CA2986679A1 - Apparatus and method for delivering wood planks to a transverse bar conveyor-type machine - Google Patents

Abstract

A wood plank feeder for transferring wood plank from a conveyor to transversely moving parallel spaced-apart bars is described. The wood plank exits the conveyor in a direction substantially parallel to the spaced-apart bars. The wood plank feeder comprises a pair of rollers positioned downstream of the conveyor, at least one of the two rollers being rotationally driven by a power source. The wood plank feeder also comprises a support positioned downstream of the pair of rollers and over the transversely moving parallel spaced-apart bars. The wood plank flowing through the pair of rollers is directed over the support. A method for transferring wood plank from a conveyor to transversely moving parallel spaced-apart bars is also described.

Description

APPARATUS AND METHOD FOR DELIVERING WOOD PLANKS
TO A TRANSVERSE BAR CONVEYOR-TYPE MACHINE
TECHNICAL FIELD
[0001] The application relates generally to hardwood manufacturing machines and processes and, more particularly, to delivering wood planks to transverse bar conveyor-type machines such as end matchers.
BACKGROUND OF THE ART

[0002] In a typical hardwood manufacturing process, hardwood planks exiting moulder machines require their ends to be machined. Such hardwood planks are therefore directed, via a conveyor system, to an end matcher. Such end matchers include parallel spaced-apart bars, transversely moving over a fixed surface, for ferrying planks in a transverse direction and end-profilers positioned at either parallel extremities for machining such planks to the required dimensions. End matchers sometimes comprises side-shift rollers, over which the parallel spaced-apart bars are transversely moving, for positioning the hardwood planks in a parallel direction within the spaced-apart bars. In such end matchers, no more than 1 plank can be positioned between adjacent parallel spaced-apart bars; the machine that feeds the planks to the end matcher (known as the "Plank Feeder"), more specifically that deposits the planks in between the moving adjacent parallel spaced-apart bars, is therefore an important element of the hardwood manufacturing process.

[0003] In a first type of well-known end matchers, the Plank Feeder delivers planks to the end matcher in a perpendicular direction to the moving parallel spaced-apart bars of the end matcher, through the use of a linear feed conveyor positioned vertically substantially parallel to the end matcher, as shown, for example, in US
6,945,410 ("Stibbard"); such a system however is limited in terms of efficiency (from the point of view of being able to feed planks of different lengths in between each adjacent parallel spaced-apart bars) and processing speeds, meaning that a high efficiency end matcher (i.e. where one plank is placed in between each adjacent parallel spaced-apart bars) will have low processing speeds and vice-versa.
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[0004] In another type of well-known end matchers, the Plank Feeder consists in feeding planks to the end matcher through the use of an inclined chute and trap-door positioned above the end matcher; in such systems, the planks to slide down towards the trap-door and the trap-door opens up at the right moment so one plank at a time is deposited in between the moving parallel spaced-apart bars. There is a certain limit to the speed at which such Plank Feeder can operate, to ensure that the planks actually slide down the inclined part and are dropped in between the spaced-apart bars.

[0005] In cases where the spaced-apart bars move (and the speed at which the whole end matcher can operate) faster than the Plank Feeder can feed the planks, manual operators are positioned nearby and manually place planks in between spaced-apart bars which did not receive a plank from the Plank Feeder. However, the introduction of manual operations in a manufacturing process is not optimal in terms of efficiency.
The introduction of extra Plank Feeders is also not optimal as it leads to hardwood manufacturing machines with increased footprint.

[0006] There is therefore an ongoing need for higher efficiency (where the majority of adjacent parallel spaced-apart bars contains a plank) higher processing speeds end matchers, more specifically for Plank Feeder that can deposit planks, at high processing speeds, in between the majority of moving parallel spaced-apart bars of end matchers.
SUMMARY

[0007] In one aspect, there is provided a wood plank feeder for transferring wood plank from a conveyor to transversely moving parallel spaced-apart bars and wherein the wood plank exits the conveyor in a direction substantially parallel to the spaced-apart bars, the wood plank feeder comprising: a pair of rollers positioned downstream of the conveyor, at least one of the two rollers being rotationally driven by a power source, and a support positioned downstream of the pair of rollers and over the transversely moving parallel spaced-apart bars; wherein the wood plank flowing through the pair of rollers is directed over the support.

