Patent Publication Number: US-9427093-B2

Title: No-glue pocketed spring unit construction

Description:
CROSS-REFERENCE 
     This application is a non-provisional of, and claims priority from, U.S. Provisional App. No. 62/024,451, which is hereby incorporated by reference. 
    
    
     BACKGROUND 
     The present application relates to methods, devices and systems for no-glue construction of pocketed inner spring units, and more particularly to methods and systems for using Joule heating (welding using current-heated wire) to construct pocketed inner spring units. 
     Note that the points discussed below may reflect the hindsight gained from the disclosed inventions, and are not necessarily admitted to be prior art. 
     Connecting rows of pocketed springs together using a scrim sheet generally causes a trampoline-like effect, i.e., compressing springs in one part of the unit pulls on another part of the unit. 
     Glue connections between pocketed springs generally provide a “crunchier” feeling to a completed pocketed spring unit than connections made by thermal welding. 
     SUMMARY 
     The inventor has discovered surprising new approaches to methods and systems for manufacturing glueless pocketed spring cushioning units for use in mattresses and other cushioning assemblies. Rows of pocketed springs preferably comprise multi-pocketed spring modules, springs having uniform coil diameter, ones of said modules comprising more than two pocketed springs welded together to leave a central opening. Rows of pocketed springs are retained in position by pins, and are transferred to corresponding rows of probes and anvils which pinch layers of fabric together and form welds using current passed through heating elements on the probes. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The disclosed inventions will be described with reference to the accompanying drawings, which show important sample embodiments and which are incorporated in the specification hereof by reference, wherein: 
         FIG. 1  schematically shows a machine for welding rows of pocketed spring modules to each other. 
         FIG. 2  schematically shows a machine for welding rows of pocketed spring modules to each other. 
         FIG. 3  schematically shows a machine for welding rows of pocketed spring modules to each other. 
         FIG. 4  schematically shows a machine for welding rows of pocketed spring modules to each other. 
         FIG. 5  schematically shows a machine for welding rows of pocketed spring modules to each other. 
         FIG. 6  schematically shows a machine for welding rows of pocketed spring modules to each other. 
         FIG. 7  schematically shows a machine for welding rows of pocketed spring modules to each other. 
         FIG. 8  schematically shows a machine for welding rows of pocketed spring modules to each other. 
         FIG. 9  schematically shows a machine for welding rows of pocketed spring modules to each other. 
         FIG. 10  schematically shows a machine for welding rows of pocketed spring modules to each other. 
         FIG. 11  schematically shows an example of a mattress which has a core of many pocketed spring units which are mechanically joined together without glue, using a process like that shown in  FIGS. 1-10 . 
         FIG. 12  shows an example of a process for welding rows of pocketed spring modules together. 
         FIG. 13A  schematically shows a sealing head for welding rows of pocketed spring modules to each other. 
         FIG. 13B  schematically shows a sealing head for welding rows of pocketed spring modules to each other. 
         FIG. 14A  schematically shows a probe. 
         FIG. 14B  schematically shows an exploded view of a probe. 
         FIG. 15  schematically shows an anvil. 
         FIG. 16  schematically shows a machine for welding rows of pocketed spring modules to each other. 
     
    
    
     DETAILED DESCRIPTION OF SAMPLE EMBODIMENTS 
     The present application discloses new approaches to constructing pocketed spring units. In particular, the inventor has developed various systems and methods for NO-GLUE construction of pocketed spring units. 
     The disclosed innovations, in various embodiments, provide one or more of at least the following advantages. However, not all of these advantages result from every one of the innovations disclosed, and this list of advantages does not limit the various claimed inventions.
         pocketed spring unit construction uses NO GLUE;   pocketed spring units, and cushioning assemblies incorporating pocketed spring units, are more comfortable and luxurious-feeling;   cost-effective welding of entire rows of pocketed springs, or of an entire cushioning unit;   high cushioning unit manufacturing throughput;   none of the connections in pocketed spring units are glue connections;   reduced cost of pocketed spring unit construction;   reduced cost of pocketed spring unit welding machines;   stronger connections between rows of pocketed springs;   reduced environmental impact of pocketed spring unit construction;   reduced environmental impact of cushioning assembly construction and maintenance;   rows of pocketed springs, or even an entire cushioning unit, can be fully welded together in a single weld event, with controllable vertical weld location, extent, width, and strength;   reduced weight of pocketed spring unit;   reduced weight of cushioning assembly;   lower cushioning assembly transportation cost per unit;   reduced likelihood of unmoored pockets;   reduced likelihood of loose springs;   increased cushioning unit durability; and   enables unitary welds of the full vertical extent of pocketed spring modules.       

     The numerous innovative teachings of the present application will be described with particular reference to presently preferred embodiments (by way of example, and not of limitation). The present application describes several inventions, and none of the statements below should be taken as limiting the claims generally. 
     The inventor has discovered surprising new approaches to methods and systems for manufacturing glueless pocketed spring cushioning units for use in mattresses and other cushioning assemblies. Rows of pocketed springs preferably comprise multi-pocketed spring modules, springs having uniform coil diameter, ones of said modules comprising more than two pocketed springs welded together to leave a central opening. Rows of pocketed springs are retained in position by pins, and are transferred to corresponding rows of probes and anvils which pinch layers of fabric together and form welds using current-heated wires in the probes. 
     “Cushioning assembly” and “cushioning unit” are defined herein as any cushioning structure incorporating pocketed springs, e.g., a mattress, couch or cushion. 
