sewing machine

A machine for sewing, often having additional attachments for special stitching.

Background

Before 1900, women spent many of their daylight hours sewing clothes for themselves and their families by hand. Women also formed the majority of the labor force that sewed clothes in factories and wove fabrics in mills. The invention and proliferation of the sewing machine freed women of this chore, liberated workers from poorly paid long hours in factories, and produced a wide variety of less expensive clothing. The industrial sewing machine made a range of products possible and affordable. The home and portable sewing machines also introduced amateur seamstresses to the delights of sewing as a craft.

History

The pioneers in the development of the sewing machine were hard at work at the end of the eighteenth century in England, France, and the United States. The English cabinetmaker Thomas Saint garnered the first patent for a sewing machine in 1790. Leather and canvas could be stitched by this heavy machine, which used a notched needle and awl to create a chain stitch. Like many early machines, it copied the motions of hand sewing. In 1807, a critical innovation was patented by William and Edward Chapman in England. Their sewing machine used a needle with an eye in the point of the needle instead of at the top.

In France, Bartheleémy Thimmonier's machine patented in 1830 literally caused a riot. A French tailor, Thimmonier developed a machine that stitched fabric together by chain stitching with a curved needle. His factory produced uniforms for the French Army and had 80 machines at work by 1841. A mob of tailors displaced by the factory rioted, destroyed the machines, and nearly killed Thimmonier.

Across the Atlantic, Walter Hunt made a machine with an eye-pointed needle that created a locked stitch with a second thread from underneath. Hunt's machine, devised in 1834, was never patented. Elias Howe, credited as the inventor of the sewing machine, designed and patented his creation in 1846. Howe was employed at a machine shop in Boston and was trying to support his family. A friend helped him financially while he perfected his invention, which also produced a lock stitch by using an eye-pointed needle and a bobbin that carried the second thread. Howe tried to market his machine in England, but, while he was overseas, others copied his invention. When he returned in 1849, he was again backed financially while he sued the other companies for patent infringement. By 1854, he had won the suits, thus also establishing the sewing machine as a landmark device in the evolution of patent law.

Chief among Howe's competitors was Isaac M. Singer, an inventor, actor, and mechanic who modified a poor design developed by others and obtained his own patent in 1851. His design featured an overhanging arm that positioned the needle over a flat table so the cloth could be worked under the bar in any direction. So many patents for assorted features of sewing machines had been issued by the early 1850s that a "patent pool" was established by four manufacturers so the rights of the pooled patents could be purchased. Howe benefited from this by earning royalties on his patents; Singer, in partnership with Edward Clark, merged the best of the pooled inventions and became the largest producer of sewing machines in the world by 1860. Massive orders for Civil War uniforms created a huge demand for the machines in the 1860s, and the patent pool made Howe and Singer the first millionaire inventors in the world.

Improvements to the sewing machine continued into the 1850s. Allen B. Wilson, an American cabinetmaker, devised two significant features, the rotary hook shuttle and four-motion (up, down, back, and forward) feed of fabric through the machine. Singer modified his invention until his death in 1875 and obtained many other patents for improvements and new features. As Howe revolutionized the patent world, Singer made great strides in merchandising. Through installment purchase plans, credit, a repair service, and a trade-in policy, Singer introduced the sewing machine to many homes and established sales techniques that were adopted by salesmen from other industries.

The sewing machine changed the face of industry by creating the new field of ready-to-wear clothing. Improvements to the carpeting industry, bookbinding, the boot and shoe trade, hosiery manufacture, and upholstery and furniture making multiplied with the application of the industrial sewing machine. Industrial machines used the swing-needle or zigzag stitch before 1900, although it took many years for this stitch to be adapted to the home machine. Electric sewing machines were first introduced by Singer in 1889. Modern electronic devices use computer technology to create buttonholes, embroidery, overcast seams, blind stitching, and an array of decorative stitches.

Raw Materials

Industrial machine

Industrial sewing machines require cast iron for their frames and a variety of metals for their fittings. Steel, brass, and a number of alloys are needed to make specialized parts that are durable enough for long hours of use in factory conditions. Some manufacturers cast, machine, and tool their own metal parts; but vendors also supply these parts as well as pneumatic, electric, and electronic elements.

