CA1051214A

CA1051214A - Key for a cylinder lock and method of manufacture

Info

Publication number: CA1051214A
Application number: CA260,927A
Authority: CA
Inventors: Heinrich Gretler
Original assignee: Bauer Kaba AG
Current assignee: Bauer Kaba AG
Priority date: 1975-01-24
Filing date: 1976-09-10
Publication date: 1979-03-27
Also published as: CH581974A5

Abstract

ABSTRACT OF THE DISCLOSURE
The present invention provides a key for a cylinder lock with recesses for the tumbler pins, wherein at least one recess of the key has at least one planar side portion adjacent to the key surface which in the longitudinal di-rection of the key is parallel to the longitudinal median plane of the recess and to the axis of the associated tum-bler pin.

Description

:lOSi214 BACKGROUND OF THE INVENTION
The invention relates to a key for a cylinder lock with recesses for the tumbler pins.
The invention also relates to a method for manufacturing the key.
In known flat keys with recesses for receiving the preferably cylindrical tumbler pins located in radially displaceable manner in the lock rotor, the recesses are drilled out of the flat sides of the key, whereby conical countersunk holes are formed on the key shank whose largest diameter on the key surface are directed towards the depth of the particular hole, i, e. the larger the step depth of the particular recess selected corresponding to the lateral permutation of the flat key, the larger the diameter, In principle a corresponding relationship between the depth and width of the key recess also exists if in order to conceal the actual position of the tumbler pins and consequently making unauthorised duplication of the key more difficult, the recesses are drawn longitudinally in the longitudinal direction of the key, i. e. are not drilled out but are instead milled into the key shank with a milling cutter of the same shape and size as the drill for the above-mentioned countersunk holes. The reason is that the largest width of a thus milled oblong recess measured on the key surface at right angles to the key shank corresponds, in the case of the same depth as for the countersunk hole to the largest diameter of the recess made as a conical countersunk hole on the key surface.
A recess made in the form of a countersunk hole takes up just

-2-as much space longitudinally and transversely relative to the key shank, although in the case of drilled recesses with larger step depths in which the cylindrical portion of the tumbler pin engaged in the recess is located below the key surface, the space requirement at right angles to the key could be smaller because the diameter of the associated cylindrical tumbler pins is considerably smaller than the largest diameter of the conical countersunk hole measured on the key surface.
This largest bore diameter is in fact necessàry in order to form slides for the tumbler pins on the sides of the recess which extend in the longitudinal direction of the key up to the surface thereof and which are preferably inclined at an angle of 45 thereto. Thus, on removing the key, the pin tips thereof can perfectly ascend these side portions up to the surface of the key.
In connection with the space requirement in the area of the key surface, fundamentally the same applies for the oblong milled recesses as for the conical countersunk holes, but in this case the excessively large space requirement at right angles to the key is an even greater disadvantage and specifically when the flat key is used as a turning key with a double recess design.
In the case of flat keys, it is also known to permit the recesses drawn lengthwise for concealing the tumbler position and successively milled in a row in the longitudinal direction of the key to pass into one another~ whereby then the slides for the tumbler pins do not or do not all extend up to the key surface, but instead depending on 1051'~i4 the depth difference of successive step depthsJ differ in length.
However, here again at least in the case of the recesses with the greatest step depth of the 90 lateral permutation, the disadvantage of the excessively large space requirement at right angles to the key shank still exists (Swiss Patent No. 260, 517).
In addition, the excessively large three-dimensional space requirement particularly of milled oblong recesses of the 90 lateral permutation makes it impossible to use smaller key thicknesses with a reduced shank cross-section relative to the width and thickness such as would be desirable per se for lock cylinders with smaller diameters whilst retaining the number of permutations. In addition, due to the excessively large width of the recess at right angles to the key, the tumbler pins for an edge permutation to be provided on the narrow side of the key can only have a correspondingly reduced diameter or only a restricted insertion depth.
A further disadvantage of the hitherto known methods for manufacturing flat keys with longitudinally milled recesses is that they are either very complicated or in the case of profile milling machines with a plurality of juxtaposed control slide valves are too imprecise regarding the precision of the slides on the recesses for the desired clean ascent of the tumbler pins on removing the key.
BRIEF SUMMARY OF THE INVENTION
The problem of the invention is to obviate these disadvantages.
According to the invention, this problern is solved by a key of the type specified hereinbefore which is characterised in that at least one recess of the key has at least one planar side portion adjacent to the key surface which in the longitudinal direction of the key is parallel to the longitudinal median plane of the recess and to the axis of the associated tumbler pin, The invention also relates to a method for manufacturing the key which is characterised in that the recess is milled into the key with a milling cutter whose cylindrical portion radius corresponds to the distance of the planar side portion of the recess from its longitudinal median plane running in the longitudinal direc~ion of the key, whereby for producing rectilinear slides for the tumbler pins the milling cutter is displaced with a constant longitudinal feed speed and simultaneously with a constant speed for the depth feed motion and the subsequent depth retraction motion, whereby the feed and retraction commands for the cutter come from the same control source.
BRIEF DESCRIPTION OF THE DRAWINGS
Other and further objects of the present invention will be apparent from the following description and claims and are illustrated in the accompanying drawings which by way of illustration show preferred embodiments of the present invention and the principles thereof, and what are now considered to be the best modes contemplated for applying these principles. Other embodiments of the invention embodying the same or equivalent principles may be used, and structural changes may be made as desired by those skilled in the art w:ithout departing from the lOSi214 present invention and the scope of the appended claims. In the drawings show:
Fig. 1, a cut-away portior~ of a conventional flat key with a recess of the 90 lateral permutation in the form of a countersunk hole, in longitudinal section along the line I-I of fig. 2;
Fig, 2, the nat key of fig. 1 in a cross-section along the line II-II of fig. l;
Fig. 3, the milling cutter feed motion for making a longitudinally milled recess of the 90 lateral permutation of a conventional flat key, in a longitudinal section of the key.
Fig. 4, a cut-away portion of a flat key according to the invention with a longitudinally milled recess of maximum step depth of the 90 lateral permutation in a longitudinal section along the line IV-IV of fig. 5;
Fig, 5, the flat key of fig. 4 in a cross-section along the line V-V of fig. 4;
Fig. 6, the path of the milling cutter for making the longitudinally milled recess of the flat key according to figs. 4 and 5 in a longitudinal section of the key;
Fig. 7, the path of the milling cutter for making a nat key constructed according to the invention as a turning key with recesses of a 90 lateral permutation and a 45 additional permutation in plan view on a flat side of the key;
Fig. 8, a milling cutter arrangment for making the turning key .: .

