement in the lead channel 'I8` when one'of the propeller elements is 'completing its'rearward 'movement and as it moves again intd` the lead channel. The propellerelement. 14T,`A for example, just before it reaches its illustrated position has its semi-- cylindrical part '43 'enter the `guide 58 and co'ntact the chamfereded'l of the spring' 5I. F'rthermovement' rearwardly of the' 'propeller' element causes the spring to be sprung to bring its tang portion 54 into contact with the lead which is beneath the tang portion. In the drawing, this lead is the lead t5. As the propeller element moves still farther rearwardly, it continues to bear on the spring to hold the lead 65 from further forward movement, as will be apparent. During this time, the other propeller element 4B at the forward end of the pencil continues to move and thereby allows the lead G3 to move forwardly of the pencil, and when the propeller elements have reached their illustrated positions, there is a substantial gap between the leads 65 and t3 so that the propeller element 4l has no interference in entering the lead channel I8.

It will be understood that the spring 5| operates in the same manner for both of the propeller elements to provide this gap, and that although the movement of the propeller elements has been described as continuous, actually the manually rotatable element 23 is given only small movements at a time just sunicient to propel a 'sufflcient length of lead from the tip I5 to provide a writing point. When one propeller element moves into the lead channel I 3 and the other propeller element moves out, there is some lost motion of the rotatable element 23 which does not cause a corresponding increase in the writing length of lead at the tip I5; however', the rotatable element 23 isv simply continued tube turned until the lead is again propelled from the tip I5 and a sufficient length of writing point is obtained. It is contemplated that lead of a standard length, such as the illustrated length of the lead S3 in relation to the other parts-of the pencil, only be used with the pencil in order that the spring 5i will function to provide the proper gap between leads at the pointwhere the propeller elements enter the channel I8. It will be noted that the portion 52 of the spring is acted on by the semi-cylindrical portions 49 while the propeller elements 45 and 4l travel inthe transverse slot 38, and the spring thus is operative as the pins 48 actually move into the helical l2 and I3 within the plastic casing Ill. The parts 23, 4|, and 35 are assembled and welded together (without the parts 42 and 34), and the propeller element 4l is put into its illustrated position at the end i4?) of the slot I4. The assembly of the parts-23, 4i, and 35 is then put into the casing Ii) from the rear to bring these parts into their illustrated positions with the tapered portion 25 contact with the chamfered end 23 of the tubular. element l2. The propeller element 4S is then put within the casing with the end of its pin 4B in contact with the bridging element 4E, and the part 34 is then put into the casing iii from the front end of the casing into its proper place. The washer 42 isthen put over the :forward ends of the parts 4i and 34 and in contact with the forward end of. .the tubular element i2, and the parts 4| and 34' are welded to the washer at 44 and 45 respectively. 'Ihe tip te together with the tubular portion 2| are then ready to be putinto place, but the propeller element 4% is first moved rearwardlyo the pencil a distance equal to a few turns or the slot 22 in the tubular portion 2|. The tubular por- Thev pencil is f y assembled by rst casting the tubular elements tion 2| is then inserted into the pencil through the central opening in the end of the part 34 and when the sleeve-like portion I6 is substantially abutting the washer 42, the tip I5 and tubular portion 2| are moved inwardly, so as to bring the pin 48 of the propeller element 4B into the slot 22. The tip I5 is then screwed onto the threaded portion I1 of the tubular element |2, and this rotation of the tip and the tubular portion 2| causes the propeller element 46 to move in the slot 22 and into its illustrated positioni The thread II is made right handed for this purpose, namely, to bring the propeller element 48 forwardly as the tip is threaded on the tubular element I2. It will be understood that the propeller element 46 is moved back into the pencil just far enough prior to its being engaged in the slot 22 and prior to the rotation of the tip I5 in threading it into place so that this rota.- tion is 4just enough to bring the propeller element into its illustrated position. The pencil is now completely assembled, and lead may be inserted into the magazine 21, and the element 23 may be rotated to feed the lead through the pencil.

My improved pencil advantageously provides positive propulsion of leads through the pencil by means of the propeller elements which engage the 'sticks of lead at their ends. The pencil comprises two of the propeller elements one of which is operative while the other is inoperative so that f an excessive manual movement is not required in order to cause propulsion of consecutive sticks of lead through the pencil. The pencil furthermore includes a compact mechanical arrangement comprising the two `opposite handed slots I4 and 22 and the eccentrically disposed propeller carrier element 33 for moving the two propeller elements in opposite directions in the pencil and for moving the propeller elements into and out of their operative and inoperative tracks.

