US3463295A

US3463295A - Apparatus for overlapping scarfed veneer sheets

Info

Publication number: US3463295A
Application number: US657099A
Authority: US
Inventors: Norman Thomas Shelton
Original assignee: Potlatch Forests Inc
Current assignee: Potlatch Forests Inc
Priority date: 1967-07-31
Filing date: 1967-07-31
Publication date: 1969-08-26
Anticipated expiration: 1986-08-26

Description

6, 1969 N. T. SHELTON 3,463,295

APPARATUS FOR OVERLAPPING SCARFED VENEER SHEETS Filed July 31, 1967 4 Sheets-Sheet 1 INVENTOR. NOR/MN TIM/1A6 dl/[LTON BY wlm ikpm Aug. 26, 1969 N. T. SHELTON APPARATUS FOR OVERLAFPING SCARFED VENEER SHEETS Filed July C51, 1967 4 Sheets-Sheet 2 INVENTOR. NOR NAN THOHIJ 5!- TON Aug. 26, 1969 N. T. SHELTON 3,463,295

PARATUS FOR OVERLAPT'ING SCARY'ED VENEER SHEETS I 4 Sheets-Sheet Filed July 31, 1967 II'- IIITIIYIIIIIIIIIIXI {-nf.

INVENTOR. NOR/1AM THO/1A6 III/ELTON Aug. 26, 1969 N. T. SHELTON 3,463,295

APPARATUS FOR OVERLAPPTNG SCARF'EI) VENEER SHEETS 4 Sheets-Sheet -1 Filed July 31, 1967 INVENTOR. NORMAN THOMAS JIIGLTGN United States Patent U.S. Cl. 198--35 16 Claims ABSTRACT OF THE DISCLOSURE The disclosure describes an assembly apparatus for overlapping scarfed veneer sheets to form a continuous veneer strip. The apparatus has an indexing device and an alignment and overlapping device. The alignment and overlapping device has a stationary platform for receiving the sheets. Pusher members are mounted on conveyor chains for engaging the trailing ends of the sheets. The pusher members are evenly spaced along the chains at distances less than the length of the sheets so that each sheet overlaps the preceding sheets. A stripper plate is mounted across the front of the alignment and overlapping device for stripping the sheets from the pusher members. Support members are mounted to the chains behind the pusher members for supporting the forward end of the sheets. The indexing device has transfer members reciprocally mounted for movement perpendicular to the alignment and overlapping device. The transfer members are timed to feed a sheet onto the alignment and overlapping device immediately ahead of the pusher members.

BACKGROUND AND OBJECT OF INVENTION This invention relates to an assembly apparatus for making a continuous veneer strip from veneer sheets and more particularly to an apparatus for indexing and overlapping scarf veneer sheets to form a continuous veneer strip.

Plywood veneer is very thin and is generally produced in sheets having lengths slightly greater than eight feet and widths slightly greater than four feet. The strength properties of veneer is substantially directional and is dependent upon the direction of the wood grain. In one direction, veneer is quite brittle and will readily break when forces are exerted tending to bend the veneer parallel to the grain. In the other direction veneer is quite flexible and exhibits substantial resistance to bending forces tending to bend the veneer transverse to the grain. Because of these physical characteristics of veneer, special care must be used in assembling the veneer sheets into a continuous veneer strip.

Normally in the formation of a continuous veneer strip the ends of the veneer sheets are first trimmed and beveled to facilitate the joining of the sheets. The beveling process is generally referred to in the industry as scarfing, in which one end of each sheet is cut with a beveled or scarfed surface facing down and the other end of the sheet is cut with a scarfed surface facing up. When the ends of the sheets have been scarfed, the end edges are thin and are highly susceptible to damage.

Generally, heretofore veneer strips were produced by placing one sheet stationary on a flat surface with the trailing edge facing upward in a joint press. Adhesive was added to the trailing scarfed end. A second sheet was then manually aligned on the flat surface with its forward scarfed end overlapping the trailing scarfed end of the first sheet under the press. The press was then operated to cure the scarfed ends together to form a joint. Sometimes a third sheet was joined in a like manner to the second sheet. However, it became particularly cumbersome to make a strip more than two or three sheets long because of the problems encountered in incrementally moving the strip forward, stopping the strip, and aligning the trailing edge of the strip properly so that another sheet could be added. Consequently, it was impractical to form a continuous veneer strip of substantial length.

