US 2750902 A
Description (OCR text may contain errors)
June 19, 1956 E. MCCLELLAN 2,750,902
SAFE CONSTRUCTION Filed Aug. 16, 1954 //2 Men for United States Patent SAFE CONSTRUCTION Ralph E. McClellan, Toledo, Ohio, assignor. to Meilink Steel Safe Co., Toledo, Ohio, a corporation of Ohio Application August 16, 1954, Serial No. 449,904
1 Claim. (Cl. 109-81) This invention relates to wall and safe features resistant to attack, especially in the guarding of contents against unwarranted attack.
This invention has utility when incorporated in an inter wall of drill resistant properties, say of hard metal and alloys with the outer face of such wall configured not to have symmetrical cutting arc, thereby detracting from hard steel drill heating or fusion action. This results in discontinuous grabbing at wall different regions as spaced, with torque strains of such effectiveness as to break the tool.
Referring to the drawings:
Fig. l is a fragmentary horizontal section at the left hand corner of a one door safe, having features of the invention incorporated therein;
Fig. 2 is a sectional showing of a couple of ribs of the special face providing wall, with dotted line-showing of unsymmetrical drill approach thereto;
Fig. 3 is a sectional showing of such wall face of general sinuous contour, with adjacent ribs of different arc radii;
Fig. 4 is a section thru adjacently dissimilar diameter cylindrical rods in abutting weld assembly, wherein the adjacent faces as rising from the root do not have the same are;
Fig. 5 is a section of the protective face wall, enlarged from its showing in the safe wall as extending inward from the door opening in Fig. 1;
Fig. 6 is a fragmentary showing of the protective wall face with the adjacent pointed ribs, one more blunt than the other, instead of lop-sided as is the showing in Fig. 5;
Fig. 7 is a protective wall face showing of straight faced cones and concave faced cones spacing the straight faced cones;
Fig. 8 is a showing of a wall face of rectangular pyramids which alternately differing in side wall pitch; and
Fig. 9 is a fragmentary wall section of successive domes, the intermediate domes of lesser diameter having ogee arc sections toward their bases.
A safe body outer wall 1 encloses a filler or insulation 2. An inner wall 3 provides therein a safe interior 4. At a front opening 5 is a door having an outside front wall 6, an inner wall 7 and a stepped connecting frame 8 registering with a door jamb 9 connecting the wall 1 with the wall 3. Combination lock spindle 10 is on the door front for operating a lock 11 so that a handle 12 may throw lock-released bolt mechanism 13, thus to clear the structure for outswinging of the door. Insulation filler 2 inside the safe door front wall 6 is clear of the lock 11 and the bolt mechanism due to a pan or interwall diaphragm 14.
Rivets 15 have clearance at openings 16 to mount a zigzag protective face structure 17. This face 17 on its side outward toward the wall 6 has depressed regions, herein shown as V-bottomed grooves or valleys 18 forming root portions from opposite sides of which rise projecting region limits as the termini of diverging face portions 19, 20, at different angles or pitches. In practice While there is adequate range to carry-thru these details of protective value, it is believed in point to direct attention to the fact that diameter drill is normally maximum for the tool for which the point 23 may be an obtuse angle of about 116 or have a cutting edge less than about 35 with the plane of the plate or protective face structure 17. Considering the drill to be of hard steel, driven at two hundred even up to five hundred revolutions per minute, and pressure exerted for the tool to enter the work, there is heat developed from the frictional contact to heat the metal for films therefrom to be annealed and scraped off in drill progress. This is on the basis that the work to be drilled is hard.
Should the material to be drilled be soft, this type of hard steel drill will act upon the relatively soft metal for producing chips which adhere by weld action on the drill tip and cutting edges, thus nullifying its cutting action. However, here the protective wall selection is that such wall, at least as to its face as outward from the safe interior, be heat treated, or the body he of hard stock. Accordingly, there is a hardness wall in a range to require efficient operation thereupon of carbide and such range of hard steel type of material in drills. Such may range of Rockwell hardness A 82 to 94 and higher and extend into the not so hard Rockwell scale C 61 to 64. This means that the protective wall face, as spaced inward from the safe outer wall, does not afford a continuous contact area or closed figure face distributed as endless about the drill tip. The high speed rotation, together with the applied pressure, cause the drill tip to develop, from such unbalanced resistance, lateral pushings or wedge actions. The fact that the rivets 15 allow the protective plate 17 to shift or float, thus nullify lateral holding of the work to center with the drill. Supplementing this disturbance of cutting action are the interruptions or successive grabbings of such unbalanced resistances for taking on bites at the stock. As the drill comes against a bite region from a clearway or gap, there is impedance acting as a torque hammer reverse tending to twist the tool in its body, counter to its direction of rotation. These poundings or hammerings not only tend to introduce internal crystallization, but actually rapidly develop drill rupture. The drill is thus soon disabled. Unauthorized access to the lock or boltwork is not achieved when there is concealed in the safe structure discontinuous dissimilar face regions defeating drill entrance for peripheral cutting action endless orbits.
