US2049965A - Lead pencil - Google Patents

Description

, LEISTENSCHNEIDER Aug. 4, 1936. I

LEAD PENCIL Filed Jan. 29 1934 jlnvencor' Augusf Leisiqerisch'neider y Patented Aug. 4, 1 9 36 UNITED STATES LEAD ritNcn. August Leistenschnelder, Dusseldorf, Germany Application January 29, 1934, Serial No. 708,801

' in Germany January 31, 1933 13 Claims.

The present invention relates to a mechanical or magazine lead pencil, and particularly to one of the type in which the lead is advanced by iongitudinal or axial movement of a cap or operating member accessible at the exterior of the pencil. The invention is, in some respects, a modification of and an improvement upon the pencil construction disclosed in United States Patent No. 1,969,085, granted Aug. '7, 1934, for a joint invention of August Leistenschneider and Konrad Kressel.

An object of the invention isthe provision of a generally improved and more satisfactory pencil of this type.

I Another object isthe' provision, in apencil of this kind, of improved lead gripping or clamping means, and particularly of such means designed so that the lead may be gripped relatively close to the writing point or end thereof, and so that, 20 when the gripping means releasesthe lead, it will release it positively and completely, without binding or dragging on the lead.

To these and other ends the invention resides in certain improvements and combinations of 25 parts, all as will be hereinafter more fully described, the novel features being pointed out in the claims at the end of the specification.

In the accompanying drawing:

Fig. 1 shows a mechanical lead pencil accord- 30 gig to the invention in longitudinal section.

.Fig. 2 shows a magazine for lead pencils according to the invention in longitudinal section. Referring to the drawing, the lead is gripped near the tip of the pencil by a clamping sleeve indicated in general at ll, this sleeve being split longitudinally through part or, preferably, all of its length, to form a plurality of "gripping or clamping fingers. The extreme lower or forward ends of the fingers have exterior surfaces which 40 are of generally conical shape, converging steeply or sharply toward their lower ends, as indicated at i, which surfaces may be described as 'being tapered downwardly, or as growing smaller in a downward or forward direction. Rearward- 4 ly or above the downwardly tapered portion, these 55 or ledge 2. From this step 2 to a point near the (Cl. 120.1'l)

rear ends of the clamping fingers, the exterior surfaces of the fingers may be substantially cylindrical, as shown, and the rear ends of the fingers are loosely hung at the lower end of the lead tube 9, in a manner similar to or identical with the manner in which the fingers i9 and 20 are hung in said Patent No. 1,969,085.

The inner surfaces of the fingers 0, near their forward ends, are of arcuate cross section and of a radius substantially equal to that of the lead intended to be used in thit pencil. Near the middle of the length of the fingers, the inner surfaces of the fingers are conical, inclining or sloping obliquely outwardly and rearwardly, as

shown, and thence the inner surfaces continue .reardly with a cross sectional radius sufficiently large so as not to bear against the lead to any, substantial extent. Hence, when the clamping fingers are moved radially inwardly toward each other, by the clamping ring hereafter described, the fingers will grip a stick of lead extending centrally through the fingers, and this gripping will take'place at and near the lower ends of the fingers but not at the upper ends of the fingers, where the diameter of the internal space through the fingers is greater than that of the lead. The fingers preferably grip the lead throughout an axial extent or length of at least 1.5 times the diameter of the lead.

The clamping ring, for operating the fingers of the clamping sleeve 0 to grip or release the lead, is indicated in general at 4. Intermediate its length, the ring has a shoulder 8, and a substantially cylindrical tubular portion of larger diameter extends rearwardly from this shoulder, terting in an outwardly extending annular flange 6. A coiled spring I, surrounding this part of the clamping ring, pressesrearwardly on the flange 6 and constantly tends to move the clamping ring rearwa-rdly until the upper or rearward surface 8' of the fiange 6 comes into contact with the front surface I of a block or member I secured in fixed position in thepencil casing, and preferably split longitudinally into two parts, for ease of assembly. From the shoulder 8, another tubular portion of the clamping ring, of smaller cross-sectional diameter than the first mentioned portion, extends forwardly to a forward end or edge 3. This last mentioned tubular portion at its forward end has its inner surface conicaliy shaped to be substantially .complemental to and cooperate with the conical outer surfaces of the fingers immediately forwardly of the shoulder 2, as will be readily seen from the drawing. If the clamping ring be moved forwardly relatively. to