Home sewing machine

Unlike the industrial machine, the home sewing machine is prized for its versatility, flexibility, and portability. Lightweight housings are important, and most home machines have casings made of plastics and polymers that are light, easy to mold, easy to clean, and resistant to chipping and cracking. The frame of the home machine is made of injection-molded aluminum, again for weight considerations. Other metals, such as copper, chrome, and nickel are used to plate specific parts.

The home machine also requires an electric motor, a variety of precision-machined metal parts including feed gears, cam mechanisms, hooks, needles, and the needle bar, presser feet, and the main drive shaft. Bobbins can be made of metal or plastic but must be precisely shaped to feed the second thread properly. Circuit boards are also required specific to the main controls of the machine, the pattern and stitch selections, and a range of other features. Motors, machined metal parts, and circuit boards can be supplied by vendors or made by the manufacturers.

Design

Industrial machine

After the automobile, the sewing machine is the most precisely made machine in the world. Industrial sewing machines are larger and heavier than home machines and are designed to perform only one function. Manufacturers of clothing, for example, use a series of machines with distinct functions that, in succession, create a finished garment. Industrial machines also tend to apply chain or zigzag stitch rather than lock stitch, but machines may be fitted for up to nine threads for strength.

Makers of industrial machines may supply a single-function machine to several hundred garment plants all over the world. Consequently, field-testing in the customer's factory is an important element in design. To develop a new machine or make changes in a current model, customers are surveyed, the competition is evaluated, and the nature of the desired improvements (such as faster or quieter machines) are identified. Designs are drawn, and a prototype is made and tested in the customer's plant. If the prototype is satisfactory, the manufacturing engineering section takes over the design to coordinate tolerance of parts, identify parts to be manufactured in-house and the raw materials needed, locate parts to be provided by vendors, and purchase those components. Tools for manufacture, holding fixtures for the assembly line, safety devices for both the machine and the assembly line, and other elements of the manufacturing process must also be designed along with the machine itself.

When the design is complete and all parts are available, a first production run is scheduled. The first manufactured lot is carefully checked. Often, changes are identified, the design is returned to development, and the process is repeated until the product is satisfactory. A pilot lot of 10 or 20 machines is then released to a customer to use in production for three to six months. Such field tests prove the device under real conditions, after which larger scale manufacture can begin.

Home sewing machine

Design of the home machine begins in the home. Consumer focus groups learn from sewers the types of new features that are most desired. The research and development (R&D) department of a manufacturer works, in conjunction with the marketing department, to develop specifications for a new machine that is then designed as a prototype. Software for manufacturing the machine is developed, and working models are made and tested by users. Meanwhile, R&D engineers test the working models for durability and establish useful life criteria. In the sewing laboratory, stitch quality is precisely evaluated, and other performance tests are conducted under controlled conditions.

When the new machine is approved for production, product engineers develop manufacturing methods for the production of machine parts. They also identify the raw materials needed and the parts that are to be ordered from outside sources. Parts made in the factory are put into production as soon as the materials and plans are available.

The Manufacturing
Process

Industrial machine

• The basic part of the industrial machine is called the "bit" or frame and is the housing that characterizes the machine. The bit is made of cast iron on a computer numerical control (CNC) machine that creates the casting with the appropriate holes for inserting components. Manufacture of the bit requires steel castings, forging using bar steel, heat-treating, grinding, and polishing to finish the frame to the specifications needed to house the components.
• Motors are usually not supplied by the manufacturer but are added by a supplier. International differences in voltage and other mechanical and electrical standards make this approach more practical.
• Pneumatic or electronic components may be produced by the manufacturer or supplied by vendors. For industrial machines, these are typically made of metal rather than plastic parts. Electronic components are not necessary in most industrial machines because of their single, specialized functions.

Home sewing machine

Parts production in the factory may include a number of precisely made components of the sewing machine.

