Actuator of engraving machine

Abstract

The proposed actuator of engraving machine relates to decorative machining of hard materials, and can be used in arrangement of facades and monuments. A permanent magnet and a core with a pivot are concentrically fixed in an upper part of a housing. An electric coil is placed on a cylindrical frame of nonmagnetic material and can move in the axial direction in a ring gap between the core and the permanent magnet together with a pusher fixed in two circular elastic membranes, spaced in the axial direction and fixed in the housing along an external contour. A shank is fixed on the pusher under the membranes, having a central part extending through a bottom cover of the housing. It has a hollow axial opening, wherein a removable impact tool is mounted. The design is simple and reliable. Durability, accuracy and speed of engraving of the actuator are improved.

Claims

1. An actuator of an engraving machine, said actuator is associated with a control system; said actuator includes an engraving head (1) comprising: a housing (2) including: a bottom opening; a lower part containing at least two circular elastic membranes (13) having an internal contour and an external contour, said membranes (13) are vertically spaced and secured essentially to the housing (2) along the external contour; and an upper part containing a sleeve (3) enclosing: an upper support flange (32), essentially connected to said housing (2); a ring-shaped permanent magnet (4); a ring-shaped magnetic circuit washer (5) located under said permanent magnet (4), wherein said washer (5) has a top and a lower butt end lying in a radial plane; a core (6) made of material conducting magnetic flux, said core (6) is coupled with a pivot (7) located on the top of said core (6) above said permanent magnet (4); wherein said core (6) has a lower butt end lying in the radial plane of said lower butt end of the washer (5), and a ring gap (10) is arranged between the core (6) and the permanent magnet (4); a bottom cover (16) essentially closing the bottom opening, said cover (16) has a central orifice; a pusher (11) attached to said internal contour of the membranes (13), said pusher (11) has a lower part; a shank (15) secured in said lower part of the pusher (11), wherein said shank (15) is so mounted to project downward through the central orifice of said bottom cover (16), said shank (15) has a central part (17) including an axial opening (18); an electrical coil (8) having an upper portion, said coil (8) is connected to said control system, said coil (8) is wound on a cylindrical carcass (9) made of non-magnetic material and attached to said pusher (11), wherein said core (6) is mounted inside said carcass (9), and the coil (8) is capable of vertical movement such that said upper portion of the coil (8) enters or exits said ring gap (10); and an impact tool (19) mounted in said axial opening (18).

2. The actuator according to claim 1, wherein said cylindrical carcass (9) has a lower part, and said cylindrical carcass (9) is fixedly or detachably connected to said pusher (11); and said actuator further includes: a position sensor (23) secured essentially to said housing (2); a mating part (22) essentially secured on said lower part of the cylindrical carcass (9); wherein said position sensor (23) is connected to said control system, and said mating part (22) interacts with said position sensor (23) such that the position sensor (23) is capable of measuring a position of said mating part (22) in relation to said position sensor (23).

3. The actuator according to claim 1, wherein: said shank (15) has a stepped ledge with a first diameter, the stepped ledge is located above the central part (17); the central orifice of said bottom cover (16) has a second diameter; and the first diameter is greater than the second diameter thereby limiting a downward movement of the pusher (11); and said actuator further includes an adjusting screw (25) mounted on said core (6), wherein said adjusting screw (25) limits an upward movement of the pusher (11).

4. The actuator according to claim 1 wherein: said impact tool (19) is made of magnetic material; said actuator further includes a permanent magnet (20) mounted in the axial opening (18); wherein said impact tool (19) is secured by said permanent magnet (20) in the axial opening (18).

5. The actuator according to claim 4 wherein said central part (17) has a lower butt end; said impact tool (19) has a support stepped expansion (26) having an upper butt end; said actuator further includes a polymer ring gasket (27) mounted between said lower butt end of the central part (17) and said upper butt end of the support stepped expansion (26).

6. The actuator according to claim 1 wherein: said membranes (13) are configured with ring crimps; said membranes (13) are crimped by rings (29) along said internal contour; said membranes (13) are crimped by rings (30) along said external contour; and said actuator further includes spacer bushings (28) mounted on said pusher (11) between said membranes (13).

7. The actuator according to claim 1 wherein said membranes (13) are made of textile material impregnated with a Bakelite lacquer or polymer binder.

Description

BRIEF DESCRIPTION OF DRAWINGS OF THE INVENTION

(1) FIG. 1 shows a longitudinal section of the inventive engraving head;

(2) FIG. 2 shows a section of the inventive engraving head rotated at 45 degrees;

(3) FIG. 3 shows a section A-A;

(4) FIG. 4 shows a bottom view B;

(5) FIG. 5 shows an algorithm diagram for operation of the impact tool.

DETAIL DESCRIPTION OF PREFERRED EMBODIMENTS OF THE INVENTION

(6) While the invention may be susceptible to embodiment in different forms, there are shown in the drawings, and will be described in detail herein, specific embodiments of the present invention, with the understanding that the present disclosure is to be considered an exemplification of the principles of the invention, and is not intended to limit the invention to that as illustrated and described herein.

