US 1833287 A
Description (OCR text may contain errors)
'-Udl' un r U? lamas? WUH NOV. 24, 1931. F, K HADLEY 1,833,287
COMPOSITION-FOR LIFTING FRICTION SKIN IMPRINTS Filed Sept. l. 1928 Elu-um M01: 2
UNITED STATES PATENT OFFICE FRANK K. RADLEY, OF ST. LOUIS, MISSOURI, ASSIGNOR T0 ST. LOUIS RUBIBIEIR CEMENT COMPANY, 0F ST. LOUIS, MISSOURI, A CORPORATION OF MISSOURI COMPOSITION FOR LIFTING FRICTION SKIN IMPRINTS Application filed September 1, 1928. Serial No. 303,388.
This invention relates to a composition of matter for lifting friction-skin impressions, such as fingerprints, palm prints, sole prints and the like. Fingerprints, as is well known, are impressions from the terminal phalange of the fingers or thumbs, valuable in the identi' fication of individuals because of the fact that their lines, which delineate the ridge configuration of the friction-skin in all its minutize, vary in each individual from all others. It is also well known that this method of identification of persons is practiced extensively by police operators on account of the certainty of its results in identifying criminals. A criminal may unknowingly leave a print of his fingers on some article or weapon that he has touched, and this print may be too faint to be detected until it is brought out more distinctly, which is usually djone by sprinkling thereon or applying thereto by means of an aspirator a finely divided powder, such as bronze or aluminum, that adheres to the faint markings and renders them easily visible by reason of its high lustre or contrast with the color of the surface that is the site of the print. However, ngerprints are often left on surfaces of objects that cannot be removed, and, prior to this invention, the only way to retain a print situated on such an object was to photograph the print after it had been developed by powdering it. Much difficulty, however, is experienced in photographing a fingerprint on a curved surface, such as the neck of bottle that may have been used as a weapon, or on a site that is not accessible to a camera, or fingerprints left in places that can not be properly lighted for taking photographs; and, even when photographs are taken under such conditions, they are not always reliable.
Accordingly, the principal purpose of the present invention is the provision of a composition of matter that may be applied to friction skin imprints on divers surfaces. and
' which, upon withdrawal from such surfaces,
will lift the imprint therefrom.
Other objects and advantages, more or less ancillary to the foregoing, will appear in the course of the following description of an illustrative embodiment of the invention.
In the accompanying drawings forming part of this specification, in which like numbers of reference denote like parts wherever they occur,
Figure l is a plan view, with parts broken away, of the meansfor utilizing the composition of this invention; and
Figure 2 is a transverse sectional view of the same, the thickness being exaggerated for the sake of clearness.
Briefly described, the composition of the invention provides a body having a surface which is suficiently pliable to conform intimately to the surface on which the powdered imprint is situated, which is sufficiently adhesive to retain on its conforming surface the powder to which it is applied, and yet is not liable to adhere so strongly to the imprintbearing surface to which it is applied as to prevent its being pulled away therefrom intact. Preferably a protective covering is detachably applied to the powder-or-imprintretentive surface of the body.
The composition is best used in connection with a flexible base, preferably finely woven fabric 1, having a coating 2 of the composition applied to one side thereof, and a cover sheet 3, preferably of Celluloid or other transparent flexible sheeting, impressed on the coating 2. In order to present a finger print or other friction-skin imprint most conspicuously, the coating 2 should be of a color that forms a strongly contrasting background for the color of the powder, and to this end black is deemed preferable. The fabric is also preferably of the same color, in order to intensify or deepen the color of the coating 2, since the color of the fabric might be faintly visible through the coating 2, especially if the latter is very thin.
