US2812816A

US2812816A - Key cutting apparatus

Info

Publication number: US2812816A
Application number: US343582A
Authority: US
Inventors: Hoffman Harold
Original assignee: Individual
Current assignee: Individual
Priority date: 1953-03-20
Filing date: 1953-03-20
Publication date: 1957-11-12
Anticipated expiration: 1974-11-12

Description

HOFFMAN KEY CUTTINGAPPARATUS M, s m.\.

i U a Nov. 12, 1957 H. HOFFMAN KEY CUTTING APPARATUS 3 Sheets- Sheep 2 Filed March 20, 1953 Nov. 12, 1957 H. HOFFMAN KEY CUTTING APPARATUS 5 Sheets-Sheet 3 Y Filed March 20 1953 5 4 am 4 w L/w 4 J I 8 i I 2 W 5 f 4 -0 19/ W M a United States Patent KEY CUTTING APPARATUS Harold Hoffman, Chicago, Ill. Application March 20, 1953, Serial No. 343,582 Claims. (Cl. 164-50) This invention relates to key cutting apparatus and has more particular reference to key cutting apparatus of the type used by locksmiths for the notching of replacement keys for all automotive locks.

In general it is the purpose of this invention to provide improved key notching apparatus of the character described which features exceptionally simple means for presenting a key blank to notching means operating in a fixed cutting zone, to assure accurate spacing and depth of the notches to be cut.

More specifically it is the purpose of this invention to provide a key notching appaartus of the character described wherein the means for presenting the key blank to the cutting zone comprises a carriage mounted for swinging motion to and from an operative position about an axis spaced from the cutting zone and adjustable along a path parallel to said axis, and a clamp structure for the key blankmounted on the carriage for bodily motion therewith and for motion relative thereto toward and from the cutting zone along a path substantially normal to the axis about which the carriage may swing. This enables the clamp structure to be swung with the carriage to a position spaced from the cutting zone to facilitate securement of a key blank in the clamp structure, and inspection of a partially notched blank or removal of a completely notched key from the clamp structure.

In this connection it is another object of this invention to so mount the carriage that it may be swung out of its operative position to enable inspection of apartly notched blank without disturbing the notch space adjustment of the carriage.

It is a further object of this invention to provide a key notching apparatus of the character described wherein the initial propulsion of the clamp structure toward the cutting zone to bring a key blank in the clamp structure into notching position effects locking of the carriage against swinging motion out of its operative position.

Still another object of this invention resides in the provision of a key notching device of the character described wherein both the carriage and the clamp structure are propelled back and forth along their respective paths at right angles to one another by screws having detachable manual control knobs thereon bearing a plurality of matched sets of indicia, each knob being cooperable with a reference point to indicate the degree of rotation of the knob and its screw necessary to set the carriage and clamp structure at the proper locations necessary to achieve accurate spacing and depth of the notches for any of a plurality of different types of automotive keys. In this connection it is another object of this invention to provide a novel rotation transmitting connection between each of the control knobs and its screw by which the control knobs are readily interchangeable with others having different matched sets of indicia thereon without danger of applying the control-knobs to their screws in positions angularly misaligned with respect to the indicia thereon.

Still another object of this invention resides in the pro vision of a novel punch and die construction for key notching apparatus of the character described, along with an improved method of making the punch and die.

With the above and other objects in view, which will appear as the description proceeds, this invention resides in the novel construction, combination and arrangement of parts substantially as hereinafter described and more particularly defined by the appended claims, it being understood that such changes in the precise embodiment of the hereinafter disclosed invention may be made as come within the scope of the claims.

The accompanying drawings illustrate one complete example of the physical embodiment of the invention constructed acconding to the best mode so far devised for the practical application of the principles thereof, and in which:

Figure 1 is a perspective view of the key cutting apparatus of this invention.

