SE463582B

SE463582B - PROCEDURES FOR LONG Saturation Of BRAEDOR AND DEVICE FOR IMPLEMENTATION OF THE PROCEDURE

Info

Publication number: SE463582B
Application number: SE8903692A
Authority: SE
Inventors: P Ottosson
Original assignee: Rema Control Ab
Priority date: 1989-11-03
Filing date: 1989-11-03
Publication date: 1990-12-10
Also published as: NO904743D0; FI905148A7; FI905148A0; NO904743L; DE4033397A1; SE8903692D0

Description

465 582 z medbringarna 11. En pulsgivare 12 eller någon annan givare avkän- ner transportörens 10 frammatningsrörelse i pilens P riktning och inmatar sina utsignaler i en elektronisk utvärderings- och beräk- ningsenhet 15. Transportörer, pulsgivare och elektroniska enheter av detta slag är kända inom sågverksindustrin. 465 582 z the carriers 11. A pulse encoder 12 or some other sensor senses the forward movement of the conveyor 10 in the direction of the arrow P and inputs its output signals into an electronic evaluation and calculation unit 15. Conveyors, pulse encoders and electronic units of this type are known in the sawmill industry.

De på tvärtransportören 10 frammatade brädorna B har (vid en jämnad första ände) en första kortsida Bl, vars position är känd, t ex av den anledning, att den glider utmed en styrskena 10c, samt (vid en icke jämnad andra ände) en andra kortsida B2.The boards B fed forward on the cross conveyor 10 have (at a leveled first end) a first short side B1, the position of which is known, e.g. for the reason that it slides along a guide rail 10c, and (at an unleveled second end) a second short side B2.

Genom att bestämma kortsidans B2 läge relativt kortsidan B1 bes- täms brädans B längd L.By determining the position of the short side B2 relative to the short side B1, the length L of board B is determined.

Intill transportörens 10 ena sidokant 10' är en laser 13 anordnad, som strax över transportytan l0b utsänder ett laser- stràlningsknippe 13a vilket divergerar i horisontell riktning och bildar en av gränsstrålar 13a' och 13a" som av skarpa grânslijer begränsad triangelformig strålningssektor, vars utsträckning i frammatningsriktningen P med fördel i stort sett svarar mot av- ståndet mellan två intill varandra liggande medbringarrader på transportören 10, t ex raderna 11' och 11".Next to one side edge 10' of the conveyor 10, a laser 13 is arranged, which just above the transport surface 10b emits a laser radiation beam 13a which diverges in the horizontal direction and forms a triangular radiation sector limited by boundary rays 13a' and 13a" as sharp boundaries, the extent of which in the feed direction P advantageously corresponds largely to the distance between two adjacent carrier rows on the conveyor 10, e.g. rows 11' and 11".

För att med säkerhet kunna mäta även brädor med kraftig flatböj, och/eller sådana, som tenderar att stå upp, får strål- ningssektorn l3a ha en viss "tjocklek", dvs en icke försumbar di- mension i riktningen lodrätt mot transportytan, och detta kan uppnås t ex därigenom, att lasern 13 förses med en optik som breddar det utsända strålningsknippet i vertikal riktning, eller genom att flera lasrar stackas över varandra.In order to be able to reliably measure even boards with a strong flat bend, and/or those that tend to stand up, the radiation sector l3a must have a certain "thickness", i.e. a non-negligible dimension in the direction perpendicular to the transport surface, and this can be achieved, for example, by providing the laser 13 with optics that broadens the emitted radiation beam in the vertical direction, or by stacking several lasers on top of each other.

