US2623587A

US2623587A - Veneer clipper

Info

Publication number: US2623587A
Authority: US
Inventors: David E Hervey
Original assignee: HERVEY FOUNDATION Inc
Current assignee: HERVEY FOUNDATION Inc
Priority date: 1946-08-27
Filing date: 1946-08-27
Publication date: 1952-12-30
Anticipated expiration: 1969-12-30
Also published as: FR2143302B1; FR2143302A1

Description

D. E. HERVEY VENEER CLIPPER Dec. 30, 1952 Filed Aug. 27 1946 5 Sheets-Sheet l INVENTOR. D- E. HERVEY I I) a:

ATTORNEY D. E. HERVEY VENEER CLIPPER Dec. 30, 1952 .5 Sheets-Sheet 2 Filed Aug. .27, 1946 INVENTOR. D. E HERVEY ATTOR NEY Dec. 30, 1952 D. E. HERVEY 2,523,587

VENEER CLIPPER Filed'Aug. 2'7, 1946 5 Sheets-Sheet 5 II III u: .0 Ii ,11

| 1 1 1 l E Z I I I. Ill Ill/1115.7

ATTORNEY I'll III I Illil/l/ i FIG IO FIG 11 I i i i I ii 120 no r l SPF/N6 500 2 Il HH HI FIG. 12

CONTROL 70 .56, FIG. 8 F01? Patented Dec. 30, 1952 David E; Hervey, Old Fort, N. 0., assignor to Hervey Foundation, Incorporated, a corporation of Maryland Application August 27, 1946, Sei-ia lNo.'693;2 41 2 Claims. (01. 164 42) This invention relates to improvements in wood veneer manufacturing and particularly to an improved method and improved apparatus for dividing large sheets of wood veneer into veneer pieces in accordance with the various grades of veneer wood contained in the veneer sheets as they are removed from the logs, and for stacking the pieces and conveying them away from the veneer cutting equipment.

It is customary to produce wood veneer by turning logs in a lathe against a straight veneer cutting knife having feed mechanism associated therewith which feeds the knife into the wood at a rate to produce a continuous sheet of veneer of uniform thickness. The thickness may be varied when desired by changing the feed rate of the knife. As the sheet of veneer is removed from the log it is placed upon a conveyor which continuously moves it away from the lathe. A sheet of veneer as removed from the log usually contains defects such as cracks, knot holes and decay which were present in the log from which the sheet was cut and these defects recur at substantially constant intervals in the veneer sheet as determined by the length of veneer sheet removed during one revolution of the log. These intervals are not completely uniform, however, as they will become shorter as the diameter of the log is reduced; In order to avoid substantial waste of usable wood, the defective material in a veneer sheet must be cut away in such a manner that a minimum amount of clear material is included in the pieces containing the defective material. According to present practice, as the sheet of veneer leaves the lathe it is torn across at intervals by a lathe attendant; The pieces of veneer sheets so produced may be comparatively long or, particularly where the Wood contains numerous defects the attendant may tear the sheet across at each revolution of the lathe producing a number of comparatively short pieces of veneer. Where the long pieces are produced, they may be transported in this condition to a veneer clipper by means of which they are cut into pieces of desired lengths and the portions containing imperfections are cut out and discarded. It is the more common practice, however, to tear the sheet into the short pieces and stack these pieces one on top of the other to form a book. In forming the "{book an attempt is made to match the imperfections throughout the stack so that the entire stack of pieces can be clipped together to remove the portions containing the imperreeucnsam divide the nea wood into pieces of desired length; It has not been found possible, however; to match the imperfections in such a book to any satisfactory degree and an excessive amount of clear wood is contained in the cut out portions containing the imperfections, while some imperfect Wood is left in the pieces of clear or usable material. This method may result in a loss of usable wood of anywhere from 10 to per cent.

Where it is attempted to handle the long pieces of veneer and use the clipper to out only a single thickness the loss of time and labor is excessive and there is also an unnecessarily large loss of usable wood.

Due to the infinite variety of defects, the infinite number of dimensions between them, and the ever changing grade specifications for the veneers produced, the conventional practice, :as briefly outlined above, inevitably results in excessive loss of time and excessive waste of usable material.

