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Publication numberUS3919920 A
Publication typeGrant
Publication dateNov 18, 1975
Filing dateOct 2, 1973
Priority dateMay 10, 1972
Publication numberUS 3919920 A, US 3919920A, US-A-3919920, US3919920 A, US3919920A
InventorsSchlage Ernest L
Original AssigneeSchlage Lock Co
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Machine for making obtunded key profile
US 3919920 A
An obtunded key profile is provided in a lock key having a shank extending parallel to a straight reference line. The key has a plurality of reference surfaces spaced apart longitudinally in the direction of the line according to a predetermined pattern and spaced transversely away from the line also according to a predetermined pattern. An adjacent pair of the reference surfaces is joined by a connecting surface devoid of a sharp peak.
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Description  (OCR text may contain errors)

[ 1 Nov. 18, 1975 l l MACHINE FOR MAKING OBTUNDED KEY PROFILE [75] Inventor: Ernest L. Schlage, Burlingame,


[73] Assignee: Schlage Lock Company, San

Francisco, Calif.

1221 Filed: on. 2, 1973 21 1 Appl. No.: 402,738

Related US. Application Data [62] Division of Ser. No. 252,344, May 10. 1972.

UNITED STATES PATENTS 969,702 9/1910 Johnson 90/1305 1,135,676 4/1915 Engelhert.... 90/1305 2,098,728 1 1/1'937 McPhee 90/1305 2.129.883 9/1938 Stull 90/1305 R26.848 4/1970 Simon 90/1305 Primary Etaminer-Frank T. Yost Assistant E.\'un1inerZ. R. Bilinsky Attorney, Agent, 01' Firn1Lothrop & West [57] ABSTRACT An obtunded key profile is provided in a lock key having a shank extending parallel to a straight reference line. The key has a plurality of reference surfaces spaced apart longitudinally in the direction of the line according to a predetermined pattern and spaced transversely away from the line also according to a predetermined pattern. An adjacent pair of the reference surfaces is joined by a connecting surface devoid of a sharp peak.

A machine for providing an obtunded key profile in a lock key having a shank includes a base on which a pillow block is mounted. A stylus projects from the pillow block. A shaft is rotatable in the pillow block and carries a key cutter. Mounted to move on the base in two normal directions in a plane containing the shaft axis is a carriage having a key blank holder. A key blank in the holder is cut by the cutter according to contact with the stylus of depth gauge rods settably secured on the carriage. The stylus, the depth gauge rods, or both, are devoid of sharp peaks.

2 Claims, 7 Drawing Figures U.S. Patent Nov. 18,1975 Sheet20f2 3,919,920

Fllllli *n uv rll lm MACHINE FOR MAKING OBTUNDED KEY PROFILE This is a division application Ser. No. 252,344, filed, May 10, 1972 and now abandoned.

Many key blanks for use in locksets having tumblers are serrated, dentated or toothed since they are provided along at least one edge with notches defined by truncated V-shaped surface. The intersection of the surfaces near the edge of the key affords sharp peaks. These peaks produce numerous operational difficulties.

It is therefore an object of my invention to provide an improved configuration of the serrated, dentated or toothed portion of a lock cylinder key.

It is another object of my invention to provide an improved, obtunded configuration for key blades or shanks of various shapes and cross-sections, such as flat, corrugated, rectangular, T-shaped, V"-shaped, dendritic or cruciform.

It is another object of my invention to provide an improved, obtunded configuration for keys notched along one edge or along two edges, as in reversible keys.

A further object of my invention is to provide an improved, obtunded configuration for keys designed for use in pin tumbler cylinders or wafer tumbler cylinders, whether the pin tumblers are circular cylindrical or are other than circular in cross-section, such as square, and whether the pin ends have conical ends, bullet-nose ends or wedge-shaped ends, or are supplemented by bearing balls, and whether the wafer tumblers have dogging projections extending from one or both ends.

A further object of the invention is to provide an improved, obtunded configuration for keys of any length, particularly keys for four, five, six or seven rows of tumblers in the cylinder.

An additional object of the invention is to provide an improved, obtunded configuration to prevent the key peaks from producing, oscillations of the tumbler pins in an excessive amout during key insertion and retraction, thereby causing pin wear, spring fatigue and high key camming forces.

A still further object of the invention is to provide an improved, obtunded configuration to prevent the key peaks from promoting improper opening by false or bogus keys, either by partial key insertion, by a slow insertion or retraction of the key, or by a rapid insertion and retraction of the key causing the tumblers to bounce in their chambers similar to the effect caused by raking picks or lock picking vibrators.

