US3613859A

US3613859A - Indexing crossband veneer for automatic plywood layup equipment

Info

Publication number: US3613859A
Application number: US814770A
Authority: US
Inventors: Harold Keller; Patrick J Young
Original assignee: Potlatch Forests Inc
Current assignee: Potlatch Forests Inc
Priority date: 1969-04-09
Filing date: 1969-04-09
Publication date: 1971-10-19
Anticipated expiration: 1988-10-19

Abstract

An indexing mechanism is disclosed for intermittently feeding crossband veneer sheets to a plywood layup station. The indexing mechanism includes a vacuum feeder for successively conveying crossband veneer sheets to a stop means. The stop means includes a cylinder horizontally mounted transverse to the direction of travel with a flange thereon normally extending into the path of the sheets. The cylinder is rotated by a intermittent drive to intermittently feed the crossband to the plywood layup station with considerable precision.

Description

United States Patent Harold Keller;

Patrick J. Young, both of Lewiston, Idaho 814,770

Apr. 9, 1969 Oct. 19, I97 1 Potlatch Forests, Inc.

Lewiston, Idaho Inventors App]. No. Filed Patented Assignee INDE I IINC CROSSBANI) VENEER FOR AUTOMATIC PLYWOOD LAYUP EQUIPMENT 4 Claims, 8 Drawing Figs.

US. Cl 198/29, 271/50 Int. Cl ..B65g 47/22, B65h 9/14 Field of Search 198/34, 35,

[56] References Cited UNITED STATES PATENTS 1,705,505 3/1929 Spiess 271/53 3,194,382 7/1965 Nigrelli 198/34 Primary ExaminerRichard E. Aegerter Attorney-Wells, St. John & Roberts ABSTRACT: An indexing mechanism is disclosed for intermittcntly feeding crossband veneer sheets to a plywood layup station. The indexing mechanism includes a vacuum feeder for successively conveying crossband veneer sheets to a stop means. The stop means includes a cylinder horizontally mounted transverse to the direction of travel with a flange thereon normally extending into the path of the sheets. The cylinder is rotated by a intermittent drive to intermittently feed the crossband to the plywood layup station with considerable precision.

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BACKGROUND OF THE INVENTION This invention relates to plywood layup equipment and more particularly to indexing mechanisms for feeding core sheets crosswise to a layup station.

This application is a companion application to two copending applications, Ser. No. 8l4,58l, Method and Apparatus for Automatically Laying Up Plywood Panels"; and Ser. No. 814,580, Vacuum Feeder for Veneer Core Sheets now U.S. Pat. No. 3,533,518 granted Oct. 13, 1970.

One of the principal obstacles thwarting the development of automatic layup equipment is in the inability to machine handle core material, particularly the crossband sheets. The grain of the crossband sheets runs perpendicular to the length rendering the sheets quite limp and fragile in the major dimension. Also the crossband sheets are generally of low qualityhaving cracks, knots, knotholes and other defects therein. Often the crossband sheets are constructed from several smaller veneer sheets 4 feet in length which are placed side by side until the 8-foot dimension is reached. The smaller pieces are sometimes held together by string, tape or by edge gluing. The resultant crossband sheets are quite fragile and very awkward to handle. As a consequence, most plywood is layed up by hand with the small veneer core pieces being positioned side by side into a full 4 X8 crossband sheet on a face sheet without directly interconnecting the small veneer core pieces together.

A further problem encountered in attempting to develop automatic plywood equipment is the inability to efficiently convey and index a veneer sheet in a timed relationship to a layup station with considerable edge alignment precision so that the resulting plywood panels have square corners and uniform sides.

One of the principal objects of this invention is to provide an indexing mechanism for precision feeding and conveying core sheets to a layup station, such as the layup station described in the copending US. application Ser. No. 814,581, which is capable of economically and efficiently machine handling core or crossband sheets.

An additional object of this invention is to provide an indexing mechanism that is inexpensive to manufacture, efficient in operation and easy to maintain.

A further object of this invention is to provide indexing means for accurately aligning the leading edge of the crossband material as it is fed crosswise and feeding the aligned crossband sheet to the layup station without damaging the delicate edges.

These and other objects and advantages of this invention will become apparent upon the reading of the following detailed description.

