METHOD AND APPARATUS FOR ENGRAVING A MARK ON PLANE OR SLIGHTLY CURVED SURFACES

Abstract: Method and apparatus for engraving on a surface (7) by a rotating mill a mark, a wording or the like formed of a series of numbers and/or letters and/or symbols and set in a computer or controller (1) provided with a keyboard (5) and a display (8). The method provides means for transmitting in a sequence electrical signals containing the information of the form and size of each letter, number or symbol forming the mark, and signals controlling the operation of an electro-mechanical engraving apparatus (2) including a moving assembly supporting a little, motor driven rotating mill (3, 3a) and being installed within a case by supporting means causing it to be moved in two directions (X-X) and (Y-Y) perpendicular to each other and to the axis (Z-Z) of rotation of the tool (3, 3a) that is able to shift with respect to its axis of rotation (Z-Z) so as to allow said mark to be engraved type by type.

Description: Method and apparatus for engraving a mark on " plane or slightly curved surfaces. 5 Description The present invention relates to a method and a apparatus for engraving in indelible way type by type mark formed of numbers and/or letters and/or symbols on C a plane or slightly curved surface in order to mak personal belongings the marked thing or article, e.g. car or the like for ant 1- the ft or iάenti f icat io purposes . Systems and apparatus for similar purposes are already 5 known. In the known and very diffused appara s the marking i cairie out by means of a device delivering a strong je of a mixture of compressed air and abra-.vc granule which are projected on a limited area of the surface ro 0 he masked through a mask almost put into contact wit said surface. Slits having a form complementary to tha of the numbers, letters or symbols to be marked ar provided in the mask. In some cases said mask is forme of el e ent s which can be a ranged in order to form one 5 of the numbers , letters or symbols of the wording to b p ov id e . Such known apparatus are used in particular for markin glasses or met allic surfaces. Said apparat s have the drawback of regui ring long and labor ious operations for preparing and assembling the masks. Furthermore they have the disadvantage to pollute the environment of operation with the dust unavoidably escaping from the apparatus and to dirty surrounding parts, things or persons . Another type of apparatus provides for the marking with the aid of a warm punching system. Said system is ada'pted for the marking of surfaces consisting of plastic material or having a covering of plastic material or surfaces of wood or other similar mater als . These apparatus require a long time for preparing and arrange the punching device applying the personal wording -on the surface ,and are limited in their use capabi 1 i ties . To attain the same purpose the present invention provides an operative method and an apparatus for ca rying out this method in which the elements forming the wording to be marked, i.e. numbers, letters or symbols , are set in a computer or controller provided with a keyboard and a isplay, means being provided that for each type or element of the mark generates an electrical signal containing the information of the form and the size of each type and the sequence of said types. Said signals are transferred to an electro¬ mechanical apparatus with a rotating mill for engraving the mark type by type on the surface . The marking essentially begins just after the wording of the mark being ar anged into the computer , operation that requires only a short time. It is also provided to use a controller with means for printing and storing the applied wording complete with all personal in format ion regarding the user availing himself of this service . The present invention essentially provides the use of a cont oller or computer associated to an elect romechanical apparat s . The controller or computer is provided with a keyboard for setting the wording of the mack, a display of the setting data, an eventual printer, and means for sto ing said printed mark and the personal data of the owner of the marked thing, in particular a car. Of course, the method and the appa atus can be used for other purposes with suitable a dap tat ion . Said controller or computer is arranged to supply, after a number, a letter or a symbol being set by the respective button of the keyboard and after the setting of information relative to the specific characteristics of each type, electrical signals to the electro¬ mechanical apparatus which is arranged to translate said signal of predetermined duration into a rotation movement of the rotating tool, in part icular a mill or the ' like, into a shift towards an operative or non- ope ative position of the head of said tool and into O IGI separated or simultaneous movements of said head in two directions perpendicular to each other and to the direction of the rotation axis of said tool so that the rotating head of the tool is capable to engrave the surface to be marked reproducing type by type the numbers and/or letters and/or symbols of the mark. These and other features of the invention will be more readily apparent from the following descr iption of a prefer ed embodiment of the apparatus of the present invention