US2836059A - Arrangement for recording the results of the supersonic examination of metal parts - Google Patents

Description

May 27, 1958 mum-n E TAL 2,836,059 ARRANGEMENT FOR RECORDING THE RESULTS OF THE SUPERSONIC EXAMINATION OF METAL PARTS Filed Oct. 20, 1984 5 Sheets-Sheet l LOUIS BEAUJARD VLADIMIR HUSAREK 9 ANDRE VASSET INVENTORS 7 AGENT y 1958 L. BEAUJARD ETAL ARRANGEMENT FOR RECORDING THE RESULTS OF THE SUPERSONIC EXAMINATION 0F METAL PARTS Filed Oct. 20, 1954 5 Sheets-Sheet 2 May 27, 1958 L. BEAUJARD EIAL 2,836,059 ARRANGEMENT FOR RECORDING THE RESULTS OF THE SUPERSONIC EXAMINATION 0F METAL PARTS Filed Oct. 20, 1954 5 Sheets-Sheet 3 Fig.3.

May 27, 1958 L. BEAUJARD ETAL ARRANGEMENT FOR RECORDING THE RESULTS OF THE SUPERSONIC'EXAMINATION 0F METAL PARTS 5 Sheets-Sheet 4 Filed Oct. 20. 1954 LOUIS BEAUJARD VLADIMIR ,HUSAREK ANDRE VASSET INVENTORS AGENT ET AL M y 7, 1958 1.. BEAUJARD 2,836,059

ARRANGEMENT FOR RECORDING THE RESULTS OF THE SUPERSONIC EXAMINATION OF METAL PARTS 5 She ets-Sheet 5 Filed Oct. 20, 1954 mnmnmucmmnmanuun d l M N F aw V 46 N M a United States Patent 91 ARRANGEMENT FOR RECORDING THE RESULTS it THE SUPERSUNK EXAMINATION OF METAL PARTS Louis lieaujard, Saint Germain en Laye, Vladimir Husarelr, Paris, and Andre Vasset, Bois-Colonibes, France, assignors to institut de Recherches de la Siderurgie, Saint-Germain-en-Laye, France Application Gctoher 20, 1954, Serial No. 463,443

Claims priority, appiicatiou Germany October 28, 1953 1 Claim. (Cl. 73-67.8)

Arrangements for recording the results of supersonic examination of metal parts are known. For instance, in some of the said prior arrangements, the elastic vibrations of the metal applied to the receiving quartz and transformed by the latter into electric pulses are amplified. The alternating voltage obtained is fed to the vertical deflecting plates of an oscillograph so as to obtain a record of the pips. Since the photographic recording of such pips is diflicult, although possible, a modification of the electronic wiring diagram of the arrangement has been provided so as to allow an easier recording. The alternating voltage which is generally applied to the vertical deflecting plates is applied instead to the control grid of the electronic gun. The grid acts as a valve and if it is brought to a negative voltage with reference to the cathode of the oscillograph, the electrons are arrested and do not reach the screen. If the control grid assumes a lesser negative voltage with reference to the cathode, the electrons pass through it and form a luminous spot on the screen. A negative voltage which just stops the electrons should thus be applied permanently to the control grid, and any positive voltage transmitted to the latter by the vibration-receiving quartz will then release the electrons and all the more so when the said voltage is higher and the usual pips are thus transformed into luminous spots.

When examining the structure of elongated members such as a rail, for instance, it is sufiicient to unwind a photographic film behind an objective while the testing means is caused to move over the rail. The defects of the rail or the like member are thus recorded with their intensity and accurate location.

However, this arrangement shows various drawbacks.

It is necessary to develop the film after the examinationhas been finished, which leads to the transportation of cumbersome photographic auxiliaries. Furthermore, it is impossible to provide for the recording of the defects as soon as they are detected. Lastly, it is possible to provide for the recording of the defects only in a single direction.

The object of our invention is to remove these drawbacks by producing a recording system requiring no photographic auxiliaries, while it allows ascertaining the presence of the defects as soon as they have been detected and recording them throughout the outer surface of the metal member to be examined.

To this end, our invention has more specifically for its object an arrangement for recording the results of supersonic examination of metal members, the said arrangement including means for testing the member to be examined, the said means being connected with responsive means incorporating a cathode ray oscillograph, which latter is designed in a manner such that at least one small-sized photo-cell may be applied against the screen while the leads fed by said cell energize the means indicating the defects of the member to be examined.

