Technical Field

The present invention relates to sewing machines, and in particular, sewing machines that lack a bobbin.

Background of the Invention

The maximum amount of thread that can be stored on the bobbin for a lock stitch sewing machine, be it used for sewing or embroidery, is extremely limited due to its geometric conditions. The amount of thread that can be stored within the lower bobbin covers only a fraction of what is available to the upper needle. Therefore, the lower bobbin is in constant need of refilling. The present invention addresses this problem.

Brief Summary of Embodiments of the Invention

A bobbin system for a sewing machine, comprises: an inner bearing; a hook configured to rotate or oscillate, formed as part of the inner bearing; an outer bearing, attachable to a chassis of the sewing machine and attached to the inner bearing; rolling elements connecting the inner bearing to the outer bearing; an interior void traversing the inner bearing, leading to the hook; and a drive mechanism, connected to the inner bearing.

In a variant, a stationary thread feed tube is disposed in the interior void, configured as a conduit for thread leading to the hook and configured to remain stationary while the hook rotates or oscillates.

In another variant, the drive mechanism is driven by teeth located inside or outside or fore or aft of the inner bearing.

In a further variant, an exit end of the thread feed tube is open and the thread extends into a thread tension case.

In yet another variant, the inner bearing has a shaped portion to provide a cavity for the reception of a thread tension case holder

In still a further variant, a thread tension case holder has a circumferentially extending rib, having an interrupted region to allow the thread tension case holder to be inserted into the inner bearing.

In a variant, a recessed raceway that conforms to the rib, wherein the raceway extends through a circumference of a wall of the inner bearing. The raceway is formed in a wall of the inner bearing and is closed at an outer side via a gib retainer. The gib retainer has an inwardly extending flange which forms an outer wall of the raceway. In another variant, a peripheral surface of the rib cooperates with an inwardly facing surface of the raceway formed in the inner bearing.

In a further variant, a brace having a mandrel centrally placed therein for receiving a thread tension case, the mandrel having a locking point.

In yet another variant, the brace has a cut out for receiving the thread feed tube.

In still a further variant, the thread feed tube extends no further than the locking point of the mandrel.

In a variant, the thread feed tube has a flat recess cut out on a outer side of a rear of the thread feed tube so that it can be clamped in place.

In another variant, the thread feed tube has a cut out at one end to create a channel to guide thread and allow the thread to slip smoothly into a thread tension case.

In a further variant, the inner bearing has an inwardly extending flange on an inner wall of the raceway, the flange extending from a point adjacent to a beak of the hook to a point adjacent a forward end of an insert. The closed outer side of the raceway extends from a rearward end of the insert and from a thread catchment point of the gib.

In yet another variant, of the bobbin system, a thread guard, has a rearward end positioned adjacent the beak of the hook, and has an outwardly projecting portion comprising a thread catchment point. A void is formed between a notch and the beak of the hook, the void providing for the passage of a downward passing needle. A forward end of the thread guard extends to a position adjacent the hook beak.

By changing the operation of the main hook body from rotating or oscillating off of a shaft, to being operated via a bearing. The outer bearing is secured to the chassis of the lock stitch machine. The inner bearing is integrated as part of the main hook body. By way of this arrangement, this now allows for the creation of a void on the inside of the main hook body. Within this void it is now possible for the lower thread to pass through the void by means of a tube to the feed the thread directly to a tension case, ready to form the lower locking stitch.

In the present invention there is provided a bobbinless system for feeding the lower thread of a sewing machine. The bobbinless system comprises an outer bearing main hook body that is placed within a seat which is attached to the chassis of a sewing machine. The seat allows the outer bearing main hook to oscillate or rotate within the seat along a fixed path. The outer bearinghook body is driven by gear teeth that can be located fore or aft of the main hub. Within the void of the outer bearing main hook body is placed an inner bearing spindle which has a hollowed core with an exit point at one end allowing the lower thread to pass freely through the core of the spindle, thus removing the need for the bobbin.

Therefore, an aspect of some embodiments of the present invention relates to a threadfeeding system for a sewing machine, comprising a retainer, an outer bearing hook body, a hollow inner bearing spindle, and rolling elements. The retainer is configured for being joined to a chassis of the sewing machine. The outer bearing hook body comprises a hook and is joined to the retainer, such that the outer bearing hook body is configured to rotate or oscillate along a fixed path within the retainer, thereby causing the hook to rotate or oscillate. The hollow inner bearing spindle has an exit hole on a side thereof, the inner bearing spindle being configured for being traversed by a thread and for leading the thread to the hook via the exit hole. The rolling elements connect the inner bearing spindle to the outer bearing hook body and are configured to enable coaxial rotation of the outer bearing hook body with respect to the inner bearing spindle.

In a variant, the inner bearing spindle is configured to remain stationary while the hook rotates or oscillates.

In another variant, the outer bearing hook body comprises gear teeth, the gear teeth being configured to cooperate with a gear of a driving mechanism of the sewing machine, such that the driving mechanism is configured for causing the outer bearing hook body to rotate or oscillate.

The gear teeth may be located inside or outside of the outer bearing hook body, and on a fore section or an aft section of the outer bearing hook body.

In yet another variant, the outer bearing hook body has a shaped portion to provide a cavity for the reception of a thread tension case holder.

In a further variant, the above -described thread-feeding system includes a thread tension case holder having a radially extending rib, having an interrupted region to allow the thread tension case holder to be inserted into the outer bearing hook body.

Optionally, the thread-feeding system includes a recessed raceway that conforms to the rib, wherein the raceway extends through a circumference of a wall of the outer bearing hook body. The raceway is formed in a wall of the outer bearing hook body and is closed at an outer side via a gib retainer. The gib retainer has an inwardly extending flange which forms an outer wall of the raceway.

The peripheral surface of the rib may cooperate with an inwardly facing surface of the raceway formed in the outer bearing hook body.

In yet a further variant, the inner bearing spindle has a recess cut out on an outer side of a rear of the inner bearing spindle, the recess being configured to cooperate with a holding unit joined to a chassis of the sewing machine, so that the inner bearing spindle can be clamped in place and held fixed with respect to the sewing machine.

In a variant, the thread feeding system further comprises a curved thread guard configured for matching a shape of and being joined to an outer surface of the outer bearing hook body, the thread guard having a first end adjacent a beak of the hook and having a second end having an extension along a curve of the thread guard forming a thread catchment point. A void is formed between the first end of the thread guard and the beak of the hook, the void providing for the passage of a downward passing needle of the sewing machine.

