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United States Patent 3,523,741
“Lead Pencil Having Means Adapted to Control the Drop of the Refill Lead”, 1965–1970

date of application
date granted
inventor
assignee
patent holder country
1965 September 30 (Italy)
1970 August 11
Giulio Gigli, Baranzate, Milan, Italy
Ardis S.p.A., Baranzate, Milan, Italy
Italy
Filed in U.S. Sept. 20, 1966, Ser. No. 580,665
Claims priority, application Italy, Sept. 30, 1965, 21,782/65
Int. CI. B43k 21/22; U.S. CI. 401-94; 1 Claim

Lawrence Charles, Primary Examiner
patent employed on rotring 1305
rotring 1305 drafting leadholder
references cited
United States Patents:
261,500   7/1882   Uhlig   401-94
326,737   9/1885   Hoffman   401-94
338,611   3/1886   Pusey   401-94
340,925   4/1886   Sandell   401-94
Foreign Patents:
1,173,362   7/1964   Germany    

Abstract of the Disclosure

A pencil having means adapted to control the amount of lead projecting from the sheath and preventing accidental removal of the lead. A chuck holds one end of the lead, selectively, in both projecting and retracted positions. The other end of the lead fits into and is held by a small tube mounted in the sheath for restricted axial movement.

 

This invention relates to a pencil, of the kind comprising an external sheath adapted to house the lead, a chuck, adapted to hold said lead, and means, comprising a spring-biased pushbutton, for manipulating said chuck.

An object of the present invention is to provide a controlled ejection of the lead, that is, to arrange so that the point of the lead, once the pushbutton is pressed thus opening the chuck, protrudes by a preselected distance.

This object and other considerable advantages will be described as the disclosure proceeds, and is achieved with the inventive pencil, a member connected to the lead in an axial adjustable relative position, said member being slidable within the sheath as an entity with the lead when the chuck does not hold said lead, and slidable with respect to said lead when the latter is held by said chuck; means adapted to restrain the stroke of said member, and consequently of the lead in either direction, so that, whenever the pushbutton is depressed so as to cause the chuck to open and allow the lead to descend, the latter cannot come out of the pencil completely due to its being held by said member which is arrested at the end of its stroke; means being further provided for allowing the manipulation of said member from the outside so as to vary the relative position of said member with respect to said lead when the latter is being held by said chuck.

In order that the features and the advantages of the inventive pencil may become fully apparent, an embodiment thereof is described in the following with reference to the accompanying drawing, wherein:

FIG. 1 is an axial partial sectional view of the propelling pencil, showing the chuck open;

FIG. 2 is another axial partial sectional view of same propelling pencil, showing the chuck closed, and

FIG. 3 is a further axial partial sectional view showing the chuck closed with a lead projecting by a certain distance.

The pencil according to the present invention comprises an outer sheath 7 enclosing a metal tube 2 to which the lead-holding chuck 8 is solidly and screwably affixed by a portion 10 and whose jaws 9 constitute the lead-holding members proper.

A metallic tubular body 5, acting as a pushbutton, has a cutaway window 11 having a certain width, extending along a considerable portion of the length of said body. The pushbutton 5 is threadably affixed to said tube 2 so that the pushbutton 5, the tube 2 and the chuck 8 are a solid entity.

Between an abutment 12 of the sheath 7, and the pushbutton 5 a spring 13 is mounted so that, by depressing the pushbutton 5 so as to cause it to penetrate the sheath 7, said spring is compressed, whereas, as the pushbutton is released, the spring urges the pushbutton into the position of maximum protrusion (as viewed in figs. 1, 2, 3). As the pushbutton 5 is depressed, the chuck 8 (solid therewith) is also displaced in the axial direction so that the jaws 9 protrude outside by an increased distance allowing the jaws 9 to expand outwardly to open the chuck; by releasing said pushbutton, said chuck is closed again (that is it takes the configuration shown in figs. 1, 2, 3). Internally and coaxially with the tube 2, a small metal tube 1 is provided, the latter having a clearance which is sufficient to allow it to freely slide within said tube 2; more particularly, by tipping over and then resetting the pencil in the vertical direction, the small tube 1 is caused to reciprocate.

To the upper portion of the small tube 1 a knurled collar, shown at 3, is solidly affixed. Within the small tube 1 a lead 4, whose diameter is slightly less than the inside diameter of the small tube, can be slipped, said small tube 1 having, in its lower portion, a few longitudinal slits 14 by virtue of which the tube is allowed slightly to clamp the lead 4 in said portion, holding it fast: however, the lead can be caused to slide within the tube by applying a slight force.