• Gears are made of injection-molded synthetics or may be specially tooled to suit the machine.
• Drive shafts made of metal are hardened, ground, and tested for accuracy; some parts are plated with metals and alloys for specific uses or to provide suitable surfaces.
• The presser feet are made for particular sewing applications and can be interchangeable on the machine. Appropriate grooves, bevels, and holes are machined into the feet for their application. The finished presser foot is hand polished and plated with nickel.
• The frame for the home sewing machine / is made of injection-molded aluminum. High-speed cutting tools equipped with ceramic, carbide, or diamond-edged blades are used to drill holes and to mill cuts and recesses to house features of the machine.
• Covers for the machines are manufactured from high-impact synthetics. They are also precision-molded to fit around and protect the machine's components. Small, single parts are preassembled into modules, whenever possible.
• The electronic circuit boards that control the machine's many operations are produced by high-speed robotics; they are then subjected to a burn-in period that is several hours long and are tested individually before being assembled in the machines.
• All of the parts that are preassembled I; join a main assembly line. Robots move the frames from operation to operation, and teams of assemblers fit the modules and components into the machine until it is complete. The assembly teams take pride in their product and are responsible for purchasing the components, assembling them, and making quality control checks until the machines are completed. As a final quality check, every machine is tested for safety and various sewing procedures.
• The home sewing machines are sent to packing where they are separately assembled by power control units that are foot-operated. A variety of accessories and instruction manuals are packed with the individual machines. The packaged products are shipped to local distribution centers.

Quality Control

The quality control department inspects all raw materials and all components furnished by suppliers when they arrive at the factory. These items are matched with plans and specifications. The parts are again checked along every step of manufacture by the makers, receivers, or persons who add the components along the assembly line. Independent quality control inspectors examine the product at various stages of assembly and when it is finished.

Byproducts/Waste

No byproducts result from sewing machine manufacture, although a number of specialized machines or models may be produced at one plant. Waste is also minimized. Steel, brass, and other metals are salvaged and melted down for precision castings whenever possible. Remaining metal waste is sold to a salvage dealer.

The Future

The merging of the capabilities of the electronic sewing machine and the software industry is creating an ever-widening range of creative features for this versatile machine. Efforts have been made to develop threadless machines that inject thermal fluids that harden with heat to finish seams, but these may fall outside the definition of "sewing." Large embroideries can be machine-produced based on designs developed onscreen using AUTOCAD or other design software. The software allows the designer to shrink, enlarge, rotate, mirror designs, and select colors and types of stitches that can then be embroidered on materials ranging from satin to leather to make products like baseball caps and jackets. The speed of the process lets products celebrating today's victories hit the street by tomorrow's business day. Because such features are add-ons, the home sewer can buy a basic home sewing machine and enhance it over the years with only those features most frequently used or of interest. Sewing machines become individual crafting devices and, therefore, seem to have a future as promising as the imagination of the operator.

Where to Learn More

Books

Finniston, Monty, ed. Oxford Illustrated Encyclopedia of Invention and Technology. Oxford University Press, 1992.

Travers, Bridget, ed. World of Invention. Gale Research, 1994.

Periodicals

Allen, 0. "The power of patents." American Heritage, September/October 1990, p. 46.

Foote, Timothy. "1846." Smithsonian, April. 1996, p. 38.

Schwarz, Frederic D. "1846." American Heritage, September 1996, p. 101

[Article by: Gillian S. Holmes]

A mechanism that stitches cloth, leather, book pages, and other material by means of a double-pointed needle or any eye-pointed needle. In ordinary two-threaded machines, a lock stitch is formed (see illustration). A presser foot held against the material with a yielding spring adjusts itself automatically to variations in thickness of material and allows the operator to turn the material as it feeds through the machine. A cluster of cams, any one of which can be selected to guide the needle arm, makes possible a variety of stitch patterns. See also Cam mechanism.

Components of a modern sewing machine. (Singer Co.)

For more information on sewing machine, visit Britannica.com.

After almost one hundred years of trials, failures, and partial successes in Europe, the sewing machine in its practical form evolved as a mid-nineteenth-century American invention. Elias Howe, Jr., usually credited as the inventor, was not the first person to patent an American sewing machine. John J. Greenough, Benjamin W. Bean, and several others patented ideas for sewing machines in the early 1840s, before Howe was granted the first patent for the two-thread, lockstitch sewing machine in 1846. Howe's machine was far from adaptable for commercial production, and he met with little success in America at the time. The machine stitched only straight seams for the length of the baster plate, which then had to be reset. Taking his machine to England, Howe was unable to adapt it to British manufacturing needs, and he finally sold the patent rights in that country to William Thomas, a corset manufacturer.

