Method for densifying a fibrous mat
10046478 ยท 2018-08-14
Assignee
Inventors
- James Michael White (Meridian, MS, US)
- Roy Daniel Seale (Starkville, MS, US)
- Don Roberts Clark (Witts Springs, AR, US)
Cpc classification
B30B5/00
PERFORMING OPERATIONS; TRANSPORTING
International classification
B30B5/00
PERFORMING OPERATIONS; TRANSPORTING
B30B13/00
PERFORMING OPERATIONS; TRANSPORTING
Abstract
A method for densifying a fibrous mat, such as scrim, to achieve a uniform mat density, including a set of parallel bars each having a row of pins extending downward therefrom which can engage the mat fibers, a plurality of shafts along which the bars slide so as to maintain the bars parallel, a plurality of extendable accordion linkages connecting the set of bars, and a linear positioning assembly having a reciprocating drive mechanism coupled to one of the bars which can move the bars in response to an actuation signal. As the drive mechanism retracts the bar to which it is coupled the spacing between the rows of bars is decreased uniformly and the rows of pins draw the fibers together and compress them uniformly across the width of the mat.
Claims
1. A method for increasing the density of a fibrous mat, the mat fibers having a face and a grain defined as a direction of the face of the mat, the method comprising: (a) inserting a plurality of rows of pins in the mat, the pins being maintained in spaced apart relationships by a plurality of bars, each bar having a plurality of spaced apart pins associated therewith and extending downward therefrom, each bar being associated with an accordion linkage adapted to maintain each row of elongated bars in a generally parallel relationship to each other and permitting the distance between the bars to expand or contract proportionately so that a spacing between the rows of bars is equal while an overall spacing between adjacent bars increases or decreases; and, (b) moving the rows of pins so that the spacing between the rows decreases by the same amount so as to compress the mat fibers between the rows of pins uniformly across the grain of the mat to compress the mat in a direction across the face of the mat and generally uniformly along the length of the mat so as to obtain a compressed mat having a substantially uniform density.
2. The method of claim 1, further comprising a step (c) removing the pins from the mat so as to be insertable in another mat.
3. The method of claim 1, wherein each row of pins is associated with and extends downward from a movable bar, each bar being associated with a drive member adapted to move the bar in a linear direction.
4. The method of claim 3, wherein each bar is associated with at least one reciprocatingly extendable and retractable accordion linkage arranged generally parallel to each other and generally perpendicular to the bar, each accordion linkage being associated with at least one point on each bar, the at least one accordion linkage being adapted to maintain each of the bars in a generally parallel relationship to each other and permitting the distance between the bars to expand or contract proportionately so that the spacing between the bars is equal while the overall spacing between adjacent bars increases or decreases.
5. The method of claim 1, further comprising a step of weighing the mat using at least one weight detection device to obtain weight data.
6. The method of claim 5, further comprising a step of scanning the mat with at least one detection device adapted to detect the surface and edges of the mat so to obtain square footage data of the mat.
7. The method of claim 6, further comprising a step of determining from the weight and square footage data a densification value indicating how much the mat is to be compressed.
8. The method of claim 7, further comprising a step of signaling a drive member in mechanical communication with the rows of pins a distance based on the densification value to cause the rows of pins to be moved so as to compress the mat fibers a predetermined amount.
9. The method of claim 2, further comprising a step of stripping at least one of the pins of debris that may have clung to the pin.
10. The method of claim 9, wherein the stripping is achieved by providing a stripper subassembly comprising a stripper subassembly frame; a plurality of stripper members associated with the stripper subassembly frame and aligned with the rows of pins; a plurality of gaps defined in the stripper members, a pin being insertable into and removable from a gap; and, at least one stripper subassembly actuator for raising and lowering the stripper subassembly frame and stripper members with respect to the rows of pins such that the stripper members are proximate to the pins and strip the pins of debris when the pins pass through the gaps.