Figure 2 is a side elevational view of the apparatus shown in Figure 1, with portions thereof broken away and shown in section;

Figure 3 is a sectional view taken through Figure 2 along the plane of the line 3-3;

Figure 4 is an enlarged fragmentary sectional view taken through Figure 3 along the plane of the line 4-4;

Figure 5 is a group perspective view illustrating the manner in which the control knobs are connected with their screws to impart rotation thereto;

Figure 6 is an enlarged fragmentary cross sectional glow taken through Figure 2 along the plane of the line 6; and

Figure 7 is an enlarged fragmentary cross sectional yiew taken through Figure 2 along the plane of the line Referring now more particularly to the accompanying drawings in which like reference characters designate like parts throughout the several views, the numeral 5 generally designates the frame of the key cutting apparatus of this invention. The frame comprises a substantially U-shaped base providing spaced supporting legs 6, and a post 7 extending upwandly from the rear or bight end of the U-shaped base. At the front thereof immediately above the base the post is recessed as at 8 to provide space for a die block 9. The die block seats upon a platform 10 extending forwardly from the bight end of the base flush with the upper edges of the legs 6 of the base. The die block is secured to the platform on the base as by screws 12 threaded upwardly into the die block from beneath the platform.

The portion of the post which overlies the die block is provided with a vertical bore 14 communicating with a vertical slot 15 in the upper end of the post. This bore accommodates a key notching punch 17, and the slot 15 in the upper end of the post receives one end of a lever 18 pivotally mounted on a pin 19 anchored in the upper end of the post and extending across the slot 15 to constrain the lever to pivotal motion about a horizontal axis substantially directly over the bore 14.

The upper end of the punch is provided with a cylindrical cam follower 20 loosely slidably and rotan'ly fitting the bore 14 and extending into the slot 15 for cooperation with a cam surface 21 on the pivoted end of the lever 18. A leaf spring 22 carried by the upper end of the post is preferably interposed between the upper end of the punch and the cam surface 21 to provide a good wearing surface along which the cam slides during downward and forward pivotal motion of the lever to cam the punch downwardly in its cutting stroke into a hole 24 in the die block. A compression spring 25 encircling the punch and confined between its cylindrical upper end portion 20 and the top of the die block yieldingly resists dowm ward camming of the punch and at all times maintains the upper end of the punch in engagement with the cam surface 21 on the operating lever 13.

The punch is provided with fiat forwardly converging sides 27 which define a blunt edged nose 28 on the front portion of the punch by which substantially flat bottomed V-shaped notches may be cut in one edge of a key blankbrought under the punch and partly over the hole 24 in the die block. During the notching operation, the edge of the blank to be notched is rested upon a supporting surface 29 on the die block defined by a cutout 30 therein opening to the front of the block. The hole 24 in the die block, of course, has a shape corresponding to the cross section of the punch and when the latter is driven downwardly thereinto by the operating lever 18, an exceptionally accurate cut or notch will be made in the edge of a key blank lying on the suporting surface 29 by reason of the fact that the punch has an extremely close fit in the cavity, as will be brought out later.

The two legs 6 of the base extend forwardly in spaced apart parallel relationship and conjointly support a notch indexing shaft 32 at their outer ends. The opposite ends of the shaft are reduced in diameter and are received in bushings 34 pressed into the legs to support the shaft for rotation about a horizontal axis normal to the legs 6. The larger diameter portion of the shaft lying between the legs is screw threaded and shoulders 35 at the opposite ends thereof bear against the adjacent ends of the bushings 34 to preclude axial motion of the screw shaft 32 relative to the base. One reduced end 36 of the shaft projects a distance beyond the outer side of its leg 6 to receive a manual control knob 37 thereon by which an operator of the apparatus may impart back and forth rotation to the shaft.

Mounted on the notch indexing shaft 32 is a carriage 39 having a threaded aperture in its front portion in which the screw threaded intermediate portion of the shaft is received so that rotation of the shaft in opposite directions propels the carriage bodily lengthwise of the shaft back and forth between the two legs 6 of the base. The screw threaded connection between the carriage and the shaft also provides for tilting motion of the carriage about the shaft axis between a substantially horizontal operative position and an inoperative position seen in construction lines in Figure 2. The horizontal, or operative position of the carriage is defined by the engagement of its rearwardly extending, end portion 40 upon a ledge 41 on the base projecting forwardly from the platform thereon; and the weight of the rear portion 40 of the carriage normally maintains the carriage in its horizontal position regardless of the direction of rotation of the screw shaft 32 to propel the carriage in one direction or the other.