An additional object of the invention is to provide a machine for cutting a key to meet the various objects of the invention.

A still further object of the invention is to provide a machine for cutting keys pursuant to the invention and that can be adapted to cut keys automatically to meet the various objects of the invention.

Other objects together with the foregoing are attained in the embodiments of the invention described in the accompanying description and illustrated in the accompanying drawings, in which:

FIG. 1 is an elevation of one form of an obtunded key pursuant to my invention;

FIG. 2 is an elevation of another form of contour of an obtunded key pursuant to my invention;

FIG. 3 is an elevation of a further form of contour of an obtunded key pursuant to my invention;

FIG. 4 is an elevation of still further form of contour of an obtunded key pursuant to my invention;

FIG. 5 is an elevation of an additional form of contour of an obtunded key pursuant to my invention;

FIG. 6 is a plan, partly diagrammatic, of my machine for forming an obtunded key; and

FIG. 7 is a plan showing a detail of a modification of my machine as shown in FIG. 6.

As an example of a key blank configured pursuant to the invention, there is illustrated in FIG. 1 a generally flat, stiff blank having a shank 6 and having a bow portion 7 for manual operation, the bow being broken away to reduce the size of the figure. The shank 6 along one edge 8 is initially substantially rectilinear. This edge or a substantially coincident, imaginary, parallel line 9 can be utilized as a reference or datum line. At its end opposite the bow 7 the key shank is provided with a rounded nose ll merging with inclined sides 12 and 13 to assist the key in entering the lock mechanism. The key, in this instance, is preferably designed for use in a lock having five columns of tumblers to be actuated, each of the columns being represented by a respective one of five broken lines 15, l6, 17, 18 and 19. These lines are appropriately spaced in a longitudinal direction from one of two opposite, transverse datum surfaces 21 and 22 at the junction of the key shank with the key bow. The lines 15 to 19, inclusive, thus are arranged according to a predetermined pattern and can be considered to denote stations spaced apart longitudinally of the key in set or predetermined amounts to serve a particular lock.

To meet the needs of the lock with which the key is to be utilized it is also desired to provide at each of the stations or locations 15 to 19, inclusive, a datum surface that is disposed a predetermined distance and according to a predetermined pattern from either the imaginary, straight reference line 9 or from the edge 8, if that happens to be an appropriate reference. The pattern of the datum surfaces is often indicated on the key bow by a series of numerals 24, the exemplary number in this instance being 35487. This indicates that at the station or line 15, for example, there is a datum surface 26 spaced from the imaginary line 9 a lateral or transverse distance of three units. Comparably, at the line or station 16 there is provided a datum surface 27 spaced from the line 9 a transverse or lateral distance of five units, and at the location 17 there is provided a datum surface 28 spaced from the line 9 a lateral distance of four units. At the location or station 18 the datum surface 29 is laterally spaced from the datum line 9 a distance of eight units and, finally, at the location 19 the datum surface 30 is spaced transversely from the datum line 9 a distance of seven units. Each of the datum surfaces 26 to 30, inclusive, is intended to abut a tumbler pin or wafer in the lock. For that reason, and depending upon the shape of the coacting parts, the surface, such as 26, can be a mathematical line ex tending across the thickness of the key and constituting a point when seen in FIG. 1. However, the usual key followers or pins have some dimension larger than that of a point, and hence it is preferred to have the surface 26 extend in a direction parallel to the imaginary line 9 for a preselected longitudinal distance; for example, 0.031 inches.

To establish the flat datum surface 26 in the desired location, it is customary to shape the key blank by a cutter bounded in part by a pair of converging cutting surfaces indicated by the broken lines 32 and 33. These surfaces, in one instance, are disposed at one hundred degrees included angle and instead of converging to a point are truncated to afford the surface width of 0.03 l inches in a direction normal to the location line and parallel to the line 9. When the cutter operates in coincidence with the line 16, it produces a similar, flat datum surface 27. The locations of the comparable cutter lines 32 and 33a result in the formation of a peak 34, because the lines 33a and 32 intersect at a sharp point. Similarly, when the surface 28 is made, the cutter lines 32a and 33b produce a similar peak 36. Additional peaks such as 37, 38 and 39 are comparably formed. The cutterin each instance is moved into its longitudinal position symmetrical with the location lines l5, 16, 17, 18 and 19 and ther is moved from the datum line 9 laterally or transversely into its final cutting position. This produces the describedpeaks.