11. The method of claim 10, wherein each stripper member comprises a pair of L-shaped plates, each pair comprising a first elongated generally L-shaped plate and a second elongated generally L-shaped plate, the first and second plates being mounted to the stripper subassembly frame in pairs with the vertical segment of one first L-shaped plate being parallel and adjacent to the vertical segment of one second L-shaped plate so as to form a gap between the pair of L-shaped plates such that a row of pins can be inserted and removed from the gap and the pair of L-shaped plates being spaced so as to scrape extraneous matter from the pins when the pins pass into the gap.
12. The method of claim 10, wherein each stripper member comprises a generally flat horizontal plate mounted to the stripper subassembly frame, the plate having a plurality of holes defined therein, each hole being sized to accommodate a pin such that extraneous matter can be scraped by the plate edge forming the hole when a pin is passed through the hole.
13. The method of claim 2, further comprising a step of moving the compressed mat toward a location for stacking a plurality of compressed mats.
14. A method for increasing the density of a fibrous mat, the mat fibers having a face, surface and edges, and a grain defined as a direction of the face of the mat, the method comprising: scanning the mat with at least one detection device adapted to detect the surface and edges of the mat so to obtain square footage data of the mat; determining from a weight of the mat and the square footage data a densification value indicating how much the mat is to be compressed; inserting a plurality of rows of pins in the mat, wherein each row of pins is associated with and extends downward from a movable bar, each bar being associated with a drive member adapted to move the bar in a linear direction, wherein each bar is associated with at least one reciprocatingly extendable and retractable accordion linkage arranged generally parallel to each other and generally perpendicular to the bar, each accordion linkage being associated with at least one point on each bar, the at least one accordion linkage being adapted to maintain each of the bars in a generally parallel relationship to each other and permitting the distance between the bars to expand or contract proportionately so that a spacing between the bars is equal while an overall spacing between adjacent bars increases or decreases; signaling at least one drive member in mechanical communication with each bar, the at least one drive member adapted to move the bars with the row of pins associated with each bar; moving the rows of pins so that the spacing between the rows decreases by the same amount so as to compress the mat fibers between the rows of pins uniformly across the grain of the mat to compress the mat in a direction across the face of the mat and generally uniformly along the length of the mat so as to obtain a compressed mat having a uniform density; and, removing the pins from the mat and resetting the rows of pins so as to be insertable in another mat.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
(1) The invention is illustrated in the drawings in which like reference characters designate the same or similar parts throughout the figures of which:
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DETAILED DESCRIPTION
(17) Overall Apparatus
(18) Steam press scrim lumber (SPSL) is composed of processed mats of fibers obtained by crushing and processing logs of generally small diameters. A conventional mat 1 (see
(19) The main assemblies include a main frame, carriage frame assembly, and densifier assembly. The densifier assembly includes a densifying subassembly and a stripper subassembly.
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(21) Main Frame
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(23) It is to be understood that in the present disclosure reference to air cylinders, pistons, actuators or other linear motion-inducing devices is intended to include other drive mechanisms, such as, but not limited to, pneumatic, hydraulic, belt, ball screw, chain drive, and the like. Such devices are also intended to include (if not specifically mentioned) associated valves, actuators, motors, PLC communication connections and the like normally associated with such devices for ordinary functioning. It is also to be understood that reference to a particular number of such devices is intended to include at least that number and the scope of the present disclosure include additional (or possibly fewer) units, unless otherwise specifically excluded.
(24) The main frame 100 is divided into two main areas, a densification area 126 and a mat gathering area 127 (see
(25) Carriage Frame Assembly
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(27) The carriage frame assembly 21 has mounted to it a pair of vertical raising and lowering actuators 95 and associated mechanism for raising and lowering the densifier assembly 20 in response to an electronic signal from the processor 140 (discussed in more detail hereinbelow). The carriage frame assembly 21 has also mounted to it a pair of actuators 66 and associated air valves for raising and lowering a stripper assembly 21. Thus, the densifier assembly 20 is raised and lowered with respect to the carriage frame assembly 21 so that a mat 1 can be positioned under the densifier assembly 20. The stripper subassembly 60 The carriage frame assembly can move horizontally on the main frame 100.