Apparatus has been developed to somewhat automate the above described process. The apparatus first stationarily positions the preceding sheet with its trailing end against an alignment member. The succeeding sheet is then fed forward until the forward end of the succeeding sheet abuts against stop members that are positioned over the trailing edge of the preceding sheet so that the forward end of the succeeding sheet overlaps the trailing end of the preceding sheet by the desired distance. Both sheets were then independently gripped and in unison moved forward to a press. Each time a sheet is added to a strip the problem of moving, stopping and aligning the trailing end of the strip becomes more diflicult. As a practical matter it is uneconomical to make a strip more than a few sheets using this apparatus.

It should be appreciated that a few cents savings in the manufacturing of each increment of plywood veneer means the difference between commercially usable equipment and research equipment which is abandoned after testing. For this reason it is extremely important that the equipment be economical to construct and efficient and reliable in operation for making veneer strips.

One of the principal objects of this invention is to provide an apparatus for assembling a continuous veneer strip from veneer sheets that is economical to manufacture, simple in construction, and above all efiicient and reliable in operation.

An additional object of this invention is to provide an apparatus for assembling a continuous veneer strip from veneer sheets which alleviates the necessity of stopping the strip as it is being formed.

A further object of this invention pertains to the capability of accurately aligning the sheets in an overlapping manner by reference to only the trailing edges of the sheets.

An additional object of this invention is to accurately index and position a sheet along a selected path in an efiicient and reliable manner.

A further object of my invention is to provide an apparatus that pushes the trailing end of the sheets Without damaging the trailing thin edge of the sheets.

An additional object of this invention is to provide an efiicient and simple apparatus for indexing veneer sheets utilizing the directional strength properties of the veneer.

An additional object of my invention is to provide an apparatus that requires a minimum of floor space for operation in making a continuous veneer strip.

SUMMARY OF THE INVENTION This invention concerns an assembly apparatus for making a continuous veneer strip from veneer sheets having uniform lengths and scarfed ends. The apparatus comprises a plurality of evenly spaced pusher members that are movably mounted on a frame for movement along a selected path to move against the trailing scarfed ends of the sheets. The interval between the pusher members is less than the uniform length of the sheets by a prescribed distance. A drive system continuously moves the pusher members at a selected speed. More particularly the apparatus further includes support members that are mounted for movement behind each of the pusher members to support the forward end of the sheets spaced from the pusher members. A stripper plate is mounted to the frame in the path of the forward end of the sheets for receiving the sheets and stripping the trailing end of the sheets from the pusher members and into abutment with the forward end of the succeeding sheets as the sheet moves forward on the frame. An indexing device is mounted adjacent the selected path for indexing the sheets into the selected path at a rate related to the speed of the pusher members and timed to position the trailing edges of the sheets in front of the moving pusher members.

BRIEF DESCRIPTION OF THE DRAWINGS A preferred embodiment of this invention is illustrated in the accompanying drawings, in which:

FIG. 1 is a plan view of the assembling apparatus embodying the principal features of this invention;

FIG. 2 is a side elevation view of the assembling apparatus;

FIG. 3 is a cross sectional view of the assembling apparatus as taken on line 3--3 in FIG. 1;

FIG. 4 is a perspective schematic view showing a scarfed veneer sheet being indexed onto an overlapping apparatus; and

FIG. 5 is a perspective schematic view showing a veneer sheet with its leading end overlapping the trailing end of a preceding sheet on the overlapping apparatus.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to the drawings in more detail there is shown in FIG. 1 an assembling apparatus for forming a continuous veneer strip having an indexing device 210 and an alignment and overlapping device 211.

The indexing device comprises a frame 96 (FIG. 3) that is aligned along a selected path X. Tubular frame members 97 are mounted on the base frame 96 transverse to the selected path. The frame also includes longitudinal frame channels 113 that are evenly spaced for supporting the veneer sheets.