the clamping fingers, the ring will force the fingers radially inwardly toward each other to grip an interposed lead. If the ring be moved rearwardly relatively to the fingers, the fingers will be released from the lead, gradually at first,

nose piece or casing ll, preferably of resilientmetal and longitudinally split at its forward end. It will be noted from the drawing that the cavity or chamber within this nose piece H is of sumcient diameter to accommodate the lead clamping parts, almost to the extreme end of the pencil,

clamping ring when the thus enabling the clamping parts to be brought very close to the writing end of the lead. Yet,

with the design here shown, this does not make the exterior of the nose piece of awkward size or shape. The exterior of the nose piece may be of decreasing size in aforward direction, as shown, and may be described as tapered forwardly. A shoulder l within the nose piece contacts with the shoulder 8 of the clamping ring to limit forward movement of the ring.

To reduce the cost of production, it is desirable to make the clamping fingers and clamping ring of a soft, easily workable metal, such, for example, as brass, aluminum, duraiuminum, German silver, copper, or alloys of such metals. According to the present invention, those parts of the soft metal which are exposed to strong friction, such as the parts marked '41 and 48 in Fig. 1, have applied to them coating or covering layers 49 and 50 of a hard wear-resisting metal, which preferably is also resistant to'acids and non-rusting. Suitable metals for this purpose are nickel, chromium, tungsten, iridium, platinum, palladium, molybdenum, and the like. These wear-resisting coatings or linings greatly increase the life of the clamping parts, without unduly increasing the cost of construction.

As above stated, the loosely connected to or clamping fingers I are hung from the forward end of the lead tube 9. This leadtube has a shoulder l1 cooperating with the surface ii of the stationary member 1, to limit rearward movement of the tube so that the clamping fingers cannot be drawn too far rearwardly through the ring is already at the rearward limit of its motion, particularly when there is no lead in the tube, thus avoiding Jamming and injury of the parts. The tube also has a shoulder l9 cooperating with a surface It on the stationary member 1, to limit forward movement of the tube and prevent the feeding fingers from being jammed against the front wall of the nose piece II. To the extent permitted by these shoulders 11 and it, the lead tube 9 may move longitudinally within the pencil casing, and is constantly urged rearwardlyby a coiled spring 9' which presses at its forward end against the stationary member 1 and at its rear end against the lead tube or some part connected thereto, such as the member 21.

In the preferred form of construction, the member 21 is divided longitudinally into two pieces, for ease-of assembly, and constitutes the bottom of a lead me or reservoir. The side walls 22 of the magazine are fixed, as by means of an annular groove 29, tothe bottom member 21. The magazine is slidable axially or longitudinally within the main metal casing member or tube 2|, which may be surrounded by an exterior sheath or sleeve 20 of any suitable material, such as an artificial mass. The upper end of the magazine walls 22 may be provided with a screw thread 23, for engaging a'threaded armular member 24 the upper end of which is closed by a plug 25 having an annular flange 26 which may be conveniently grasped for unscrewing the members 24 and 25 from the magazine walls 22. when the closure is thus unscrewed, the interior space SI of the lead magazine may be filled with leads, which will rest on the conical surface 29 of the bottom member 21, and one at a time the leads will fall into and fill the space 3! within the lead tube 9. v Frequently it is desirable not to fix the magazine bottom 21 rigidly to the lead tube 9, but to provide for some relative movement between these parts at each feeding operation, so as to disturb the leads within the magazine and prevent them from jamming therein. To this end,-

annular flanges 32. and 33 may be formed on the! tube 9, the flange 32 being located within an annular recess in the member 21, which recess has a rear end 34 and a forward end 35. The forward limit of movement of the tube 9 relative to the magazine member 21 is defined by contact of the flange 32 with the surface 35, while the rearward limit of relative movement is defined by contact of the flange 33 with the front end of the member 21 and simultaneous contact of the flange 32 with the surface 34, thus giv-' ing a good bearing on two parts so that too 35' heavy a stress on a small area of the tube 9 during a forward feeding operation is avoided. when. the tube it moves rearwardiy relatively to the magazine bottom 21, upon pushing down' on the cap 26, a projection 36 on one side of therear end of the tube 9, shaped. somewhat likethe point of a shovel, enters the lead space 30 in the magazine and disturbs the leads therein, pushing aside any leads blocking the filling opening and facilitating the sliding of a single lead into the filling tube 9.

