US2911948A

US2911948A - Mechanical pencil with an automatic feed mechanism

Info

Publication number: US2911948A
Application number: US618467A
Authority: US
Inventors: Spector Baruch
Original assignee: NOVERA H SPECTOR
Current assignee: NOVERA H SPECTOR
Priority date: 1956-10-26
Filing date: 1956-10-26
Publication date: 1959-11-10
Anticipated expiration: 1976-11-10

Description

B. SPECTOR Nov. 10, 1959 MECHANICAL PENCIL WITH AN AUTOMATIC FEED MECHANISM Filed Oct. 26, 1956 2 Sheets-Sheet l NOV. 10, 1959 B, SPECTOR 2,911,948

MECHANICAL PENCIL WITH AN AUTOMATIC FEED MECHANISM Filed oct.y 2e, 195e z sheets-sheet 2 FIG. I4.

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BAR ucH sPEcToR 2041 ATTQRNEY.'

United States Patent O MECHANICAL PENCIL WITH AN AUTOMATIC FEED MECHANISM Baruch Spector, Massapequa Park, N.Y., assiguor of onehalf to Novera H. Spector, Merrick, N.Y.

Application October 26, 1956, Serial No. 618,467

i 3 Claims. (Cl. 1Z0-14.1)

This invention relates to a mechanical pencil with an automatic feed mechanism.

The princip-al object of this invention is the provision of a mechanical pencil embodying an automatic pressure feed mechanism which automatically feeds the lead (writing element) under the pressure which is normally exerted upon the pencil when it is used in conventional manner.

The writing element (herein designated as the lead) is encased in the present device in a sleeve which supports it and prevents it from breaking during the writing operation. This sleeve is adapted to move longitudinally relative to the pencil holder, that is, the main casing in which the lead and the mechanism are mounted and which is held in the hand when writing. It is this relative movement between the sleeve and the main casing first in one direction and then in the opposite direction which provides the force necessary to feed the lead in the present device. When the pencil is held in the hand and is used in conventional manner on a writing surface, the lower end of the sleeve is brought to bear against said Writing surface while pressure is applied to the outer casing in downward direction. As the lead is consumed in writing, the sleeve retracts into the outer casing, or stated more precisely, the outer casing descends relative to the sleeve. When the pressure is released, that is, when the pencil is lifted from the writing surface, spring means return the sleeve to its forwardly projected position, this time beyond the lead since a portion of the lead has now been consumed. Further pressure upon the outer casing when writing is resumed will advance the lead to writing position and as it is consumed the sleeve will rise. This process is continued until the lead is fully consumed.

Another important object of the invention is the provision of a mechanism as above described with the additional feature of an automatic refill mechanism which replaces the used or consumed leads with new ones. This rell mechanism includes a magazine which contains a plurality of replacement leads and spring means for urging them seriatim into the sleeve above mentioned.

The principles above mentioned may be applied in the several forms of the invention shown in the drawing. But in addition to the various mechanisms which may be employed in carrying out these principles, there is the important feature that said principles and said mechanisms may be applied to leads of various conventional and unconventional shapes. For example, two conventional shapes which are illustrated in the drawing are the cylindrical and rectangular shapes commonly used. But in addition, there is the provision in the present invention of cylindrical and rectangular shapes which are provided with ne ribs extending longitudinally of the lead. These fine ribs are adapted to be compressed by the sleeve which holds the lead and they thereby provide a press iit which holds the lead securely in the sleeve while permitting it to advance as it is consumed.

It is therefore not only the object of this invention to ice provide a pencil which is adapted to utilize ribbed lead of the character described, but it is also an object of the invention to provide ribbed lead of this character for the purpose above set forth and adapted for use in said pencil as well as in other mechanical pencils known to-the art.

The invention is illustrated in the accompanying drawing in which:

Fig. 1 is a side view, partly broken away and in section, showing a mechanical pencil made in accordance with one form of this invention.

Fig. 2 is a longitudinal section therethrough on the line 2 2 of Fig. 1.

Fig. 3 is a transverse section on the line 3-3 of Fig. 2, showing the casing in open position.