It has also been found impossible to properly grade the material when produced according to conventional practice while at the same time keeping production at a high level. The capacity of the clipper is a great deal less than the capacity of the log turning lathe so that the clipper operator is working at all times under extreme pressure and even with his best effortit is frequently necessary to shut down the entire veneer cutting operation to prevent piling up an excessive overload of veneer on the conveyor between the lathe and the clipper. While working at top speed, the clipperman finds it impossible to accurately stop the veneer sheet at exactly the right point each time and the instantaneous decisions he must make with regard to grading and saving of material prove extremely fatiguing to the operator, wasteful of material and results in confusion of grading and production materially below the potential capacity of the equipment.

While veneer clipping machines have been proposed and utilized in the past these" have proved unsatisfactory for various reasons and consequently the manual operations as described above are still extensively used in veneer producing operations and applicants invention is intended to eliminate these manual operations and to materially contribute to the rapid and economical production of veneer.

Up to the present time very little has been done to relieve this situation. Increasing the conveyor automatic multiple knife clipper with knives operated at 2" intervals by push button control has been proposed. This minor change in the conventional practice has, however, had no important effect in solving the various problems indicated above, as it cannot materially decrease the waste and frequently results in a definite increase, and can produce only veneer pieces of a definitely limited small number of sizes.

The conventional practice, as is clearly apparto carefully inspect the veneer before it is cut,

make definite decisions as to the location of the lines along which the sheet is to be cut into pieces suitable for use, for marking or indicating these lines so that the veneer sheet will be automatically out at the desired intervals or, in cases where only one size or grade of Veneer is involved, to predetermine the exact size of the pieces and set the clipper for automatic operation to cut the sheet into pieces of uniform size as may be desired; and to accomplish the surveying, marking a and cutting of the veneer into pieces according to grade specifications or predetermined size without at any time stopping the operation of the veneer cutting lathe or interrupting the movement of the veneer sheet along the conveyor and through the clipper.

A further object resides in the provision of improved veneer manufacturing method and apparatus wherein the severed pieces of veneer are automatically stacked into stacks containing predetermined amounts of veneer and the stacks are automatically conveyed to predetermined points of discharge, such as locations adjacent to drying kilns. A still further object resides in the provision of an automatic veneer clipper of simple and durable construction capable of high speed operation under automatic control and which does not interfere with the movement of veneer along the conveyor leading to the clipper and through the clipper. Y 7

Another object resides in the provision of an aligning means extending across the veneer carrying conveyor providing lines parallel to the clipper knife to assist the operator in properly laying off the veneer sheet into pieces of sound material of maximum area and in providing a method of measuring the veneer sheet and separating it into units of uniform arrangement of predetermined amount. 7

Yetanother object resides in the provision for reclipping the pieces of Veneer which result from the foregoing operations wherein they are severed either longitudinally with or perpendicularly to the direction of the grain either before or after the pieces are dried.

Other objects and advantages will become apparent from a consideration of the following description taken in conjunction with the accompanying drawings, wherein:

Fig. l is a plan view of veneer manufacturing apparatus illustrative of the invention;

Fig. 2, an elevational view of a fragmentary portion of the apparatus illustrated in Fig. 1;

Fig. 3, a detailed isometric view of a projector 4- for projecting a moving pattern of grid lines onto the veneer on the conveyor and suitable supports for the projector;

Fig. 4, a detailed isometric view of a set of fixed parallel lines extending across the conveyor and means for supporting them;

Fig. 5, a detailed isometric view of an electromagnetic pick up and clipper actuating switch;

Fig. 6, an isometric View on an enlarged scale of the switch means illustrated in Fig. 5;

Fig. 7, a plan View of a piece of veneer wood strip showing the manner of locating marking bars thereon so that imperfections in the sheet will be removed by the clipper;

Fig. 8, an elevational view of the veneer clipper showing a switch for automatically operating the clipper to cut the veneer into pieces of predetermined size;

Fig. 9, a view similar to Fig. 8 showing the clipper mechanism in a different operative posi-- tion;

Fig. 10, an elevational view of a modification of the clipper and adjacent portion of the conveyor showing a photoelectric device for operating the clipper in accordance with marks placed on the surface of the wood veneer;

Fig. 11, a plan view of a piece of wood veneer showing the manner of marking the veneer for removal of imperfections by the veneer clipper;

Fig. 12, an elevational view of another modification of a veneer measuring and clipper actue ating device for measuring the wood veneer ahead of the clipper and automatically actuating the clipper to out the Wood into pieces of predetermined size.