According to a further feature of our invention, the

2,836,059 Patented May 27, 1958 testing means is constituted by a piezo-electric quartz contained inside a liquid-filled chamber, the periphery of which assumes substantially the shape of a tire for vehicle wheels with a view to obtaining through a rolling movement of said chamber and without any sliding thereof, a substantial contacting area between it and the member to be examined.

According to a still further feature of our invention, the photocell is designed so that it may be shifted in parallelism with the screen and occupy the location corresponding to the area of the defective section to be examined.

According to a modification of our invention, a plurality of photo-cells are carried in contacting relationship with the screen.

A further feature of our invention is constituted by means recording the defects of the member that is being examined, formed by a stylus connected through an amplifier with one of the terminals of the photocell and running over a sheet of special recording material which sheet, connected with the other terminal of the photocell, is coated with an insulating material the color of which is different from that of its own surface so that the said insulating material is perforated whenever a difference in potential appears across it, whereby the surface of the sheet appears to view in register with the location of the stylus at the moment of the perforation.

According toa still further feature of our invention, means constituted by an acoustic alarm device is provided to indicate the defects of the member to be examined.

According to yet another object of our invention, this means indicating the defects of the member to he examined is constituted by a stylus running on a sheet of special material associated with an acoustic alarm device.

In order to allow our invention to be readily understood, We will now disclose by way of example and by no means in a limiting sense, a preferred embodiment of our invention, illustrated diagrammatically in accompanying drawings, wherein:

Fig. 1 is a diagrammatic perspective view of the whole examining arrangement;

Fig. 2 is a wiring diagram thereof;

Fig. 3 is a vertical cross-section of a transducer according to our invention;

Fig. 4 is a front view of the said transducer;

Fig. 5 is a perspective view of the system of photocells associated with the examining apparatus incorporating a cathode ray oscillograph;

Fig. 6 is a partial perspective View on a larger scale of the said arrangement of photocells, showing the detail of the mounting of said cells;

Fig. 7 illustrates diagrammatically the procedure of the examination made of an elongated flat member and the record of the results obtained.

Turning to Fig. l, the supersonic sounding arrangement includes chiefly transducer 1 which, in the case illustrated, is carried by the metal member 2 of which it is desired to find the defect. The transducer is electrically connected with a supersonic detecting apparatus 3 of a known design, such as described in U. S. Patent No. 2,280,226, of April 21, 1942. This apparatus sends electric pulses to the transducer 1 where they are changed into mechanical vibrations for producing ultra-sonic waves. These waves, after having been reflected by the defects and the bottom of metal member 2, come back to the transducer where they are reconverted into electrical pulses, the latter being transmitted to the amplifier of apparatus 3, the screen 4 of which faces photocells 5, the indications provided by each of which are transmitted through an amplifier to one of the stylus shown at 7 engaging a common record sheet of paper 8 of a special type to be described hereinafter. A group of amplifiers, each connected to a respective photocell and stylus, is mounted in box 6.

Transducer 1 moves in the direction of the arrow F and is adapted also to be shifted laterally so as to travel in succession over a plurality of parallel paths and the record paper is actuated by a synchro system comprising receiving selsyn rotor 39a and transmitting selsyn rotor 391) rotating at the same speeds. Rotor 39b is actuated by small wheel 39c whose axle is mounted on handle 40 of transducer 1. The paper unwinds in the direction of the arrow F so that the quartz 9 in the transducer may detect in succession the defects 10111213 of the member 2, which defects are recorded on the un winding paper as corresponding lines or dashes '14, l5, 16, 17 while the starting pip is recorded at 18 and the echo from the bottom of the member 2 at 19.

Fig. 2 is an electric wiring diagram for such an arrangement, which includes chiefly means for amplifying the modulations as illustrated by the parts inside the rectangle 20 drawn in broken lines. These amplifying means form part of the supersonic detecting apparatus 3, the cathode ray oscillograph 21 which is provided with the photocells 5, preferably of the barrier layer type, the said photocells being electrically connected with the amplifying means 6 which serve for the recording signals, and which are shown inside a further rectangle drawn in broken lines. The said amplifying means control the recording means 7--8 in which the special paper sheet unwinds, the amplifying means also controlling the acoustic indicator or loud speaker 22.

