Patent Application
20190276979
Industrial laundry applications require the processing of large numbers of flatwork textile articles. At various points in the process, the textile articles are washed and dried before they are laid flat and ironed. The steps of laying the articles flat and feeding them to be ironed are accomplished by a spreader/feeder. Spreader/feeders operate by receiving the corners of one edge of a textile article, spreading those corners apart so that the edge of the textile is pulled flat, and laying the textile on a roller or conveyer (also referred to as a feed table) to feed the textile to a downstream ironer.
Because a given spreader/feeder may receive textile articles of different sizes, each spreader/feeder must be able to spread the received textile article the appropriate length. If the opposing corners of a textile are not spread far enough apart, the textile will not lay flat on the feeder. If the opposing corners are spread too far, unnecessary stress is placed on the textile.
The differing natures of the textiles being spread presents a particular problem for the spreader/feeder. Indeed, each textile received by the spreader/feeder will have unique characteristics that affect the size of the textile and, thus, the spreading process. One reason for the variety of sizes between different textiles is moisture retention. Many items, when processed at the spreader/feeder, are wet—often with 30-40% moisture retention—whereas other items are completely dry. Two textiles from the same manufacturer, or even the same production lot, may be unequal in size due to their moisture retention. Furthermore, different textiles have often undergone differing numbers of laundered cycles, have differing exposure to use, abuse, and mending or repair, and are fed to the spreader/feeder in different ways. Not to mention that different textiles are made from a wide scope of materials including T120-600TC, 100% cotton, 60/40 cotton/poly blend, or poly-spun filament, each of which may be sourced from different manufacturers and countries with differing quality control standards. The net result is that the spread force applied to one textile may be sufficient to pull the textile flat, while the same force applied to another textile—having been processed more times, having different moisture retention, or made from a different material—will cause the textile to rip.
Accordingly, there exists a need in the art for detecting the length of a given textile to ensure that the textile is smoothly transferred from the spread mechanism to the feed table without improperly stretching the textile.
This disclosure is generally related to an apparatus and method for detecting the length of a received textile's leading edge and using that length to spread the textile substantially flat without improperly stretching the textile. According to an aspect, a textile spreader apparatus, comprises a first spread carriage and a second spread carriage, each configured to respectively receive opposing corners of a leading edge of a textile and to respectively convey the opposing corners in substantially opposing directions toward an extended position, such that the leading edge of the textile travels along a predetermined path; a catch arranged in the predetermined path of the leading edge, such that the catch intercepts the leading edge; and a sensor configured to detect when the catch intercepts the leading edge, wherein the catch is configured to retract from the path of the leading edge upon the sensor detecting a pressure applied to the leading edge, exceeding a threshold, wherein the threshold is reduced as the first spread carriage and the second spread carriage convey the opposing corners toward the extended position.
In another aspect, a textile spreader apparatus comprises a first spread carriage and a second spread carriage, each configured to respectively receive opposing corners of a leading edge of a textile and to respectively convey the opposing corners in substantially opposing directions, such that the leading edge of the textile travels along a predetermined path; a catch arranged in the predetermined path of the leading edge such that the catch intercepts the leading edge; a sensor configured to detect when the catch intercepts the leading edge; and a controller configured to determine, once the catch intercepts the leading edge, based on the position of at least one of the first spread carriage or the second spread carriage, an extended position, wherein the first and second spread carriages, when respectively positioned at the extended position, are spaced apart substantially the length of the leading edge.
In another aspect, a method for determining the length of a leading edge of a textile, comprises the steps of: providing a textile spreader apparatus comprising a first spread carriage and a second spread carriage, each configured to move between an initial position and an extended position; grasping a pair of opposing corners of a leading edge of a textile with the first and second spread carriages, wherein each of the first and second spread carriages respectively grasps one of the opposing corners such that a portion of a leading edge of the textile is held slack about a catch; conveying, with the first spread carriage and second spread carriage, the opposing corners in substantially opposing directions such that the leading edge travels along a predetermined path such that the catch, arranged in the predetermined path, intercepts the leading edge; detecting, with a sensor, when the catch intercepts the leading edge; and determining, once the catch intercepts the leading edge, based on the position of at least one of the first spread carriage or the second spread carriage, an extended position, wherein the first and second spread carriages, when respectively positioned at the extended position, are spaced apart substantially the length of the leading edge.