With continued reference to the drawings and particularly to Fig. 1, the conveyor 2 is operatively positioned between a veneer cutting lathe 3 and a veneer clipper 4. The lathe 3 may be of the form shown in my copending application Serial No. 691,919, filed August 21, 1946 for Wood Manufacturing, and the conveyor may be a conventional chain conveyor having three or more endless chains 5 carried on sprockets mounted on end shafts as indicated at 6 and driven at a substantially constant speed by power means, such as an electric motor, not illustrated. The chains may be supported between the end shafts by suitable idler sprockets or rollers in a manner well known to the art.

As the veneer is cut from the log in the lathe 3 it falls upon the conveyor 2 and is carried along the conveyor in the form of a strip to the clipper 4. The length of the conveyor between the lathe and the clipper is made sufiicient to provide an inspection station for the veneer strip so that an attendant may carefully inspect the veneer while it is on the conveyor, have suflicient time to properly estimate the various grades of veneer in the strip and lay the strip off into suitable pieces according to the various grades present. In order to facilitate the inspection of the veneer suitable illumination is provided in the form of lamps as indicated at l and-8, carried by suitable respective supports 9 and I0 at a proper height above the veneer tto provide the most desirable illumination. Between the lamps 1 and 8 a projector unit I! is mounted on a support I2 and is driven through a suitable drive connection l3 from the conveyor to project a moving grid pattern of parallel lines onto the surface of the veneer as it passes under the projector. These lines enable the inspector or attendant to imveneer along which the inspector is working so that he may conveniently mark the places at which the veneer is to be severed by the clipper. The drive connection l3 may be of a flexible drive cable for example, such as a tachometer drive shaft of conventional construction.

By driving the flexible shaft I3 from the conveyor, through any desired type of variable speed gearing, the lines of light projected from the unit ll onto the travelling sheet of veneer may be made to move with the sheet at synchronous speed, thus giving the attendant adequate opportunity to make the desired marks.

The projector and supporting means therefor is illustrated in somewhat greater detail in Fig. 3 and may include a moving screen or other equivalent means to project moving lines of light.

Suitable fixed transverse lines M are provided across the conveyor adjacent to the clipper 4, a suitable construction for these lines being illustrated in Fig. 4.

As illustrated in Fig. 4, the support it for the lamp 8 has two portions I5 and 15 disposed one at each side of the conveyor 2 and each comprising two spaced apart legs or standards. Respective guide members ill and I8 are carried by the support portions l5 and it at opposite sides of the conveyor slightly above the top surface of a strip of conveyor supported veneer and substantially parallel to the veneer strip. Respective slide blocks it and 23 are slidably mounted on the guide members ll and I8 and may be secured in adjusted position thereon by suitable means such as set screws as indicated at 2|. A plurality of parallel wires 22 are secured at their ends to the blocks l9 and 2E) and stretched between the blocks and are positioned below the lamp 8 in such a manner that the lamp will cast definite shadows of the wires onto the surface of the veneer to provide the guide lines It. By means or" these fixed guide lines the operator or inspector can check the positioning of the severing indications he has placed on the veneer and may also use these fixed guide lines for manual control of the clipper if that form of operation should be desirable. For example, if itwere desired to use the clipper to trim the ends of pieces already severed from the veneer strip, the pieces could be clipped to desired uniform length by using these fixed guide lines as a measuring scale to determine the distance from the end of the piece to the clipper.

A suitable method of placing marks or indications on the veneer sheets to predetermine the locations at which the veneer is to be severed by the clipper is illustrated in Figs. 5, 6 and 7.

In the example shown in Fig. 5, suitable bars of magnetic material, such as steel, of relatively small cross section are secured together in pairs of parallel bars by suitable flexible connectors or straps. The bars of one such pair are indicated at it and 2t and the flexible connectors at 25 and 26. The pairs of bars may be provided in sets in which the various sets have different length connectors so that the bars will be spaced at various predetermined distances apart. Such pairs of bars may be laid on the edge of the veneer at uniform intervals to produce veneer pieces of uniform desired size or may be used to indicate relatively narrow portions of defective material which are to be removed from the veneer.