I wish it to be understood that I do not intend vto limit my invention to the specific constructions and arrangements shown and described except only insofar as the claims may be so limited, as it will be apparent to those skilled in the art that changes may be made without departing from the invention. In particular, I wish it to be understood that I do not intend to limit the invention to helical members (I2 and 2|) for propelling the sticks of lead, unless the claims are so limited.

I claim:

l. In a mechanical pencil, the combination of means defining a channel for sticks oi writing material, a pair of propeller elements for abutting sticks of writing material in said channel at the ends of the sticks for propelling the sticks through the channel, and manually operated means i'or moving each of said propeller elements through said channel for a predetermined distance and then out of the channel and then back said predetermined distance and again into the channel into its starting position, said two propeller elements being so operated with respect to each other that one of them is moving in one direction and is in said channel to propel a stick of writing material therein while the other propeller element is moving in the opposite direction and is out of the channel.

2. In a mechanical pencil, the combination of a tubular element defining a channel for sticks of writing material, a propeller element for abutting sticks of writing material in said channel at the ends of the sticks for propelling the sticks through the channel, said tubular element having a helical slot therein deiining a track for said propeller element, a tubular element concentric with said first named tubular element and having a helical slot therein also dening a track for said propeller element, manually operated means for causing said propeller element to move in said tracks, the track in said rst named tubular element causing movement of said propeller velement while the propeller element is in said channel to propel a stick or writing materialin the channel and the track in the other tubular element causing movement of the propeller elementv in the opposite direction while the propeller element is out of the channel, and means for moving said propeller element from one of said tracks to the other after it has travelled a predetermined distance in said one track.

' 3. In a mechanical pencil, the combination oi means dening a channel for sticks of writing material, a pair of propelling elementsA for abutting sticks of Writing material in said ychannel at ,the ends of the sticks for propelling the sticks through the channel, and manually operated means for moving said propeller elements, one

Vof said propeller elements While in position for abutting a stick of writing material in said channel being given a movement in one direction to propel the stick through the channel and the other propeller element being given a movement in the opposite direction while out of position for propelling a stick of writing material in said channel by an operation of said manual means.

4. VIn a mechanical pencil, the combination of means deiining a channel for sticks of Writing i material, a pair of propeller elements for abutting sticks of writing material in said channel lat the ends of the sticks for propelling the sticks through the channel, means defining a track for one of said propeller elements in which the propeller element is .out of position for propelling a stick of writing material in said channel, means defining a track for the other of said propeller elements in which the propeller element is in position to propel la stick of writing material in said channel, and manually operated means for moving said propeller elements, the propeller element in said first named track being given a movement for propelling a stick of Writing material through said channel and the propeller element in the other track being given a movement in the opposite direction by an operation of said manual means.

5. In a mechanical pencil, the combination of means defining a channel for sticks of writing material, a pair of propeller elements for abutting sticks of Writing material in said channel at the ends of the sticks for propelling the sticks through the channel, means defining operative and inoperative tracks for said propeller elements in which the propeller elements are respectively in position for propelling a stick of writing material in said channel or are out of position for propelling sticks of writing material in said channel, one of said propeller elements being in an operative track while the other propeller element "f is in an inoperative track, manually operated means for moving said propeller elements, the propeller element in an operative track being given a movement to propel a stick of Writing material and the other propeller element being given a movement in the opposite direction by an operation of said manual means, and means .for moving one of said propeller elements from `Aan operative track to an inoperative track and for moving the other propeller element from an fri:

ill

inoperative track to an operative track by an operation of said manual means after the propeller elements have travelled predetermined distances in the tracks in which they were originally.

6. In a mechanical pencil, the combination of means defining a channel for sticks of writing material, a pair of propeller elements for abutting Sticks of Writing material in said channel at the ends of the sticks for propelling the sticks through the channel, helical elements defining operative and inoperative tracks for said propeller elements in which the propeller elements are respectively in position for propelling a stick of Writing material in said channel or are out oi' Vposition for propelling sticks of writing material in said channel, one of said propeller elements being in an operative track While the other propeller element is in an inoperative track, `rotatable means adapted to be operated manually for moving said propeller elements, the propeller element in an operative track being given a movement to propel a stick of writing lmaterial and vthe other propeller clement being given a movement in the opposite direction by an operation of said manual means, and means for moving one of said propeller elements from an operative track to an inoperative track and for moving the other propeller element from an inoperative track to an operative track by an operation of said manual means after the propeller elements have travelled predetermined distances in the tracks in which they were originally.