105~1214 according to fig. 7 in a cross-section of the key and its fastening device along the line VIII-VIII of fig. ~i Fi g. 9, a recess of the 45 additional permutation of the turning key according to fig. 7 in plan view on a flat side of the key;
Fig. 10, the recess of maximum step depth of the 90 lateral permutation of the flat key according to figs 4 and 5 in a three-dimensional representation Fig, 11, a flat key with a row of recesses of the 90 lateral permutation extended on only one side in plan view on a narrow side of the key, partly in longitudinal section.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
.
Fig. 1 shows a cut-away portion of a conventional flat key lk with recesses for the tumbler pins of the 90 lateral permutation drilled out from its two flat sides as conical countersunk holes 2k, Fig. 1 shows one such recess 2k with an in the present case cylindrical tumbler pin 3 of diameter Dl, indicated with dotted lines, engaged therein, in a longitudinal section of the key lk. On the key surface 4 recess 2k has its largest diameter D2 whose size is dependent on the particular depth of bore t, i. e. in the case of a drill 5 with a conical bit of 90 it follows an equation D2 = 2t + B, whereby the quantity B corresponds to the diameter of a circular surface S5 of the base of the recess which results fro~n the conical bit of drill 5. If the same drill 5 is used for making all the recesses 2k of 90 lateral permutation with increasing bore 105121'~
or step depth t the largest diameter D2 of recess 2k measured on key surface 4 increases by double the amount of the particular depth increase.
Furthermore, for a recess 2k with the greatest occurring step depth t of the 90 lateral permutation, the maximum recess diameter D2 also follows the equation D3 = `~ D2, whereby D3 i9 the diameter of the cylindrical part of drill 5. This ensures that even with the greatest occurring step depth t two slides 6 for the tumbler pin 3 ars formed on the sides of the recess which extend from the base of the recess to the key surface 4, which are inclined by an angle of ~ = 45 relative to the latter and which are in the longitudinal direction of the key, so that on removing the flat key lk from the cylinder lock its conical tip cleanly ascends on this side portion 6 up to the key surface 4.
To ensure that when drilling the recesses 2k with the greatest step depth t the drill 5 does not undercut the key surface 4 with its cylindrical portion and therefore starting from the surface produces a cylindrical side portion on recess 2k which is perpendicular to the key surface 4 and impairs the clean ascent of tumbler pins 3. The drill diameter D3 is generally made somewhat larger than the largest diameter D2 of the deepest recess 2k as i9 shown in exaggerated manner in fig. 1.
Fig. 1 shows with dotted lines a recess 21k of the same depth t as recess 2k in fig. 1 in the form of a conical countersunk holeand extends in the longitudinal direction of the key on the same width either side, i. e. symmetrically from the position centre Z3 in order to conceal the actual position of the tumbler pin 3. This oblong recess 2'k is 10~1214 milled in the key shank with a milling cutter of the same outer contour and size as drill 5. Thus, as the recess 2'k is fundamentally only a lengthwise drawn conical countersunk hole Zk, in principle the same geometrical equations as in the case of recess 2k drilled in the key shank in the form of a conical countersunk hole apply in connection thereto for the greatest width measured on the key surface 4 at right angles to the key shank, i. e. its dependence on the step depth t on the one hand and the milling cutter diameter (corresponding to the drill diameter D3) on the other. Thus in the case of the oblong milled recess 21k, it is ensured that in the longitudinal direction of the key its sides form two slides 6 for the conical tips of the tumbler pin 3 extending up to the key surface 4 and inclined at an angle ~ of 45 relative thereto, which is indispensable for the clean ascent thereof onto and along the recess side during removal of the key.
Fig. 2 shows in cross-section the conventional flat key lk according to fig. 1 with the tumbler pin 3 engaged in the conical recess 2k.
Here the diameter ratio Dl/D2 of tumbler pin 3 and recess 2k clearly shows the excessively large space requirement of recess 2k at right angles to the key shank, whereby the space lost on either side of tumbler pin 3 measured on key surface 4 is in each case Vb. The reason is that the largest internal width of recess 2k on the key surface 4 is b = D2, although in actual fact only a width of Dl (plus the side tolerance) was necessary there.
In the case of milled recesses 2'k extended in the longitudinal _g _ 10512~4 direction of the key (cf. fig. 1), the excessive space requirements at right angles to key lk is even more pronounced because here the two loss quantities Vb are drawn out lengthwise in strip-like manner in the longitudinal direction of the key corresponding to the extension quantity of recess 2'k on key surface 4, which can in fact lead to considerable difficulties when making flat keys for use as turning keys with a double recess element, i. e. with two rows of recesses per flat side and intermediately recesses of a 45 additional permutation drilled out at an angle in two rows at 45 to the key surface 4, i. e. at least in each case narrows down the combination width of the total permutation or the maximum number of tumbler pins or recesses for a given key length.
The necessary side tolerance between the conical tip of the tuInbler pin 3 and the sides of the conical or oblong recess 2k or 2'k for the clean mounting of the tumbler pins 3 engaging in the particular recesses 2k or 21k on the base 18 of the recess and therefore for the completely satisfactory arrangement of the tumblers in the lock cylinder is designated by s in fig. 2. Conical or oblong recesses can be provided as edge steps for additional tumblers on the narrow side of the flat key designated by 7 in fig. 2.
Fig. 3 shows a hitherto conventional milling method for making conventional flat keys k with extended recesses 21k. During its total travel V~f for making a recess Zlk of the 90 lateral permutation, a milling cutter 5' firstly performs a feed motion perpendicular to the key lOSlZ~4 surface i and then a feed motion parallel thereto and finally a retraction motion perpendicular thereto. As a result of the movements of the milling cutter 5' perpendicular to the key surface 4, the two 45 slides 6 are produced along the key lk on the recess ends and in this connection there are considerable difficulties relative to the necessary mechanical control of the cutter movement.
Fig, 4 shows a cut-away portion of a flat key 1 according to the invention with an oblong recess 2 of the 90 lateral permutation of the greatest step depth Tl milled in the key shank on its flat side as well as a tumbler pin 3, which is here for example cylindrical engaged therein.
The trough-like recess Z extending in the longitudinal direction of key 1 has on the key surface 4 at right angles to the key a maximum width b2 which is the same as diameter Dl of the cylindrical tumbler pin 3, plus the side tolerance s thereof (cf. fig. 5). Furthermore, each of the longitudinal sides of the recess 2 has a planar lamellar side portion 8 adjacent to the key surface 4, said portion extending in the longitudinal direction of the key parallel to the axis of tumbler pin 3. Thus, the two planar side portions 8 also extend parallel to the longitudinal median plane of recess 2, i. e. to its main plane of symmetry running in the longitudinal direction of the key and perpendicular to the key surface 4 and also parallel to one another, whereby they are located in perpendicular manner on key surface 4. The height h of these two planar lamellar side portions 8 corresponds to the insertion depth of the cylindrical portion of the tumbler pin 3 engaged in the recess 2 designated by tz in fig. 4.