A device, generally indicated at 21, for removin the bars from the veneer is located immediately above the conveyor and in front of the clipper 4. This device may include a pair of spaced

parallel rollers

28 and 29 surrounded by a continuous flexible belt 30 of fabric or some other suitable material. The roller 28 is driven at a speed such that the belt 30 moves at substantially the same speed as the conveyor chains 5 and may be driven from the conveyor chain drive or by a friction band 30a in contact with the surface of the veneer. The roller 29 contains a series of electromagnets having sufiicient force to pick the bars of electromagnetic material up from the surface of the veneer and carry them around the roller and onto the upper surface of the belt 36 from which they are deposited into a receptacle 3 I.

As the bars pass along the top of the belt 39 they contact a switch device, generally indicated at 32, comprising a plurality of rollers 33 of electric conductive material supported on a tubular shaft as and insulated therefrom. At one end the shaft carries a pair of slip rings 35 and 3G and wire leads 3? and 38 connect alternate rollers 33 to the respective slip rings. With this arrangement, whenever an indicating bar is brought in contact with two adjacent rollers it will complete that portion of an electric circuit including the slip rings, the wires 37 and 38, and a pair of brushes 39 and is. The brushes are electrically connected by

wires

39a and 40a to a relay mechanism it which is in turn electrically connected, in any suitable manner, by wires Ma and Mb with the clipper so that the clipper is actuated to sever the veneer whenever one of the bars contacts a pair of therollers 33.

As illustrated in Fig. '7, single bars may be used instead of the connected pair of bars shown in Fig. 5. When the single bars are used they are laid along one edge of the sheet of veneer in position to mark the locations at which the veneer is to be severed by the clipper to remove portions containing imperfections or to divide the strip of veneer up into pieces according to the various grades of veneer wood contained in the strip. After the bars, as indicated at 42 in Fig. '7, are laid in position on the veneer by the veneer inspector they move along the veneer and under the belt 36 and are picked up by the electromagnetic means 29 and brought to a position at which they contact rollers 33 of the switch mechanism 32. The position of the switch mechanism is such that at the instant a bar contacts the switch rollers, the position at which the bar was placed by the inspector will be directly under the clipper knife- The bars pass under the switch rollers and continue along the belt 30 until they are deposited in the receptacle 3! from which they may be removed by the inspector for reuse as the process of dividing the veneer strip up into suitable pieces continues. A suitable clipper for severing the veneer strip is shown in Figs. 8 and 9. Such a clipper may be of relatively simple form having a frame comprising a pair of vertical standards 44 and rigidly mounted on a suitable base 46 and connected at their upper ends by a top beam or plate 41'. Intermediate the height of the vertical members a shaft 43 is pivotally supported thereby and carries a pair of parallel arms as indicated at so to the outer end of which is adjustably connected a knife bar or bracket 50. The bracket to carries a clipper knife 5! which cooperates with the edge of a fixed shear plate 52 to sever the veneer strip whenever the clipper isactuated. The shear plate is carried at the upper end of suitable standards 53 connected by brack ets as indicated at 54 to the standards indicated at45 to constitute a rigid frame for the clipper. The bracket member 55 suspends from the top plate 41 and pivotally supports a two-way electromagnet 56, the armature of which is connected by suitable link 51 with a knife supporting arm i9. There are preferably two similar electromagnets located one at each side of the frame and operatively connected with the respective knife supporting arms. The actuating circuit for the solenoids is such that when the clipper control switch or relay M is closed the solenoids 56 move the clipper downwardly to sever the veneer but when the knife reaches its lowermost position this circuit is automatically broken and a different circuit established which energizes the solenoids to quickly raise the knife and hold it in its raised inoperative position until the actuating switch is again closed.

A suitable veneer guide 58 is positioned above the shear plate 52 to guide the ends of the veneer and prevent the knife from raising the end of the veneer strip as the knife returns to its upper position and to insure that the strip after being severed will continue to pass beneath the knife and through the clipper.

A tiltable rack 59 pivoted at its forward end, as indicated at 60, receives the pieces of veneer as they are severed by the clipper and deposits them onto a belt conveyor, generally indicated at El, which carries the veneer pieces away from the clipper and to suitable locations from which they may be placed in drying ovens or kilns, as indicated at 62, 63, and 64 in Fig. 1.