Referring to the figures, a front view of a spreader/feeder 10 is shown in
Each spread carriage 16, 18 may be configured to move in substantially opposing directions between an initial position and an extended position. In the initial position, the spread carriages 16, 18 may be disposed adjacent one another, while in the extended position the spread carriages may be spread apart. Stated differently, in the initial position, the spread carriages 16, 18 will be a first length apart and in the extended position the spread carriages 16, 18 will be a second length apart, the second length being greater than the first length. As used in this disclosure, the initial position may be a reference point, used by at least one calculation, to calculate the length of the leading edge of textile 20. The initial point may, for example, be the point at which the spread carriages 16, 18 receive the opposing corners of the leading edge of textile 20. The extended position is the point at which the leading edge of the textile is fully extended—i.e., the spread carriages are spread apart substantially the length of the leading edge, such that the textile hangs from the spread carriages in a substantially flat matter to permit textile 20 to transition flatly to the feed table. It should be understood that, because any given textile 20 received by spreader/feeder 10 may have a different or uniquely sized leading edge, the extended position will vary for a given textile 20. Spreader/feeder 10 is thus configured to determine the location of extended position for a given received textile 20, using either a calculation or a look-up table, as will be described below.
The spreader/feeder 10 may include a controller 14 configured to perform the various tasks described in this disclosure. For example, the controller 14 may be configured to control the motion of the spread carriages 16, 18, to track or receive the location of spread carriages 16, 18, to monitor and/or control the pressure sensor 38 (
In one embodiment, spread carriages 16, 18 may each be conducted along a track by a servo (electric or pneumatic) or any other type of actuator suitable for conducting each spread carriage 16, 18 along the track, as shown in
As mentioned above, spread carriages 16, 18 are conducted in substantially opposing directions. Here, “substantially opposing directions” means that the spread carriages 16, 18 move apart from each other in at least one dimension, such that the leading edge 24 of textile 20 is spread flat. Indeed, in addition to moving apart from each other in one dimension, spread carriages 16, 18 may move in any other dimension as long as the final position of leading edge 24 is substantially flat. For example, in addition to moving outward, both spread carriages 16, 18 may move upward. Of course, the directions that spread carriages 16, 18 move may have some effect on the methods of calculating the extended position and thus must be factored into the equations or look-up tables described below, as necessary.
Again, the spread carriages 16, 18 are configured to pull the leading edge of textile 20 flat. “Textile article” or “textile,” as used in this disclosure may refer to any textile flatwork article, such as, but not limited to, bed sheets or tablecloths. Further, while rectangular textile articles are depicted in the figures, it should be understood that the method described may be used to determine the length of any leading edge 24 of a textile, regardless of the number of sides the textile includes.
Further, as used in this disclosure, “substantially flat” requires only that the leading edge be flat enough that the textile 20 may be transferred to the feed table in a manner suitable to be processed by the remaining downstream devices/workers, e.g., an ironer. The leading edge may be “substantially flat” and still follow a gentle arc. Further, when the spread carriages are in the extended position, and thus are positioned substantially the length of the leading edge 24, it should be understood that this length does not include the portion of the leading edge grasped by the spread carriages 16, 18 (e.g., the opposing corners of the leading edge).
Referring again to
A catch 26 may be arranged between and/or below (with respect to the surface upon which device 12 rests) spread carriages 16, 18 and positioned so that catch 26 is arranged within the substantially parabolic shape formed by leading edge 24. As the spread carriages 16, 18 move in substantially opposing directions, the leading edge 24 of the textile 20 will travel along a predetermined path until it is held in a substantially flat position, as shown in
Because of the placement of catch 26, leading edge 24 will be intercepted by the catch 26 as a result of the spread sequence, as shown in
The interception of the leading edge 24 by the catch 26 may be detected by one or more sensors. For example, the interception of leading edge 24 may be detected by a pressure sensor 38 (shown, for example, in
Intercepting the leading edge 24 may include the step of pulling the leading edge into at least one flat length about the catch 26, forming, for example, a V-shape about vertex V, as shown in
It is conceivable to calculate the extended position without first pulling the leading edge 24 into the at least one flat length. For example, the pressure sensor 38 may be configured to calculate the slightest pressure (e.g., any determinable nonzero pressure) applied to the catch 26, or an optical sensor may simply detect when the leading edge 24 contacts the catch 26, and the position of at least one of the spread carriages 16, 18 may be recorded at this point; however, failing to pull the leading edge 24 into at least one flat length may result in a loss of accuracy, as the amount of the leading edge held slack is not readily determinable and may vary across textiles with differently sized leading edges.