[0008] The wood plank feeder may comprise a plank position sensor for detecting a presence of a trailing edge extremity of the wood plank in between the pair of rollers, the plank position sensor being operationally linked to the at least one of the two rollers being rotationally driven by a power source at a rotational speed. The plank position sensor may cause the at least one of the two rollers being rotationally driven by a power source to reduce its rotational speed when the presence of a trailing edge extremity of the wood plank in between the pair of rollers is detected.

[0009] The pair of rollers may be moveable with respect to one another.

[0010] The at least one of the two rollers being rotationally driven by a power source may comprise a wood gripping surface and the pair of rollers may be subjected to a biasing force acting against a movement of the pair of rollers away from one another.

[0011] The wood plank feeder may comprise a bar gap sensor for detecting a position of at least one of the parallel spaced-apart bars vertically below the support, the bar gap sensor being operationally linked to the at least one of the two rollers being rotationally driven by a power source. When the presence of a trailing edge extremity of the wood plank in between the pair of rollers is detected, the bar gap sensor may cause the at least one of the two rollers being rotationally driven by a power source to stop rotating when an unsatisfactory position of the at least one of the parallel spaced-apart bars vertically below the support is detected and then to resume rotating when a satisfactory position of the at least one of the parallel spaced-apart bars vertically below the support is detected.

[0012] The wood plank feeder may comprise a bar gap sensor for detecting a position of at least one of the parallel spaced-apart bars vertically below the support, the bar gap sensor being operationally linked to the support. When the presence of a trailing edge extremity of the wood plank in between the pair of rollers is detected, the bar gap sensor may cause the support to be removed from underneath the wood plank when a satisfactory position of the at least one of the parallel spaced-apart bars vertically below the support is detected.

[0013] The wood plank feeder may comprise a bar gap sensor for detecting a position of at least one of the parallel spaced-apart bars vertically below the support, the bar gap sensor being operationally linked to the at least one of the two rollers being rotationally driven by a power source and being operationally linked to the support. When the presence of a trailing edge extremity of the wood plank in between the pair of rollers is detected, the bar gap sensor may cause the at least one of the two rollers being rotationally driven by a power source to stop rotating when an unsatisfactory position of the at least one of the parallel spaced-apart bars vertically below the support is detected and, when a satisfactory position of the at least one of the parallel spaced-apart bars vertically below the support is detected, to cause the at least one of the two rollers being rotationally driven by a power source to resume rotating and to cause the support to be removed from underneath the wood plank.

[0014] The support may be a horizontally displaceable plate. The bar gap sensor may cause the horizontally displaceable plate to be removed from underneath the wood plank when a satisfactory position of the at least one of the parallel spaced-apart bars vertically below the horizontally displaceable plate is detected, after a presence of a trailing edge extremity of the wood plank in between the pair of rollers has been detected.

[0015] The bar gap sensor, when a unsatisfactory position of the at least one of the parallel spaced-apart bars vertically below the horizontally displaceable plate is detected, may cause the at least one of the two rollers being rotationally driven by a power source to stop rotating and, when a satisfactory position of the at least one of the parallel spaced-apart bars vertically below the horizontally displaceable plate is detected, to cause the at least one of the two rollers being rotationally driven by a power source to resume rotating and to cause the horizontally displaceable plate to be removed from underneath the wood plank.