In another variant, the spindle is sealed at a fore end thereof and comprises a locking groove configured to cooperate with a tension case and for holding the thread tension case in a desired position with respect to the sewing machine.

Optionally, the locking groove is a circumferential recess around the fore end of the spindle.

In an variant, the thread tension case holder comprises a protrusion extending radially outward, the protrusion being configured to cooperate with a detaining finger of the sewing machine to prevent rotation or oscillation of the thread tension case holder while the outer bearing hook body rotates or oscillates.

Another aspect of some embodiments of the present invention relates to a sewing machine comprising the thread feeding system described above.

A thread tension case for bobbinless systems for feeding thread for any sewing or embroidery machine that requires a locking stitch is provided. Thread delivered by the thread feeding system is passed into the inside of the thread tension case of the present invention, where it is guided by a spring clip (under tension) to pass into a chamfer on the side of the thread tension case and is held in place by a thread tension spring. The thread then exits the thread tension case and is ready for the formation of the lower locking stitch of the lock stitch sewing machine. The thread tension case operates to create the correct amount of drag and resistance for the lower thread in the formation of the lower locking stitch.

Therefore, an aspect of some embodiments of the present invention relates to a thread tension case configured for being joined to a bobbinless lower thread feeding system of a sewing machine and creating drag and resistance for a lower thread during formation of the lower locking stitch. The thread tension case comprises a cylindrical wall, a cap, a thread tension spring, a spring, a pin lock, and a finger latch. The cylindrical wall surrounds a hollow space, and has a first end and a second end, the second end being capped. The cylindrical wall has a gap configured for enabling a needle of the sewing machine to enter the hollow space. The cylindrical wall has a chamfer configured for being traversed by the lower thread, the chamfer extending in an angular incline along the wall and turns sharply before terminating in a termination point. The cap caps the second end and has a middle hole at the middle of the cap. The cap includes an inner shaft, a first protrusion, a second protrusion, a first channel, and a second channel. The inner shaft surrounds at least part of a circumference of the hole and extends into the hollow space within the cylindrical wall. The first protrusion is located on a bottom section of an outer surface of the cap facing away from the hollow space. The second protrusion is located on a top section of the outer surface of the cap. The first channel is carved in the first protrusion, extends sideways along the outer surface of the cap, and faces the second protrusion. The second channel is carved in the second protrusion, extends sideways along the outer surface of the cap, and faces the first protrusion. The thread tension spring comprises a curved elongated sheet having a first edge joined to the cylindrical wall and a second edge opposite to the first edge being free of the cylindrical wall. The elongated sheet has a curvature set to match a first curvature of the cylindrical wall. The thread tension spring covers part of the chamfer and the termination point. The spring is configured for being located in one of the first channel or the second channel. The pin lock comprises a flat slide and a locking hole. The flat slide extends along a first plane and is configured for being inserted into the first and second channels and for being slid along the surface of the cap within the first and second channels. The flat slide comprises a top a spring jam extension extending upwards or downwards along the first plane, the spring jam extension being configured for contacting one end of the spring within the first or second channel. The locking hole is located at or near a middle of the slide. The finger latch has an end removably joined to the pin lock and configured for being located on an outer surface of the slide and for cooperating with the pin lock, so that lifting the finger latch from the pin lock causes finger patch to rotate with respect to the pin lock and causes the pin lock to slide sideways to align the middle hole of the cap with the locking hole of the slide, to enable a pin of the lower thread feeding system to be inserted into the thread tension case.

In a variant, the cap comprises a first latch insertion hole located laterally to the middle hole, the first latch insertion hole having an outer end facing the edge of the cap and an inner end facing the center of the cap, the inner end of the first latch insertion hole being wider than the rest of the first latch insertion hole. The slide comprises a second latch insertion hole shaped to match a shape of the first insertion hole. The finger latch comprises a planar panel and a curved extension. The planar panel extends along a second plane. The curved extension extends away from a side of the planar panel and curves away from the second plane, the curved extension having a head located at an edge of the curved extension, the head having a top-to-bottom width larger than a maximal top-to-bottom width of the curved extension. The finger latch, the slide, and the cap are joined together by inserting the head of the finger latch into the wider ends of the first and second latch insertion holes and rotating the finger latch so that the head is pushed radially outward to the narrower ends of the first and second latch insertion holes.

In another variant, the thread tension spring is removably joined to the cylindrical wall.

In yet another variant, the cylindrical wall comprises a first screw opening. The thread tension spring comprises a second screw opening aligned with the first screw opening. The thread tension case comprises an adjustment screw configured to traverse the first and second screw openings, and for being tightened to decrease the distance of the free edge from the cylindrical wall and being loosened to increase the distance of the free edge from the cylindrical wall.

In a further variant, the thread tension spring comprises an inwardly depressed rib at the free edge, the inwardly depressed rib is configured for touching the cylindrical wall when no thread is located between the cylindrical wall and the thread tension spring.

Optionally, a delivery slot is cut in the cylindrical wall to receive the inwardly depressed rib.

In yet a further variant, the inner shaft has a perforation on a side thereof.

In a variant, a window is cut on the first or second protrusion, to allow access to the lower thread. In another variant, the thread tension case comprises a curved spring clip located in the hollow space and has a first spring clip end joined to an outer surface of the inner shaft and a second spring clip end joined to an inner surface of the cylindrical wall. The spring clip is configured for guiding the lower thread from an exit point of the thread feeding system to the chamfer.

Optionally, the spring clip is removable from the inner shaft and the cylindrical wall.

In yet another variant, the pin lock comprises a neck extending from a lateral side of the slide and curving away from the first plane of the slide. The cap comprises a neck insertion hole on a lateral side of the cap, the neck insertion hole extending to an edge of the cap and along part of the cylindrical wall. When the finger latch, lock pin, and cap are joined together and the finger latch lies on top of the lock pin’s slide, the neck extends over a circumference of the cylindrical wall. When the finger latch, lock pin, and cap are joined together and the finger latch lies is rotated away from the lock pin’s slide, the neck is drawn inside the neck insertion hole.

In a further variant, the first protrusion together with the finger latch and the second protrusion form a convex surface configured to assist in the casting and the smooth passing of an upper lock stitch thread as the upper lock stitch thread glides over the surface to catch the lower thread to form a locking stitch.

