US2928305A

US2928305A - Veneer clipper for cutting measured lengths with means responsive to feed of work to regulate the cutting cycle

Info

Publication number: US2928305A
Application number: US633857A
Authority: US
Inventors: Edwin M Heth; Arthur W Rickford
Original assignee: PRENTICE MACHINE WORKS Inc
Current assignee: PRENTICE MACHINE WORKS Inc
Priority date: 1957-01-14
Filing date: 1957-01-14
Publication date: 1960-03-15
Anticipated expiration: 1977-03-15

Description

March 15, 1960 E. M. HETH ETAL 2,928,305

VENEER CLIPPER FOR CUTTING MEASURED LENGTHS WITH MEANS RESPONSIVE To FEED OF WORK T0 REGULATE THE CUTTING CYCLE Filed Jan. 14, 1957 3 Sheets-Sheet l INVENTORS Edwin M.He'l'h Hrlhur WRickf'ord .Ez 6. l J 2%.

March 15, 1960 E. M. HETH ETAL 2,928,305 VENEER CLIPPER FOR CUTTING MEASURED LENGTHSWITH MEANS RESPONSIVE T0 FEED OF WORK TO REGULATE THE CUTTING CYCLE INVEQTORS n MHeH'z 2 m 5 w w a 3 Nm Nm g ww.

i z m Filed Jan. 14, 1957 March 15, 1960 E. M. HETH ET AL 2,928,305

VENEER CLIPPER FOR CUTTING MEASURED LENGTHS WITH MEANS RESPONSIVE T0 FEED OF WORK TO REGULATE THE CUTTING CYCLE 5 Sheets-She et :5

Filed Jan. 14, 1957 INVENORS .E cl W1- n MHe i-h HI' i'h ur Wlfickzbrd Unite States Pateitit D VENEER CLIPPER FOR CUTTING MEASURED LENGTHS WITH MEANS RESPONSIVE T FEED 0%; WORK T0 REGULATE THE CUITING C OLE Edwin M. Heth and Arthur W. Rickford, Portland, 0reg., assignors to Prentice Machine Works, Inc., Portland, Oreg., a corporation of Oregon Application January 14, 1957, Serial No. 633,857

11 Claims. c1. 83-399) This invention relates to veneer clippers such as are employed in the lumber industry to clip or cut continuous sheets of veneer or partsthereof into pieces of prese lected lengths and control means for such veneer clippers;

An object of the invention is to provide a veneer clipper wherein actuation of the blade in the clipper is regulated by mechanism which is readily controllable and which may be finely adjusted to produce regular veneer segments of preselected length.

It is another object of the invention to provide a novel control means for a veneer clipper blade which actuates the blade of the clipper for a cutting pass after a delay interval measured by a control member moving unidirectionally in determining the delay interval and initiated in its unidirectional movement at the instant that the clipper blade undergoes a cutting pass.

Still further, it is an object of this invention to provide, for a veneer clipper mechanism having a clipper blade and reciprocating power means for moving the clipper blade in a cutting pass, novel control means for such a mechanism wherein each stroke of the reciprocating power means is controlled by an independent control unit, thereby to accommodate a maximum amount of aizcuracy in the control and regulation of the clipper b ade.

Conventional veneer clipper mechanism comprises suitable conveyer means for feeding a continuous veneer sheet through the mechanism and a clipper blade mounted for a rapid cutting pass comprising a downward movement into the sheet of veneer followed by a rapid return stroke. A continuous sheet of veneer is cut into predetermined lengths by the operation of the clipper blade, the segmented veneer then being transported for further processing into a variety of different lumber products. To eliminate waste and off-cut sizes, it is highly desirable that the clipper blade be actuated in its downward stroke at precise intervals measured by the passage of veneer through the clipper mechanism. If the veneer is traveling at any appreciable rate, a slight variation in the timing of the downward stroke results in considerablevariation in the length of the cut created by the cutting pass of the blade. For this reason, a need for a highly accurate control means has arisen. In addition to cutting off lengths of sheet at preselected Intervals, the means controlling the clipper blade should be adjustable so as to accommodate the cutting of both long and short sizes of veneer segments. In this manner, a short piece of veneer may be cut from a veneer sheet if it is desired to eliminate a flaw, or the lengths of the veneer segments may be varied depending upon the ultimate use of the veneer pieces.

Many of the present day clippers employ a clipper blade mounted so that the clipper blade undergoes a full reciprocation, that is, a downward and retractile movement, for each stroke of a reciprocating power mechanism operating the blade. Thus, two complete cutting passes are made by the blade for each complete reciprocation of the power mechanism. Using such a system, an inherently unbalanced condition exists since mechanical irregularities inevitably create a difiierence in the length of time that elapses during the cutting pass of the clipper blade depending upon whether the blade is being actuated by a forward or by a return stroke of the mechanism powering the blade. This unbalanced condition has made it extremely difiicult to regulate the timing of the blade.

