CA1203678A - Method and apparatus for making filter socks - Google Patents

Abstract

METHOD AND APPARATUS FOR MAKING
FILTER SOCKS
Abstract of the Disclosure Apparatus for making milk filter socks from a longitudinally folded sheet of filter paper. The sheet of filter material is continuously fed along a conveying path past an ultrasonic welder which bonds together its free longitudinal edges. A stop mechanism located down-stream from the ultrasonic welder intermittently stops the sheet of filter material so that a second ultrasonic welder may transversely bond the sheet, and a cutting disc may transversely cut the sheet to provide an open end tubular structure. A dancer roll engaging one side of the sheet is slidably mounted for reciprocal movement in a direction normal to the plane of the conveying path and is located between the two ultrasonic welders. The dancer roll accumulates or takes up the slack in the sheet of filter material being continuously fed while the downstream end of the sheet is stopped during the transverse bonding and cutting operations. A method of making filter socks is also described herein.

Description

METHOD AND APPA:E2ATUS FOR MAKING
FILTER SOCKS
Background of the ~nvention The present invention relates to filters, and m~re particularly to a method and apparatus for making milk filter socks.
Mills filtar socks are used as in-line filters in pipeline milk systems. In general, the filter includes a tubular fabric sock which is mounted around a helical support that is attached at one end to a gasket.
In the past~ milk filter socks have been formed of a sheet of rayon which is folded longitudinally, and the longitudinal edges and a pair of adiacent end edges are hand sewn to provide an open end tubular sock. Filter socks have also been constructed utilizing a hot melt adhesive to join the longitudinal and end edges of the rayon material.
Filter socks made in accordance with either of the above procedures, however, lack strength and have considerable bulk. In addition, these prior filter socks did not, in all cases, have uniform filtering characteristics, nor did they have uniform cross-sectional areas which made the socks diffiault ~o install on the gasket.
More recently milk filter socks have been con-structed from randomly orientated, spun bonded, contlnuous polyester fibers with the longitudinal and end edges of the polyester material ultrasonically welded, as described in Zylka et al, U.S. Patent No. 4,292,180, which is assigned to the assignee of the present invention. Filter socks made in accordance with the Zylka et al patent have more unifoxm filtering and bonding characteristics as well as more uniform internal dimensions. As a result, it is desirable to provide a method and apparatus for making milk filtex socks in accoxdance with ~he Zylka et al patent which precisely applies the ultrasonic welds and eliminates any unnecessary manual labor.

1~36~8 Summary of the Invention A method and apparatus for making milk filter socXs for use in a pipeline milking system~ In accordance with the present invention, the apparatus includes feeding means for continously feeding a sheet of filter material having a pair of overlying web portions along a conveying path to a first joining means for bonding the adjacent free longitudinal edges of the overlying edge. A stop means located downstream from the first joining means intermittently stops the sheet of filter material to enable the sheet to be transversely bonded by a second joining means, and ~ut at a location adjacent the ~rans-verse bond. The use of continuous feeding at the upstream end together with intermittent cutting at the downstream end of the sheet of filter material enables the filter socks to be mass produced without unnecessary manual labor.
An accumulating means located between the first and second joining means is utilized to accumulate or take up the slack of the sheet of filter material as it is continuously fed while the downstream end of the sheet is stopped to accomplish the transverse bonding and cutting operations. The accumulating means may include a dancer roll engaging one side o~ the sheet of filter material which is slidably mounted for reciprocal movement in a direction normal to the plane of the conveying path of the sheet~
The dancex roll provides a simple and economical mechanism for taking up the slack which develops in the sheet of filker material when the downstream end of the shee-t is stopped to enable the transverse bonding and cutting to take place The first and second joining means preferably comprises ultrasonic welders, and the filter material preferably comprises a longitudinally folded sheet of randomly oriented, spun bonded, continuous polyester fibers.
The ultrasonic bond created by the welders results in fusion ~3--of the overlying web portions of the sheet providing a more effective bond and resulting in greater strength for the sockO The use of ultrasonic welders enables the bonds to be precisely applied on the sheet which results in a more uniform internal cross-section and enables the sock to be more readily installed on the gasket in a pipeline milk system. Additionally, the ultrasonic bond reduces the bulk of the sock enabling a greater n~mber of socks to be packed in a given size box or container.
The apparatus also includes scuffer means located upstream from the first joining means for scuffing the surface of the ~ilter material along the longitudinal edge margin of one of the web portions, and vacuum means located adjacent to and downstream from the scuffer means for removing any lint particles formed by the scuffer on the surface of the filter material. The scuffed surface of the sheet enhan~es: the effect of the ultrasonic welder to increase the strength of the ultra-sonic bond.
The transverse cut in the sheet of filtermaterial is made by a cutting means which includes a rotatable cutting disc positioned in one side of the sheet, reciprocating means for transversely reciprocating the cutting disc against the sheet, and clamping means for clamping the sheet adjacent the transverse cut on the upstream and downstream sides thereof. The transverse cut is preferabl~7 made closely adjacent to the transverse ultrasonic weld. This location for the transverse cut takes advantage of the vibrations of the sheet of filter material caused by the ultrasonic welcler during bonding and results in a cleaner cut through the sheet.
In another aspect of the invention, a method of making filter socks includes the steps of continuously feeding a sheet of filter material having a pair of 367~