In still another variant, a thread tension case comprises a cylindrical wall surrounding a hollow space and has a sealed end. The cylindrical wall has a gap configured for enabling a needle of the sewing machine to enter the hollow space. The cylindrical wall has a chamfer configured for being traversed by the lower thread. A thread tension spring generates resistance to a lower thread of the sewing system. A spring is configured for being located in one of the first channel or the second channel. A pin lock holds the tension case in position. A finger latch allows for insertion or removal of the tension case from the sewing system.

In another variant, the thread tension case has a slide with an extended neck that locks the tension case into position and the neck preventing rotation.

In a further variant, the tension case has a pin and the cylindrical wall functions as a sleeve over the pin in the tension case holder.

In yet another variant, the cylindrical wall forms a C shape in cross section.

In still a further variant, the tension case has a spring clip for guiding thread to the chamfer.

Brief Description of the Drawings

The present invention, in accordance with one or more various embodiments, is described in detail with reference to the following figures. The drawings are provided for purposes of illustration only and merely depict typical or example embodiments of the invention. These drawings are provided to facilitate the reader’s understanding of the invention and shall not be considered limiting of the breadth, scope, or applicability of the invention. It should be noted that for clarity and ease of illustration these drawings are not necessarily made to scale.

Some of the figures included herein illustrate various embodiments of the invention from different viewing angles. Although the accompanying descriptive text may refer to such views as“top,”“bottom” or “side” views, such references are merely descriptive and do not imply or require that the invention be implemented or used in a particular spatial orientation unless explicitly stated otherwise.

Fig. 1 is an exploded view of a first bobbinless thread-feeding system, according to some embodiments of the present invention;

Fig. 2 is a front view of the bobbinless thread-feeding system of Fig. 1 ;

Fig. 3 is a side view of a thread feed tube of the bobbinless thread-feeding system of Fig. 1 ;

Fig. 4 is a top view of the thread feed tube of the bobbinless thread-feeding system of Fig. 1 ;

Fig. 5 is a sectional view of the thread feed tube of the bobbinless thread-feeding system of Fig. 1 ;

Fig. 6 is a side view of the bobbinless thread-feeding system of Fig. 1 ;

Fig. 7 is a side cross sectional view of the bobbinless thread-feeding system of Fig. 1 ;

Fig. 8 is a perspective view of an inner bearing hook main body hub of the bobbinless thread-feeding system of Fig. 1, with teeth located on its inner surface;

Fig. 9 is a cross section view of an inner bearing hook main body hub the bobbinless thread-feeding system of Fig. 1, with teeth located on its inner surface and drive mechanism;

Fig. 10 is an exploded view of a second bobbinless thread-feeding system, according to some embodiments of the present invention;

Fig. 11 is a side view of the bobbinless thread-feeding system of Fig. 10, according to some embodiments of the present invention;

Fig. 12 is a cross-sectional side view of the bobbinless thread-feeding system of Fig. 10, according to some embodiments of the present invention;

Fig. 13 is a side view of the spindle of the bobbinless thread-feeding system of Fig. 10, according to some embodiments of the present invention;

Fig. 14 is a cross-sectional side view of the spindle of the bobbinless thread-feeding system of Fig. 10, according to some embodiments of the present invention; Fig. 15 is a side view of the outer bearing hook body of the bobbinless thread-feeding system of Fig. 10, according to some embodiments of the present invention;

Fig. 16 is a perspective view of the thread tension case holder of the bobbinless thread-feeding system of Fig. 10, according to some embodiments of the present invention;

Fig. 17 is a cross-sectional side view of the outer bearing hook body and its connection to the thread tension case holder of the bobbinless thread-feeding system of Fig. 10, according to some embodiments of the present invention;

Fig. 18 is a front view of the thread tension case holder of the bobbinless thread-feeding system of Fig. 10, according to some embodiments of the present invention;

Fig. 19 is a perspective view of an outer bearing hook body of the bobbinless thread-feeding system of Fig. 10 having gear teeth extending radially inwards on its inner surface, according to some embodiments of the present invention;

Fig. 20 is a perspective view of an outer bearing hook body of the bobbinless thread-feeding system of Fig. 10 having gear teeth located fore of the rib connecting the outer bearing hook body to the retaining seat, according to some embodiments of the present invention;

Fig. 21 is a side view of the bobbinless thread-feeding system of Fig. 10 before being joined to the chassis of a sewing machine, according to some embodiments of the present invention;

Fig. 22 is a side view of the bobbinless thread-feeding system of Fig. 10 joined to the chassis of a sewing machine, according to some embodiments of the present invention;

Fig. 23 is a top view of the bobbinless thread-feeding system of Fig. 10 joined to the chassis of a sewing machine, according to some embodiments of the present invention;

Fig. 24 is a front view of the bobbinless thread-feeding system of Fig. 10 joined to the chassis of a sewing machine, according to some embodiments of the present invention;

Fig. 25 is a perspective view of a clamp for holding the spindle of the bobbinless thread-feeding system of Fig. 10;

Fig. 26 is a front view of a clamp of Fig. 25;

Fig. 27 is an exploded perspective three-quarters view of a thread tension case configured to be joined to the system of Fig. 1 or Fig. 10, according to some embodiments of the present invention;

Fig. 28 is a perspective three-quarters view of the thread tension case of Fig. 27, illustrating the front and a side of the thread tension case;

Fig. 29 is a front view of the thread tension case of Fig. 27 ; Fig. 30 is a perspective three-quarters view of the thread tension case of Fig. 27, illustrating the back and a side of the thread tension case; and

Fig. 31 is a rear view of the thread tension case of Fig. 27.

The figures are not intended to be exhaustive or to limit the invention to the precise form disclosed. It should be understood that the invention can be practiced with modification and alteration, and that the invention be limited only by the claims and the equivalents thereof.

Detailed Description of the Embodiments of the Invention

From time-to-time, the present invention is described herein in terms of example environments. Description in terms of these environments is provided to allow the various features and embodiments of the invention to be portrayed in the context of an exemplary application. After reading this description, it will become apparent to one of ordinary skill in the art how the invention can be implemented in different and alternative environments.