A clamp structure, indicated generally by the numeral 42, is provided to hold a key blank in position to have notches cut in one edge thereof. This clamp structure is mounted upon the rear portion 46) of the carriage for bodily motion therewith and for back and forth horizontal motion relative to the carriage in a direction normal to the axis of the screw shaft 32. For this purpose the rearwardly extending portion of the carriage has a substantially flat top surface, upon which the body 43 of the clamp structure seats, and has a slot 44 therein opening to its rear extremity to slidably receive the upright stem 45 of a slide block 46 of inverted T-shaped cross section. The slide block is secured to the underside of the body 43 by a single screw 46' with the end of its stem received in a shallow slot 44' in the underside of the body to preclude swivelling of the slide block about the axis of the screw 46'. The head 45 of the inverted T-shaped slide block engages under the rear portion 49 of the carriage to hold the clamp structure from lifting off of the carriage.

Accordingly, the clamp structure is constrained to reciprocatory motion relative to the carriage toward and from the fixed cutting zone defined by the key notching means on the base, along a path normal to the axis of the screw shaft 32. Such back and forth motion of the clamp structure relative to the carriage is essential not only to enable a key blank secured in the clamp structure to be advanced rearwardly into the cutting zone, but to also enable the adjustment of the depth of the notches to be cut in the edge of the key blank presented to the key notching means.

The clamp structure is provided with'cooperating stationary and movable jaws 47 and 48, respectively, at its rear portion facing the die block. The stationary jaw 47 is on the body 43 of the clamp structure and is provided by a substantially horizontal ridge on the rear of the body having its top surface lying in the plane of the supporting surface 29 on the die block and parallel to the fiat supporting surface on the carriage upon which the clamp structure slides.

The movable jaw 48 overlies the stationary jaw and is provided by a downwardly directed flange along the rear of a substantially channel-shaped clamp 49. A downwardly extending flange 50 at the front of the clamp received in a shallow cross slot 51 in the body 43 provides a fulcrum about which the movable clamp is supported for limited pivotal motion about an axis parallel to the axis of the screw shaft 32. Hence, the jaws 47 and 48 cooperate with one another to receive one edge of a key blank B to be notched, and the movable jaw is forced downwardly into clamping relationship with an edge of the key blank between the jaws by means of a screw 53 passing loosely through the body of the clamp and threading into a hole in the body 43 of the clamp structure. The screw 53, of course, has a flange 54 which bears against the top of the clamp to press the same downwardly as the screw is turned into its hole in the body of the clamp structure. A compression spring 55 reacting between the underside of the clamp and the body of the clamp structure yielding'ly urges the clamp upwardly to release a key blank from the jaws when the clamp screwis backed outwardly of its threaded hole.

The clamp structure has a screw threaded connection with the carriage by which it may be propelled back and forth relative tothe carriage toward and from the cutting zone to provide for adjustment of the depth of the notches to be'cutin a key blank carried by the clamp structure. This screw threaded connection comprises a bushing 57 fixed in the body 43 and having a threaded hole normal to the axis of the screw shaft 32 and opening to the front of the body of the clamp structure. A second screw shaft 58 supported by the carriage but restrained against axial motion relative thereto has its rear end portion threaded into the bushing 57. The screw shaft 58 has a reduced front end 59 freely rotatably journalled in;a hole in an upstanding portion 60 on the carriage, and it projects forwardly through the portion 60 to receive a manual control knob 61 on its front extremity.

