CA2456958A1

CA2456958A1 - Longitudinal sticker placing method and apparatus

Info

Publication number: CA2456958A1
Application number: CA 2456958
Authority: CA
Inventors: Daniel A. Grinder
Original assignee: Individual
Current assignee: Individual
Priority date: 2004-03-09
Filing date: 2004-03-09
Publication date: 2005-09-09

Abstract

An sticker placing method and apparatus for placing stickers between the layers of lumber in a lumber stack is disclosed, comprising a means for conveying the stickers to a plurality of sticker storage hoppers, means to place individual stickers into sticker carriers, means to translate the sticker carriers with the stickers to a desired position on the lumber stack, and means to strip the stickers longitudinally from the sticker carriers, leaving the stickers in desired locations on the lumber stack. The apparatus of the present invention may be located on a side of the lumber stack opposite to the lumber stacker and hoist mechanisms. The placement of the stickers may be timed with the lumber stacker so that a layer of lumber may be deposited on top of the stickers before the sticker carriers have completely retracted from the lumber stack.

Description

PATENT APPLIGATION
INVENTION: LONGITUDINAL STICKER PLACING METHOD AND
APPARATUS
INVENTOR: DANIEL A. GRINDER
APPLICANT: DANIEL A. GRINDER

LONGITUDINAL STICKER PLACING METHOD AND APPARATUS
Description FIELD OF THE INVENTION
The present invention relates to a sticker placing method and apparatus for placing stickers between successive layers of lumber on a lumber stacker, as is common practice in modern sawmills.
BACKGROUND OF THE INVENTION
Prior art in the field of sticker placing fall into three general categories.
In the first category, stickers are dispensed onto a lumber stack from a storage means located over top of the lumber stack, and the sticker placing apparatus is then moved generally upward out of the way while a layer of lumber is placed by the stacker onto the stickers. With each successive layer of lumber and stickers added to the lumber stack, the lumber stack is indexed downward by a hoist so as to maintain a constant height of the top of the lumber stack. It is desirable to place a sticker as near as possible to each end of the lumber stack. The stickers at the ends of the lumber stack can shake off due to mechanical vibration before the next layer of lumber is in place to hold the stickers. The result of missing stickers is splitting and warping of the lumber during kiln drying. A further disadvantage of the first category is the technical difficulty in placing stickers on their flat side due to dimensional inconsistencies in both the lumber and stickers inherent to the properties of sawn wood. Canadian Patent CA 2345861, Paul Halper, laid open October 30, 2002 depicts a recent example of this first category. In the second category, stickers are dispensed from a storage means into an array of carriers or troughs, which are integral with the array of stacker forks, so that the stickers are carried along with and beneath the layer of lumber onto the lumber stack, and the stickers are placed securely beneath the layer of lumber as the stacker forks are withdrawn from the lumber stack. A
disadvantage of this second category is that the mechanism for loading the stickers into the carriers on the stacker forks is interlaced with the stacker fork mechanism, resulting in a congested mechanical system. Access to the second category of sticker placing devices is both difficult and hazard prone. Furthermore, the stickers are necessarily transported to a loading position at an elevation lower than the starker forks, thus requiring a complex loading apparatus to lift each stick into a carrier or trough against the force of gravity.
Canadian Patent CA 2215460, Thomas Best, laid open April 4, 1998, and CA
2409513, Sydney Lunden, laid open April 26, 2003 depict recent examples of this second category.
In the third category, the stickers are spaced apart on a conveyor, which is located on the opposite side of the lumber stack from the starker forks. The stickers are grasped at their ends nearest the lumber stack and rotated through an arc about a horizontal pivot axis perpendicular to the stickers so as to place the stickers in spaced apart array on top of the lumber stack. A disadvantage of this third category is similar to that of the first category in that the stickers are subject to falling off the ends of the lumber stack before a subsequent layer of lumber is placed over the stickers. A further disadvantage of the third category is the need to maintain a large clear area above the sticker infeed conveyor and the lumber package where the stickers travel through their arc. Canadian Patent application CA
2356584, Gerard Hamel, laid open March 4, 2003 depicts a recent example of this third category.
The apparatus of the present invention overcomes the deficiencies in prior art designs by depositing the stickers into a carrier device by simple means advantageously utilizing the force of gravity, by positively gripping each sticker as it is transported into its desired position over the lumber stack, by providing sticker placement below the layer of lumber as the layer of lumber is placed on the lumber stack, and by locating the sticker placement mechanisms substantially in an accessible area on the opposite side of the lumber stack from the starker forks mechanism,. Furthermore, the apparatus of the present invention is advantageously compatible for retro-fit into existing lumber mill layouts.
SUMMARY OF THE INVENTION
The Sticker Placing Apparatus of the present invention comprises:

