Title of Invention

A METHOD AND DEVICE FOR DETERMINING THE POSITION OF AN ELONGATED, RELATIVELY NARROW OBJECT RELATIVE THE SURFACE OF AN OBSTRUCTING

Abstract

The invention refers to a method for determining the position of an elongated narrow object relative the surface of an obstructing disk-like body in front of said object and oriented at an angle thereto, by means of electromagnetic ionizing radiation, for guidance of the movement of an associated laser welding equipment. For providing the carrying out of this method with high speed and greatest precision when manufacturing sandwich elements with conical or double-curved surface it is suggested according to the invention that from the side of the body remote from the object is directed, under approximate movement in the longitudinal direction of the object one precisely collimated radiation beam obliquely to the object under simultaneous scanning motion at right angles thereto, that the radiation back-scattered from the object is collected at the same side of the body and is brought to form a signal which is compared with memory-stored predetermined preference signals for the desired correct position of the object relative the body. The invention also suggests a device for carrying out this method.

Full Text

FORM 2 THE PATENTS ACT 1970 [39 OF 1970] & THE PATENTS RULES, 2003 COMPLETE SPECIFICATION [See Section 10; rule 13] "A METHOD AND DEVICE FOR DETERMINING THE POSITION OF AN ELON¬GATED, RELATIVELY NARROW OBJECT RELATIVE THE SURFACE Op AN OBSTRUCTING" VALVO AERO CORPORATION, 81 TroUhattan, S-461, Sweden and FORCE INSTITUTTET, Park Alle 345, DK-2605 Brondby, Denmark, The following specification particularly describes the invention and the manner in which it is to be performed: The present invention relates to a method for determining the position of an elongated, relatively narrow object relative the surface of an obstructing. The present invention refers to a method and appara¬tus for determining the position of an elongated, rela¬tively narrow object relative the surface of an obstruct¬ing, preferably disk-like body in front of said object, and oriented at an angle" thereto, by means of electromagnetic radiation, particularly ionizing radiation, for guidance of the movement of an associated treatment equipment, particu- larly for laser welding. Previously electromagnetic radiation as been used for finding hidden materials such as narcotics, explosives and other contraband etc. One example is the GB-A-2 055 198. Other examples are US-A-5 600 700 and US-A-5 648.619. In WO 95/00725 has been described the manufacture of a so-called sandwich element, i.e. a double-walled sheet metal element, particularly for use in the manufacture of ships. How this manufacture including welding of its spac¬ing . walls is to b"e carried out is not /evident, however. Still it deals in.this case with plane, sheet metal walls having standardized and preferably right-angular shape which makes the problem more simple. Another and more difficult problem occurs when sand¬ wich elements are to be made, which have conical or double- curved surface such as in rocket nozzles or the like. Then very high requirements as to precision are put when it comes to welding through the obstructing sheet wall against the narrow side or edge of the spacing means, the width of which is less than 1 mm. Therefore, the main object of the present invention is to solve this problem and this is achieved by means of a - 2 method according to the invention, which is substantially distinguished in that from the side o:: the body remote from the object is directed, under approximate movement in the longitudinal direction of the object at least one precisely collimated radiation beam obliquely to the object under si¬multaneous oscillating or scanning motion at right angles thereto, that the radiation back-scattered from the abject is collected at the same side of the body and i,3 brought to form therefrom a signal which is compared with memory- stored signals for the desired correct position of the ob¬ject relative the body, for guidance of the radiation beam motion along the object and hence also the motion of the associated equipment. For obtaining the highest possible precision in the method it is preferred, as is stated in the subsequent claim 2 that also the back-scattered radia¬tion is collimated. For carrying out this method it has been suggested at the same time a device comprising a detecting device for determination of the position of an elongated and rela tively narrov; object relative the surface of an obstructing body in front of said object and oriented at an angle thereto and preferably of disk-like shape by means of elec¬tromagnetic and preferably ionizing radiation for guidance of the movement of an associated treatment equipment, par- ticularly for laser welding. The features substantially distinguishing said device are substantially that the de¬tecting device which is arranged at the same side of the disk-like body as the sender device, is adapted to receive a radiation emitted from the sender device towards the ob- 3(0 ject and back-scattered from the object and to form there¬from a signal and in that a comparator is arranged to com¬pare said signal with predetermined preference signals stored in a memory, for the desired correct pcs:.tion of the 3 3 object relative the body for guidance of the movement of the radiation beam along the object and hence also the mo¬tion of the associated equipment. By the inventive method and device it is now made possible, in a surprisingly effective manner a rapid and effective operation with high precision in the function, such as in laser welding of double-curved and double-walled panels. In doing so the welding speed will be allowed to be as great as 1 000 mm per minute. The invention will be further described below with reference to the accompanying drawing on which Fig. 1 dia-grammatically illustrates a first e::nbodinient of a device according to the invention for carrying out the method and Fig. 2 illustrat.es examples of curves of the signals ob- tained from the detector means while Fig. 3 illustrates a cross-section through a plurality of spacing walls which are to be welded with the inventive method to a piece of sheet metal 3. As is evident from the drawing, the problem to be solved with the invention is that a firs.t.. shee metal piece of wall 1 which" carries one or more parallel upright and thin spacing walls 2 is to be joined with an overlying wall or metal sheet 3 by welding. Thereby this is to be made by letting a suitable welding equipment which is able to weld through said covering wall 3, precisely follow the longitu¬dinal extension of the spacing wal 2. This, however, causes very great difficulties since the wall 3 fully ob¬structs the viewing of the spacing wall 2 and the