Fig. 4 is a similar view on the line 4-4 of Fig. 2. t

Fig. 5 is another transverse section on the line 5-5 of Fig. 2. v

Fig. 6 is a side view of one of the elements shown in Fig. 1.

Fig. 7 is a transverse section through a conventional rectangular stick of lead which may be used in the pencil illustrated in Figs. 1 to 6 inclusive.

Fig. 7A is a transverse section through a rectangular stick of lead provided with longitudinally extending ribs.

Fig. 8 is a longitudinal section through a mechanical pencil made in accordance with a second form of this invention.

Fig. 9 is a forward end view of said pencil looking in the direction of

arrows

9, 9 in Fig. 8.

Fig. 10 is a top end view looking in the direction of

arrows

10, 10 in Fig. 8.

Fig. l1 is a fragmentary view of the upper end of the outer casing of the pencil shown in Fig.

Fig. 12 is a fragmentary view of one of the elements of the pencil shown in Fig. 8.

Fig. 13 is a transverse section through a cylindrical stick of lead adapted for use in the pencil shown in Figs. 8 to 12 inclusive.

Fig. 13A is a transverse section on the line 13A-13A of Fig. 13B, and showing a longitudinally ribbed cylindrical stick of lead adapted for use in the pencil shown in Figs. 8 to 12.

Fig. 13B is a side view of said ribbed stick of lead.

Fig. 14 is a longitudinal section through va refill-type of mechanical pencil made in accordance with a third form of this invention. v

Fig. 15 is a transverse section on the line 15-15 of Fig. 14.

Fig. 16 is a fragmentary section showing a modification `of the magazine and refill mechanism of Figs. 14 and 15.

Fig. 17 is a transverse section on the line 17-17 of Fig. 16.

Fig. 18 is a longitudinal section through another pencil made in accordance with still another form of this im vention.

Fig. 19 is a transverse section on the line 19-19 of of Fig. 18.

Referring now to the first form of this invention and Figs. 1 to 6 of the drawing, it will be observed that a casing 10 is provided which consists of two sides 12 and 14 which are pivotally connected to each other by means of a hinge pin or pintle 16 which extends substantially the full length of the -two casing side members 12 and 14. Each side element 12 and 14 is a three-sided member of dove-tail shape in cross-section or end view.' Clip portions 18 and 20 on the two side members are engage'- able with each other to hold Ithe casing closed as Figs. 1 and 2 clearly show.

Mounted within the two casing side members 12 `and 14 are

guide bars

22 and 24. These guide bars have tapered or converging sides so as to dove-tail intothe casing side members 12 and 14. It will be observed in Fig. l that these guide bars are spaced from each other when the casing is closed so as to provide a channel 26 between themextending longitudinally of the casing. The major portion of the twoV guide bars .is disposed within the casing and occupying approximately two-thirds of its length, leaving the upper third of the casing vacant. Projecting downwardly from the casing and from the main body of the two

guide bars

22 and 24 are tapered portions of said guide bars designated in the drawing as 28 and 30 respectively. The lower ends ofthese tapered portions are rounded olf as the drawing clearly shows in Fig. 1 to provide a smooth bearing surface for application to the paper on which the pencil is to be used.

Occupying channel 26 is a pair of spacer bars 32 and 34 respectively which are best shown in Fig. 2, one of said bars, 34, being Valso shown in Fig. 6. These spacer bars 32 and 34 are substantially the same length as the guide bars 22 and 24. Like the guide bars, spacer bars 32 and 34 are provided at their lower ends with tapered

portions

36 and 38 which are rounded olf to provide a suitable bearing surface for the writing paper. It will be observed in Fig. 2 that a channel 40 separates the two

vspacer bars

36 and 38 and it will now be seen that the writing element or lead 42 occupies said channel 40. Consequently, the lead is held in place against lateral displacement by the two

guide bars

22 and 24 and the two

spacer bars

32 and 34.

In this form of the invention, the channel which is provided between guide bars 22 and 24 on the one hand and between spacer bars 32 and 34 on the other hand, is rectangular in cross-section. It is designed to receive the rectangular lead 42 whose cross-sectional shape is shown in Fig. 7. To assist in preventing the lead from slipping longitudinally out of its channel, a leaf spring 44 is provided in the tapered end portion 28 of guide bar 22. This spring tensionally and frictionally engages the lead and holds it against accidental longitudinal displacement in downward direction. This shape of lead is conventional and consequently 'some external gripping means, such as the spring last mentioned, is required to prevent such accidental displacement.

