US1849210A - Mechanical pencil - Google Patents

Description

March 15, 1932. J. w. WELSH 1,849,210

MECHANI CAL PENCIL Filed March 21, 1929 2 Sheets-Sheet 1 was; 2 i: A :1 5: 20 "F n 7/ I i 8 z 3% 55 WI A/ 2 g d 4 .A ii: 24 I E1? 3 H 7/3 5/ 5 51 58 24 \.i j 43 March 15, 1932. J, w. WELSH MECHANICAL PENCIL Filed March 21, 1929 2 Sheets-Sheet 2 [mm 2101" Jaw/rues W Wetsh Patented Mar. 15, 1932 UNITED STATES PATENT OFFICE JAMES WILSON WELSH, OF PROVIDENCE, RHODE ISLAND, ASSIGNOB TO THE WELSH MANUFACTURING GOMPANY, OF PROVIDENCE, RHODE ISLAND, A CORPORATION OF RHODE ISLAND MECHANICAL PENCIL Application filed March 21, 1929.. serial No. 348,839,

The present invention relates to marking devices, and more particularly to mechanlcal pencils.

An object of the invention is to improve.

upon devices of the above-described character, to the end that their efliciency may be 1ncreased, their construction simplified and their cost of manufacture reduced. Other and further objects will be explained hereinafter and will be particularly pointed out in the appended claims. I

In the accompanying drawings, illustrating a preferred embodiment of the present invention, Fig. l is an elevation; Flg. 2 1s a central longitudinal section taken through the casing and the cap, substantially upon the line 22 of Fig. 1, looking in the direction of the arrows; Fig. 3 .is a section, upon a larger scale, taken upon the line 33 of 93 Fig. 2, looking in the direction of the arrows; Fig. 4 is a fragmentary, enlarged view of the body of the pencil, with the casing removed, the parts being shown in positions similar to those of Fig. 2; Figs. 5 and 6 are,

* sections taken substantially upon the lines 5-5 and 66 of Fig. 4, looking in the directions of the arrows; Figs. 7 and 8 are views, upon difierent scales, of details; Fig. 9 is a View of a further detail; and Fig. 10 is a 39 view of a modification.

The pencil-carrying body is housed in a casing 2 (Figs. 1, 2 and 3). The pencil may be retained in the owners pocket by a clip 6 having a terminal prong 8 and an intermediately disposed prong 9 (Figs. 2 and 9) extending through openings 10 and bent over against the inner wall 12 of the casing. The clip 6 is shown in Fig. 9 before assembly with the casing2. In such condition, the prongs are shown extending medially of the sides 11 and 13 of the cli 6 at right angles to the body of the clip, t e prong 9 being cut out of the body of the clip. Where metal casings 2 are used, the o ening's 10 are previously formed in the casing, but when celluloid or other suitable non-metallic casings 2 are employed, the prongs may drive their own openings into the casing.

The lead or other marker 14 projects from the forward, conical end of the casing and is gradually fed forward, as it is used up, by rotary feed mechanism hereinafter to be described. An eraser 16 at the other or rear end of the pencil is ordinarily protected against dirt and thelike by a'cap 18, but may be put intoservice when the cap is removed.

The lead 14 is frictionally clutched or held by a plunger tube 20 through one end 22 of which it projects, as will be understood more particularly from Figs. 2, 3 and 4. The tube 20 is slidably mounted in a slotted tube 24. The lower end 26 of the slotted tube 24 may rest in a guide groove 28 at the lower end of the casing, as will be understood from Fig. 2. The guide groove 28 may, however, be formed in a separate metal piece 29 that is screwed into the lower end of the casing 2 at 31, particularly ifthe casing 2 is of celluloid or other non-metallic material. The lower end 22 of the marker-holding tube 20 is normally within *the slotted tube 24, as shown in Figs. 2 and 3, but may be projected through the lower end 26 of the slotted tube 24, as shown in Fig. 4, towards the end of its feed movement through the slotted tube 24, as hereinafter described. This happens, of course, when th lead 14 has become nearly completely used up, and the-small, still-remaining, portion of the lead is then forced out of the end 22 of the clutch tube 20 by a marker plunger or push rod 32 that is slidably mounted in the clutch tube 20. Normally, as will be described hereinafter, the marker-holding or clutch tube 20 and the plunger push rod 32 movelongitudinally through the slotted tube 24 as a unit, but at their lower limit of movement, the clutch tube 20 is held stationary and the push rod 32 is advanced therethrough, into the position illustrated in Fig. 4, to expel the lead. Upon a reverse movement of the parts, on the other hand, the push rod 32 first withdraws into the clutch tube 20, to permit the insertion of a new lead into. the same, and then the clutch tube 20, the lead held thereby and the plunger push rod 32 may be withdrawn into the slotted tube 24 in readiness for a new advance of the lead '14. It is thus possible to have as much lead projecting from the casing as desired, and if the lead should, by