The amplifying means for the modulation produced by the quartz, as illustrated by the parts drawn inside the rectangle 20 operate in a manner which will be readily understood. The amplified voltage transmitted by the vibration-receiving quartz 9 contained inside transducer 1, is not fed directly to the vertical deflecting plates of the oscillograph but to the grid of a first amplifying tube 23 through the agency of a two-way switch 24. A potentiometer 25 allows adjusting a grid leak so as to modify the voltage controlling the tube 23 and consequently the sensitivity of the amplifier. A second tube 26 provides for returning the amplified voltage into phase with the control voltage and this amplified voltage is then fed to control grid 27 of the cathode ray tube 21.

The amplified voltage applied to the control grid allows those electrons to pass which would otherwise be stopped by the direct current negative voltage applied to the grid.

Each photo-cell 5 after having been impressed by that portion of the diagram projected on the screen 4 which is in register with the said cell on the cathode ray oscillograph produces a current the voltage of which is amplified by two triodes 28a-28b and by a power pentode 29. The anode circuit of the said pentode feeds the primaries, inserted in parallel, of two transformers 3t) and 31. The secondary of the transformer 30 produces the voltage to be applied between the stylus 7 and the special paper sheet 8. A switch 32 allows connecting the anode of the pentode 29 with the transformer 31 the secondary of which energizes the loud speaker 22.

Transducer 1 is illustrated with further detail in Figs. 3 and 4. It includes the quartz 9 connected with the lead 33 and secured to a rod 34 rigid with a stationary spindle 35 arranged coaxially of the transducer. The piezo-electric quartz is contained inside a liquid-filled chamber constituted by two parallel discs 36 the outer edges of which are interconnected by a substantially torus-shaped case 37 made of rubber or the like yielding material. The said case is held through its edges between the outer edges of the discs 36 and cooperating covers 38 for the latter. A small frame with two rollers 39 (Fig. 1) holds the transducer in a vertical plane in contact with the member 2 to be examined, while two handles 40 on the carrier frame provided for the said rollers 39 allow shifting it over the said member. By reason of the weight of the arrangement, the torus-shaped case, which assumes the shape of a vehicle tire, engages the member to be examined through a large contacting area, which provides very favorable conditions for the propagation of the supersonic waves.

The oscillogram produced by the said waves through the electronic arrangement described hereinabove, on the screen of the cathode ray tube, impresses, as shown in Figs. 5 and '6, a row of small photo-cells 5 of the barrier layer type, the said cells being carried in contacting relationship with the screen 4 of the detecting means 3. The different cells 5 are mounted in corresponding housings 41 provided in a support 42 made of transparent synthetic material such as that known under the registered trade name Plexiglas. This support, shaped so as to match the convex shape of the screen, is secured to a plate of the like synthetic material 43 which serves as a carrier for the whole system; the said plate 43 is adapted to be secured to the safe edge 44 surrounding the supersonic detecting means 3, through the agency of a clip 45. A conductive wire 46 illustrated in Fig. 6 as lying to the front of the support 42 (Figs. 2 and-6) is in contact with the collecting point 47 of each photocell 5 while the said wire is, on the other hand, held by the transparent synthetic material forming the support between the successive cells and it is urged against the collecting point of each cell by an insulated wire 48. To the rear of the support 42, set screws 49 exert a pressure on the corresponding cells, while providing simultaneously an electric contact. These set screws allow adjusting the pressure on both sides of each cell so as to obtain an excellent electrical contact without any damage to the said cell; this adjustment should be performed separately for each photocell.

Finally, a conductive wire 50 welded to each set screw 49 leads the voltage collected by the cell to an eye terminal 51 acting as a relay and forming the starting point for an armoured wire 52 leading to the amplifier 6.

At the output end of the amplifier 6, as shown in Fig. 2, the amplified current produced by each cell passes, as mentioned hereinabove, into the primaries of the two transformers 30 and 31. The secondary of the transformer 30 produces the voltage feeding the stylus 7 of which there is one for each cell, each stylus rubbing on a common colored sheet 8 the composition of which is as follows: the said sheet is made for instance of paper of a commercial grade obtained through incorporation of carbon to the paper pulp so that the said paper hecomes electrically conductive. On its upper surfaces is laid a thin coat of insulating material, preferably of a whitish color. When a difference in potential arises between the conductive surface of the paper and the stylus rubbing over the insulated surface thereof, a spark jumps and perforates the layer of insulating material so that the black material of the paper appears to view. It is thus obvious that each time a luminous spot registers with a photocell so that the amplifier sets up a difference in voltage between the paper and the corresponding stylus, the insulating layer is perforated in register with the said stylus.