7. In a. mechanical pencil, the combination of means defining a channel for sticks of Writing material, a pair of propeller elements for abutA` ting sticks of `Writing material in said channel at the ends of the sticks for propelling the sticks through the channel, means defining an operative track in which both of said propeller elements may travel and in which the propeller elements are in position for propelling a stick of Writing material in said channel, means dening an inoperative track in which both of said propeller elements may travel and in which the propeller elements are out of position for propelling a stick of Writing material in said channel, one of said propeller elements being adapted to be in one of said tracks While the other pro- `peller element is in the other track, manually operated means for moving said propeller elements, the propeller element in the operative track being given a movement to propel a stick of writing and the other propeller element being given va movement in the opposite direction by an operation of said manual means, and means Vfor moving the propeller element in said operative track to'saidinoperative track and for moving the propeller element in said inoperative track to said operative track by an operation of said manual means after the propeller elements have travelled predetermined distances in the tracks in which they were originally.

8. In a mechanical pencil, the combination of means defining a channel for sticks of writing material, a pair of propeller elements for abutting sticks of writing material in said channel at the ends of the sticks for propelling the sticks through the channel, a Vhelical element defining an operative helical track in which both of said propeller elements may travel and in which the propeller elements are in position for propelling sticks of Writing material in said channel. a helical element defining an inoperative helical track in which both of said propeller elements may travel and in which the propeller elements are lout of position for propelling sticks of writing in the opposite direction by an operation of said manual means, and means for moving the propeller element in said operative track to said inoperative track and for moving the propeller element in said inoperative track to saidoperative track by an operation of said manual means after the propeller elements have travelled predetermined distances in the tracks in which they "were originally.

9. In a mechanical pencil, the combination oi means defining a channel for sticks of writing material, a pair of propeller elements for abutting sticks of writing material in said channel at the ends of the sticks for propelling the sticks through vthe channel, said first named means deiining an operative track in which both of said propeller elements may travel and in which the propeller elements are in position for propelling sticks of writing material in said channel, means deiining an inoperative track in which both of said propeller elements may travel and in which the `propeller elements are out of position for propelling sticks of writing material in said channel, one of said propeller elements being adapted 'to be in one of said tracks While the other propeller element is in the other track, manually operated means for moving said propeller elements, the propeller element in the operative track being given a movement to propel a stick of writing material and the other propeller element being given a movement in the opposite ydirection by an operation of said manual means,

and means for moving the propeller element in said operative track to said inoperative track and for moving the propeller element in said inopera-A tive track to said operative track by an operation of said manual means after the propeller ele-q ments have travelled predetermined distances in the tracks in which they were originally.

10. In a mechanical pencil, the combination of a central tubular element defining a channel for -sticks of writing material, a pair of propeller elements for abutting sticks of writing material in said channel at the ends of the sticks for propelling the sticks through the channel, said tubular element having a slot` therein and thereby forining an operative track in which both of said propeller elements may travel and in which the propeller elements are in position for propelling sticks of writing material in said channel, a tubular element concentric with said rst named tubular element and having a slot therein to form an inoperative track for both of said propeller elements and in which the propeller elements are out of position for propelling sticks of writing material in said channel, one of said propeller elements being adapted to be in one of said tracks while the other propeller element is in the other track, manually operated means for moving said propeller elements, the propeller element in the operative track being given a movement to propel `a stick of writing material and the other propeller element being given a movementin the opposite direction by an operation of said manual llo means, and means for moving the propeller ele'- ment in said operative track to said inoperative track and for moving the propeller element in said inoperative track to said operative track by an operation of said manual means after the propeller elements have travelled predetermined distances in the tracks in which they were originally.

ll. In a mechanical pencil, the combination of a central tubular element defininga channel for sticks of writing material, a pair of propeller elements for abutting sticks of Writing material in said channel at the ends of the sticks :for propelling the sticks through the channel, said tubular element having a helical slot therein and thereby forming an operative track in which both of said propeller elements may travel and in which the propeller elements are in position for propelling sticks of Writing material in said channel, a tubular element concentric with said first named tubular element and having a helical slot therein to thereby form an inoperative track for both of said propeller elements and in which the propeller elements are out o1" position for propelling sticks of writing material in said channel, one 0i said propeller elements being adapted to be in one of said tracks while the other propeller element is in the other track, manually rotatable means for giving relative rotation to said propeller elements with respect to said tubular elements l whereby the propeller elements travel in the slots of the tubular elements, the propeller element in the operative track being givenI a movement to propel a stick oi Writing material and the other propeller element being given a movement in the opposite direction by a rotative movement of the manual means, and means for moving the propeller element in said operative track to said inoperative track and for moving the propeller element in said inoperative track to said operative track by a rotative movement of the manual means after the propeller elements have travelled predetermined distances in the tracks in which they were originally.