[0016] In another aspect, there is provided a method for transferring wood plank from a conveyor to transversely moving parallel spaced-apart bars, the method comprising:

causing a movement of the wood plank from the conveyor, in a direction substantially parallel to the spaced-apart bars, over such moving parallel spaced-apart bars at a determined translational speed; when the wood plank has reached a determined position over the moving parallel spaced-apart bars, reducing the determined translational speed of the wood plank; determining a position of at least one of the moving parallel spaced-apart bars below the plank; and performing only one of the following 2 steps:
if the at least one moving parallel spaced-apart bars is in an unsatisfactory position, reducing the determined translational speed of the wood plank to zero and holding such wood plank in a stationary position until the at least one parallel spaced-apart bar is in a satisfactory position, then, when the at least one moving parallel spaced-apart bars is in a satisfactory position, resuming the movement of the wood plank and letting such wood plank fall between 2 transversely moving parallel spaced-apart bars;
if the at least one moving parallel spaced-apart is in a satisfactory position, letting the wood plank fall between 2 transversely moving parallel spaced-apart bars.

[0017] The step of causing a movement of the wood plank from the conveyor may be performed by pinching the wood plank between two rollers, at least one of the two rollers being rotationally driven by a motor.

[0018] The determined position of the wood plank may be reached when a trailing edge extremity of such wood plank is located between the two rollers.

[0019] The satisfactory position of the moving parallel spaced-apart bars may be when a gap between adjacent moving parallel spaced-apart bars is positioned such that letting the wood plank, held over the moving parallel spaced-apart bars, will result in such wood plank falling between such adjacent moving parallel spaced-apart bars.

[0020] Further details of these and other aspects of the subject matter of this application will be apparent from the detailed description and drawings included below.

DESCRIPTION OF THE DRAWINGS

[0021] Reference is now made to the accompanying figures in which:

[0022] Fig. 1 is a schematic isometric view of a hardwood manufacturing machine comprising a linear conveyor and an end matcher pursuant to an embodiment of the invention;

[0023] Fig. 2 is an isometric view of the plank feeder of the hardwood manufacturing machine of Fig. 1;

[0024] Figs. 3-6 are cross-sectional view of the plank feeder of Fig. 2 in operation, showing a wood plank being processed through the plank feeder; and

[0025] Fig. 7 is an isometric view of the linear conveyor of the hardwood manufacturing machine of Fig. 1.
DETAILED DESCRIPTION

[0026] Fig. 1 illustrates a downstream portion of a hardwood manufacturing apparatus, more specifically the portion where hardwood planks 3, having a thickness T, a length L
and a width W, exiting moulder machines (the details of which are not shown) are carried, sequentially one after another, in a direction D1, by a linear conveyor 1 to an end matcher 2 and where, in turn, end matcher 2 carries hardwood planks 3 in a direction D2 for further processing Indeed, as is well known in the art, hardwood planks 3 exiting moulder machines need to have their ends further detailed. This is done by end matcher 2 which includes parallel spaced-apart bars 21, transversely moving over a combination of fixed surfaces 22 and side-shift rollers 23, 24 and 25 (the spaced-apart bars 21 moving hardwood planks 3 in direction D2 and side-shift rollers 23, 24 and 25 moving hardwood planks 3 within spaced-apart bars 21 in respective directions D3, D4 and D5) and end-cutters 26 and 27 positioned at lateral ends of end matcher 2 (for performing the needed detailing). Planks 3 carried in direction D2 (by moving parallel spaced-apart bars 21) therefore are moved (by side-shift roller 23) in direction D3 (so as to be positioned to be processed by end cutter 26), are then processed by end cutter 26, are then moved (by side-shift roller 24) in direction D4 (so as to be positioned to be processed by end cutter