Fig. 2 shows that the loud speaker 22 and the recording means may be actuated simultaneously and it is possible, with the incorporation of a further switch, to make the loud speaker 22 become operative in lieu of the actual recording means.

On the other hand, instead of resorting to a row of photocells, it is possible to use e. g. a single cell adapted to be moved by hand in a direction parallel with the screen surface so as to occupy the location corresponding to the section of the member to be examined and containing possibly a defect.

By way of example and to show the manner of operating the above described supersonic investigating means, Fig. 7 is a diagrammatic illustration of the steps of the procedure of examination of an elongated flat member 53. In the said Fig. 7, 54 designates the conventional oscillogram and 55 the modulated oscillogram obtained through the above described arrangement. The photocells and the amplifier provided for recording have been illustrated diagrammatically at 5 and at 6 respectively. The starting pip producing luminous spots 56 and 57 on the oscillograph screens produces two dashes 58 on the special recording paper. Similarly, the echo from the bottom of the member to be examined corresponds respectively to spots 59 and 60 and to dashes 61. Lastly, the defects 62 which are not in the same horizontal plane in the member 53 appear respectively at 63 and at 64 on the screens and at 65, in the shape of dashes, on the special record paper unwinding in the direction of the arrow F while the transducer is shifted in the direction of the arrow F Only two defects are shown on the oscillograph screen at 63 and 64 because only two defects are met by the ultra-sonic beam at the instant considered. Dashes 65 correspond to these defects and to other defects which have been met previously by the ultra-sonic beam.

Obviously, it is possible without unduly widening the scope of our invention, to modify or improve, within the scope of the accompanying claim, various parts of the arrangement disclosed.

What we claim is:

A supersonic arrangement for detecting and indicating defects in a metal object, comprising means for generating electrical pulses, testing means including an electroacoustic transducer adapted to be moved over the object, means for applying the generated pulses to the transducer, said pulses being converted in the transducer into mechanical vibrations, supersonic waves produced by said vibrations being reflected from the object and being reconverted in the transducer to electrical pulses, means controlled by said transducer and including a cathode ray oscillograph with a screen, a diagram being formed on the screen under the action of said pulses, said diagram including highly illuminated dots formed by any pulse reflected from a defect in the object, at least one photo-cell engaging the surface of the screen, said cell being adapted to be illuminated by a screen portion registering therewith and to produce current when said screen portion carries one of said highly illuminated dots, an amplifier, a transformer having a primary and a secondary winding for each cell, each cell being electrically connected to said amplifier and the amplifier being connected to said transformer primary, a sheet of conductive material, an insulating layer covering said sheet, a plate in supporting contact with said sheet and connected to one lead of said secondary, means for unwinding the sheet, and a stylus for each cell in contact with said insulating layer and connected to the other lead of the secondary, whereby a spark due to current flowing out of the secondary of the transformer corresponding to the respective stylus and cell breaks through the insulating layer to make the underlying conductive sheet visible and thus to form a record of the current passing out of the photo-cell.

References Cited in the file of this patent UNITED STATES PATENTS 2,031,951 Hartley Feb. 25, 1936 2,501,791 Silverman Mar. 28, 1950 2,534,369 Ress Dec. 19, 1950 2,560,606 Shive July 17, 1951 2,545,101 Meunier Mar. 13, 1951 2,603,966 Drake July 22, 1952 2,693,105 Staehl et a1. Nov. 2, 1954 2,699,061 Drake Jan. 11, 1955 FOREIGN PATENTS 1,078,409 France May 12, 1954 1,081,609 France June 9, 1954 UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 2,836,059 I May 27, 1958 Louis Beaujard et al0 It is hereby certified that error appears" in the above numbered patent requiring correction and that the said Letters Patent should read as cor= rected below.

In the heading to the printed specification, line 10, for Claims priority, application Germany October 28, 1953" read Claims priority, application France October 28, 1953 o Signed and sealed this 8th day of July 19580 (SEAL) Attest:

KARL H. AXLINE ROBERT C. WATSON Attesting Officer Commissioner of Patents UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No, 2,836,059 v May 27, 1958 Louis Beaujard et a1,

It is hereby certified that error appears in the above numbered patent requiring correction and that the said Letters Patent should read as cor-= rected below.

In the heading to the printed specification, line 10, for "Claims priority, application Germany October 28, 1953 read Claims priority, application France October 28, 1953 a Signed and sealed this 8th day of July 1958,

(SEAL) Attest:

KARL H. AXLINE ROBERT C. WATSON Attesting Officer Commissioner of Patents

Images