Fluid operated piston-

cylinder actuators

215 and 216 are horizontally mounted to the two outermost longitudinal channels 113 by bracket 217. The

actuators

215 and 216 are mounted slightly below the top of the longitudinal channels 113 and slightly set back from the forward ends of the longitudinal channels 113.

Piston rods

218 and 219 are slidably mounted in the

actuators

215 and 216 respectively for reciprocating movement forward of the frame 96. The

rods

218 and 219 may be referred to as transfer members. Vertical plates 221 are mounted on the rear ends of the longitudinal channels 113 and serve as stripper plates for engaging the trailing side of the sheet to strip the sheets from the

piston rods

218 and 219.

Also mounted on the frame 96 is a scarfing conveyor system 102, shown in phantom, that grips the ends of cross-positioned sheets of veneer. The scarfing conveyor 102 moves the sheets crosswise along the selected path X past trim saws 114 and 115 that trim the end of the sheets to form uniform length sheets having parallel edges. The scarfing conveyor also moves the sheets past scarfing saws 122 and 123 that bevel the ends of the sheets. The scarfing saws 122 and 123 are so arranged that the scarfed surface of one faces upward. The other end has a beveled surface formed thereon that faces downward. Generally the scarfed ends may have a seven to one slope so that a sheet of veneer one-sixth of an inch thick has 1% inches of scarfed ends. The scarfing conveyor 102 also moves the sheets past a glue applicator 127 that applies glue to the upwardly facing end surface of the sheets. The trim saws, the scarfing saws and the glue applicator are not a part of this invention.

Drive rollers 222 (FIG. 3) mounted on the rear end of the support members 113 receive the sheets from the scarfing conveyor 102 and move the sheets onto the

extended piston rods

218 and 219. Each of the drive rollers 222 are driven by a chain 224. The chains 224 are 4 moved by a shaft 106 that drives the lower section of the scarfing conveyor 102.

Pressure rollers 223 are rotatably mounted immediately above the drive rollers 222 to maintain the sheets in contact with the drive rollers 222.

When the

actuators

215 and 216 are actuated the

rods

218 and 219 are retracted to move the rear side of the sheet against the plates 221 to strip the sheets from the

piston rods

218 and 219. The sheets then descend onto the alignment and overlapping device 211.

The alignment and overlapping device 211 comprises a base frame 227 that is aligned along a selected path Y that is perpendicular to the selected path X. The base frame 227 includes an elongated platform 228 alinged along the selected path Y for supporting the central portion of the sheets as they are released from the indexing device 210. The elongated platform 228 is positioned so that it has a slight forward slope. Longitudinal channel irons or

chain races

230 and 231 are mounted to the sides of the platform 228 parallel with the platform 228 but slightly below the level of the platform so that they do not support the released sheets. Side rails 232 and 233 are mounted to the frame on the outside of the

longitudinal channels

230 and 231 to support the sides of the sheets as they are released. The upper surface of the side rails 232 and 233 are in the same plane as the upper surface of the platform 228. Like the platform 228, the side rails 232 and 233 have a similar forward slope.

An endless conveyor system is mounted on the frame 227 for moving the released sheets endwise along the selected path Y. The endless conveyor includes two

parallel conveyor chains

234 and 235 that are mounted between the platform 228 and the side rails 232 and 233 respectively with the upper flights thereof slidably supported on the

longitudinal channels

230 and 231. The

endless conveyor chains

234 and 235 are mounted between drive sprockets 236 that are fixed to a drive shaft 237 and idler sprockets 238 that are fixed to an idler shaft 240. The drive shaft 237 is mounted in bearing blocks 241 that are secured to the base frame 227. The idler shaft 240 is rotatably supported in bearing blocks 242 that are secured to the base frame 227. The upper flight of the conveyor is also sloping forward parallel to the platform 228.