overlying web portions along a conveying path, con-tinu-ously joining the adjacent free longitudinal edges of the overlying web sections as the sheet is conveyed along the pathJ intermittently s~opping the sheet of material at a location downstream from where the longi-tudinal edges are joined, joining the overlying web portions in a transverse direction while the sheet is stopped, cutting the overlying web portions in a trans-verse direction at a location adjacent to the transverse ioint while the sheet is stopped, and accumulating the sheet of filter ma~erial being continuously fed along the path while the sheet is stopped.
Other o~jects and advantages of the invention will appear from the following description.
Brief Description of the Drawings The drawings illustrate the best mode presently contemplated of carrying out the invention.
In the drawings:
Fig. 1 is a schematic side view of an apparatus ;Eor making filter socks constituting a preferred embodiment Oe the present invention;
Fig. 2 is a schematic top view oE the apparatus of Fig. l;
Fig. 3 is an enlarged fragmentary top view of thQ brake mechanism used for interrnitten-tly stopping the sheet of filter material;
Fig. 4 is a fragmentary side view in elevation with parts broken away of the brake mechanism shown in Fig. 3;
Fig. 5 is a section taken along the line 5-5 of Fig. 6;
Fig. 6 is ar end view taken along the plane of line 6-6 shown in Fig. 2; and Fig. 7 is a plan view of a milk filter sock made in accordance with the present invention.

3~

Description of Preferred Embodiment .. . . . .. ~ . _ . . .
Referring now to the drawings, Figs. 1 and 2 schematically illustrate a method and apparatus for making milk filter socks for use in a pipeline milking system in accordance with the present invention. The filter socks are comprised of a sheet of spun bonded, randomly oriented, continuous synthetic fibers such as polyester fibers~ For a more detailed description of the filter socks one should refer to the disclosure of Zylka et al, U.S. Patent No. 4,292,180, which is assigned to the assignee of the present invention.
As shown in Fig. 1, the continuous sheet 1 of synthetic fibers or filter material is stored on a drum or reel 2. The sheet 1 is fed through a folder 3 to be transported along a conveying path designated by the arrow 4 by means of three sets of drive rolls 5-7.
The folder 3 is of any conventional design and is utilized to lon~tiudinally fold the sheet 1 so that the sheet 1 has a pair of overlying web portions having a pair of opposite free longitudinal edges. The first set of drive rolls 5, i~e., the one furthest to the left or upstream as shown in Fig. 1, includes a lower roll`8 and an upper roll 9, only one o which need actually be driven. The rolls 8 and 9 are supported for rotation within a bearing support structure 10, as shown in Fig. 2, with the shçet 1 passing through the nip formed between rolls 8 and 9. Thus, as the rolls 8 and 9 are rotated the sheet 1 is pulled from its storage drum 2 through the folder 3 along the conveying path 4.
An adjustable guide means located upstream from the set 5 of drive rolls is utilized for transversely adjusing the position of sheet 1 so that it is properly oriented as it approaches the nip between roIls 8 and 9.
This adjustable guide mean~ include5 an adjustable guide member 11 slidably mounted for transverse movement with respect to the conveying path 4 on a table 12~ The ~i~3~;7~

