TOCCHET, Gianni (Via Gramsci 11, Cappella Maggiore, I-31012, IT)
| C L A I M S 1 . A method for producing key blanks for cylinder locks, characterised by: - forming with a slot miller (8), in at least one surface of a sheet metal piece (2) of substantially constant th ickness provided with locators (4) for its precise positioning on said work table (24), those grooves (16) which define the profile of the key blank (14), - laser cutting the shape of the key blan k to be obta ined , but with the exclusion at least of its tip, such that the grooves (16) formed in th is manner occupy the shank (12) of said key blank (14), - subjecting said shape to brushing in order to remove the burrs caused by the laser cut, - separating the key blank (14) obtained in this manner from said sheet metal piece (2) by cutting with said slot m iller through all those points at which said key blank (14) is joined to the remaining part of the sheet metal piece (2). 2. A method as claimed in claim 1 , characterised by stabilizing the position of the sheet metal piece on the work table (24) by engaging locators present in said sheet metal piece with reference elements present in said work table. 3. A method as claimed in claim 2, characterised by stabilizing the position of the sheet metal piece (2) on the work table by engaging holes (4) provided in said sheet metal piece with reference elements present in said work table. 4. A m eth od as cl a i m ed i n o n e or m ore of th e preced i n g cl a i m s , characterised by laser cutting the shape of the key blank to be obtained, with the exclusion only of its tip. 5. A machine for implementing the method in accordance with one or more of the preceding claims, characterised by comprising, on a base (22): a work table (24) on which a sheet metal piece (2) of substantially constant thickness is placed in a well defined position, and from which at least one key blank (14) is to be obtained, a first carriage (26) movable relative to said base (22) in a first direction of approach to said work table (24) and of withdrawal therefrom, means (28) for controlledly moving said first carriage (26) relative to said base (22), a second carriage (30) movable relative to said first carriage (26) in a second direction parallel to said work table (24) and perpendicular to said first direction, means (32) for controlledly moving said second carriage (30) relative to said first carriage (26), a milling head (6) mounted on said second carriage (30) and provided both with rotating means for the brush and with means for its movement parallel to said tool, which consists of a slot miller, a laser cutting head (10), mounted on said second carriage (30), a brushing head (20) mounted on said second carriage (30) and provided both with rotating means for the brush and with means for its movement in the d i rection of approach to sa id work ta bl e (24) and of withd rawal therefrom, a unit for controlling said movement means for said first carriage, for said second carriage, for said milling head and for said brushing head. |
The present invention relates to a method for producing key blanks for cylinder locks.
Locks are known comprising an operating cylinder for a bolt, and a key insertable into the cylinder and able to rotate it in order to operate the bolt.
The key can be in serted into the lock cyl i nder on ly if its profi le corresponds to the cross-section through the slot provided in the cylinder, and is able to rotate the cylinder only if the key bitting pattern corresponds to the cylinder code.
The lock security is related to the large number of profiles which exist for keys, and the large number of possible codes, and hence the very low probability of being able to operate a lock with a key intended to operate a different lock.
There currently exist tens of thousands of profiles for key blan ks, which then have to be encoded to be able to operate a given lock. It follows that any key duplication centre special ized in duplicating a key blank, i .e. in transforming a key blank into a bitted key suitable for operating a given lock, must have available a vast assortment of key blan ks with the most varied profiles, in order to be able to satisfy the different user requirements.
These req u irements mostly relate to a l im ited nu m ber of profiles associated with the most widely used keys, but can sometimes relate to keys with a l ittle-used special profi le . I n th is case it is not only rare that the duplication centre itself has the required key blank for that particular duplication work, but it is also rare that the key blank producer keeps such a rarely required special profile in stock. When such a case occu rs, i .e. when the dupl ication centre has to dupl icate a particu l ar key for wh ich th e key bl an k is not ava i lable , the duplication centre applies to the manufacturer who, before producing that profile, waits to receive further orders to overall justify the equipment tooling cost. This can result in a lengthy waiting period, often incompatible with the requirements of the user who, when requiring a key to be duplicated, very often needs it to satisfy an immediate contingent necessity.
