The invention relates to processing of wood in mills. More precisely, this invention pertains to a method and automatic apparatus for spacing boards.
It is common in sawmills to process a large number of individual boards of selected sizes for further sorting, turning, cutting or planning. Most of the times, the boards emerge from the mill in random order and must be presented separately and individually for proper processing (e.g. end trimmer or bin sorter). Therefore, there are different types of automatic devices that exist for loading, transferring and stacking boards. Examples of such devices are described in U.S. Pat. No. 4,869,360; U.S. Pat. No. 5,921,376; U.S. Pat. No. 5,353,272; U.S. Pat. No. 6,048,164; U.S. Pat. No. 6,238,174; U.S. Pat. No. 6,431,343; and U.S. Pat. No. 6,446,485.
Although useful, the devices known in the art do not address all the needs of the wood cutting industry. For improving their productivity, sawmills require faster devices that are versatile enough to operate at variable speeds, capable of varying the distance between the spaced apart boards, and also capable of spacing boards of different thickness and length. Furthermore, safety of some of those devices is a problematic as they can pitch boards in the air thereby posing serious risks to surrounding workers and equipment.
Therefore, it would be desirable to be provided with an apparatus for spacing boards that is automatic, that can operate at high speed, and that can be feed with boards of different thickness and length.
Features of the invention will be apparent from review of the disclosure, drawings and description of the invention below.
According to one aspect, the invention relates to an apparatus for spacing out boards. According to one embodiment, the apparatus comprises:
providing means for providing a flow of boards, the providing means having a providing end wherefrom the flow of boards is provided;
conveying means for conveying spaced out boards, the conveying means having a receiving end overlapping the providing end;
stopping means, the stopping means having a blocking position for retaining a board at the receiving end of the conveying means and preventing forward movement of said board on the conveying means, and a release position for freeing said retained board and allowing movement of the board on the conveying means;
vertical pushing means for applying a downwardly oriented force on a board retained at the receiving end of the conveyor means, said force increasing friction of the board on the conveying means and urging movement of the board on said conveying means; and
controlling means for coordinating an actuation of the vertical pushing means and movement of the stopping means to its release position.
According to one embodiment, the providing means comprises a powered conveyor for providing an uninterrupted flow of adjacent boards.
In one embodiment, the conveyor means preferably comprises a belt conveyor. The belt can be made of a material selected from a group consisting of rubber compounds, plastic compounds, silicone, urethane, and gum rubber
According to one embodiment, the receiving end of the conveying means is positioned above (e.g. about 1.5 mm to about 3.2 mm) the overlapping providing end of the providing means.
In another embodiment, the apparatus comprises at least two stopping means and at least two vertical pushing means. The at least two stopping means and at least two vertical pushing being positioned at opposite sides of the conveying means in order to contact distanced portions a board.
In yet a further embodiment, the stopping means comprises a pivotable finger positioned at the receiving end of the conveyor means. The pivotable finger alternatively pivots between a blocking position for contacting a front face of a board and a release position. The pivotable finger may be mounted on an axle positioned underneath a plane defined by a top surface of the receiving end overlapping the providing end. The pivotable finger may be actuated using air pressure, and it can pivots at a speed typically ranging between 0 and 400 times per minute or more.
In one embodiment, the vertical pushing means applies a temporal downwardly oriented force on a board retained at the receiving end of the conveyor means. The pushing means may comprise a pivotable arm positioned above a plane defined by a top surface of the receiving end overlapping the providing end. Such arm may comprise at least one board contacting wheel mounted at an end thereof. The pivotable arm may be actuated using air pressure and it can pivots at a speed typically ranging between 0 and 400 times per minute or more.
In a further embodiment, the apparatus further comprises antifriction means pivoting on an axle located underneath a plane defined by a top surface of the receiving end overlapping the providing end. The antifriction means pivots between a non-operating position and an operating position wherein it applies an upward pressure on a board retained at the receiving end of the conveyor means thereby decreasing friction of the retained board on the conveyor means.
In a one embodiment, the controlling means are operatively connected to the stopping means and the vertical pushing means such that actuation of the stopping means from its blocking position to its release position shortly precedes actuation of the vertical pushing means. The controlling means preferably comprises detection means for detecting presence or absence of a retained board at the receiving end of the conveyor means. The detection means may comprise an optical detector operatively connected to the stopping means.