position thereof therefore has to be exactly determined without vis- ual help. According to the invention it is suggested as a solu¬tion to this problem, to use a detector unit 5 which houses a source 6 of electromagnetic radiation, particularly ion- 4 izing radiation. Preferably, said unit is mounted in a plane at right angles to the spacing wall 2 and at an angle of Q/2 to the wall 3. In combination with the radiation source 6 is ar- ranged a detector means 7 which is mounted at an angle to the radiation source 6, preferably in an opposite angle of Q/2 to the spacing wall 2 so that the position of inter¬ference between the radiation beam emitted from the source 6 and the observation zone of the detector means 7 will be 1) located at a distance below the wall 3. If the detector de¬vice 5 then is carried to and from in the direction of the arrow A over the spacing wall 2 in EI scanning motion the radiation emitted from the source 6 will change in a char¬acteristic manner when passing above the spacing wall 2 due 15 to changes in the back-scattering of the radiation by the presence of a predetermined volume of material therein, in this case metal. This circumstance is utilized for forming a signal from the detector means 7 which signal is carried to an 23 electronic processing unit 10 only diagrammatically illus¬trated, and to be compared therein by a comparator means, not illustrated, with predetermined preference signals, stored in a non-illustrated memory means for the desired correct position coordinates of the spacing wall 2 relative 25 the body 3. Depending on the result of this comparison, the electronic processing unit then creates a control signal which is carried to the non-illustrated treatment equipment to be controlled by said detector unit, particularly a la¬ser welding equipment connected with t.ie detector device 5. In this manner the equipment is brought to follow with pre¬cision said spacing wall 2 under the movement of the detec¬tor device 5 along the spacing wall 2 as well as an cscil-latina motion with small amplitude at eight angles thereto. ^^ The detector unit 5 can be made very sensible and to oper¬ate very exact with a precision of ± 0,1 millimeter, such that transport and welding speeds as high as up to 1 000 millimeters per minute are possible. In the above-stated description it is a prerequisite that the radiation source 6 and the detector means 7 are arranged stationary within the unit ii and that this unit 5 is brought to move in two directions x/y at right angles to each other in the plane of the body 3. To an artisan it is 1) of course fully obvious that if deesired the radiation source 6 instead might be stationary and the detector means 7- be moved in a direction parallel to the direction of ra¬diation. It is also possible, instead, to let the detector means 7 be stationary and to move the radiation source 6 15 parallel to the metal sheet 3 or, furthermore, with the source 6 stationary, utilize a detector means consisting of a row of detector elements. Finally, the radiation source 6 can be constituted by a plurality of sources which all emit mutually parallel and slightly spaced radiation beams, the 23 detector means then also consisting of a row o§ detector elements arranged adjacent each other or, finally in a ra¬diation source 6 with one single beam, utilize at least two stationary detector means 7 arranged at different angles. For determination of the spacing betweer. the body or 25 wall 3 and the edge surface of the spacing wall 2 to which the weld is to be made, the radiation source 6 together with the detector means 7 are brought to move to and from in z-direction i.e. in a direction at right singles to the plane of the wall 3. 3D In Fig. 2.1 a) is a curve of the variation of the"de¬tector signal obtained at the passage: of the detector means 7 of the spacing wall 2 when the same is at right angles to the wall 3, while b) illustrates the shape of the same sig- nal should the spacing wall 2 not be located .at right an¬gles. In Fig. 2.2, the curves c2, c2 and c3 illustrate three scanning operations, namely when at first no spacing wall 2 is present below the point of the detecting, and then when the radiation beam from the source 6 enters inco the spac¬ing wall 2 and finally when the beam lies entirely within said wall. In Fig. 3, examples of relevant measure statements of a-d according to the following are shown: 0,4 7 WE CLAIM : 1. A method for determining the position of an elongated, relatively narrow object (2) relative the surface of an obstructing, preferably disk-like body (3) in front of said object and oriented at an angle thereto, by means of electromagnetic radiation, particularly ionizing radiation, for guidance of the movement of an associated treatment equipment, particularly for laser welding, characterized in that from the side of the body (3) remote from the object (2) is directed, under movement in the longitudinal direction of the object at least one precisely collimated radiation beam obliquely to the object under si¬multaneous oscillating or scanning motion at right angels thereto, that the radiation back-scattered from the object is collected at the same side of the body and is brought to form a signal which is compared with memory-stored predetermined preference signals for the desired correct position of the object (2) relative the body (3), for guidance of the radiation beam motion along the object and hence also the motion of the associated equipment, also the said back-scattered radiation is collimated. 2. A device for carrying out the method as claimed in claim 1, wherein a detector device (5) for determination of the position of an elongated and relatively narrow object (2) relative to the surface of an obstructing and preferably disk-like body (3) in front of said object and oriented at an angle thereto, by means of electromagnetic radiation, 8 preferable an ionizing radiation, from a sender device (6) for guidance of the movement of associated treating equipment, particularly for laser welding, wherein the detector device (5) which is located at the same side of the disk-like body (3) as the sender device (6) is adapted to receive a radiation emitted from the sender device and directed towards the object (2) and back-scattered from the object and to form therefrom a signal, and that a comparator means is adapted to compare said signal with predetermined preference signals for the desired correct position of the object relative the body (3), stored in a memory means, for guidance of the motion of the radiation beam along the object (2) and hence also the movement of the associated equipment. 3. A device as claimed in claim 2, wherein collimator also for the back-scattered radiation. Dated this 10th day of August, 2000. (RITUSHKA NEGI) OF REMFRY 8B SAGAR ATTORNEY FOR THE APPLICANTS 9