a sticker feeder of known art;
a sticker distributing conveyor of known art;
an array of sticker hoppers of known art;
a sticker stop integral with each sticker storage hopper;
a sticker clamp integral with each sticker storage hopper;
an array sticker carriers;
an array of sticker stripper arms;
a translatable frame on which the sticker carriers are mounted, hereinafter referred to as a carriage support frame;
a drive means of known art for the translatable frame;
a lumber stacker of known art;
a control means, for coordinating the motions of all related components;
a support means;
The sticker feeder, the sticker distributing conveyor, and the array of sticker hoppers may be of known art, configured according to common practice in modern sawmills, or the sticker feeder may be an adaptation of the Lumber Turning and Feeding Apparatus disclosed in CA 2426303 filed April 22, 2003, by the inventor of this present invention, not laid open as of the date of this present patent application, adapted to deal groups of more than one sticker into a single space between the lugs of the sticker distributing conveyor.
If the stickers are dealt in groups instead of individually, it is advantageous to run the sticker distributing conveyor at a slower speed, thus providing more controlled handling of the stickers, and providing a longer period of time between the lugs of the sticker distributing conveyor during which the sticker hopper diverters move to and from their open and closed positions.

The sticker stop and sticker clamp, which are mounted integral to the sticker hopper, may be actuated by inflatable flexible bellows and spring return means, wherein the sticker stop and the sticker clamp are elongate members of strong and flexible material rigidly attached to the sticker hopper at one end, and pre-bent to act as a leaf spring to collapse the inflatable flexible bellows at times when air pressure is not delivered to the inflatable flexible bellows. Alternatively, other means for clamping and holding sticks in similar hoppers are in common use and may be applied on the apparatus of the present invention.
The sticker carrier may consist of an inner shaft and an outer sleeve, either or both of which may be rotatably mounted to the carriage support frame. The outer sleeve may include at least one support bar for the purpose of supporting the sticker after the sticker is released from the sticker hopper. The support bar may be continuous, following the approximate size and shape of a sticker, or the support bar may be intermittent so as to support the sticker at strategic locations for securely gripping the stick through the motions of the sticker placing cycle. The inner shaft may include at feast one pincher bar for the purpose of holding the sticker positively against the support bar. The function of the sticker carrier is to receive a sticker from the sticker hopper, orient the rectangular sectioned sticker to lie flat in a horizontal plane, translate the sticker from a location adjacent to the sticker hopper to a second location on top of a lumber stack, release the sticker so that the sticker remains in a flat orientation on the lumber stack while the sticker carrier retracts to an original position to receive another sticker from the sticker hopper.
The sticker stripper arm may be mounted on a retracting linkage so as to be out of the path of moving parts and materials such as the sticker carrier, the sticker, the layer of lumber as it is placed onto the lumber stack, and the stacker forks during the part of the sticker placing cycle when the sticker is translated from a starting location adjacent to the sticker hopper until the sticker is in an ending position on the lumber stack.
The sticker stripper arm is then moved into a holding position in line with an end of the sticker nearest the sticker hopper, so that as the sticker carrier is retracted, the sticker is held by the sticker stripper to ensure that the sticker remains in its desired longitudinal position with respect to the lumber stack, and that the sticker does not carry back with the retracting sticker carrier. Furthermore, the sticker stripper serves to hold back any lumber from the layer of lumber that rests on the sticker carrier as the starker forks and the sticker carrier withdraw, and thereby provides a consistent vertical face on the side of the lumber stack adjacent to the sticker stripper arm.
The starker may be of conventional design commonly used in modern sawmills where a layer of lumber is transported laterally from an accumulating conveyor on an array of starker forks, to the top of an adjacent lumber stack. The starker forks travel in an elevated position until the layer of lumber is aligned approximately vertically above the lumber stack, then the starker forks are lowered to the top of the lumber stack before the starker forks are retracted to a starting position. An array of fixed or movable stops hold back the layer of lumber on the starker side of the lumber stack while the starker forks are retracted, providing a consistent vertical face on the side of the lumber stack adjacent to the starker. The lumber stack is supported by an indexing hoist which lowers the lumber stack by a desired distance each time a layer of Lumber is placed onto the top of the lumber stack, so as to maintain the top of the lumber stack at a constant height with respect to the starker forks and the sticker placing apparatus.
It is an object of this invention to provide a sticker placing apparatus with the following advantages over prior art:
a) Consistent and accurate placement of the stickers in a lumber stack, b) Placement of stickers below a simultaneously placed layer of lumber on a lumber stack, b) Open access for operating and maintenance personnel, c) Suitable for retro-fit to existing lumber production fines without significant modifications to existing or adjacent equipment, d) High speed operating capability.