iO51214 The planar side portions 8 are interconnected pairwise at their ends by in each case a side portion 9 extending from the oblong base 18 of the recess to the key surface 4, whereby said portion ~ has the shape of a frustum surface sector and, corresponding to the 90 conical tip of the tumbler pin 3, is inclined at an angle of 45 to the key surface 4 or to the base 18 of the recess which is parallel thereto. Step-like lines 10 on the two ends of the oblong milled recess Z show in fig. 4 how the milling cutter, whose size and outer contour is now the same as that of the tumbler pin 3 used for making the same, is moved simultaneously, e4ually rapidly and therefore equally far in the horizontal and vertical direction x and z for producing a 45 slide 6 for the tumbler pin 3 extending from the base 18 of the recess up to the key surface 4, whereby on the right-hand side of fig. 4 it is shown that on further movement in the x direction it is retracted in the z direction.
Furthermore, the dotted lire s in fig. 4 show various momentary positions of the tumbler pin 3 assumed by the latter with reference to the oblong recess 2 which moves along beneath it on removing or inserting the flat key 1 from or into the key channel of the lock cylinder not shown for reasons of clarity in fig. 4. Furthermore, in fig. 4 the two dot-dash lines 11,12 show a recess of minimum length which corresponding to the flattened conical tip of tumbler pin 3 has a circular recess base and which is extended only relatively slightly in the longitudinal direction of the key on either side in the area of key surface 4 starting from the position centre Z3 of the engaged tumbler pin 3.

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.

lOS1214 Fig, 5 shows a cross-aection of the flat key 1 according to fig. 4 with the tumbler pin 3 engaged in the recess 2. This clearly shows that the space requirement for recess 2 at right anglss to the key is adapted to the diameter Dl of the cylindrical tumbler pin 3 due to the two planar lamellar side portions 8 located perpendicularly on key surface 4, and as a result considerable space-saving takes place on key surface 4 at right angles to the key shank. For comparison purposes, the dotted linesl3 in fig. 5 show the cross-sectional profile of a conventional recess milled in conventional manner (cf. 2~k in figs. 1 and 2), whereby the gain in space on either side of tumbler pin 3 measured at right angles to flat key 1 on key surface 4 is designated by the width Gb. Compared with the conventional reces s 2k or 2Ik according to fig. 2, the greatest recess width B2 is larger than the diameter Dl of tumbler pin 3 only by the side tolerance s despite the 45 slide 6 for the tumbler pin 3 once again provided at the recess ends (cf. fig. 4).
The saving of area Gb on the key surface 4 corresponds to a three-dimensional space saving which can be used for taking further tumbler pins and specifically for arranging additional recesses for the tumbler pins of a 45 additional permutation inclined to the key surface 4, as shown in fig. 5 by the tumbler pin 3z inclined by 45 to the key surface 4. Since, unlike in the conventional milling process (cf. figs. 1 to 3) it is now possible to select a maximum recess width B2 at right angles to the key for the milled recesses 2 which is independent of the production of the slides (6 in figs. 1, 3 and 4) necessary for the tu~nbler pin 3, iO51214 i. e. it now only corresponds to the constructional features of the cylinder lock and specifically the diameter Dl of tumbler pins 3, the width of the key shank can also now be made correspondingly smaller.
This is shown by the narrow side 7' of flat key 1 which is moved closer to the recess edge R2 at key surface 4 compared with the key narrow side 7 and this is also advantageous when manufacturing smaller diameter locking cylinders.
Fig, 6 schematically shows the milling method according to the invention for making the flat key 1 according to figs. 4 and 5. A milling cutter F3 whose size and outer contour corresponds to tumbler pin 3 in its travel Wf for producing the oblong recess 2 initially performs a linear feed movement inclined at an angle ti of 45 to the key surface 4 in accordance with fig. 4 resulting from the step-like lines 10 for the simultaneous and equally large feeds in the x and z direction (to the left in fig. 4). This is followed by a horizontal feed movement parallel to key surface 4 and finally by a linear retraction movement which is once again at an angle of 45 thereto and results from the step-like lines 10 (to the right in fig. 4). As a result of the two portions of the total milling travel Wf inclined by 45 to the key surface 4, the two 45 slides 6 for the tumbler pin 3 located in thebngitudinal direction of the key are produced at the two ends of the trough-like recess 2, whereas the horizontal cutter feed produces the two planar lamellar side portions 8 in the area of the central portion of the oblong recess 2 (cf. also fig. 4), whereby these two planar side portions 8 are located perpendicularly on :

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,: .
.