27), are then processed by end cutter 27, are then moved (by side-shift roller 25) in direction 05 and then carried downstream and out of end matcher 2. For proper functioning of end matcher 2, no more than one plank 3 can be positioned between adjacent parallel spaced-apart bars 21. The deposit of plank 3 between adjacent parallel spaced-apart bars 21 is accomplished by the plank feeder 4.
[0027] Fig. 2 illustrates in more details the upstream portion of end matcher 2, including the plank feeder 4 which takes the planks 3 from linear conveyor 1 and deposits them, one at a time, in between moving parallel spaced-apart bars 21. The plank feeder portion comprises a support 41, a pinch roller 42 and a driving roller 43. Linear conveyor 1 has a carrying surface 11 to transport planks 3 to the plank feeder portion, more specifically to rollers 42 and 43. Driving roller 43 is positioned and dimensioned to assist in the continuous movement of plank 3 (in direction D1) and to assist in the pinching function of pinch roller 42; it is understood that any pinching elements, which do not hinder the continuous movement of plank 3, are possible pursuant to the invention. Pinch roller 42 is positioned and dimensioned to pinch plank 3 (in conjunction with driving roller 43) and to move plank 3 in direction D1 over support 41; pinch roller 42 is also known as an idle roller has it is not driven by a motor, but simply allowed to rotate freely.
With the assistance of a motor (not shown) however, driving roller 43 is driven at variable desired rotating speeds. Support 41, which receives plank 3 from rollers 42, 43, is positioned directly above end matcher 2; it is understood that any supporting element, which can support plank 3 and release it (as will be explained in more details below), is possible pursuant to the invention. The operation of the plank feeder portion, more specifically of support 41, pinch roller 42 and driving roller 43, is explained in more details as follows, with reference to Figs. 3-6.

[0028] Plank 3 is carried towards rollers 42, 43 by linear conveyor 1 in direction D1 as shown in Fig. 3 (for ease of understanding in Figs. 3-6, direction arrow A
represents the direction of movement of conveying surface 11 and direction arrow B represents the direction of movement of plank 3). When plank 3 reaches rollers 42, 43, it is pinched between such rollers 42, 43. In the current embodiment, driving roller 43 is vertically aligned with conveying surface 11 and is rotationally driven by a motor (not shown) and functions as the driving force to urge plank 3 towards support. Pinch roller 42, on the other hand, rotates freely so as to support and assist in the movement of plank 3. When no plank 3 is positioned between rollers 42, 43, the rotating surface of pinch roller 42 is located at a distance S from the rotating surface of driving roller 43 that does not exceed the anticipated thickness T of plank 3 and is preferably less than such thickness T. When plank 3 passes in between rollers 42, 43 such distance S is allowed to increase and a biasing force, pushing against the movement of pinch roller 42 and driving roller 43 away from one another, is applied. In combination with a gripping material present on driving roller 43, the biasing force pinches plank 3; consequently, the pair of rollers 42, 43 drive plank 3 towards support 41 (Fig. 4). In the current embodiment, driving roller 43, with a rotating surface made of wood gripping material, is not allowed to move vertically (i.e. no vertical freedom of movement) and pinching roller 42 is allowed to move vertically upward (i.e. has vertical freedom of movement) against a biasing force (which pushes pinching roller 42 back down); it is however understood that other combinations of rollers 42, 43, gripping surfaces, freedoms of movement and biasing forces, which accomplish the function of driving plank 3 from linear conveyor 1 to support 41, are possible pursuant to the invention. For example, without being limiting, rollers 42, 43 may both be driven by a motor and may both have gripping surfaces; in another non limiting example, the motor driven roller with a gripping surface may be the top roller, whereas the idle pinch roller may be the bottom roller.

[0029] As indicated above, support 41 is positioned over end matcher 2, more specifically over moving parallel spaced-apart bars 21. Top surface 41a of support 41 is positioned substantially parallel (horizontally) to conveying surface 11 and its vertical position does not exceed the vertical position of such conveying surface 11 and of driving roller 42;
consequently, plank 3, driven by rollers 42, 43 moves over support 41 and slides over top surface 41a. Rollers 42, 43 move plank 3 over support 41 until trailing edge extremity 31 of plank 3 is positioned (and still pinched) between such rollers 42, 43;
the rotational movement of rollers 42, 43 is then reduced (and may even be stopped as will be explained in more details below) such that plank 3 is supported at one end (trailing edge extremity 31) by rollers 42, 43 and at the other end (leading edge extremity 32) by support 41 (Fig. 5). Preferably, support 41 is sufficiently wide to support leading edge extremity 32 of any plank 3. It is however possible, pursuant to the invention, to have shorter supports 41 so long as the supporting function of plank 3 (in conjunction with rollers 42, 43) is achieved.