Further, regulation of the cutting pass for one stroke of the mechanism powering the blade has tended to affect the cutting pass for the return stroke, each being dependent, to a certain extent, upon the other. 3

More specifically, therefore, it is an object of this invention to provide control means for the clipper blade of a veneer clipper mechanism which incorporates a control member moveable from abase or rest position to a blade activating position, the control member moving from the base to the activating position immediately upon activation of the clipper blade for a preceding cutting pass of the blade. r

A related object is to provide such a control mechanism wherein the control member is moved from its base to its blade activating position at a rate of speed determined by the passage of the veneer sheet through the clipper mechanism, the interval between successive cutting passes of the blade being the interval which elapses from the time the control member leaves its base position to the time it reaches its activating position. a

Another object is to provide control mechanism fora veneer clipper having a control member movable-from a base to an activating position which includes mechanism for returning the control member to its base position after actuation of the clipper blade and means timing the release of the control'member from its base position after its return to the base position, measured from the time of the cutting pass of the clipper blade and not from the time that the control member returns to its 'base position.

Yet another object is to provide for a clipper mechanism av control mechanism comprised of a pair of control units arranged so as to sequentially activate the clipper blade of the mechanism, the interval which elapses during the travel of the control member for one of the units from its base to its blade activating position accommodating the return of the control member for the other unit to its base position.

Still another object is to provide a veneer clipper hav ing a reciprocating power means driving the clipper blade which includes a control unit for each stroke of the reciprocating power. means, the control units operating sequentially and being individually adjustable so that each may be regulated to compensate for irregularities in the operation of the reciprocating mechanism.

Yet another object is to provide, for such a veneer clipper having a pair or" control units for each stroke of the reciprocating power mechanism, control units so arranged that the clipper blade is actuated at intervals determined by unidirectional movement of a control memher in each of the control units.

These and other objects are attained by the present invention various novel features or" which will become more fully apparent as the following description is'read in conjunction with the accompanying drawings wherein:

Fig. 1 is an end view of a veneer clipper mechanism showing a clipper blade assembly having a reciprocating motor means for actuating the blade; I

Fig. 2 is a side view of the apparatus in Fig. 1;

Fig. 3 is a top view of a control mechanism for clipper blade embodying this invention;

Fig. 4 is a side view of the control mechanismillusthe . trated in Fig. 3;

- Fig. 5 is a schematic diagram of the control scenes Patented Mar. 15, 1960. I

. port veneer to and from the apparatus;

tions for the controlmechanism of the invention with various parts shown as symbols to better illustrate the the assembly is a clipper blade assembly-,indicated 'at17.; The clipper blade assembly is conventional, cQmprising floating rods 18 and l9link connected as by toggle links 21 at their upper ends to bar 16 and link connected at their lower ends by toggle links 22 to a-clipper blade 23.. The clipper blade is mounted for reciprocal movement up and down in the apparatus in guides 24 and'26 at opposite sides of the apparatus.

Extending between the inner ends of floating

rods

18 and 19 is a reciprocating power mechanism illustrated as a double acting piston-cylinder device 27 having

piston rods

28 and 29 projecting out of oppositelend's of the piston-cylinder device 27, Attached

tothe rods

28 and 29 are the inner ends of floating

rods

18 and 19. Pistoncylinder device 27 is positioned intermediate the floating rods by brackets 31. Conduits 32, 33 are included at opposite ends of the piston-cylinder deviceto permit the entrance andexhaust of pressure fluid from opposite sides of the piston. i

Beneath the cutting edge of clipper blade 23 is a die member 34. The clipper blade is movable toward and away from the die member for one cutting pass of the blade, piston-cylinder device 27 completing one cutting pass by movement of the piston rods from left to right in Fig. l and completing another cutting passby movement of the piston rods from right to left, in Fig. 1,

Conventional conveyor means are provided to, transin Fig. 2, the veneer sheet is fed to the apparatus by in feedconveyer 37, and segmented veneer is moved out of Ordinarypower the apparatus by outfeed conveyor 35.

Thus, as seen:

circuit interconnects the control units and air pressure valve 39 so that impulsescreated at the pulse generating positions of the control units are employed for regulating the operation of valve 39. One of the control units actuates the forward stroke of piston-cylinder device 27 and the other of the control'units actuates the return stroke of the pistomcylinder device. Each of the control units. isseparately adjustable, and in this mannerthetiming of each stroke of piston-cylinder 27 may be regulated independently of the other stroke. Further, as described hereinbefore, the control units are constructed sothat the control member for one of the units starts moving from its base to its pulsegenerating position so as to measure off a delay interval-simultaneously with actuation of the clipper blade. by the other of. the controlunits. The control member for this other'control unit then returns to its base position and readies itself for measuring off a subsequentdelay interval immediately after actuating the clipper blade. Since each of the control members is given an opportunity to return to its base position before measuring off a delay interval, variations which might arise because of movlng inertia in the control members is eliminated.