The rack or table 59 has its pivoted forward edge disposed somewhat below the upper surface of the shear plate 52 so that as the pieces are cut from the strip they will drop onto the table. This table is urged to its upper or substantially horizontal position, as illustrated in Fig. 8, by a suitable compression spring 65 and is moved to its lower or tilted position, as illustrated in Fig. 9, by suitable means such as the solenoid 66.

At its end adjacent the clipper the conveyor 6| is supported on a roller 61 having an axle 58, the ends of which are guided in vertical slots in respective end blocks 69 and Hi. The axle is urged to its uppermost position by suitable calibrated springs II and i2 and is moved downwardly by the weight of veneer pieces stacked thereon by the clipper table 59. When the roller 67 has been moved downwardly a predetermined amount corresponding to a desired weight of veneer pieces, a pair of electric contacts i3 and 14, Fig. 9, are brought together to close the electric circuit energizing the motor '55 (Fig. 1) which drives the conveyor 5|. Energization of the motor will continue until the veneer pieces have been brought to the desired position along the conveyor and will then cease either automatically or under control of a manual switch, as hereinafter more fully explained.

As it is desirable that the clipper table 59 should not deposit any veneer pieces on the conveyor while it is in motion, a relay switch 16 is provided in the circuit which controls the solenoid 66 so that this solenoid cannot be energized as long as the circuit energizing the motor 15 is closed. During this interval veneer pieces will pile up on the clipper table and will be discharged therefrom as soon as the motion of conveyor 6| ceases.

As illustrated in Figs. 8 and 9, means are provided for automatically cutting a large number ojveneer pieces to the same size. This means may conveniently include a spring switch Tl mountedon a horizontal scale arm 18 extending outwardly from the clipper frame. This switch may be held at any selected position along the scale arm by suitable means such as the set screw 19. A lever 89 extends downwardly from the switch in position to be contacted by the leading edge of the veneer strip passing through the clipper. The edge of the veneer strip will movethe lever sufiicient to close the switch which will then complete a circuit from the line wires 8| and 82 through the solenoid 56 and cause the clipper knife to operate. While the switch 11 is in operation it may be desirable to discharge each piece of veneer from the clipper table 59 onto the conveyor Bl. In order to accomplish this a lead 83 from the switch wire 84 leads to the solenoid 99 completing the side of the circuit from the line 8| to the solenoid and a second wire 85 leads from the solenoid to the wire 82 so that the solenoid 65 is energized each time that the switch I1 is closed. As explained-above, these circuits are automatically interrupted when the clipper knife descends so that the spring 55 will immediately return the table to its upper and horizontal position. A manual switch 86 is preferably included in the wire 8! leading from wire Bl to switch Ti so that switch I! may be put out of operation when desired.

When the switch H is not in operation the clipper table may be operated by other clipper control means such as the switch 32 shown in Figs. 5 and 6 and will operate in the same manner to deposit the veneer pieces onto the conveyor 6! while the conveyor 6| is not in motion and to retain the pieces during motion of the conveyor BI and deposit them onto the conveyor as soon as the conveyor motion ceases.

In Figs. 1, 8 and 9 portions of suitable wiring circuits are shown, and it will be seen that the circuits of Figs. 8 and 9 are specifically different. Thus, in Fig. 8, power supplied through a suitable control panel through the line wires L-l and L-2 to the solenoids 56, and also through a retarding circuit taken through the branch lines 65a and 65b to the solenoid 66. It will, of course, be understood from the previous portion of the description that the solenoid 6B is actuated after the knife 5i has severed the sheet, and accordingly the electrification should be such as to delay the energization of the solenoid 66 until after the solenoids 56 have performed their function.

In Fig. 9, a variation of the circuit is shown to incorporate the micro-switch T! which is employed when it is desired to cut the veneer into pieces of the same length. Inasmuch as this circuit has already been described, it need not be retraced. A suitable control circuit for the motor 75 and cutout relay 16 is more or less schematically illustrated at the lower portion of Fig.

1. In passin to this figure, it may be noted that the relay 15 may be of the type which is energized whenever the motor 15 is runnning, and the energized position is shown in Fig. 9.