The junction of the threaded portion of the screw shaft 58 with its reduced front end portion 59 defines a shoulder 62 which engages the rear of the upstanding portion 60 on the carriage to preclude forward axial motion of the shaft relative to the carriage; while a collar 67 inside the inner end of the control knob 61 is secured to the forwardly projecting end of the shaft 58 and engages the front of theupstanding portion 60 to preclude rearward axial motion of the shaft with respect to the carriage. It will be apparent, therefore, that rotation of the screw shaft 58 by its knob 61 will impart either forward or rearward sliding motion to the clamp structure depending upon the direction in which the knob is rotated; 1

The upstanding portion 60 of the carriage also provides an abutment whichis engaged by the clamp structure to define the inoperative position thereof retracted from the cutting zone, and at which a key blank held by the jaws 47 and 48 lies outside the cutting zone. In this retracted position of the clamp structure the rear free edge of the key blank B, in which notches are to be cut, may still rest on the extreme forward edge portion of the supporting surface 29, a slight distance forwardly of the hole 24 therein. Consequently, rotation of the control knob 61 in a counterclockwise direction as viewed in Figure 1 effects rearward propulsion of the clamp structure, to the left as seen in Figure 4, to advance the key blank held in its jaws into the cutting zone, or more particularly, bring its exposed rear edge over the hole 24 so that a V-shaped notch can be cut in its rear edge at a location along the length of the blank determined by the notch indexing adjustment of the carriage under the control of the knob 37.

It is to be understood that the notches are cut in the rear edge of the key blank successively starting from the extreme end of the blade as indicated in Figure 3, each time indexing the blank longitudinally by rotating the control knob 37 a predetermined angular distance in the same direction, and each time adjusting for the desired notch depth by rotation of the control knob 61 predetermined angular distances in the proper direction.

As brought out hereinbefore, the carriage may be tilted out of its operative horizontal position shown in solid lines in Figure 2 to carry the clamp structure upwardly and forwardly away from the cutting zone. In the tilted position seen in construction lines in Figure 2, a key blank may be readily inserted into or removed from the jaws of the clamp structure, or a notch cut in the blank may be inspected without disturbing the notch indexing adjustment of the carriage. This last feature results from the fact that there will always be sufiicient friction in the screw threaded connection between the carriage and the shaft 32 that the latter will rotate with the carriage during tilting thereof to and from its operative position.

Such tilting motion of the carriage is possible, however, only in the retracted or inoperative position of the clamp structure at which a tongue 64 projecting rearwardly from the underside of the slide block 45 clears the underside of the ledge 41 on the platform of the base.

As shown in Figure 4, the tongue 64 just clears the ledge 41 when the clamp structure is fully retracted, so that initial rearward propulsion of the clamp structure along the carriage to bring a key blank into cutting position effects engagement of the tongue under the ledge 41, as shown in construction lines, to preclude tilting motion of the carriage and the clamp structure thereon out of operative positions. In other words, tilting of the carriage is impossible whenever the clamp structure is in an operative position presenting a key blank to the notching means, and the clamp structure must be retractedby its control'knob 61 if for any reason it is desired to swing the carriage out of its horizontal position either for inspection of a notch cut in the key blank or for removal of a completely notched blank from the jaws of the clamp structure.

Attention is directed to the fact that each of the control knobs 37 and 61 has a novel detachable driving connection with its shaft fora purpose now to be described. Since these connections are identical, a description of one will sutfice for both. Referring to Figure which illustrates the knob 37 and the reduced end portion 36 of the screw 32, the inner end of the knob is provided with a counterbore 66 of a diameter and depth to receive a collar 67 fixed on the end portion 36 of the screw shaft and lying directly against the outer side of the adjacent leg 6 of the base. One or more set screws 68 threading radially into the collar are provided to permanently secure the collar to the shaft.

The knob 37 is drivingly connected with the screw shaft 32 through the collar 67 and for this purpose the collar and the knob are provided with male and female driving elements which interengage with one another when the knob is properly angularly disposed on the reduced end portion of the shaft to provide a rotation transmitting connection between the knob and the shaft. The driving elements, in the present case, comprise an eccentric pin 69 on the collar projecting forwardly from the outer face thereof parallel to the axis of the screw shaft and slidingly but snugly received in a hole 70 in the knob opening to the bottom of its counterbore 66.