,Each of the control uits comprises an elongated guide structure 61 having a planar upper surface 62 and en-. veloping

wall portions

63, 64, and 65, defining within the s wall portions an elongated runway 67. Surface 62 contains a slot 60 extending longitudinally of guide structure means (not shown) drive conveyers 37. and 38 so that the veneer passes in a continuous flow through the apparatus. l r r Secured to transverse beam 13 above the clipper blade assembly is an air pressure valve 39 regulating the pressure fluid and exhaust connections to piston-cylinder device 27. Exhaust conduit 41 and pressure fluid conduit 42 provide the pressure and exhaust connections for valve 39. Pressure fluid conduit 42 is connected in a conventlonalnlanner to a source of fluid pressure (not shown).

Posltioned over the veneer sheet at the infeed side of the apparatus and engaging the veneer in its travel is a meter wheel 43 which may resemble a conventional bicycle wheel. Meter wheel 43 is secured to ashaft 44, shaft 44 being secured in turn through a universal 4-6 to a stub shaft 47. Stub shaft 47 is rotatably supported in a bracket 48 afiixed to the sides of A-frame member 11. Afiixed to the stub shaft is a sprocket which'drives a chain .49 extending upwardly and encircling a driven sprocket 50. Driven sprocket 5t), rotates a control shaft 51. By the mechanism described, rotation is imparted to control shaft Slat a rate determined by the rotation of meter wheel 43. Control shaft 51 drives a pair of control members in a control mechanism, indicated generally in Figs. 1 and 2, by the rectangular box 52.

Referring now more specifically to Figs. 3, 4, and 6, wherein the control mechanism is shown in detail, the control mechanism comprises a frame structure and a pair of

control units

53 and 54 secured to the frame structure 7 and arranged to' actuate sequentially air pressure valve 39. t The units are similar to one another, each having a control member movable from a rest or a base position to an activating or pulse energizing position. A control 61. Guide structure 61 is comprised of phenolic resinous material or other electrically insulating material. t Extending along bottom wall 64.along a substantial part of runway 67 is an electrical conductor strip 68. A rectangular contact block 69 is slidably mounted, within runway 67 for longitudinal movement along the runway. Secured tothe base of block 69 and slidable on strip 68 is an electric conductor 71, and electrically connected to COB-r ductor 71 and at the top of the block is'an electric contact strip 72.

. At'spaced intervals along and lying above the top of surface 62 and affixed to a pair of

rail portions

73 and 64 running longitudinally along surface 62 are plural pairs of bracket mounts indicated'at 76, 77, and 78. Rail por tions 73, 74 are constructed of the same material as guide structure 61. Each pair of bracket mounts supports op posite ends of an adjuster shaft 81. .Each of the adjuster shafts has affixed to its outer end aknob 32 enabling theshaft to be rotated manually. Athxed to an intermediate portion of each adjustershaft is a pinion gear 83.

Slidably' supported'on the top of planar surface 62 beneath each of the adjuster shafts is a block segment '84, also made of electrical insulating material. Each of the block segments carries affixed to its upper surface a rack segment 86 which engages a co-opcrating pinion gear 83. Block segments 84 are positionable longitudinally along guide structure61 by rotating the knob of each adjuster shaft and the pinion gear aifixed to the shaft.

i A screw 87 and clamping member 88 is provided to ad just the freedom of movement of each block segment within

rails

73 and 74.

Each of the block segments carries at its lower surface a contact strip 91 adapted to engage contact strip 72 of contact block 69 when the block is moved under the block segment. 5 i 1 An advancing meansor mechanism is provided for. moving contact block 69, which comprises the control member for each of the control units, from the position it occupies at the right of guide structure 61 in Fig. 3,

which is its base or rest position, to an activating or pulse generating position wherein the contact strip of the cork tact block contains one of the contact strips of block segments 84. Additional mechanism returns the contact block to its base position after the block has reached the pulse generating position.

As can beseen in Fig. 3, 4, and 6, each of the control units is provided with a chain and sprocket assembly d mounted to one side of the guide structure for theunitl Thus, extending longitudinally along the guide structure for control unit 53 is a chain 101 wrapped about and engaging at opposite ends a pair of

sprockets

102 and 103. Similarly, extending along beside the guide structure for control unit 54 is a chain 104 wrapped about and engaging at opposite ends a pair of

sprockets

106 and 107.