with reference to the accompan ing drawing , in vh ich ; Fig. 1 is a perspective schematic view of the complete apparatus according to the present invention ; Fig. 2 is the schematic cross-section of the electro¬ mechanical apparatus taken along the line A-A of Fig. 3, the outer case being eliminated; Fig. 3 is a top view of the apparatus of Fig. 1; Fig. 4 is a side, longitudinal , partially cut-away view of the apparatus , the side supporting wall being eliminated; F g. 5 shows the block diagram of the controller or ccmαuter; Fig. 6 is the block diagram of the printed circuit board of the microcomputer of Fig. 5; Fig. 7 shows the detail of a circuit controlling the shift of the tool along the axis x and y, respectively; Fig. 8 shows the detail of a circuit of the contact sensor , F_.g. 9 shews the detail of the circuit regarding the control of operation; Fig. 10 shows an example of the reproduction of a type of the mark; and Fig. 11 is a flow chart of the machine With reference to F g. 1 the controller or computer is generally des ignated by 1 and the electro-mechanical apparatus by 2, said apparatus translating the signals supplied by the unit 1 into movements of the tool 3 having an engraving rotating head 3a. Said units 1 and 2 are connected to each other by means of a cable 4. In the l 1 lustrated embodiment the unit 1 is provided with a keyboard 5 of the conventional type, i.e. having control or function buttons 6A, 6B, 6C, and 6D and buttons 6 for the setting of the wording or mark to be engraved on the thing to be marked, in particular the surface of a plane or slightly curved wall 7. The apparatus 1 is also provided with a display 8 showing the numbers , letters or symbols of the mark which has been set by the buttons 6. By means of a solution known by itself a means is provided in the apparatus for printing the worαing of the mark on at least a strip of paper 9 and for further adding beside each mark the personal data of the user availing himself of the se vice , said data being also stored into the computer for statistic and/or research pu poses . The appa atus 1 is made using the technology of the art and is capable to supply electrical control signals which are compatible with the technology of the appara t s . 2. It should be appreciated that the scope of the present invention is that the head 3a of the rotating tool 3 is caused to move and to engrave type by type on the surface 7 any type of the wording or mark according to the succession of types set into the computer , duly spacing the types apart from one another . This is accomplished for the fact that the tool 3, 3a under operation is caused to shift in a plane along two axis X—Y perpendicular to each other. Said shifts can be carried out successively or at the same time in order to engrave the curved portions of the types as better illustrated herebelow. Furthermor , the tool 3, 3a is either caused to approach the surface 7 to be marked at a given time and for a predetermined period of time or to move away from it, means being also provided varying the depth of the cut. The device 2 consists of a case 10 provided with air openings 11 and tapered at its front portion 10a which is closed by a plane wall 12 provided with a longitudinal slit 14 the lenght of which is eq ' ual to the max imum lenght F of the succes ion of types forming the mark. The height of such a slit 14 is a little higher than the height E of the types forming said mark. The rotating tool 3, 3a projects from said slit 14. The front wall 12 of the case 10 is surrounded by a side protection wall 13 extending outwards and being parallel to the axis of rotation Z-Z of the tool 3, 3a. The outward ex tens ion of said wall is such that the head 3a is located in a retracted position with respect to the edge 13a of the wall 13 so that said tool is protected from a collision during the shifting of the device 2. Referring now in particular to the device 2 of Figs. 2 to 4, a central moving assembly generally designated by 15 provides a motor 16 driving the tool 3, 3a and installed on a case 17 housing the gearbox not shown in detail as it is of conventional type. The case 17 is provided with an enlarged head 17a which projects partially from the case 17 and forms an edge or shoulder 18. Said head is provided with a hole 19 in which the spindle 20 supporting the tool 3, 3a is passed. The case 17 is supported so as to shift with respect to the rotation axis Z-Z of the tool 3, 3a within a tubular guide means 21 provided with flanges 21a diametrally opposite to each other and projecting towards the longitudinal walls of the case 10 while facing the shoulder 18 of the head 17a. Pressure springs 22 are placed between said flanges 21a and said shoulder 18. Housed in the case 17 is an elect omagnet (not shown ) causing the case 17 with its head 17a and the whole assembly , in particular the tool 3, 3a, ' to be returned to the non-operative posi tion and to be locked in said position until a releasing signal is fed to the ele tromagnet . Afterwards the springs 22 cause the case to shift and to press the head 17a against the surface 7 to be marked, while another signal switches on the motor 16 and still another signal causes the head to move along the surface 7 to be milled with a predetermined depth which can be set by an already known means associated