One or more set screws 71 may be provided to detachably hold the knob on the reduced extremity of the shaft but it should be understood that these set screws have no other function, the knob being located angularly on the shaft solely by the cooperating male: and

female driving elements

69 and 70.

As indicated in Figuresl and 5, a plurality of

circumferential bands

72, 73 and 74 are delineated on each of the knobs, one band for each of three different types of automotive keys which may be notched by the apparatus of this invention. Each band, of course, is marked with the name of the particular type of lock or automobile upon which the lock is used. For example, the circumferential bands 72 at the inner ends of both knobs may be calibrated for the keys of all General Motors automobiles; the bands 73 calibrated for the keys of all Chrysler automobiles; and the bands 74 calibrated for the automotive keys marked Briggs and Stratton.

Suitable indicia, such as the lines and numerals indicated, are delineated on the sets of bands on the two knobs to facilitate the adjustment of the carriage and the clamp structure. Thus, the indicia on any one band on the knob 37, when aligned with a fixed reference point 76 on the base will readily enable an operator of the apparatus to index the carriage to the proper position along the screw shaft 32 for the cutting of any one of the notches in a key blank secured in the clamp structure; while the indicia on the corresponding or matching band on the knob 61, when aligned with a fixed reference point 77 on the cairiage enables the clamp structure to be adjusted towardand from the key notching means to secure the desired depth for the notch to be cut.

The fixed reference point 76 on the base may be a line delineated upon a plate of clear plastic 78 secured to the upper edge of the leg 6 to overlie the knob 37, the line lying in a vertical plane containing the axis of the screw shaft 32. Preferably the plastic plate is disposed as close as possible to the periphery of the knob 37 so as to minimize the possibility of errors in the alignment of any of the indicia on the various bands thereof with the reference line 76.

The fixed point 77 is also preferably a line delineated on a clear plastic plate 79 secured to the top of the upstanding portion 60 of the carriage, and this line also lies in a vertical plane containing the axis of the screw shaft 58 and closely overlies the periphery of the knob 61.

When notching a General Motors key for instance, the indicia on both bands 72 of the two knobs are employed throughout the entire notching operation, the indicia on the knob 37 corresponding to positions of the notches lengthwise of the key blank and the indicia on the knob 61 corresponding to the various depths of the notches to be cut. It is understood, of course, that locksmiths employing the key notching apparatus of this invention will ordinarily be provided with codes or decoding apparatus to enable any particular key of the different types mentioned to be notched on the apparatus.

Since there are several more types of keys for automotive locks than the three types mentioned, this invention makes it possible to readily convert the apparatus for the notching of such different types of keys merely by the substitution of a different set of matched control knobs for the

knobs

37 and 61 described. Any number. of such matched sets of knobs can be provided to take care of future needs as new types of automotive locks are put on the market.

When changing knobs, it will be understood that the inter-engagement of the male and female driving ele-.

ments

69 and 70 automatically locates the knobs angularly on their respective shafts. Consequently, since the holes 70 in the bottoms of the knob counterbores can be accurately located angularly with respect to the indicia thereon by the manufacturer of the apparatus, the locksmiths in changing from one set of matched knobs to another cannot fail to secure the knobs on their shafts in the proper angular position thereon.

All notch spacing and depth adjustments afforded by the matched sets of control knobs, of course, are predicated upon accurate location of the blanks to be notched in the jaws of the clamp structure. For this purpose the side of the body 43 adjacent to the knob 37 may itself provide a stop engageable by an abutment on certain types of key blanks to locate those blanks lengthwise of the jaws.

Other gage means must be provided for the other types of keys having a locating abutment on the opposite edge of the key blank which is presented to the notching means. In the present case this gage means comprises a lever 81 normally received in a slot 82 in the body 43 of the clamp structure opening to the top thereof near its side adjacent to the control knob 37. The rear of the lever is pivoted on a pin 83 carried by the body 43 so that its front end may be swung rearwardly, about a horizontal axis parallel to the axis of the screw shaft 32 over the blade of a key blank in the jaws. A locating finger 84 on the free end of the lever is adapted to extend over the exposed edge of the key blank in the jaws for engagement with the stop abutment on the blank to enable the same to be properly located lengthwise of the jaws.