When Howe returned home, he found that several other inventors had entered the field. John Bachelder had patented a continuous-feed, vertical-needle machine in 1849; Isaac M. Singer had used earlier ideas with his heart-shaped cam to move the needle and received a patent in 1851; and A. B. Wilson patented the stationary rotary bobbin in 1852 and the four-motion feed in 1854. The principal technical problems had been solved, but no single manufacturer could make a practical machine without being sued for infringement of patent by another. In 1856, Orlando B. Potter, lawyer and president of the Grover and Baker Sewing Machine Company, suggested the idea of pooling the patents. This was accomplished, but each company maintained itself separately, and there was competition in the manufacturing and improving of the various machines. The four members of the "sewing-machine combination" were Elias Howe, Jr.; Wheeler and Wilson Manufacturing Company; I. M. Singer and Company; and Grover and Baker Sewing Machine Company. All four members had to agree on which companies would be licensed to build sewing machines, and a fee of fifteen per machine was charged. Howe received five dollars of this amount, a portion was held in reserve for possible litigation costs, and the money left was divided equally among the four parties. In 1860, the fee was dropped to seven and Howe's share to one dollar. In 1867 Howe's renewed patent expired, and only the three companies were left. The combination remained active until 1877, when all the major patents expired. Although the combination had been accused of retarding the development of the sewing machine, hundreds of thousands of good machines were produced in the 1850s and 1860s.

The sewing machines were used by manufacturers for shirts, dresses, aprons, cloaks, collars, and many other items. Details such as pleating and tucking could be produced by machine very quickly and were popularly added to many costumes. While the sewing machine revolutionized the ready-made garment industry, it produced mixed results for workers. It initially reduced the number of laborers required, and it attracted unskilled men into sectors of the garment industry formerly reserved for women. Already poorly paid, women who subcontracted piece work at home now bore the additional expense of purchasing or renting equipment, and unscrupulous subcontractors often deducted payments on machines from meager wages, causing women to default. Contractors would then repossess the machine and "sell" it to the next job applicant. Those who could not afford a machine sought work in large shops where their work habits and productivity could be tightly controlled. By 1900 tents, awnings, sails, books, umbrellas, mattresses, hose, trunks, shoes, and flags were all stitched by machine.

The sewing machine was the first widely advertised consumer product. Because of the high initial cost of the machine, the Singer company introduced the hire-purchase plan, and installment buying placed a sewing machine in almost every home. Competition for this ready market encouraged more and more manufacturers to enter the field. At the height of this competition in the 1870s, there were well over two hundred American sewing machine companies. But foreign competition began to invade the field in the twentieth century. The high cost of skilled labor in America made it difficult to compete. Nevertheless, ingenious sewing machines are still in production, including those that "sew" without thread, but most of the machines produced in the United States are highly specialized manufacturing machines.

Bibliography

Bissell, Don. The First Conglomerate: 145 Years of the Singer Sewing Machine Company. Brunswick, Maine: Audenreed Press, 1999.

Brandon, Ruth. Singer and the Sewing Machine: A Capitalist Romance. London: Barrie and Jenkins, 1977.

Brewer, Priscilla J. The Queen of Inventions. Pawtucket, R.I.: Slater Mill Historic Site, 1986.

Cooper, Grace R. The Sewing Machine: Its Invention and Development. Washington, D.C.: Smithsonian, 1976.

Godfrey, Frank P. An International History of the Sewing Machine. London: R. Hale, 1982.

Sewing machines can make an excellent variety of plain or patterned stitches. They include means for gripping, supporting, and conveying the fabric past the sewing needle to form the stitch pattern. Most home sewing machines, and some industrial machines, use a two thread stitch called the lockstitch. Most industrial machines use an overlock stitch produced by a machine sometimes referred to as a serger. Some older machines produce a chain stitch. The material easily glides in and out of the machine without the hassle of needles and unessesary tools used in hand sewing.

The fabric shifting mechanism may be a simple workguide or may be pattern-controlled (e.g., jacquard type). Some machines can create embroidery-type stitches. Some have a work holder frame. Some have a workfeeder that can move along a curved path, while others have a workfeeder with a work clamp.

