US1892508A - Lead pencil and method of making the same - Google Patents

Description

Dec. 27, 1932. N. GONZ'ALEZ 1,892,508

LEAD PENCIL AND METHOD OF MAKING THE SAME Filed March 27, 1931 INVENTOR Faraso Gan BY 67. Adan, v ATTORNE S Patented. Bee. 2?, 1932 PATENT NARCISG GONZALEZ, OF NEW? YORK, Y., ASSIGNOR TO EAGLE PENCIL :ZZOMPANY, 01" NEW YORK, N. 1., A CORPORATION OF DELAXVAEE LEAD PENCIL AND METHOD OF MAKING THE SAME Application filed March 27, 1931. Serial No. 525,863.

This invention relates generally to the manufacture of pencils and has reference to ways of preparing leads or crayons so as to get a good adhesion between them and an outer sheath or casing when the various parts of the pencil are glued or cemented together.

In the manufacture of pencil leads or other forms of marking material for pencils, it is customary to include in the material of which they are composed various greasy or oil materials such as tallow, stearic acid and the like. These greasy or oily materials are u ed in various ways and in varying proportions according to the nature or kind of mark it is desired to hav lie. ,encil make. All of them are a source OI diillculty in get-ting a good adhcss. of the marking material to the Gas r as a result, the leads often have no 'a ing them to the interior of the cashond 2 1 ing because the glue or other adhesives commonly used cannottake hold upon thc greasy surfaces.

An object. of this invention is to change the greasy surfaces of such leads or marking material so as to remove the greasy etliect and then give the pieces of marking material a coating of a material which Will prevent grease from exuding from the interior of the marking material and which coating will at the same time give a surface to which glues and cements will adhere.

My present invention considered from one aspect relates to the leads themselvesas new articles of manufacture; considered from another aspect relates to the structure of the complete pencil, andfroin a further aspect it is concerned with a method of treating the leads.

The result indicated may be obtained in various ways but a satisfactory Way of carrying out the process is stated below. That statement or description is, however. intended only tc he a representative one and it is not the intention to limit the invention to any one particular way of practicing it.

The invention particularly. ltlsulu as it relates to th cinn lctc pencil nnrv he more fully understood hy rrter-ancc t-:: the mom panying drawin wherein Fig. l is a disassemliled view showing a pencillead about to be assembled in its sheath, and;

Fig. 2 is an enlarged transverse sectional View through the completely assembled pencil.

After the leads have been prepared. in the form they are to ha ve when as embled in pen- Oils they are immer ed in sulphuric acid for I fztl t'llig periods of time depending upon the depth to or?! the tr .in n is desired to go and the concciuiuition of the acid. Sal phuric acid has the advantage of carbonizing any organic grease and thereby removing or destroying the great-e ctl'cct. After this treatment in the acid thclead -1 may lie-washed in water. This washing may he carried out in a centrifugal machine or h any other pram tical means. llhe leads are then given a seeond treatment v-Jith dilute sulphuric acid and while the acid is adhering to them the leads are immersed in a solution of soluble salts which by reaction with the acid will prccipitate on the lcadsin an insoluble form: A. satisfactory salt solution one oi calcium chloride but there are other materials whit-h answer the purpose equally as well. 'lf'l'ic insoluble prccipita'liou of calcium he the lead will serve as a casing or seal which will prevent the grcasv material in the hodv of the lead from exu: mg and will also form a very -'atis'fact ry surface for th" dhesion of glue or cement when the penci. lo ing assembled.

The two treatments with the sulphuric acid are pre lcrrezl because of the fact that a speedicr operation possihle. ll o cre" steps may be coml-inrd. particular hrst acid bath is sullicicn liluta-d.

til) at tl c load. In Fig. 2; l have shown on an cxa geritrd scale t e thickness t to coating which 1 on the lead and t thickness of the {glue whi -ir s int tcgct h :5- r

tween such coating and the pencil sheath and which intimately bonds the lead coating to the sheath. Here it will be observed that the lead 10 is provided with the grease impervious coating 12 formed by the process explained above and having an outer surface which will firmly adhere to the glue indicated at 13 which unites the coating to the sheath. This glue, of course, also serves to secure the two sections of the sheath together, although I have not exaggerated the space between the sheath sections to indicate this.

Results which are on the Whole satisfactory have been obtained by mechanically treating the surfaces of the leads to remove the surface grease and then carrying out the acid and precipitating treatment as before. However, the acid treatment is: more convenient and satisfactory in results and is naturally preferred.

As above stated, the invention can be carried out in various ways and it is, therefore, not desired to be limited to any particular Way except as such limitations may appear in the claims which follow.

What is claimed is:

1. A method of coating pencil leads which comprises treating the surfaces of the leads with sulphuric acid and then, while acid is adhering to said surfaces, immersing the leads in a solution of calcium chloride.

2. A method of coating pencil leads which comprises treating the surfaces of the leads with sulphuric acid, washing the leads with water, immersing the leads in a weak solution of sulphuric acid, and then immersing the leads in a solution of calcium chloride.

3. A method of coating pencil leads which comprises subjecting the leads to an acid treatment, and then chemically precipitating on said surfaces an insoluble material which will resist penetration by grease.

4. A method of coating pencil leads which comprises treating the surfaces of leads contaimng greasy material with an acid, and then precipitating on said surfaces a reaction material developed from the acid and a salt which will prevent grease from exuding from the leads.

5. A method of treating pencil leads which com rises treating the leads with an acid capa le of destroying surface grease, and then coating the leads with a material which will adhere to the surfaces of the lead and prevent grease from exuding through the coating.

6. A method of treating pencil leads which comprises treating the leads to remove surface grease, and then coating the leads with a material which will prevent grease from exuding through the coating and which will serve as a binder between the lead and the casin when the pencil is assembled.

7. i method of treating pencil leads which comprises destroying or removing surface thereof and a grease impervious coating at the outer surface of the lead intimately adhesively bonded to the sheath.

9. A lead pencil including a. lead, a sectional sheath thereabout and a binder means interposed between them preventing exudation of grease from the lead and intimately adhesively attached to the sheath.

10. A lead pencil including a sheath, a core of marking material of the type normally subject to grease exudation, adhesive between the core and sheath, and means preventing grease exudation from the core and establishing an intimate bond between the core and the adhesive material.

11. As a new article of manufacture a pencil lead having a grease impervious coating.

12. As a new article of manufacture a pencil lead having a grease impervious coating, the exterior surface of said coating being inherently adapted for intimate adhesive bonding to an enclosing sheath.

13. As a new article of manufacture a pencil lead having a coating of calcium sulphate.

In testimony whereof I hereto aflix my signature.

NARCISO GONZALEZ.

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