The form of the lead pencil described may be altered in different ways within the scope of the present invention.

Working of the the clamping-sleeve II and the clamping-ringwheld firmly thereto by adhesion and holding the said clamping-sleeve together, is pressed forward until the shoulder 8 rests upon the pro-' jection HI. v

'Further forward movement of the tube ,gg' caused by further pushing upon the cap 28, causes the clamping sleeve 0 to slide forwardly through the clamping ring 4, since the ring can not move any farther forwardly. The frictional adhesion between the sleeve and the ring is thus r d-# ually lessened, until it is overcome by the force of the spring 5, which then returns the clamping ring to its rearmost positio thus completely releasing the clamping fingers from the.

lead and permitting the fin ers to spread far casing.

apart so that they will not bind or drag on the lead when they move rearwardly. The cap 26 is then released, and the spring 9' -moves the cap, the tube 9, and the clamping sleeve 0 rearwardlyywithout changing the position of the lead. .Duri'ngthis movement, the fingersof the clamping sleeve are drawn rearwardly through the clamping ring, which cannot move any farther rearwardly, and near'the end of this rearward movement the relative motion between the fingers and the ring causes the fingers to clamp upon the lead, holdingit' firmly for writing until further advancement of the lead'is needed. Then, when feeding is desired, forward movement of the cap 26 moves the tube 9 and the clamping fingers 0 forwardly, the clamping ring 4 adhering frictionally to the fingers and moving forwardly with them against the force of the spring 5, so that the fingers remain tightly clamped on the lead and advance the lead, until the fingers are released near the forward end of the movement, as above explained.

It is now seen that an improved pencil has been provided, in which the lead is effectively gripped and completely released at the proper time. With this improved design and construction, the lead is gripped much closer to the nose of the pencil than in the prior construction i1- lustrated in said Patent No. 1,969,085, with the result that less lead is wasted at the end of each piece or stick, and the lead is held more satisfactorily. Also, .in this improved construction the lead is released more completely and satisfactorily than in the prior construction, so that all danger of accidental rearward movement of the lead is avoided.

Another advantage of the present improved construction is that the nose piece II may be readilyv removed for cleaning the clamping fingers, when required, without causing any of the other parts to become loose or fall out. It is seen from Fig. 1 that the nose piece is screwed onto the forward end of the main casing parts. When it is unscrewed and removed therefrom, the clamping fingers are readily accessible for cleaning, especially if they be pushed forwardly by pressure on thecap 26. In spite of the removal of the shoulder ill of the nose piece out of the path of the shoulder 8 on the clamping ring, the clamping ring still can not drop out, ash; is held in place by its fiange or shoulder 8, which can not; pass through the front ofthe Certain features disclosed but not claimed herein, and particularly the construction of the lead-magazine, are claimed in my companion application for Magazine for leadpencil, Serial No. 708,802, filed January 29, 1934.

I claim:

1. A mechanical pencil comprising a casing havinga nose of external cross sectional dimensions decreasingtoward its forward end, said having a nose whose external sides converge tomay lie within said portion of said cavity-closely adjacent saidjforward end of said nose, and

means for-closing said fingers upona lead near the rear end of a reciprocation of said fingers and releasingsaid fingers fromsaid lead near the forward end or a reciprocation.

2. A mechanical pencil comprising a casing having a nose at least partially tapered toward its forward end, said nose having therein a cavity having a portion alsotapered with thesmaller 9 end of saidportion of said cavity closely adjacent said forward end of said nose, lead 'grasping means mounted for forward and backward reciprocation within said casing, said grasping means including a plurality of fingers movable laterally toward and'away from a lead and having terminal portions taperedtoward their forward its forward end, said nose having therein a cavity having a portion shaped to contract toward said forward end with the smaller end of said portion of said cavity closelyadjacent said forward end of said nose, lead grasping means 35 portions may lie within said converging portion of said cavity closely adjacent said forward end of said nose, said fingers also having, rearwardly of said terminal portions, other portions with outer sides diverging gradually toward said forward ends andrelieved suddenly at their rear ends, and a clamping ring surrounding said fingers and adapted to cooperate with said diverg.-' ing portion to clamp said fingers upon a'lead and to move ofi of said diverging portions past the relieved ends thereof to unclamp said fingers and free them for substantial movement away from. a lead.