(7) In a preferred embodiment of the invention, an actuator of engraving machine comprises: an engraving head 1, including a housing 2 wherein a sleeve 3 is installed, containing a ring-shaped permanent magnet 4, a ring-shaped magnetic circuit washer 5, a core 6 (made of material conducting magnetic flux) with a pivot 7, an electrical coil 8 wound on a cylindrical frame (or carcass) 9 made of nonmagnetic material and connected to a control system, and located with a capability of movement in the axial direction in a ring gap 10 arranged between the core 6 and the ring-type permanent magnet 4, and a ring-shaped magnetic circuit of the washer 5. A bottom of the housing 2 is closed by a bottom cover 16 having a central orifice.

(8) The cylindrical frame 9 of the electrical coil 8 can be fixedly or detachably connected with a pusher 11. The pusher 11 has an open slot 12 along the entire height of the moving line of the cylindrical frame 9. The pusher 11 is fixed in two circular elastic membranes 13, which are spaced between each other in the direction of the axial line and fixed along an inner ledge by an external contour 14 in the housing 2.

(9) A shank 15 is fixed on the pusher 11 below the membranes 13. The shank 15 has a central part 17 with a hollow axial opening 18, while the central part 17 projects through the orifice of the bottom cover 16. A removable impact tool 19, being made of magnetic material, is placed in the axial opening 18 and secured there with a permanent magnet 20. In another embodiment of the inventive actuator, the shank 15 can be secured in a lower part of the pusher 11 by means of a screw-threaded attachment.

(10) On the lower part of the cylindrical frame 9, a mating part 22 of a position sensor 23 is mounted, which is installed on a plate 24, disposed in the housing 2 of the actuator and connected to the control system.

(11) The range of axial movement of the pusher 11 and parts connected thereto is limited upwards with a gap up to an adjusting screw 25, mounted on the core 6 with the pivot 7 inside the frame 9 of the electrical coil 8, and downwards with a gap in the axial direction between a stepped ledge (or a shoulder located above the central part 17) of the shank 15 made with a diameter larger than a diameter of the orifice made in the bottom 16 and the inside butt end surface of the bottom cover 16.

(12) The impact tool 19 has a support stepped expansion 26 (FIG. 2), a polymer ring gasket 27 is installed on the support stepped expansion.

(13) Between the elastic membranes 13 configured with symmetrically situated ring crimps (ridges), spacer bushings 28 are installed on the pusher 11, and outside the membranes 13 are crimped by rings 29 with rounded wedges, and also rings 30 are crimped by screws 31; wherein the membranes 13 made of textile material impregnated with a Bakelite lacquer or polymer binder with a possibility of using metal crimped membranes.

(14) The sleeve 3 has an upper support flange 32 and is fixed on the housing 2 with screws 33, and the core 6 is fixed to the sleeve 3 with a screw 34. The cover 16 is fixed on the housing 2 with screws 35.

(15) The use of the position sensor 22 of the impact tool 19 in the axial direction (which can be a Hall sensor, or, for example, optical, inductive or capacitive sensors), enables the control system (see FIG. 5) to receive actual values of impact tool positions (P), its velocity (V) and movement direction, and capture the impact moment. A detailed electric circuit and computer program are not disclosed, since they are not a subject of the invention, and are clear to those skilled in the art. For an explanation of operation of the actuator, FIG. 5 shows a flowchart of the algorithm for operation of the impact tool, through calculating a velocity by a method for measuring transmission time of a fixed path (V=Sconst/T).

(16) The availability of these data enables the control system to monitor and control the power of impact, to minimize the amplitude value of the impact mechanism, to increase the engraving speed, to control directly and stabilize the gap between the impact mechanism and processed surface without applying additional hardware and/or software and hardware.

(17) As the velocity (V) is a ratio of the passed path (S) for the time (T), then the velocity can be calculated by two methods:

(18) 1. Calculating the passed path for a certain time: V=S/Tconst.

(19) 2. Calculating time of the passed fixed path V=Sconst/T.

(20) The choice of calculating method is determined by hardware and software capabilities of the control system.

(21) The passed path (S) is calculated as the position difference of the impact mechanism obtained between the measurement intervals: S=P.sub.0P.sub.1. The obtained difference sign indicates the movement direction.

(22) In a general case, the passed path is a number, determined by the used hardware and software. The used hardware and software determine the accuracy of position measurement and the range of possible values.

(23) Considering that the implementation of the position measurement in the engraving mechanism with values more precisely than a few micrometers is technically difficult and unreasonably expensive, and the fact that the measured movement in the engraving mechanism differs with a relative small amplitude (from fractions of millimeter to several millimeters), and the possibility of accurate time measurement are hundreds and thousands of megahertz, it is better to perform calculations of the velocity by the time measurement method of the passed fixed path (V=Sconst/T).

(24) Initially, the actuator's position is set by the control system, based on a signal received from the Hall sensor. In operation, based on an actual stop position of the impact tool on the processed surface, the actuator's position is corrected on the basis of a difference of the actual location of the impact point and the predetermined location.

(25) The instant inventor has developed a software program and used it to control the inventive actuator.