BRIEF DESCRIPTION OF THE DRAWINGS
The invention will be better understood by reference to the accompanying drawings, wherein:
Fig. 1 is an elevation view, depicting the sticker placing apparatus of the present invention as installed between a sticker infeed conveyor and a lumber stacker.
Fig. 2 is an elevation view, along section line 2-2 of Fig. 1.
Fig. 3a is a detail view as in Fig. 1, depicting one sticker placing unit.
Fig. 3b is an elevation view as in Fig. 2, projected orthographically with respect to Fig. 3a.
Fig. 4 is an elevation view as in Fig. 2, depicting another stage in the operation of the present invention.
Fig. 5 is an elevation view as in Fig. 2, depicting another stage in the operation of the present invention.
Fig. 6a-6c are elevation views as in Fig. 3a, depicting various stages of stick placer operation, according to a first preferred embodiment of the present invention.
Fig. 7a-7c are elevation views as in Fig. 3a, depicting various stages of stick placer operation, according to a second preferred embodiment of the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
In a first preferred embodiment, as best seen in Fig. 1 and 2, stickers 10 accumulate in a single layer on an infeed conveyor 12 and are intermittently held back by feeder stops 14.
Stickers 10 are fed singly, or in groups of two or more stickers, in direction A by a sticker feeder 16. The group of stickers 10 lie edge to edge, and the movement of the group of stickers by sticker feeder 16 is timed to coincide with the spaces between lugs 18 of an overhead Lugged sticker distributing conveyor 20. The stickers 90 are conveyed by the sticker distributing conveyor 20 across the tops of an array of sticker storage hoppers 22 until the stickers 10 are diverted into a sticker storage hopper 22 with an open diverter gate 24, which allows the stickers 10 to accumulate in the storage hoppers 22 to a level as determined by an upper sensing means 26. Details of the sticker hopper 22 are best seen in Fig. 3a and 3b. The sticker hoppers 22 may be vertical, or sloped as shown.
Sloped sticker hoppers 22 provide an advantage in that the stickers 10 crowd by gravity to one side of the sticker hopper 22, and are therefore less likely to jam in the clearance space between the sides of the sticker hopper 22. The stickers 10 are retained in the sticker hopper 22 by a sticker stop 28 and sticker clamp 30. As best seen in Fig. fia to 6c, a sticker carrier 32 is positioned strategically below the sticker hopper 22 so that a sticker 10, when released by the sticker stop 28 will drop into a space adjacent to the stick carrier 32 confined on one side by at least one carrier support bar 34, and on the opposite side by at least one carrier pinch bar 36, and on the lower edge by the carrier sleeve 38. Pinch bar 36 is rigidly attached to a carrier inner shaft 40, which is pivotally mounted to a carriage support frame 42 through bearings 44. The carrier inner shaft 40 is caused to rotate by pinion gear 46 and rack 48. When rack 48 is selectively translated on its longitudinal axis, pinion gear 46 is caused to rotate. !t can be seen that by ganging together an array of racks 48 to mesh with an array of pinions 46, which in turn drive an array of carrier inner shafts 40, all of the array of inner shafts 40 will be caused to rotate in unison as the rack 48 is translated on its longitudinal axis. Carrier support bar 34 is rigidly attached to carrier sleeve 38. Carrier sleeve 38 may be a hollow shaft pivotally mounted circumferentially over carrier inner shaft 40, and may be retained in a longitudinal axis with respect to the carrier inner shaft 40 by bearings 42, so as to be caused to travel in unison with carrier inner shaft 40 in a longitudinal direction, while remaining free to rotate in the circumferential direction. Carrier sleeve 38 may be caused to rotate by a drive means similar to the pinion gear 46 and rack 48 of the carrier inner shaft 40, or by other means such as a crank arm 50 as shown. It can be seen that by ganging together an array of crank arms 50 to a common actuator bar 52, all of the array of carrier sleeves 50 will be caused to rotate in unison as common actuator bar 52 is selectively translated on its longitudinal axis. When a sticker 10 is dispensed into the sticker carrier 32, the sticker carrier 32 together with the sticker 10 are rotated until the rectangular sectioned sticker 10 lies in a substantially flat position, remaining clamped between the carrier support bar 34 and the carrier pinch bar 36. As seen in Fig. 4, the array of sticker carriers 32 with stickers 10 clamped in the flat position is then translated in the direction of the stickers' 10 longitudinal axis so as to pass above the top of a lumber stack 60 until the ends of the stickers 10 are approximately in vertical alignment with the sides of the lumber stack 60.