to the spindle 20. The assembly 15 is hanged by the flanges 21a of the guiding support 21 at the lower ends of two parallel arms 23A, 23B. The arm 23A at its upper end is provided with a longitudinal , inside threaded hole in which a longitudinal threaded shaft 55 is screwed which is supported freely rotating about its axis by a_ pair of transversal walls 24A, 24B of the case 10 which are parallel to each other. The threaded shaft 55 (Fig. 3) is connected to a driving motor 25 by a suitable gearbox . The arm 23B is supported by a toothed rod 26 provided with end support means 26a, 26b of cylindrical form which in turn are supported by the wall 24A, 24B so as to be rotated . together with the rod 26 about their axis by a motor 27. P ovided in the upper end of the arm 23B is a long i udinal hole 29 formed so as to allow the toothed rod 26 to freely shift within said hole. A plate 28 extending towards the wall 24A with an arm 30 is fas ened to the inside wall of the arm 23B near the upper end ther of . The arm 30 supports by its portion 30a a shaft 31 which is parallel to the axis Y and on which a toothed wheel 32 engaging the toothed rod 26 is j our nailed . The shaft 31 is connected by a suitable gear means to the cursor of a potentiometer generally designated by the block 33. When the motor 25 is driven the threaded shaft 55 rotates and engages the threaded hole, thus acting as lead screw so that the whole linked parallelogram assembly formed of the two arms 23A, 23B with the assembly 15 hanged, at their lower ends by the flanges 21 is caused to move forwards or backwards . In this way- the whole assembly can shift in the direction of the axis X according to the direct ion of rotation of the shaft of the motor 25, thus moving parallely to the longitudinal axis of the slit 14 of the case 10. Such shifts in said direction are sensed by the toothed wheel 32 engaging the toothed rod 26 and then rotating by an angle represen ing- the displacement along the axis X, said angle being detected by the potentiometer 33 supplying time by tyme the in format ion of the working pos i tion of the head 3a of the tool 3 along said axis X. On the ground of such an i n format ion the controller (1) will either establish the path to be engraved or the non-operative condition by driving the assembly in the case 17 having the function of causing the tool 3 to be approached or moved away from the surface 7 to be marked . On the contrary , the maximum displacement of the head 3a of the tool 3 is designated by E in Fig. 2. Said άi splace ent , in case of the particular above mentioned purpose of the invention , i.e. the marking of parts of a car or the like, is at the most about 6 mm, i.e. a very low amount. Ther fore , said displacement is carried out by means of an oscillation of the hanged parallelogram assembl . To this end the motor 27 transmits a rotation to the rod 26 by the cylindrical support 26a of said rod 26 located at the end thereof near to said motor 27. As a result the rod 26 rotates with a reduced speed by an angle equal at the most to about 5° in the case of the illustrated embodiment . Such a rotation causes the rod 26 together with the arm 233 to rotate about its axis and the tool 3, 3a- to move with respect to the central position shown in Fig. 2 to one side or the other side so that the head 17a of the assembly 17 can reach at the most one of the two limit positions indicated by dashed lines (Fig. 2) . The cy liner ical support 26b opposite to the rod 26 is connected to a potentiometer 34 control ling the shifts of the tool in the direction of the axis Y and providing the information of the displacement to the con roller I to which the signals from the poten iometers 33 and 34 are fed under the form of a d.c. voltage + V with r specc to ground. It is to be noted that in the illustrated embodiment the maxTmum shift F max in the direction of the axis X is shown in Fig. 3, said shift being equal to about 7 ' 5 cm in the illustrated embodiment . The operation of the apparatus 1 will be now briefly described herebelow . Referring to the Figs. 5 to 11 a general block diagram is shown in Fig. 5. In said block diagram the power supply is designated by 35 and consists of a circuit taking a suitable voltage and generating the voltages necessary for the operation of the circuits of the apparatus . The power supply 35 is designed so as to . supply the required currents at any output at the desired voltage ■ and is protected from eventual short ci cuits which might result. Designated by 36 is a block or a card of the microcomputer (control process unit). Said card represents the heart of the system as all information from the operator to the machine and viceversa from the machine to the operator or to the various actuators come into this card. The task of the- microcomputer is that of guiding the operator to let in data to be marked in a correct way. The dialogue card 36 operator is held through the a lphar.