any chance, be advanced too far out of the I casing, all that is necessar is to retract the push rod 32 and the hol 'ng tube as a.

unit, carrying the lead with it,'until just so much lead only projects from the casing as is desired. The lead may similarly be withdrawn into the casing to protect it against breakage when the pencil is not in use. The plunger push rod 32 may be advanced throughthe end 22 of the holding tube 20 up to the very end 22 of the tube, so that practically the very last tip of the lead 14 may be used up, for the tube 20 will continue to clutch the lead 14 even though only a ver small portion of it is left.

The tube 20 is intermediately provided, near its u per end, with a projection 33., A portion 0 tion 33 is slotted longitudinally at for a considerable distance to permit free sliding movement between the walls of the slot of a projection 34 that is provided upon the push rod 32. The purpose of the slot 42 in the slotted tube 24is to receive the projections 33 and 34 and keep them alined in the slot 42, thereby permitting free slidable movement through the sloted tube 24 of the plunger tube 20 and the plunger push rod 32.. A preferred method of manufacturing the tube 20 is to die a suitably shaped blank out of sheet steel, and then to fold it, as shown. The upper end 54 of the tube 20 is closed to fprevent the projection 34 from riding out o the slot 40. A

The preferred mechanism for advancing and retracting the plunger-holding tube 20 and the plunger push rod 32 will now be\described. The projections 33 and 34 of the tube 20 and the push rod 32,- respectively, are adapted to be engaged b a'helical or spiral thread 36 upon a rotata le sleeve 38 that is mounted to enclose the slotted tube 24. As

will be explained hereinafter, the spirallythreaded sleeve 38, though rotatable relative to the slotted tube 24, is held against longitudinal movementrelative to the slotted tube 24. The sleeve 38 may be made in any desired manner, as by spirally coiling a stamped-out, flat, sheet-metal blank. As i1- lustrated in Figs. 2 and 3, the projections 33 and-34 normally engage spaced portions of the spiralthread 36., so that theprojections 33 and 34 will normally remain separated from each other by a constant distance, As the sleeve 38 is rotated about the slotted tube 24, therefore, the holding tube 20' and the push rod 32 will be advanced or retracted through the slotted tube 24 as 'a unit, according to the direction of rotation of the sleeve 38. The

projections 33 and 34' will slide freely through the slot 42 during such rotationof the spirally threaded sleeve 38. To advance or retract thelead 14, therefore, all that is necessary is to rotate the spiral sleeve 38, holding the slotted tube 24 stationary.

the tube 20 just above the projec- 2 guano According to the preferred construction the spiral sleeve 38 is ada ted to be rotated by securing it to a manua y rotatable tube 46 that projects through the casing at the rear or eraser end of the encil. This may be effected in any desired way, preferably by inserting the upper end 44 of the tube 38 in the lower end 45 of the tube 46, and soldering or swedging the partstogether. To bring this about, of course, the diameters of the parts 44 and 45 should preferably be such that the former will just fit into the latter. As the cap 18 is fitted frictionally on the upper enlarged or expanded end 47 of the tube 46, the lead 14 may be advanced or retracted at will by rotating the cap 18 in one direction or the other, while holding the slotted tube 24 against rotation. The purpose of enlargin the tube 46 at 47 is two fold: first, the tu e 46 is enabled to fit better in the casing 2, asshown in Fig. 2; and secondly, it provides a seat for the eraser 16. Or, the tube 46 may be of enlarged diameter to start with, and the end 45 of the tube may, in that event, be reduced in diameter. The enlarged portion 47 of the tube 46 is slotted at 49, to provide a resilient 'holding action upon the eraser 16.