At approximately the same time, a layer of lumber 64 is carried by stacker forks 66 from the opposite side of the lumber stack 60 so as to pass above the stickers 10 and sticker carriers 32 until the layer of lumber 64 is in approximate vertical alignment with the lumber stack 60. As seen in Fig. 5, both the sticker carriers 32 and the stacker forks 66 are then lowered to allow their tips to rest on the top of the lumber stack 60. The carrier pinch bar 36 is rotated away from the sticker 10 to release the sticker 10 and to be clear of the layer of lumber 64 when the sticker carrier 32 is withdrawn. An array of stripper arms 70 moves into position to prevent the stickers 10 and the layer of lumber 64 from being dragged along with the sticker carriers 32 as the sticker carriers 32 are withdrawn.
The sticker carriers 32 and the stacker forks 66 withdraw from the lumber stack 60 at approximately the same time, causing the middle of the layer of lumber 64 to rest on the stickers 10 first.
When the sticker carriers 32 are fully withdrawn from the lumber stack 60, the stickers 10 are held securely between the layers of lumber 64, and the sticker carriers 32 are raised to an elevated position for receiving the next array of stickers 10. The carrier support bar 34 and carrier pinch bar 36 are rotated to respective positions suitable for receiving the next sticker 10.
As seen in Fig. 7a to 7c, in a second preferred embodiment of the present invention, stickers 10 are distributed to an array of sticker hoppers 72 as in the first preferred embodiment described above. The sticker hoppers 72 have a curved section at the lowermost end to cause the lowermost stickers 10 to lie in approximately horizontal orientation. The stickers 10 are retained in the sticker hopper 72 by a sticker clamp 74.
The sticker carrier 32 is positioned strategically adjacent to the sticker hopper 72 such that a sticker 10, when released by the sticker clamp 74 will be caused to slide by the force of gravity acting on the stickers 10 in the sticker hopper 72, laterally onto a carrier support bar 34. The sticker 10 is thus confined on one side by at feast one carrier support bar 34, and on the opposite side by at least one carrier pinch bar 36, and on one edge by the carrier sleeve 38. After a sticker 10 is dispensed, the sticker clamp 74 is engaged to hold back the stickers 10 remaining in the sticker hopper 72. The array of sticker carriers 32, thus loaded with stickers 10, is then translated in the direction of the stickers' 10 to be placed into a lumber stack 60 as described in detail for the first preferred embodiment.
When the sticker carriers 32 are fully withdrawn from the lumber stack 60, the stickers 10 are held securely between the layers of lumber 64, and the sticker carriers 32 are raised to an elevated position for receiving the next array of stickers 10. In this second preferred embodiment, it can be seen that the carrier support bar 34 is not required to rotate at any time during the operating cycle, and could therefore be rigidly mounted to the carrier support frame 42, thus eliminating the components for rotating the carrier sleeve 38, and allowing the carrier inner shaft 40 to be supported by the carrier sleeve 38.
In both the first and second preferred embodiments of the present invention as described above, the difficulties in prior art are overcome. An advantage of the second preferred embodiment over the first preferred embodiment is greater simplicity of construction and consequent lower cost. A third preferred embodiment comprises all the elements of the second preferred embodiment, with the omission of the carrier pinch bar 36, the carrier inner shaft 40, the pinion gear 46 and the rack 48. In this third preferred embodiment, the operating sequence is as described above for the second preferred embodiment, omitting the carrier pinch bar. Further mechanical simplification exists, but operating reliability and seed may be compromised due to the lack of positive clamping of the sticker 10 during its longitudinal translation.
As will be apparent to those skilled in the art in the light of the foregoing disclosure, many alterations and modifications are possible in the practice of this invention without departing from the spirit or scope thereof. Accordingly, the scope of the invention is to be construed in accordance with the substance defined by the following claims.