(28) Densifier Assembly
(29) The densifier assembly 20 consists generally of a densifying subassembly 19 and a linear stripper subassembly 60.
(30) Densifying Subassembly
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(32) The densifying subassembly 11 also includes a number of elongated passive densifying bars 22 (see
(33) The densifying subassembly 20 has at least one, and, in one exemplary embodiment, a plurality of extensible accordion linkages (also known as extensible scissors linkages) 42 spaced across the bars 22, 28, 30. In one embodiment the accordion linkages 42 are mounted on top of the bars 22, 28, 30. Each accordion linkage 42 is attached via at least one pin 44 to each bar 22, 28, 30. The accordion linkages 42 function to maintain the bars 22, 28, 30 in a generally equal spaced relationship; in other words, as the passive and drive bars 22, 30 are moved along the shafts 26 the accordion linkages 42 maintain the same relative distance between each bar 22, 30.
(34) The densifying subassembly 11 includes at least one (two are shown in the drawings) stop assemblies 15 (see
(35) The passive and drive bars 22, 30 are moved along the shafts 26 by means of a linear positioning actuator 50 (see
(36) Stripper Subassembly
(37) The apparatus 10 may also include a stripper assembly 60 (see
(38) In an alternative embodiment, rather than being L-shaped plates, the strippers may be generally flat elongated plates which have holes or openings in which the pins 40 may be inserted or removed. The holes are sized to be close in diameter to the diameter of the pins 40 so that when the pins are removed from the densified mat the pins 40 pass through the holes and the edge of the hole scrapes extraneous matter (e.g., fibers and resin) from the pins 40. Alternatively, other configurations of stripper devices can be used, such as doctor blades, spring mounted flexible pieces of materials (e.g., metal), brushes, scrapers or the like.
(39) The stripper subassembly 60 can be vertically raised and lowered and guided by vertically mounted shafts 65 and bearings which are attached to the top of the carriage frame assembly rails 86, 88 and driven by a pair of actuators 66 mounted on the carriage frame assembly 21.
(40) As shown in
(41) During the densification process mat fibers may stick to the pins 40. The stripper subassembly helps to remove mat fibers from the pins 40 when the pins 40 are removed from a densified mat 9. When the pins 40 are withdrawn from a mat they pass through the stripper surfaces 62, which scrape off the fibers from the pins 40. The densifying subassembly 11 and stripper subassembly 60 can be raised and lowered independently of each other. The stripper subassembly 60 is mounted on the carriage frame assembly 21 and the densifying subassembly 11 is mounted above the stripper subassembly 60 on the carriage frame assembly 21.
(42) The relative movement of the assemblies and subassemblies with respect to the main frame 100 is described as follows. The carriage frame assembly 21 itself can move horizontally on the main frame 100. The densifier assembly 20 can be raised and lowered with respect to the carriage frame assembly 21 so that a mat 1 can be positioned under the densifier assembly 20. The stripper subassembly 60 can be raised and lowered independently of the densifying subassembly 11 so that the pins 40 can be stripped of extraneous material.
(43) Measuring Sensors and Logic Control
(44) An infeed conveyor assembly 128 (see
(45) A programmable logic controller (PLC) 140 (not shown) is in electronic communication with the linear positioning drive motor 58, densifier assembly vertical positioning cylinders 95, the linear positioning assembly drive motor(s) 58, the stripper subassembly actuators 66, the carriage drive motors 116, and/or various other components. The PLC 140 is also in communication with the weight sensor 130 and the surface area detector 132. Preferably, the PLC 140 includes a user interface control panel 142 (not shown) for programming and operating the PLC 140.