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10512i4 the key surface 4 and have a height h which corresponds to the insertion depth of the cylindrical portion of cutter F3. The height h of the two planar lamellar side portions 8 corresponds additionally to the insertion depth of the cylindrical portion of the tumbler pin 3 engaged in recess 2 designated by tz in fig. 4 because as stated the size and outer contour of cutter F3 corresponds to tumbler pin 3.
As for producing the 45 slides 6 in the x and z directions (cf. fig. 4), i. e. for the lengthwise and depth feed, the milling cutter F3 is moved simultaneously at the same speed and therefore equally far, the feed commands or pulses for these two feed movements can be taken from the same control source. For producing the oblong recesses 2 arranged successively in a row in the longitudinal direction of the key and which generally pass into one another, whilst having a differing step depth t in a single cutter pass, i. e. for so-called"continuous path milling "
a digitally controlled milling machine is used which is pre-programmed for the particular key permutation either by manual operation from a push-button console or by inserting punched tape. A so-called "computer-controlled" milling machine of this type is equipped with feed stepping motors for the longitudinal and depth feed of the cutter or cutters, said motors receiving their electrical pulses or feed commands simultaneously from the same control source, i. e. an oscillator serving as the pulse generator. The data for the particular key permutation given by the particular punched tape pattern or keyed on a push-button console in accordance with the permutation table are fed into a computer ~OS~Z14 ~vhich controls the different cutter feed processes according to the position, length, depth and speed. As the control source, the oscillator generates electronic pulses whose time-spacing can be varied and which serves to control the feed stepping motors with an accelerated, decelerated or constant speed. Thus the varyingly deep oblong recesses 2 of flat key l which are arranged successively and in series, as well as at the same time the additional recesses for the tumbler pins 3z of a 45 additional permutation inclined at an angle of 45 to the key surface 4 (cf. fig. 5) are milled into the key shank fully automatically in the continuous path milling process in a single cutter pass in the longitudinal direction of the key.
The milling cutter F3 for the oblong recesses 2 of the 90 lateral permutation corresponds to the tumbler pin not only as regards the shape and travel but also relative to the insertion depth in the key shank. This coincidence as regards shape and travel applies with reference to the flat key 1 passing beneath the tumbler pin 3 during the insertion or removal movement of the key. The reason is that in this case unlike the conventional milling process explained relative to figs. 1 to 3, the milling cutter F3 not only has the same diameter Dl and the same outer contour as the tumbler pin 3 (plus the side tolerance s according to fig. 5), but cutter F3 also completely simulates the movement sequence of tumbler pin 3 on key l, Fundamentally the same also applies for the additional recesses of the 45 additional permutation, . . .