Pusher members 244 are mounted to the chains 234 at uniform intervals. The distance between the intervals is less than the length of the sheets by a prescribed distance D. The distance D is slightly greater than the width of one of the scarfed surfaces. For some applications, D is set close to 1% inches. The pusher members 244 include brackets or lugs 245 that are secured to the

chains

234 and 235. Bars 246 are supported on top of the brackets 245 and extend transversely between the

chains

234 and 235 for structural rigidity. As the pusher members move to the upper flight of the conveyor, the lugs 245 slide over the

races

230 and 231 for engaging the trailing end of the sheets to push the sheets forward along the selected path Y. The lugs 245, when engaging the trailing end of the sheets, aligns the trailing edge of the sheets transverse with the Y path.

Support members 247 are mounted to the

chains

234 and 235 immediately behind the pusher members 244 for supporting the forward end of the sheets above the pusher members 244 and overlapping the trailing end of the preceding sheet. The support member 247 has a sufficient height to support the forward end of the sheets so that the sheets remain substantially horizontal on the alignment and overlapping device as they move along the selected path Y in a slight descending manner because of the slope of the apparatus (FIG. 2). Each of the support members 247 includes brackets or lugs 2.48 that are attached to the links of the chain. Each support member 247 also includes a bar 250 that extends between the

chains

234 and 235 for supporting the forward end of the sheets.

A stripper plate 252 is mounted transversely across the front of the frame 227 forward of the drive shaft 237.

The stripper plate 252 is positioned on the frame 227 spaced from the drive shaft 237 a suflicient distance to permit the support members 247 to round the forward end of the conveyor flight without engaging the stripper plate 252.

A lateral or transverse positioner 255 is mounted adjacent the base frame 227 parallel to the selected path Y for centering the sheets on the apparatus 211. The lateral positioner 255 includes shoes 256 that are secured to the floor (FIG. 3). Uprights 257 are pivotally mounted to the shoes 256 for pivotal movement to and from the selected path Y. A cross braces 258 extends between the uprights 257 to provide structural rigidity. Face plates 260 are mounted to the upper portion of the uprights 257 for engaging the sides of the sheets on the platform 228. A fluid operated piston-cylinder actuator 261 is connected through a bracket 262 to the base frame 227. Piston rod 263 extends toward the lateral positioner 255 and is connected to one of the uprights 257 by a bracket 264.

A limit switch 265 (FIG. 1) is adjustably mounted on the base frame 227 and is actuated by the pusher members 244 as the pusher members 244 approach the upper flight of the conveyor. The limit switch 265 actuates a solenoid valve that controls the actuators 2.15 and 216. A limit switch 267 is mounted on the frame 227 forward of the limit switch 265 and is actuated by the pusher members 244 for operating the transverse positioner 255.

The endless conveyor is driven by a rotating system drive shaft 46 (FIG. 3). The drive shaft of the right angle gear unit 269 moves a drive chain 270 that extends to a sprocket 271 affixed to the drive shaft 237. The indexing device 210 is timed with the position of the pusher members 244 so that a sheet is indexed onto the alignment and overlapping device 211 as a pusher member 244 is approaching the upper flight of the conveyor.

Initially the

piston rods

218 and 219 are extended to receive a sheet 20 from the scarfing conveyor. When a pusher member 244 rounds the idler shaft 240 and approaches the upper conveyor flight it actuates the limit switch 265. The actuation of the limit switch 265 causes the piston rods to retract the

rods

218 and 219 to move the sheet against the stops 221 to strip the sheet from the

piston rods

218 and 219. The sheet descends onto the elongated platform 228 and

side rails

232 and 233 with the trailing scarfed end of the sheet forward of the pusher member 244 and the forward scarfed end supported on the preceding support member 247. As the pusher member 244 continues to move, it engages and actuates the limit switch 267 to operate the actuator 261 to pivot the lateral positioner against the side of the sheet to laterally align the sheet on the alignment and overlapping device. The pusher member 244 then moves against the trailing end of the sheet to move the sheet forward at the selected speed. When the pusher member 244 engages the trailing edge of the sheet, the forward end is supported upon the preceding support members 247 with the forward edge projecting forward of the preceding pusher member 244 and overlapping the trailing end of the preceding sheet (FIG. 5). As the sheet approaches the forward end of the frame 227 it engages and slides over the stripper bar 252. The forward end of the sheet then moves onto a conveying system that is adjacent to the alignment and overlapping device 211 to continue moving the sheet. When the suceeding pusher member 244 rounds the idler shaft 240 and approaches the upper conveyor flight, it actuates the limit switch 265 to index a second sheet onto the platform 228.