History of the sewing machine

Needle plate, foot and transporter of a sewing machine

Singer sewing machine (detail 1)

Lock stitch & Singer

Chain stitch has one major drawback – it is very weak and the stitch can easily be pulled apart. A stitch more suited to machine production was needed, it was found in the lock stitch. A lock stitch is created by two separate threads interlocking through the two layers of fabric, resulting in a stitch that looks the same from both sides of the fabric. Although the credit for the lock stitch machine is generally given to Elias Howe, Walter Hunt developed it first over ten years before, in 1834. His machine used an eye-pointed needle (with the eye and the point on the same end) carrying the upper thread, and a shuttle carrying the lower thread. The curved needle moved through the fabric horizontally, leaving the loop as it withdrew. The shuttle passed through the loop, interlocking the thread. The feed let the machine down – requiring the machine to be stopped frequently to set up again. Hunt grew bored with his machine and sold it without bothering to patent it.

Elias Howe paterted his machine in 1845; using a similar method to Hunt's, except the fabric was held vertically. The major improvement he made was to put a groove in the needle running away from the point, starting from the eye. After a lengthy stint in England trying to attract interest in his machine he returned to America to find various people infringing his patent. He eventually won his case in 1854 and was awarded the right to claim royalties from the manufacturers using ideas covered by his patent. Isaac Merritt Singer has become synonymous with the sewing machine. Trained as an engineer, he saw a rotary sewing machine being repaired in a Boston shop. He thought it to be clumsy and promptly set out to design a better one. His machine used a flying shuttle instead of a rotary one; the needle was mounted vertically and included a presser foot to hold the cloth in place. It had a fixed arm to hold the needle and included a basic tensioning system.

This machine combined elements of Thimonnier’s, Hunt's, and Howe’s machines. He was granted an American patent in 1851 and it was suggested he patent the foot pedal (or treadle) used to power some of his machines; however, it had been in use for too long for a patent to be issued. When Howe learned of Singer’s machine he took him to court. Howe won and Singer was forced to pay a lump sum for all machines already produced. Singer then took out a license under Howe’s patent and paid him $15 per machine. Singer then entered a joint partnership with a lawyer named Edward Clark, and they formed the first hire-purchase (time payment) scheme to allow people to afford to buy their machines.

Meanwhile Allen Wilson had developed a reciprocating shuttle, which was an improvement over Singer’s and Howe’s. However, John Bradshaw had patented a similar device and was threatening to sue. Wilson decided to change track and try a new method. He went into partnership with Nathaniel Wheeler to produce a machine with a rotary hook instead of a shuttle. This was far quieter and smoother than the other methods, and the Wheeler and Wilson Company produced more machines in 1850s and 1860s than any other manufacturer. Wilson also invented the four-motion feed mechanism; this is still seen on every machine today. This had a forward, down, back, and up motion, which drew the cloth through in an even and smooth motion.

Through the 1850s more and more companies were being formed and were trying to sue each other. Charles Miller patented the first machine to stitch buttonholes (US10609). In 1856 the Sewing Machine Combination was formed, consisting of Singer, Howe, Wheeler and Wilson, and Grover and Baker. These four companies pooled their patents, meaning that all the other manufacturers had to obtain a license and pay $15 per machine. This lasted until 1877 when the last patent expired.

Overlock

A Merrow A-Class machine (2007)

A Merrow 70-Class machine(2007)

In 1822 J. Makens Merrow purchased a powder mill in Mansfield, Connecticut for the manufacture of gunpowder. The mill was destroyed shortly thereafter by a gunpowder explosion. J.M. Merrow then founded one of the first knitting mills in the United States in partnership with his son, Joseph B. Merrow, under the name J. M. Merrow and Son. This knitting mill was located on the site of the old gunpowder mill in Mansfield, CT.

In the 1840s a machine shop was established at the Merrow mill to develop specialized machinery for the knitting operations. In 1877 the world’s first crochet machine was invented and patented by Joseph M. Merrow, then-president of the company. This crochet machine was the first production overlock sewing machine. The Merrow Machine Company went on to become one of the largest American Manufacturers of overlock sewing machines, and continues to be a global presence in the 21st century as the last American overlock sewing machine manufacturer.

James Edward Allen Gibbs (1829-1902), a farmer from Raphine in Rockbridge County, Virginia patented the first chain-stitch single-thread sewing machine on June 2, 1857. In partnership with James Wilcox, Gibbs became a principal in Wilcox & Gibbs Sewing Machine Company. Wilcox & Gibbs commercial sewing machines are still used in the 21st century.