`But Fig. 7A discloses a lead 46 which requires no such external gripping means to hold it in place. This stick of lead is also rectangular in cross-sectional -shape but it is provided with fine longitudinally extending ribs 48 which project outwardly therefrom, preferably along its four corners. These line ribs serve as spacers and bearing surfaces between the lead and the corners of the channel in which the lead is disposed. When the lead is inserted into said channel, these tine ribs are squeezed or compressed between the corners of the channel and the corners of the lead and a press-tit is thereby provided. In this connection, it will be understood that there is relatively little clearance between the side walls of the lead and the side walls of the channel. The height of thene ribs is therefore necessarily limited and it exceeds only slightly the extent of clearance or tolerance between the lead and the walls of the channel. These ribs also compensate for variations in tolerance between the walls of the lead and channel.

Occupying the same channel as the lead is a pusher bar 50 whose lower end abuts the upper end of the lead. This pusher bar performs two functions: It prevents upward dislodgment of the lead while it is being used and also provides the means of bearing down on the lead during the writing operation, and it also is involved in the operation by which the lead is advanced in the pencil as it is consumed. Two

clutch members

60 and 62 engage the pusher bar 50. The upper clutch 60 may be designated the holding clutch and the lower clutch 62 may be designated the feed clutch. The upper holding clutch 60 projects outwardly through an opening 64 in the casing. Opposite said opening 64 is a rod 66 which extends between and bears against the two

clutches

60 and 62. The lower feed clutch 62 is contained entirely within the casing and one end designated 62a engages a fulcrum 68 provided in a cutout 70 in which said lower feed clutch 62 is disposed. A torsion spring 72 engages said lower feed clutch and urges it to swing in counterclockwise direction about said fulcrum 68 as viewed in Fig. 2. This has the effect of urging rod 66 upwardly and to cause the upper holding clutch 60 to swing in counter-clockwise direction, also as viewed in Fig. '2.

When the pencil is held upon a sheet of paper in conventional manner, it is the casing 10 which is held in the hand and pressed downwardly. The curved lower ends of the tapered

portions

28 and 30, and 36 and 38 bear against the paper and oppose the downward pressure exerted upon the casing. The upper end or edge 74 defined by opening 64 serves as a shoulder engaging the outwardly projecting end of the upper holding clutch 60 and the downward pressure exerted on and through the casing tends to assist the rod 66 in swinging said clutch in counter-clockwise direction. The effect of such action upon the holding clutch 60 is to cause it to grip the pusher bar 50 as is clearly shown in Fig. 2. Consequently, any downward pressure upon the casing during the writing operation is transmitted through the upper holding clutch 60 to the pusher bar 50 and through said pusher bar to the lead itself.

It has above been stated that the rounded ends of tapered

portions

28, 30, 36 and 38 bear against the paper during the writing operation. As the lead is consumed, it is automatically advanced by the pressure exerted through the casing and upper holding clutch 60 and pusher bar 50. Consequently, relative movement must take place betweensaid casing, holding clutch and pusher bar on the one hand and the

tapered portions

28, 30, 36 and 38 on the other hand. What happens is that these tapered portions remain stationary since they bear against the writing surface and the other elements, namely, the casing, holding clutch 60 and pusher bar 5t), descend in direct proportion tothe wear upon the lead.

