US 3895508 A
A flat key and a process for the production thereof in which a blank is cut on a copying machine to form a shank having a head with a width at most slightly exceeding the width of the shank proper, and a separate head is formed with a slot in which the head of the shank is detachably received with wedge action between separate head and the head of the shank.
Claims available in
Description (OCR text may contain errors)
United States Patent Crasnianski July 22, 1975  FLAT KEY 2,653,492 9/1953 Abrams 70/408 X 3,587,260 6 1971 T 7O 3  Inventor: Serge Crasnianski, Grenoble, 95
France  Assignee: Crasnianski France S.A., France Primary Wolfe Attorney, Agent, or Fzrm-Robert E. Burns; Flledl 1973 Emmanuel J. Lobato; Bruce L. Adams Appl. No.: 418,223
 ABSTRACT A flat key and a process for the production thereof in which a blank is cut on a copying machine to form a shank having a head with a width at most slightly exceeding the width of the shank proper, and a separate head is formed with a slot in which the head of the shank is detachably received with wedge action between separate head and the head of the shank.
5 Claims, 10 Drawing Figures SHEET PATENTED JUL 2 2 I975 FiG.9
FLAT KEY BACKGROUND TO THE INVENTION This invention relates to a flat key and to a process for its production.
Known flat keys are cut on copying machines from a blank consisting of a shank or core which is milled on the machine in accordance with the profile of a specimen key, and of a head whose shape varies according to the lock manufacturer and which can be round, triangular. octogonal, rectangular, etc., this head comprising a hole for fastening the key to a ring, a key board or a hook. In general, lock manufacturers make their keys for one and the same type of lock with the same blank for the shank, although keys differing in the shape of their heads can be used for one and the same type of lock. Accordingly, manufacturers concerned with the production of replacement keys and specialising in copying keys from specimens presented to them are faced with the need to stock a large number of blanks in order to be able to reproduce the flat keys for every type of lock, this stock being further multiplied for commerical reasons by a certain number of decorative finishes for one and the same type of blank, namely nickel finishes, gold finishes or various coloured finishes. For example, if the locksmith has to keep a stock of N types of key to meet the requirements of his customers, he has to multiply this stock by n different decorative finishes.
Flat keys are already known which consist of two rigidly assembled parts, namely a shank having a head substantially equal in width to the shank, and an operating head which can assume any one of a number of external forms. The main advantage of manufacturing flat keys in this way is that it is possible for the operating heads to be made of an optionally castable material or of a material sufficiently soft to be able readily to receive impressions corresponding to the necessary references and marks or even decorative patterns (key heads in the form of medals, old or new coins, etc.), which gives rise to difficulties in the case ofa key blank cut in one piece from sheet steel. In addition, it is possible, by making separate operating heads of plastics materials, to produce these heads in different colours.
In contrast, if as has hitherto been proposed, the keys have separate metal heads welded or crimped on to the shank, or plastics heads mounted on the end of the key blank, the shank or blank can only be assembled with the head in a factory and not by the locksmith or the key cutter who does not have the special machinery or equipment required. Accordingly, locksmiths and key cutters have to keep a large variety of blanks in stock. An object of this invention is to obviate this disadvantage.
BRIEF SUMMARY OF THE INVENTION The flat key according to the invention, consisting of two rigidly assembled parts, is distinguished by the fact that the head of the key shank is wedge-shaped with a very gradual taper, and by the fact that the separate head comprises a slot of corresponding shape into which the head of the shank is fitted.
Accordingly, the key according to the invention can readily be assembled by the locksmith or key cutter without any need for special equipment. In addition, the key assembly, although perfectly rigid, can also be readily taken apart so that it is possible for example to change the shank of the key without changing the head which can be of advantage in cases where locks are changed, when moving house or when changing vehicles. Finally, the blank manufacturer can limit the number of specimens in stock to that of the types of key available on the market without having to make any allowances for the shape of the key heads.
FURTHER FEATURES OF THE INVENTION In one preferred embodiment of the invention, key manfucature can be standardized even further through the production of separate operating heads which can be adapted to fit any flat key blanks irrespective in particular of their width. In this embodiment of the invention, the wedge-shaped head of the key shank is itself in the form of a separate intermediate component which externally is wedge-shaped and which, in at least one of its faces, comprises a groove with parallel edges in which is engaged the end of a shank of uniform width.
It will be appreciated that, under these circumstances, it is sufficient to keep in stock several specimens of inexpensive intermediate components all of which have the same shape and the same external dimensions and in which only the width of the grooves is different, with the result that standardized heads comprising the same slot can be fitted to shanks differing in width and profile.
According to another aspect of the invention, this intermediate wedge-shaped component has an end which projects beyond the separate head and which forms the stop of the key. By virtue of this feature, it is possible furtherto simplify the shape of the blanks which can have parallel edges over their entire length and which, for this reason, can be manufactured not only by stamping a sheet of steel, but also be drawing or extrusion which reduces their manufacturing costs.
BRIEF DESCRIPTION OF DRAWINGS Embodiments of the invention are described by way of example in the following with reference to the accompanying drawings, wherein:
FIGS. 1 to 5 are plan views showingvarious specimen blanks with standardized heads;
FIG. 6 is a plan view showing a key finished in accordance withthe invention with its separate head, whilst FIG. 7 is a view of the top edge of this head;
FIG. 8 is a plan view showing another variant of the key with a separate head; and
FIGS. 9 and 10 are, respectively, a side elevation of and a cross-section through another embodiment of the invention.