In 1905 Merrow won a lawsuit against Wilcox & Gibbs for the rights to the original crochet stitch

Sewing machines continued being made to roughly the same design, with more lavish decoration appearing until well into the 1900s when the first electric machines started to appear. At first these were standard machines with a motor strapped on the side. As more homes gained power, these became more popular and the motor was gradually introduced into the casing.

Modern machines may be computer controlled and use stepper motors or sequential cams to achieve very complex patterns. Most of these are now made in Asia and the market is becoming more specialized, as fewer families own a sewing machine.

Modern sewing machines

The usage of sewing machines has grown over the years and is generally now used far more than sewing by hand. The industrial market has come to be dominated by several large brands such as Juki, Brother Industries, Merrow, Durkopp Adler, Pfaff, Consew to name a few.

Stitch formation

Sewing machines can make a great variety of plain or patterned stitches. Ignoring strictly decorative aspects, over three dozen distinct stitch formations are formally recognized by the ISO 4915:1991 standard (for a summary see [1], [2], or [3]), involving one to seven separate threads to form the stitch. Plain stitches fall into four general categories: lockstitch, chainstitch, overlock, and coverstitch.

Lock stitch is the familiar stitch performed by most household sewing machines and most industrial "single needle" sewing machines from two threads, one passed through a needle and one coming from a bobbin or shuttle. Each thread stays on the same side of the material being sewn, interlacing with the other thread at each needle hole. Industrial lockstitch machines with two needles, each forming an independent lockstitch with their own bobbin, are also very common.

Chain stitch is less widely used than lockstitch, but it is preferred over lockstitch for applications like sealing bags of grain, garment seams likely to be altered, and as a "safety stitch" on serging machines. A chain stitch may be formed with either one or two distinct threads, one passed through a needle and the other, if used, manipulated by a looper, a device which moves back and forth but does not pass through the fabric. The needle thread is formed on both sides of the material being sewn, and on the bottom of the material either crosses through loops of itself (single thread) or loops of the second thread to prevent it from pulling back to the top of the material. Most household chainstitch machines are either very old, or toys intended for children. Industrial chainstitch machines are still heavily used in their application areas.

Lockstitch and chainstitch can be formed any distance from the edge of the material being sewn. Overlock can only be formed at the edge itself, where one or more threads pass over the edge. Varieties of overlock stitch can be formed with one to four threads, one or two needles, and one or two loopers. Overlock sewing machines are usually equipped with knives that trim or create the edge immediately in front of the stitch formation. Household and industrial overlock machines are commonly used for garment seams in knit or stretchy fabrics, for garment seams where a clean finish is not required, and for protecting edges against ravelling. Machines using two to four threads are most common, and frequently one machine can be configured for several varieties of overlock stitch. Overlock machines with five or more threads usually make both a chainstitch with one needle and one looper, and an overlock stitch with the remaining needles and loopers. This combination is known as a "safety stitch". Household overlock machines are widely used.

Coverstitch is formed by two or more needles and one or two loopers. Like lockstitch and chainstitch, coverstitch can be formed anywhere on the material being sewn. One looper manipulates a thread below the material being sewn, forming a bottom cover stitch against the needle threads. An additional looper above the material can form a top cover stitch simultaneously. The needle threads form parallel rows, while the looper threads cross back and forth all the needle rows. Coverstitch is so-called because the grid of crossing needle and looper threads covers raw seam edges, much as the overlock stitch does. It is widely used in garment construction, particularly for attaching trims and flat seaming where the raw edges can be finished in the same operation as forming the seam. Machines with three needles are most common, and can be configured to use any two or all three of the needles. Machines with six or more needles are often used for applications like fastening elastic waistbands to garments. Household coverstitch machines are fairly rare, but are becoming more readily available.

Feed mechanisms

Besides the basic motion of needles, loopers and bobbins, all but the most trivial of stitches also requires the material being sewn to move so that each cycle of needle motion involves a different part of the material. This motion is known as feed, and sewing machines have almost as many ways of feeding material as they do of forming stitches. For general categories, we have: drop feed, needle feed, walking foot, puller, and manual. Often, multiple types of feed are used on the same machine. Besides these general categories, there are also uncommon feed mechanisms used in specific applications like edge joining fur, making seams on caps, and blindstitching.