Sprockets

103, 107 are rotatably supported at one end of

control units

53, 54 by suitable shafts supported by a pair of

brackets

108 and 109. At the other end of the control units, sprocket 106 is rotatably sup ported on control shaft 51 discussed hereinbefore in the general description of the clipper apparatus. Sprocket 102 is rotatably supported on an intermediate shaft 111. Shafts 111 and 51 are connected for simultaneous rota- As can be seen with reference to sprocket 102 for upper control unit 53, friction clutch means are included between driving

sprockets

102, 106 and the shafts supporting these sprockets. Considering intermediate shaft 111, intermediate the ends of the shaft between the pair of brackets supporting the shaft is a clutch 115 having a driving clutch face 116 affixed to the shaft and a driven clutch face 117 secured to sprocket 102. A compression spring 118 and adjusting nuts 119 are included to enable the frictional engagement of the clutch faces to be adjusted as desired. A similar arrangement connects the drive from control shaft 51 to driving sprocket 106 for the lower control unit. In this manner,

chains

101 and 104 are constantly urged in a counterclockwise direction in Fig. 4 about their supporting sprocket by the rotation of meter wheel 43 in a counterclockwise direction in Fig. 2.

Secured to the frame structure for the control mechanism rearwardly of each control unit are a pair of

pistoncylinder devices

121 and 122. Each of the piston-cylinder devices has a piston rod 123 projecting outwardly therefrom and lying generally parallel to upper portions of the chain associated with each of the control units. Slidably mounted on the piston rod for each of the pistoncylinder devices is a return block 126. On the outer side of each piston rod and abutting each return block is a compression spring 127 seated on nut and washer assemblies 128.

With reference to Fig. 6, return block 126 for each control unit is affixed by means of a pin 129 to the chain associated with each control unit and the contact block for the unit. In this manner, the chain for each control unit, the contact block for the control unit, as well as the return block for the unit are secured together for simultaneous movement either to the left or to the right in Figs. 3 and 4, as will be discussed hereinbelow.

At the inner end of each cylinder of piston-

cylinder devices

121 and 122 is a conduit 131 connected through a suitable control valve to a high-pressure fluid source. At the other end of each of the cylinders of the pistoncylinder devices is a conduit 132 connected through a suitable control valve to a low-pressure fluid source. During operation of each of the control units, fluid is admitted into the low-pressure side of the piston-cylinder device so that the piston rod is moved outwardly from the piston-cylinder at a rate which is sufficient to release the return block mounted on the piston rod from engagement with compression spring 127. With reference to upper control unit 53, when this occurs, the return block together with the contact block and drive chain for the unit is free to move toward the left in Fig. 3 under the urging of sprocket 102 and chain 101. Movement in this direction continues until high-pressure fluid is admitted to the high-pressure side of piston-cylinder de- 'vice 121. The piston rod is then retracted inwardly in the piston-cylinder under a force sufiicient to override the frictional drive of drive gear 102. The contact block is' thus returned to its base or rest position by movement tion by drive sprockets 112 and 113 and a drive chain.

of the return block to a hold position adjacent the-end of the piston-cylinder device. The return block is held in this hold position by the piston rod until the exhaust of pressure fluid from the high-pressure side of the pistoncylinder and the admission of pressure fluid into the lowpressure side of the piston-cylinder at which time the whole operation repeats. Thus, the return block for each control unit acts as an overriding regulator means returning each contact block to its base position and releasably holding the contact block in its base position, upon movement of the regulator means to a 'hold position.

Mounted on the cylinder housing portion of pistoncylinder device 121 is a switch 133, and a similar switch 134 (illustrated in Fig. 5 is provided for the lower pistoncylinder device. The switches are conventional and are so mounted that return block 126 for each piston-cylinder device operates to close the switch contacts of the switch when the return block is in its hold position. These switches form a part of the control circuit to be de scribed.

-

Control units

53 and 54 are arranged in the control mechanism so that each operates sequentially, each con trolling one of the strokes of piston-cylinder device 27 operating the clipper blade. Interlockcontrol means operatively interconnect

control units

53 and 54 so that the contact block for one of the units is urged to the left in Fig. 3 by the drive chain for the unit, thereby to measure a delay interval between successive actuations of the clipper blade at the moment the clipper blade undergoes a cutting pass upon actuation by the other unit. The contact block for this other unit is returned to itsbase position by the piston-cylinder device associated with the unit after actuating the clipper blade to ready itself for measuring a subsequent delay interval. The delay interval measured by the first of the units is initiated when the other of the units actuates the clipper blade and extends between the time the contact block for the first of the units leaves its base position and the time it reaches one of the block segments. When the contact block for the first of the control units reaches a block segment, the contact block for the other of the control units is released and starts measuring off a delay interval. Thus, the delay interval which elapses between successive releases of the contact block for one of the control units is determined from the time the contact block reaches a pulse generating position and independently of its return to the base position.