It will now be observed that a shoulder 76 is provided at the upper ends of tapered

portions

36 and 38 of the spacer bars and that said shoulder is engageable with a ange 78 formed at the lower end of each casing member. Abutment of the shoulder against the ange limits the relative movement between the spacer bars and the casing in one direction but permits relative movement in the opposite direction. At this point it may be stated that the spacer bars 32 and 34 are secured to the guide bars 22 and 24 by any conventional means so that all four bars move integrally with each other and constitute a sleeve for the lead. When the lead is consumed during writing, the casing, upper holding clutch 60 and pusher bar 50 descend so as to space the flanges 78 from the shoulders 76. This downward movement of the casing, holding clutch and pusher bar takes place against the action of compression spring 80 whose upper end abuts said holding clutch and whose lower end rests upon a plate 82 which is connected to the guide and spacer bar assembly last mentioned and designated as the sleeve for the lead. The fulcrum 68 above mentioned is shown to be formed at the lower end of said plate 82. A pin 84 is secured to the upper end of said plate 82 and it extends through an opening 86 in the upper holding clutch 60. This pin serves no other function than to support the compression spring 80 and to hold it in place between said upper holding clutch and said plate 82.

When the pencil is lifted from the writing surface, spring 80 is free to move the upper clutch member 60, and casing 10 upwardly while moving the guide and spacer bar assembly downwardly so as to re-engage the shoulders 76 with the flanges 78. The pusher bar 50 does not move with the casing and upper holding clutch ,but rather remains fixed to the guide and spacer bar assembly by reason of the action of the feed clutch 62 thereon. Torsion spring 72 causes the feed clutch 62 to engage the pusher bar 50. This is shown in Fig. 2. Since said torsion spring and feed clutch are supported by the guide and spacer bar assembly and not by the casing 10, they will hold the pusher bar fixed in position relative to said guide and spacer bar assembly. The action of compression spring 80 on the upper holding clutch 60 causes said clutch to swing in clockwise direction as viewed in Fig. 2 and consequently releases it from the pusher bar 50. Hence, while the pusher bar is held by the lower feed clutch 62, the upper holding clutch 60 and the casing are moved upwardly relative to said pusher bar. A hook-shaped portion 88 at the top of the pusher bar limits such relative movement between it and the upper holding clutch 60.

This process continues automatically and without the attention or conscious participation of the person using the pencil. As the lead is consumed during the writing operation the casing and pusher bar descend while the guide and spacer bar assembly remain stationary. Once the pencil is lifted from the paper, the casing moves upwardly relative to said assembly while the pushser bar remains in its advanced position. When it is desired to replace the lead, the casing may be opened and the pusher bar pulled upwardly by means of its hook portion 88. To free it for such movement, the right-hand end of the upper holding clutch 60 is pressed downwardly against the rod 66, causing said rod to press downwardly on the right-hand end of the lower feed clutch 62. This causes the two clutches to swing in counter-clockwise direction and to disengage the pusher bar. A new stick of lead is inserted through the bottom end of channel 50 and the pusher bar is then moved downwardly into abutment with it. The clutch members are released and they once again engage the pusher bar preparatory to the operations above described. A stop member 90 secured to the casing 10 below the right-hand end of upper holding clutch 60 limits the downward movement of said clutch.

From the foregoing it will be understood that the lead cannot be seen when the pencil is held against the Writing surface. lt is enclosed on all sides by the tapered

portions

28, 30, 36 and 38 of the guide and spacer bar assembly. The spacer bars and their

tapered portions

36 and 38 are made of the same thickness as the lead and said

tapered portions

36 and 38 are preferably colored black or any other color which would contrast with the color of tapered

portions

23 and 30, so as to mark the precise location of the lead. 1t is by following

tapered portions

36 and 38 that the person using the pencil may properly and precisely position and align the lead relative to the writing surface.

Turning now to the second form of this invention and to Figs. 8 to l2 inclusive, it will be observed that the pencil 100 shown therein involves the same principle as the pencil iirst above described except that it utilizes a cylindrical lead 102 instead of a rectangular lead 42. Pencil 100 is provided with a casing 104 which may be hexagonal in shape as shown in Figs. 9 and l() but this is purely illustrative. lt is simply a tube which may be made in any desired cross-sectional shape. Screwed to the lower end of casing 104 is a tapered or conical nose 106 through which a tubular sleeve 108 extends. The tapered nose 106 helps position the sleeve 108 and support it during the writing operation. The lower end of sleeve 10S is rounded oft to provide a smooth bearing surface relative to the writing surface but it is not as sharply rounded as the lower ends of tapered

portions

26, 28, 36 and 38 above described. Sleeve 108 is adapted to receive the lead 102 and a pusher bar 110 which projects downwardly into the sleeve and into abutment with said lead.