105~14 Fig. 7 shows the cutter travel for m~king a flat key lw constructed as a turning key with a double recess design. On each of its two flat sides the finished key lw has two longitudinal rows of successive recesses not shown in fig. 7 (2 in figs. 4 to 6) for the preferably cylindrical tumbler pins 3 of the 90 lateral permutation (cf. figs. 4 and 5) as well as, between these two rows, two rows of additional recesses 2z for the tumbler pins 3z of a 45 additional permutation (cf. fig. 5) inclined at an angle of 45 to the key surface 4.
Milling first takes place in the milling direction 14 from the end portion 23 to the tip of the key 25 using the continuous path milling process to produce a row of oblong recesses 2 and subsequently, after transversely adjusting the cutter F3 (cf. fig. 6) relative to the key lw by the quantity q or inversely lw relative to F3, in the opposite milling direction 15 from the key tip 2S to the end portion 23, the other row of recesses 2 according to figs. 4 to 6 are produced in the key shank 16 of fig. 7.
The production of the additional recesses 2z of the 45 additional permutation which are inclined by 45 relative to the key surface 4 is explained relative to fig. 8.
Fig. 8 shows a group of three milling cutters Fz, F3, Fz juxtaposed at right angles to the key for producing the recesses 2 or 2z of the flat key lw constructed according to fig. 7 and a turning key in a cross-section through the key secured in a fastening device 17.
Milling cutter F3 (cf. also fig. 6) is used for making the two rows of recesses 2 of the ~0 lateral permutation (cf. figs. 4 to 6) whilst the 10512i4 tw~ nlillin~ cutters Fz are used to produce in each case one row of recesses 2z of the 45 additional permutation, ~hereby during its p~sses in the longitudinal direction of the key, cutter F3 alternately cooperates with one or other of the two cutters Fz. In fig. 8 cutter F3 cuts straight in the milling direction 14 according to fig. 7 from the end portion 23 towards the key tip 25 to form one of the two longitudinal rows of recesses Z of the 90 lateral permutation, i. e~ the upper row in fig, 7 and the left-hand row in fig. 8. However, during this pass of cutter F3, simultaneously the right-hand cutter Fz in fig. 8 is controlled in such a way that it mills the recesses 2z of the 45 additional permutation (cf. fig. 7) at pre-programme positions in the milling machine and which relative to the p~rticular side of the key channel in the cylinder rotor belong to this row of recesses 2 of the 90 lateral permutation, whereby said milling takes place in the same milling direction 14 in the key shank 16. Subsequently the fastening device 17 together with the flat key lw secured therein is transversely adjusted by the quantity q and then in the milling direction 15 from the key tip 25 to the end portion 23 (cf. fig. 7) the other longitudinal row of recesses 2 of the 90 lateral permutation is milled in the key shank 16, i. e. in fig. 7 the lower row and in fig. 8 following the transverse adjustment q of the fastening device 17 the right-hand row of recesses 2. Simultaneously, the other cutter Fz, on the left-hand side of fig. 8, mills the other recesses 2z of the 45 additional permutation ~cf. fig. 7) belonging to the said row of recesses Z of the 90 permutation in key shank 16 in the same milling 105~2~4 direction 15.
Ater the recesses 2 of the 90 lateral permutation and at the same time the recesses 2z of the 45 additional permutation have been milled in this way on one flat side of turning key lw, the key is removed from l:he device 17 and after turning by 180 is secured again so that now the other flat side of turning key lw can be provided in the same way as described hereinbefore relative to figs. 7 and 8 with the corresponding recesses 2 and 2z by means of the continuous path milling process. For producing the recess pattern of the flat side of a key, in this milling process either the fastening device 17, toget her with the key lw secured therein can be transversely adjusted by the quantity q relative to the fixed group of cutters Fz, F3, Fz, or conversely the set of cutters can be transversely adjusted by the same amount relative tc the fastening device 17 with the key lw secured therein (cf. figs. 7 and 8), whereby this merely constitutes a kinematic reversal of workpiece and tool movement.
Apart from the cutter F3 for the recesses 2 of the 90 lateral permutation, the digitally controlled milling machine is also pre-programmed for controlling the feed stepping motors of the two cutters Fz for the recesses 2z of the 45 additional permutation, whereby the recesses 2z (cf, fig. 7) produced by these cutters Fz are also milled into the key shank 16 by the continuous path milling process. Like cutter F3 the two cutters Fz completely simulate the movement sequence of tumbler pins 3~ of the 45 additional permutation (cf. fig. 5) as takes place on removin~ or inserting the flat key lw. In this connection, cutter Fz can be considered roughly as a tumbler pin 3z of the 45 additional permutation (cf. fig. 5) which seeks or takes the correct path inthe longitudinal direction of the key, Thus, for the tumbler pin 3z of the 45 additional permutation in place of a point support an areal support is now obtained in the area of the conical surface portion of recess 2z, together with a geometrically perfect recess configuration for optimum sliding and therefore clean ascent of the tumbler pin 3z on the recess side.
In fig, 9 which on an enlarged scale shows a cut-away portion from flat key lw according to fig. 7 in plan view on one of its flat sides is represented one of the recesses 2z of the 45 additional permutation milled in the milling direction 14. This recess 2z belongs to that row of additional recesses 2z milled by means of the right-hand cutter Fz in fig, 8 simultaneously with the pass of cutter F3 for the 90 lateral permutation in milling direction 14. These two rows of recesses 2 and 2z, in which the additional recesses 2z are inclined towards the main recess row 2 of the 90 lateral permutation and produced by cutters F3 and Fz in the same pass in the milling direction 14 belong together not only from the manufacturing standpoint, but also functionally in that the tumbler pins 3 or 3z engaging in these two rows of recesses are located on the same side in the locking cylinder rotor with reference to the key channel.
,2 In Fig. 9 relative to the recess 2z milled in the flat key lw at an angle of 45 to the key surface ~ in the milling direction 14, i. e. in the longitudinal direction of the key by means of the continuou-q path milling process shows the planar circular surface base 18 of the recess inclined by 45 to the key surface 4 resulting from the flat conical bit of cutter Fz (cf. fig. 8) as well as a conical surface recess wall portion 19 following the sal~e and corresponding to the conical tip of cutter Fz. It is also possible to see an approximately triangular flat recess wall portion 20 following on wall portion 19 and which results from the cylindrical part of cutter Fz and thersfore is perpendicular to the inclined base 18 or is at an angle of 45 to the key surface 4 but is directed oppositely to base 18. There are also two tran~itional wall portions 21 between the two wall portions 19 and 20 and which are produced by the cutter-axial depth feed or depth retraction of cutter Fz during its longitudinal feed in the milling direction 14. Finally it shows the two slides 6 extending up to the key surface 4 for the tumbler pins 3z (cf. fig. 5) of the associated 45 additional permutation row which are engaged or removed relative to recess 2z.
Fig.10 again shows the recess 2 of greater step depth of the 90 lateral permutation of flat key 1 according to figs. 4 and 5 for better comparison of its differentiating and coinciding features relative to recess 2z of the 45 additional permutation according to fig. 9, in this case in three-dimensional form. It is again possible to see the elongated flat base 18 of the recess parallel to the key surface, as well as the two parallel flat lamellar recess wall portions 8 (cf. also figs. 4 to lOSlZ14 6) resulting from the cylindrical part of milling cutter F3 inserted into the key material underneath key ~urface 4 (cf. fig. 6) and therefore perpendicular to the base 18 of the recess and to the key surface 4 and which, corresponding to the longitudinal displacement of cutter F3 (cf. fig. 6) extend in the longitudinal direction of the key. It is also possible to see the two conical surface wall portions 9 externally connected to the flat lamellar wall portions 8, resulting from the coIlical tip of cutter F3 and form the two 4S slides 6 for the tumbler pin 3 (cf. fig. 4), the two flat recess wall portions 22 diverging towards the key surface 4 and which also result from the conical tip of cutter F3 and extend in the longitudinal direction of the key are also shown.
Fig. 10 also shows that the elongated milled recess in key shank 16 only has a maximum width b2 at right angles to the key due to the flat side portions 8 perpendicular thereto, i. e. has a correspondingly reduced space requirement (cf. also fig. 5) so that compared with the conventionally milled recess 2k (cf. figs. 1 to 3) it can also be moved nearer to the narrow side 7 of flat key 1 (cf. also figs. 2 and 5).
Fig. 11 shows a longitudinal row of elongated recesses 2 of the 90 lateral permutation milled into key shank 16 by the continuous path Inilling process in direction 14 from end portion 23 to key tip 25 in a plan view on one of the two narrow sides 7 of a flat key la. Here again the recesses 2 which succeed one another in the longitudinal direction of the key and whose bases are again designated by the reference numeral 18 are extended on only one side in the direction of the end portion 23 or ~22-lOS~2i4 the '~ey stop face ~4 from ~l~e position centre Z3 of the again prefer.lbly cylindrical tumbler pin 3, wllereby the recess side 6 facing the key tip 25 and serving as 45 slides for tumbler pins