The interlock control means for the mechanism of this invention is best illustrated in Fig. 5. The majority of the wiring, electrical elements, and control valves have been eliminated from the other figures in the drawings for the reason of clarity. It should be realized that the wiring and valve connections in Fig. 5 are present in the remaining figures in the drawings. The interlock control means has been described diagrammatically in Fig. 5 so as to permit a better understanding of the various functions of the parts.

Referring to Fig. 5, the meter wheel for the apparatus is indicated at 43. Intermediate and control shafts are indicated at 111 and 51, respectively.

Numbers

102 and 106 represent the driving sprockets rotatably mounted on the shafts and clutches -L and 115-U the friction clutches between these shafts and the driving sprockets for upper control unit 53 and lower control unit 54.

Numbers

101 and 104 represent the chains for each of the control units and 6 9U and 69L the contact blocks for the units.

As illustrated in Fig. 4, each of the control units has three block segments associated therewith. These block 7 The elongated electrical conductor strips running thelength of each guide structure for each control unit are indicated at 68.-U and 68 1.. Electrical conductor 68-U isconnected by a suitable electrical conductor to one of 8 the switch contacts of switch 134, the other of-the switch contacts of switch 134 being connected to one end of a solenoid 160. 68L is connected to one contact of switch 133, the other In a similar manner, electrical conductor contact of switch 133 beingconnected :to solenoid 160.

Solenoid 160, as well as the other solenoids discussed herein, are conventional solenoids having a movable armature which is spring biased to one extreme position so as to describe a to-and-fro movement when energized and tie-energized, respectively. vWith respect to solenoid 160, the other end of the solenoid is connected by anele'ctrical conductor to source conductors 152. From the above description, it will be apparent that movement of con.- tact blocks 69-U along its underlying conductor strip 63+U results in energizing solenoid 160 when switch 134 is closed and the contact block engages a block segment which is connected by one of the switches 146, 147, or

14-8 to line conductor 151. In a like manner, movement of contact block 69-L along conductor 68-L results in energizing solenoid 160 when switch 133 is closed and contact block 69-L engages a block segment which is.

by. switch 146, 147, or 1.48 to line conde-energizing solenoid 160 causes ratchet 163 to ipar- Every pair of partial revolutions of tially revolve. ratchet 163 presents in order a raised and a lowered portion of block 164 to a pivoted 'feeler 166. Feeler 166 is ganged to a switch point 167 adapted to engage selectively one of a pair of switch contacts 168 and 169.

Connected between switch contact 168 and source conductor 151 by means of a suitable electrical conductor is a clipper solenoid .171. Similarly, connected between switch contact 169 and source conductor 151 is a second clipper solenoid 172; Each of these solenoids is ganged to valve 39. controlling the delivery and exhaust of air pressure to piston-cylinder device 27. Valve 39 is conventional, accommodating selectively either the admission of air'pressure to one side of piston-cylinder 27 and a fluid exhaust for the other side of the piston-cylinder or the admission of air pressure to the other side of pistoncylinder' 27 and a fluid exhaust for the'first side of the piston-cylinder. i

' Connected by a conductor between switch contact 168 and source conductor 151 is a return solenoid 176-f0r piston-cylinder 122. Also connected to ,switch contact 168 and source conductor 151 is a release solenoid 177 for piston-cylinder 121.

Solenoids

176 and 177 are ganged to control valves an exhaust connection for theleft side of the piston.

,cylinder. Solenoid 182, when energized, provides an exhaust connection for the right side of piston-cylinder 122 and admits pressure fluid to thelett side of the pistoncylinder. I V

The operation of the above will now be described. The condition of the parts will be assumed to be as they are illustrated in Fig. 5, that is, switch' 147 is closed and switch point 167 is contacting switch contact 16 8. The contact block forv control unit 54 is moving under the urging of chain 104 to the left in Fig. 5'.

Solenoids

171, 176, and 177 are energized. In this condition of the parts, pressure fluid isbeing admitted to the right side of piston-cylinder 122 and the left side of piston-cylinder 121. The piston rod for" control unit 54 is advancing to V the left ahead of the contactblock and the drive chain carrying the block so that the contact block is free to move under the urging of chain 104. The contact block for upper control unit 53 is being held in its base position, solenoid 177 being energized so that the left side of piston-cylinder 121 is subjected to pressure fluid and 'the' right side of piston-cylinder 12.1 is opened to exhaust. 6 Since the return block for the upper control unit is in its hold position, switch 133 is closed.

Whencontad block 69-L for control unit 54 reaches block' segment 84-8, solenoidlt) is energized, causing a partial rotation of ratchet 163 and'movement of switch point 167 from contact 168 to contact 169. This results in a die-energizing

of'solenoids

171, 176 and 177 and an indicated at 178, 179, 183, and 184. These valves are conventional and present selectively either inlet or exhaust connections to the one side of the piston-cylinder device associated therewith. Solenoid 176, which is ganged to

valves

178 and 1 83 at each end of pistoncylinder 122, when energized, admits air under pressure to the right side of piston-cylinder 122 and exhausts pressure fluid from the left side of the piston-cylinder. Solenoid 177, when energized, admits air under pressure to the left side of piston-cylinder 121 and exhausts pres: sure fluid from the right side of the piston-cylinder.