     “Heating element” is used herein to refer to a length of material, preferably a wire (e.g., steel or other metal wire), that will repeatably produce approximately the same temperature when approximately the same current is passed through it for approximately the same amount of time (using Joule heating, also called ohmic heating herein). “Approximately the same” temperature, current and time meaning sufficiently bounded to produce results within tolerances of cushioning unit product requirements and/or specifications. 
     In preferred embodiments, pockets are formed gluelessly by welding together layers of a flexible material, generally plastic, such as spun bonded polypropylene weighing 1.5 ounces per square yard, using Joule heating effected by current passed through a heating element compressed against the fabric. By forming pockets of a chosen size on a chosen length and width of fabric, rows of pockets of a chosen length and sized for a chosen diameter and length of spring can be produced. 
     In preferred embodiments, uniform diameter springs are used. Uniform diameter springs can be manufactured by custom winding high tensile strength wire with highly uniform shape and thickness. 
     Some embodiments use or include microcoil springs, which are small springs suitable for use in pocketed spring units incorporated into, for example, upholstery. 
     Springs are inserted into pockets to form pocketed springs. Springs can be inserted into pockets oriented horizontally through a seam on top of the pocket, and then beaten until they reorient vertically. Generally, this results in a pocketed spring that, in a completed cushioning assembly, can only be oriented in a single direction. For example, a bed made in this way is typically called “one sided”. 
     Preferably, springs are inserted oriented vertically through a seam on the side and allowed to expand to fill the pocket. 
     Pockets can be fashioned to be shorter than an uncompressed spring, so that pocketed springs are constantly under load (“preloaded”). This generally increases the useful lifetime of the spring, by allowing its spring constant to remain higher, for longer. Preloaded springs are generally inserted vertically compressed, and allowed to expand vertically to fill the pocket. 
     A row of pocketed springs, in which pocketed springs are connected to adjacent pocketed springs (e.g., by the same fabric that forms the pockets) can be formed as shown and described in, for example, U.S. Pat. No. 6,260,331. 
     Rows of pocketed springs can be fashioned into rows of multi-pocket “modules”, comprising more than two—preferably, four—pockets welded together to leave an opening (a hole) in the middle. Rows of modules can then be welded together, and those rows can then be welded to each other to form pocketed spring units. Pocketed spring modules can be assembled as shown and described in, for example, U.S. Pat. No. 6,347,423. Preferably, openings have uniform spacing from each other. This can be accomplished by, e.g., nearest-adjacent (not catty-corner) springs in modules having uniform spacing from each other, and modules having uniform spacing from each other. 
     Multiple horizontally-adjacent rows of pocketed springs can be connected together to form pocketed spring cushioning units. Generally, pocketed spring units look like arrays of pocketed springs from above. 
     Springs in completed pocketed spring units are typically compressed very flat and rolled up into tight cylinders for shipping. 
     Glue can be used in layers of a cushioning assembly manufactured as disclosed herein, but preferably is not used in the pocketed spring cushioning unit layer(s) assembled using thermal welds. 
       FIG. 1  schematically shows a machine  100  for welding rows of pocketed spring modules  200  to each other. In  FIG. 1 , the machine is in an initial position, without pocketed spring modules  200 . Two rows of upward-facing vertical positioning pegs  102  are disposed to penetrate holes  104  in a liftable table  106 , are attached to a stable surface  108  beneath the liftable table  106 , and are configured to hold two rows of pocketed spring modules  200  in position (see, e.g.,  FIG. 2 ). Rows of pegs  102  are aligned so that a line through a row of pegs  102  is perpendicular to a line between two adjacent pegs  102  in two different rows. (The left-most row of pegs  102  and row of pocketed spring modules  200  in the figures, generally closest to a module  200  entrance side of the machine  100 , will be called herein the “front-most” rows. The right-most rows, generally closest to a cushioning unit exit side of the machine  100 , will be called the “far-most” rows. Corresponding directions on the machine are “front-ward” and “far-ward”.) 
     As shown in  FIG. 1 , the front row of downward facing phalanges are the probes  110 , and the far-most row of downward facing phalanges are anvils  112 . Advantageously, the probes  110  and the anvils  112  are spaced at approximately the same intervals as the upward-facing pegs  102 , and are positioned so that when they are moved (e.g., on a rail system  114 , as shown) front-wards to their front-most position, they vertically align with the pegs  102 . 
     Probe  110 /anvil  112  pairs are configured to compress and heat the plastic fabric of the pockets to a pressure and temperature suitable for welding together multiple layers (generally two or more layers) of the plastic fabric. Preferably, probes  110  are embodied as shown in  FIGS. 14A and 14B ; anvils  112 , as shown in  FIG. 15 ; and sealing heads  300 , comprising (inter alia) probes  110 , anvils  112 , and a rail system  116  (or other transport) to open and close them, as shown in  FIGS. 13A and 13B . 
     Preferably, the heating element  302  on a probe  110  is located on a long, fabric-facing side of the probe  110  oriented towards a corresponding anvil (as shown, a horizontally-facing side). This simplifies the mechanical operation of the probes  110  and anvils  112  inserting into the central openings (holes  202 ) in individual modules  200  and pressing together, so that the one or more contact regions  304  on the anvils  112  and the heating elements  302  on the probes  110  press together with the spring pocket fabric between, allowing welding in the location(s) corresponding to the contact region(s)  304 . 