[0030] It is to be noted that, the higher the speed at which plank 3 is driven by rollers 42, 43, the more efficient plank feeder 4 will be; indeed, the faster plank 3 can be positioned over support 41 and on top surface 41a (as shown in Fig. 5), the sooner such plank 3 can be dropped between adjacent parallel spaced-apart bars 21 moving vertically below such support 41. At a minimum, rollers 42, 43 are able to carry plank 3 towards support 41 at higher speeds than the speeds at which linear conveyor 1 carry plank 3. A
plank position sensor 45 is positioned immediately upstream of rollers 42, 43 to detect the presence of plank 3. In the current embodiment, because plank 3 accelerates once it is pinched (and driven) by rollers 42, 43, a gap arises between sequential planks 3 being carried by linear conveyor 1, such that when plank position sensor 45 detects a gap, it means that trailing edge extremity 31 of plank 3 is positioned between such rollers 42, 43. It is understood that other means of determining when trailing edge extremity 31 of plank 3 is positioned (and still pinched) between such rollers 42, 43 are possible pursuant to the invention.

[0031] Once plank 3 is correctly positioned over the spaced-apart bars 21 moving vertically below (i.e trailing edge extremity 31 of plank 3 is held in between rollers 42, 43 and leading edge extremity 32 of plank 3 is held by top surface 41A of support 41, as shown in Fig. 5), a determination is made as to whether the time is right to drop plank 3 between adjacent parallel spaced-apart bars 21 moving below; in the current embodiment, this is accomplished via a bar gap sensor (not shown) which is able to determine if a gap between 2 adjacent parallel spaced-apart bars 211s located below support 41 such that, if support 41 is removed, plank 3 will fall and position itself properly in between such bars 21. If the time is not right (i.e. the gap sensor determines that the space-apart bars below are in an unsatisfactory position), the rotational movement of rollers 42, 43 is stopped (so as to stop the translational movement of plank 3) until a well-positioned gap between 2 adjacent parallel spaced-apart bars 21 is detected (i.e. the gap sensor determines that the space-apart bars below are in a satisfactory position). When this occurs, the bar gap sensor (not shown) sends a start signal to rollers 42, 43 (so that translational movement of plank 3 in direction D1 resumes) and an activation signal to support 41 (so that top surface 41a is removed from under plank 3, thereby allowing plank 3 to fall under its own weight); as a result, plank 3 is dropped between 2 adjacent parallel spaced-apart bars 21 and plank 3 can be further processed by end matcher 2 (Fig. 6). It is to be noted that, the higher the speed at which support 41 is removed from under plank 3 (more specifically top surface 41sa is removed from under plank 3), the more efficient plank feeder 4 will be (as the sooner such plank 3 can be dropped between adjacent parallel spaced-apart bars 21 moving vertically below such support 41). In the current embodiment, rollers 42, 43 are re-activated to push plank 3 in direction D1 before support 41 is removed from under plank 3 to ensure the correct placement plank 3 in between adjacent parallel spaced-apart bars 21.

[0032] It is understood that if, at the moment plank 3 is correctly positioned over the spaced-apart bars 21 moving vertically below (i.e. trailing edge extremity 31 of plank 3 is held in between rollers 42, 43 and leading edge extremity 32 of plank 3 is held by top surface 41A of support 41, as shown in Fig. 5), a determination is made that the time is right to drop plank 3 between adjacent parallel spaced-apart bars 21 moving below (i.e.
the gap sensor determines that the space-apart bars below are in a satisfactory position), the rotational movement of rollers 42, 43 does not need to be stopped; its rotational speed is simply reduced to a speed that will ensure that plank 3 is not propelled horizontally over and beyond end matcher 2 and top surface 41a is removed from under plank 3, thereby allowing plank 3 to fall under its own weight in between 2 adjacent parallel spaced-apart bars 21.