The lever 81 is yieldingly biased to a retracted position received in the slot 82 by means of a torsion spring 85 having one end fixed to a screw 86 in the body and its other end fixed to the pin 83 upon which the gage lever is mounted, it being understood that the lever is fixed to the pin in any suitable manner.

In all cases, the key blank is secured in the jaws with the forwardly facing edge of the blank against the rear face of the body 43 to assure that the blank will be parallel to the carriage screw 32.

Referring again to the punch and die, it is important to note that these elements of the key notching apparatus of this invention are not only novel in construction but that they are made by a new and novel method which assures the utmost accuracy in notching key blanks, substantially without producing burrs as the result of the notching operation.

As stated previously, the die block has a notch 01 slot 30 opening to its front which has the effect of dividing the block into an upper punch guiding portion 88 and a lower notching portion 89 containing the hole 24. The hole in the guide portion 88 of the die block, of course, is made to very accurately fit the shank of the punch so that the punch is guided for vertical motion primarily by its sliding fit therein, rather than in the bore of the post above the die block as was the practice heretofore. Also due to the non-circular cross sectional shape of the punch and the hole in the guide portion of the block, the punch is held against rotational movements thereby eliminating the troublesome and costly practice heretofore resorted to in accurately keying the punch in the bore of the post and locating the die block with respect to the bore in the post.

According to the present invention, the punch is merely loosely guided in the bore 14 of the upright post of the apparatus, and is not in anywise restrained against rotation thereby. Additional guidance as well as rigidity is afforded the punch by reason of the fact that it has a tail portion 91 at its rear projecting downwardly from its cutting face 92 and at all times engaging in the hole 24 to bear against the rear edge thereof. Thus, during the downward cutting stroke of the punch any tendency for the punch to be cammed rearwardly, due' to the slant of its cutting face, is precluded by the tail piece 91.

The punch and die are also made by a unique method which involves first shaping and grinding of the punch to the desired configuration shown, after which the punch is hardened. The die block before hardening thereof, is notched at one side thereof to define the spaced upper and lower flanges on the block. Thereafter the flanges are broached to provide aligning punch receiving holes therein which substantially correspond to the crosssectional shape of the punch. The holes are accurately machined along their cylindrical rear portions to fit the cylindrical rear portion of the punch, but at their front edge portions, the holes are made slightly undersize, about .030".

After the holes have been made in the manner described, the finished and hardened punch is driven downwardly through both holes in the die block to actually shear away the softer metal of the block along the converging front edges of the holes, to thus assure that the hole in the upper guide flange of the block and the lower hole 24 will very accurately fit the punch. This assures against the possibility of lateral or rotational movements of 'the punch in the die, and practically eliminates the formation of burrs on the key blanks notched thereby.

During the shearing operation described, of course, the downwardly extending tail along the rear of the punch enters both holes in the die block in advance of the cutting face of the punch, with the result that the punch cannot cam itself rearwardly away from the sloping front edges of the holes as it cuts through the die block. After the die block has been punched out in the manner described and hardened, it is secured to the platform on the base while the punch is in position within the bore 14 and with its lower end received in both holes of the die block. This materially simplifies proper location of the die block on the base; and it will be seen that the punch and the die cooperate to provide a unit which is more or less independent positionally of the punch actuating means on the base.

From the foregoing description taken together with the accompanying drawings it will be readily apparent to those skilled in the art that this invention provides an improved key notching apparatus featuring a pivotally mounted carriage which is automatically locked against swinging motion in consequence of initial propulsion of the clamp structure rearwardly toward the notching means; that it features a simple but unique manner of providing for proper indexing and notch depth adjustment through the provision of interchangeable matched control knobs for the screw shafts by which such adjustments are effected; and provides a punch and die of improved construction wherein the punch is guided solely by the die block and the punch and die are made by a new and improved method which assures greatest accuracy of the notching operations substantially without burr.