table 12 includes an upstanding stationary side edge or guide member 13 on the side of sheet 1 ~orresponding to the side which has the free longitudinal edges. The adjustable guide member 11 is in the form of an angle member and is secured to table 12 by means of a pair of bolts 14. Table 12 includes a pair of spaced trans-versely extending elongated bolt holes 15 formed there-through which receive the shanks of bolts 14 and enable the guide member 11 to be adjusted transversely in order to accommodate different cross-sections or widths of sheet 1 depending upon the size filter sock desired.
After the sheet 1 of filter material passes through the nip formed by rolls 8 and 9 it passes around an idler roller and is fed to a first joining means ~or continuously joining or bonding the adjacent free longi-tunidal edges of the overlyins edge portions of sheet 1 as the sheet 1 is conveyed along path 4. As shown in Fig. 1, the joining means is located downstream from the set 5 of drive rolls, and includes an anvil 16 engaging the undersurface of sheet 1 and an ultrasonic horn or welder 17 positioned above sheet 1 on the opposite side of anvil 16. As shown in Fig. 2, anvil 16 is in the form of a roller rotatably mounted on bearing support structure 10 and includes a knurled portion 18 along one edge. The ultrasonic horn 17 may be of any con-ventional design and is positioned so that its nozzle is located directly above the knurled portion 18 of anvil 16. Thus, as the sheet 1 engages anvil 16 and passes over the knurled portion 18 the ultrasonic horn 17 operates to bond or fuse kogether the free longitudinal edges of sheet 1. The knurled portion 18 enables the fibers in the bonded areas to be ~used together with a series of alternate depressions and projections thereby increasing the surface area to enhance the bond between the longitudinal edges of sheet 1.

1;~367~3 In order to enhance the strength of the ultrasonic bond, there is included a scuffer 19 located upstream from the ultrasonic horn 17 and downstrearn from the folder 3. The scuffer 19 functions to scuff up or rough up the surface of the upper web portion of sheet 1 along its free longitudinal edge in order to enhance the effect of the ultrasonic horn 17. To accomplish this, scuffer 19 includes a circular head 20 slidably mounted on a shaft 21 which in turn is supported by a bracket 22 which is bolted to folder 3. The head 20 is forced downwardly against the upper surface of sheet 1 by means of a spring 23 encircling shaft 21. The sheet-engaging surface of head 20 contains a plurality of small beads or ri~ges thereon whicn scu~f or rough up the surface of sheet 1 when engaged therewith.
Scuffer 19 causes lint particles on the surface of sheet 1 which are required to be removed prior to being fed to the ultrasonic horn 17 so that a uniformly strong bond may be formed. To accomplish this, a vacuum nozzle 24 is positioned adjacent to and downstream from scuffer 19. The nozzle 24 is connected to a source of vacuum (not shown) and thus when positioned closely adjacent the upper surface of sheet 1 will pick up and carry away any lint particles ormed by scufer 19.
After the free longitudinal edges of sheet 1 are fused by ultrasonic horn 17, the sheet 1 is fed to the set 6 of drive rolls which includes a lower roll 25 and an upper roll 26, only one of which need actually be driven. The sheet 1 is engaged on opposite sides by rolls 25 and 26 and passes through the nip formed there-between to a tension roll 27. Roll 27 is rotatably mounted on a shaft 28 in a cantilevered fashion. Shaft 28 is mounted to one end o an arm 29 which in turn is mounted at its other end to a shaft 30. Shaft 30 in turn is 3S mounted to ano-ther arm 31 having its free end connected ~3~78 to a spring 32. Spring 32 is connected to a bracket 33 which is mounted on a supporting column 34. Bracket 33 includes a bearing block 35 which rotatably supports shaft 30. As seen bes~ in Fig. 1, the arms 29 and 31 project divergently from the opposite ends of shaft 30 so that roll 27 is forced upwardly against ~he under surface of sheet 1 by means of the force of spring 32.
Roll 27 thus maintains tension on sheet 1 as it is conveyed along path 4.
10After passing over tension roll 27, sheet 1 passes around an idler roller 36 mounted on column 34 and then around a second idler roll 37 mounted on column 34 above roll 36. After passing over roll 37, sheet 1 passes under a dancer roll 38 and then over another idler 15roll 39 and around an idler roll 40. Rolls 39 and 40 are mounted on a supporting c~lumn 41 with roll 39 dis-posed above roll 40 and both rolls 39 and 40 being dis-posed in substantially corresponding positions to rolls 36 and 37. Rolls 36 and 37 and 39 and 40 are free to rotate about their respective axes but are stationary in the sense that the axes do not move with respect to conve~ing path 4. In contrast, dancer roll 38 is both free to rotate about its axis and free to move its axis vertically, i.e., normal to the plane of conveying path 4 as seen in Fig. 1. To accomplish this, roll 38 is rotatably mounted on a shaft 42 and the shaft 42 is connected to a bracket 43 having a pair of projecting lugs 44 formed thereon, as seen in Fig. 2 The lugs 44 are spaced from one another and include openings formed therethrough which slidably receive a pair of vertically extending support poles 45 Thus, dancer roll 38 i5 free to move vertically, as seen in Fig. 1, on poles 45, the purpose of which will hereinafter be descr:ibed.