Before feeding of the lead begins, the upper end of pusher bar 110 abuts a cup-shaped member 112 which occupies the upper end of casing 104. Cup-shaped member 112 is provided with a detent 114 which engages a bayonet slot 116 in casing 104. It is by this means that the cup-shaped member 112 may be held in place in the top of said casing to close ofi the top of the casing and for a further purpose. This purpose is to support a second cup-shaped member 118 in which is mounted an eraser 120. Cup-shaped member 118 is provided with an embossment 122 which engages a bayonet slot 124 in the cup member 112 so as to hold the cup member 118 in place in the cup member 112. It will now be observed that a rod 126 is mounted within the casing 104, its upper end projecting through an opening 128 in cup member 112 and abutting the cup member 118.

Rod 126 performs substantially the same function as rod 66 in the iirst form of this invention. There is a reduced portion 130 at the lower end of rod 126, providing a shoulder 132 between said reduced portion and the main body of said rod. The reduced portion 130 projects through an opening in upper holding clutch 134 and the lower end of said reduced portion abuts a lower feed clutch 136. Shoulder 132 abuts the clutch 134. A bearing 138 is connected to a cup-shaped member 140 and it supports said lower reduced end 130 of rod 126 while permitting longitudinal movement of said rod. A compression spring 142 is mounted between clutch 134 and bearing 138 and it tends to urge the clutch 134 in clockwise direction as viewed in Fig. 8. The right-hand end of said clutch 134 projects into an opening 144 in the casing 104 and edge 146 defining the upper end of said opening serves as a fulcrum for said clutch member 134. It is this action which causes clutch 134 to engage the pusher rod 110, especially when the pencil is held to a writing surface and the person using the pencil bears down upon the casing 104. This is precisely the same action as has above been described in connection with the first form of this invention.

It will now be understood that sleeve 108 is fixed to the cup member 140 which, as above indicated, is secured to the bearing 138. Consequently, an assembly consisting of sleeve 108, cup 140 and bearing 138 is provided and this assembly will hereinafter be designated the sleeve assembly, corresponding to the guide and spacer bar assembly first above described. As the lead is consumed during a writing operation, the casing 104, together with its tapered nose 106, its upper holding clutch 134 and the pusher rod 110 will descend in direct proportion to consumption of the lead.

When the pencil is lifted from the writing surface, spring 142' will push said casing 104, the clutch 134 and the tapered nose 106 upwardly relative to the sleeve 108, the cup 140 and the bearing 138. It will now be noted that a second compression spring engages one end of clutch 136 while the opposite end projects through an opening 152 in cup 140 and bears against the edge 154 which functions as a fulcrum. This clutch 136 tends to lock the pusher rod 110 in place relative to the sleeve 108 when the other spring 142 causes the casing 104, the clutch 134 and tapered nose 106 to move upwardly relative to said sleeve 108. This is precisely the same action as has above been described in connection with the iirst form of this invention.

When it is desired to release the two clutches from the push rod 110, cup-shaped member 118 with its eraser 120 are turned and by means of bayonet slot 116, rod 126 is depressed.

Cylindrical lead 102 shown in Fig. 13 is conventional in shape. In Fig. 13A is shown a similarly shaped lead 156 which is provided with a plurality of very fine longitudinally extending ribs 158. Three such ribs are shownl in the drawing but it will be understood that this number is purely illustrative. These ribs 158 perform the same function as ribs 48 above described. They are pressed between the main body of the lead and the cylindrical wall of sleeve 10S. A press-lit is thereby provided between the lead and the sleeve which securely holds the lead in place except when it is advanced by the mechanism above described. The ribs (or fins) are shaved, compressed or crushed on the insertion within their tracks.

Although the pencil is shown in a vertical position `in Fig. 8, it is expected that during use the pencil will be tilted to an angle inclined from the vertical, such angle varying with the practices of the individual users of the pencil. This is because the pencil shown in Fig. 8 is intended to function as a writing pencil, as distinguished from a drawing or drafting pencil. The pencil shown in Figs. 1 and 2 is designed as a drafting pencil and is intended to be used in a generally vertical position. The foregoing is not to be construed as limiting the uses of the two pencils but merely indicating the purposes for which they were primarily designed.