-imeric keyboard 5 by which the ope ator lets in data. Messages are given to the ope ator and the echo testing of the let in data is carried out by an alphar.umer ic display 8. At the end of the let in phase the program routing in said card 36 wild provide for rans forming data in a format compatible to the input /output unit and will supply to the output interface 37 the data succession requested by the operator . Furthermore the program controls time by time the actuators by means of a location control by the potentiometers 33, 34 associated to the horizontal feed motor 25 and to the vertical feed motor 27, respecti vel y . s Designated by 38 in the block diagram of Fig; 5 is a sensor located in a suitable position and sensing the contact of the head 3a of the tool 3 with the wall 7 to ' be marked. Fig. 6 shows the block diagram of the card 36 (CPU) of Fig. 5. A microcomputer , e.g. type INTEL 8085 with a clock of 6136 MHz formed by the block 39, is used for this apparatus . The microcomputer 39 takes from a ROM 40 the instructions to be per formed (program) and uses for counting purposes and for storing data a RAM 41. The ROM 40 is a read only memory from which it is only possible to take data. The data of the RAM 41 can be written and taken at any moment . The dialogue between the card 36 of the microcomputer 39 and the operator is performed by an address bus 42 and a data bus 43 along which data are exchanged. The data bus 43 is bidirectional as it provides the data t ansfer both towards and from the microcomputer (CPU) The address bus 42 is unidirectional as only the microcomputer 39 can address such a bus. In order to establish a connection in "parallel" on the data bus 43 it is absolutely necessary that the peripheral units not involved in the data exchange with the CPU 39 does not have any influence on the data bus 43, i.e. they should provide (the selected peripheral units excepted) on the data bus _43 a state of high imoedance. This is achieved by providing each electronic unit connected to a data bus with a control line receiving signals that in the high state cause the high impedance to be provided and in the low state cause the data bus 43 to be engaged by the corresponding unit. The management of said control lines is made by a decoder 44 that according to the addressing provides a low state on only one of the control lines. Fig. 7 shows the detail of the output interface 37 concerning the control circuit of the feed motor 25 of the axis X. An identical circuit shown only dashed is provided for the motor 27. The motors 25 and 27 are controlled by the card 36 of the CPU 39 caus ing according to their position the rotation in either the clockwise or the counterc lo ' ckwise direction . The relative position is sensed by supplying to the associated potentiom ter 33 or 34 a stabilized voltage and by reading the output signal of the cor responding potent iometer . Thus a biunivocal correspondance between the read voltage and the position of the motor or rather the tool 3, 3a in the engraving phase is provided . The analog signal has to be converted into a digital signal for the microcomputer 39, the conversion being carried out by the block 45. Fig. 8 is the circuit diagram of the contact sensor 38; and Fig. 9 is the circuit diagram of the actuating device. Fig.10 shows by way of example an embodiment of the letter D. Fig.11 is the flow chart of the machine. The block 46 indicates the switching on, the block 47 indicates the peripheral init ialization , the block 48 indicates the d i sab ling of the engraving tool, the block 49 is the request of let in data by the operato , the block 50 indicates the engraving phase, the block 51 indicates the let in of new data, the block 52 indicates that the tool 3, 3a is in the ope ative condition, the block 53 indicates that the tool 3, 3a is in operation and the block 54 indicates the end of the operation cycle.

Claims: Claims 1. Method for engraving a mark on a plane or slightly curved surface (7), in particular of a car or the like, 5 wherein the engraving of the mark formed of letters and/or numbers and/or symbols is carried out type by type by means of a head of a tool (3, 3a) such as a mill or the like rotating about the axis (Z), said tool (3, 3a) being associated to a motor (16) causing it to. 10 rotate in only one direction and to springs and to an electromagnet which cause the support of the tool to be fed or retracted along the axis (Z) starting from a rest position and viceversa , said tool being part of an assembly (15) including the motor (16) and means for ' 15 transmitting the movement to the tool (3, 3a), the means setting the position of the assembly (15) being placed within a supporting framework so as to carry out separa ely or at the same time shifts parallel to an axis (X) and an axis (Y) , respectively, said axis being 20 perpendicular to each other and to the axis (Z), said means being controlled by respective motors (25) and (27) operating in both directions, a sensor (38) being provided in said assembly so as to supply the information if the head (3a) of the tool (3) is in touch 25 or not with the surface (7) to be marked, a controller or a microcomputer (1) being used in said method and including : means (5) for setting the series of type 1 forming the mark, means (8) for displaying the set mark and, if requested , means for printing the set mark on a piece of paper (9) and/or for storing it by adding eventual personal data of the user, said controller (1) further including : means for storing the i formation relative to the form and the size of the types, means for converting such information into electrical signals , means for controlling the beginning and the end of the engraving operation under the control of set means, means for taking successively from the -memory the information relative to the form and the size of each type and to the sequence of setting, and means for converting said signals into control signals able to switch on or off the electro-mechanical device of an apparatus (2) connected via cable (4) to the controller (1) in order to cause the tool (3, 3a) to carry out the .