Various embodiments have to do with rendering effective nullification of drill operation. Economy in manufacture of the special face may be taken into account by differing angle adjacent rib faces in an embedded irregular corrugation body 17 (Fig. 2). In lieu of apex providing or linear ribs, there may be sinuous contour of major rib 26 as to adjacent minor radius rib 27 (Fig. 3) from a common root or re-entrant region or groove 28.
Weld connected rods 29, 30 (Fig. 4), are shown as even having plural depth root regions 31, 32. As with the fiat faces (Fig. 2) and the arc faces (Fig. 3), there is dissimilar divergence of the faces as outward from the re-entrant limit.
Stock having flat side 33 (Fig. 5) has such not outward, but on the face toward the outer wall 1 (Fig. 1) has groove depth lines or roots 34, with dissimilar rise angle flat faces 35, 36, therefrom. Inner wall 3 is shown with a tongue 37 pushed out therefrom and overlapping an edge of the wall 33, 34, 35, 36 (Fig. 1) thereby providing a fastening loose in lieu of the rivet feature for locating the wall 17.
As a departure from the dissimilar slant divergent faces 35, 36 (Fig. embodiment as Wider base ribs spaced by ribs more narrow (Fig. 6) are here shown as from a planar back 37, a root 38, steeper flat faces 39 and less slant faces 40.
Departure from the rib and groove embodiments is in rows of cones 41, 42, alternating with each other in the two directions and rising from fiat base 43. From roots 44 straight face cone 41 sides take difierent ascent from the dissimilar concave face side cones 42 (Fig. 7).
Interrupted or discontinuous peaks or points are provided by rectangular base pyramids 45, 46, from a base 47, providing roots 48. The straight sides of the cones 46 are more steep than the sides of the cones 45 (Fig. 8).
A base 49 (Fig. 9) has domes 50 spaced by less diameter domes 51 having ogee mergings to spacing regions, valleys or roots 52.
The protective wall or safe structure as herein disclosed is an embedded ply with the outward face portion of greater area than like dimension section of the enclos ing wall as directly outward therefrom. The area surplusage of this face is development achieved by root depth regions and dissimilar diverging faces rising therefrom linear or point projecting regions spaced by the irregular depth connecting regions. In practice this means that a rotary drill theretoward, when thrust to engage a pair of diametrical regions for tangency with two faces and gap or clearance spacings between said tangency regions, defines a plane. As there be drill pressure to act on the protective wall face, should there be attack at each tangency, the dissimilar characteristic insures that such attacks are of cutting arc departure, with differing peripheral resistance to the functioning of the drill. The drill torque is unsymmetrical twistings overcoming the physical or hold-together properties of the tool, with resultant tool rupture almost at once there is drillingattack on the ribbed or pimpled face.
Stock as superficially hardened, may have the interior thereof of toughness to resist fracture or brittle traits as more prevalent in the tool, especially carbides and some alloys. Impact attack on the wall, even to the extent of developing fracture, has such wall protective.
What is claimed and it is desired to secure by Letters Patent is:
A drill resistant wall comprising a pair of relatively thin hard spaced shells with a relatively thicker and softer filler therebetween, the improvement comprising: a hardened metal plate between said shells with said filler, at least one surface of said plate being irregular and having a plurality of alternate sharp projections and depressions connected by sloping surfaces having an angle of more than about 35 with the plane of said plate, said sloping surfaces between two adjacent sharp projections having different slopes to their intermediate depression, and means for fastening said plate in said wall to permit limited movement thereof in the plane of said plate.
References Cited in the file of this patent Great Britain May 19, 1941