According to another aspect, the invention relates to an apparatus for spacing out boards. According to one embodiment, the apparatus comprises
a chain conveyor for providing a flow of boards to be spaced out, said chain conveyor having a providing end wherefrom the flow of boards is provided;
a belt conveyor for conveying spaced out boards, said a belt conveyor having a receiving end overlapping the providing end of the chain conveyor;
at least two pivotable fingers positioned at substantially opposed extremities of the receiving end of the belt conveyor, said pivotable fingers alternatively pivoting between a blocking position for contacting a front face of a board and a release position;
at least two pivotable arms positioned above and at substantially opposed extremities of the receiving end of the belt conveyor, said pivotable arms being configured for applying a downwardly oriented force on a board retained at the receiving end of the belt conveyor, said force increasing friction of the board on the belt conveyor and urging movement of the board on said belt conveyor;
at least one optical detector for detecting presence or absence of a retained board at the receiving end of the belt conveyor; and
a signal processing unit operatively connected to said pivotable fingers, to said pivotable arms and to said optical detector, the signal processing unit coordinating actuation of the pivotable arms and coordinating movement of the pivotable fingers between said blocking and release positions.
In order that the invention may be readily understood, embodiments of the invention are illustrated by way of example in the accompanying drawings.
Further details of the invention and its advantages will be apparent from the detailed description included below.
In the following description of the embodiments, references to the accompanying drawings are by way of illustration of an example by which the invention may be practiced. It will be understood that other embodiments may be made without departing from the scope of the invention disclosed.
Now referring to
Accordingly, the apparatus 100 comprises providing means 114 for providing a flow of boards 102, the providing means having a providing end 116 wherefrom the flow of boards 102 is provided, as best shown on
The apparatus 100 further comprises conveying means 118 for conveying spaced out boards; the conveying means 118 having a receiving end 120 overlapping the providing end 116, as best shown on
The apparatus 100 further comprises stopping means 122. The stopping means 122 having a blocking position (see
The apparatus 100 further comprises vertical pushing means 124 for applying a downward temporal pressure on a board retained at the receiving end 120 of the conveying means 118, the pressure increasing friction of the board on the conveying means 118 and urging movement of the boards on the conveying means 118.
The apparatus 100 further comprises controlling means for coordinating an actuation of the vertical pushing means 124 and movement of the stopping means 122 to its release position.
The elements of the apparatus 100 will now be detailed according to one embodiment of the present invention.
In the embodiment shown on
In the embodiment shown in
The providing means 114 further comprise an optional chain guiding rail 138 whereon the chain 132 sits. The purpose of the chain guiding rail 138 is to guide the chain 132 along a predetermined path extending from the first end 110 of the apparatus 100 toward the delivery section 108. The guiding rail 138 is welded to the frame 126.
In the embodiment shown on
The apparatus 100 of the invention further comprises conveying means 118 for conveying spaced out boards 102. In the embodiment illustrated in
Preferably, the belt 142 is made of rubber. It can also be made of another a material such as plastic, silicone, urethane, gum rubber of any other material that one skilled in the art might see fit for this application.
Alternatively, the conveying means 118 may simply comprise a wheel having a friction surface such as rubber or the like and an inclined slope on which boards could slide away from the spacing section. In a further alternative embodiment, the conveying means 118 the wheel may consist of a sprocket wheel. The skilled addressee will appreciate that various other embodiments may be used for conveying means 118.
The stopping means 122 are located at the spacing section 106 of the apparatus 100. In the embodiment illustrated in
As best show in
In the illustrated embodiment, the pivotable finger 208 is a generally L-shaped member comprising a central bulging section 212, a generally crescent-shaped end 214 for limiting the range of movement of the pivotable finger 208 and an upwardly extending hooking tip 216. The bulging section 212 is operatively connected to a rotating axle 210. In the present embodiment, the rotating axle 210 is operatively connected to actuating means comprising a rotary pneumatic actuator 160 (
The pivotable finger 208 is further provided with a stop member 218 located within the crescent-shaped end 214, thereby limiting the rotational displacement of the pivotable finger 208. In the embodiment illustrated at
The skilled addressee will appreciate that the stopping means 122 may be any means capable of effectively retaining and releasing boards and that the invention is not limited to a pivotable finger. For instance, in another embodiment, the stopping means 122 comprise a tip moving vertically between a lower release position to an upper blocking position. Therefore, invention encompasses theses and additional stopping means.