[0033] It should be noted that if it is determined that, when plank 3 is correctly positioned over the spaced-apart bars 21 moving vertically below (i.e. trailing edge extremity 31 of plank 3 is held in between rollers 42, 43 and leading edge extremity 32 of plank 3 is held by top surface 41A of support 41, as shown in Fig. 5), the time is right to drop plank 3 between adjacent parallel spaced-apart bars 21 moving below, the rotational movement of rollers 42, 43 does not have to be stopped (i.e. the translational movement of plank 3 does not have to be stopped) and support 41 can be removed from under plank 3.
In such instance, the rotational movement of rollers 42, 43 may have to be slowed down to ensure that plank 3 is not propelled horizontally over and beyond end matcher 2.

[0034] It should be noted that, in circumstances when the translational movement of plank 3 is stopped, it must be ensured that planks further upstream being carried by conveying surface 11 do not collide with trailing edge extremity 31 held in between rollers 42, 43. In most circumstances, there will be enough space with the upstream planks that no collision will occur; in certain circumstances, there might be a need to stop the upstream plank from travelling towards plank 3 (stopped between rollers 42, 43). In the current embodiment, this is addressed by stationary plate 48, located between linear conveyor 1 and rollers 42, 43, over which plank 3 is allowed to slide, and a pneumatic brake that can be activated (when need be) to pin down (and stop) a plank from progressing further over such plate 48. It is however understood that there are other ways to stop the translational movement of upstream planks towards rollers 42, 43 when need be.

[0035] Reference is made again to Figs. 3-6 to explain more generally the operation of the current embodiment. Linear conveyor 1 carries planks 3 on a moving conveying surface 1 (typically a belt) length-wise in single files (i.e. one after another) at speeds exceeding the speeds at which planks exit moulder machine i.e. at speeds exceeding about 200-350 ft/min (typical speeds at which planks exit moulder machine); in the current embodiment, linear conveyor 1 operates at about 600 ft/min. It has been found that the transfer step between linear conveyor 1 and end matcher 2 (i.e. the process by which plank 3 moves from linear conveyor 1 to end matcher 2) is where increases in efficiency can be found. In the current embodiment, planks 3 exits linear conveyor 1 in a direction D1 substantially perpendicular to the movement direction D2 of the parallel spaced-apart bars 21 of end matcher 2 i.e. substantially parallel to the parallel spaced-apart bars 21.
When leading edge extremity 32 of plank 3 reaches rollers 42, 43, it's linear speed is increased to approximately 800 ft/min, so as to bring it as fast as possible in position over the parallel spaced-apart bars 21 of end matcher 2 (in the embodiment shown in Fig. 3, driving roller 43, with its gripping surface, in combination with pinch roller 42, accomplishes this). As outlined above, to prevent plank 3 from prematurely falling down in end matcher 2, plank 3 is slid over plate 41, more specifically over top surface 41A, so that plank 3 is held over parallel spaced-apart bars 21 moving below. The time it takes rollers 42, 43 to place plank 3 in position over parallel spaced-apart bars 21 depends on its length; as length L of plank 3 varies from 10" to 96", the length of time it takes will vary.
When trailing edge extremity 31 of plank 3 reaches rollers 42, 43, such rollers are stopped if the gap sensor (not shown) detects that it is not the proper time to let such plank 3 fall below; in conjunction with plate 41, plank 3 is therefore held stationary over parallel spaced-apart bars 21 moving below. As soon as a proper positioning of parallel spaced-apart bars 21 moving below is detected, rollers 42, 43 are re-activated and plate 41 is removed so as to allow plank 41 to fall in between two adjacent spaced-apart bars (as outlined above, it is understood that rollers 42, 43 may not need to be stopped if proper positioning of parallel spaced-apart bars 21 moving below is detected at the moment trailing edge extremity 31 of plank 3 reaches rollers 42, 43). In terms of parts/minute, taking into account the time it takes the planks 3 to fall from plate 41 in between parallel spaced-apart bars 21, it means that plank feeder 4 can process about 80-180 parts/minutes (variations account for fact that planks 3 can be anywhere between 10"
and 96" in length) towards end matcher 2; this rates favourably against prior art plank feeders which typically cannot process more than 90 parts/minutes. As current end matchers 2 can process up to 180 parts/minutes, the resulting increase in ppm that the current embodiment of the plank feeder provides is useful. It must be noted that the previous ft/min and parts/min numbers are provided solely for exemplary purposes and should not be construed in any way as limiting the invention.