Once the catch 26 has intercepted the leading edge 24 and the position of at least one of the spread carriages 16, 18 is recorded, the catch 26 may be retracted to permit the continued motion of the leading edge until at least one of spread carriages 16, 18 reaches the extended position and leading edge 24 is substantially flat, as shown in
As may be seen in example shown in the above Table 1, when the spread carriages 16, 18 are in the first position (i.e., at 0 mm), the pressure threshold of the catch is set to 40 PSI. As the spread carriages 16, 18 move outward, the pressure threshold drops on linear scale. At the maximum position, the spread carriages 16, 18 may, for example, be roughly 112″ apart, or 56″ from the initial position, the pressure threshold having dropped to 0 psi. In alternate embodiments, the pressure threshold may drop non-linearly. Furthermore, it should be understood that the pressure thresholds are merely provided as examples will vary in accordance with variables such as the height between the catch and the spread carriages, the location of the first position, etc. By varying the pressure threshold in this way (or in similar ways), textiles of different sizes, makes, and materials, or textiles that have been laundered different numbers of cycles or have varying amounts of water retention, may be pulled flat without improperly stretching and thus damaging the textile.
Once the leading edge 24 of textile 20 is held substantially flat, leading edge 24 will extend, for example, along plane y (assuming the spread carriages 16, 18 have not also traveled upwards or downwards with respect to the textile spreader apparatus), as shown in
As mentioned above, the location of the extended position may be determined through a calculation based on the location of the catch 26 and at least one of the spread carriages 16, 18, once the catch 26 has intercepted the leading edge 24. One such calculation is depicted in connection with
As shown in
Once the leading edge 24 is intercepted by catch 26, distance X1 is measured. The values of first distance X1 and second distance X2 will be a function of each other and of the textile's 20 partial-length L. Because a portion of leading edge 24 of textile 20 is grasped within the clamps, distances X1 and X2 and partial-length L are measured or calculated with respect to the portion of leading edge 24 not grasped within clamps—indeed, this is the only portion of leading edge 24 that may be measured and pulled flat. Note that although only one X1 is shown, both spread carriages 16, 18 have moved away from the initial position in substantially opposing directions. In this embodiment, spread carriages 16, 18 move away from the initial position in a similar manner, and thus, since the distance from initial position X1 is substantially the same for both spread carriages 16, 18, it is only necessary to calculate the distance X1 for both spread carriages 16, 18. In alternate embodiments, spread carriages 16, 18 may move outward from the initial position at differing or inconsistent rates, thus requiring the position of each spread carriage to be measured separately.
In one embodiment, the distance X1 may be measured by the servos of spread carriages 16, 18. The position of the servos of spread carriages 16, 18 may be, for example, relayed on a regular basis to controller 14. It should be appreciated, however, that distance X1 may be measured in any other suitable for way. For example, in an alternate embodiment, the amount of time that has elapsed between the actuation of spread carriages 16, 18 and the interception of the leading edge by catch 24 may be determined. If the velocity of the spread carriages 16, 18 is known, multiplying the elapsed time by the known velocity will yield the distance X1.
First distance X1 is thus known and may be used in conjunction with known height H. Similarly, when the spread carriages 16, 18 are at intermediate position P2, the height H of the vertex V is also known with respect to the initial position, having either been determined a priori or measured, for example, via a sensor or a mechanical measuring assembly, if the location of the catch changes.
As height H and the first distance X1 are known, partial-length L (which spans the gap between the catch 26 and one of spread carriages 16, 18) may be calculated by setting the initial position P1, intermediate position P2, and location of catch as vertices of triangle. In this way, partial length L of the leading edge 24, spanning the gap between the catch 26 and one of the spread carriages 16, 18, forms the hypotenuse of the triangle, the distance X1 forms a first leg of the triangle, and the distance H from the initial position to the catch 26 forms the second leg of the triangle. Thus, because the intersection of the distance H and X1 form a right angle, we may determine the partial length L using the Pythagorean Theorem, as shown below.
L=√{square root over (x12+H2)}
As height H is theoretically equal to zero when the textile 20 is flat, the second distance X2—being the remaining distance that spread carriages 16, 18 must travel reach extended position P2—can be calculated after L is calculated, as shown below.
x
2
=L−x
1
The above equations may be simplified such that the second distance X2 can be calculated with only the known first distance X1 and the height H of the vertex V, as shown below.
x
2
=√{square root over (x12+H2)}−x1
Turning now to
Angle k may be known a priori. For example, when the textile spreader apparatus 12 is manufactured, assembled, or otherwise prepared for use, the angle k between plane y and the height H of the vertex V is measurable. Using known angle k and height H, and measured position P2, partial-length L can be calculated using the formula shown below.