The following reference numerals are used throughout this document:

21 Main Hook Body Inwardly Extending

1 Outer Bearing

Flange

2 Bracing Point

22 Main Hook Body Beak

3 Outer Bearing Recess

23 Insert

4 Ball Bearings

24 First Thread Guard

5 Ball Cage

25 Notch

6 Inner Bearing Hook Main Body

26 First Thread Catchment Point

7 Inner Bearing Hook Main Body Hub

27 First Gear Teeth

8 Inner Bearing Hook Body Cutout

28 Thread Feed Tube Cut Out

9 First Thread Tension Case Holder

29 Flat Recess

10 Thread Tension Case Holder Rib

30 Drive mechanism

11 Interruption

31 First Indentation

12 Notch

101 Outer Bearing Retaining Seat

13 Vertical Brace 102 Bracing Points

14 First Horizontal Pin

103 Recessed Raceway

14a Circumferential Recess

104 Rib

15 Cut Out

105 Outer Bearing Hook Body

16 Thread Feed Tube

106 Retaining Gib

17 Inner Bearing Hook Body Recessed

107 Screws

Raceway

108 Hub Portion

18 Gib Retainer

109 Ball Bearings

19 Screws

110 Riveted Cage

20 Gib Retainer Flange

111 Cutout Second Thread Tension Case Holder 150 Sewing Machine Chassis Recessed Raceway 152 Sewing Machine Needle First Beak 200 Holding Unit

Insert 202 Gripper

Flange 204 Tightening Screw Retaining Gib Member 206 Holding Unit’s Base Raceway Retaining Point 208 Screws

Second Thread Guard 300 Thread tension case Second Thread Catchment Point 302Cylindrical Wall Second Beak 304 Cap

Circumferentially Extending Rib 306 First Protrusion

Interrupted Region 307 Spring Insertion Slot Extension/Notch 308 Second Protrusion Second Gear Teeth 310 Hole

Inner Bearing Spindle 312 Inner Shaft

Main Hub Portion 314 Gap

Second Horizontal Pin 318 Chamfer

Locking Groove 320 Thread Tension Spring Exit Hole 322 Termination Point Flat Recess 324 Screw

Thread 326 First Screw Opening Second Indentation 328 Tension Adjustment Screw Thread-Feeding System 330 Second Screw Opening 332 Inwardly Depressed Transverse Rib 502 Slide

334 Delivery Slot 506 Spring Jam Extension

335 Lirst Latch Insert Opening 504 Neck

336 Neck Insertion Hole 508 Locking Hole

338 Window 510 Latch Insertion Hole

340 Lirst Locking Point Groove 600 Linger Latch 342 Lirst Locking Point Groove 602 Planar Panel 344 Spring Clip 604 Curved Extension 400 Spring 606 Head

500 Horizontal Pin Lock

Ligs. 1-9 refer to a first thread feeding system for a sewing machine, according to some embodiments of the present invention. Ligs 10-26 refer to a second thread feeding system for a sewing machine, according to some embodiments of the present invention. Ligs. 27-31 refer to a thread tension case configured for being joined to and used with the first thread feeding system or the second thread feeding system, according to some embodiments of the present invention.

Lirst Thread Leeding System

A first thread system for a sewing machine is described. The first thread system may be used as a high- velocity system. Referring to Lig. 1, an outer bearing 1 has bracing points 2 for securing the outer bearing 1 to the chassis of the sewing machine. The outer bearing 1 has a recess 3 for the placement of ball bearings 4 or rollers, held in place by a riveted ball cage 5 or any other suitable means. An inner bearing has a main body 6, having a hub portion 7 by which the body may be secured to the outer bearing 1. The bearing 1 may comprise of ball bearings 4 or rollers, held in place by a riveted ball cage 5 or any other suitable means. The inner bearing main body 6 has a top that is shaped, or a shaped portion, to provide an inner bearing hook body cavity cutout8, which is a cutout of the inner bearing hook main body for the reception of a thread tension case holder 9.

The thread tension case holder 9 has a circumferentially extending rib 10 which is interrupted 11 in a region to enable it to be inserted into the inner bearing main body 6. This interruption 11 in the rib 10 is in a region adjacent the top of the tension case holder 9. It is also adjacent to the notch 12 in its outer face which cooperates with a normal detaining finger (not shown) secured to the under surface of the machine chassis bed and below the usual stitch plate (not shown) of a sewing machine. In some embodiments of the present invention, the first tension case holder 9 includes a first indentation 31 on a side of its inner wall. The indentation is configured for cooperating with a tension case, as will be explained further below, in relation to Figs. 27-31. Optionally, the first indentation 31 is at the edge of the first tension case holder that is farthest from the inner bearing main body 6.

A detaining finger prevents rotation of the thread tension case holder by the frictional drag of the inner bearing main body 6. To the rear of the thread tension case holder 9 is located a vertical brace 13 where a first horizontal pin 14 is centrally placed for receiving a thread tension case (not shown). Below the first horizontal pin 14 on the vertical brace 13, is a cut out 15 for the passage of a thread feed tube 16. The rib 10 on the thread tension case holder 9 cooperates with a recessed raceway 17 which extends through the circumference of the wall of the inner bearing main hookbody 6 which defines the cavity. This raceway 17 is in part cut or otherwise formed directly in the wall of the inner bearing main hook body 6 and is in part closed at its outer side by means of a gib retainer 18. The gib retainer is secured by screws 19 to the wall of the inner bearing hook main body 6. The gib retainer 18 has an inwardly extending flange 20 which forms the outer wall of the raceway in the hook body. The peripheral surface of the rib 10 cooperates with the inwardly facing surface of the hook raceway 17 formed in the inner bearing hook body 6.

Below the first horizontal pin 14 on the vertical brace 13, is a cut out 15 for the passage of a thread feed tube 16. The rib 10 on the thread tension case holder 9 cooperates with a recessed raceway 17 which extends through the circumference of the wall of the inner bearing main hook body 6 which defines the cavity. This raceway 17 is in part cut or otherwise formed directly in the wall of the inner bearing main hook body 6 and is in part closed at its outer side by means of a gib retainer 18. The gib retainer is secured by screws 19 to the wall of the inner bearing hook main body 6. The gib retainer 18 has an inwardly extending flange 20 which forms the outer wall of the raceway in the hook body. The peripheral surface of the rib 10 cooperates with the inwardly facing surface of the hook raceway 17 formed in the inner bearing hook body 6.