According to Fig. 1, power for the motor 75 may be supplied manually from the line wires L-! and L-Z through the switch 8-! upon closing this switch, thus giving direct and independent control of the motor whenever desired. Manually controlled switch 8-2, when closed, makes power available for the motor 15 through the armatures of a relay R-l, which is in the circuit leading from the contactor points 73 and 14 and associated wires 13a and 14a, shown in Fig. 9. It has also been pointed out that it may be desirable to provide automatic cut-off for the motor when the conveyor 6| has moved a pretermined distance. Such control may be effected mechanically by a lug Bla clipped to the side of the conveyor belt, and which can trip the arm C-I of a normally closed control switch C, bodily movable to any desired position along the conveyor stretch. This circuit may briefly be described as follows;

Upon the closure of contact points I3 and it under the weight of the sheets, current flows from a low voltage localized source of current, designated by the letter B, into the coil of relay R-i, normally closed contacts of switch (3', and thence through the coil, armature and one contact of a holding relay R-Z into the line Ma, through contacts M and I3 and wire 73a to the current source B, thereby completing an ener izing circuit for both relays R-I and R4. The armatures of relay R-I then close against their contact points to supply current from the lines L4 and L42 directly to the motor 75 through a circuit which by-passes manual switch S-I.

As the load of veneer sheets moves away from the spring-separated contactors l3 and M, these contactors will open. However, upon energization of relay R4, its armature moves to an opposite contact connected to. line wire 13a, and thence into local current source B, thereby maintaining energization of relay R-'I and Joy-passing contactors I3 and 74. As indicated in Fig. 9, current is supplied to relay [6 by tapping into lead ltd and through an auxiliary line 79a. Line its, as shown in Fig. 1, may be connected to line wire L-2 adjacent the motor I5, while line Ta may be connected through a suitable resistance and a feeder line 76b to line L-I. Hence, whenever current is supplied to the motor 75, relay It will be energized and operation of the solenoid 95 thereby forestalled. It will further be apparent that when the lug BIa strikes the arm CI to open the contacts of switch C, the local circuit through relay R-2 will be broken, thereby deenergizing both relays R-I and. 13-2 to stop the motor I5, deenergize relay I6, and restore the circuits to the condition they were assumed to be in at the outset of this summary.

An alternative method for indicating the locations at which the strip is to be severed is illustrated in Figs. and 11. This method uses the same moving grid pattern and fixed grid pattern as described above but instead of placing bars of magnetic material on the surface of the veneer strip the locations at which the strip is to be severed are marked with a suitable material such as chalk. The chalk may be applied directly by hand or may be applied by a device such as that generally indicated at 89. This device comprises a stand 89 which supports a powder container 9i) immediately above the conveyor at one edge thereof. A discharge nozzle 9| leads from the container and an air bulb 92 is connected to the container in such a manner that manual pressure on the bulb will discharge a sufficient quantity of chalk or other powder through the nozzle 9i to make a line on the surface of the veneer.

A combined light projection and photoelectric device, generally indicated at 93, is positioned above the conveyor at a location such that it will be focused on the chalk marks or lines as they pass beneath the device at or near the location at which the clipper knife severs the veneer. This device is mounted on a suitable support, gen.- erally indicated at 94, and is electrically oonnected with the solenoid 56 by suitable connectors and 9B. Leads 91 and 93 connect the device itself with the line wires 99 and I99 and a manual switch I9I is incorporated between the device and the solenoid so that the device may be put out of operation when its service is not desired. For simplicity in illustration, the actuating solenoid for the rack 59, and the conveyorfor removing the sheets, have not been illustrated, as it is obvious that they may be included in the manner previously explained, if desired.

Preferably the photoelectric device is made color sensitive so that it will respond only to a predetermined color of chalk or other mark and will not respond to any variations of color or light reflecting characters of the wood itself.

Fig. 11 shows a manner in which marks may be located to eliminate the imperfections from the veneer, the marks being indicated at I92 on the veneer strip I03. However, the device may be used for dividing the veneer strip into pieces of equal size or into pieces of measured length.