12. In a mechanical pencil, the combination of a central tubular element defining a channel for sticks of writing material, a pair of propeller elements for abutting sticks of writing material in said channel at the ends of the sticks for pro'- pelling the sticks through the channel, a tubular element concentric with said rst named tubular element and spaced radially thereform, said propeller elements being disposed between said tubular elements, said inner and outer tubular elements respectively deining operative and inoperative tracks for said propeller elements in which the propeller elements are respectively in position for propelling sticks of writing material in said channel or are out of position for propelling sticks of writing material in said channel, one of said propeller elements being in an operative track while the other propeller element is in an inoperative track, means disposed between said concentric tubular elements and adapted to have relative movement with respect thereto and acting on said propeller elements to move the same in said tracks, the propeller element in an operative track being given a movement to propela stick of writing material and the other propeller element being given a movement in the opposite direction by a movement of said last named means relative to the tubular elements.

13. In a mechanical pencil, the combination of a central tubular element deiining a channel for Vsticks of writing material, a pairof propeller eleatoom? `l ments fior abutting sticks of writingmaterial in -said channel at the ends of the sticks yfor propel-ling tL e sticks through the chan elysa-id tubular element having a slot therein and thereby forming an ,operative ,track in which both of said propeller elements may travel Aand in which the propeller elements are in position for propelling sticks ci writing material in said channel, a `tubular element concentric with said rst named tubular element and having a slot therein to thereby form an inoperative track for both of -said propeller elements in which the propeller elements are out o position for propelling sticks of writing material in sait. channel, one of said propeller elements being adapted to be in one of said tracks While other propeller element is in the other track, manuali 4 movable means acting on A'said propeller eleme ,-s to move the same Vand disposed betr-.icon said tubular elements, the pro- ;peller element in the operative track being given a movement to propel stick of writing material and the other propeller element being given a movement in the opposite direction by a movement of said manual means, and means for moving the propeller element in said operative track to said linoperative track and for moving the pro peller element in said inoperative track to said operative track by a movement of said manual means after the propeller elements have travelled predetermined distances in the tracks in ..vhich they were originally.

14.Y In a mechanical pencil, the combination of a central tubular element defining a channel for sticks of Writing material, a pair of propeller elements for abutting sticks of writing material in said channel at the ends of the sticks for propelling the sticks through the channel, said tubular element having a helical slot therein and thereby forming an operative track in which both of said propeller elements may travel and in which the propeller elements are in position for propelling sticks of Writing material in said channel, a tubular element concentric with said iirst named tubular element and having a helical slot therein to thereby form an inoperative track in which both of said propeller elements may travel and in which the propeller elements are ont of position for propelling sticks of writing material in said channel, one of said propeller elements being adapted to be in one of said tracks while the other propeller element is in the other track, a rotatable `carrier element for said propeller elements disposed between said tubular elements and adapted to give relative movement to said propeller elements with respect to said tubular elements whereby the propeller elements travel in said helical slots, the propeller element in the operative track being given a movement bythe track to propel a stick of Writing material in said channel and the other propeller element being given a movement in the opposite direction by the other track on a movement of the manual means, and means for moving the propeller element in said operative track to said inoperative track and for moving the propeller element in said inoperative track to said operative track by a movement of said carrier element after the propeller elements have travelled predetermined distances in the tracks in which they were originally.

15. In a mechanical pencil, the combination of an inner tubular element defining a channel for sticks of Writing material, a pair of propeller elements for abutting sticks o f Writing material in said channel at the ends of the sticks for propelling the sticks through the channel. an; outer tubular element concentric with said'rst'named tubular element and spaced radially therefrom, said inner and outer tubular elements respectively deming operative and inoperative tracks for said propeller' elements in which the propeller elements are respectively in position for propelling sticks of Writing material in said channel or are out of position for propelling sticks of writing material in said channel, one of said propeller elements being in an operative track whilerthe other propeller element is in an inoperative track, a tubular element disposed between said above named tubular elements and eccentrically with respect thereto whereby to have portions thereof adjacent both said inner and outer tubular elements, said eccentrically disposed tubular element being adapted to have movement relative to the other tubular elements and acting on said propeller elements to move the same in said tracks, the propeller element in an operative track being given a movement to propel a stick of writing material in said channel and the other propeller element being given a movement in the opposite direction by a movement of said eccentrically disposed tubular element relative to the other tubular ele-ments, said eccentrically disposed tubular element on a rotation thereof relative to said inst named tubular elements being adapted to move one of the propeller elements in an operative track to an inoperative track and to move the other propeller element from an .inoperative track to an operative track after the propeller elements have travelled predetermined distances in the tracks in which they were originally.