~;2Q367i~

After passing around idler roll 40, sheet 1 passes over another idler roll 46. As seen in Fig. 2, roll 46 is rotatably mounted between a pair of arms 47 which extend from the downstream end of a work table 48 and is utilized to position sheet 1 at the same level as work table 48.
The set 7 of drive rolls located downstream from idler roll 46 operates as a means for driving the sheet 1 of filter material over work table 48. As best seen in Figs. 3 and 4, the set 7 cf drive rollers includes a lower roll 49 and an upper roll 50 mounted on respective shafts 51 and 52 extending transversaly with respect to sheet 1. As seen bes-t in Fig. 4, shaft 52 of upper roll 50 is journaled at its opposite ends in a pair of lS bearing blocks 53 (only one of which is shown). Each bearing block 53 is slidably mounted for vertical movement on a p~ir of support members ~4. A pair of springs 55 encircle the shank portions of each support member 54 and bear against the bearing block 53 to force the bearing block 53 downwardly toward work table 48O Thus, upper roll 50 is spring-loaded and will maintain a downward force against the upper surface of sheet 1 so that sheet 1 may be frictionally engaged by the lower roll 43, which is the driving roll.
2S As seen best in Fig. 3, shaft Sl of lower roll 49 comprises the output shaft of a gear box 56. The input to gear box 56 is connected to any conventional power source appropriate for driving roll 49. The other end of shaft 51 is journaled in a bearing 57 which is supported under table 48. The free end of shaft Sl projects through bearing 57 and includes a brake disc 58 connected thereto which rotates with shaft 51. A pair of brake disc pads 59 are positioned on opposite axial sides of the periphery of disc 58. The pads 59 are actuated by a hydraulic cylinder connected through hydraulic line 60 _g_ ~3i~7~3 to engage or squeeze the opposite sides of disc 58 when it is desired to stop sheet 1. The brake pads 59 are mounted on a plate 61 by means of bolts 62 extending therethrough and the plate 61 is in turn mounted to the bearing 57 by means of bol~s 63. Thus, the pads i9 and disc 58 act as,a stopping means for positively stopping drive roll 49 at a desired time. The stopping of drive roll 49 in turn positively stops the sheet 1 of the filter material since the sheet 1 is engaged in the nip formed hetween rolls 49 and 50. Thus, sheet 1 may be positively stopped to per~orm,the transverse joining and cutting operations, which will now be des-cribed.
An ultrasonic horm 64 located downstream from the set 7 of drive rolls together with its corresponding ~nvil 65 is utilized as a means for joining or bonding the sheet 1 in a transverse direction. As shown best in Fig. 6, the ultrasonic horn 64 is mounted on a carriage-66 to slidably reciprocate in a transverse direction across the width of sheet 1. The carriage 66 includes an inverted U-shaped frame 67 which is mounted on a slide 68 located beneath work table 48. Ultrasonic horn 64 is mounted in a depend~ng fashion from the crossbar portion,of frame 67 so that its nozzle is located dLrectly above sheet 1 and closely spaced therefrom. 51ide 68 includes two pairs of spaced lugs 69 depending from i~s undersurface. Each lug 69 includes an opening formed therethrough for receiving a crossbar 70 which in turn is supported at,its opposite ends by a pair of trunions 71. The carriage 66 is connected to the rod ends of a ,barrel'ca~i feedex 7~ and thus upon actuation of the ~rive ,motor for feeder 72 the carriage 66 and ultrasonic,horn 64 will reciprocate to the left-an~ rightr as shown in.Fig~ 6, with the result tihat horn 64 will~move across the width o~ sheet 1 to trans~ersely bond or w21d the overlying web portions of sheet`l. As is obvious, other means for moving the carriage 66 and horn 64 might also be used.