The second sheet has its forward end supported upon a support member 247 and overlaps the trailing edge of the first sheet. The second sheet remains stationary upon the elongated platform 228 until the succeeding pusher bar 244 moves against the trailing end of the second sheet. When a pusher member 244 moves against the trailing end of the second sheet, the forward end of the second sheet is overlapping the trailing end of the first sheet by the prescribed distance D. At this point both sheets are moving forward at the same rate. Immediately thereafter the trailing end of the first sheet approaches the stripper plate 258 which causes its trailing end to move upwardly and into abutting engagement with the forward scarfed end of the second sheet. At this point a continuous strip is formed in which the forward scarfed end of the second sheet is in overlapping abutment with the trailing scarfed end of the first sheet. The forward end of the second sheet then moves over the stripper plate 252 and onto the adjacent conveying system maintaining the prescribed overlapping engagement. A pressing apparatus may be located down stream that moves along with the moving strip to cure the adhesive between the abutting scarfed ends.

Additional sheets are added to the strip in the manner to form a continuous strip of any desired length. It should be particularly noted that there is no stopping and starting of the strip to add additional sheets.

Although this embodiment describes an indexing device 210 that moves the sheet crosswise in a selected path X over the selected path Y and then lowers the sheet into the selected path Y, other arrangements may be readily devised. For instance, it is within the contemplation of this invention that the sheets may be fed longitudinally from the rear of the alignment and overlapping device 211 and into the elongated platform 228.

It is understood that the above described preferred embodiment is simply illustrative of the principles of this invention. Numerous other embodiments may be readily devised by those skilled in the art and the following claims are intended to define the invention.

What is claimed is:

1. In an assembly apparatus for forming a continuous veneer strip from veneer sheets having uniform lengths and parallel scarfed ends that are positioned lengthwise on the apparatus, said apparatus comprising:

(a) a frame positioned longitudinally along a selected path for receiving the sheets;

(b) a plurality of pusher members that are movably mounted on the frame for movement along the selected path at uniform intervals to move against the trailing scarfed end of the sheets, each of said intervals being less than the length of each sheet by a prescribed distances; and

(c) a drive means operably connected to the pusher members for continuously moving the members along the selected path at a preset speed so that"the forward scarfed end of each sheet overlaps the preceding sheet by the prescribed distance.

2. The apparatus as defined in claim 1 further comprising an endless conveyor movably mounted on the frame for movement at the preset speed along the selected path, and wherein the pusher members are mounted on the conveyor at the spaced intervals.

3. The apparatus as defined in claim 2 further comprising a stripper plate transversely mounted across the front of the frame for stripping the sheets from the pusher bar as the trailing end approaches the front of the frame.

4. The apparatus as defined in claim 3 further comprising support members attached to the endless conveyor behind the pusher members for supporting the forward end of the sheets vertically spaced from the pusher members and above the stripper plate.

5 The apparatus as defined in claim 1 further comprismg a lateral positioner for moving against one side of the sheets to laterally position the sheets on the frame.

6. The apparatus as defined in claim 5 wherein the lateral positioner is mounted adjacent one side of the apparatus frame and parallel to the selected path and comprises a movably mounted upright, a face plate mounted on the upright for movement against the sheets, and an actuator for moving the upright towards the selected path in timed relation with the position of the pusher members to laterally align the sheets on the frame.

7. The apparatus as defined in claim 4 wherein the frame comprises an elongated platform for supporting the sheets, and side rails spaced from the platform for supporting the sides of the sheets, and wherein further the endless conveyor comprises two parallel endless conveyor chains located between the platform and the side rails.

8. The apparatus as defined in claim 1 further comprising an indexing device for positioning the sheets lengthwise on the frame and a control means responsive to the location of the pusher members for operating the indexing device to position the sheets in front of the moving pusher members so that the forward ends of each sheet overlap the trailing end of the preceding sheet.