lo. In a mechanical pencil, the combination of an inner tubular element dem'ng a channel for sticks of writing material, a pair of propeller elements for abutting sticks of writing material in said channel at the ends of the sticks for propelling the sticks through the channel, said tubular element having a helical slot therein and thereby forming an operative track in which both of said propeller elements may travel and in which the propeller elements are in position for propelling sticks of writing material in said channel, an outer tubular element concentric with said rst named tubular element and having a helical slot therein to thereby form an inoperative track in which both of said propeller elements may travel and in which the propeller elements are out of position for propelling sticks of writing material in said channel, one of said propeller elements being adapted to be in one of said tracks While the other propeller element is in the other track, and a tubular carrier element for said propeller elements disposed between said inner and outer tubular elements and being eccentrically disposed with respect to said last named tubular elements whereby to have portions adjacent both inner and outer tubular elements, said carrier element being adapted to be manually rotated and moving said propeller elements in said slots while allowing movement of the propeller elements longitudinally of the pencil so that the propeller' element in said operative track is moved to propel sticks of writing material in said channel and the other propeller element is moved in the opposite direction when the carrier element is rotated, said carrier element when rotated and when the propeller elements are at the ends of the tracks in which they are disposed functioning to move the propeller element in the operative track to the inoperative track and the propeller element in the inoperative track to the operative track,

17. In a mechanical pencil, the combination of an inner tubular element dening a channel for sticks of Writing material, a pair of propeller elements for abutting sticks of writing material at the ends of the sticks for propelling the sticks through the channel, said tubular element having a helical slot therein and thereby forming an operative track in which both of said propeller I elements may travel and in Which the propeller elements are in position for propelling sticks of writing material in said channel, a tubular element concentric with said rst named tubular element and having a helical slot therein to Y thereby form an inoperative track in which both of said propeller elements may travel and in which the propeller elements are out of position for propelling sticks of writing material in said channel, one of said propeller elements being adapted to be in one of said tracks While the other propeller element is in the other track, and a tubular carrier element for said propeller elements disposed between said first named tubular elements and being eccentrically disposed with respect to the tubular elements, said carrier element having two opposite slots therein extending longitudinally thereof for receiving said propeller elements With the slots being so disposed that a propeller element in one of the slots is in said operative track and a propeller element in the other slot is in said inoperative track whereby the carrier element When rotated moves said propeller element in said operative track to propel a stick of writing material in said channel and moves the propeller element in the other track in the opposite direction, said carrier element having spaced transverse slots corresponding to ends of said helical slots and adapted to receive said propeller1 elements and connecting the longitudinal slots in the carrier element at opposite ends of these longitudinal slots whereby the carrier element When rotated and when the propeller elements have travelled to opposite ends of the longitudinal slots in the carrier element Will move the propeller element in said operative track to the inoperative track and will move the other propeller element from said inoperative track to said operative track.

18. In a method for propelling sticks of Writing material in a pencil which feed through a channel for the sticks, the steps which comprise, moving a propeller element in the channel for a predetermined distance to propel a stick of writing material therein, moving the propeller element out of the channel and back said predetermined distance, and then moving the propeller element again into said channel into its starting position at which it may act on another stick of writing material, and moving another propeller element in the same manner as the rst named propeller element, each of said propeller elements being moved in said channel to propel a stick of writing material therein while the other propeller element is moved in the opposite direction without the channel.

19. In a method for propelling sticks of writing material in a pencil which feed from a magazine and thence through a channel, the steps which comprise, moving a propeller element abutting a stick of Writing material in the channel for a predetermined distance in the channel to propel the stick of Writing material,

moving the propeller element out of the channel and back said predetermined distance, and then moving the propeller element again into said channel into its starting position at which it may act on another stick of writing material, moving another propeller element in the same manner as the rst named propeller element, each of said propeller elements having the same starting position and being moved in said channel to propel a stick of writing material therein While the other propeller element is moved in the opposite direction witho-ut the channel, and clutching a stick of writing material feeding from said magazine in said channel at a point between the magazine and the starting position of the propeller elements just as each propeller element is reaching its starting position in its return movement for causing a spacing between adjacent sticks of writing material at the starting position of the propeller elements to allow the propeller element to enter the channel at the starting position.

KEITH T. BLEUER.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date T. M. 201,911 Aug. 11, 1925 1,764,156 Douglas June 17, 1930 1,967,484 Stenersen July 24, 1934