(46) Exemplary Method
(47) One exemplary method of densifying a mat 1 using the apparatus 10 of the present disclosure is now described, with reference to the flow diagram shown in
(48) The mat 1 is introduced by the infeed belt 129 and is weighed by the weight sensor 130 and scanned (for surface area) by the surface area detector 132. From this information the PLC 140 calculates the amount of densification needed to achieve the desired mat density. The PLC 140 determines the distance the linear positioning screw 54 must travel and the distance the drive bar 30 must travel to compress the mat 1.
(49) The mat 1 is fed to the densification area 127 underneath the densifier assembly 20 by the introduction conveyor 128. The mat 1 is oriented on end with the fibers 2 being in a direction generally parallel to the bars 22. The mat 1 may have variable fiber density across the mat prior to densification, such as lower fiber density areas 7 and higher fiber density areas 8. The densifier assembly 20 is initially configured so that the distance between the drive bar 30 and the static bar 28 is roughly the width W of the mat 1. The densifier assembly 20 is raised and lowered by the vertical actuators 95 so that the pins 40 are pushed into or removed from the fibers 2.
(50) The linear positioning actuator 54 is actuated by the PLC 140 and the drive bar 30 is drawn toward the stop block. The passive bars 22 move simultaneously, with the accordion linkages 42 maintaining the same relative spacing Sp between the bars 22 as the distance between the bars decreases. The pins 40 push and compress the individual fibers (or bundles of fibers) together uniformly.
(51) One feature of the presently described apparatus and method is that the result of having all the pins 40 on all the passive bars 22 and drive bar 30 moving the same proportionate distance at the same time is that substantially the entire mat 1 (from the front edge 4 to the rear edge 6) is compressed by the same amount. Thus, the density of the densified mat 90 is now essentially uniform across the width W of the mat. This is in contrast to prior densification apparatus, which typically sandwich the mat between two external plates which drive the front edge toward the rear edge.
(52) After the mat 1 (now identified as densified mat 9) is compressed to the desired width, the carriage frame assembly 21, with densifier assembly 20 (and a mat 9 with the pins 40 still inserted therein), rolls on the main frame side rails 106, 108 in response to actuation of the main frame side rail pistons 114 and away from the densification area 127 and onto the exit conveyor 120. The stripper subassembly 60 is raised just prior to raising the pins 40. The densifier assembly 20 is raised by the actuators 95 and the pins 40 are removed from the mat fibers 2. The carriage frame assembly 21 is moved horizontally back to the densification area 126 for processing of the next mat 1. The densified mat 9 is conveyed toward the back stop 118 which has a gathering area 127 at the end of the conveyor 120. Densified mats 9 are crowded together and accumulated in this gathering area 127. These sets of mats 9 can be further processed, such as cut and stacked. The process is repeated with the next mat 1 being fed into the densification area 126.
(53) The following describes one nonlimiting example of the method described above using an example of measurements and calculations to illustrate the densification determination. The surface area detector 132 scans the surface area of the mat 1. The square footage determines the starting width of the mat 1. The PLC 140 actuates the linear positioning actuator 50 and sets the initial spread of the pins 40 so that all the rows of pins 40 are in the fibers 2. The PLC 140 is programmed and preset for a given mat width or density.
(54) A 30 inch wide by 9 foot long mat (22.5 sq ft) may weigh about 65 lbs. The PLC 140 calculates the starting density from these numbers as being 3.0 lb/sq. ft. A desired end density, e.g., 3.4 lb/sq. ft, is programmed into the PLC 140. Accordingly, the surface area needs to be compressed from 22.5 sq. ft down to 19.1 sq. ft to achieve this density. The width W needs to be compressed 4.5 inches, i.e., from 30 inches wide to 25.5 inches wide. The PLC 140 actuates the linear positioning actuator 50 to move the drive bar 4.5 inches. The accordion linkage 42 retracts and pins 40 drive and compress the fibers 2 substantially evenly across the mat 1 to achieve the desired width and thus the desired density. It is to be understood that compression, while occurring substantially evenly, may still result in areas of small density variation across the width of the mat.