3 are at the same time su~porting slides for longitudinal pulling limitation of the inserted flat key la, which has already been turned somewhat from tile insertion or removal rotation position, as describedin Swiss Patent No. 591,001 issued June 15, 1977 to Bauer Kaba AG. As in figs. 4 and 10, recess 2 adjacent to the end portion 23 of the key has the greatest step depth Tl and therefore once again has two flat lamellar wall portions perpen-dicular to the key surface 4. In fig. 11 it is also indicated by means of dotted lines that the four recesses 2 which succeed one another in the longitudinal row and which have four different step depths Tl, T2, T3 and T4 can also be milled in key shank 16 so that they pass into one another, whereby in certain cases as in fig. 11 relative to the two recesses 2 with step depths T3 and T4 which pass into one another, the supporting side 6 which limits longitudinal pulling of the key can be o,mitted or its length can be reduced. Nevertheless, with reference to at least one~recess and preferably that with the greatest step depth Tl a supporting side 6 should always be provided in order to ensure longitudinal pulling limitation for the inserted flat key la which has already been turned somewhat from its insertion or removal rotation position, thereby effectively counteracting premature pulling on the key during its rotation, leading to so-called "hanging up" of tumbler pins of an additional permutation on "extraneous" stator bores and consequently the blocking of further rotation of rotor and key.
If the flat key la shown in fig. 11 with the recesses 2 of th'e 90 lateral permutation extended on only one side is constructed as a turning key with a double recess design, i.e.
being provided on each of its two flat sides with in each case ~051214 two lor~3itll~;nal rows Oe sllccessive recesses 2 of the 90 lateral permu~ation, as was e~plained relative to figs. 7 and 8, then only the recesses 2 of one row on each flat side of the key la is extended from its tumbler centre Z3 in the direction of end portion 23 (cf. fig. 11), so that only in this row of recesses are bearing sides for longitudinal pull limitation of the key la formed from the recess side 6 facing the key tip 25, whereas the recesses 2 of the other row are extended from their tumbler centre Z3 in the direction of key tip 25 and therefore in said .
other row of recesses no bearing sides for longitudinal pull limitation of the key are formed in the recess sides facing key tip 25 so that therefore the recesses 2 of this other row when assuming their function of identification between key and locking cylinder relative to the particular insertion position of the turning key la as so-called "active" recesses, they do not exercise a longitudinal pull limitation function for the inserted key. Therefore in the case of the flat key la constructed as a turning key according to fig. 11, the longitudinal pull limita-tion of the key in each of its two insertion positions only takes place on one of its two flat sides, which have identical recess designs and namely on that flat side on which the recesses 2 of the then "active" recess row 2 of the 90 lateral permutation is extended from tumbler centre Z3 in the direction of end portion 23 and consequently the longitudinal pull-limiting bearing sides 6 facing key tip 25 are formed (cf. fig. 11).
The opposing recess extensions in the two rows of recesses located on one flat side of a key and the equivalent arrangement of the recess extensions on the two flat sides of the flat key la constructed as a turning key according to fig. 11 can be explained relative to figs. 7 and 8 which also show a turning key lw in conjunction with fig. 11, the following system being used.

1(151214 .~s a~l-eacly c~plai~led relative to Figs. 7 and 8, milling cutter ~3(cf. fig. 8) on milling the two rows of recesses for the 90 lateral permutation in a first pass moves in the milling direction 14 from end portion 23 to key tip 25 and subsequently, after transverse adjustment Q of cutter F3 or fastening device 17, in the opposite milling direction 15 from key tip 25 to end portion 23. Then, following a 180 rotation in the fastening device 17 the keylw (cf. fig. 7) is re-secured and the same milling process with exactly the same cutter passes pre-programmed for both flat keys is now performed relative to the other key flat side in accordance with the arrowed line 14-Q-15 of fig. 7.
Thus, milling cutter F3 produces the same recess designs with an equivalent arrangement of the recesses for the 90 lateral permutation on the two flat sides of turning key lw.
When producing recesses 2 extended on only one side with longitudinal pull-limiting bearing sides 6 (cf. fig. 11), cutter F3 during the milling of such an elongated recess 2 should only leave behind it the recess extension extending from its tumbler centre Z3 in the direction of end portion 23 in order to ensure maximum manufacturing precision. The rèason is that the position and shape of the longitudinal pull-limiting bearing recess sides 6 are made more pre-cisely if produced from the solid key material on the return pass of the cutter, i.e. not when the cutter tip is first placed on the key surface 4 (cf. Figs. 7, 8 and 11) and its subsequent insertion into the material of key shank 16.