3L2~367~3 As the ultrasonic horn 64 moves across the top surface of sheet 1, the anvil 65 moves across the under-surface of sheet 1. Anvil 65 is knurled so that as the fibers in the bonded area are fused together the knurling provides the bonded areas with a series of alternate depressions and projections thereby increaseing the surface area to enhance the bond between the web portions of sheet 1. As seen best in Fig. 5, anvil 65 is in the form of a rotatable wheel member with its knurled periphery closely adjacent the undersurface of sheet 1. In order to accommodate the periphery of anvil 65 the work table 48 has a transverse slot formed therein, as best seen in Fig. 5. Anvil 65 is mounted ~or rotation on the output shaft 73 of gear box 74 which in turn is connect~d to a rack 75 through a pinion 76, and is mounted to the under-surface of slide 68. Thus, when slide 68 is moved trans-ver.sely, it rotates pinion 76 which in turn rotates shaft 73 and anvil 65 through the gear train contained in gear box 74. Thus, the knurled periphery of anvil 65 will follow the movement of ultxasonic horn 64 across sheet 1.
Cutting means for transversely cutting sheet 1 is also provided. As shown in Fig. 5, the cutting means includes a cutting disc 75 mou.nted coaxially with anvil 65 on shaft 73 for rotation therew.ith. As the anvil 65 rotates the cutting disc 75 tran5vexsely cuts sheet 1 at a location adjacent to the transverse joint formed by ultrasonic horn 64. It is important that the cut be formed at a location closely adjacent to the transverse bonding area of sheet 1. The vibration of sheet 1 caused by ultrasonic horn 64 during welding enables the cutting disc 76 to cut cleanly through sheet 1 without any torn or jagged edges.
The cutting means also includes a clamping means for clamping the sheet 1 adjacent the transverse cut on the upstream and downstream sides thereof in order 3~

to aid in obtaining a clean cut. This clamping means is provided by a pair of clamp members 76 which engage the upper surface of sheet 1 on the opposite sides of the transverse slot formed in table 49, as seen best in Fig. 5. Each clamp member 76 includes an inver~ed U-shaped supporting frame 77 and a cross bar member 78 extending between the legs of frame 77, as seen best in Fig. 6. Each clamp member 76 also includes a hydraulic cylinder 79 mounted on frame 77 having its rod end connected to cross bar member 78. Thus, upon acutation o-f cylinder 79 cross bar member 78 moves normal to the plane of sheet 1 to either engage and hold sheet 1 firmly against work table 48 while the transverse welding and cutting operations take place, or disengage from sheet 1 to enable drive roll 49 to advance sheet 1 to the right as shown in Fig. 5. The clamping action of membe~ 78 also causes the undersurface of sheet 1 to be pressed against the knurled periphery of anvil 65 so that ultrasonic horn 64 may create a strong bond.
As the transverse cutting and weldingoperations take place, the opposite or free end of sheet 1 is held a~ainst a belt conveyor 80 by means of a hold-down roll 81. Roll 81 is supported by a pair of vertical support membexs 82 mounted on the supporting structure of conveyor 80 t and a cross-bar portion 83 extending between the members 82 above conveyor 80. Roll 80 is rotatably mounted between the legs of a bail member 84 which in turn is connected to the cross-bar portion 83 by a rod 85. A spring 86 encircles rod 85 and extends between bail member84 and cross-bar portion 83 to apply a downward force on roll 81. Roll 81 -thus engages the free end of sheet 1 and forces it against the belt of conveyor 80. After sheet 1 has been transversely bonded and cut, conveyor 80 is driven to discharge what has now become a completed filter sock 87, as shown in ~ig. 7 7~3 ~

