US 3918586 A
Apparatus for separating pieces of sheet-like material having different marginal dimensions from each other. The pieces travel over means for sensing the lengths and or widths thereof, and the pieces having certain lengths and/or widths are directed to a suction conveyor which conveys them over an opening in the apparatus, while pieces having less than said lengths and/or widths are allowed to drop through said opening.
Description (OCR text may contain errors)
I United States Patent 11 1 1111 3,918,586
Tyler et al. Nov. 11, 1975 SEPARATING APPARATUS FOR FLAT 3,395,915 8/1968 Clausen et a1. 271/197 PIECES OF DIFFERENT DIMENSIONS 3.476.241 11/1969 Ungerer 209/74 R X 3,621,266 11/1971 Akuta 250/560 1 lnvemorsi Regmald Tyler, New 3.727.911 4/1973 Vits 271/195 Westminster; Paul M. Carter, Vancouver, both of Canada n N K 1 Prinmry E.1'anzinerA en now es  Assrgnee: Durand Machine Comp y Attorney, Agent, or Firm-Fetherstonhaugh & Co.
New Westmmster, Canada  Filed: Dec. 27, 1973  Appl. No; 428,866  ABSTRACT Apparatus for separating pieces of sheet-like material  209/74 R3 209/1 11-7; 271/197 having different marginal dimensions from each other.  Int. Cl.- 8651'! 7/16 The pieces travel over means for Sensing the lengths  Fleld 0f Search 209/73, 74, 111.7; and or widths thereof and the pieces having Certain 271/1971 1941 1081250660; lengths and/or widths are directed to a suction con- 356/157 158 veyor which conveys them over an opening in the apparatus, while pieces having less than said lengths and-  References Clted /or widths are allowed to drop through saidopening.
UNlTED STATES PATENTS 3.272.351 9/1966 Burton et a1 271/197 X 8 Claims, 7 Drawing Figures Sheet 1 of4 3,918,586
US. Patent Nov. 11, 1975 US. Patent Nov. 11,1975 Sheet2of4 3,918,586
Nov. 11, 1975 Sheet 3 Of4 3,918,586
US. Patent US. Patent Nov. 11, 1975 Sheet4 0f4 3,918,586
SEPARATING APPARATUS FOR FLAT PIECES OF DIFFERENT DIMENSIONS This invention relates to apparatus for separating desired pieces of sheet-like material, such as plywood veneers, in accordance with marginal dimensions. The apparatus can be used for separating undesired pieces, such as veneer trimmings from the veneers, and/or for separating the veneers according to widths thereof.-
Although this apparatus may be used for separating many different forms of sheet-like material, it is primarily designed for separating usable plywood veneers from scraps trimmed therefrom, and for separating veneers of different widths, and for the sake of convenience, the apparatus will be described for these purposes.
According to standard practice, plywood veneer is cut from the logs in a veneer lathe. This results in the formation of plywood veneers of usable sizes, and others that are not usable. The latter pieces are usually too short and/or too narrow. The veneers travel from the lathe with the length or long dimensions thereof extending across the direction of travel and so for the sake of convenience the term length as used herein is the dimension of the veneer across the direction of travel, and the term width" is the dimension of the veneer in the direction of travel. However, the terms are relative, and therefore this invention is not to be limited by these terms, but the terms could be interchanged.
As the veneer is moved by conveyor away from the lathe, it passes through a clipper where defects, such as knot holes, splits and the like are cut out. The clipper can be operated manually or automatically. The dimensions of veneers that are considered usuable differ from mill to mill and with the different wood species being handled. For example, in some plywood plants, pieces that are at least 48 inches long and have a minimum clear width of at least 4 inches are considered to be usuable. The difficulty has been to separate the usable pieces from the scrap material. Furthermore, it is often desirable to separate or classify the usable veneers in accordance with the widths thereof. Up to the present time, these two steps have usually been done by hand, and this necessitates the use of men who are skilled enough to make a fair judgement between the usuable and unusable veneers and between the different widths of usable veneers, and who are fast enough to get the usable material off the conveyor. This results in some good veneer being erroneously left on with undersized pieces to go the scrap conveyor for chipping and/or a poor separation of the usable veneers. In addition, there are times when the men cannot handle all the veneer passing by. To offset this, the conveyors have been slowed down to enable the men to do a reasonable job.