Pursuant to my invention and as illustrated in FIG. 1, thecutter is differentlyoperated to produce my obtunded or obtruncated key profile. If the cutter is the usual rotary cutter rotatable about an axis parallel to the imaginary-line-9, the cutter is moved into symmetry with the line 15 and then is moved laterally to produce the truncated V notch with a first surface 26. Instead of being transversely withdrawn and then moved longitudinallyaccording. to rectangular coordinates to the next location 16, the rotary cutter is moved as soon as the surface 26 has been formed. This provides a rectilinear, longitudinal surface 41 that is, in effect, a continuation of the surface 26. When the cutter is indexed and moved into the position of the line 16 to produce the surface 27, no peak 34 results, as such peak has been obtunded.

In a comparable fashion, when the surface 27 has been provided, the cutter islaterally backed off even with thesurface 28 and is then moved longitudinally to provide side surfaces 42 and 43, in the process also establishing the surface 28. The peaks 36 and 37 are obtunded. Finally, after the surface 29 has been established, the cutter is moved to the transverse location of the surface 30 and then is moved longitudinally to provide not only the surface 30 but also the surfaces 44 and 46, virtual extensions of the surface 30, and thereby obtunding the peaks 38 and 39. By this rectangular profile method. all of the usual peaks are eliminated from the key profile.

Special consideration must be given to keys with a continually, descending profile; for example, 34578. When fully obtunded such a key has no peaks to be caught behind pins blocked when the cylinder plug is turned. Hence the key can always be withdrawn even though the plug is not in the customary position for key withdrawal. Keys of this descending or downhill character make up but a small part of the total possible key combinations and so, in most cases, can be eliminated entirely. If this is not feasible, at least one uphill surface (not necessarily sharply peaked) can be provided to preclude improper withdrawal of keys having a downhill profile.

As shown in FIG. 2, the key shank 6 is the same as before, having the same code number 24, and having the same surfaces 26, 27,28, 29 and 30. The key is formed by a cutter represented by the broken lines 32 and 33, as before. The cutter moves longitudinally to the first station 15 and moves laterally to the desired depth for the suface 26. The .cutter then moves longitudinally just to the edge of or clear of the flat surface 26 .and then moves to the surface 27symmetrical with the station l6 by moving on a path 51 not parallel to but inclined with respect to the line 9. The path 51' is a straight line at the particular angle making a minimum distance between the closest edges of the surfaces'26 and 27. That is, the surface 51 is the shortest path between the adjacent edges of the two surfaces 26 and 27. The cutter is moved to the next station 17 on an inclinedv path 52 generating an edge of minimum extent between the edges of the flat surface 27 and the beginning. of the nextadjacent flat surface 28. In moving to the surface 29, the cutter does so along a minimum path 53 at a relatively steep inclination between the edges of the flats. From the surface 29 the cutter moves along a minimum, inclined path 54 between the flat edges and, finally, from the surface 30 the cutter moves along a short, peakless path 56 to the angle surface 12 of the key shank. Each of the surfaces 51, 52, 53, 54 and 56 obtunds the otherwise present key peaks 34, 36, 37, 38

and 39.

As particularly shown in FIG. 3, the key shank 6 is as before with the same configuration numeral 24 and is established by the same cutter represented by the broken lines 32 and 33 with respect to the same datum line 9. At the station 15 the cutter isoperated just as before to provide the surface 26, but in moving from station 15 to station 16 in order to provide the surface 27 the cutter moves in an arbitrary, curved path 57. The path contour is selected to afford the desired movement of the following tumbler during key insertion or retraction, to provide adequate material between the surfaces 26 and 27 and to afford whatever accelerations between stations are deemed advantageous. Similarly, the cutter moves from the surface 27 to the station 17 to form the surface 28 and thence to the station 18 to form the surface 29, then to the station 19 to form the surface 30, and finally to the end surface 12. In each instance the resulting curve surfaces 57, 58, 59,60 and 61, although arbitrary, leave the key devoid of otherwise present peaks such as 34, 36, 37, 38 and 39.