[0036] As can be understood from the description above, the efficiency of plank feeder 4 will depend on the translational speed at which rollers 42. 43 can position plank 3 over support 41. The efficiency of plank feeder 41 will also depend on the speed at which support 41 can be removed from under plank 3 and the height plank 3 has to travel before hitting end matcher 2; the closer top surface 41A is located over end-matcher 2 and the quicker support 41 can be removed, the more efficient plank feeder 4 will be.
In the current embodiment, support 41 is a single thin plate that can be slid horizontally between a support and a non-support position. It has been found that this is an efficient set-up as such single thin plate can be positioned closer over end matcher 2 and can activated quicker than already known trap-door set-ups. It is however possible, pursuant to the invention, to have other types of support 41.

[0037] Fig. 7 is an exemplary illustration of linear conveyor 1 conveying hardwood planks 3 towards plank feeder 4, more specifically towards rollers 42, 43. Only side wall 15, near which planks 3 are carried by conveying surface 11, is shown; the opposite side wall (not shown) is similar except for the fact that it can be moved towards/away side wall 15 so as to create a funnelling path forcing planks 3 towards side wall 15 as it is being carried by conveying surface 11 towards rollers 42, 43. Linear conveyor 1 may contain a pressure wheel 13 which exerts a downward pressure on wood plank 3 to locally increase the friction force between such plank 3 and conveying surface 11. Linear conveyor 1 may also contain a plank feed detecting wheel 12 for detecting relevant information about the planks 3 upstream of plank feeder 4 being carried by conveying surface 11.

[0038] The above description is meant to be exemplary only, and one skilled in the art will recognize that changes may be made to the embodiments described without departing from the scope of the invention disclosed. Still other modifications which fall within the scope of the present invention will be apparent to those skilled in the art, in light of a review of this disclosure, and such modifications are intended to fall within the appended claims.

Claims (18)

1. A wood plank feeder for transferring wood plank from a conveyor to transversely moving parallel spaced-apart bars and wherein the wood plank exits the conveyor in a direction substantially parallel to the spaced-apart bars, the wood plank feeder comprising:
a pair of rollers positioned downstream of the conveyor, at least one of the two rollers being rotationally driven by a power source, and a support positioned downstream of the pair of rollers and over the transversely moving parallel spaced-apart bars;
wherein the wood plank flowing through the pair of rollers is directed over the support.

2. The wood plank feeder as defined in claim 1, the wood plank feeder further comprising a plank position sensor for detecting a presence of a trailing edge extremity of the wood plank in between the pair of rollers, the plank position sensor being operationally linked to the at least one of the two rollers being rotationally driven by a power source at a rotational speed.

3. The wood plank feeder as defined in claim 2, wherein the plank position sensor causes the at least one of the two rollers being rotationally driven by a power source to reduce its rotational speed when the presence of a trailing edge extremity of the wood plank in between the pair of rollers is detected.

4.The wood plank feeder as defined in claim 1, wherein the pair of rollers are moveable with respect to one another.

5. The wood plank feeder as defined in claim 4, wherein the at least one of the two rollers being rotationally driven by a power source comprises a wood gripping surface and the pair of rollers are subjected to a biasing force acting against a movement of the pair of rollers away from one another.

6. The wood plank feeder as defined in claim 2, the wood plank feeder further comprising a bar gap sensor for detecting a position of at least one of the parallel spaced-apart bars vertically below the support, the bar gap sensor being operationally linked to the at least one of the two rollers being rotationally driven by a power source.

7. The wood plank feeder as defined in claim 6, wherein, when the presence of a trailing edge extremity of the wood plank in between the pair of rollers is detected, the bar gap sensor causes the at least one of the two rollers being rotationally driven by a power source to stop rotating when an unsatisfactory position of the at least one of the parallel spaced-apart bars vertically below the support is detected and then to resume rotating when a satisfactory position of the at least one of the parallel spaced-apart bars vertically below the support is detected.