4. A mechanical pencil comprising a casing, a tube mounted for reciprocation within said casing, a plurality of lead-engaging fingers operatively connected to said tube and extending for wardly therefrom, and a clamping member also 60 movable within said casing, said clamping member including a tubular portion of one size cooperating with said'fingers to cause them to clamp a lead and a tubular portion of a different size extending rearwardly and at least partially 65 encircling said tube near its forward end.

5. A mechanical pencil comprising a casing, a tube mounted for reciprocation within said casing. a plurality of lead-engaging fingers operatively connected to said tube and extending forwardly therefrom, a clamping member also movable within said casing, said clamping member including adjacent its forward end a tubular portion of smaller size at least partially encircling said fingers and cooperating with them to cause 7 operatively connected thereto to tend to move said clamping member in a rearward direction.

7. A mechanical pencil comprising a casing, a plurality of lead-engaging fingers mounted for forward and backward movement within said casing, said fingers having portions tapered externally in a rearward direction, abutment means within said-casing, and a finger clamping member movably mounted in said casing, said member' including a portion of smaller transverse dimension extending forwardly for cooperation with said fingers to cause them to clamp a lead, and

a portion of larger transverse dimension extending rearwardly for cooperation with said abutment means to limit rearward movement of said member. v

8.'A mechanical pencil comprising a casing, a plurality of lead-engaging fingers -mounted for forward and backward movement within said casing, said fingers having portions with exterior surfaces diverging in a forward direction, and a member surrounding said fingers and shaped internally to cooperate with said diverging portionsof said fingers and capable of relative longitudinal movement with respect to said fingers, so that whensaid member is moved forwardly with respect to said diverging portions of said fingers, said fingers will be contracted to clamp upon a lead, and when said member is moved rearwardly with respect to said diverging portions of said fingers, said fingers may expand to free a lead, said fingers being suddenly relieved at the rear ends of said diverging portions so that when said member is moved beyond said rear ends of said diverging portions said fingers may expand to a materially greater ,extent.

9. A mechanical pencil comprising a casing,- -a plurality of lead-engaging fingers mountedv for forward and backward movement within said casing, said fingers throughout portions of their lengths having exterior surfaces diverging in a forward direction and thence converging substantially from said diverging portions to their forward ends, so that said forward ends may lie closely adjacent the forward end of the pencil, and, a member. surrounding said fingers and shaped internally to cooperate with said diverging portions thereof, to cause a clamping action of said fingers upon a lead and to allow release thereof:

ii). A mechanical pencil comprising a casing,

a tube mounted for reciprocation within said casing, .a plurality of lead-engaging fingers operat-lvely connected to said tube and extending forwardly therefrom, a clamping member also movable within said casing for cooperation with gers are reciprocated vanced position normally lying at least partially within said removable nose portion so that said fingers may be rendered accessible for inspection and cleaning by removal of said nose portion, a clamping ring also mounted within said casing for movement back and forth with relation to said fingers to cause said fingers to grasp and release a lead, and means other than said fingers themselves for preventing removal of said clamping ring from said casing in a forward direction notwithstanding removal of said nose portion. a

12. A mechanical pencil comprising a' main casing, a lead holding tube mounted for reciprocation within said casing, a plurality of lead clamping fingers loosely mounted on said tube and projecting forwardly therefrom beyond the forward end of said main casing, a clamping ring having a portion within said main casing and a portion projecting forwardly therefrom and surrounding the forwardly projecting portions of said fingers, and a nose piece detachably secured to said main casing and extending forwardly from the forward end thereof and enclosing the forwardly projecting portions of said fingers and clamping ring.

13. A mechanical pencil comprising a casing having a nose tapered; toward its forward end, said nose having therein a cavity havinga portion tapered toward said forward end with the smaller end of said tapered portion of said cavity closely adjacent said forward end of said nose, lead grasping means mounted for forward and backward reciprocation within said casing, said grasping means including a plurality of fingers movable laterally toward and away from a lead andhaving terminal portions tapered toward their forward ends so that when said finforwardly said terminal portions may lie within said tapered portion'of said cavity closely adjacent said forward end of said-nose, said fingers also having, rearwardiy of said terminal portions, other portions conically tapered-toward their rearward ends; and relieved suddenly at their rear ends, and a clamping ring surrounding said fingers and having a conically shaped inner surface adapted to oooperate with said conically tapered portions of 00 beyond their relieved rear ends to unclamp said fingers and free them for substantial movement away from a lead. 1

AUGUST ms'rnuscnmsmsa.

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