' rolling this stroke of the piston. The control mechanism is flexible, permitting a variety of different lengths to be A similar set of

solenoids

181 and 182 are provided 7 between switch contact 169 and line conductor 151:."

Solenoid 181, when energized, admits fluid under .pres- 7 sure to the right side of pistonQcylindr 1'21 and provides energizing of solenoids 172,-181, and 182. Asa conse: quence, the pressure fluid and exhaust connections for piston-cylinder 27 are reversed so that the clipper blade undergoes a cutting pass by movement of the piston head within piston-cylinder 27 from one end of the piston-. cylinder to'the other. in addition, pressure fluid is admitted to the left and right sides of piston-

cylinders

122 and 121, respectively, while the other sides of the piston= cylinders are opened to exhaust.

This adjustment causes the pistonfor piston-cylinder 122 to return to its hold position thereby movingcontact block .69-L from block segment 84c so as to de-energize solenoid 168 and the. piston for piston-cylinder 121 to advance ahead of contactblock 69-U and chain 101. Contact block 69-U is free to move to the left under the urging of chain 101, and movement of the contact block for piston-cylinder 121 continues until the contact block engages block segment 84b. If contact block 69-L for the lower control unit has reached its base position, switch 134 will be closed so that when contact block 69-U engages block segment 84b, solenoid is energized and the connections for the various piston-cylinders are again reversed. v

It will be noted from the above that each stroke of piston-cylinder 27 operating the clipper blade for the mechanism is controlled by a separate control unit. Each control unit, in turn, may be finely and accurately adjusted. .Any unbalanced conditioncreated by the fact that the reciprocating motor mechanism 27 driving the clipper blade completes two cutting passesfor each complete reciprocation may be readily accommodated. If, for example, it is found that the clipper blade moves somewhat more slowly when the piston of piston-cylinder 27 in Fig. 5 moves toward the right than when it moves to the' left, the action of the piston-cylinder may be regu lated by proper adjustment of the block segment concut at will. I

Block segments 84a and 840 for contact block 69-U and block segments 84d and 84 for contact block 69.L

time interval between successive energizings of s enoid 160 is regulated by block segments 84a and 84d. Contact blocks 69-U and 69-L move a longer distance to engage these block segments than they do to engage block segments 84b and 842 so that when switch 146 is closed, pieces of veneer produced by the clipper are longer than those produced if switch 147 only is closed. On the other hand, if switch 143 only is closed and switches 146 and 147 are opened, block segments 84c and 84 control successive energizings of solenoid 160, and shorter pieces of veneer are produced by the trimmer.

Switches

146, 147, 148 thus constitute means for selecting selected ones of the block segments and thus selected ones of the pulse generating stations to place them in operating condition.

The contact blocks for the control units are returned to their base position at a fairly rapid speed which is somewhat faster than the rate of movement of the contact blocks away from their base position. This is to insure that each of the contact blocks is in its base position prior to the time it starts measuring ofi a delay interval. Preferably, therefore, a source of relatively high fluid pressure is employed to move the contact blocks to their base position.

Switches 133 and 134 are included to prevent a momentary energizing of coil 160 in the event the contact block which has just actuated the clipper blade happens to travel beyond the block segment which it engaged to bring about the actuation. For instance, if contact block 69L should travel slightly beyond block segment 842, on returning to its base position, it would again engage block segment 842. This would disrupt the timing of the mechanism. Switch 133 is opened at the moment contact block 69-U for the upper unit leaves its base position and, in this manner, opens the line between solenoid 160 and conductor 68-L. by opening the line, tripping of the mechanism by the return of contact block 69-L is prevented.

A manually operable switch 165 is included to connect solenoid 160 to source

conductors

151 and 152 when it is desired to have random cuts.

it should be noted that by providing two control units, operating sequentially, the contact blocks for each unit have a chance to return to their base position before measuring off a delay interval. Many systems employing a movable control member require that the control member both return to a base position and then advance from this position in measuring a delay interval. Such systems are extremely hard to regulate, and, because of the inertias involved, the timing interval is subject to considerable variations.

While there has been described an embodiment of this invention, it should be understood that modifications and variations are possible without departing from the inventive concept of this invention, and itis desired to cover all modifications and variations which would be apparent to one skilled in the art and that come within the scope of the appended claims.