Apparatus according to the present invention eliminates or greatly reduces this problem. As the veneer pieces move away from the clipper on the conveyor, they pass over sensing means which detect the lengths and widths thereof. For the sake of convenience, this is called an infeed conveyor, and i the end thereof is spaced from an outfeed conveyor so that there is a gap or space therebetween. A suitable transport conveyor, such as a suction conveyor, is located above the infeed and outfeed conveyors and spans the gap therebetween. In this example of the invention, when the sensor detects an acceptable or desired veneer'piece, it actuates suitable means which enables the suction conveyor to take hold of the acceptable piece and transport it to the outfeed conveyor, upon which the piece is deposited. On the other hand, if the sensing means dete cts an undesired veneer piece under the minimal marginal dimensions, that piece is allowed to reach the end of the infeed conveyor, from which it drops through the gap out of the apparatus. The preferred way is to transport the acceptable pieces to the outfeed conveyor, but it is to be understood that this may be reversed, that is, the scrap may be transported to the outfeed coonveyor and the acceptable pieces allowed to drop through the gap. In the latter case, there would be receiving means at the gap for conveying the veneers away from the apparatus. If desired, there can be a second similar stage where veneers beyond a certain width are conveyed across a gap between two conveyors, while veneers of lesser widths are allowed to drop through this gap.
Although sensing means has been described and illustrated herein for the present apparatus, it is to be understood that sensor signals from other sources can be used, such as for example, the sensor signals which cause the standard veneer clipper to operate.
This apparatus eliminates the necessity of using men to remove the scrap material from the conveyor or to separate the good veneers of different widths. Not only does this reduce the labour involved, but it is more accurate than a man can be, and the conveyors can move at a much faster speed than heretofore possible, such as a speed of about 300 feet per minute.
The selection of veneers to be transported across the gap between the infeed and outfeed conveyors is accomplished by primary suction means, and when this suction means is in operation desired veneers are selected, and when the suction is cut off, veneers are not selected. In order to enable this sorting to be accomplished so as to enable the veneers to be fed to the apparatus at high speed, the suction means can be such that the non-selected veneers are almost instantly repelled or rejected when the suction is cut off.
Apparatus according to this invention comprises an infeed conveyor, an outfeed conveyor having an end adjacent but spaced from an end of the infeed conveyor to leave a space therebetween, a transport conveyor above and extending between the adjacent conveyor ends and having front and rear ends respectively above the infeed and outfeed conveyor ends, means for applying primary suction to the front end of the transport conveyor to attract pieces from the infeed conveyor to the transport conveyor, means for applying secondary suction to the transport conveyor from near the front end thereof to near said rear end, and means responsive to dimension sensing means for selectively shutting off and applying said primary suction to attract or not to attract pieces to the transport conveyor in accordance with the dimensions of the pieces, said secondary suction retaining attracted pieces on the transport conveyor while the latter transports said pieces to the outfeed conveyor, and non-attracted pieces dropping into said gap.
Examples of this invention are illustrated in the accompanying drawings, in which FIG. 1 is a side elevation of the separating apparatus,
FIG. 2 is a plan view of the apparatus,
FIG. 3 is a cross section taken on the line 33 of FIG. 2,
FIG. 4 is a horizontal section taken on the line 44 of FIG. 1,
FIG. 5 is a diagrammatic section illustrating one form of sensor means as it will be seen on the section line 55 of FIG. 1, 7
FIG. 6 is a sectional view taken on the line .6-6 of FIG. 2, and
FIG. 7 is a diagrammatic side elevation of an alternative form of the apparatus. I
Referring to FIGS. 1 to 6 of the drawings, 10 is a preferred form of separating apparatus in accordance with this invention. This apparatus is made up mainly of an infeed conveyor 14 having an end 15 spaced from an end 16 of an outfeed conveyor 18, the spacing of the conveyor ends leaving a gap or space 20 therebetween. This gap is spanned by a transport suction conveyor which overlaps the conveyor ends 15 and 16 and is spaced above these ends. When this apparatus is used for separating plywood veneer pieces, conveyors 14 and 18 are usually wide enough to carry veneers that are more than 8 feet long in the direction across the conveyor. Although suction conveyor 25 may be the same width, it has been found convenient to place two identical suction conveyors 25 side by side, as clearly shown in FIG. 2, in order to attain the desired width. These suction conveyors are coupled together so that they in fact constitute one conveyor, and as these are identical, only one will be described in detail herein..