lOSlZi4 Tln~s, ~v]~cn pro(hlci1lg a tur~ g kcy with reccsscs 2 extcnded on only one side according to fig. 11 in its complete travel 14-Q-15 according to fig. 7, the cutter only produces the recess extensions extending fro~n the tu1nbler centre Z3 in the direction of end portion 23 and ~vhich are l~nown as "recess tails" only during the first longitudinal pass in the direction 1~ from end portion 23 to key tip 25, and therefore with the longitudinal pull limiting bearing recess sidcs 6 facing the key ~ip 25 as can be gathered ron~ fig. 11 in conjunction with fig. 7.
However, in the second cutter pass when milling the other longitudinal row oI recesses 2 on the same 1at side o the key but in the opposite milling direction 15 (cf. fig. 7), the recess extensions left behind the cutter as so-called "recess tails" extend from tumbler centre Z3 in the opposite direction to the key tip and therefore in the case of recesses 2 of this longitudinal row the recess sides facing key tip 25 do not orm bearing sides for the longitudinal pull limitation of the key. Thus, in the case of the flat key la constructed as a turning key with recesses of the 90 lateral permutation extended on one side, not only is the fact that the "rècess tails" in the two longitudinal rows of one flat side of key la point in opposite directions but alsQ the equivalent arrangement ~f t~o "recess tails" on its two flat sides is explained.
An important advantage of the key according to the invention or the method for making the same as explained relative to the previous embodiments is that the recesses with the greatest step depth of the 90 lateral permutation require much less space compared with the hitherto used recesses in the form of conical countersunk holes and particularly compared with the elongated recesses conventionally milled at right lOS~Z14 angles to the k~y duc to the ~lat lal-lellar recess wall portions perpendicular to the key surface, The space gained in this way on the kcy surface can be advantageously used for providing further tumbler pins, specifically a 45 lateral permutation which is particularly advantageous in the case of flat keys constructed as turning keys with a double recess design. Due to the reduced width of the deepest recesses o the 90 lateral permutation on the recess wall portion running in the lon~itudinal direction of the key and ormed on the key surface, the -~
narrow sides of the key can be moved closer together, i. e. the width of the key shank can be correspondingly reduced so that smaller diameter locking cylinders become possible. Furthermore, due to the avoidance of excessively large recess widths at right angles to the key, the possibility now exists in the case of the oblong recesses milled into the narrow side o the flat key as edge steps to increase the greatest step depth occurring with the edge permutation and therefore the step range wit~oUt thereby having to correspondingly increase the thickness of the key shanh and therefore the whole key. The reason is that the greatest recess width at right angles to the key both for the flat sides and the narrow sides of the key according to the invention is independent of the greatest step depth.
The continuous path milling process used for making the key in accordance with the present invention is characterised in connection with the large numbers involved in key manuacture by increased economy, particularly however by greater manufacturing precision whic~
is an important advantage when making flat keys in the form of turnin~
keys with a 45 additional permutation, i. e. when there is to be a relatively large number of recesses on the key surface. Despite the under-cutting of the key surface by the cylindrical cutter part the 105~i4 recesses with the g~e~test step dcpth o~ the 90 l~teral permutation or an, ed~e pcr~nutation still obtain geometrically absolutely perfect slides for the tumbler pins extending correctly up to the key surface and preferably incline~l by 45 relative thereto so that on rcmoving the key they cleanly ascend the recess side with their tip. The present continuous path milling process completely eliminates the hitherto encountered ilr~precisions of slides of key recesses which were unavoidable with conventional copy milling with juxtaposed control slide valves in the longitudinal direction of the key. In addition corrections of shape on the tumbler pin~ of the 45 additional permutation, such as the selection ~, of a somewhat reduced cone angle of e. g. 84 instead of 90 at the pin tip and the subsequent rounding at the transition from the co~ical tip to the cylindrical part of the tumbler pin at the expense of its guidance length in the rotor bore hitherto necessary due to this lack of precision of the slide are now eliminated. Furthermore, the continuous path milling process according to the invention also makes it possible in advantageous manner to make those keys In which the recesses of the 90 lateral permutation are drawn lengthwise to conceal the actùal position of the tumbler pins, but which according to Swiss Patent No. 591, 001 ~c~r .. . .
2~ : ~aint2ining a bearing side for longitudinal pull limitation of the inserted ~e~ which has, however, already been turned somewhat from its insertion or removal rotation position, are extended on one side only from the position centre in the : ~ direction of the end poxtion of the key, whereby here again the reduced recess width at right angles to the key like the geometrically perfect construction of the slides for the tumbler pins are advantageous.
The construc~ion of the key accordin~ to the invention and the inventive method for producing the same isin noway limited -28~

105~2~4 to flat keys and in fact it can be used for othe~ random key shank cross-sections, e.g. a cross-section with a radial arrange-ment of the tumbler planes. Instead of makin~ the tumbler pins which engage in the key recesses cylindrical, they can also be given non-circular cross-sections. Therefore, the invention is not limited to the embodiments described hereinbefore relative to the drawings, and numerous variants are possible thereto without passing beyond the scope of the invention.

.

Claims

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. A key for a cylinder lock with recesses for the tumbler pins, wherein at least one recess of the key has at least one planar side portion adjacent to the key surface which in the longitudinal direction of the key is parallel to the longitudinal median plane of the recess and to the axis of the associated tumbler pin.

2. In a key for a cylinder lock, the key being of the type having an elongated blade with means defining a plurality of recesses therein to receive tumbler pins of the lock, the improvement wherein the means defining at least one recess of they key includes first and second substantially parallel planar side wall portions adjacent to the key surface and extending in the longitudinal direction of the key blade, said wall portions being parallel to the longitudinal median plane of said recess and to the central axis of its associated tumbler pin; a sub-stantially planar base portion, said planar side wall portions being spaced from said base portion; third and fourth substan-tially planar wall portions extending between said base portion and said first and second wall portions, respectively; and sloping end wall portions defining rectilinear slide surfaces for cooperation with the associated tumbler pin, said slide sur-faces being aligned with the longitudinal dimension of the key blade and extending outwardly from said base portion.