L=√{square root over (X12+H2−2(X1)(H)cos(k))}
As height H is theoretically equal to zero when the textile 20 is flat, the second distance X2 can be calculated after edge length L is calculated, as shown below.
x
2
=L−x
1
Again, the above equations may be simplified such that the second distance X2 can be calculated with only the known first distance X1 and the height H of the vertex V, as shown below.
x
2
=√{square root over (X12H2−2(X1)(H)cos(k))}−x1
Referring back to
It should be understood that the above calculations represent only one of a multitude of ways of calculating the location of the extended position P3 using the known locations of the catch 26 and at least one of the spread carriages 16, 18. Indeed, any number of different triangles may be formed, once these locations are known, to determine the partial-length L, and, consequently, the location of the extended position. Further, any number of factors, such as the initial positions of each of the spread carriages 16, 18, the rate at which the spread carriages travel with respect to each other, the path that the spread carriages take, etc., may all be varied in alternate embodiments, these variations thus affecting the equations by which the partial length L and the location of the extended position are calculated.
In another embodiment, the textile spreader apparatus 12 utilizes a lookup table to determine the second distance X2. The lookup table comprises the calculated second distance X2, or the extended position, for different combinations of values for height H, first distance X1, angle k, and/or edge length L.
For example, the length of the leading edge may be determined according to a look-up table based only upon the location of the catch and of one of the spread carriages 16, 18, once the catch has intercepted the leading edge. Indeed, if the location of the catch does not change, or is otherwise known before initiating the spread sequence, the location of the extended position may be determined based on the location of one of the spread carriages alone, because the location of the catch 26, as well as the height H and the location of the initial position, remains constant.
The look-up table, may, for example, include a set of possible locations of one of the spread carriages 16, 18, each possible location being respectively associated with an extended position. Once the position of one of the spread carriages 16, 18, is known, this value is compared to the nearest possible location stored in the look-up table, and the associated respective extended position is retrieved. The accuracy of the look-up table is determined by the number of possible values and corresponding extended positions stored in the look-up table. However, steps may be taken to mitigate some level of granularity inherent to look-up tables. For example, if the measured location of one of the spread carriages 16, 18, is between two possible locations stored in the look-up table, the location of the extended position may be estimated by interpolating between the two stored extended position values corresponding to the two possible locations the measured location rests between. The position of one or more of the spread carriages 16, 18 may be input as a distance from a reference point, such as the initial position; however, in alternate embodiments, the position may be an arbitrary notation corresponding to the point along the track or otherwise located in space.
If the location of the catch 26 is not constant, the look up table may be expanded to include two inputs: (1) the location of the catch and (2) the location of at least one of the spread carriages 16, 18, in order to account for the varying height H. In another embodiment, the positions of both spread carriages 16, 18 may be inputs to the look-up table. Inputting the positions of both spread carriages 16, 18 may also be particularly necessary if the respective positions of both spread carriages 16, 18 is not consistent or predictable given the location of one of the spread carriages 16, 18 (e.g., the individual spread carriages 16, 18 move at unpredictable rates).
Referring now to
As shown in
Again, the pressure threshold for which the pivotable wand 28 retracts may diminish as the spread carriages 16, 18 move outward. The pressure threshold may be managed, for example, by the controller 14. This may be accomplished by regulating the flow of air into pressure sensor 38 according to the location of the spread carriages 16, 18, thus adjusting the sensed back pressure. As the spread carriages move in substantially opposing directions, the pressure may be reduced based on the detected location of the spread carriages 16, 18. Note that if the spread carriages were to stop at any time, the change in back pressure would also hold steady on the given value for the position of spread carriages 16, 18.
Turning now to
After intercepted leading edge 24, and as the leading edge 24 is pulled by the spread carriages 16, 18 toward plane y, the wand 28 rotates from the extended position to the retracted position. Thus, in the period when the pivotable wand 28 is in the lowered position, the spread carriages 16, 18 are in the initial position or are moving toward or in the intermediate position, and when the wand 28 is in the retracted position, the spread carriages 16, 18 have progressed beyond the intermediate position and are in or are moving toward the extended position.
While embodiments of the present invention has been particularly shown and described with reference to certain exemplary embodiments, it will be understood by one skilled in the art that various changes in detail may be effected therein without departing from the spirit and scope of the invention as defined by claims that can be supported by the written description and drawings. Further, where exemplary embodiments are described with reference to a certain number of elements it will be understood that the exemplary embodiments can be practiced utilizing either less than or more than the certain number of elements.