.As particularlyshown in FIG. 4, the key shank 6 therein has the same configuration index 24 as before and has the same datum surfaces 26, 27, 28, 29 and 30 disposed at the same respective stations 15, 16, l7, l8 and 19. Furthermore, the same cutter indicated by the broken lines 32 and 33 is employed. In this instance the cutter, although moving parallel to the datum line 9, does not move at levels coincident with the surfaces 26, 27, 28, 29 and30. Rather, the cutter, although moving according to rectangular coordinates, travels longitudinally at arbitrary levels so that from the surface 26 to the surface 27, for example, there are three surfaces 66, 67 and 68 provided. The surface 67 is parallel to the imaginary line 9 and obtunds the otherwise resulting peak34. Quite similarly, the peaks 36, 37, 38 and 39 are obtunded bythe longitudinal surfaces 69, 70, 71 and 72. In this instance while the peaks have been obtunded, material has not been removed to as great an extent as previously described. 7

In a fashion somewhat comparable to the showings in FIGS. 3 and 4, the key shank 6, in FIG. 5 has the same datum surface configuration indicated by the numeral 24, but in this instance the surface 26 at the station 15 is joined to the surface 27 at the station 16 by a circularly arcuate surface 73 which obtunds the otherwise existing peak 34. Similarly, surfaces 74, 75, 76 and 77 obtund the otherwise occurring peaks 36, 37, 38 and 39.

Various obtunded key profiles can be produced in various different ways and with various different mechanisms, but I have particularly provided a machine, as shown in FIGS. 6 and 7, especially for this purpose.

The machine includes a stationary base frame 81 on which is mounted a pillow block 82 carrying a power driven, rotary shaft 83 equipped with a rotatable milling cutter 84. Preferably, the cutter edges are inclined at a 100 included angle as indicated by the dotted lines 32 and 33. These cutting edges do not intersect, but rather merge with a central cutting edge 88 parallel to the longitudinal axis 89 of the shaft 83.

Designed to move in a plane parallel to and on the base frame 81 is a primary slide 91 having a pair of longitudinal slots 92 and 93 therein parallel to the axis 89. Guide pins 94 and 96 project from the base through the slots and have retainers 97 thereon. The primary slide 91 can move only in a longitudinal direction in one plane. Mounted on the primary slide 91 is a secondary slide 98 also movable in a parallel plane but only in a normal or transverse direction at right angles to the axis 89. The secondary slide 98 is guided by pins 99 and 101 fixed thereon and passing through transversely extending slots 103 and 104 in the primary slide 91. There are appropriate retainers (not shown) on the pins. The secondary slide 98 is confined to planar, transverse movement with respect to the primary slide 91.

The secondary slide 98 in the vicinity of the cutter 84 is provided with a key blank vise 106. This includes an extension 107 of the secondary slide 98 and a plate 108 movable toward and away therefrom under the influence of a threaded shaft 109 rotated by a vise handle 111. A key bland 112 can be introduced between the secondary slide extension 107 and the plate 108 with its edge 113 (or the datum line 9) parallel to the axis 89. The blank is clamped in position with a datum surface 22 of the key blank abutting the near one of a pair of suitable stops 114 and 115 projecting upwardly from the secondary slide 98 through apertures 116 and 117 in the vise plate 108, so that the key is properly positioned and secured. A handle 118 on the secondary slide 98 permits the operator to move the key blank longitudinally, transversely and in any single plane combination of longitudinal and transverse paths with respect to the cutter 84, so that any configuration can be given to the edge 113 of the blank.

In accordance with the invention and to provide any of the desired obtunded key profiles, I preferably lodge in the secondary carriage 98 a plurality of depth gauge rods 121, 122, 123, 124 and 125 corresponding in number and in longitudinal stations to the lines to 19, inclusive. Each depth gauge rod is provided with a rectangular end 127 and likewise carries a plurality of indicia 128 corresponding to the various possible depths or transverse distances from the line 9 of the key profile intended or of the datum surfaces. There is a stop block 129 on the secondary carriage 98. Depth gauge rods can be variably positioned with selected ones of their respective numerals indexed against the edge 131 of the secondary carriage. They are held in set or adjusted position by a depth gauge clamp 132 screwed into the carriage to force the various depth gauge rods against each other. The rods either are of 6 appropriate width or have intervening spacers, so that they maintain the proper longitudinal spacing.

To cooperate with the depth gauge rods so provided, there is mounted on the pillow block 82 a stylus 133 that has a longitudinally extending surface 134, including inclined side faces, thereon designed to abut against the end surface 127 of whatever depth gauge rod happens to be immediately opposite.