     Welding occurs when a probe  110  and an anvil  112  move together (preferably, multiple probe  110 /anvil  112  pairs simultaneously), and the heating element  302  in the probe  110  and a facing surface of a corresponding anvil  112  (a contact region  304 ) press flush against each other, with the layers of fabric to be welded pressed between them. The heating element  302  is then activated with a welding pulse at a (1) current, (2) for a time and (3) at an amount of pressure between the probe  110  and the anvil  112  selected to weld the particular density and thickness of plastic fabric of the pockets to a desired weld strength. The probes  110  and anvils  112  can be pushed together by, e.g., a rail system  116  (as shown in  FIG. 1 , a rail system  116  using air actuators separate from the rail system  114  that moves the probes  110  and anvils  112  front-ward and far-ward together). 
     Spacing of pegs  102 , probes  110  and anvils  112  can be adjustable to correspond to, e.g., module  200  diameter and hole  104  placement. 
     The table  106  through which the pegs  102  are disposed includes a lift mechanism  120  to push the liftable table  106  upwards; the upward-moving table  106  pushes upwards rows of pocketed spring modules  200  disposed on the pegs  102 . The lift mechanism  120  shown in  FIG. 1  comprises servo motors  122 . The table  106  also includes an extractor plate  124 , described in more detail with respect to  FIGS. 6 and 8 . 
       FIG. 2  schematically shows a machine  100  for welding rows of pocketed spring modules  200  to each other. In embodiments as shown in  FIG. 2 , rows of pocketed spring modules  200  are disposed on, and spatially aligned by, the pegs  102 . Here, pocketed spring modules  200  comprise four pocketed springs. Preferably, two rows of pocketed springs are welded together to form modules  200  prior to the modules  200  being loaded onto the machine  100 , allowing entire rows of modules  200  to be treated as individual, separate units. 
     Module holes  202  are aligned with pegs  102 , and rows of modules  200  are dropped or pushed onto corresponding rows of pegs  102 . Advantageously, springs within the pockets are of uniform size, and modules  200  are spaced a uniform distance from each other. Uniform sizing can be advantageously enhanced by using springs made from high tensile wire of even thickness and consistent shape, and by using substantially the same length of wire to form each coil. 
       FIG. 3  schematically shows a machine  100  for welding rows of pocketed spring modules  200  to each other. As shown in  FIG. 3 , the probes  110  and anvils  112  move leftward together to be vertically aligned over the pegs  102 , and thus also over the holes  202  described by the middles of the pocketed spring modules  200 . 
       FIG. 4  schematically shows a machine for welding rows of pocketed spring modules  200  to each other. As shown in  FIG. 4 , the liftable table  106  has risen, pushing the rows of pocketed spring modules  200  onto the corresponding probes  110  and anvils  112  and off of the pegs  102 . 
       FIG. 5  schematically shows a machine  100  for welding rows of pocketed spring modules  200  to each other. As shown in  FIG. 5 , the probes  110  and anvils  112  are pushed together to perform a weld and to move the rows of modules  200  to a dropoff position where the probes  110  are aligned over a far row of pegs  102 . Preferably, the probes  110  and anvils  112  perform a weld while moving the modules into the dropoff position. 
     As shown in  FIG. 5 , the probes  110  and anvils  112  push together the fabric between them (and between two corresponding pairs of pocketed springs in different rows of pocketed spring modules  200 ). When a suitable pressure has been achieved, a welding pulse of current is propagated through the heating elements  302  in the probes  110 , heating the fabric to the point of melting together the layers of fabric compressed by respective probes  110  and anvils  112 . A non-stick material with a higher melting point than the fabric (e.g., Teflon, or a high-temperature plastic coated with Teflon or a similar material), interposed between the heating elements  302  and the fabric, keeps the melted fabric from sticking to the heating elements  302 . The vertical position of the region(s) where the heating elements  302  in the probes  110  and the contact region(s)  304  in the anvils  112  press flush against each other during welding generally corresponds to the vertical position of the weld. Preferably, the heating elements  302  and the contact regions  304  span the entire vertical extent of the plastic fabric between the probes  110  and anvils  112 . 
     Generally, the probes and anvils can place welds anywhere along a vertical line on the pocket fabric. Further, the strength of said welds is tunable by controlling the welding pulse current-time curve and the amount of pressure exerted by the probe against the corresponding anvil (with the pocket fabric therebetween). Different numbers, vertical placements and widths of welds can also be used to control use characteristics, such as firmness, of the resulting cushioning unit. 
       FIG. 6  schematically shows a machine  100  for welding rows of pocketed spring modules  200  to each other. In  FIG. 6 , the probes  110  and anvils  112  have moved, pushing the now welded together modules  200  so that the openings in the frontward row of modules  200  are aligned over the far row of pegs  102 . This places a far edge (or more) of the far row of pocketed spring modules  200  (as shown in  FIG. 6 , the row of modules  200  currently on the row of anvils  112 ) under the extractor plate  124 . 
     The extractor plate  124  has holes  126  corresponding to the locations of the probe  110  and the anvil  112 ; as shown in  FIGS. 6 and 7 , the holes  126  partially or fully surround the anvils  112  and/or the probes  110  when a front row of modules  200  is in position to be transferred to the far row of pegs  102 . 
       FIG. 7  schematically shows a machine  100  for welding rows of pocketed spring modules  200  to each other. In  FIG. 7 , the probes  110  and anvils  112  have separated and moved back to their original relative position, with the probes  110  now located over the far row of pegs  102 . 