It is now necessary to describe how the slotted tube 24 is held against rotation during the rotatable movement of the sleeve 38. After the parts thus far described, with the exception of the cap 18 and the casing 2, are assembled together, they are inserted as a unit in a barrel 51. The barrel 51 is substantially of the same length as the sleeve 58 and pro- 59, permitting the lower end of the spirally threaded sleeve 38 to engage against the end plate 57. The opening 59 is provided with a key lock or other projection 68 to engage against the slot 42 of the slotted tube 24 to prevent the tube 24 from rotating relative to the end plate 57 A collar 61 1S slipped over the lower end 26 of the slotted tube 24 untiPit contacts with the end plate 57, and is secured in place in any desired manner. A very effective securing means consists in merely striking out, or expanding outward, at 63, a 'portion of the wall of the tube 24 just below the collar 61. j I

The parts thus far described, except for the casing 2 and the cap 18, will be held together as a'unit, if the slotted tube 24 is caused to be held in aplace. The upper end of the slotted tube 24 is therefore provided with a The shank 65 is secured in the slotted tube 24 in any desired manner, as by soldering. The head 67 is of greater diameter than the diameter of the slotted tube 24, and is disposed outside of the slotted tube in order that it may engage against the upper end 44 of the sleeve 38. The slotted tube 24 is thus prevented from slipping longitudinally out through the opening 59 and the parts are held together as a unit.

The rivet serves a further purpose in that it acts as a bottom for the tube 46. The tube 46 may then serve as a chamber for extra leads 14. To remove an extra lead 14, all that is necessary is to unseat the eraser 16, thereby affording access to the lead chamber,

To permit inserting this unit into the easing 2, the slot 53 of the barrel 51 1s made wide enough so that the prongs 8 and 9 may readily be passed therethrough. 'Thepurpose of the other slot 55 is to strengthen the spring action of the spring walls 69 and 71 that are formed on both sides of the slots 53 and 55, without causing these spring walls to produce a bulge in the casing 2. It is, therefore, made narrower than the slot 53. The walls 69 and 71 are bent outward to engage frictionally against the inner walls of the casing 2. As the walls 69 and 71 are substantially as long as the sleeve 38, they bind against the inner cylindrical walls of the easing 2 throughout a substantial area above the conical end of the casing. Sufficient spring tension is thus provided 'to hold the unit frictionally in position in the casing durlng the rotation of the sleeve'38, but the unit may readily be withdrawn from the casing, in opposition to the sprin tension of the spring walls 69 and 71, by pul ing outward upon the portion 47 of the tube 46.

In operation, the turning movement of the cap 18 will be communicated to the spirally threaded sleeve 38. The projections 33 and 34 will thus be advanced and retracted according to the direction of rotation. of the cap 18, carrying the lead 14 with them as a unit. At the forward limit of slidable movement of the holding tube 20, the projection 33, being nearer to the end plate than the projection 34, will ride off the open end 58 of the thread 36, and become seatedin a depressed stop 73 that is provided in the end plate 57. As the holding tube '20 can not advance beyond that point, further rotative movement of the sleeve 38 will cause the projection 34 to advance toward, and into engagement with, the stop 33, as shown in Fig. 4, with the result that, as the push rod 32 advances through the holding tube 20, it will expel the lead. A reverse rotatable movement of the sleeve 38 will cause, first, the projection 34,'and then, the projection 33, to engage with the thread 36, after which a new lead may be inserted in the end 22 of the holding-tube 20. i