The thread tension case holder 9 is held against any appreciable axil movement in relation to the inner bearing hook body 6 by the flange 20 and by a corresponding opposed inwardly extending wall. The gib retainer 18 may be secured to the inner race bearing hook by screws 19 or rivets, or by any other suitable means. The main body 6 has an integral inwardly extending flange 21 on the inner wall of the hook raceway. This flange extends from a point adjacent to the beak 22 of the hook to a point adjacent the forward end of the insert 23. As has been explained, another portion of the hook raceway 17 is closed at its outer side by the flange 20 of the gib member 18. This closed in portion of the raceway 17 extends from the rearward end of the insert of the inner bearing main hook body 6 to the main hook body beak 22. This point alsoextends into a region adjacent the hook beak 22 and the forward end of the thread guard 24 when attached to the inner bearing main hook body. Secured to the circumferential face of the inner bearing hook main body 6 is a thread guard 24. This may be secured in place by screws 19 or rivets or by any other suitable means.

The thread guard 24, at its rearward end, positioned adjacent to the region of the main hook body beak 22, to its opposite end, has an outwardly projecting portion which serves to function as a thread catchment point 26. A void is formed between notch 25 and the main hook body beak 22 provided in the rearward end of the thread guard 24. The void enables the passage of the downward passing needle (not shown) into cooperation with the hook at the appropriate time in the cycle of revolution of the inner bearinghook main body 6 which partially defines the notch 25. At its forward end, the thread guard 24 extends to a position 26 opposite to the hook beak 22 and cooperates by catching the loop formed by the upper thread as the needle withdraws from the void between the hook beak 22 and the notch 25. The thread guard 24 may be secured to the inner race bearing hook 6 by screws 19 or rivets, or by any other suitable means.

The inner bearing hook body 6 is driven by a gear mechanism off the main drive shaft of the machine. The teeth for the gear 27 of the inner bearing hook 6 may be located inside or outside, fore or aft of the of the inner bearing hook main body hub 7. Within the interior void of the inner rotary hook bearing 6, it is possible to feed the lower locking stitch thread through, inside of the inner rotary hook bearing 6, and feed the thread directly into a thread tension case (not shown) via a thread feed tube 16, eliminating the need for refillable bobbins.

The thread feed tube has a cut out 28 at one end to create a channel to guide the thread and allow the thread to slip smoothly into a thread tension case (not shown) at the required angle. The cutout may be formed by cutting half of the circumference away at about 3/8ths of inch or any other appropriate/suitable measurement and removing itfrom the tube. The thread feed tube extends no further than the locking point of the first horizontal pin 14 of the thread tension case holder 9. The thread feed tube 16 can be fixed in place at the cut out 15 of the vertical brace 13 which is part of the thread tension case holder 9. A flat recess 29 is cut out on the outer side of the rear of the thread feed tube 16so that it can be clamped in place to make sure the thread exits the thread feed tube at the correct angle, and therefore preventing any movement of the thread feed tube 16. The thread feed tube 16 is disposed in the void, and is configured as a conduit for thread leading to the hook and is configured to remain stationary while the hook rotates or oscillates.

In a variant, referring to Figs. 8 and 9, The inner bearing hook body 6 is driven by a drive mechanism 30 comprising a gear mechanism off the main drive shaft of the machine. The teeth for the gear 27 of the inner bearing hook 6are located in the inside of inner bearing hook main body hub. Referring to Fig. 9, a pinion gear 30 comes off of the main shaft of a sewing machine drives the gear 27. Within the interior void of the inner rotary hook bearing 6, it is possible to feed the lower locking stitch thread through, inside of the inner rotary hook bearing 6, and feed the thread directly into a thread tension case (not shown) via a thread feed tube 16, eliminating the need for refillable bobbins.

Second Thread Feeding System

According to some embodiments of the present invention, referring to Figs. 10-26, a second thread feeding system 100 of the present invention includes a retaining seat 101, an outer bearing hook body 105, an inner bearing spindle 126, and rolling elements 109 connecting the outer bearing hook body 105 to the inner bearing spindle 126. The retaining seat 101 has bracing points 102 for securing the system to the chassis of a sewing machine. The outer bearing retaining seat 101 is hollow and has a cylindrical inner wall with a recessed raceway 103 which extends through the circumference of the inner wall of retaining seat 101.

The outer bearing hook body 105 is configured for being inserted in the retaining seat 101, and has an outer wall which includes a cylindrical section having a rib 104 extending radially outward along a circumference of the outer bearing hook body 105. When the outer bearing hook body 105 is inserted into the retaining seat 101, the outer bearing hook body 105 is substantially concentric with the retaining seat 101 and the rib 104 cooperates with the recessed raceway 103. In this manner the outer bearing hook body 105 is retained by the retaining seat 101 and can be rotated or oscillated around the axis of the inner wall of the retaining seat 101.

The raceway 103 is in part cut into or otherwise formed directly in the inner wall of the outer bearing retaining seat 101. The retaining seat 101 is partially cut, in order to allow for the insertion of the outer bearing hook body 105, such that the raceway 103 of the retaining seat 101 does not fully loop around the inner wall of the retaining seat. The missing portion of the retaining seat is closed at its outer side by means of a retaining gib 106, which can be mounted on the retaining seat after the outer bearing hook body 105 is inserted into the retaining seat 101. The retaining gib 106 has a flange extending radially inward towards the central axis of the cylindrical inner wall of the retaining seat 101, and has a carving of the inner side thereof that completes the loop of the raceway 103 when the gib 106 is joined to the retaining seat 101. In this manner, the gib 106 guarantees that the outer bearing hook body 105 rotates or oscillates along a fixed path within the retaining seat 101, without wobbling or falling. The gib 106 may be secured to the outer bearing seat by screws 107 or rivets, welding, or by any other suitable means.

The hook body 105 is an outer bearing. On the inner wall of the hook body 105 is a hub portion 108 where rolling elements, such as ball bearings 109 or rollers, can be placed, optionally held in by a riveted cage 110. The rolling elements allow the hook body 105 to rotate with respect to an inner bearing spindle 126 (acting as an inner bearing), as will be explained below.