       FIG. 8  schematically shows a machine  100  for welding rows of pocketed spring modules  200  to each other. The liftable table  106  is connected to, and rises and falls with, the extractor plate  124 , which is oriented approximately parallel to the liftable table  106 . When the table is lowered as shown in  FIG. 8 , the extractor plate  124  lowers too, pushing the now-joined rows of pocketed spring modules  200  off the probe  110  and the anvil  112 , and pushing the holes  202  of the front row of pocketed spring modules  200  onto the far row of pegs  102  (as explained above, the probes  110  were located over the pegs  102  in  FIG. 7 ). A crank  128  can be used to adjust the height of the liftable table  106  to correspond to the height of the pocketed spring modules  200 . 
       FIG. 9  schematically shows a machine  100  for welding rows of pocketed spring modules  200  to each other. In  FIG. 9 , a new row of pocketed spring modules  200  has been placed on the front row of pegs  102  by positioning the holes  202  of the modules  200  over the pegs  102  and dropping or pushing the row of modules  200  onto the pegs  102  (or otherwise inserting the pegs  102  into the holes  202 ). 
       FIG. 10  schematically shows a machine  100  for welding rows of pocketed spring modules  200  to each other. In  FIG. 10 , the probes  110  and anvils  112  have moved to vertically align with the front and rear rows of pegs  102 , respectively. This point in the process corresponds to  FIG. 3 , but with one far-most (right-most) row of pocketed spring modules  200  already welded to the middle row of pocketed spring modules  200  with a number of no-glue connections. 
       FIG. 11  schematically shows a mattress  1300 . Generally, a mattress  1300  comprises a core  1302 , upholstery and a fabric cover (typically called ticking). The core  1302  provides support for a user, upholstery cushions the core  1302 , and the fabric cover is wrapped around the core  1302  and upholstery and contributes both aesthetics and texture to the surface of the mattress  1300 . 
     In preferred embodiments, the core  1302  comprises many pocketed spring units  1304 . The upholstery can also comprise pocketed spring units, such as pocketed microcoil spring units. 
       FIG. 12  shows an example of a process for welding rows of pocketed spring modules  200  to each other. Pocketed spring modules  200  are loaded onto rows of pegs  102  in step  1400 . Paired probes  110  and anvils  112  (preferably arranged in rows) are positioned over the pegs  102  to receive the modules  200  in step  1402 . The liftable table  106  then pushes the modules  200  onto the probes  110  and anvils  112  in step  1404 , and the probes  110  and anvils  112  are pressed closed, with pocket material pressed between them  1406 . 
     The probes  110  and anvils  112  (preferably still closed together) move the modules  200  to a dropoff position while welding the rows of modules  200  together using a welding pulse through the respective heating elements  302  in step  1408 . Once the dropoff position is reached and the weld is completed, the probes  110  and anvils  112  open (move apart), the probes  110  are vertically aligned with the far row of pegs  102 , and the extractor plate  124  pushes the modules  200  onto the pegs  102  in step  1410 . Depending on whether the cushioning unit is planned to have more rows of modules  200  welded on (is not complete)  1412 , a new row of modules  200  is added to the front row of pegs  102  at step  1414 , and the process repeats from step  1402 ; or, if welding of rows of modules to form the cushioning unit is complete, then the cushioning unit can be removed from the assembly mechanism  1416 . 
     Alternatively, if the cushioning unit is complete at step  1412 , the modules  200  can be moved to a dropoff position away from the pegs  102 , so that the cushioning unit can easily be removed from the assembly mechanism  1418  (this behavior can be built into the assembly mechanism). 
       FIGS. 13A and 13B  schematically show a sealing head  300 . Preferably, a sealing head  300  comprises a probe  110  with a heating element  302  (see  FIGS. 14A and 14B ) that will heat up when current is passed through it; an anvil  112 , with a contact region  304  that is preferably detachable to allow reconfiguration (e.g., to one or more contact regions of varied and/or multiple separate vertical extent(s) and/or widths, by which size, shape and number of welds generated in a single weld event can be configured); and a mechanism for pushing the probe  110  and anvil  112  together for a weld, here a set of rails  116  as described above. A sealing head  300  can also include a timer interface  306  to control and/or display the duration of a welding pulse of current, and a pressure interface  308  to control and/or display the amount of pressure the probe  110  and anvil  112  will exert against the fabric during a weld. 
       FIG. 13A  shows the sealing head  300  with the probe  110  and anvil  112  in an open position (the heating element  302  is pointed out, but is not visible due to probe  110  orientation).  FIG. 13B  shows the sealing head  300  with the probe  110  and anvil  112  in a closed position 
       FIG. 14A  schematically shows a probe  110 .  FIG. 14B  schematically shows an exploded view of a probe  110 . 
     A length of non-stick material  402  (or a length of tape and/or other structural material(s) that is coated with non-stick material) overlays the heating element  302  (or is otherwise connected to the probe  110  and arranged) so that it is interposed between the heating element  302  and pocket spring fabric of a module  200  when a weld occurs. The non-stick material  402  prevents the heating element  302  from sticking to the (melted) pocket spring fabric. (The heating element  302  is referred to herein as being in “contact” with the fabric during a weld, regardless of whether non-stick material is interposed therebetween.) 