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

FIG. 1 is a fragmentary bottom view of an indexing mechanism for feeding core veneer sheets to a layup station;

FIG. 2 is a vertical cross-sectional view taken along line 2- 2 in FIG. 1 showing a core veneer sheet abutting a stop means;

FIG. 3 is an enlarged fragmentary vertical cross-sectional view similar to FIG. 2 except showing the stop means moving from the leading of the core sheet to permit movement of the core sheet;

FIG. 4 is a vertical cross-sectional view similar to FIG. 3 ex cept showing the stop means moved out of the path of the sheet;

FIG. 5 is a similar view to FIG. 4 except showing further movement of the stop means as the sheet is moving thereby;

FIG. 6 is a cross-sectional view similar to FIG. 5 except showing the stop means engaging the trailing end of the sheet being fed to deflect the trailing end out of the path of a subsequent sheet that is being received at the stop means;

FIG. 7 is a plan illustration view of the leading edge of a core sheet before it engages the stop means;

FIG. 8 is a view similar to FIG. 7 except showing the core sheet engaging the stop means to align the leading edge of the sheet against the stop means.

DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT Referring in detail to FIGS. 1 and 2, there is shown an indexing mechanism generally designated by the arrow I0 for feeding and indexing core sheets S to a layup station, such as the one described in the copending application, Ser. No. 814,580, now Pat. No. 3,533,518. The sheet illustrated in FIG. 1 is composed of four smaller veneer pieces a, b, c and d having grains running in a 4-foot direction. The sheets are placed against each other in side-by-side relationship to make up the 8-foot dimension. To facilitate preliminary handling two

strings

8 and 9 are strung in the major direction across the pieces a, b, c and d to hold the sheet together. The

strings

8 and 9 are attached to the sheet at various locations by spot gluing or by other similar methods. In the formation of the core sheets S the side edge generally is somewhat uneven as shown in FIG. 7. Part of the purpose of indexing mechanism 10 is to align the ends of the pieces a, b, c and d in a straight line in a manner shown in FIG. 8 so that when the core sheet is layed up it will form a continuous edge with the face sheets.

Indexing mechanism I0 includes a feeding or conveying means 11 that successively propels the core sheets crosswise in a horizontal plane X with the major dimension of the sheets transverse to the direction of travel. An elongated stop means 12 is horizontally mounted for rotation about a horizontal axis Z that is spaced vertically above the horizontal plane X and transverse to the direction of travel of the sheets. The feed means propels the sheets in the horizontal plane X in a directionindicated by the arrow against the stop means. The stop means 12 projects into the horizontal plane X for stopping the forward movement of the sheet and to align the leading edge of the sheet parallel with the horizontal axis Z.

The stop means 12 is rotated in a single direction (arrow 14) about the horizontal axis Z by an intermittent drive means 13. The intermittent drive means I3 is synchronized so that the core sheets arrive at the layup station at precise. intervals in the layup sequence.

The indexing mechanism 10 includes a main frame 15 having two spaced

upright columns

16 and 17 positioned to the sides of the path of the sheets. The feeding means is mounted on the frame 15 and includes a vacuum feeder 18. The forward end of the feeder is mounted to

columns

16 and 17 for successively feeding the core sheets S along the horizontal plane X between the columns. The vacuum feeder I8 includes a vacuum hood 20 that has a downwardly directing opening for directing vacuum to hold the core sheets S along the bottom of the hood defining the horizontal plane X. A vacuum duct 21 is connected to a hood for directing a source of vacuum to the hood.

A plurality of continuously rotating rollers 22 are mounted in the bottom opening of the hood 20 transversely to the direction of movement of the sheets. The individual rollers shown in FIG. 2 are identified by 22a, 22b and 22c. The ends of the rollers 22 extend through the sides of the hood 20 and are rotatably mounted in bearings 23 (FIG. 1). The volume between the rollers is identified as chambers 24a, 24b and 24c for applying the vacuum pressure to the upper part of the sheets. The rollers move the sheets forward against the stop means applying a positive force to the sheets to start the sheets moving again when the stop means is released.

The stop means 12 includes an elongated hollow cylinder 25 horizontally mounted between the

columns

16 and 17 for rotation about the horizontal axis. The length of the cylinder should be equal to or greater than the length of the sheets. Stub shafts 26 and 27 are mounted in and extend from the ends of the cylinder. The stub shafts are rotatably mounted in bearings 28 and 29 respectively that are affixed to the

columns

16 and 17 respectively. The outside radius of the cylinder is equal to or greater than the distance from the horizontal axis 2 to the horizontal plane X. In this manner the outside surface of the cylinder 25 engages the upper surface of the sheets to stabilize and vertically support the sheets. A sprocket 31 is fixed to stub shaft 26.