A sheet of paper 160 is shown disposed at an angle to the pencil in Fig. 8. This sheet would normally occupy a horizontal plane and the pencil an angular position relative to said plane. But as above indicated, the pencil is shown in vertical position for illustrative purposes only. It will be observed that the lower end of sleeve 108 is cut oif at with only a rounded peripheral edge, as distinguished from the fully rounded ends of the tapered

portions

28, 30, 36 and 38. Since the sleeve 108 is considerably larger in diameter than the lead which it holds, tilting of the pencil relative to the paper, as indicated in Fig. 8, will provide a space below the sleeve into which the lead will project. If the lower end of the sleeve were rounded off entirely as in the case of Figs. 1 and 2, the lead would not project from the sleeve and it would not write.

Referring now to Figs. 14 and 15 and to the third form of this invention, a fully automatic pencil 200 is shown which includes a magazine 202 of leads 204 and means for replacing consumed leads with the leads in the magazine. Speaking generally, pencil 200 corresponds to pencil 100 and includes a casing 206 and a tapered or conical nose 208 secured to the lower end of the casing. Within the casing is a cup-shaped member 210 to which is secured a sleeve 212 which projects through the conical nose 208. The upper end of sleeve 212 is provided with a ared portion 214 to facilitate entry of the lead. A push rod 216 is provided and this rod not only performs the functions of the

push rods

50 and 110 above mentioned but it also has the additional function of pushing a new lead into the sleeve 212 in replacement of a consumed lead. Push rod 216 has a reduced lower end 218 and a reduced upper end 220 with a shoulder 222 at the top of reduced end 218, and a second shoulder 224 at the bottom of reduced end 220. A head 226 is provided at the top of reduced end 226. There are two

clutch members

230 and 232 respectively which correspond to the clutch members of the first two forms of the invention and perform the same functions.

More specifically, clutch member 230 projects through an opening 234 in the casing 206 and it abuts edge 236 which serves as a fulcrum. Compression spring 238 rests upon the cup 210 and bears outwardly against the clutch member 230. The lower clutch member 232 projects through an opening 240 in cup 210 and it engages an edge 242 which serves as a fulcrum. A spring 244 bears upwardly against clutch 232 and downwardly against the magazine 202. Both springs tend to urge the clutches in clockwise direction about their respective fulcrums and both thereby cause the clutches to engage the push rod.

A leaf spring 250 is disposed within the magazine for engagement with the leads therein and the leads are thereby urged radially inwardly, as viewed in Fig. 15, to the center of the casing. The innermost lead would then be in alignment with sleeve 212 and the pusher rod. It is assumed that it is now desired to write until the lowermost lead in sleeve 212 is fully consumed. When this takes place, the reducer lower end 218 projects through the magazine and occupies the position which is now shown to be occupied by the stick of lead 204a. Lead 204b would be fully consumed and lead 204e would then occupy its position at the lower end of sleeve 212. By the same token, lead 204d would occupy the present position of 204C. It is now necessary to retract the push rod 216 from the position which is now shown to be occupied by lead 204a and to return it to the position which it is now shown to occupy in Fig. 14.

In order to do this,

clutches

230 and 232 must be released from the push rod 216. This is done by turning the top cap 260 until the cup-shaped cam member 260 which is secured to the lower end of said cap engages release bar 264 and presses said bar downwardly. This release bar has a shoulder 266 which engages clutch 230 and a shoulder 268 which engages clutch 232. When release bar 264 is depressed, these clutches are caused to swing in counterclockwise direction in order to release the push rod 216. The push rod is now free to be retracted to the position which it is shown to occupy in Fig. 14.