8. The wood plank feeder as defined in claim 2, the wood plank feeder further comprising a bar gap sensor for detecting a position of at least one of the parallel spaced-apart bars vertically below the support, the bar gap sensor being operationally linked to the support.

9. The wood plank feeder as defined in claim 8, wherein, when the presence of a trailing edge extremity of the wood plank in between the pair of rollers is detected, the bar gap sensor causes the support to be removed from underneath the wood plank when a satisfactory position of the at least one of the parallel spaced-apart bars vertically below the support is detected.

10. The wood plank feeder as defined in claim 2, the wood plank feeder further comprising a bar gap sensor for detecting a position of at least one of the parallel spaced-apart bars vertically below the support, the bar gap sensor being operationally linked to the at least one of the two rollers being rotationally driven by a power source and being operationally linked to the support.

11. The wood plank feeder as defined in claim 10, wherein, when the presence of a trailing edge extremity of the wood plank in between the pair of rollers is detected, the bar gap sensor causes the at least one of the two rollers being rotationally driven by a power source to stop rotating when an unsatisfactory position of the at least one of the parallel spaced-apart bars vertically below the support is detected and, when a satisfactory position of the at least one of the parallel spaced-apart bars vertically below the support is detected, to cause the at least one of the two rollers being rotationally driven by a power source to resume rotating and to cause the support to be removed from underneath the wood plank.

12. The wood plank feeder as defined in claim 1, wherein the support is a horizontally displaceable plate.

13. The wood plank feeder as defined in claim 8, wherein the support is a horizontally displaceable plate and the bar gap sensor causes the horizontally displaceable plate to be removed from underneath the wood plank when a satisfactory position of the at least one of the parallel spaced-apart bars vertically below the horizontally displaceable plate is detected, after a presence of a trailing edge extremity of the wood plank in between the pair of rollers has been detected.

14. The wood plank feeder as defined in claim 10, wherein the support is a horizontally displaceable plate and the bar gap sensor, when a unsatisfactory position of the at least one of the parallel spaced-apart bars vertically below the horizontally displaceable plate is detected, causes the at least one of the two rollers being rotationally driven by a power source to stop rotating and, when a satisfactory position of the at least one of the parallel spaced-apart bars vertically below the horizontally displaceable plate is detected, to cause the at least one of the two rollers being rotationally driven by a power source to resume rotating and to cause the horizontally displaceable plate to be removed from underneath the wood plank.

15. A method for transferring wood plank from a conveyor to transversely moving parallel spaced-apart bars, the method comprising:
a. causing a movement of the wood plank from the conveyor, in a direction substantially parallel to the spaced-apart bars, over such moving parallel spaced-apart bars at a determined translational speed;

b. when the wood plank has reached a determined position over the moving parallel spaced-apart bars, reducing the determined translational speed of the wood plank;
c. determining a position of at least one of the moving parallel spaced-apart bars below the plank; and d. performing only one of the following 2 steps:
i. if the at least one moving parallel spaced-apart bars is in an unsatisfactory position, reducing the determined translational speed of the wood plank to zero and holding such wood plank in a stationary position until the at least one parallel spaced-apart bar is in a satisfactory position, then, when the at least one moving parallel spaced-apart bars is in a satisfactory position, resuming the movement of the wood plank and letting such wood plank fall between 2 transversely moving parallel spaced-apart bars;
ii. if the at least one moving parallel spaced-apart is in a satisfactory position, letting the wood plank fall between 2 transversely moving parallel spaced-apart bars.

16. The method of claim 15, wherein the step of causing a movement of the wood plank from the conveyor is performed by pinching the wood plank between two rollers, at least one of the two rollers being rotationally driven by a motor.

17. The method of claim 15, wherein the determined position of the wood plank is reached when a trailing edge extremity of such wood plank is located between the two rollers.

18. The method of claim 15, wherein the satisfactory position of the moving parallel spaced-apart bars is when a gap between adjacent moving parallel spaced-apart bars is positioned such that letting the wood plank, held over the moving parallel spaced-apart bars, will result in such wood plank falling between such adjacent moving parallel spaced-apart bars.