The stop means 12 includes an abutment flange or blade 33 that extends outward from the side of the cylinder and normally into the path of the core sheets for receiving the leading edge of the core sheets. The blade 33 is substantially the same length as the cylinder 25 and is aligned parallel with the horizontal axis Z to align the leading edge of the sheet thereto. The blade 33 extends from the cylinder at an angle A (FIG. 2) to a radius 35 of the cylinder intersecting the blade forming a wedge crotch between the blade and the outer surface of the cylinder. One side of the blade serves as an abutment surface 34 for receiving the leading edge of the sheets.

The crotch between blade and cylinder is filled to prevent the leading edge of the blade from becoming wedged therebetween. The blade 33 has a smooth curved end 38 (FIGS. 3 and 6) that will not scrape or damage the upper surface of the core sheet.

The intermittent drive means 13 includes a chain 40 that extends from the sprocket 31 to a sprocket 41 mounted on the output side of the intermittent drive box device 42. The intermittent drive box 42 is a commercially available item in which the rotational speed of the cylinder 25 may be varied during the 360 revolution. An input shaft 43 extends from the drive box device to a synchronous motor 43a.

The intermittent drive box 42 is designed to rotate the cylinder at a variable speed during each revolution. Initially the cylinder smoothly accelerates slowly to permit the rolls 22 to bring the sheet up to speed while maintaining the leading edge aligned against the blade (FIG. 3). Otherwise, if the blade moved out of the way while the sheet was being accelerated, there is a good possibility the sheet will become askewed with the leading edge out of transverse alignment. It has been found that with this apparatus that the sheets are brought up to speed (100 feet per minute) within a distance of about 3 inches. After the sheet engaging the stop is brought up to full speed, the rotation of the cylinder rapidly accelerates to move the blade 33 from the leading edge as shown in FIG. 4. After the blade 33 is out of the path of the sheet, the cylinder is rotated at a decreasingly slower rate to bring the blade down against the trailing end of the sheet to deflect the end downward to receive the leading edge of the succeeding sheet. By this arrangement the sheets can be closely spaced and accurately aligned. This overlapping feature enables the layup time to be shortened plus providing substantial time adjustment to meet varying conditions of high production rates.

The outer surface of the cylinder 25 maintains contact with the upper surface of the sheet to provide substantial support and stability as the sheet moves past the stop. An example of an intermittent drive box for providing variable acceleration during each revolution is disclosed in U.S. Pat. No. 2,896,949.

The drive roller 44 is mounted immediately in front of the stop means 12 to support and to move the sheets forward as the sheets are fed past the stop means by the vacuum feeder 18. The drive roller 44 is suspended between bearings 45 (FIG. 1) that are affixed on

flanges

47 and 48 affixed to the

column

16 and 17 respectively. A gearbox 50 is mounted to one end of the drive roller 44 with a pulley 51 mounted on the input shaft of the gearbox. A belt 52 extends from the pulley 51 to a synchronous motor 53 mounted on the column 16.

A nip roller 54 is rotatably mounted immediately above the drive roller 44 on pivot arms 56 that extend from the

flanges

47 and 48. The nip roller maintains the sheet against the drive roller 44 to minimize slippage between the drive roller 44 and the sheets to move the sheets in a precise speed.

It should be understood that the construction of the stop means 12 enables the index mechanism to align the leading edge of this sheet in a straight line and to align the leading edge parallel with the horizontal axis Z. The release of blade 33 is with considerable precision and stability to maintain the leading edge in alignment and in precise position along the plane X.

Having thus described the preferred embodiment of this invention, the invention is defined as follows.

What is claimed as the invention is:

1. An indexing mechanism for intermittently feeding veneer core sheets perpendicular to the major dimension (crosswise) to a plywood layup station, said indexing mechanism comprismg:

a. a feeding means for successively feeding core sheets crosswise in a horizontal plane in a path toward the plywood layup station;

b. an elongated stop means horizontally mounted for rotational movement in a single direction about a horizontal axis which is vertically spaced from the horizontal plane, said stop means having a length substantially equal to or greater than the length of the core sheets, said stop means having an abutment extending radially therefrom for projecting into the path of the sheets wherein the abutment has an abutment surface facing in the opposite direction to the direction of rotation for receiving the leading edge of each sheet to stop the movement of said sheet and to align the leading edge of the said sheet parallel with the horizontal axis;

c. an intermittent drive operatively connected to the stop means for intermittently rotating the stop means 360 to remove the abutment from the path of the first sheet to permit the forward movement of the sheet and to reposition the abutment in the path of the succeeding second sheet in preparation for receiving the leading edge of the succeeding second sheet against the abutment surface in which the intermittent drive rotates the stop means to bring the abutment against the trailing end of the first sheet to deflect said trailing end vertically out of the path of the succeeding second sheet to receive the leading edge of the succeeding second sheet against the abutment surface with the first and second sheets overlapping.