The infeed and outfeed conveyors may be of any standard design, and in this example, infeed conveyor 14 is made up of a plurality of laterally spaced endless belts extending around pulleys 31 at opposite ends of the conveyor, one only of these pulleys being shown in the drawings. Outfeed conveyor 18 is similar to conveyor 14 and is made up of a plurality of laterally spaced endless belts 34 extending around pulleys 35 at opposite ends of the conveyor, one only -of these pulleys being shown in FIG. 1. These conveyor belts are driven in unison in the usual manner, and the driving means therefore have been omitted.
The suction conveyor 25 includes a plurality of laterally spaced narrow belts extending around pulleys 42 and 43 mounted respectively on shaft 44 and 45 at opposite ends of the conveyor, these shafts being journalled in suitable bearings carried by the frame 47 of the conveyor. Shaft 45 has a drive pulley 49 on one end thereof which is operatively connected to a suitable source of power, such as an electric motor 50, see FIGS. 1 and 2. The shafts 45 of the two conveyors 25 are interconnected by a coupling 51, as shown in FIG. 2.
By referring to FIG. 1, it will be seen that pulleys 43 are located over outfeed conveyor 18 and spaced from the pulleys 35 thereof, while pulleys 42 lie over infeed conveyor 14 and are spaced from the pulleys 31 thereof. The belts 40 are trained over pulleys 53 mounted on shafts 54 carried by frame 47 and located immediately above infeed pulleys 31. With this arrangement, the belts 40 have lower runs 55 which are inclined upwardly in a rearward direction and are spaced a little above the upper runs of conveyor belts 30 and 34 and overlap the latter belts.
It will be seen from FIGS. 2, 3 and 5 that conveyor belts 40 are arranged in pairs. A suction box is carried by frame 47 and positioned between the upper and lower runs of two pairs of these belts which form a conveyor 25. A slot 62 is formed in the bottom of box 60 above the space between each pair of belts 40, and a pair of tubular members 65 and 66 extend along the outer surface of the box bottom at each pair of belts.
These tubular members are spaced from each other to leave a slot 67 therebetween, said slot registering with the adjacent slot in bottom 63. The lower runs 55 of each pair of the belts 40 travel along the lower surfaces of members 65 and 66, and if desired wear strips 68 and 69 may be interposed between said surfaces and the belts. Registering slots 62 and 67 bring the interior of suction box 60 into communication with the space between the adjacent pair of belts 40. By referring to FIG. 1, it will be seen that the bottom of suction box 60 extends from a front end 72 of conveyor 25, which is above gap 20 and near but clear of infeed conveyor end 15, to a rear end 73 of said conveyor, which is located over outfeed conveyor 18 and spaced from its end 16. Suction box 60 is connected by a pipe 74 to a suitable source of suction, such as a suction fan 75.
Sensing means 76 is provided at infeed conveyor 14 to sense the length and width of the veneer pieces which are moved by this conveyor towards gap 20, see FIG. 1. Standard sensor equipment can be used for this purpose. In this example, the sensing means comprises four banks 78, 79, 80 and 81 of photocells, said cells being located on half inch centers, and these banks are located just below the level of the upper runs of the belts 30 of infeed conveyors 14 near but spaced away from the end 15 of said conveyor. Light sources 84, 85, 86, and 87 are positioned respectively above banks 78, 79, 80 and 81, see FIG. 5. These sensors are operatively connected to a suction controller for attracting or not attracting veneer pieces to the front end of conveyors 25. As this sensing and actuating equipment is well known in the art, they do not require description herein. For example, this controller may be solenoid means for operating a control damper in a suction duct.
The light sources 84 to 87 constantly energize the photo-cells of banks 78 to 81. The last cells 88 of the banks are wired as act cells. That is, the instant they are covered by a veneer piece and thereby de-energized, the other cells are scanned, and if also covered by a set width of material, for example, 6 inches, the control emits an output signal. If any two of the banks are covered, indicating that the veneer piece over the cells is at least 50 inches long, a signal is sent to the controller to do the desired job. The banks 78 to 81 may be any length and may be spaced apart any desired distances, and in fact, there could be one bank extending laterally completely across the infeed conveyor.
Apparatus 10 includes means responsive to the sensing means for attracting selected veneer pieces to transporting or suction conveyor 25. The attraction is done by suction means so that when suction is applied the veneers are attracted to the conveyors 25, and when the suction is cut off the veneers drop through gap 20. If desired, the suction can be cut off in such a way as to repel veneers from conveyors 25 at the instant of cutoff.