(55) A feature of the presently described densification method and apparatus is that the densified mat 9 stays densified after the pin force is released. If the mat had been compressed only by squeezing the front and rear mat edges 4, 6 toward each other, the mat 9 would tend to decompress because it was not compressed uniformly.
(56) The densified mat 9 formed by the apparatus and method of the present disclosure has a more uniform density and moisture content across the width W of the mat than has been achievable by other known techniques. The density of the mat to be formed by the apparatus and method described herein can be selected by the apparatus operator. The density variation can be
(57) The apparatus and method of the present disclosure can be adapted for use with materials other than crushed wood mats and the densifier assembly can be used to increase the density of any of a variety of materials which can accommodate the pins 40. The densifier assembly 20 can be adapted to have the pins 40 be marking fingers and used to create a set of rows of marks across a mat or sheet of material. Alternatively, rather than pins, lasers, cutters or drill bits can be substituted so that a set of uniform and controllable width rows of holes can be created in a sheet of material, such as steel, by having the hole-creating devices lowered onto the sheet of material from above. The apparatus 10 can be adapted for creating a uniform density of large foam or cotton particles in creating mattresses or other articles requiring a uniform density of material and where the pins 40 can be inserted into and removed from the material to be densified.
(58) Although only a few exemplary embodiments of this invention have been described in detail above, those skilled in the art will readily appreciate that many modifications are possible in the exemplary embodiments without materially departing from the novel teachings and advantages of this invention. Accordingly, all such modifications are intended to be included within the scope of this invention as defined in the following claims.
(59) Unless otherwise expressly stated, it is in no way intended that any method set forth herein be construed as requiring that its steps be performed in a specific order. Accordingly, where a method claim does not actually recite an order to be followed by its steps or it is not otherwise specifically stated in the claims or descriptions that the steps are to be limited to a specific order, it is no way intended that an order be inferred, in any respect.
(60) As used in the specification and the appended claims, the singular forms a, an and the include plural referents unless the context clearly dictates otherwise. Ranges may be expressed herein as from about one particular value, and/or to about another particular value. When such a range is expressed, another embodiment includes from the one particular value and/or to the other particular value. Similarly, when values are expressed as approximations, by use of the antecedent about, it will be understood that the particular value forms another embodiment. It will be further understood that the endpoints of each of the ranges are significant both in relation to the other endpoint, and independently of the other endpoint.
(61) Optional or optionally means that the subsequently described event or circumstance may or may not occur, and that the description includes instances where said event or circumstance occurs and instances where it does not.
(62) The headings of various sections are used for convenience only and are not intended to limit the scope of the present disclosure.
(63) Throughout the description and claims of this specification, the word comprise and variations of the word, such as comprising and comprises, means including but not limited to, and is not intended to exclude, for example, other additives, components, integers or steps. Exemplary means an example of and is not intended to convey an indication of a preferred or ideal embodiment. Such as is not used in a restrictive sense, but for explanatory purposes.
(64) Disclosed are components that can be used to perform the disclosed methods, equipment and systems. These and other components are disclosed herein, and it is understood that when combinations, subsets, interactions, groups, etc., of these components are disclosed that while specific reference of each various individual and collective combinations and permutation of these may not be explicitly disclosed, each is specifically contemplated and described herein, for all methods, equipment and systems. This applies to all aspects of this application including, but not limited to, steps in disclosed methods. Thus, if there are a variety of additional steps that can be performed it is understood that each of these additional steps can be performed with any specific embodiment or combination of embodiments of the disclosed methods.
(65) It will be apparent to those skilled in the art that various modifications and variations can be made without departing from the scope or spirit. Other embodiments will be apparent to those skilled in the art from consideration of the specification and practice disclosed herein. It is intended that the specification and examples be considered as exemplary only, with a true scope and spirit being indicated by the following inventive concepts.
(66) It should further be noted that any patents, applications and publications referred to herein are incorporated by reference in their entirety.