2. An indexing mechanism as defined in claim I wherein the stop means includes an elongated cylinder having an outer radius equal to or greater than the distance from the horizontal axis to the horizontal plane for supporting the sheets with said abutment extending outward from the cylinder and the abutment surface inclined to a radius of the cylinder in a direction opposite to the direction of rotation.

3. An indexing mechanism as defined in claim 1 wherein the feeding means includes a vacuum feeder having a plurality of rotating rollers spaced along the bottom thereof for successively conveying the sheets crosswise in a horizontal plane against the abutment and for conveying the sheet past the stop means when the abutment is rotated out of the path of the sheets.

4. An indexing mechanism for intermittently feeding plywood veneer sheets to a layup station;

a. a continuously moving conveying means for supporting and successively moving the sheets along a selected path at a prescribed speed to the layup station;

. stop means mounted along the selected path upstream of the layup station, said stop means having an abutment surface that is rotatable about an axis transverse to the selected path for projecting into and out of the path of sheets; and

. an intermittent drive means operatively connected to the stop means for intermittently rotating the abutment surface into the path of the sheets to engage a leading edge of a sheet to stop the movement of the sheet on the continuously moving conveying means and align the leading edge of the sheet with the transverse axis and for subsequently rotating the abutment surface at a sufficiently slow acceleration to allow the continuously moving conveying means to accelerate the stopped sheet to the rotating the abutment surface at a faster acceleration to disengage the abutment surface from the leading edge and move the abutment surface out of the path of the sheets.

Claims

1. An indexing mechanism for intermittently feeding veneer core sheets perpendicular to the major dimension (crosswise) to a plywood layup station, said indexing mechanism comprising: a. a feeding means for successively feeding core sheets crosswise in a horizontal plane in a path toward the plywood layup station; b. an elongated stop means horizontally mounted for rotational movement in a single direction about a horizontal axis which is vertically spaced from the horizontal plane, said stop means having a length substantially equal to or greater than the length of the core sheets, said stop means having an abutment extending radially therefrom for projecting into the path of the sheets wherein the abutment has an abutment surface facing in the opposite direction to the direction of rotation for receiving the leading edge of each sheet to stop the movement of said sheet and to align the leading edge of the said sheet parallel with the horizontal axis; c. an intermittent drive operatively connected to the stop means for intermittently rotating the stop means 360* to remove the abutment from the path of the first sheet to permit the forward movement of the sheet and to reposition the abutment in the path of the succeeding second sheet in preparation for receiving the leading edge of the succeeding second sheet against the abutment surface in which the intermittent drive rotates the stop means to bring the abutment against the trailing end of the first sheet to deflect said trailing end vertically out of the path of the succeeding second sheet to receive the leading edge of the succeeding second sheet against the abutment surface with the first and second sheets overlapping.

2. An indexing mechanism as defined in claim 1 wherein the stop means includes an elongated cylinder having an outer radius equal to or greater than the distance from the horizontal axis to the horizontal plane for supporting the sheets with said abutment extending outward from the cylinder and the abutment surface inclined to a radius of the cylinder in a direction oppOsite to the direction of rotation.

4. An indexing mechanism for intermittently feeding plywood veneer sheets to a layup station; a. a continuously moving conveying means for supporting and successively moving the sheets along a selected path at a prescribed speed to the layup station; b. stop means mounted along the selected path upstream of the layup station, said stop means having an abutment surface that is rotatable about an axis transverse to the selected path for projecting into and out of the path of sheets; and c. an intermittent drive means operatively connected to the stop means for intermittently rotating the abutment surface into the path of the sheets to engage a leading edge of a sheet to stop the movement of the sheet on the continuously moving conveying means and align the leading edge of the sheet with the transverse axis and for subsequently rotating the abutment surface at a sufficiently slow acceleration to allow the continuously moving conveying means to accelerate the stopped sheet to the prescribed speed while maintaining the abutment surface in engagement with the leading edge until the stop sheet is accelerated to the prescribed speed to maintain the leading edge alignment during the sheet acceleration and then rotating the abutment surface at a faster acceleration to disengage the abutment surface from the leading edge and move the abutment surface out of the path of the sheets.