Key blank
United States Patent 2065294

The central problem in key servicing is the provision of a maximum number of changes from the minimum number of key blanks. Such changes have ordinarily been those obtainable 6 from a variance in the number of, depth and spacing of the notches by which tumblers are controlled. The combination...

Reuben, Simon
Application Number:
Publication Date:
Filing Date:
Reuben, Simon
Primary Class:
Other Classes:
70/402, 70/406
International Classes:
E05B19/00; E05B19/10
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The central problem in key servicing is the provision of a maximum number of changes from the minimum number of key blanks. Such changes have ordinarily been those obtainable 6 from a variance in the number of, depth and spacing of the notches by which tumblers are controlled. The combination for a particular lock has been "coded" and service agencies have been provided with the codes for all makes and models of locks for which they might be required to cut keys. Manufacturers of locks have had such latitude as might be afforded by the variables indicated brought together in differing combinations. It has been proposed as an expedient, in some instances, to vary the shoulders by which key penetration is determined and, thereby, afford a variation in key structures for identical combinations.

It is the principal object of the present invention to provide an improved key blank structure in which the so-called changes are determined for a lock of a given combination by the location of the shoulder on one or both edges of the finished key. More particularly, the principal object of the invention is to associate with a key blank suitable indicia by whch even an unskilled mechanic might locate the shoulders on one or both edges of a key blank in accordance with the requirements for the particular lock to be fitted, and wholly independently of the particular combination of such lock. In accordance with the invention the usual changes to be effected in the combination through the character, number and location of the notches are not availed of as the only way to accomplish variety but, on the contrary, for a given combination reliance is placed on a change of the shoulder location by which the penetration of the key for a particular lock is more or less and this penetration made the determining factor. Thus, the number of changes possible are directly proportional to the number of shoulder locations provided.

A further object of the invention is to incorporate in a key blank indicia by which the key maker may be guided in providing shoulders in proper locations for the particular lock to be fitted.

The invention will be described more particularly in connection with the illustrative embodiments shown in the accompanying drawing, wherein: Figure 1 is a view in side elevation of a key made for use with a lock of a particular combination from a blank embodying the present improvements and susceptible of alteration to effect changes for the particular lock through variance in the shoulder location.

Figure 2 is a view showing the bottom edge of the key illustrated in Figure 1, it being understood that the top edge may bear similar indicia. Figures 3-6 are other views of a key blank showing different shoulder locations provided in accordance with the improved indicia, it being assumed that the keys are to be used with locks of the same combination. Figure 7 is a longitudinal section through a cylinder lock showing somewhat schematically the relationship of the key thereto and the control of its penetration by the shoulder locations.

One problem solved by the present improvements will illustrate the difficulties now suffered by vendors, users and servicing agencies for locks when it is stated that it is the practice to provide locks of varying combinations for each car manufactured, even though the car may bear as many as four locks. This imposes on the vendor the necessity of manufacturing locks of four differing combinations, on the automobile manufacturer the problem of installing the intended lock in its intended location, on the user the problem of having available and replacing any one of the four different keys, and on the servicing agent the stocking of four different blanks to meet the user's possible requirements.

In accordance with the present invention it is contemplated that under the circumstances suggested a car might be provided with four locks having identical combinations and operable by keys made from similar key blanks but inoperable by the same keys. This highly desirable condition is obtained by forming the blanks with indicia to guide the key maker in locating shoulders which determine the penetration of the key. Accordingly, even though the locks may have similar combinations the key penetration might need to be varied to operate the tumblers.

Referring now to Figure 1 the improved key blank is illustrated at a and the notches for the particular combination at a'. On the face of the blank a are provided lines, marks or other indicia indicated generally by the letters, A, B, C, D, etc. in the drawing, such letters or symbols being preferably applied in practice to the key blank. As shown in Figure 2 such indicia may be applied to the lower edge for the convenience of the key maker and may also be applied to the upper edge. It is contemplated that for any one of a number of locks having similar combinations the operation of the tumblers be dependent upon the penetration of the key and this pene- 65 tration be made dependent, in turn, upon the location of the shoulder on one or each edge.

The key maker may make or carry in stock keys adapted for operation of a lock of a particular combination and he may then, having information as to the shoulder location, cut the shoulders in accordance with the indicia provided to the various locations A, B, C, etc. on one or both edges.

Figures 3-6 show varying locations of the shoulders on both edges and it will be understood that the number of changes thus made possible will be directly proportional to the number of possible shoulder locations. In the illustrated embodiment, for instance, indicia are provided for eight shoulder locations so the possible number of changes to be accomplished in varying them is directly proportional to eight to the second power. As shown in Figure 7 the particular key has its shoulders located at C and E, the cylinder being so formed. Such a key when introduced will operate the particular combination.

By varying the shoulder locations in other cylinders similar keys may be used, except changes can be accomplished through the location of the shoulders, as is highly desirable. The invention is not to be limited to the character of the indicia itself since it will be understood that the principle underlies the inventive concept, this principle being addressed to the provision of changes through shoulder locations. I claim as my invention: 1. A key blank provided with indicia adjacent its edges to be followed in cutting shoulders to determine the key penetration in a particular lock. 2. A key blank provided on its face adjacent its edges with parallel lines disposed generally at right angles to the shank, and indicating shoulder locations to be cut according to the intended penetration of the key in the particular lock. REUBEN SIMON.