9. The apparatus as defined in claim 8 wherein the control means operate the indexing device to position a sheet on the conveyor immediately forward of a pusher member so that the pusher member moves against the trailing end of the sheet to space the sheet along the selected path.

10. The apparatus as defined in claim 7 wherein the platform, the side rails and the upper flights of the conveyor chains slope forward for maintaining the sheets substantially horizontal as they are moved along the selected path.

11. An apparatus for forming a continuous veneer strip from veneer sheets having uniform lengths and scarfed ends, said apparatus comprising:

(a) alignment and overlapping device having a conveyor aligned along a selected path for moving the sheets at a selected speed;

(b) transfer members that are reciprocally mounted for supporting and indexing the sheets over the selected path;

() stripping means aligned parallel to the selected path and adjacent the conveyor for stripping the sheets from the transfer members when the transfer members are retracted to release the sheets onto the conveyor;

(d) drive means for reciprocating the transfer members;

(e) control means responsive to the length of the sheets and the speed of the conveyor for operating the drive means to retract the transfer members to release the sheets so that the forward end of each sheet overlaps the trailing end of the preceding sheet by a prescribed distance.

12. The apparatus as defined in claim 11 wherein the transfer members comprise piston rods that are slidably mounted in spaced fluid operated actuators that are aligned perpendicular to the selected path.

13. The apparatus as defined in claim 12 wherein the stripping means comprises back stops that are positioned adjacent to and forward of the piston cylinders to strip the sheets from the piston rods as the rods are retracted.

14. The apparatus as defined in claim 11 wherein the alignment and overlapping device further includes:

(a) a stationary elongated platform for receiving the sheets;

(b) movable pusher bars equally spaced along the selected path at a distance less than the length of each sheet for engaging the trailing ends of the sheets;

(c) a second drive means for moving the chains at the preselected speed.

15. The apparatus as defined in claim 14 wherein the transfer members are mounted adjacent and transverse to the elongated platform for laterally indexing the sheets over the platform and wherein the stripping means includes backstops that are mounted adjacent and parallel to the elongated platform.

16. An apparatus for forming a continuous veneer strip from rectangular veneer sheets having uniform length and scarfed end edges that are supplied crosswise from a scarfing conveyor, said apparatus comprising:

(a) parallel spaced fluid operated actuators mounted immediately below and aligned with the scarfiing machine conveyor, said cylinders having piston rods that are slidably mounted therein for extending forward of the scarfing conveyor to successively receive the sheets and for transferring the sheets forward;

(b) a plurality of backstop members having faces that are aligned perpendicular to and slightly forward of a pneumatic cylinder for stripping the sheets from the piston rods when the sheets are retracted to release sheets; and

(c) an overlapping device positioned adjacent to and perpendicular to the pneumatic cylinder for receiving the released sheets, said overlapping device comprising:

(1) a frame;

(2) a stationary elongated platform mounted to the frame perpendicular to and below the line of travel of the piston rods for receiving the sheets;

(3) a pair of endless conveyor chains movably mounted on the frame straddling the elongated platform;

(4) a plurality of pusher bars transversely mounted to the chains for movement therewith, said bars being equally spaced along the chains at a distance slightly less than the length of the sheets for moving against the trailing scarfed end edges of the sheets;

(5) support members mounted to the chains behind the pusher bar for supporting the front end of the sheets;

(6) a drive means for moving the chains at a preselected speed;

(7) control means responsive to the location of the pusher members for operating the actuators to release the sheets in front of the pusher members so that the forward scarfed end of each sheet falls on one of the support members and overlies the preceding pusher bar that is engaging the trailing scarfed end edge of the preceding sheet so that the sheets overlap;

(8) a stationary stripper bar mounted transversely across the froward end of the platform immediately above the path of the pusher bars and in the path of the forward edge of the sheets for stripping the trailing edge of the sheet from the pusher bar and into engagement with the forward overlapping scarfed end of the succeeding sheet to form a continuous veneer sheet.

References Cited UNITED STATES PATENTS 2,198,036 4/1940 Isted 198-35 X 2,571,840 10/1951 Curlee 19835 X EDWARD A. SROKA, Primary Examiner US. Cl. X.R.