As an alternative construction, the wall at the lower end of the sleeve 38 may be cut away at a point external to the thread to provide projection, a longitudinally slotted tube within which the plunger is slidably mounted, the longitudinal slot of the tube permitting free' sliding movement of the projection between the walls of the slot, a plug havin ted tube and a head of greater diameter than the diameter of the slotted tube disposed outside of the slotted tube, the head being continuous so as to close the slot of the tube, whereby the head may serve as the closed bottom of a receptacle, a sleeve enclosingthe slotted tube with the head of the plug engaging an end of the sleeve, the sleeve being rotatable relative to the, slotted tube, means cooperating with the head of the plug to hold the sleeve and the slotted tube against relative longitudinal movement, the sleeve having a spiral thread adapted to engage the a shank secured in one end of the slotprojection to advance and retract the plunger according to the direction of relative rotation of the sleeve and the slotted tube, a cas-v ing, and means for holding the slotted tube against rotative movement in the casing, whereby rotative movement of the sleeve in the casing will effect longitudinal movementof the. plunger in the slotted tube.

2. A device of the class describd having, in

combination, a marker plunger having a projection, a longitudinally slotted tube within which the plunger is. slidably mounted, the longitudinal slot of the tube permitting free sliding movement of the projection between the walls of the slot, a plug having a shank secured in one end of the slotted tube and a head of greater diameter than the diameter of the slotted tube disposed outside of the slotted tube, a sleeve enclosing the slottedtube with the head of the plug engaging an end of the sleeve, the sleeve being rotatable relative to the slotted tube, means cooperating with the head of the plug to hold the sleeve and the slotted tube against relative longitudinal movement, the sleeve having a spiral thread adapted to engage the projection to advance and retract the plunger according to the direction of relative rotation of the sleeve and the slotted tube, a chamber tube, the end of the sleeve near the plug being secured in an end of the chamber tube, whereby the head of the plug forms a closed bottom for the chamber tube, and a casing in which the slotted tube is held againstrotative movement, with the other end of the chamber tube projecting through an end of the casing, whereby roplunger in the slotted tube.

3. In a device of the class described having a marker plunger, a casing, a clip, and means extending through the inner walls of the casing for holding the ch on the cas1ng, means for advancing an retracting the plunger in the casing including a barrel having two longitudinal slots, whereby spring walls are formed between the slots, one of the slots being wide enough'to permit the extending means to be passed theret-hrough when the barrel is slid into the casing, and the other slot being narrower than the said one slot, whereby the spring walls are made relatively wide so that they are adapted to engage frictionally against the inner walls of the casing with suflicient spring tension to hold the plunger frictionally in pesition 1n the casing, but without spring tension great enough to produce a bulge in the casing.

4. As an article of manufacture, a barrel having two longitudinal slots,wherebyspr1ng walls are formed between the slots, one of the slots being wide enough to permit an article of substantial width to be passed therethrough, the other slot being narrower than the said one slot, whereby the spring walls,

, whereby spring walls are formed'between are made relatively wide, the barrel having an end late bent over at an angle to the axis of the arrel, and the end plate be ng provided with an opening.

5. As an article of manufacture, a sheet metal barrel having two longitudinal slots,

the slots, the barrel having an end plate bent over at an angle to the axis of the barrel, and

the end plate being provided with an opening, a slotted marker-plunger-holding tube extending through the opening and an elevated sto the late having means for preventing rotiition 0 1 the slotted marker-plunger-holding tube. I

6. A device of the class described havlng, in combination, a marker plunger having a projection, a longitudinally slotted tube within which the plunger is slidably mounted, the longitudinal slot of the tube permitting tree sliding movement of the projection between the walls of the slot, a plug having a shank secured in one end of the slotted tube and a head of greater diameter than the diameter of the slotted tube disposed outside ,of the slotted tube, a sleeve enclosing the slotted tube with the head of the plug engaging an end of the sleeve, the sleeve being rotatable relative to the slotted tube and having a spiral thread adapted to engage the projection to advance andretract the plunger according to the direction of relative rotation of the sleeve and the slotted tube, a barrel in WhlCh theslotted tube in engagement with the end plate,