The vertical pushing means 124 are also located at the spacing section 106 of the apparatus 100. In the embodiment illustrated in
The mounting portion 222 serves to pivot the arm 220 about an axle 226 and it is connected thereto by fixing means e.g. mounting brackets. The arm 220 is operatively connected to actuating means. In the illustrated embodiment, the actuating means comprises a double acting rotary pneumatic actuator 162 (see
The angled-down portion 224 of the pivotable arm 220 comprises two optional board contacting wheels 228, 230 mounted at the end thereof. The contacting wheels are useful for easing movement of the pivotable arm 220 as it moves upwardly and downwardly with the passing boards. The board contacting wheels 228, 230 are particularly useful for thicker boards having a thickness of 5 cm (2″) and above (e.g. 3″×3″ and 4″×4″ boards).
The skilled addressee will appreciate that the vertical pushing means 124 may be any means capable of effectively applying a downward temporal pressure on a board 102 retained at the receiving end 120 of the conveyor means 118. For instance, in another embodiment, the vertical pushing means 124 comprise a rotating friction wheel for pressing of a board retained at the receiving end 120 of the conveying means 118 and for urging movement or increasing moving speed of such board. In other embodiment, the vertical pushing means may comprise a pneumatic or hydraulic cylinder. Therefore, invention encompasses these and additional vertical pushing means.
As indicated herein before, the apparatus 100 further comprises controlling means for coordinating an actuation of the vertical pushing means 124 and movement of the stopping means 122 to its release position. In the present embodiment, the controlling means comprises detection means for detecting the presence or absence of a board retained at the receiving end 120 of the conveying means 118. In the present embodiment, the detection means comprises an optical detector 164 (see
Although preferred to achieve high speed, the detection means are somewhat facultative since manual activation of the stopping means and vertical pushing means is conceivable. It is also conceivable to preprogram actuation of the pivotable finger 208 and pivotable arm 220 according to an automatic switching scheme programmed depending on various parameters such as the size of the board, the speed of the chain 132, the speed of the belt 142, etc.
The controlling means may comprise a signal processing unit such as a microcontroller operatively connected to one or more optical detectors 164, the vertical pushing means 124, and the stopping means 122. The signal processing unit may be part of a computer assembly and may also be operatively connected to the conveyor and the belt for adjusting the speed thereof. This setup would provide ease of use to the apparatus and would allow for the sequence of operations to be completely preprogrammed and fully automated.
Additional explanations regarding the basic principles of the functioning of the invention is given hereinafter with particular reference to
In the illustrated embodiment, the providing end of the providing means (i.e. the chain 132) is located on a first horizontal plane 600 while the receiving end of the conveying means (i.e. the belt 142) is located on a second, higher horizontal plane 602. Since the belt 142 of conveying means and the chain 132 of the providing means overlaps, a retained board is positioned partly over the chain 132 and partly over the belt 142, that retained board is urged to move forwardly and upwardly fully onto the belt 142 by its momentum as well as by a force exerted by following boards Consequently, the bottom surface 604 of the retained board leaves the first horizontal plane 600 to fully contact the belt 142 located at the second horizontal plane 602. Best results have been observed when the overlap of the belt 142 and the chain 132 is about 30 to 45 millimeters. The apparatus could be configured to change or adjust this overlap if so desired.
The vertical pushing means 124 provides a downward temporal pressure on the retained board. This downward pressure allows the retained board to exert sufficient downward force on the belt 142 prevent slipping of the board once released to urge movement of the released board onto the belt 142. When a board is retained at the providing end by the stopping means 122, the actuating means 162 of the pivoting arm 220 are an idle mode and the pivoting arm 220 is solely subjected to its own weight. The contacting wheels 228, 230 contact moving boards advancing toward the stopping means 122 such that the pivotable arm 220 moves upwardly and downwardly according to the thickness of boards moving underneath.
In another embodiment, the apparatus 100 further comprises optional antifriction means 150. In the illustrated embodiment, the antifriction means 150 comprises a pivotable banana-shaped member 152 mounted below the plane 600 formed by a top surface of the providing end 116. The member 152 comprises a mounting end 154 and a contacting end 156.