Intill samma sidokant 10' är två riktade mottagare 14' och 14" anordnade, som är känsliga för den av lasern 13 utsända strålningen. I föreliggande beskrivning och i de närslutna pa- tentkraven betecknas med termen "synfält", när den används i sam- band med en mottagare, det område, varifrån strålningen kan komma för att kunna uppfånga av mottagaren. Med "riktad mottagare" me- nas sedan i föreliggande beskrivning och i närslutna patentkrav en mottagare med ett linjeformigt smalt synfält, dvs ett synfält i huvudsak i form av en enda linje eller en enda plan yta som sträcker sig lodrätt mot transportytan 10c och i planvyn också har formen av en linje. 463 582 I fig 1 kan således linjerna l4'a och 14a" represente- ra antingen strax över trﬂnsportytan förlöpande linjeformiga syn- fält, eller lodrätt mot transportytan förlöpande plana, ytformiga synfält. Skälet för användning av en mottagare med ett ytformigt 3 synfält är detsamma som för användning av en "tjock" strålnings- sektor.Next to the same side edge 10', two directional receivers 14' and 14" are arranged, which are sensitive to the radiation emitted by the laser 13. In the present description and in the appended patent claims, the term "field of view", when used in connection with a receiver, denotes the area from which the radiation can come in order to be captured by the receiver. By "directional receiver" is then meant in the present description and in the appended patent claims a receiver with a linear narrow field of view, i.e. a field of view essentially in the form of a single line or a single flat surface which extends perpendicularly to the transport surface 10c and in the plan view also has the form of a line. 463 582 In Fig. 1, the lines 14'a and 14a" can thus represent either linear fields of view extending just above the transport surface, or perpendicularly to the transport surface flat, surface-shaped fields of view. The reason for using a receiver with a surface-shaped 3 field of view is the same as for using a "thick" radiation sector.

Inskränkning av en mottagares mottagningsområde så att ett linje- eller ytformigt synfält erhålles kan t ex åstadkommas därigenom, att framför mottagaren anordnas ett bländarelement 14b, som i fallet med ett linjeformigt synfält utgörs av ett smalt rör, och i fallet med ett ytformigt synfält av två plana ytor som är separerade av ett smalt gap.Restriction of a receiver's reception area so that a linear or planar field of view is obtained can be achieved, for example, by arranging an aperture element 14b in front of the receiver, which in the case of a linear field of view consists of a narrow tube, and in the case of a planar field of view consists of two flat surfaces separated by a narrow gap.

Mottagarna 14' och 14" är anordnade på ett inbördes av- stånd A i frammatningsriktningen P och på så sätt, att deras syn- fält l4'a och 14"a konvergerar med en vinkel mot varandra och skär varandra på ett ställe V som ligger på ett avstånd C från sidokanten 10'.The receivers 14' and 14" are arranged at a mutual distance A in the feed direction P and in such a way that their fields of view 14'a and 14"a converge at an angle to each other and intersect at a location V which is at a distance C from the side edge 10'.

Den del av det mellan synfälten 14'a och 14"a inneslut- na området, vilken i hela sin utsträckning i riktningen för fram- matningsrörelsen P ligger inom strålningssektorn 13a, bildar en mätzon M. I fig 1 visas den av en linje e begränsade mätzonen M med streckad schraffering. Märke bör läggas till att det bortom linjen e belägna avsnittet n inte längre svarar mot villkoret att i frammatningsriktningen P helt ligga inom strålningssektorn 13a.The part of the area enclosed between the fields of view 14'a and 14"a, which in its entire extent in the direction of the forward movement P lies within the radiation sector 13a, forms a measurement zone M. In Fig. 1, the measurement zone M, limited by a line e, is shown with dashed hatching. It should be noted that the section n located beyond the line e no longer meets the condition of lying completely within the radiation sector 13a in the forward direction P.

Synfältet 14'a av den mottagare 14', som ligger främst i frammatningsriktningen P, förlöper i huvudsak vinkelrätt mot denna riktning, dvs i stort sett parallellt med de uppmäta brä- dornas B längdkanter B3, B4.The field of view 14'a of the receiver 14', which is located primarily in the feed direction P, runs substantially perpendicular to this direction, i.e. substantially parallel to the longitudinal edges B3, B4 of the measured boards B.

Så snart brädan B, resp dess i frammatningsriktningen P främre hörn B2' vid den andra kortsidan B2, inträder in i mätzo- nen M, uppkommer på den andra kortsidan B2 diffus reflektion av strålningen från lasern 13, varvid en del av den reflekterade strålningen utbreder sig även exakt i synfältets 14'a riktning och når således mottagaren 14', där en signal uppstår som inmatas i enheten 15. Samma sak händer med mottagaren 14" när hörnet B2', efter att ha tillryggalagt sträckan S inom mätzonen M, håller på att lämna denna mätzon.As soon as the board B, or rather its front corner B2' at the second short side B2 in the feed direction P, enters the measurement zone M, diffuse reflection of the radiation from the laser 13 occurs on the second short side B2, whereby part of the reflected radiation also propagates exactly in the direction of the field of view 14' and thus reaches the receiver 14', where a signal arises which is fed into the unit 15. The same thing happens with the receiver 14" when the corner B2', after having covered the distance S within the measurement zone M, is about to leave this measurement zone.