Push rod 216 may be so retracted by simply pulling upwardly upon cap 260. Secured to the inside of cap 260 by means of rivets 270 or any other conventional means is a second cap 272. Secured to said second cap is a rod 274 which projects downwardly through an opening in the cam cup 262 and into casing 206. lt will new be observed that head 226 at the top of push rod 216 is located immediately below rod 274. Said rod 274 thereby serves as a stop member to prevent upward movement of the push rod beyond its present position as shown in Fig. 14. Secured to rod 274 by means of rivet 276 is a hook-shaped member 278 which is engageable with head 226 when the push rod 216 is moved downwardly to the extent of the length of one of the leads. This hookshaped member 278 serves as a stop to limit such downward movement of the push rod but it also serves as a hook for pulling the push rod upwardly to the position which it is presently shown to occupy in Fig. 14. This is done by simply pulling upwardly upon cap 260 since the hook is secured to said cap by means of rod 274 and inner cap 272. rThere is a cross plate 280 with a slot 282 formed therein. This slot is large to accommodate the reduced upper end 220 of the push rod but it is too small to pass either shoulder 224 or head 226 and consequently the cross plate limits the upward movement of the push rod and prevents it from being pulled out of the casing. Once the push rod is retracted to its Fig. 14 position, lead 204g will be pushed into the position which it is now shown to occupy in Fig. 14 by means of spring 250.

In Figs. 16 and 17 is shown a modified version of the magazine shown in Figs. 14 and l5. In Figs. 14 and l5 the magazine holds the several leads in a straight line and its capacity is limited to the radial distance between the center of the casing and spring 250; a pencil of relatively small diameter could accommodate a magazine 202 of only limited capacity. To overcome this limitation, the magazine 300 shown in Figs. 16 and 17 occupies a spiral position, the inner end of the spiral coinciding with the center of the casing and the outer end of the spiral being disposed adjacent the casing wall. This spiral magazine may consist of a single convolution or a part of a single convolution or a plurality of convolutions, and in the latter case its capacity would be extremely large. To urge the leads in spiral magazine 300 toward the inner end thereof, a torsion spring 362 is provided which winds around the push rod 304. The upper end of said torsion spring is secured to a bracket 306 which, in turn, is fastened to the casing 308. The lower end of the torsion spring is coiled as shown at 310 and it then is provided with a lowermost portion 312 which projects downwardly into the magazine and abuts the last stick of lead therein.

Referring now to the nal form of this invention and to Figs. 18 and 19, a pencil 320 is shown to be provided which .is even more fully automatic than that shown in Fig. 14. These two pencils are, essentially, alike, especially in their clutch, push rod and magazine elements.

'l'hey diler mainly in the means for retracting the push rod. This is done manually in Fig. 14 and automatically in Fig. 18.

Clutch members

322 and 324 correspond to

clutch members

230 and 232 shown in Fig. 14. But instead of coil spring 238 bearing up against clutch 230, a leaf spring 326 bears up against clutch 322. Push rod 328 is like push rod 216 eXcept that it is provided with a downwardly facing shoulder 330 in place of upwardly facing shoulder 224 and in place of head 226 there is a hole 332 which is engaged by a tension spring 334. The upper end of said spring is secured to cap 336. There is also a double shoulder 338 between shoulder 330 and hole 332 on the push rod 328 which is not found on push rod 216. The action of spring 334 is to draw push rod 328 upwardly to its Fig. 18 position.

When push rod 328 descends in the normal course of use of the pencil and as the lead is consumed in such use, eventually shoulder 330 will engage the top of release bar 340 and further downward movement of said push rod will cause said release bar by means of its shoulders 342 and 344 to release the two

clutch members

322 and 324 from the push rod. Spring 334 will thereupon pull the push rod upwardly. At the same time, a rocker 3'46 pivoted on 348 and urged inwardly by leaf spring 350 will pivot in clockwise as soon as its lower end 352 clears the release lbar 340. Once this happens, the release bar will be held by said rocker against upward movement and the clutch members will be held in released position long enough to enable the push rod to rise under the inuence of spring 334 to its upper position.

As the push rod 328 thus moves upwardly, double shoulder 338 will engage pin 360 on plate 362. Plate 362 is pivotally mounted on pivot 364 and this upward movement of the push rod will therefore cause the plate 362 to pivot in counterclockwise direction about the pivot 364. It will now be observed that another pin 366 is secured to the free end of plate 362 and said pin is engageable with a cam edge 368 on rocker 346. When this happens, the rocker is caused to swing in counterclockwise direction against leaf spring 350. This returns the rocker to Fig. 18 position, releasing the release bar 340 for upward movement under the action of springs 326 and 370, thereby causing the clutch members to reengage the push rod.