Documents:

abstract1.jpg

in-pct-2000-285-mum-cancelled pages(09-06-2005).pdf

in-pct-2000-285-mum-claims(granted)-(09-06-2005).doc

in-pct-2000-285-mum-claims(granted)-(09-06-2005).pdf

in-pct-2000-285-mum-correspondence(09-06-2005).pdf

in-pct-2000-285-mum-correspondence(ipo)-(1-6-2004).pdf

in-pct-2000-285-mum-drawing(09-06-2005).pdf

in-pct-2000-285-mum-form 1(10-08-2000).pdf

in-pct-2000-285-mum-form 19(01-04-2004).pdf

in-pct-2000-285-mum-form 1a(09-06-2005).pdf

in-pct-2000-285-mum-form 2(granted)-(09-06-2005).doc

in-pct-2000-285-mum-form 2(granted)-(09-06-2005).pdf

in-pct-2000-285-mum-form 3(09-06-2005).pdf

in-pct-2000-285-mum-form 3(11-08-2000).pdf

in-pct-2000-285-mum-form 5(11-08-2000).pdf

in-pct-2000-285-mum-form-pct-isa-210(11-08-2000).pdf

in-pct-2000-285-mum-petition under rule 137(09-06-2005).pdf

in-pct-2000-285-mum-power of authority(09-06-2005).pdf

in-pct-2000-285-mum-power of authority(09-08-2000).pdf