Det är alltså de första i mottagarna 14' och 14" utlös- 463 582 4 ta signalerna, ästadkomna i det ögonblick, då den diffusa reflek- tionen för första gängen har nått respektive mottagare, vilka re- gistreras i enheten 15 för att tillsammans med signalerna från givaren 12 tjäna till beräkningen av längden av sträckan S (vil- ken ligger pä ett avstånd E från punkten V, vars oföränderliga läge är känt).It is thus the first signals triggered in the receivers 14' and 14", produced at the moment when the diffuse reflection has first reached the respective receiver, which are registered in the unit 15 in order to serve, together with the signals from the sensor 12, for the calculation of the length of the distance S (which is at a distance E from the point V, whose unchanging position is known).

Till samma ändamål kan emellertid även de sista signa- lerna användas vilka uppkommer när mottagningen slutar efter det, att reflekterad strålning har (under en viss tid) mottagits. Det- ta händer när det bakre hörnet B2" hos den andra kortsidan B2 har passerat först synfältet 14a', och sedan synfältet 14"a.For the same purpose, however, the last signals which arise when reception ends after reflected radiation has been received (for a certain time) can also be used. This happens when the rear corner B2" of the second short side B2 has first passed the field of view 14a', and then the field of view 14"a.

Eftersom mätzonen M har, tack vare synfâltens l4'a, 14"a icke parallella (i fig l konvergerande) förlopp, varierande utsträckning i riktningen P, medger kännedomen av sträckans S storlek att med hjälp av elementära geometriska formler faststäl- la denna sträckas läge mellan sidokanterna lO', 10", och därige- nom även relativt styrskenan l0c, och således fastställa brädans B längd L.Since the measuring zone M has, thanks to the non-parallel (in Fig. 1 converging) course of the field of view l4'a, 14"a, a varying extent in the direction P, knowledge of the size of the section S allows, with the aid of elementary geometric formulas, to determine the position of this section between the side edges lO', 10", and thereby also relative to the guide rail l0c, and thus to determine the length L of the board B.

Vid arrangemanget enligt fig 1 beräknas längden L ur formeln C L = si + (D-c) och ur liknande enkla formler kan längden L härledas även i an- ordningarna enligt de följande ritningsfigurerna.In the arrangement according to Fig. 1, the length L is calculated from the formula C L = si + (D-c) and from similar simple formulas the length L can also be derived in the arrangements according to the following drawing figures.

Observeras bör att synfälten 14'a, l4"a även kan di- vergera i stället för att konvergera; det allmäna villkoret är, att de icke får vara parallella.It should be noted that the fields of view 14'a, 14"a can also diverge instead of converging; the general condition is that they must not be parallel.

I fig 2 visas ett alternativ där lasern 13 har ersatts av en làngsträckt ljuskälla 23 (t ex lysrör) som sträcker sig ut- med hela sträckan A mellan mottagarna 14' och 14" och skapar en mätzon M' i vilken inryms även brädor med större längd.Fig. 2 shows an alternative where the laser 13 has been replaced by a long-range light source 23 (e.g. fluorescent tube) which extends the entire distance A between the receivers 14' and 14" and creates a measurement zone M' in which boards of greater length are also accommodated.

Mottagaren l4', vars synfält l4'a i utföringsformen en- ligt fig l eller 2 förlöper väsentligen parallellt med brädornas B längskanter B3, B4, kan enligt fig 2 ersättas av en billigare anordning, nämligen ett fotocellpar bestående en fotocellsändare l6s och en fotocellmottagare 16m, vilka, eventuellt försedda med en vertikal spalt, är anordnade utmed en linje 16 som represente- rar ljusbanan de emellan och som förlöper i huvudsak parallellt med brädornas B (fig l) längskanter B3, B4. s 463 582 Eventuellt kan två sådana fotocellpar stackas ovanpå varandra för att klara brädor med uppåtriktad flatböj, och de två paren skall då avläsas oberoende av varandra ("el1eru-funktion i stället för "och"-funktion).The receiver 14', whose field of view 14'a in the embodiment according to Fig. 1 or 2 runs essentially parallel to the longitudinal edges B3, B4 of the boards B, can be replaced according to Fig. 2 by a cheaper device, namely a photocell pair consisting of a photocell transmitter 16s and a photocell receiver 16m, which, optionally provided with a vertical gap, are arranged along a line 16 which represents the light path between them and which runs essentially parallel to the longitudinal edges B3, B4 of the boards B (Fig. 1). p 463 582 Optionally, two such photocell pairs can be stacked on top of each other to handle boards with an upward flat bend, and the two pairs should then be read independently of each other ("or" function instead of "and" function).