Let it be assumed that, at the outset, the lead 4 is not present in the above described pencil. By holding the pencil vertical with its point down (i.e. with the pushbutton 5 pointing upwards), the tube 1 is in its lower dead center with respect to the pushbutton 5: stated alternatively, it is in the position in which the collar 3 abuts the uppermost end 15 of the tube 2. By squeezing the pushbutton 5, the chuck 8 is opened, and so the lead can be slipped thereinto: the latter, entering the tube 2, abuts the lowermost edge of the small tube 1 pushing said tube upwards; thus, the small tube 1, is caused to slide until it is stopped when the collar 3 abuts pushbutton: from this instant of time onwards, the lead penetrates the small tube 1.

The lead is inserted into the tube 1 until such time as the point of the lead reaches the level of the lower edge of the chuck, as shown fig. 1. Now, by releasing the lead, the latter will fall together with the small tube 1 (which descends along with the lead since its lower end is slightly clamped onto the lead): said descent corresponds to the length of the headroom within the pushbutton 5, that is, the descent is terminated as the collar 3 abuts the upper end 15 of the tube 2. At this stage, the pointed end of the lead projects downwardly from the chuck by a certain distance. By releasing the pushbutton 5, the chuck clamps the lead 4 (the jaws 9, with their knurled surface lock the lead) and the pencil is ready for use (see fig. 3). As the operation is finished, if the pushbutton 5 is squeezed and the pencil is held upside down (chuck 9 upwards), as soon as the chuck releases the lead 4, the latter, along with the tube 1, falls back within the pencil so that, by releasing the pushbutton again, the chuck clamps the lead (which is wholly withdrawn) and the pencil can be put aside.

During use, a possible shortening of the projecting portion of the lead, due to wear or breaking, can be compensated for by causing the tube 1 to slide upwardly: this is obtained by pulling the collar 3 upwards manually (the knurled surface of the collar 3 facilitates the manipulation); thus, inasmuch as the lead is held by the chuck 8, the tube 1 slides upwards while the lead is stationary, that is, a relative motion takes place between the tube and the lead, said motion being possible in that the lower portion of the tube slightly clamps the lead. By depressing the pushbutton 5 again, the tube 1 is restored to its lowermost position and is moved together with the lead, the latter being caused to protrude by a desired distance and, under these conditions, it is held by the chuck as the pushbutton is released.

The pushbutton 5 has, at its top, a threaded cap 6: removing the cap 6 the tube 1 can be withdrawn whenever a cleaning operation is necessary for removing dust and foreign matter and, more particularly, in the case in which, by inadvertent manipulation of the collar 3, the lead 4 enters the tube 1 to such an extent as to be incapable of being seized by the chuck, a correct operation becoming thus impossible.

If this is the case, once the cap 6 has been removed, the tube 1 is withdrawn, the lead 4 is removed from the tube 1 and the latter is positioned within said tube 2 again, whereafter the cap 6 is replaced, the lead is inserted in the pencil again at the chuck end by keeping the pushbutton 5 depressed with the pencil held with its point down and, eventually, the pushbutton is released.

Among the several considerable advantages of the inventive pencil, it should be noticed, more particularly, that it is possible to have the lead protruding by a controlled distance which could be the one which is ideal for universal use and, more particularly, for the use of lead sharpeners which necessitate that the lead protrudes by a preselected distance. Once the use is finished, the withdrawal of the lead is permitted so as to preserve the sharpness of its point.

It is possible, when the lead is clamped (by manipulating the collar 3) to vary the length of the protruding portion of the lead, which, once it has been preset by the manipulation of said collar, can be obtained whenever the pushbutton 5 is depressed by holding the pencil with its point down. By depressing the pushbutton and holding the pencil with its point upwards, the lead will be withdrawn, ready to be projected outwards on the subsequent manipulation.

What is claimed is:

1. A lead pencil comprising a substantially cylindrical sheath, chuck means movably mounted in and extending from one end of said sheath, pushbutton means on the other end of said sheath operatively connected to actuate said chuck means, said pushbutton means comprising it pushbutton, a cylinder affixed to and depending from said pushbutton and extending axially into said sheath, a longitudinally extending slot formed in said cylinder, spring means biasing said pushbutton means to normally expose said slot, a substantially tubular member adapted at its lower end to slightly clamp the lead, collar means formed on the upper end of said member and being provided with a plurality of externally directed ridges forming a substantially knurled surface, said member being axially adjustable relative to the lead, said member being slidably mounted within said sheath together with the lead when the chuck does not hold the lead and being slidable with respect to the lead when the latter is held by said chuck, said slot providing access to adjust said member with respect to the lead and providing limit stops for said collar to control the maximum inward and outward movement of said lead when said chuck is opened.