     One end of the heating element  302  is connected on each of a top portion  404  and a bottom portion  406  of the probe  110  (and to an electrical power source). The top portion  404  and bottom portion  406  are aligned by metal bars  408  that insert into holes in the bottom portion  406 . A spring  410  allows the top portion  402  and bottom portion  404  to be pushed apart and pulled together by expansion and contraction of the heating element  302  as a result of heating and cooling. Preferably, the non-stick material is glued (or otherwise attached) to only one portion, i.e., either the top portion  404  or the bottom portion  406 . 
     In the example embodiment shown in  FIGS. 14A and 14B , the probe  110  also comprises cover plates  412 . 
     As shown, the heating element  302  wraps around the end of the bottom portion  406  of the probe  110  (the bend in the heating element  302  conforms to the shape of the bottom end of the probe  110 ) to facilitate contact between the heating element  302  and the full vertical extent of pocket spring fabric of a module  200 , enabling welding of said full vertical extent in one welding event. Width and thickness of a heating element  302  can be selected based on, e.g., width of the probe  110 ; width and/or depth of the channel  414  (if any) in the probe  110  surface that the heating element  302  is disposed in; desired or maximum weld width; and desired resistivity (e.g., for temperature and/or efficiency control). Use of a channel  414  in which to recess the heating element  302  is preferred, e.g., to help control location and timing of a weld by preventing contact with and/or pressure of the heating element  302  on pocket spring fabric at a location where (or at a time when) a weld is not desired (or for a duration longer than desired). As shown, the channel  414  is defined on an anvil-facing side  416  of the probe  110  by the cover plates  412 . 
     The body  418  of the probe (at least, the portion near the heating element  302  and electrical connections thereto) is preferably made from a poor electrical and thermal conductor (e.g., an insulator), such as G7 Garolite (a high-temperature composite). 
       FIG. 15  schematically shows an anvil  112 . The connecting portion  420  of the anvil  112  connects to the rest of the sealing head  300 . The anvil body  422  holds a contact region  304 . When the anvil  112  and probe  110  close together to weld, the contact region  304  presses flush against the heating element  302 . The contact region  304  can be made of, for example, rubber. 
     “Contact region”  304  refers to that portion of the anvil  112  located and shaped to press flush against the heating element  302  in at least one location corresponding to a desired weld location on module pocket spring fabric pressed between the probe  110  and anvil  112 . 
     One “welding event” refers to the weld(s) formed by the one or more probe  110 /anvil  112  pairs that contemporaneously receive a single welding pulse of current each, without the probes  110  and anvils  112  being removed from the holes  202  of the rows of modules  200  during the period of the welding event. 
       FIG. 16  schematically shows a machine for welding rows of pocketed spring modules  200  to each other. 
     According to some but not necessarily all embodiments, there is provided: A method for glueless assembly of cushioning units, comprising: a) inserting one of at least one probe/anvil pair into openings in a first continuous row of connected multiple-coil modules, and inserting the other of said probe/anvil pair into openings in a second continuous row of connected multiple-coil modules, individual ones of said modules comprising more than two pocketed springs which together surround one of said openings, individual ones of said pocketed springs each comprising a spring inside a pocket made of a flexible material; b) moving said probe/anvil pair together such that at least one contact region on said anvil presses said material against at least one heating element connected to said probe, and applying current across said heating element to thereby weld said first and second rows of multiple-coil modules together; c) removing at least one of said first and second rows of modules from said probe/anvil pair; and repeating said steps (a), (b) and (c) until more than two rows of modules have been thereby welded together to form a cushioning structure having an extended area. 
     According to some but not necessarily all embodiments, there is provided: A mechanism for glueless assembly of pocketed spring units, comprising: at least one probe and at least one anvil, said probe and anvil configured to be inserted into openings in pocketed spring modules, individual ones of said modules comprising more than two pocketed springs which together surround one of said openings, and individual ones of said pocketed springs each comprising a spring inside a pocket made of a flexible material; said anvil having at least one contact region configured to press flush against said heating element when said probe and anvil are closed together; and at least one heating element mounted on an anvil-facing side of said probe and configured to thermally weld pocketed spring fabric when said probe and said anvil press together and current is propagated through said heating element. 
     According to some but not necessarily all embodiments, there is provided: A method for glueless assembly of cushioning units, comprising: a) inserting multiple double-rows of probe/anvil pairs into openings in multiple continuous rows of connected multiple-coil modules, ones of said pairs in ones of said double-rows inserting into openings in ones of said rows of modules, others of said pairs inserting into openings in adjacent ones of said rows of modules, different double-rows of probe/anvil pairs inserting into different twos of said rows of modules; wherein individual ones of said modules comprise more than two pocketed springs which together surround one of said openings, and wherein individual ones of said pocketed springs each comprise a spring inside a pocket made of a flexible material; b) moving said probe/anvil pairs together such that said anvils press said material against at least one heating element disposed along a facing side of corresponding ones of said probes, and applying current across said heating element to thereby weld said pairs of rows of multiple-coil modules together; c) removing said pairs of rows of modules from said double-rows of probe/anvil pairs; and d) repeating step a) such that said double-rows of probe/anvil pairs are inserted into different twos of said rows of modules that were not welded together in step b), and then repeating step b); wherein said rows of modules are sufficient to form a pocketed spring component of a mattress, and whereby said rows of modules are welded together in two welding events. 