En begynnelsesignal alstras när ljusbanan 16 skyms resp avbryts av det framskjutande hörnet B2' (fig 1).An initial signal is generated when the light path 16 is obscured or interrupted by the protruding corner B2' (Fig. 1).

När den första mottagaren 14' (fig 1) har ersatts med ett fotocellpar, kan vidare lasern 13 och den i frammatningsrikt- ningen på andra plats anordnade mottagaren 14" (fig 1) byta plats och funktion med varandra. Lasern 130 (fig 3) anordnas då att alstra ett linjeformigt smalt strálningsknippe 130a (dvs i form av en linje eller en vertikal plan yta), och placeras på mottag- arens 14" plats med strâlningsknippet 130a förlöpande i samma riktning som mottagarens 14" synfält 14"a, dvs icke parallellt med ljusbanan 16.When the first receiver 14' (Fig. 1) has been replaced by a pair of photocells, the laser 13 and the receiver 14" (Fig. 1) arranged in the second place in the feed direction can also exchange places and functions with each other. The laser 130 (Fig. 3) is then arranged to generate a linear narrow beam of radiation 130a (i.e. in the form of a line or a vertical flat surface), and is placed in the place of the receiver 14" with the beam of radiation 130a extending in the same direction as the field of view 14"a of the receiver 14", i.e. not parallel to the light path 16.

Mottagaren 14 placeras på laserns 13 plats och anordnas att ha ett synfält 14a i form av en bred "känslighetslob" 14a.The receiver 14 is placed in the location of the laser 13 and is arranged to have a field of view 14a in the form of a wide "sensitivity lobe" 14a.

Mätzonen M" sträcker sig i detta fall redan från linjen 16.The measuring zone M" in this case already extends from line 16.

Enligt fig 4 kan var och en av mottagarna 14', 14" er- sättas med ett (eller flera ovanpå varandra stackade) fotocellpar 16s-16m, 16s'-16m', så att lasern helt utgår. Anordningen består då av tvâ (eller fyra etc ovanpå varandra stackade) fotocellpar vilkas ljusbanor 16, 16' korsar varandra.According to Fig. 4, each of the receivers 14', 14" can be replaced by one (or several stacked on top of each other) photocell pairs 16s-16m, 16s'-16m', so that the laser is completely extinguished. The device then consists of two (or four, etc. stacked on top of each other) photocell pairs whose light paths 16, 16' cross each other.

Eftersom hos utföringsformen enligt fig 4 kan medbring- arna ll eventuellt ha störande verkan på den snett mot frammat- ningsriktningen P förlöpande ljusbanan 16', kan för eliminering av denna olägenhet enligt fig 5 anordnas två eller ännu flera ljusbanor 16', 16" genom att tvâ eller flera fotocellpar 16s'/- /16m', 16s"/l6m" (vilka givetvis vart och ett kan uppvisa på var- andra stackade element) anordnas intill varandra så, att deras ljusbanor innesluter icke identiska vinklar ß, ß' med frammat- ningsriktningen P.Since in the embodiment according to Fig. 4 the carriers 11 may possibly have a disturbing effect on the light path 16' running obliquely to the feed direction P, in order to eliminate this disadvantage according to Fig. 5 two or more light paths 16', 16" can be arranged by arranging two or more photocell pairs 16s'/- /16m', 16s"/16m" (which of course can each have stacked elements) next to each other so that their light paths enclose non-identical angles ß, ß' with the feed direction P.

Brädans B framskjutna hörn B2' skär då alltid åtmin- stone en sådan "sned" ljusbana, oberoende av brädans längd och bredd. Om hörnet B2' faller i det i fig 5 skuggade området, er- hålles god konditionering.The protruding corner B2' of board B then always intersects at least one such "oblique" light path, regardless of the length and width of the board. If corner B2' falls in the shaded area in Fig. 5, good conditioning is obtained.