In Fig. 12, there is illustrated a modified arrangement for automatically dividing the veneer strip into pieces of uniform desired size. In this arrangement, a frame I04 is pivotally connected to a suitable standard or support I05 adjacent one side of the conveyor by suitable hinge connections I09. Above the hinge connection the bracket I04 has a pair of arms I01 and I98 extending lengthwise of the conveyor in opposite directions, the arm I08 being materially longer than the arm I91 and being provided with an elongated guide slot I09. A roller Hill is journalled in the end of the arm I91 and a corresponding roller III is journalled on a guide block H2 slidable in the guide slot I09 and adjustable along the guide slot by means of a screw shaft II 3 operated by a hand crank H4. An endless belt I I5 of flexible material such as rubber passes around the two rollers H9 and III and carries one or more projections, as indicated at H6, positioned to actuate the lever I I! of a spring switch H8 connected by suitable wire leads H9 and I29 with the clipper solenoid 56.

The rollers H9 and II I rest, when the device is in operative position, upon the surface of the veneer strip so that the belt H5 is driven at the same speed at which the strip moves through the clipper. By changing the length of the belt the intervals at Which the projection II 6 trips the switch I I8 can be varied so that veneer pieces of desired length can be out. The length of the piece to be cut is accurately determined. by means of a scale I 2| along one side of the guide slot I 99 and a pointer I 22 on the slide block H2.

By means of the above described arrangement, a strip of wood veneer or other sheet material can be divided at will into pieces as determined by the various grades of material in the strip or can be automatically divided into pieces of desired uniform length regardless of grade variation. The operation of the clipping mechanism is entirely automatic and is of sufiicient speed that the clipper will at all times keep pace with the veneer cutting lathe and there will not at any time be any necessity for discontinuing operation of the lathe to permit the clipper to catch up.

If desired, two sets of the above mechanism may be used adjacent to one lathe, which mech anism may be used simultaneously or alternately as operating conditions may require.

It will be obvious to those skilled in the art that various changes may be made in the invention without departing from the spirit and scope thereof and therefore the invention is not limited by that which is shown in the drawings and described in the specification but only as indicated in the appended claims.

What is claimed is: V

1. In sheet cutting apparatus, a conveyor for supporting and movin a strip of sheet material; a sheet clipper at the discharge end of said conveyor; bars of magnetic material placeable on said strip to determine locations at which the strip is to be out; electromagnetic means associated with said conveyor for removing said bars from the strip of sheet material; and switch means operatively associated with said electromagnetic means operable by said bars to actuate said clipper in accordance with the location of said bars on said strip of sheet material.

2. In sheet cutting apparatus, a conveyor for supporting and moving sheet material; a sheet clipper at the discharge end of said conveyor; means placeable on said sheet material to determine locations at which the strip is to be cut comprising pairs of bars of magnetic material held in parallel spaced relationship to each other by flexible connectors; electromagnetic means associated with said conveyor for removing said bars from the strip of said material and switch means operatively associated with said electromagnetic means operable by said bars to actuate said clipper to sever said sheet material into pieces corresponding in size to the spacing between each pair of parallel bars.

DAVID E. HERVEY.

12 REFERENCES CITED UNITED STATES PATENTS Number Name Date 1,127,975 Elwing Feb. 9, 1915 1,150,541 Ryan Aug. 17, 1915 1,440,383 Fenlason Jan. 2, 1923 1,565,840 Wise Dec. 15, 1925 1,566,701 Schumacher Dec. 22, 1925 1,629,522 Munroe May 24, 1927 1,686,088 Horstkotte Oct. 2, 1928 1,757,204 Magill May 6, 1930 1,819,991 Stevens Aug. 18, 1931 1,841,853 Stanley Jan. 19, 1932 2,077,439 Schmitt Apr. 20, 1937 2,086,374 Wikle' July 6, 1937 2,151,570 Shoults Mar. 21, 1939 2,171,667 Mickelson Sept. 5, 1939 2,193,259 Sheperdson Mar. 12, 1940 2,222,842 Humphrey Nov. 26, 1940 2,286,686 Muddiman June 16, 1942 2,338,596 Pitt 1 Jan. 4, 1944 2,341,011 Basoom Feb. 8, 1944 2,379,682 Colucci July 3, 1945 2,382,801 Maurer Aug. 14, 1945 2,394,558 Miller Feb. 12, 1946 FOREIGN PATENTS Number Country Date 42,697 France June 12, 1933 480,224 Great Britain Feb. 18, 1938