     According to some but not necessarily all embodiments, there is provided: A mechanism for glueless assembly of pocketed spring units, comprising: multiple alternating rows of probes and anvils, said probes and anvils configured to be inserted into openings in pocketed spring modules, individual ones of said modules comprising more than two pocketed springs which together surround one of said openings, and individual ones of said pocketed springs each comprising a spring inside a pocket made of a flexible material; ones of said anvils having at least one contact region on at least two probe-facing sides, said contact regions configured to press flush against said heating element when said probe and anvil are closed together; and at least one heating element mounted on each of the anvil-facing sides of ones of said probes and configured to thermally weld pocketed spring fabric when ones of said probes and ones of said anvils press together and current is propagated through said heating element. 
     According to some but not necessarily all embodiments, there is provided: A method for glueless assembly of pocketed spring units, comprising: a) inserting multiple alternating rows of probes and anvils into corresponding openings in multiple continuous rows of connected multiple-coil modules, individual ones of said modules comprising more than two pocketed springs which together surround one of said openings, individual ones of said pocketed springs each comprising a spring inside a pocket made of a flexible material; b) moving adjacent pairs of said probes and anvils together such that said anvils press said material against at least one heating element disposed along facing sides of said probes, and applying current across said heating elements to thereby weld together pairs of modules in said rows of modules; and c) repeating said moving such that said probes and anvils close together with the other adjacent anvil or probe, and repeating said applying current to thereby weld together different pairs of modules in said rows of modules. 
     Modifications and Variations 
     As will be recognized by those skilled in the art, the innovative concepts described in the present application can be modified and varied over a tremendous range of applications, and accordingly the scope of patented subject matter is not limited by any of the specific exemplary teachings given. It is intended to embrace all such alternatives, modifications and variations that fall within the spirit and broad scope of the appended claims. 
     As used herein and as is apparent from the disclosure set forth hereinabove, “left” and “right” (and “front” and “far”) are arbitrary terms signifying generally opposing directions, respectively oriented towards pre-weld (generally, welding machine entrance) and post-weld (generally, welding machine exit) pocketed spring module positions as shown in  FIGS. 1-10 . 
     In some embodiments, the probes and anvils start in different positions than shown in  FIG. 1 . 
     In some embodiments, probe/anvil pairs move the rows of modules over to a dropoff position once the modules are fully off of the pegs; in some embodiments, once the modules are fully loaded onto the probe/anvil pairs; in some embodiments, at some (or any) time between. 
     In some embodiments, a pocketed springs in a row of pocketed springs may be connected to each other by material other than the material used to form pockets. 
     In some embodiments, pocketed springs may be formed by welding pocketed springs to a strip or strips of flexible material (e.g., the material used to form pockets). 
     In some embodiments, different lengths or portions of the probe may have one or more separate heating elements. 
     In some embodiments, multiple separate heating elements are side-by-side in a probe. 
     In some embodiments, rows of pocketed spring modules can be automatically fed onto rows of pegs. 
     In some embodiments, rows of pocketed spring modules can be manually fed onto rows of pegs. 
     In some embodiments, the probes and anvils are moved leftward and rightward together (or separately) by the same transportation system that pushes them together and apart for welding. 
     In some embodiments, lifting mechanisms other than servo motors are used to lift the liftable table, such as hydraulic motors. 
     In some embodiments, other transportation types (than rails) and motor types are used to move the probes left-wards and right-wards, and together and apart, than described hereinabove. 
     In some embodiments, the probe moves to the anvil to press flush against the anvil prior to welding. 
     In some embodiments, the anvil moves to the probe to press flush against the probe prior to welding. 
     In some embodiments, the probe and anvil both move to press flush against each other prior to welding. 
     In some embodiments, probe/probe pairs are used. 
     The probe is described herein with a particular internal structure that compensates for expansion of the heating element during a weld. In some embodiments, the probe has a different structure that compensates for expansion of the heating element during a weld, e.g., using a flexible/mobile attachment between the heating element and the probe. 
     In some embodiments, expansion of the heating element is minimized and the internal structure of the probe is simplified. 
     In some embodiments, one or more welds is performed as described above; or when the liftable table has not fully transferred the modules to the probe/anvil pairs; or when a portion of the modules has been pushed above the top(s) of the heating element(s); or after complete transferal, before, during or after moving the modules to a dropoff position; or during dropoff; or some or any combination thereof. 
     In some embodiments in which probes have more than one heating element, different ones of the heating elements can be activated separately. 
     In some embodiments, the probes and/or anvils push the modules into a dropoff position while the probes and anvils are separated from each other (open). 
     In some embodiments, something other than the probes and/or anvils (e.g., a pusher rod or plate) moves the modules into a dropoff position. 
     Particular left/right orientations of the probe and anvil have been described and shown with respect to the disclosed inventions. It will be apparent to one of ordinary skill in the arts of machine engineering of manufacturing machinery that alternative orientations of probe/anvil pairs are possible; e.g., reversed orientation (probes switched with anvils); or at +/−30 degrees from the front-ward/far-ward axis of the welding machine (the latter orientation(s), for example, to weld rows of hexagonal  6 -pocketed spring modules together); or orthogonally to a feed axis of the welding machine (e.g., to weld disjoint subrows of modules together). 
     It will also be apparent to said person of ordinary skill that double rows of probe/anvil pairs need not be fully segregated (i.e., that a row can consist of both probes and anvils). 
     In some embodiments, probe/anvil pairs and/or rows of pegs can be arranged otherwise than in orderly rows. 
     In some embodiments, heating element(s) in a probe and contact region(s) in an anvil are located at, at part of, or including where the probe presses against the anvil (with the fabric between them). 