What I claim as my invention is:

1. In a key notching device: an elongated base; means near the rear end of the base defining a cutting zone fixed with respect to the base; a carriage extending horizontally rearwardly along the base toward said cutting zone; a horizontal screw threaded connection between the front portions of the carriage and the base providing for swinging of the rear portion of the carriage upwardly and forwardly away from the cutting zone about the axis of said screw threaded connection, said screw threaded connection providing for propulsion of the carriage in opposite directions along a path parallel to said axis; means on the base engageable by the carriage to define said horizontal position thereof; a clamp mounted on the rear portion of the carriage for bodily motion therewith and for back and forth motion relative thereto lengthwise of the base, toward and from the cutting zone; a screw threaded connection between the carriage and the clamp providing for propulsion of the clamp toward and from the cutting zone; and cooperating means on the carriage and the base brought into interengaging relationship in consequence of propulsion of the clamp to a position adjacent to the cutting zone to preclude swingin'g motion of the carriage out of its horizontal position.

2. In a key notching device; a base having means thereon defining a cutting zone fixed with respect to the base; a carriage supported on the base in a substantially horizontal position and having front and rear portions, the rear portion of the carriage being disposed adjacent to the cutting zone; a clampmounted on the rear portion of the carriage for recip'rocatory motion relative to the carriage toward and from the cutting zone; cooperating stops on the clamp and the carriage for limiting motion of the clamp away from the cutting zone to define the retracted position of the clamp '21 which a key blank held hereby is spaced from the cutting zone; a screw threaded connection between the front portion of the carriage and the base by which the carriage may be propelled in opposite directions along a path normal to the path of reciprocatory movement of the clamp to impart notch indexing motion to the clam said connection providing for swinging of the rear portion of the carriage and the clamp thereon upwardly and forwardly away from the cutting zone to a position facilitating insertion of a key blank into the clamp; and cooperating means on the carriage and the base interengageable with one another in the horizontal position of the carriage whenever the clamp is moved from its retracted position to a position adjacent to the cutting zone, for holding the carriage against swinging motion out of its horizontal position.

3. In a key notching device having a base and key notching means on the base defining a cutting zone fixed with respect to the base, the improvement thereof which comprises: a carriage supported on the base for tilting motion toward and from a substantially horiozntal operative position about an axis spaced from said cutting zone, and for back and forth motion along a path parallel to said axis, said carriage having a portion extending from its axis toward the cutting zone; a clamp engageable with one edge of a key blank for presenting the opposite edge of the blank to said notching means; means mounting the clamp on said portion of the carriage for bodily motion relative thereto along a path normal to the pivot axis of the carriage so that the clamp may be moved toward and from the cutting zone in the horizontal position of the carriage to provide for adjustment of the depth of notches to be cut in a key blank in the clamp; manually operable means on the base connected with the carriage for driving the same back and forth along said path parallel to its pivot axis to thereby impart notch indexing motion to the clamp; manually operable means on the carriage connected with the clamp for driving the clamp toward and from the cutting zone; and cooperating means on the clamp and the base interengageable with one another in the horizontal position of the carriage as a consequence of movement of the clamp toward the cutting zone a distance to bring a key blank in the clamp into cutting position, for precluding tilting of the carriage out of its horizontal position.

4. In a key notching device of the type having a base, a clamp movable along a defined path toward and from a fixed cutting zone on the base to provide for adjustment of the depth of notches to be cut in a key blank secured in the clamp, and a carriage for carrying the clamp back and forth along another defined path normal to said first designated path to impart notch indexing motion to the clamp: manually controlled means on the base connected with the carriage for driving the same and the clamp thereon back and forth along said other path; manually controlled means on the carriage connected with said clamp for propelling the same back and forth relative to the carriage along said first designated path; means esteem i l0 mounting the carria e on the base for tilting motion out of an operative position about an axis spaced from the cutting zone and parallel to said other path to enable the clamp to be swung with the carriage to a position a distance away from the cutting zone and at which a key blank may be readily secured in or removed from the clamp; and cooperating means on the clamp and the base interengageable with one another upon movement of the clamp along said first designated path to a position adjacent said cutting zone to preclude such tilting motion of the carriage whenever the clamp is in an operative position presenting akey blank to the cutting zone.