Claims

1. A longitudinal sticker placing method and apparatus for moving a plurality of generally parallel stickers from a starting position to an ending position on a lumber stack of, wherein the lumber in the lumber stack are oriented generally perpendicular to the longitudinal axis of the stickers, and wherein the top of the lumber stack is offset horizontally from the starting position of the stickers so that the stickers move from the starting position generally horizontally and in a direction parallel to the longitudinal axis of the stickers in order to align the ends of the stickers approximately to the edges of the lumber stack, comprising:
(a) a plurality of sticker carriers, (b) a plurality of sticker loading devices, (c) a plurality of sticker unloading devices, (d) a moveable carriage on which the plurality of sticker carriers are mounted, (e) a drive means for moving the carriage back and forth, (f) a control means for controlling the timing and sequence of operation of all related devices, (g) and a support frame.

2. The device of claim 1 wherein each sticker loading device comprises a hopper with at least two sides for containing a plurality of stickers in a vertical or slanted stack of one or more stickers, one sticker above another, and wherein the longitudinal axis of each sticker lies in an approximately horizontal plane, and wherein a retaining means holds the lowermost sticker at a position suitable for depositing the lowermost sticker into an adjacent, sticker carrier.

3. The device of claim 2 wherein the sticker loading device further comprises a feeder device for depositing a single stick into an adjacent sticker carrier.

4. The devices of claims 2 and 3 wherein the sticker carrier comprises an elongate member shaped so as to support the sticker in approximate parallel alignment with the elongate member.

5. The device of claim 4 wherein the sticker carrier further comprises a clamping means far holding the sticker securely to the sticker carrier, and wherein the clamping means is selectively engaged with and disengaged from the sticker.

6. The device of claim 5 wherein the sticker carrier comprises a rotatable inner shaft and a rotatable outer shaft concentric with the inner shaft, and wherein the outer shaft comprises a hollow elongate member with one or more arms extending approximately radially outward from the outer shaft so as to support a first face of the sticker in approximate parallel alignment with the sticker carrying device.

7. The device of claim 6 wherein the inner shaft comprises an elongate member with one or more arms extending approximately radially outward from the inner shaft so as to make clamping contact with a second face of the sticker opposite to the first face of the sticker.

8. The device of claim 7 wherein the inner shaft and the outer shaft may be rotated advantageously during the movement cycle of the sticker carrier so as to receive the sticker from the loading device, clamp the sticker to the sticker carrier, and release the sticker at a desired location over the lumber stack.

9. The devices of claims 6 to 8 wherein the outer shaft is not rotatable.

10. The devices of claims 6 to 8 wherein the inner shaft is mounted through rotatable bearings to the moveable carriage.

11. The device of claim 9 wherein the outer shaft is rigidly mounted to the moveable carriage.

12. The device of claim 4 wherein the sticker carrier is rigidly mounted to the moveable carriage.

13. The devices of claims 1 to 12 wherein a sticker unloading device comprises a selectively retractable holdback arm wherein the holdback arm, in a retracted position allows the sticker to pass freely during the extension stroke of the sticker carrier, and wherein the hold back arm in an extended position holds the sticker in a desired position with respect to the lumber stack during the return stroke of the sticker carrier.

14. The device of claim 13 wherein the holdback arm, in an extended position, prevents lumber which is resting on the sticker carrier from being carried along with the sticker carrier during the return stroke of the sticker carrier.

15. The devices of claims 1 to 14 wherein the sticker carrier further comprises a lifting means for selectively raising and lowering at least one end of the sticker carrier at advantageous times during the movement cycle of the sticker carrier.

16. The device of claim 15 wherein the sticker carrier further comprises a lifting means for selectively raising and lowering at least one end of the array of sticker carriers at advantageous times during the movement cycle of the sticker carriers.

17. The devices of claims 1 to 16 wherein the stick placing apparatus is located generally on the side of the lumber stack opposite from the location of a (umber stacking machine.