US2938374A - Protection of combination locks against entry by radiography - Google Patents

Description

May 31, 1960 E. L. CRISCUOLO ETA 2,938,374

. PROTECTION OF COMBINATION LOCKS AINST ENTRY BY RA GRAPHY Filed June 1957 FIGJ. FIG.4.

GO D-O OCXYYXXX] INVE ORS.

I 31 EDWA L. c CUOLO DAN POLANSKY DONA D P. CASE BY jl/flb;

ATTYS.

United States Patent PROTECTION OF COMBINATION LOCKS AGAINST ENTRY BY RADIOGRAPHY Edward L. Criscuolo, 10803 Keller St., Silver Spring, Md.; Daniel Polansky, 11123 Dewey Road, Kensington, Md.; and Donald P. Case, 702 Brantford Ave., Silver Spring,

Filed June 24, 1957, Ser. No. 667,725

8 Claims. (Cl. 70333) (Granted under Title 35, US. Code (1952), sec. 266) The invention described herein may be manufactured and used by or for the Government of the United States of America for governmental purposes without the payment of any royalties thereon or therefor.

The present invention relates to a protected combination lock, and more particularly to the protection of a combination lock against entry thereof by radiography, and a method and means for affording said protection.

Present day combination locks employ tumblers and arrange them in a manner that the lock is fairly well protected against mechanical manipulation thereof. However, X-rays or other penetrating radiation may be used to locate the positions of the openings or gates in the tumblers and thereby determine the combination of the lock. Moreover, with the development made in portable penetrating radiation sources in recent years, a safe or tered on the premises by a radiographic method and the combination setting of the lock can be obtained within a relatively short period of time without leaving any visible evidence of such compromise, This possibility has been recognized by those working in the lock art and it has been proposed to modify the construction of the tumblers to the end that the tumbler openings cannot be rendered visible from the exterior of the lock casing by the use of X-ray or the rays of radioactive isotopes, see US. Patents 1,847,071, 1,925,980 and 1,928,- 853 to William F. Doenges. However, such measures were not completely successful for the reason that the X-ray absorption characteristics of the materials employed were such that a sufficient definition of the tumblers could be obtained under appropriate conditions with the result that the combination could be determined for unlocking the lock.

In accordance with the present invention, the tumblers of the lock are formed of material having low X-ray absorption characteristics, a shield of material having high X-ray absorption characteristics is provided around the lock, and finally the shielded lock is located between members of material having X-ray scattering characteristics.

It is therefore an object of the present invention to provide a lock protected against entry by radiography.-

Another object'is the provision of a lock having tumblers therein of a suitable plastic material, such, for example, as Tefion or nylon.

A further object is to provide a lock having tumblers of a material having low X-ray absorption characteristics, such as nylon and a shield thereabout of material having high X-ray absorption characteristics, such as lead.

A final object of the present invention is the provision of a lock having plastic tumblers and lead shielding, and disposed between members of X-ray scattering material, for the purpose of preventing sufficient definition of the tumblers and thereby preventing compromise thereof by radiography.

container protected by a combination lock may be en- With these and other objects in view, as will hereinafter more fully appear, and which will be more particularly pointed out in the appended claims, reference is now made .to the following description taken in connection with the accompanying drawing in which:

Fig. 1 illustrates schematically the arrangement of the critical parts of a lock protected in accordance with the present invention, and the relation thereof with respect to an X-ray source and an X-ray film;

Fig. 2 is a side elevation, in section, of a conventional combination or permutation lock protected in accordance with the invention;

Fig. 3 is a sectional view taken on line 3-3 of Fig. 2, looking in the direction of the arrows; I

Fig. 4 is a fragmentary view of one form of X-ray scattering material; and

Fig. 5 is a fragmentary view of another form of X-ra scattering material.

Referring now to the drawings, wherein like reference characters designate like or corresponding parts throughout the several views, therein is shown in Fig. l a schematic arrangement serving to illustrate the principle of operation of the present invention, the reference character 11 designating lock tumbler material having low X-ray absorption characteristics, which in turn is flanked on all sides by' shield material having high X-ray ab.- sorption characteristics and designated by reference character 12 The tumbler material is also flanked on all sides by material 13 which has the properties of scattering X-rays, the shield material 12 being disposed between the scattering material 13 and the tumbler material 11. A suitable source of X-rays, or radiation from a radioactive isotope, is designated by reference character 14, while reference character 15 designates suitable film for exposure to the radiation which passes through the lock and associated parts to form a radiograph thereof.