The suction of this suction means is applied only when it is needed, and is termed herein the primary suction, whereas the suction applied by box 60 is continuous while the apparatus is in operation, and is called the secondary suction.
In this example, control suction means 96 is provided for apparatus 10 and is located immediately above the end 15 of infeed conveyor 14. This suction means includes an elongated chamber 98 extending transversely of the apparatus below the upper runs of belt 25 but spacedabove end 15 of the infeed conveyor, see FIGS. 1, 2 and This chamber is connected at one end to the inlet duct 99 of a suction fan 100'which has an outlet or discharge duct 101. Fan 100 is driven by a motor, not shown. A plurality of spaced inlet tubes 105 extend downwardly from chamber 98, there being one of these tubes for each pair of belts 40. By referring to FIG. 3, it will be seen that each tube 105 opens into chamber 98 at its upper end, and'has an open lower'end 106 which is covered by the tubular members 65 and 66 of the adjacent pair of belts 40. The interior of tube 105 communicates with slot 67 between these tubular members. In other words, there is a suction tube 105 at the lower runs of each pair of belts 40 immediately ahead of suction chamber 60.
The suction of fan 100 is selectively cut off from suction chamber 98 by suitable damper or'valve means. In this example, a damper 110 is mounted in outlet duct 101 of the fan, and is operable to open and close said duct. The damper may be operated in any suitable manner, such as by means of asolenoid 111. As an alternative to this, a damper 115 may be provided in inlet duct 99 of the fan, said damper being operated by a solenoid 116. 1
As stated above, it is preferable to provide damper 110 in outlet duct 101. This damper is normally open so that fan '100 applies suction to chamber 98 and, consequently, to tubes 105 at the pairs of belts 40. When damper 110 is closed, fan 100 no longer can draw air from chamber 98, and as this damper is on the outlet side of the fan, there is an instant and momentary back pressure through chamber 98, ducts 105 and slots 67.
On theother hand, if damper 115 is used instead of damper 110, when damper 115 is closed, the suction of fan 100 is cut off from chamber 98 and tubes 105. In this example, there is no appreciable back pressure when the damper is closed.
With this arrangement, when a piece of veneer having more than the minimum length and width is sensed by the sensor 76, damper 1 10 or damper 115 is opened to apply suction through slot 67 to the spaces between the pairs of belts 40. This suction draws the leading edge of the veneer upwardly against the lower runs of conveyor belts 40, and as these belts are moving across the bottom of suction chamber 60, the secondary suction in this chamber applied to slots 67 retains the piece against the belts until it clears the rearward end 73 of the chamber, at which time the piece drops on to outfeed conveyor 18. Thus, the selected piece is attracted to conveyor 25 and conveyed thereby across gap 20 and deposited on the outfeed conveyor. If the veneer piece moved by infeed conveyor 14 does not have the minimal length and width, the sensor sends a signal that closes damper 110 or 115 to cut off the suction from the spaces between the pairs of belts 40. This releases the veneer which has been attracted to the conveyor belts to allow it to drop through gap 20. If damper 110 is used, as is preferred, an instant and momentary back pressure is created when the damper is closed, and this repels or rejects the veneer piece very rapidly from the conveyors 25. This back pressure cuts the suction being applied to the veneer instantly. On the other hand, if damper 115 is used in the apparatus, the suction of fan 100 is cut off when the damper is closed, but the suction is not instantaneously cut off from the veneer that has just been attracted to the transport belt. In other words, the veneer piece does not drop off the belts as fast as it does when damper 110 is employed. As a result, infeed conveyor has to be operated at a slower speed then when damper 110 is used. The big advantage'of the latter'damper is that it simultaneously cuts off th suction and applies'the back undersized veneer piece.
Although apparatus can be. used for sorting or classifying veneers of'different widths, it is primarily intended for separating good veneers from scrap veneer following the action ofa veneer clipper. In actual practice, the signals that cause the clipper to operate can be used to control suction means 96 of the apparatus.
FIG. 7 illustrates apparatus that can be used to separate veneers from trimmings, and to separate good veneers of different widths. This embodiment includes apparatus 10 with its infeed belt 14 and outfeed belt 18, and a similar. apparatus 10a in which conveyor 18 acts as the infeed conveyor, and. another similar conveyor pressure to repel the -125 acts as the outfeed conveyor therefor.