     In some embodiments, one or more probe/anvil pairs can be configured to open and close at different times from other probe/anvil pairs. 
     In some embodiments, different probe/anvil pairs can be caused to weld at different vertical positions. 
     In some embodiments, for some welding events, some of the probes, and/or some of the heating elements in some of the probes, are not transmitted a welding pulse of current. 
     In some embodiments, probe/anvil pairs can close at different times from each other. 
     In some embodiments, probes have more than two respectively movable, spring-loaded (or similarly movement-restrained) portions. 
     In some embodiments, different probes can be transmitted different welding pulses (e.g., to create different strength welds). 
     In some embodiments, probes have multiple heating elements in different vertical locations. 
     In some embodiments, different heating elements in different probes, or in a single probe, have different widths, lengths and/or resistivities. 
     In some embodiments, the resistivity of a heating element varies along its length. 
     In some embodiments, the resistivity of a heating element varies laterally (across its width). 
     In some embodiments, anvils have multiple contact regions in different vertical locations. 
     In some embodiments, anvils have multiple contact regions side-by-side with each other. 
     In some embodiments, different contact regions in different anvils, or in a single anvil, have different widths and/or lengths. 
     In some embodiments, hybrid probe/anvil phalanges, individual phalanges having both heating element and contact region portions, can be used. In some embodiments, a hybrid probe/anvil phalange can have a heating element on one side, and a contact region on another (e.g., opposite-facing) side. 
     In some embodiments, rather than a pressure switch, an eye or other sensing device is used to determine when to transmit the (current) welding pulse and start the timer for welding pulse duration. 
     In some embodiments, welding pulse start timing is controlled based on when the probe and anvil close together, rather than or in addition to a sensing device. Other strategies can also be used to control welding pulse start timing. 
     In some embodiments, different vertical positions and extents where a probe and anvil press flush together can be controlled to be under different amounts of pressure. 
     In some embodiments, heating elements are coated with a high temperature non-stick material. In some embodiments, a high temperature non-stick material overlays, rests upon, is attached to, sheathes, or surrounds a heating element, or otherwise interposes between the heating element and the fabric during a weld. 
     In some less preferred embodiments, non-stick material is not used. 
     Particular up/down orientations have been described hereinabove with respect to, e.g., the lifting table and extractor plate. It will be apparent to one of ordinary skill in the arts of machine engineering of manufacturing machinery that alternative orientations (rather than along a z axis, or along an axis inverted from that described herein) are possible. 
     In some embodiments (and preferably), the springs are in the pockets prior to welding. 
     In some embodiments, as will be apparent to those of ordinary skill in the arts of machine engineering of manufacturing machinery, contact regions on anvils can be made of various materials. 
     In some embodiments, three or more rows of pocketed springs are welded together substantially simultaneously. 
     In some embodiments welding three rows of modules together substantially simultaneously, for a line of modules containing one module from each row, two pairs of probes and anvils perform welds at a given horizontal position; in other such embodiments, an anvil moves sequentially to two different probes at a given horizontal position; in other such embodiments, a probe moves sequentially to two different anvils at a given horizontal position. 
     In some embodiments, probes have heating elements on both anvil-facing sides. In some embodiments, anvils have contact regions on both probe-facing sides. In some such embodiments, one or both exterior (most front-ward and most far-ward) rows of probes and/or anvils has heating elements and/or contact regions on only one side of some or all of the probes and/or anvils in said row(s). 
     In some embodiments, two probes or anvils, or a probe and an anvil, are inserted into openings in modules, and rows of modules are welded to both adjacent rows of modules simultaneously. 
     In some embodiments, a weld is performed while the probes and anvil are moving relative to the rows of pegs. 
     In some embodiments in which the upholstery comprises rows of pocketed microcoil springs, the core can be of a type other than pocketed springs, e.g., continuous coils. 
     In some embodiments, rows of modules comprise disjoint subrows of modules, such that two disjoint subrows of modules are not connected to each other. 
     In some embodiments using disjoint subrows of modules, disjoint subrows comprising a first row are connected to each other when they are welded to a full row of modules, or welded to a subrow of modules that is disjoint from other subrow(s) of modules comprising a corresponding second row at a location that is not aligned with the disjunction(s) in the first row. 
     In some embodiments using disjoint subrows of modules, disjoint subrows are connected to form a non-disjoint row of modules by welding pocket fabric of disjoint subrows at the location of the disjunction. 
     In some embodiments, a row of pocketed springs (not modules) is configured to be positioned by pegs and welded to another row of pocketed springs (not modules); for example, using openings described by cylinders (open at top and bottom) or rings formed from excess pocketed spring fabric, or welded onto the rows of pocketed springs. In some such embodiments, each said row of pocketed springs is itself a doubled row of pocketed springs. 
     In some embodiments, the liftable table comprises only sufficient structure to transfer the rows of modules from the locator pins to the probe/anvil pairs, or is a continuous structure except where penetrated by locator pins, and can generally be anything between (e.g., a set of parallel strips, or strips in a criss-cross pattern, or any other shape or pattern capable of pushing rows of modules from the locator pins onto the probe/anvil pairs). In some embodiments, rows of modules are supported by a stationary or separately movable resting table in addition to or instead of the liftable table when the liftable table is at a position where rows of modules are fully loaded onto the locator pins (or at a lowest position). 