Turning now to Fig. 2, which shows the invention applied to a conventional combination or permutation lock, with parts in section for a better understanding of the relationship therebetween, reference character 16 designates a portion or panel of the safe or container upon which the lock is mounted, the lock, except for the tumblers thereof, being of conventional character and having the usual operating shaft 17, one end thereof being disposed within the safe or container, the other end disposed exteriorly thereof. The exterior end of the operating shaft 17 carries a conventional numbered dial 18 and an operating knob 19, the safe or container panel 16 having thereon a suitable index mark [not shown] at the periphery of the dial.

The inner end of the operating shaft 17 extends into a box or casing 21 and is secured to a primary driving wheel 22 disposed in the box, the Wheel being rotatable through the medium of the operating knob and shaft. Box 21 has a back plate 23 and fixed thereto is a hollow post 24 into which the inner end of the shaft 17 telescopes, the post being adapted to support a plurality of rotatable members 25 which are retained thereon by means of a resilient snap ring or retainer 26 adapted to seat 'within a groove formed in the post adjacent the free end thereof. The rotatable members 25 are maintained in spaced relation on the post by using washers which are connected to remain fixed to the post and serve to prevent the transmission of rotation of one of the rotatable members to the adjacent rotatable member except through the pin and fly" connection between the rotatable members, neither the washers nor the pin and fly connections being shown, but readily understood by those skilled'in the art.

A pin and fly connection also exists between the primary drive wheel 22 and the rotatable member 25 nearest thereto, whereby said rotatable. member may be rotated by turning the operating knob 19. Because of the pin and fly connections between the rotatable members 25, the rotation of the first such members is transmitted to the neat member and so on through the several members arranged on the post. Thus, by proper manipulation or turning of the operating knob, according to the combinatiori or setting of the rotatable members 25, these members are brought into a predetermined relationship which permits releasing of the lock mechanism and the nnlo cking of the safe or container.

' Ordinarily, each of the rotatable members 25 is made in two parts, an inner part 28 rotatably mounted on the Pa t aflslansi er p 29 ri by s i n rat the outer periphery of the inner part and the inner periphery of the orrter part being suitably serrated for intermeshing connection to each othen thereby providing for the outer part to he slipped off and set with respect to the inner part, suitable indic'ia being provided whereby any desired set: .ti ng may be made. The outer part 29'constit'utes a tumbier or tumbler Wheel and has formed in the outer periphery thereof a notched opening or gate 3 l, the setting or combination .of the openings or gates being determined In the event future technological developments make it po'ssible to detect the tumbler openings, "each tumbler could also be provided with several dummy gates which would have therein a thin web of material to prevent the by setting eachouter part 29 with respect to its inner part 28, as .hereinbefore described. When the tumbler openings or gates have been rotated into alignment by proper manipulation of the operating knob according to the cornhination or setting of the terminal, the fence end of the lock bolt (not shown) can move into the aligned openjhgsto permit releasing of the lock mechanism by turning ,of theo'perating lrnob 19. The hereinbefore described parts ,of'the lock, and the operation. thereof, should be readily understoodby those skilled in the art and further description thereof appears unnecessary. i

' In the application'of this invention to theconventional lock ,hereinbefore described, firstly, the outer part 29, in whichjs formed the tumbler opening or gate,'is madeof a material having low X-ray absorption characteristics; that is, a low density material such as nylon, Teflon, Bakelite, etc. Secondly, the box 21 is contained in a housing 32 made of material having high X-ray absorption characteristics; that is, a high density shield material, such .as lead or the .likeQa suitable bo're or opening 33 being provided therein for passage of the operating shaft 17 therethrough. Thirdly, the box is flanked ,onall six sides by layers of material 34 havinghigh X-rayscattering characteristics and disposed exteriorly ofthe shield .a a srialt flEheXray scatter material may take several forms, such sfiS, a plain' .steel iplate, aplate with drilled holes, or a layerp'f steel balls. Fig. 4 shows a steel plate 35 drilled with holes 36, the holes being inch in diameter and spaced /2 inch on centers with the maximum number of holes possible being drilled in the plate, .the thickness thereof being 3/ inch. Fig. 5 illustrates Xsray scatter material-intheformo'f a layer of steel balls 37, preferably FA ch diametenlsuc h layer of balls being adapted to h spata iwdii h s i li vus ns a -Part bf which suitably hollowed out to'receive the .b'alls, the balls being held ,in 1 place ;by means .of. plates secured ,to the housing,