Conveyor 80 is driven at a faster speed than sheet 1 so that the sock 87 may be cleanly taken away from work table 48 and transported ~o a packaging station.
Fig. 7 shows the completed filter sock 87.
The sock 87 is composed of a longitudinally folded shee~
88 of spun bonded, randomly oriented, continuous synthetic fibers, such as polyester fibers. The free longitudinal edges of the sheet are bonded together by an ultrasonic bond 89, while the adjacent end edges are bondedtogether by a transverse ultrasonic bond 90 to provide the open end tubular construction.
In operation, the sheet 1 of filter material is continuously fed from its StQrage drum 2 through folder 3 which longitudinally folds the sheet 1 into two overlying weh portions. The upper free longitudinal edge of sheet 1 is then scuffed by scuffer 19 and as the sheet 1 is conveyed downstream along path 4 the vacuum nozzle 24 picks up any lint particles created by scuffer 19. Sheet 1 is then guided by member 11 into the nip formed bet~een the set 5 of drive rolls. The sheet 1 is then fed to the ultrasonic horn 17 which con-tinuously joins or bonds the adjacent free longitudinal edges of the overlying web portions o~ sheet 1 as sheet 1 is conveyed along path 4. Sheet 1 is then driven by the set 6 o drive rolls over tension roll 27 and around idler rolls 36 and 37 to dancer roll 38.
As the sheet 1 is being continuously fed to dancer roll 38, the set 7 of drive rol~s located down-stream therefrom is being intermittently started and stopped to advance sheet 1 over work table 48 to perform the transverse bonding and cutting operations. The set 7 o drive rolls intermittently advances ~he sheet 1 only a distance equal to the length of sock desired. Upon advancing sheet 1 the desired distance, the brake pads 59 engage brake disc 58 to positively stop sheet 1 at the ~2~36~8~

desired position. This ensures that each sock 87 has the precise length desired. When sheet 1 is stopped, ul-trasonic horn 64 and cutting disc 75 move across the width of shee~ l to transversely bond and cut the sheet 1 at substantially the same time.
After the bonding and cutting operation, the brake pads 59 are released from brake disc 58 and drive roll 49 once again advances the sheet 1 only the desired di.stance required to perform the bonding and cutting operations for the ne~t filter sock.
While the downstream end of sheet 1 is stopped during the bonding and cutting operations, the upstream end of sheet l is being continuously fed by the sets 5 and 6 of drive rolls. Thus, in order to take up the lS slack which would otherwise be created or to acc~mulate the sheet 1~ dancer roll 38 moves from the position shown in phantom lines in Fig. 1 to the posi~ion shown in solid lines in Fig. 1 by means of the force of gravity. Dancer roll 38 thus slides downwardly which will take up the slack or accumulate sheet 1 while its downstream end is stopped. When the downstream end o sheet 1 is advanced by the set 7 of drive rolls, dancer roll 38 will move upwardly back to the position sub-stantiall~ shown in phantom lines in Fig. 1. Thus, dancer roll 38 continuously reciprocates between its upper and lower positions as the sheet 1 is advanced through the apparatus.
Ater the transverse bonding and cutting operations have been perform~d, the sheet l of filter material has been transformeZ into a filter sock having the open end t~ular construction, and is discharged from work table 48 onto a conveyor 80 which is driven at a faster speed than the sheet 1 is advanced by the set 7 of drive rolls so that the filter sock 87 may be quickly removed and transported to a packaging area.

~~ - ~
~36~

A method and apparatus for making milk filter socks for use in pipeline milking systems has been shown and described. The method and apparatus includes means at its upstream end for ccntinuously feeding a longitudinally folded sheet of filter material along a conveying path and means for bonding the free longitudinal edges as the sheet is conveyed along the path. There is also included a means for intermittently stopping the downstream end of the filter material during which time the sheet is transversely bonded and cut to form an open end tubular construction. An accumulating means accumulates the upstream end of the sheet of filter material which is being continuously fed while the downstream end of the sheet is stopped to perform the transverse bonding and cutting operations.