Claims

463 582 s Patent Claims

A method for measuring the length of boards which on a cross conveyor, the transport surface of which is laterally bounded by two side edges, are transported in the feed direction of the conveyor through a measuring zone extending at least part of the width of the transport surface, the position of the first short side of the boards for the second short side is determined by means of a radiation which is detected after reflection on this short side, characterized in that the measuring zone is limited by a first boundary in the feed direction, and a boundary line in the second feed direction, which are not parallel to each other and run between both the side edges, so that the extent of the measuring zone in the feed direction varies depending on the position between the side edges, and that the other short side of the boards is passed through the measuring zone and the length of the distance traveled by one of the corners on the other short side within the measuring zone is determined. by registering the passage of said corner on an optoelectric route both boundary lines, and on the basis of this value and the known geometry of the measuring zone, the position of the corner is calculated relative to one of the side edges, and the length of the board is determined by comparing this position with the known position of the first short side.

Method according to claim 1, characterized in that one of the boundary lines extends perpendicular to the feed direction.

Method according to Claim 1 or 2, characterized in that the boundary lines consist of linearly narrow, mutually converging fields of view of two directional receivers which are spaced apart in the direction of feed along one of the side edges, and that a light source is illuminated. at least a part of the area enclosed between these fields of view, which illuminated part forms the measuring zone, said recording being effected by recording in one receiver radiation which is diffusely reflected by said corner when it enters the measuring zone, and is recorded by the other receiver radiation which is diffusely reflected by said corner when it exits the measuring zone.

Method according to claim 1 or 2, characterized in that at least one of the boundary lines consists of the light path between a photocell transmitter and a photocell receiver which forms a cooperating photocell pair, and that said registration is effected by the beginning and / or the end of the interruption of this light path, when said corner passes by, is recorded.

Method according to claim 2 and claim 4, when both boundary lines are formed by said light paths, characterized in that the exit from the measuring zone is registered by interruption of at least one further light path extending at an deviating angle obliquely towards the feed direction.

Method according to claim 3, characterized in that the length L of the board is calculated according to the formula CL = S.-Ã ~ '+ (D "C), where S is the length of the distance that a corner has traveled within the measurement zone, C is the distance of the intersection of the two converging boundary lines from the receivers, measured perpendicular to the feed direction, A is the mutual distance of the receivers, and D is the distance between the receivers and the first end of the board, measured perpendicular to the feed direction.

Device for carrying out the method according to one or more of the preceding claims, comprising a transverse conveyor (10) with a conveying surface (10a ') limited by two side edges (10', 10 "), light transmitter and receiver means (13, 16s , l6s', loose ", 130: l4 ', 14", l6m, 16m', l6m ") arranged next to at least one of said side edges so that a measuring zone (M) is provided close over the transport surface, and a means ( 12) for sensing the movement of the conveyor, and an electronic device (15) for receiving signals from the receiving means and from the sensing means, characterized in that the transmitting and receiving means are arranged so that the measuring zone is limited by two sharp boundary lines ( 14a ', 16; 13a ", 16') which are not parallel to each other, so that the measuring zone has an extent in the feed direction (P) of the cross conveyor which varies depending on the position between the side edges.

Device according to claim 7, characterized in that the light emitting means is a laser (13) which emits a diverging beam of radiation (13a), and that the light receiving means are two spaced apart (A) in the transport direction (P) receiver (14 ', 14 ") with converging, linearly narrow field of view (14'a, 14" a).

Device according to claim 7, characterized in that the light transmitter means is a linear light source (23), that the light receiver means are two spaced apart receivers (14 ', 14 ") arranged with each other in the direction of transport. converging, linear narrow field of view (14'a, 14 'a), and that the light source extends between the receivers.

Device according to claim 7, characterized in that said means comprise at least one pair of photocell transmitters / photocell receivers (16s, 16m) cooperating along a straight light path (16).

Device according to claim 10, characterized in that it comprises a laser (130) which emits a linear narrow beam of radiation (130a), and a receiver (14) which has a divergent field of view (14a).

Device according to claim 10 or 11, characterized in that at least some of the light transmitter and / or light receiver means consist of at least two units stacked on top of each other.

Device according to one or more of Claims 8 to 12, characterized in that the first boundary line (14'a, 16) extends substantially perpendicular to the feed direction of the transverse conveyor.

Device according to claims 10 and 13, characterized in that it comprises at least two pairs of photocell transmitters / receiver pairs (16s', 16s ", 16m ', 16m") arranged next to each other, the light paths (16', 16) extending obliquely towards the feed direction of the transverse conveyor. ") are not parallel to each other. * I