Plate 362 is normally held in horizontal position and the means which accomplishes this will now be described. It consists of a leaf spring 380 which is secured at its outer end to the pencil casing 382, and a pair of

pins

384 and 386 which are secured to plate 362 and engage opposite sides of said leaf spring. Proper positioning of the plate 362 is important since its position determines the moment of release of the release bar 340.

The foregoing is illustrative of preferred forms of this invention and it will be understood that these forms may be modified and other forms may 'be provided within the broad spirit of the invention and the broad scope of the claims.

I claim:

1. A mechanical pencil comprising a holder, a sleeve projecting longitudinally from the lower end of said holder and being mounted for slidable movement relative to said holder longitudinally of itself and of the holder, said sleeve being adapted to receive a writing element slidably mounted therein for longitudinal movement relative to said sleeve, a pusher bar mounted in said holder and projecting downwardly into said sleeve for engagement with a writing element slidably mounted therein, said pusher bar being disposed longitudinally of said holder and said sleeve and being mounted for longitudinal slidable movement relative to said holder and said sleeve, and clutch means mounted in the holder and engaging said pusher bar to permit downward movement of said pusher bar relative to said holder while preventing upward movement of said pusher bar relative to said holder, the holder being provided with additional clutch means mounted therein and engaging said pusher bar, said additional clutch means being connected to the sleeve and being adapted to prevent upward movement of the pusher bar relative to said sleeve while permitting downward movement of the pusher bar relative to the sleeve, a connecting link being provided between the first c-lutch means and the additional clutch means, the rst clutch means being manually releasable from the pusher bar to permit upward movement of the pusher bar relative to the holder, the connecting link being adapted to release the additional clutch means from the pusher bar when the first clutch means is manually released therefrom, thereby permitting upward movement of said pusher bar relative to said sleeve, the lower end of the sleeve being provided with a bearing surface which is adapted to bear against a writing surface when the mechanical pencil is in use, whereby the sleeve is prevented from moving downwardly relative to said writing surface, the holder being adapted to move downwardly relative to said sleeve and said writing surface when the user of said mechanical pencil bears down upon said holder with conventional writing pressure, whereby said writing pressure is transmitted through said holder, said rst clutch means and said pusher bar to the writing element in the sleeve, spring means being provided between the holder and the sleeve to move the holder upwardly relative to the sleeve and relative to the additional clutch means and pusher bar when said holder is relieved of said writing pressure, a magazine being provided in the holder for a plurality of writing elements, a portion of said magazine being disposed across the path of the pusher bar and in alignment therewith and being open at its upper end to permit entry of said pusher bar and being open at its lower end to permit entry of a writing element into said sleeve, and spring means engageable with said writing elements to urge them seriatim into alignment with said pusher bar and said sleeve between the pusher bar and the sleeve.

2. A mechanical pencil in accordance with claim 1, wherein the magazine comprises a narrow chamber extending radially outwardly in a straight line from the center of said holder, said pusher bar and said sleeve being also disposed in the center of said holder.

3. A mechanical pencil in accordance with claim 1, wherein the magazine comprises a narrow chamber extending spirally outwardly from the center of said holder, said pusher bar and said sleeve being also disposed in the center of said holder.

References Cited in the tile of this patent UNITED STATES PATENTS TM 70,598 Automatic, Eagle Pencil Co Sept. 15, 1908 1,447,677 Lindberg Mar. 6, 1923 1,633,529 Holman June 21, 1927 1,729,786 Lindberg Oct. 1, 1929 1,729,814 Becker Oct. 1, 1929 2,011,270 Chesler Aug. 13, 1935 2,107,816 Chesler Feb. 8, 1938 2,469,411 Robbins May 10, 1949 2,492,839 Brubaker Dec. 29, 1949 2,528,328 Baker et al. Oct. 31, 1950 2,646,775 Vierling July 28, 1953 FOREIGN PATENTS 12,383 Great Britain Dec. 21, 1848 358,292 Germany Sept. 8, 1922