-.equested movements at the desired time and for the p edetermined period of time by operating the motors ( 15 , 25 and 27) . 2. Apparatus for carrying out the method of claim 1, including a controller or computer (1) connected via cable (4) to an electro-mechanical engraving apparatus (2) comprising a tool (3) provided with an engraving head (3a) such as a mill or the like and rotating about its axis (Z) and housed within a case (10) having an ■ essentially rectangular cross section and provided- with a front wall (12) in which a longitudinal slit (14) is providec which is parallel to the axis (X) and perpendicular to the axis (Z), said slit having a height a little higher than that of the types to be engraved on the surface (7) and a' length a little longer than that of a mark including the maximum number al lowable of types which is compatible with the setting of the apparatus (1), a peripheral shielding wall (13), 'projecting to such an extent so as to prevent the tool (3, 3a) from protruding from the edge (13a) thereof , being provided around said slit (14) from which the tool (3, 3a) projects under non-operative conditions, the assembly (15) supporting the tool (3, 3a) being placed in the case (10) and including a driving motor .(16) which is integral with a tubular guiding support (21) provided with longitudinal flanges (21a) parallel to the axis (X), said support (21) housing a case (17) including the gearbox connecting the motor (16) to the spindle (20) which supports the tool (3, 3a) in an axially adj us table way, pressure springs (22) pushing outwards the case (17,17a) along with the tool (3, 3a) being interposed between the two flanges (21a) of the support (21) and the head (17a) of the case (17), while an electromagnet placed in the case (17) maintains the case (17 ) under retracted condition, said assembly (15) being carried by a supporting means able to move it in the direction of the axis (X) and/or (Y) essentially on a plane perpendicular to the axis (Z) -so that the working head (3a) of the tool (3) can follow a path allowing the selected type to be engraved on the surface (7) under the control of signals coming via cable (4) from the controller (1) according to the setting of the 5 various types of the mark to be reproduced , said controller (1) including.- a keyboard (5) with control buttons (6A, 6B, ...) and setting or function buttons (6), a display of the working (8), means for printing, if requested, the wording on a strip of paper (9), and C further including memory means, cards and devices to carry out the program for the pred termined operative cycle of the tool (3, 3a). 3. Apparatus according to claim 2, wherein the assembly 15 supporting the tool (3, 3a) by the flanges (21a) is 5 hanged by linked rods having axis parallel to the axis (X) at the lower ends of two arms (23A, 233) parallel to each other, and the arm (23A) at its upper end is provided with an inside threaded hole having an axis parallel to the axis (X) and in which a longitudinal 0 threaded shaft (55) is passed that is suppor ed at its ends by a pair of transversal inside walls (24A, 24B) of the case (10) and is connected at the nearest end with respect to the wall (24A) to a driving motor (25) which rotates the shaft (55) in both directions, the other 5 supporting arm (23) at its upper end has a transversal hole (29) having a cross section complementary to the outer shape of a longitudinal toothed rod (26) supported at its ends by cylindrical coaxial supports (26a, 26b) so that said rod can freely shift within said hole (29) and can be rotated about its axis by a motor (27) rotating in both directions so that the rotation of said rod (26) about its axis causes the rotat ion of the arm (233) integral with the rod in a plane perpendicular to the axis (Z) as well as the rotat ion of the assembly (15) and of the arm (2-3A) so that the head (3a) of the tool (3) is caused to move essentially parallel to the axis (Y) . 4. Apparatus according to claim 2 and 3, wherein the arm (2.33) supported by the toothed rod (26) is made integral with a plate (28) supporting an arm (30) carrying in turn by means of a support (30a) a ransve rsal shaft (31) on which a wheel (32) engaging the toothed rod (26) is j ournal led , said arm (30) taking from the displacement of the wheel (32) along the toothed rod (2f>ι the in format ion of the displacement of the tool (3, 3a) m the direction of the axis (X) by means of an amperometer device (33), while the cylindrical end (26b) of the toothed rod (26) is connected to the cursor of a potentiometer (34) to sense the displacement of the tool (3, 3a) with respect to the axis (Y) as a function of the rotation angle of the rod (26) about its axis.

Inventors: CACCIOTTI ANGELO, CACCIOTTI, ANGELO
Applicants: GRANDI SERVIZI SPA, GRANDI SERVIZI S.P.A.
Application year: 1986
Main classification: B44B3
IPC codes: B44B3, B44C1