. orby being moldedin amatrix of plastic 38, as illustrated In n ofthe te t 0 th inten n m iasfien-ls wasfitted with three Mi inch nyloh turnbers, with the vappropriate notched openings or gates therein. Placed on I allsigr sides of vthelock was /2 inch leadshield material and inch diameter steel balls. Thus, the radiation p t ex sndq 1th v th t 1%? n yl mmb st -the total of l inch of lead and two layers of inch diameter steel balls. .placedon a file drawer anda radiograph-was tak e -em- 'ploying-a radioaetive source. :Inthe ;r adiograph,;althongh various parts of the lock were visible, the notched .op en- '=ings ton-gates in .the tumblers were undefinedand lOSt. fSUCh lOCkS are considered :fully protected against entryby -radiographic methodss-or means: v

he la k as rat s? wa materi fence of the lock from entering therein. Extreme dithculty will therefore be encountered in determining the true tumbler gates or openings, thereby concealing the proper settings thereof for protection of the lock against adve csd ra i sranhi me h d an means- -.Con,siderati on of all the factors effecting the protection of combination locks from radiographic comprise has lead to the selection of low density tumbler material because of the diflicultdetection problem presented thereby, the use of lead shielding for limiting the selection of radition sources to those with high energy, and the employment of efficient scattering material for scattering the radiation rays; Presently, the optimum protective system is considered to consist of nylon tumblers, a /2 inch of lead on each side, and a layer of /4 inch diameter steel balls outside the lead. With this system, as much as 0.7 inch of nylon can be utilized in the lock without being detected radiographically.

' From the foregoing, it should be apparent that'there has beenprovided a combination lock which is fully proaga'inst compromise by radiographic means or methods and that such protected lock represents an embodiment of the present invention.

Obviouslym'any modifications and variations of the present invention are possible in the light of the above teachings. It is therefore to be understood that within the scope of the appended claims the invention may be practiced otherwise than 'as specifically described. I What is claimed as new and desired to be secured'by Letters Patent of the United States is:

'1. A loch protected agains radiographic compromise, comprising a lock including tumblers made of a low density material, a casing for said tumblers, a housing contacting said casing for shielding said tumblers, said housing being of a high-density, X-ray absorbing material, and layers of material contacting said housing and having the capability of scattering penetrating X-ray radiation impinging thereon.

A lock protected against radiographic compomise, comprising a lock including tumblers made of a low density material, a housing surrounding said tumblers for shielding the same, said housing being of a high density material, and layers of material flanking said tumblers and having the capability of scattering penetrating radiasign impinging thereon, said layers of material being metal l st sihi' ii hl reas f m d t e 3. A look protected against radiographic compromise,

. A look protected against radiographic compromise,

said lockcomprising a housing made of material having high X-ray penetrating radiation absorption characteristics and formed with an internal chamber, said housing having exterior'portions thereof flanking said chamber and holdowedout for providing shallow cavities therein, X-ray penerating radiation scattering material disposed in each oi said cavities, lock tumbler and casing means contained incsaid chamber, said casing means being in contact with said housing, and said tumbler means being made oi a hat iri ,l .X-re Pe -F ing r io a 5. A lock as defined in claim 4 the materiallof Bassist betas has}. sad th states hes bstwssas 5 chamber and said scattering material being at least onehalf inch.

6. A lock protected against radiographic compromise, said lock comprising a housing made of material having high penetrating radiation absorption characteristics and formed with an internal chamber, said housing having exterior portions thereof flanking said chamber and hollowed out for providing shallow cavities therein, penetrating radiation scattering material disposed in each of said cavities, and lock tumbler means contained in said chamber, said tumbler means being made of a material having low penetrating radiation absorptioncharacteristics, said scattering material including a layer of onequarter inch steel balls.

7. A lock as defined in claim 4, said last-named material being nylon.

8. A lock protected against radiographic compromise and comprising tumbler means made or" nylon, a casing for said tumbler means, a housing made of lead contacting said casing, and layers of X-ray scattering material flanking said tumbler means and secured to said housing.

References Cited in the file of this patent UNITED STATES PATENTS OTHER REFERENCES General Electric Review of March 1939. Pages 109 to 1 13.

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