     Preferably one “module” of pocketed springs includes exactly four pocketed springs which totally surround a vertical opening which extends for the full height of a pocketed spring. However, in alternative and less preferred embodiments, more or fewer pocketed springs can be used to define a single module. 
     In some embodiments, pocketed spring modules comprise pocketed springs having uniform coil-to-coil distance in a length direction of the cushioning unit, and different uniform coil-to-coil distance in a width direction of the cushioning unit. 
     In some embodiments, a weld is be performed on four or more layers of pocket fabric, e.g., if the modules are formed from pairs of rows of pocketed springs welded together, and the rows of pocketed springs are pocketed in pockets formed from a long single sheet of fabric doubled over width-wise. 
     The pockets which will contain the springs can be formed, for example, from a continuous strip of folded polymer material. Welds are formed across this strip to separate the pockets from each other. As noted above, the pockets preferably have openings on their sides where a flattened coil spring can be inserted and released; once the coil spring is allowed to expand into the pocket, its ends will stay at the ends of the pocket. 
     Two such strips can then be welded together at every other weld location. This produces a strip of modules, where each module includes four pocketed spring units surrounding an opening. Such a strip of modules is shown in  FIG. 2  and the following figures. 
     Optionally the strip of modules can be trimmed to the desired width (or length) of the finished structure before the steps of  FIGS. 1-10  are performed. However, alternatives are possible, as will be readily recognized by those of ordinary skill in the arts of machine engineering of manufacturing machinery. 
     In some embodiments, alternative shapes can be used for the extractor plate, such as multiple extractor fingers, or an extractor rod parallel to the table and to the axis formed by a row of modules (i.e., from one end of the row to the other end of the row). 
     In some embodiments, a far edge (or more) of a front row of modules located on the probes is under the extractor plate when the front row of modules is in position to be transferred to the far row of pegs. 
     In some embodiments, the extractor plate is shaped to push on different portions of the front and far rows of modules than described above. 
     In some embodiments, a manual or automated mechanism other than a crank can be used to control the height of the table. In some embodiments, a crank or other mechanism can be used to control the height of the extractor plate. 
     In some embodiments, multiple welds for rows of modules are performed substantially simultaneously; in some embodiments, welds for said rows are (or can be) performed sequentially. 
     In some embodiments, pockets have insertion slots in the side. 
     In some embodiments, pocket material is a sheet of flexible polymer. 
     In some embodiments, coil springs have non-uniform (but known) diameter. 
     In some embodiments, coil springs have non-uniform (but known) spacing from each other. 
     In some embodiments, all rows of modules are transferred from the pegs to the probes and anvils substantially simultaneously. 
     In some embodiments, pegs are steel, and have approximately frustoconical tips. In some embodiments, pegs have other conical, prismatic, or otherwise much-longer-than-wide and approximately straight shapes, with tips configured to penetrate modules&#39; central openings (e.g., square prism with a hemispherical tip). 
     In some embodiments, the liftable table and extractor plate can move separately. 
     In some embodiments, the extractor plate is mechanically connected to the liftable table at an adjustable distance therefrom. 
     In some embodiments, probe/probe pairs (both probes having current-heated wires, which press against each other with fabric between) are used to form welds; in which case, probes can be configured to act as both probes and anvils. 
     Additional general background, which helps to show variations and implementations, may be found in the following publications, all of which are hereby incorporated by reference: U.S. Pat. No. 5,772,100; U.S. Pat. No. 3,844,869; U.S. Pat. No. 4,234,983; U.S. Pat. No. 4,401,501; U.S. Pat. No. 6,131,892; U.S. Pat. No. 6,260,331; U.S. Pat. No. 6,347,423; U.S. Pat. No. 6,101,697; U.S. Pat. No. 6,021,627; U.S. Pat. No. 5,613,287; U.S. Pat. No. 5,553,443; U.S. Pat. No. 4,439,977; U.S. Pat. No. 4,485,506; U.S. Pat. No. 5,749,133; U.S. Pat. No. 5,613,287; U.S. Pat. No. 4,986,518; U.S. Pat. No. 4,906,309; U.S. Pat. No. 4,854,023; U.S. Pat. No. 4,523,344; U.S. Pat. No. 4,234,984; U.S. Pat. No. 3,251,078; U.S. Pat. No. 2,540,441; U.S. Pat. No. 1,226,219; U.S. Pat. No. 1,192,510; and U.S. Pat. No. 685,160; and published U.S. patent applications 20120311784, 20120091644, 20110191962, 20110107572, 20100218318, 20100212090, and 20080245690. 
     Additional general background, which helps to show variations and implementations, as well as some features which can be implemented synergistically with the inventions claimed below, may be found in the following US patent applications. All of these applications have at least some common ownership, copendency, and inventorship with the present application, and all of them, as well as any material directly or indirectly incorporated within them, are hereby incorporated by reference: U.S. Pat. No. 6,131,892; U.S. Pat. No. 6,260,331; U.S. Pat. No. 6,347,423; and U.S. patent application Ser. No. 14/158,811. 
     None of the description in the present application should be read as implying that any particular element, step, or function is an essential element which must be included in the claim scope: THE SCOPE OF PATENTED SUBJECT MATTER IS DEFINED ONLY BY THE ALLOWED CLAIMS. Moreover, none of these claims are intended to invoke paragraph six of 35 USC section 112 unless the exact words “means for” are followed by a participle. 
     The claims as filed are intended to be as comprehensive as possible, and NO subject matter is intentionally relinquished, dedicated, or abandoned.