DESCRIPTION OF EMBODIMENTS As shown in FIGS. 1 to 5, the blanks of flat keys whose shanks l, 2, 3, 4, 5 differ in shape and size, with or without a lateral milled groove, all have a head 6 of standard length and width. The lateral edges 7, 7' of these heads 6 converge slightly upwards so as to form a wedge with a gradual taper. Near their ends, these standard heads 6 comprise a hole 8 designed to fasten the finished key to a key ring or key board.
FIG. 6 shows a finished key whose shank 9 has been milled to the required profile along its edge 10 and fitted with a separate operating head 11. FIG. 6 shows in dotted lines the wedge-shaped slot 12 which is formed inside the head and into which the standard head 13 of the shank with its hole 14 is fitted near its end projecting slightly beyond the head 11. On either side of the slot 12, the upper edge of the separate head 11 com prises two semi-circular notches 15, (FIG. 7) coinciding with the inner semi-circumference of the hole 14.
In the embodiment shown in FIG. 8, the integral head of the shank 9 of the blank does not project beyond the upper edge of the separate head 11 which itself has a hole 16 coinciding in the fully fitted position of the shank 9 with the hole 14 in the shank 9. In this case. a hollow rivet 19 of anodised aluminium or brass is used to assemble the separate head and the blank.
As mentioned earlier on, the separate heads of the lays shown in the drawings can be cast with their slot although as shown in FIG. 7.they can also be made of two identical parts 17, 17' each formed in their inner face with a groove 18, 18 which by superposition, form the slot 12, the two identical parts l7, 17 of the separate head being assembled either by bonding or by means of a hollow rivet, ie by means that can readily be used by unskilled personnel.
A recess formed in the surface of the head 11 opposite to that designed to receive the mark of the manufacturer or even a decorative motif, receives an adhesive label which can be used for publicity purposes by the locksmith reproducing the key.
The required profile of the shank of the blank can of course be reproduced by milling on a suitable copying machine both before and after the shank of the blank has been assembled with the separate head.
In the embodiment shown in FIGS. 9 and 10, the key according to the invention consists of a shank 20 which is obtained by drawing or extrusion and, which has parallel edges. The rear end 21 of this shank is engaged in a groove 22 with parallel edges formed in a part 23 which externally is wedge-shaped and at whose end a hole 24 is drilled. At least one of the edges of the groove 22 is formed with aprojection 25 engaging in a notch 26 formed in the corresponding edge of the shank 20 so as to lock the shank in the longitudinal direction. The part wedged with the end 21 of the shank 20 engaged therein is itself fitted in a slot 27 formed as described earlier on in the separate operating head 28 which itself can be made in one piece, for example, cast from ZAMAK or from a plastics material, or in two parts joined together by bonding. The front edge 29 of the intermediate part 23 which projects beyond the separate head 28 forms the stop for positioning the key in the lock.
The groove 22 in the intermediate component 23 can be open on the two faces of the component 23 or, as shown in FIG. 10, it can have a base whose shape, as seen in cross-section, is complementary to the profile of the cross-section of the shank 20.
As in an embodiment described above, the separate head 28 is formed in its upper edge with a semi-circular notch 30 coinciding with the inner semi-circumference of the hole 24 of the shank 20.
In addition to the advantages of the embodiments described above with reference to FIGS. 1 to 8, the improvement which has just been described enables a standard separate head to be used for any type of flat key irrespective of its width and profile, because it is sufficient to produce the intermediate components identical in shape and external dimensions which fit the slot in the separate head and in which only the groove is different according to the type of shank.
1. A flat key, comprising;
a shank which comprises, a flat and narrow profile section, and a substantially similarly flat and narrow shank head, said shank head slightly tapering toward an end thereof remove from the profile section; and
a key head surrounding the shank head, the key head being thicker and wider than the shank head, with an aperture extending through the key head and slightly tapering to fit the slightly tapering shank head with wedge action between said heads;
whereby said heads are interconnected tightly without employment of crimped or welded portions of the shank or key head.
2. A flat key according to claim 1 wherein said end of the shank head protrudes beyond an adjacent edge of the key head, enabling the shank to be readily disconnected from the key head without employment of special tools.
3. A flat key according to claim 2 wherein the key head has a semicircular notch centrally in said upper edge, the shank head having a circular opening, with a semi-circumferential part of the opening coinciding with said semi-circular notch.
4. A stock of materials for flat keys, comprising;
a supply of flat and narrow key blanks, each having a profile section for incorporation of a distinctive key profile therein.each blank having a blank head at one end of its profile section, and each blank head having a slight taper, uniform with a taper of the other blank heads of the supply, toward an end of the respective blank remote from the respective profile section; and
, a supply of key heads, each being thicker and wider than the key blanks, each having generally flat side surfaces, and each having an aperture extending through the key head between said side surfaces thereof, said aperture of each key head having a slight taper uniform with the taper of the blank heads;
thereby enabling each key blank of the supply of such blanks to be wedged into any key head of the supply of the latter heads.
5. A stock of materials according to claim 4, in which all of said blank heads have uniform length and all of said apertures of the key heads are less long than said blank heads, whereby each blank head, when wedged into the aperture of a respective key head, protrudes beyond an edge of the respective key head remote from the respective profile section; thereby enabling each key blank, wedged into a respective key head, to be readily disconnected therefrom.