The mounting end 154 serves to pivot the pivotable member 152 about an axle between a non-operating position and an operating position. A stop member 159 limits the movement of the pivotable member 152. The non-operating position is defined as a position wherein the contacting end 156 of the antifriction means 150 does not contact a board 250 retained at the receiving end 120 of the conveying means 118, while the operating position is defined as a position wherein the contacting end 156 of the antifriction means 150 applies an upward pressure on a board 250 retained at the receiving end 120 of the conveying means 118 in order to lessen friction of the board 250 on the conveying means 118. The pivotable member 152 is operatively connected to actuating means. In the illustrated embodiment, the actuating means comprises a rotary pneumatic actuator 168. The main purpose of the antifriction means 150 is to release the pressure applied on the belt 142 by a retained board 250 while the belt 142 is still running. This help preventing premature tearing of the belt. Such functionality is particularly useful when loading of boards 102 on the receiving section 104 is paused or stopped, or when boards moving on the chain 132 towards the spacing section 106 of the apparatus 100 are improperly spaced or aligned.
The embodiment illustrated at
Having described the components of the apparatus 100 according to different embodiments the invention, the operating sequence of a preferred embodiment will now be described in details with reference to
At the beginning of the process the pivotable finger 208 is in the blocking position. The chain 132 of the providing means 114 is moving a continuous flow of boards 102 towards the spacing section 106 at a first speed. The belt 142 of the conveying means 118 has a displacement speed greater than that the chain 132.
As shown in
The optical detector 164 detects the presence of the retained board 250 abutting the pivotable finger 208. The actuating means 160 of the pivotable finger 208 being operatively coupled to the controlling means, it pivots the pivotable finger 208 such that its hooking tip 216 moves downwardly in the release position and releases the retained board 250, as shown in
Shortly thereafter, the controlling means provide an impulsion of pressure to the actuating means 162 operating the vertical pushing means 124, resulting in a downward pressure being applied by the pivotable arm 220 for a very short period of time. Best results have been obtained when the pivotable arm applies a pressure ranging between 10 and 90 PSI for about 40 ms. The pressure being applied by the pivotable arm 220 on the upper surface 606 of the retained board 250 increase the friction of its lower surface 604 with the belt 142 underneath. This increase of friction urges the newly unblocked retained board 250 to engage the belt 142 further and move thereon towards the delivery section 108 of the apparatus 100 (
Upon detection of the empty space 400, the pivotable finger 208 is actuated back from its release position to its blocking position, as shown in
One can readily appreciate that the whole process and the repeated actuation of the pivotable finger 208 and pivotable arm 220 will result in a continuous and regular flow of evenly spaced boards.
Referring now to
As seen therein, the apparatus of the invention thus possesses numerous advantages. It has a simple and yet, extremely effective design. It offers great performance and it is highly versatile since it can readily process board of different length (from 4 feet to 24 feet (1.22 m to 7.32 m), e.g. 4, 6, 8, 10, 12, 16, 20, 24 feet), different thickness (½ inch to 4 inches (1.27 cm to 5 cm), e.g. 1, 2, 3, 4 inches), and different width (1 inch to 12 inches (2.5 cm to 30 cm), e.g. 2, 4, 6, 8, 10, 12 inches). It is also ideal for high speed operation (e.g. 200, 250, 300, 400 pieces per minute, and possibly more), both at the green and the dry end of a mill. It can also be customized to specific needs (e.g. integrated to planermill system).
While the apparatus described herein is intended for spacing boards, the skilled addressee will appreciate that this apparatus could also be used for spacing different objects such as sticks. The apparatus of the invention can also very useful in the flooring industries since it does not puncture or leave marks on boards, a highly desired quality for preserving esthetic of hardwood flooring boards.
Although the above description relates to a specific preferred embodiment as presently contemplated by the inventor, it will be understood that the invention in its broad aspect includes mechanical and functional equivalents of the elements described herein.
The present application claims priority to U.S. provisional application No. 60/948,603 filed on Jul. 9, 2007, the content of which is incorporated herein by reference.
Number | Date | Country | |
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60948603 | Jul 2007 | US |