sleeve is rotatably disposed, the barrel having an end plate provided with an opening through which the slotted tube extends, means engaging the end plate and cooperating with the head of the rivet to hold the sleeve and the slotted tube against relative longitudinal movement, whereby rotative movement of the sleeve relatively to'the barrel will effect longitudinal movement of the plunger in the slotted tube, and means for slot-ted tube anda head of greater diameter than the diameter of the slotted tube disposed outside of the slotted tube, a sleeve enclosing the slotted tube with the head of the plug engaging an end of the sleeve, the sleeve being rotatable relative to the slotted tube and having a spiral thread spaced portions of'which are adapted to engage the alined projections to advance and retract the holding tube and the plunger therein according to the direction of relative rotation of the sleeve and the slotted tube, a barrel in which the sleeve is rotatably disposed, the barrel having an end plate engaging the other'end of the sleeve and provided with an opening through which the slotted tube extends, a collar upon the means upon the slotted tube engaging the collar and cooperating with the head of the rivet to hold the sleeve and the slot-ted tube against relative longitudinal movement, whereby rotative movement of the sleeve relatively to the barrel will efiect longitudinal movement of the plunger and the holding tube in the slotted tube, and means for holding the slotted tube from rotation with respect to the barrel.

8. A devlce. of the class described having, in combination, a marker plunger having a projection, alongitudinally slotted tube within which the plunger is slidably mounted and having a projection near one end, the longi tudinal 'slot of the slotted tube permitting free sliding movement of the marker-plunger through adapted to engage the marker-plunger projection to advance and retract the plunger according to the direction of relative rotation of the sleeve and the slotted tube, a barrel which the sleeve is rotatably disposed, a'casing, means disposed near the other end of the slotted tube and cooperating with the slotted-tube projection to hold the plunger, the slotted tube, the sleeve and the arrel together as a unit against relative longitudinal movement but permitting relative rotative movement between the sleeve and the slotted tube, and means for effecting rotative movement of the sleeve relative to the slotted tube in the casing to produce longitudinal movement of the plunger in the slotted tube. 9. A device of the class described having, in combination, a marker plunger having a projection, a longitudinally slotted tube within which the plunger is slidably mounted and havinga projection near one end, the longitudinal slotof the slotted tube permitting free sliding movement of the marker plunger projection between the walls of the slot, a sleeve enclosing the slotted tube, the sleeve being rotatable relative to the slotted tube but being held against longitudinal movement relative to the slotted tube, the

.sleeve having a spiral thread extending therethrough adapted to engage the projection to advance and retract the plunger according to the direction of relative rotation of the sleeve and the slotted tube, a chamber tube. one end of the sleeve being secured in an end of the chamber tube. a barrel in which the sleeve is rotatably disposed, a casing, and means disposed near the other end of the slotted tube and cooperating with the slottedtube projection to hold the plunger, the tubes, the sleeve and the barrel together as a unit against relative longitudinal movement but permitting relative rotative movement between the sleeve and the slotted tube, and the other end of the chamber tube projecting through one end of the casing, whereby rotative movement of the chamber tube in the casing will effect a rotative movement of the sleeve relatively to the slotted tube and thereby efiect longitudinal movement of the plunger in the slotted tube.

10. A device of the class described having,

' in combination. a marker plunger havin a projection. a longitudinally slotted tube within which the plunger is slidably mounted. the longitudinal slot of the slotted tube permitting free sliding movement of the projection between the walls of the slot, a sleeve enclosing the. slotted tube, the sleeve having a spiral thread adapted to engage the projection to advance and retract the plunger according to the direction of relative rotation of the sleeve and the slotted tube. a barrel in which the sleeve is rotatably disposed. the barrel having an end plate provided with an opening through which the slotted tube extends, m'eans for efiecting rotative movement of the sleeve relatively to the barrel to effect longitudinal movement of the pioneer in the slotted tube, two means respectively provided near opposite ends of the slotted tube and respectively on aging the end late and the opposite end of the sleeve for hol ding the parts. together as a unit against relative longitudinal movement but permitting relative rotative'movement between the sleeve and the slotted tube, and a casing, the unit being adapted to be inserted in the casing.

In testimony whereof, I have hereunto subscribed my name.

JAMES WILSON WELSH!

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