~0 ~5 -lS-

Claims (18)

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. Apparatus for making filter socks, com-prising:
feeding means for continuous feeding a sheet of filter material along a conveying path, said sheet having a pair of overlying web portions;
first joining means for joining the adjacent free longitudinal edges of said overlying web portions as said sheet is conveyed along said path;
stop means located downstream from said first joining means for intermittently stopping the sheet of filter material;
second joining means for transversely joining said web portions while said sheet is stopped;
cutting means for transversely cutting said web portions at a location adjacent to the transverse joint formed by said second joining means; and accumulating means located between said first and second joining means for accumulating the sheet of filter material being fed from said feeding means while the downstream end of said sheet is stopped by said stop means.

2. The apparatus of claim 1, wherein said feeding means includes a drive roll engaging said sheet and located upstream from said first joining means.

3. The apparatus of claim 2, wherein said feeding means includes an adjustable guide means located upstream from said drive roll for transversely adjusting the position of said sheet.

4. The apparatus of claim 1, wherein said feeding means includes folding means located upstream from said first joining means for longitudinally folding the sheet of filter material to form said overlying web portions.

5. The apparatus of claim 1, further including scuffer means located upstream from said first joining means for scuffing the surface of the filter material along the longitudinal edge margin of one of said web portions.

6. The apparatus of claim 5, further including vacuum means located adjacent to and downstream from said scuffer means for removing lint particles from the surface of the filter material created by said scuffer means.

7. The apparatus of claim 1, wherein said first joining means includes a knurled anvil engaging one side of said sheet, and an ultrasonic welder positioned on the opposite side of said sheet.

8. The apparatus of claim 1, wherein said cutting means includes a cutting blade positioned on one side of said sheet, reciprocating means for transversely reciprocating the cutting blade against said sheet, and clamping means for clamping said sheet adjacent the transverse cut on the upstream and downstream sides thereof.

9. The apparatus of claim 8, wherein said second joining means includes a knurled anvil engaging said one side of said sheet adjacent the cutting blade, and an ultrasonic welder postioned on the other side of said sheet between said clamping means.

10. The apparatus of claim 9, wherein said cutting blade is a rotatable cutting disc, said anvil is a rotatable wheel member mounted coaxially with said cutting disc for rotation therewith, and said recipro-cating means includes a rack and pinion arrangement.

11. The apparatus of claim 1, further including a drive roll located downstream from said accumulating means and upstream from said second joining means, and said stop means includes brake means for engagement with said drive roll to prevent its rotation.

12. The apparatus of claim 1, wherein said accumulating means includes a dancer roll engaging one side of said sheet, said dancer roll being slidably mounted for reciprocal movement in a direction normal to the plane of the conveying path.

13. A method of making filter socks, com-prising the steps of:
continuously feeding a sheet of filter material having a pair of overlying web portions along a conveying path;
continuously joining the adjacent free longi-tudinal edges of the overlying web portions as said sheet is conveyed along said path;
intermittently stopping the sheet of filter material at a location downstream from where said longitudinal edges are joined;
joining the overlying web portions in a transverse direction while said sheet is stopped;
cutting the overlying web portions in a trans-verse direction at a location adjacent to the transverse joint while said sheet is stopped; and accumulating the sheet of filter material being continuously fed along said path while said sheet is stopped.

14. The method of claim 13, wherein the steps of joining the overlying web portions in a transverse direction and transversely cutting the web portions take place at substantially the same time.

15. The method of claim 13, further including the step of longitudinally folding the sheet of filter material to form the overlying web portions as said sheet is fed along the conveying path.

16. The method of claim 13, further including the step of scuffing the longitudinal edge of one of said web portions prior to joining said longitudinal edges.

17. The method of claim 16, further including the step of vacuuming the surface of said one web portion after scuffing but prior to joining the longitudinal edges.

18. The method of claim 13, further including the step of clamping the sheet of filter material adjacent the transverse cut on the upstream and downstream sides thereof prior to cutting.