In the operation of this device, the various depth gauge rods are set with an indicated reading similar to that on the key and are then clamped. The operator then moves the primary and secondary carriages simultaneously in any desired path so that the stylus 133 has its surface 134 abutted by successive ends of the depth gauge rods. This produces the various datum surfaces 26, 27, 28, 29 and 30 on the key blank. The operator by moving the primary and secondary carriages appropriately with respect to the stylus 133 can guide the cutter to produce any of the obtunded profiles described in FIGS. 1-5, inclusive, and more. When the key blank has been so configured, the handle 111 is released and the key blank is removed from the vise. The key blank so configured can subsequently be utilized as a pattern in a standard key cutting machine of the sort in which the cutter formulating a new blank is made to follow the profile of a sample or pattern key appropriately kept in position.

While the cutter 84 is usually used, I sometimes prefer a higher speed cutter rotating around a perpendicular axis. As shown in FIG. 7, a high speed gear housing 136 contains a skew driving gear 137 on the end of the shaft 83. Meshing with the gear 137 is a skew driven gear 138 on the shaft 139 of a cutter 141 of very small diameter. This cutter 141 is made to cut the key blank in the manner previously described and does the same kind of job, except that it leaves small radius curves where sharp intersections would otherwise be.

What is claimed is:

1. A machine for cutting an obtunded key from a key blank, comprising a base, means supporting a key cutter for rotation on said base about an axis, a stylus fixed on said base in a plane parallel to said axis and having a longitudinal face and inclined side faces tranverse to said plane, a carriage, means mounting said carriage on said base for universal movement in a plane to said axis, a key blank holder on said carriage adjacent said key cutter, a plurality of elongated depth gauge rods having end surfaces and arranged in parallel, side by side relation with said rods extending toward said axis and adjacent said stylus said stylus and said rods being coplanar, and means mounting said depth gauge rods for individual adjustment on said carriage toward and away from said axis whereby movement of said carriage toward and along said axis causes said end surfaces of the gauge rods to engage and move along said longitudinal and inclined side faces of said stylus and simultaneously causes said key cutter to cut an obtunded key from a key blank held in said key blank holder.

2. A machine as in claim 1 in which said stylus is relatively wide and said rods are positioned so that said stylus can engage two of said rods simultaneously.

Patent Citations
Cited PatentFiling datePublication dateApplicantTitle
US969702 *Mar 10, 1910Sep 6, 1910Corbin Cabinet Lock CompanyKey-cutting machine.
US1135676 *Apr 13, 1915 Key-cutting machine.
US2098728 *Jan 27, 1936Nov 9, 1937Seth A McpheeKey cutting machine
US2129883 *Oct 10, 1935Sep 13, 1938Western Electric CoMaterial working apparatus
Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US4022107 *Jan 8, 1976May 10, 1977Fort Lock CorporationTubular key cutting machine
US4188163 *Jul 21, 1978Feb 12, 1980John JuskevicKey duplicating machine
US4256423 *Aug 13, 1979Mar 17, 1981John JuskevicKey cutting machine
US4526498 *Jul 20, 1982Jul 2, 1985Lloyd Matheson, Inc.Key forming machine
US4646590 *Nov 21, 1985Mar 3, 1987Jones Brian WTemporary key template
US5146689 *Jan 29, 1992Sep 15, 1992Maromatic Company, Inc.Key reading method and apparatus
US5271698 *Sep 30, 1991Dec 21, 1993Axxess Entry TechnologiesKey cutting machine with a code selectable key duplicating system
US5908273 *Jul 31, 1997Jun 1, 1999Machine Magic-LlcKey duplication apparatus and method
US5951218 *Feb 20, 1998Sep 14, 1999Wu; Kuo-ShenKey duplicating machine
US6152662 *Jul 24, 1998Nov 28, 2000Machine Magic, LlcKey duplication apparatus and method
US6406227Feb 1, 2000Jun 18, 2002Machine Magic LlcKey measurement apparatus and method
DE2850813A1 *Nov 23, 1978Jun 7, 1979Kis France SaVorrichtung zum bearbeiten von schluesseln und verfahren zur benutzung der vorrichtung
EP0103499A1 *Aug 3, 1983Mar 21, 1984Société Anonyme H.K. FRANCEApparatus for duplicating coded keys
EP0133091A1 *Jul 10, 1984Feb 13, 1985Société Anonyme H.K. FRANCEMethod of producing a key with a known number or code, and machine for carrying out this method
U.S. Classification409/82
International ClassificationB23C3/35, B23C3/00
Cooperative ClassificationB23C3/355
European ClassificationB23C3/35B