Apparatus 10a functions in the same manner as apparatus 10. If sensor 76'detects a veneer of a width beyond a predetermined width, it signals to apparatus 10a to cause the primary suction thereof to attract the piece to transport belts 40 so that. it is carried over gap 20a and deposited on to conveyor 125. If the sensor detects a piece having a smaller width but wider than the predetermined minimal width, the primarysuction is cut offand the piece is allowed to drop through gap 20a. It is usually desirable to provide a receiver 130 at this gap so as to receive these pieces.
It is obvious that the apparatus may have as many units 10 in succession in order to accomplish adesired degree of classification of .the veneer pieces.
, As pointed out above, an important feature of this invention is the use of damper in the outlet duct of the primary suction fan. This, when closed, creates the almost instant back pressure which rapidly separates the non-selected piece from the transport belts. Efforts have been made in the past to use suction to attract sheet material to belt conveyors and to release the sheets by cutting off the suction and applying pressure in an attempt to accomplish this action in a rapid manner. However, the known apparatus requires two separate systems, the suction system and a pressure system, and this requires space and comparatively costly elements in the two systems. In addition, when attempts are made to cut off suction and apply pressure, there is also difficulty of balancing these correctly, and even when they are correctly balanced, they are relatively slow since it takes time to move pressure valves relative to suction valves.
1. Apparatus for separating pieces of sheet-like material having at least predetermined marginal dimensions from other pieces of less than the predetermined marginal dimensions, said apparatus being adapted to be used in association with sensing means which is operable to sense the dimensions of pieces being directed to the apparatus, said apparatus comprising an infeed convenor, an outfeed conveyor having an end adjacent but spaced from an end of the infeed conveyor to leave a gap therebetween, a transport conveyor above and extending between the adjacent conveyor ends and having from and rear ends respectively overlapping and above the infeed and outfeed conveyor ends, means for applying primary suction to the front end of the transport conveyor over the infeed conveyor to attract pieces from the infeed conveyor to the transport conveyor, means for applying secondary suction to the transport conveyor from near the front end thereof to near said rear end and over said adjacent end of the outfeed conveyor, and means responsive to said sensing means for selectively shutting off and applying said primary suction to attract or not to attract pieces to the transport conveyor in accordance with the dimensions of the pieces, said secondary suction retaining attracted pieces on the transport conveyor while the latter transports said pieces to the outfeed conveyor, and nonattracted pieces dropping into said gap.
2. Apparatus as claimed in claim 1 in which said means for applying primary suction comprises a suction fan having an inlet duct and an outlet duct, and said means for shutting off and applying said primary suction comprises a damper in said outlet duct, whereby the closing of said damper in the duct cuts off the primary suction and simultaneously creates an instant and momentary back pressure to repel pieces from the transport conveyor.
3. Apparatus as claimed in claim 1 in which said means for applying primary suction comprises a suction fan having an inlet duct and an outlet duct, and said means for shutting off and applying said primary suction comprises a damper in said inlet duct, whereby the closing of said damper cuts off the primary suction to allow pieces to fall away from the transport conveyor.
4. Separating apparatus as claimed in claim 1 wherein said sensing means comprises a plurality of photo electric cells across and below and extending longitudinally of the infeed conveyor, and light means above said conveyor and directed on to said cells.
5. Separating apparatus as claimed in claim 1 wherein said transport conveyor comprises a plurality of parallel laterally spaced endless belts, and said secondary suction means extends longitudinally along at least some of the belts and is positioned to suck attracted pieces against said belts to be moved thereby.
6. Separating apparatus as claimed in claim 1 wherein said transport conveyor comprises a plurality of parallel laterally spaced endless belts, said belts being arranged in closely spaced pairs to form narrow spaces therebetween, and said secondary suction means comprises a closed suction box having slots therein opening into the narrow spaces between portions of pairs of belts against which the pieces bear while being transported by said belts.
7. Apparatus as claimed in claim 6 in which said means for applying primary suction comprises a suction fan having an inlet duct and an outlet duct, said inlet duct being in communication only with said narrow spaces between said pairs of belts, and said means for shutting off and applying said primary suction comprises a damper in said outlet duct, whereby the closing of said damperin the duct cuts off the primary suction from the narrow spaces between the pairs of belts and simultaneously creates an instant and momentary backpressure in said spaces to repel pieces from the transport conveyor.
8. Apparatus as claimed in claim 6 in which said means for applying primary suction comprises a suction fan having an inlet duct and an outlet duct, and said means for shutting off and applying said primary suction comprises a damper in said inlet duct, whereby the closing of said damper cuts off the primary suction to allow pieces to fall away from the transport conveyor.