The coating 2 is a composition of matter that preferably comprises a rubber base and a quantity of binding and softening material sufficient to give the composition a consistency that will render it suliiciently pliable to follow intimately the surface of the body or object from which the friction-skin impression is to be removed, and suliciently adhesive to lift the powder of the impression from the impression-imparting surface, but not adheo matter.
sive to such a degree as to prevent the composition from being withdrawn intact from the impression-imparting surface. The composition may also contain suitable coloring In preparing the composition it is preferable to use Crepe and Guayule rubber as a base, Cumar R. S. (rubber soft) as a binder, cottonseed oil and petrolatum as softcners,. and carbon black as coloring matter. The best results may be obtained when these ingredients are in the following proportions by weight: Crepe rubber, twenty-five parts; Guayule rubber, eight and one-fourth parts; carbon black, one-eighth part; C umar rubber soft, three and one-half parts; cottonseed oil, two parts; and petrolatum, one part. Y
The rubber is first weighed and thoroughly broken down by the rolls of a mixer.' The various other ingredients of this formula are weighed and mixed in a receptacle, and are then added to the broken down'rubber in the mixer, in which these other ingredients are thoroughly mixed with the rubber.
The prepared compound is then run on a calender machine and impressed on one side of the black woven fabric sheeting that forms the base l. The weaving of the fabric l is suihciently close and fine to prevent the composition from being forced through the interst-ices of the fabric to the opposite side, while at the same time permitting the composition to become thoroughly imbedded in the interstices adjacent to the coated side of the fabric l, thereby firmly uniting the fabric 1 and the coating 2. After this operation. the coated sheeting is then cutto the size of the celluloid sheeting that is to cover the coating 2. The celluloid 3 isthen pressed against the coat 2 of the coated sheet in a machine known to the art as a doubler which forces out all the air which may intervene between the celluloid 3 and the coat 2. vThe finished material is then ready for use, the celluloid adhering detachably to the coating 2.
In lifting a finger print, or in fact a print of the foot or any part of the human body, by means of a sheet coated with the composition of this invention, a piece of the sheet sufficiently large to cover the imprint is cut from the prepared sheet, reserving the residue for future use. The usual powdering process is then employed to develop the impression, wherever it may be, whether on metal, wood, glass, or on any smooth surface. The celluloid covering of the piece of sheet material is then lifted from the coating underneath andthe coated side of the cut piece is impressed against the powdered imprint, and the imprint adheres to the coated side and is lifted off perfectly with it from the surface to which it has been applied when the cut piece is pulled away from said surface. The lifted celluloid is then replaced on the cut piece to protect the impression retained on the coating thereunder, thereby imprint from the glass in the same manner as described above. Another method of taliing an impression from theJ body consists m 4powdering -the glass, then pressing the foot `or other portion ofthe body on the glass,
and subsequently pressing such portion of the body on the imprint-receptive, material of this inventioxawhich will leave a perfect print thereon, the ridges of the skin receiv- "ing the powder fromthe glass and transferring it to the contiguous surface of the composition rl`he iiexibility of the sheet of lifting material enables it to be applied to curved and irregularf surfaces;
Having thus Afullydescribed this invention, I hereby reserve :the benefit of all changes in form, arrangement, order, or use of parts, as it is evident that many minor changes may be made therein Without departing from the spirit of this invention or the scopeof thefollowing claims.
I claim: i
1. A composition for lifting friction-skin imprints, comprising substantially by weight twenty-five' parts of Crepe rubber, ten parts of Guayule rubber, one-eighth part of carbon black, three parts of Cumar soft rubber, two parts of cottonseed oil, and one and one-half parts'of pine tar.
2. A composition for lifting friction-skin imprints, comprising a rubber base and a quantity of soft rubber and cottonseed oil sufficient to give the composition a consistency` that will render it sufliciently pliable to follow intimatelv the surface of the object from which the friction-skin impression is to Abe removed and sufficiently adhesive to lift the powder of the impression from the impression-imparting surface.
' 3. A composition for lifting friction-skin imprints comprising Crepe and Guayule rubber, Cumar soft rubber, cottonseed oil and a coloring agent.
4. A composition for lifting friction-skin imprints comprising Crepe and Guayule rubber, Cumar soft rubber, pine tar and a coloring agent.
In testimony whereof I hereunto aiix my signature.
FRANK K. HADLEY.