The outer bearing hook body 105 has a second cylindrical portion having a cutout 111. The cutout 111 interrupts the cylindrical shape of the second cylindrical portion and forms a beak shape (a beak) 114 at one end of the cutout 111 and a forward end 115 at the opposite end of the cutout. The cutout 111 is configured for allowing the hook body 105 to receive a second thread tension case holder 112. One section of the inner wall of the outer bearing hook body 105 is cylindrical and includes a recessed raceway 113 at one end of the hook body’s inner wall. This recessed raceway 113 extends from the inner surface of the beak 114 to the inner surface of the forward end 115 of the cutout 111. The recessed raceway 113 is located at the edge of the hook body 105 and is capped at its edge by the flange 116 extending radially inwards from a retaining gib member 117 attached to the outer surface of the hook body 105. In this manner, when the retaining gib member is joined to the hook body 105, the recessed raceway 113 has a proximal wall formed inside the inner surface of the hook body and a distal wall formed by the flange 116. As will be explained later, the walled recessed raceway 113 can receive a rib 122 of the stationary second thread tension case holder 112 and enables the outer bearing hook body 105 to rotate or oscillate in a fixed path around the stationary second thread tension case holder 112. The retaining gib member 117 may be secured to the outer bearing hook body 105 by screws 107 or by any other suitable means.

Opposite the gib 117 and secured to the circumferential outer face of the outer bearing hook body 105 is a curved second thread guard 119 that matches the cylindrical shape of the outer wall of the hook body 105. The second thread guard 119 may be secured in place by screws 107 or rivets or by any other suitable means. The second thread guard 119 has two ends: a first end of the curved section is configured to be positioned adjacent to the region of the beak 114, and a second end opposite the first end along the curved section which has an extension 120 projecting along the curve. The width of the first end along the axis of the cylindrical hook body 105 tapers, so that a second beak shape 121 is formed on the first end of the second thread guard 119. The projection at the second end of the second thread guard 119 functions as a second thread catchment point 120.

As shown in Fig. 11, the first beak 114 and the second beak shape 121 taper in opposite directions, so that a void is formed between the edges of the first beak 114 and of the second beak 121. The void enables the passage of the downward moving needle 152 of the sewing machine to pass briefly within the void formed by the first beak 114 and the second beak shape 121 at the appropriate time in the cycle of revolution of the outer bearing hook body 105.

At the second end of the second thread guard 119, the second catchment point 120 is configured for catching the loop formed by the upper thread (not shown) as the sewing machine’s needle 152 withdraws upward from the void between the first beak 114 and the second beak 121, during the rotation or oscillation of the main hook body 105.

The second thread tension case holder 112 has a cylindrical section having a rib 122 which extends outwards radially from the outer surface of the second thread tension case holder 112 along a portion of a circumference of the cylindrical section. The rib 122 is interrupted in an interrupted region 123, to enable the second thread tension case holder 112 to be inserted into the outer bearing hook body 105. This interrupted region 123 is in a region adjacent the top of the second thread tension case holder 112 and adjacent to an extension 124 extending radially away from the outer surface of the second thread tension case holder 112. The extension 124 cooperates with a detaining finger (not shown) secured to the chassis of a sewing machine. The detaining finger prevents rotation of the second thread tension case holder 112, while the outer bearing hook body 105 rotates or oscillates. The rib 122 on the second thread tension case holder 112 cooperates with a recessed raceway 113 which extends through the circumference of the inner wall of the outer bearing hook body 105, thus linking the outer bearing hook body 105 to the second thread tension case holder 112, while enabling rotation of the outer bearing hook body 105 with respect to the second thread tension case holder 112. In some embodiments of the present invention, the second tension case holder 112 includes a second indentation 134 on a side of its inner wall. The indentation is configured for cooperating with a tension case, as will be explained further below, in relation to Figs. 27-31. Optionally, the second indentation 134 is at the edge of the second tension case holder that is farthest from the outer bearing hook body 105.

The outer bearing hook body 105 is configured to be driven by a gear mechanism of the main drive shaft of the sewing machine. The second gear 125 of the outer bearing hook body 105 is configured to cooperate with the gear-based driving mechanism of the sewing machine. In this manner, as the gear mechanism rotates or oscillates, the second gear 125 is rotated or oscillated as well, causing the outer bearing hook body 105 to rotate or oscillate. The teeth for the second gear 125 of the outer bearing hook body 105 may be located on an outer surface (Figs. 10, 11, 15, 20) or an inner surface of the outer bearing hook body 5 (Fig. 19), and may be on a fore end (Fig. 20) or an aft end (Figs. 10, 11, 15, 19) of the of the outer bearing hook body 105.

Within the hollow area of the outer bearing hook body 105, is placed a spindle 126, which is the inner bearing. The spindle has a main hub portion 127 for the positioning and retaining the aforementioned rolling elements. The rolling elements are configured to roll against the outer surface of the spindle 126 and the inner surface of the outer bearing hook body 105 in order to allow coaxial rotation of the outer bearing hook body 105 with respect to the inner bearing spindle 126.

The spindle 126 is hollow and is sealed at a fore thereof end by the placement of a second horizontal pin 128 with a locking groove 129. The hollow section of the spindle 126 is configured for being traversed by a thread 132. The second horizontal pin 128 is centrally placed for receiving a tension case (described further below with reference to Figs. 27-31). The locking groove 129 is circumferential recess around the end of the second horizontal pin 128. The locking groove 129 serves as a locking point to cooperate with the tension case and hold the tension case in a desired position.

At a point behind the locking groove 129 of the second horizontal pin 128, an exit hole 130 is formed to allow the thread 132 to slip smoothly from the hollow portion of the spindle 126 in preparation to cooperate with a thread tension case.

The spindle 126 can be fixed in place with respect to the chassis of the sewing machine 150 by way of a flat recess 131 which is cut out on the outer side of the rear of the spindle. In this manner, the spindle can be held in place via a holding unit 200 which is attached to the chassis of the sewing machine 150 and cooperates with the flat recess 131, to make sure the spindle 126 is kept at a constant orientation so that the thread exits the exit hole 30 in the spindle 126 at the correct angle. An example of the holding unit 200 is shown in Figs. 25 and 26. In such an example, the holding unit includes a gripper 202, a tightening screw 204, and a base 206. The base 206 is joined to the bottom of the sewing machine 50, for example via screws 208. The base is connected to the gripper 202, which is shaped to grip the spindle 26. The tightening screw 204 is configured for tightening the gripper 202 around the spindle, thereby clamping the spindle 126 and preventing the spindle 126 from rotating. Figs. 21-24 illustrate the system 100 joined to a sewing machine 150, in order to feed the sewing machine 150 a lower thread. The system 100 is located under the chassis of the sewing machine 150. The scope of the invention extends to a sewing machine having the system 100.