An object of the invention is to solve the problem of producing key blanks with particularly unusual profiles, without having to sustain the costs currently incurred for equipping a production line, but by using simple equipment which could theoretically even be installed at duplication centres.
This and other objects which will be apparent from the ensuing description are attained, according to the invention, by a method for producing key blanks for cylinder locks as described in claim 1 .
The present invention is further clarified hereinafter with reference to the accompanying drawings, in which:
Figure 1 is a perspective view of a sheet metal piece being worked with a slot miller, which produces the slots forming the profile of the key blank,
Figure 2 is a perspect ive view of th e sa m e sh eet m eta l p iece d u ri ng subsequent laser cutting of the key blank shape,
Figure 3 is a perspective view of the same sheet metal piece in the final mil l ing mach ine intervention stage for finally separating the key blank from the remaining sheet metal piece,
Figure 4 shows a key blank shaped from the sheet metal piece, and Figure 5 is a schematic plan view showing a machine for implementing the method of the invention.
As can be seen from the figures, the method of the invention starts from a sheet metal piece 2 of substantially constant thickness, as generally required for producing a key blank, and provided with locators 4 for its precise position ing on the work table of a combined mach ine. Th is comprises an operating head 6 for a slot miller 8 and a laser cutting head 1 0, these being positionable in turn above the sheet metal piece 2 fixed onto the mach ine work table. The locators 4 can consist of the edges of the sheet metal piece 2 if of regular shape, or holes, through which the piece can be fixed to the work table.
After the sheet metal piece 2 has been correctly secured to the work table, it is subjected to milling by the slot miller 8, which forms, in that portion of the sheet metal piece to form the shank 1 2 of the key blank 14, a series of parallel grooves 1 6 which overall define the profile of the key blank 14 (Figure 1 ). These grooves 16 can be provided on one or both of the surfaces of the sheet metal piece 2, according to the key profile to be obtained.
Following this operation the milling head 6 is withdrawn and replaced by the laser head 10, which is made to cut the key shape from the sheet metal piece (Figure 2).
The laser cut is not continuous, but presents at least one interruption at the key tip, where the th ickness variation due to the presence of the grooves would not allow correct action of the laser beam 18.
After the laser head 10 has operated, it is withdrawn and in its place a brushing head 20 is positioned to remove from the sheet metal piece 2 those burrs inevitably caused by the laser cut. The brush ing head 20 is then withdrawn and the m ill ing head 6 is repositioned in its place to cut through the short piece or pieces which join the key blank 14 to the remaining part of the sheet metal piece 2.
The key blank 14 obtained in this manner is then subjected to usual deburring operations to complete the cycle, wh ich is preferably controlled automatically by a control unit on the basis of different operating programmes for each type of key blank.
From the aforegoing it is apparent that the method of the invention is particularly advantageous in that:
- it does not require the equipping of special machines, but uses very simple traditional machine tools, which can be programme-controlled and can economically produce even a single key profile,
- it is con seq uently i m med iately abl e to satisfy any req u i rement of a duplication centre, or even of the user if the equipment is installed thereat.
To im pl ement the aforedescri bed method the invention uses an automatic machine, schematically illustrated in Figure 5.
This machine comprises a base 22 and a work table 24, which is rigid with the base 22 and to wh ich the sheet metal piece 2 can be fixed in a properly defined position.
On the base 22 a first carriage is mounted movable relative to the base in the direction of approach to the work table 24 and withdrawal therefrom . An electric motor 28, preferably of stepping type, controlled by a control unit (not shown in the drawings) drives the carriage 26 along the base 22 in the two directions.
On the first carriage 26 a second carriage 30 is mounted movable relative to the first carriage 26 in a direction parallel to the work table and perpendicular to that in which the first carriage moves. The second carriage is driven by a stepping motor 32 controlled by the same control unit.
The milling head 6, the laser cutting head 10 and the brushing head 20 are mounted on the second carriage 30; of these, at least the milling head and the brushing head are provided with means, controlled by the same control unit, for moving them in a direction perpendicular to the work table.
The coordinated action of these three heads, under the control of the control u n it for the entire operating cycle, enabl es those interventions characteristic of the invention to be carried out on the sheet metal piece 2 locked on the work table 24, with resultant production of the key blank having the desired profile.
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