It is claimed and desired to secure by Letters Patent:

1. In clipper apparatus, said apparatus having a clipper blade for the cutting of material, power means for imparting movement to the blade, and means for transporting material through the apparatus past the clipper blade, the improvement comprising control means operatively connected to the power means for causing periodic actuation of the power means and thus periodicrnovement of the blade, said control means comprising a frame, a control member mounted on said frame for movement between a base and a pulse generating position, said control member in the latter position producing a pulse for causing actuation of the power means, releasable regulator means for said control member for returning the control member from said pulse generating position to said base position and for releasably holding said control member in said base position, advancing means for said control member for moving the control member from said base to said pulse generating position at a speed related to the speed of material transported through the apparatus upon release of said control'member by said regulator means, and means for periodically releasing said regulator means to enable movement of the control member by said advancing means after a delay interval determined from the time said control member reaches said pulse generating position and independently of the time of its return to its base position.

2. In clipper apparatus, said apparatus having a clipper blade for the cutting of material, power means for imparting movement to the blade, and means for transporting material through the apparatus past the clipper blade, the improvement comprising control means oper atively connected to the power means for causing periodic actuation of the power means and thus periodic movement of the blade, said control means comprising a frame, a control member mounted on said frame for movement between a base and a pulse generating position, said control member in the latter position producing a pulse for causing actuation of the power means, releasable regulator means for said control member for returning the control member from said pulse generating position to said base position and for releasably holding said control member in said base position, advancing means for said control member for moving said control member from said base to said pulse generating position at a speed related to the speed of material transported through the apparatus upon release of said control mem' her by said regulator means, and means for periodically releasing the regulator means to enable movement of the control member by said advancing means after a delay interval determined from the time the control member reaches said pulse generating position and independentiy of the time of its return to said base position, the means for periodically releasing the regulator means including means responsive to the speed of material transported through the apparatus for determining the length of said delay interval.

3. In a veneer clipper, saidv veneer clipper having a clipper blade for cutting veneer, power means for int parting movement to the blade, and means for transporting veneer through the apparatus past the clipper blade, the improvement comprising control means operatively connected to the power means for causing periodic actuation of the power means and thus periodic movement of the blade, said control means comprising a frame, a control member mounted on said frame for movement between a base and a pulse generating posi tion, said control member in the latter position producmg a pulse for causing actuation of the power means, regulator means for said control member for returning said control member from said pulse generating position to said base position and for releasably holding said control member in said base position, a meter wheel rotatably mounted adjacent the path of veneer transported through the apparatus for engaging such veneer, advancing means for said control member for moving sa1d control member from said base to said pulse generating position, said advancing means being connected to said meter wheel for movement at a speed related to the rotation of said meter wheel, and means for periodically releasing said regulator means after a delay interval determined from the time the control member reaches said pulse generating position and independently of the time of its return to said base position, said means for periodically releasing said regulator means including means connected to said meter wheel and movable at a speed related thereto for determining the length of said delay interval.

4. In veneer clipper apparatus, said apparatus having a clipper blade for cutting veneer, power means for im parting movement to the blade, and means for transport ing veneer through theapparatus past the clipper blade, the improvement comprising control means operatively connected to the power means for causing periodic actua in a path from a base position a series of pulse getter- 'ating stations arranged along the path of movement of said control member .for contact with said control member, means "for placing in operating condition one of said stations, said control member on moving over a pulse generating station which has been placed in operating condition producing a pulse for causing actuation of the power means, regulator means for said control member for returning the control member from a pulse generating station to said base position and for releasably holding the control member in said base position, advancing, means for the control member for moving the control member at a speed related to the transport speed of veneer through the. apparatus from saidbase position into contact with a pulse generating station which has previously been placed in operating condition, and means for periodically releasing said regulator means to enable movement of said control member: by saidiadvanoing' means after a delay interval determined from the time the control member reaches a pulse generating station 7 and independently of the time of its return to said base position.

5. In veneer clipper apparatus, saidlapparatus havinga; clipper blade for cutting veneer, power means forim parting movement to the blade, and means for transporting veneer through the apparatus past the clipper blade, the improvement comprising control means operatively connected to the power means for causing periodic actuation of the power means and thus periodic move ment of the blade, said control means comprising a frame, a control member mounted in said frame for movement between a base and a pulse generating position, said control member in the latter position producing blade; said control means comprising a series of control units, each connected to the power means for actuating the power means; each of said control units having a frame portion, a control member mounted .for movement on the frame portion between a base and a pulsegenerao ing position, advancing means for moving said control member from said base to its pulse generating position at a speed related to the speed of veneer transported through the apparatus, and return means for returning said control member to said base position and holding the control member in its base position after movement of 1 the control member to its pulse generating position; and

circuit means operatively interconnecting said control units for causing the control member of one of the control units to be held in its base position by the return means of the unit until the control member. for another control unit reaches its pulse generating position, and for causing the advancing means for said one of said control units to move the control member of the unit toward its pulse generating position when the control :member for said other control unit reaches its pulse generating position; said control units producing actuation of, the power means upon a control member reaching a pulsegenerating position.