Tension Case Holder

Referring now, to Figs. 27-31, a thread tension case 300 (also referred to as a tension case) is described. In the first thread feeding system of Figs. 1-9, the tension case 300 is configured for being received by the first thread tension case holder 9 and locked onto the first horizontal pin 14. In the second thread feeding system 100 of Figs. 10-26, the tension case 300 is configured for being received by the second thread tension case holder 112 and locked onto second horizontal pin 128.

The thread tension case 300 includes a main body, a spring 400, a horizontal pin lock 500, and a finger latch 600. The main body has the shape of a hollow cylinder and includes a cylindrical wall 302whichhas a cap 304 at an end thereof. The cap includes two protrusions 306 and 308 located respectively at a bottom section and at a top section of the cap. The protrusions 306 and 308 extend longitudinally away from the cylindrical wall 302. The first protrusion 306 has a first channel extending sideways along the outer surface of the cap and configured for receiving and holding a spring 400 and for receiving a first side of slide 502 of a horizontal pin lock 500, as will be explained further below. The second protrusion 308 has a second channel extending sideways along the outer surface of the cap and configured for receiving a second side of the slide 502 of the horizontal pin lock 500, as will be explained further below. It should be noted that the first protrusion or the second protrusion may be configured for holding the spring 400 in their channels.

The cap 304 has a hole 310 in the middle. The hole 310 enables passage of the first horizontal pin 14 of Fig. 1 or the second horizontal pin 128 of Fig. 10 through the cap 304. On the side of the cap 304 that faces the internal hollow space of the cylindrical wall 302, an inner shaft 312 extends inwards around at least part of the circumference of the hole 310. The inner cylindrical shaft 312 is configured for sheathing the first horizontal pin 14 of Fig. 1 or the second horizontal pin 128 of Fig. 10, to ensure that the tension case 300 is stably joined to the first thread tension case holder 9 of Fig. 1 or the inner bearing spindle 126 of Fig. 10. In some embodiments of the present invention, a perforation is cut on the inner cylindrical shaft as so to leave an opening to cooperate with the lower thread exit hole 130 of the inner bearing spindle 126 of Fig. 10. The perforation may be hole or a cut-away along the length of the shaft.

The cylindrical surface of the main body has a gap 314, which allows the sewing machine’s needle and its accompanying upper lock stitch thread to enter the hollow space inside the thread tension case and interact with the lower thread.

Cut on a side of the cylindrical wall 302, there is a chamfer 318 configured for being traversed by the lower thread. The chamfer provides a path for the lower thread in preparation for its engagement behind a thread tension spring 320, in order to aid in the resistance required for the lower thread to form the lower locking stitch. The direction of this cut chamfer 318 moves in an angular incline across the body of the cylindrical wall 302 and turns sharply to terminate in termination point 322. The termination point 322iscovered on the outside of the cylindrical wall by the thread tension spring 320.

The thread tension spring 320 is a curved elongated sheet having a first end removably joined to the outer surface of the cylindrical wall 302, while the second end is free. The curvature of the thread tension spring 320 is set to match the curvature of the cylindrical wall 302. The thread tension spring 320 can be removed and cleaned/replaced from time, as lint can build up under between the thread tension spring 320 and the cylindrical wall 302 from the flare of low quality thread. In some embodiments of the present invention, the first end of the thread tension spring 320 is removably joined to the cylindrical wall by a screw 324 or rivet, or by any other suitable means. If a screw 324 is used for joining the thread tension spring 322 to the cylindrical wall, the cylindrical wall includes a first screw opening 326 configured for being traversed by the screw 324.

In some embodiments of the present invention, between the end of the thread tension spring 320 joined to the cylindrical wall 302 and the free end of the thread tension spring 320, a tension adjustment screw 328 joins the thread tension spring 320 to the cylindrical wall 302. The tension adjustment screw may be tightened to decrease the distance of the free end of the thread tension spring from the cylindrical wall and may be loosened to increase the distance of the free end of the thread tension spring from the cylindrical wall. The cylindrical wall 302 includes second screw opening 330 configured to be traversed by the tension adjustment screw 328.

According to some embodiments of the present invention, the free end of the thread tension spring 320 has an inwardly depressed transverse rib 332. The rib 332 A delivery slot 334 is cut on the cylindrical wall 302 to receive and cooperate with the transverse rib 332 to aid in the correct positioning of the lower thread being delivered at the correct angle. The thread tension spring 320 is needed to create resistance to prevent the lower thread from being delivered in copious amounts onto the top of the fabric - an occurrence called“nesting”. The thread tension spring 320 places the lower thread under resistance and allows the right amount of thread to be expelled by the movement and motion of the sewing machine.

The tension spring has to be calibrated and adjusted for each thread and thread weight so that the upper and lower threads create the lock stitch for the required finished result for of the fabric/materials being sewn or embroidered. Adjustments of the thread tension spring 320 are also needed when using nylon threads and shirring elastic and many more variations of products that may be used in the lower thread area of a sewing or embroidery machine.

With an empty tension case or bobbin case, the free edge of the thread tension spring 320 rests against the cylindrical wall 302, but when a thread is placed correctly in the tension case, the thread slips between the wall and the spring and a gap is formed between the free end of the thread tension spring 320 and the cylindrical wall 302. With each passing motion or the rotation/ oscillation of the hook for the upper thread, as the upper and lower threads twist together to create the locking stitch, the free end of the thread tension spring 320 moves away from the cylindrical wall 302 and then returns back to the cylindrical wall 302, like an open and closing motion. When using thick thread, the gap is wide and the rib 332 of Fig. 10 assists the thread tension spring in returning to intended position and reduces/stops any sideways motion that can and does cause the tension adjustment screw 328 to undo over extended periods of operation.

Between the first and second protrusions 306 and 308, the cap 304 is flat and has two lateral sides. In a first lateral side, the cap 304 has a first latch insertion hole 335 having an outer end facing the edge of the cap 304 and an inner end facing the center of the cap 304. The inner end of the first latch insertion hole 335 is wider than the rest of the first latch insertion hole 335. On the second lateral side, the cap as a neck insertion hole 336, which extends to the edge of the cap and along part of the cylindrical wall 302.

The horizontal pin lock 500 includes a slide 502 and a neck 504. The slide 502 is flat and extends along a plane, while the neck 504 extends from a lateral side of the slide 502, curving away from the plane of the slide 502. The slide 502 includes a spring jam extension506 extending along the plane of the slidefrom the bottom side of the slide 502. The slide 502has a locking hole 508 around the middle of the slide 502, and a second latch insertion hole 510 which is located at a side of the slide opposite to the side from which the neck 504 extends. The second latch insertion hole 510 is shaped to match the shape of the first latch insertion hole 335.