3. A key for a cylinder lock, the key being of the type having an elongated blade with means defining recesses therein to receive tumbler pins for use with a lock having cylin-drical tumbler pins with frustoconical distal ends wherein at least one recess is one of a first plurality of recesses of a lateral permutation perpendicular to the key surface longitudi-nally arrayed along the key, said first recesses having a plurality of depths, said at least one recess having the great-est depth of said plurality of recesses and a maximum width sub-stantially equal to the diameter of its associated tumbler pin but slightly greater than said diameter to receive said pin close fitting, sliding relationship, the improvement wherein the means defining said at least one recess includes at least one planar side wall portion adjacent to the key surface and extend-ing in the longitudinal direction of the key blade, said wall portion being parallel to the longitudinal median plane of said recess and to the central axis of its associated tumbler pin, said planar side wall portion being one of two parallel side wall portions extending inwardly perpendicular to the key sur-face, said wall portions being spaced apart by a distance equal to said maximum width, the height of said wall portions in a direction perpendicular to the key surface being equal to the insertion depth of the cylindrical portion of its associated tumbler pin, and a substantially planar base portion, said planar side wall portion being spaced from said base portion; and sloping conical end wall surface portions defining rectilinear slide sur-faces for cooperation with the associated tumbler pin, said slide surfaces being aligned with the longitudinal dimension of the key blade and extending outwardly from said base portion.

4. A key according to claim 3 wherein at least one of the two slide surfaces extends up to the key surface.

5. A key according to claim 3 wherein said slide sur-faces are inclined by an angle of 45° to the key surface.

6. In a key for a cylinder lock, the key being of the type having an elongated blade with means defining a plurality of recesses therein to receive tumbler pins of the lock, the improvement wherein the means defining at least one recess of the key includes two planar side wall portions adjacent to the key surface and extending in the longitudinal direction of the key blade, said wall portions being parallel to the longitudinal median plane of said recess and to the central axis of its asso-ciated tumbler pin; a substantially planar base portion, said two planar side wall portions being spaced from said base portion;
and sloping end wall portions defining rectilinear slide surfaces for cooperation with the associated tumbler pin, said slide sur-faces being aligned with the longitudinal dimension of the key blade and extending outwardly from said base portion, said plur-ality of recesses including a second plurality of recesses for tumbler pins forming a permutation inclined relative to the key blade surface, at least one recess thereof having a base, a planar side wall portion adjacent to the key surface and inclined relative thereto in substantially the shape of an isosceles tri-angle, and a conical side wall surface portion between said base of the recess and said planar side wall portion.

7. A key according to claim 5 wherein said at least one recess of said second plurality of recesses forms a 45°
additional permutation, said planar side portion is inclined at an angle of 45° to the key surface, and wherein said conical side wall surface portion, and two transitional side wall por-tions and said planar side portion forms two slides for tumbler pins extending from the base of the recess up to the key blade surface and inclined by an angle of 45° relative to the latter said blade surface.

8. A key according to claim 2 wherein said at least one recess is extended in one longitudinal direction of the key from the center position of its associated tumbler pin in order to conceal the position of said tumbler pin and has an elongated recess base.

9. A key according to claim 8 wherein said recess is elongated in only one direction from the central position of its associated tumbler and the end wall portion of said at least one one recess facing away from the key tip is a conical surface forming a slide surface for its associated tumbler pin, said conical surface also limiting longitudinal motion of the in-serted key when said key has been turned from its insertion or removal position.

10. A key according to claim 2 wherein it is construc-ted as a turning key having recesses provided on both sides of the key blade.

11. In a key for a cylinder lock, the key of the type having an elongated blade with a plurality of recesses therein to receive tumbler pins of the lock, the lock having a plurality of tumbler pins forming a permutation inclined relative to the key blade surface, the improvement wherein at least one recess of said plurality of recesses includes a planar base portion spaced inwardly from the blade surface, a planar side wall por-tion spaced from said base portion and lying adjacent to the key blade surface and inclined relative thereto, said planar side wall portion having substantially the shape of an isosceles triangle and lying in a plane parallel to the longitudinal di-mension of the blade; and a conical side wall surface portion extending between said base portion and said planar side wall portion.

12. A method of manufacturing a key for a cylinder lock, the key being of the type having an elongated blade with a plurality of recesses therein to receive tumbler pins of the lock, wherein at least one recess of the key includes at least one planar side wall portion adjacent to the key surface, said wall portion being parallel to the longitudinal median plane of said recess and to the central axis of its associated tumbler pin, comprising the steps of milling the recess with a milling cutter having a cylindrical portion with a radius corresponding to the distance between said planar side wall and the median plane of the recess parallel to the longitudinal axis of the key, simultaneously feeding the cutter perpendicularly into the key material and longitudinally along the key at equal speeds to form one end portion of the recess, and simultaneously re-tracting the cutter perpendicularly from the key and moving the cutter longitudinally along the key to form the other end por-tion of the recess, the feed, moving and retraction commands for the cutter coming from the same source.

13. A method according to claim 12 wherein the recess-es of the 90° lateral permutation which succeed one another in a longitudinal row are successively milled in a single milling pro-cess which takes place in the longitudinal direction of the key into the key shank by means of a milling cutter, the diameter of the cylindrical part of the cutter corresponding to the greatest width of the deepest recess at right angles to the key, and wherein for each recess for producing slides for the tumbler pins inclined at an angle of 45° relative to the key surface, the milling cutter is guided by a continuous path control system with identical length and depth feeds or depth retraction.

14. A method according to claim 12 wherein the recess-es of an additional permutation inclined relative to the key surface and arranged successively in a longitudinal row are successively milled in the key shank in a single cutter pass in the longitudinal direction of the key and wherein, for each re-cess for producing slides for the tumbler pins inclined at an angle of 45° relative to the key surface, the milling cutter is guided by a continuous path control system with identical length and depth feeds or depth retraction.

15. A method according to claim 14 wherein the recess-es of the longitudinal row belong to an additional permutation inclined at an angle of 45° relative to the key surface.

16. A method according to claim 12 wherein the two rows of recesses of the 90° lateral permutation and the addition-al permutation are simultaneously milled in the key shank in the same milling direction with two continuous path controlled milling cutters.