.9, In a veneer clipper; said clipper having a clipper blade for cutting veneer, power means for imparting movement to the blade, and means for transporting veneer through the clipper past the clipper blade; the, im-

' provement comprising control means operatively connected to the power means for causing periodic actuation of the power -means and thus periodic movement of the blade; said control means comprising a pair of con- 'trol units, each connected to the power means for actuata pulse for causing actuation of the power means, a:

meter wheel rotatably mounted in the path of veneer transported through the clipper apparatus for engaging such veneer, means connecting said meter wheel to said control member for causing said meter wheel constantly to urge said control member 'towa'rds said pulse gener ating position at a rate of speed determined by the rotation of said meter wheel, overriding, power driven regulator means-for the control member for periodically returning; the control member to its base position, said regulator means being mounted for movement between hold and release positions and positioned and arranged to return said control member to said base position upon movement thereof, towards its hold position and to ac-I commodate movement of the control member by said meter wheel to said pulse generating position upon movement of the regulator means to its release position, and

means periodically for placing said-regulator means in its release position.

6. Theapparatus of claim 5 wherein said regulator means comprises an expansible fluid motor operable'on actuation of the motor to return thecontrol member, to H8 base position against the constant urging of said meter wheel. t

7. The apparatus of claim-6 wherein said expansible fluid motor comprises a double acting piston-cylinder having a high and alow pressure side, and whereinsaid piston-cylinder is arranged so that expansion of the'high pressure side causes movement of said regulator means ing the power means; each of the control units having a frame portion, a control member mountedon the frame portion for movement between a base and a pulse generating position, advancing means for moving the control member from its base to its pulse generating position at a speed related to the speed of veneer transported through the apparatus, and return means for returning the control 7 member to its base position and holding the controlmember in its base position after movement of the control ,7

member to its pulse generatingposition; and control unit interlock means for causing the control member of one control unit to be held in its base position by the return means of the unit until the control member'of the other control unit reaches its pulse generating position, andfor causing the advancing means of the one control unit to move the control member for the unit towards 'its pulse generating position when the control member for the other control unit; reaches its pulse, generating position; said control units producing actuation of the power means upon a' control member reaching a pulse generating position: v a p 10;, Ina veneer clipper; said veneer clipper having a clipper'blade for cutting veneer, power means for imparting movement to the blade, and means for transporting veneer through the clipper past the clipper blade; the improvement comprising control means operatively connected to the power means for causing periodic actuation t of the power means and thus periodic movement of the blade; said control means comprising a pair of control units, each connected to the power means for actuating the power means; each of the control units having a ,frameportion, a control member mounted on the frame portion for movement between a base and a pulse gen: erating position, advancing means for moving the control member from its base to its pulse generating position at 1 a speed related to the speed of veneer transported through the apparatus, and overriding, power-driven regulator means mounted for reciprocal movement on the frame portion between hold and release position for returning thecontrol member to its base position upon movement ot'the regulator means toward its hold position and for releasing the control member to accommodate move- 13 ment of the control member to its pulse generating position upon movement of the regulator means to its release position; and control unit interlock means interconnecting the control units for regulating the sequence of operation of said control units; said interlock means connect ing the regulator means for the control units so that the control member for one control unit is maintained in its base position by the regulator means for the unit until the control member for the other control unit reaches its pulse generating position, the regulator means for the one control unit moving to a release position upon the control member for the other unit reaching a pulse generating position thus to enable the advancing means for said one control unit to move the control member for the unit towards its pulse generating position; said control units being connected to the power means to produce actuation of the power means upon a control member reaching a pulse generating position.

11. In a veneer clipper, the combination of a clipper frame, means supported on the frame for transporting veneer in a path through the clipper, a die member mounted adjacent the path of travel of veneer tln'ough the clipper, a clipper blade for cutting veneer mounted adjacent said die member and movable during one cutting pass of the blade toward and then away from the die member, a two-stroke, reciprocating power means connected to said clipper blade for imparting movement to the blade, each stroke of the reciprocating power means 14 V r producing one cutting pass of the clipper blade, and control means operatively connected to the power means for controlling the operation of the power means, said control means comprising a pair of control units, means connecting the control units to said power means for causing one of the control units to actuate one stroke of the power means and the other of the-control units to actuate the other stroke of the power means, and means interconnecting the control units for causing the two to operate in sequence, each of the control units having time delay means responsive to the speed of transport of veneer through the clipper, the time delay means of each control unit being constructed to produce actuation of the power means by the control unit after a delay interval determined from the time the power means is actuated by the other of the control units,

References Cited in the file of this patent UNITED STATES PATENTS