The slide 502 of horizontal pin lock 500 is configured for being inserted into the first and second channels, such that the horizontal pin lock 500 can be slid within the channels from side to side along the surface of the cap 304 within the channels. The channels limit the motion of the horizontal pin lock along a single axis. The spring jam extension 506 of the slide 502 contacts the spring 400 inside the first channel of the first protrusion 306. The spring 400 is inserted into a spring insertion slot 307, which forms the bottom of the first channel of the first protrusion 306. In this manner, as the horizontal pin lock moves inside the first and second channel toward one side, the spring jam extension 506 compresses the spring against the lateral end of the first channel. Therefore, the spring 4001imits the movement of the horizontal pin lock 500, by applying a force to the spring jam extension 506 when the spring jam extension 506 compresses the spring 400 inside the first protrusion 306.

The finger latch 600 includes a planar panel 602 and a curved extension 604 extending away from one side of the planar panel 602 and curving away from the plane of the planar panel 602. A head 606 is located at the edge of the curved extension 604 and as a top-to-bottom width larger than the maximal top-to-bottom width of the curved extension.

The spring 400 is inserted into the first channel of the first protrusion 306, so that a first end of the spring 400 contacts a side wall of the first channel. Then, the horizontal pin lock 500 is slid into the first and second channel so that the spring jam extension 506 contacts the second end of the spring 400. The first horizontal pin lock 500 is pushed until the first latch insert opening 335 on the cap and the latch insertion hole 510 on the horizontal pin lock are aligned. The head 604 of the finger patch 600 is inserted into the inner (wider) ends of the first latch insertion hole 335 and the second latch insertion hole 510. Then, the finger latch 600 is rotated so that the planar panel 602 lays flat on the slide 502. In doing so, the head 606 of the finger latch 600 is pushed radially outward into the outer (narrower) ends of the first latch insertion hole 335 and the second latch insertion hole 510. In this manner the head 606 cannot pass through the narrower ends of the first latch insert opening 335 and the latch insertion hole 510, and the finger latch 600 is joined to the cap 304 and the horizontal pin lock 500.

In working mode, the flat panel 602 of the finger latch 600 lays flat against the slide 502 of the horizontal pin lock 500. The first protrusion 306 together with the finger latch 600 and the second protrusion 308 form a convex surface, which assists in the casting and the smooth passing of the upper lock stitch thread as the upper lock stitch thread glides over the surface to catch the lower thread to form the locking stitch.

The neck 504 of the horizontal pin lock is extended to cooperate with the first indentation 31of the first thread tension case holder(see Fig. 1) or with the second indentation 134 of the second thread tension case holder (see Figs. 10 and 16) to prevent any rotation of the tension case. The horizontal pin lock 500 is held in the working position by the pressure of the spring 400 against the spring jam extension 506. As the finger latch 600 is opened by a user (the planar panel 602 is rotated away from the slide 502), the hinge formed by the curved extension 604 and the head 606 forces the horizontal pin lock 500 to slide sideways. In this manner, the locking hole 508 is aligned with the hole 310 on the cap 304, and enables insertion or removal of the first horizontal pin 14 of Fig. 1 or of the second horizontal pin 128 of Fig. 10 through the locking hole 508 of the horizontal pin lock and the hole 310 on the cap 304. At the same time, the sliding on the horizontal pin lock 500 causes the neck 500 to draw itself into the neck insertion hole 336, thereby releasing the thread tension case 300 from the first or second thread tension case holder, or allowing insertion of the thread tension case 300 into the first or second thread tension case holder.

After the thread tension case 300 is inserted into the first or second thread tension case holder (with the finger latch lifted up), the finger latch is rotated so that the planar panel 602 lies flat against the slide 502. This causes the horizontal pin lock to slide sideways so that the locking hole 508 of the horizontal pin lock closes around circumferential recess 14a of the first thread feeding system of Figs. 1-9, locking the tip of the first horizontal pin 14 on the outside of the tension case 300 and preventing a movement of the tension case 300 along the first horizontal pin. Similarly, the horizontal pin lock sliding sideways closes the locking hole 508 around locking grove 129 of the second thread feeding system of Figs. 10-26, locking the tip of the second horizontal pin 128 on the outside of the tension case 300 and preventing a movement of the tension case along the second horizontal pin 128.

In some embodiments of the present invention, situated on first protrusion306 is cut a window 338. This is to allow access to the lower lock stitch thread, so that any surplus thread maybe drawn away from the thread tension case before being pulled through the thread delivery slot. In some embodiments of the present invention, on the outer wall of the shaft 312 is a first locking point groove 340. On the inner wall of the cylindrical wall case body is a second locking point groove 342. These two locking point grooves hold in place a curved spring clip 344. The curvature of this spring clip 344 assists in the guiding of the thread as it passes from the exit point and slips across the curvature of the spring clip 344 before entering into the chamfer 318 of the thread tension case body. Optionally, the spring clip 344 is removable, so that calibration of the thread tension spring 320 for different threads can be executed. The calibration process is similar to the manual calibration process used with lower thread bobbins and bobbin cases. In the calibration process, a full bobbin is inserted into a bobbin case. The user/technician attaches a set of weights that correspond to the resistance required to the bobbin case. Then holding the thread from the bobbin, the bobbin case, the bobbin and weights are suspended in the air from the technician’s hand. The technician makes a series of jerking hand movements and gravity makes the bobbin case fall to the floor. The bobbin case is stopped from reaching the floor by the tension spring applying tension to the thread. The distance the bobbin case falls until the spring stops the motion is how the bobbin case is calibrated. A trained eye knows how far this motion/distance should be. Therefore, removing the spring clip is necessary for allowing a bobbin to be inserted into the thread tension case 300 and performing the calibration process.

Optionally, the window 338 allows access to check the spring clip 344 is performing its intended function of guiding the lower lock stitch thread toward the termination point 322 of the chamfer 318.

The invention is not to be understood as limited to the details of construction and relative arrangements and proportions of parts of the preferred embodiment thereof shown and described, as modifications thereof may obviously be made by those skilled in the art within the spirit and scope of the invention.

The invention is not to be understood as limited to the details of construction and relative arrangements and proportions of parts of the preferred embodiment thereof shown and described, as modifications thereof may obviously be made by those skilled in the art within the spirit and scope of the invention.