5. The key notching device set forth in claim 4 wherein the means for tiltably mounting the carriage on the base and for propelling the same back and forth along said other path comprises a screw shaft rotatably journalled on the base and having the carriage threaded thereon.

p 6. The key notching device set forth in claim 4 wherein said cooperating means on the clamp and the base comprises a ledge on the base and a tongue on the clamp engageable under said ledge upon movement of the clamp to a position adjacent to the cutting zone to preclude tilting of the carriage whenever the clamp is in an operative position presenting a key blank to the cutting zone.

7. The key notching device set forth in claim 4 wherein the carriage has a slot therein substantially normal to its pivot axis, and the clamp has a slide block thereon received in said slot to constrain the clamp to reciprocatory motion on the carriage, toward and from the cutting zone; and further characterized by the fact that said cooperating means which interengage in the operative position of the clamp to preclude swinging of the carriage on its axis includes a tongue on the slide block projecting therefrom toward the cutting zone.

8. The key notching device set forth in claim 4 wherein the means for mounting the carriage for swinging motion and for moving the same back and forth along said other path comprises a screw shaft rotatably carried by the base and passing through a threaded hole in the carriage; and wherein the base is provided with a ledge spaced from said screw shaft and upon which the carriage rests in the operative position thereof so that the carriage is jointly supported by the screw shaft and said ledge; and further characterized by the fact that the clamp is provided with a tongue to engage under said ledge upon movement of the clamp to a position adjacent to the cutting zone to preclude tilting of the carriage out of its operative position whenever a key blank is presented to the cutting zone by the clamp.

9. The key notching device set forth in claim 10 Wherein each knob has a counterbore therein, and wherein said cooperating male and female driving elements on each screw and its knob comprises a collar fixed 0n the screw and received in the counterbore of the knob, said collar having a pin thereon eccentric to but parallel with the screw axis and projecting into a hole in the bottom of the counterbore in the knob to drivingly connect the knob with the screw.

10. In a key notching device of the type having a base, a clamp movable along a defined path toward and from a fixed cutting zone on the base to provide for adjustment of the depth of notches to be cut in a key blank secured in the clamp, and a carriage for the clamp movable back and forth along another path normal to the first designated path to impart notch indexing motion to the clamp: means for shifting the carriage back and forth along said other path, including a carriage transporting screw constrained to rotation in the base and threaded into the carriage; means for propelling the clamp back and forth along said first designated path including a clamp transporting screw constrained to rotation in the carriage and threaded into the clamp; detachable manually operable matching control knobs on said screws by which the screws may be rotated in 11 opposite directions to effect notch spacing and depth adjustment, said notches having sets of indicia delineated on their surfaces in circumferentially adjacent bands, the bands of indicia on the knob for the carriage transporting screw representing diiferent spacings for the notches to be cut in different types of key blanks, and the indicia of each band thereof on the knob for the clamp transporting screw representing notch depths to be used With one of the notch spacing bands on the knob for the carriage transporting screw; a pair of transparent plates, one fixed on the base directly over the surface of the knob for the carriage transporting screw and the other fixed on the carriage directly over the surface of the knob for the clamp transporting screw 50 that the indicia on said knobs is readily visible through the plates from above, each of said plates having a single reference line delineated thereon, said lines lying in vertical plates containing the axes of rotation of their respective knobs and being cooperable with the indicia on the knobs to indicate the rotational adjustments of the screws necessary for the cutting of notches of the proper spacing and depth in different types of key blanks; and means drivpredetermined relationship with respect to their driving elements.

References Cited in the file of this patent UNITED STATES PATENTS 1,452,308 .Miller Apr. 17, 1923 1,615,020 Loehr et al. Jan. 18, 1927 1,678,319 Blessing July 24, 1928 2,051,139 Griflith Aug. 18, 1936 2,058,719 Pigman Oct. 27, 1936 2,317,527 Herb Apr. 27, 1943 2,323,949 Vosburg July 13, 1943 2,619,853 Lange Dec. 2, 1952