Drop feed involves a mechanism below the sewing surface of the machine. When the needle is withdrawn from the material being sewn, a set of "dogs" is pushed up through slots in the machine surface, then dragged horizontally past the needle. The dogs are serrated to grip the material, and a "presser foot" is used to keep the material in contact with the dogs. At the end of their horizontal motion, the dogs are lowered again and returned to their original position while the needle makes its next pass through the material. While the needle is in the material, there is no feed action. Almost all household machines and the majority of industrial machines use drop feed. Differential feed is a variation of drop feed with two independent sets of dogs, one before and one after the needle. By changing their relative motions, these sets of dogs can be used to stretch or compress the material in the vicinity of the needle. This is extremely useful when sewing stretchy material, and overlock machines (heavily used for such materials) frequently have differential feed.

Needle feed moves the material while the needle is in the material. In fact, the needle may be the primary feeding force. Some implementations of needle feed rock the axis of needle motion back and forth, while other implementations keep the axis vertical while moving it forward and back. In both cases, there is no feed action while the needle is out of the material. Needle feed is often used in conjunction with a modified drop feed, and is very commmon on industrial two needle machines. The advantage of needle feed over drop feed is that multiple layers of material, especially slippery material, can not slide with respect to one another, since the needle holds all layers together while the feed action takes place. Household machines do not use needle feed as a general rule.

A walking foot replaces the stationary presser foot with one that moves with the feed. A machine might have a single walking foot, or two walking feet with alternating action, and either drop feed or needle feed might be used as well. Walking foot feed is most often used for sewing heavy materials where needle feed is mechanically inadequate. It is also helpful with spongy or cushioned materials where lifting the foot out of contact with the material helps in the feeding action. Only a very few household machines have a walking foot, but this type of feed is common in industrial heavy duty machines.

Factory machines are sometimes set up with an auxiliary puller feed, which grips the material being sewn (usually from behind the needles) and pulls it with a force and reliability usually not possible with other types of feed. Puller feeds are seldom built directly into the basic sewing machine. Their action must be synchronized with the needle and feed action built into the machine to avoid damaging the machine. Pullers are also limited to straight seams, or very nearly so. Despite their additional cost and limitations, pulling feeds are very useful when making large heavy items like tents and vehicle covers.

Manual feed is used primarily in freehand embroidery, quilting, and shoe repair. With manual feed, the stitch length and direction is controlled entirely by the motion of the material being sewn. Frequently some form of hoop or stabilizing material is used with fabric to keep the material under proper tension and aid in moving it around. Most household machines can be set for manual feed by disengaging the drop feed dogs. Most industrial machines can not be used for manual feed without actually removing the feed dogs.

Finally, we turn to zig-zag and decorative stitches. Household machines perform only lockstitch, but almost all of them can do so in many different directions. By moving the needle from side to side, and changing the feed direction and distance, both fancy and utilitarian patterns can be sewn. The simplest example is zig-zag, where the needle moves to the left for one pass through the material, then to the right for the next pass. A household "blind stitch" takes several stitches in a straight line followed by one stitch to the right, then back to the original line. In older machines, the needle and feed motion is controlled by mechanical cams. Some household machines even offer a slot for user-replaceable custom stitch cams. In more recent designs, the needle and feed motion is controlled by electric motors. By adding controlled motion of the material being sewn through an additional set of motors, arbitrary customized patterns of 100cm or more in each direction can be sewn, opening the door to the very popular category of programmable household embroidery machines.

While even extremely basic household sewing machines have zig-zag and a small selection of other stitch patterns, industrial machines do not. Industrial zig-zag machines are available, but uncommon. There are essentially no fancy-pattern stitching industrial machines, other than dedicated embroidery and edge decoration machines. Most industrial machines sew only a straight line of stitches. Even something as simple as a bar-tack or a buttonhole stitch is usually done by a dedicated machine incapable of doing anything else. When a variety of decorative stitching is required rather than a single stitch, a "commercial" machine (basically a heavy duty household machine) is usually employed.

Mechanical configurations

In addition to stitch formation and feed, sewing machines can differ widely in mechanical configuration. The generally recognized configurations are: flat-bed, cylinder-bed, post-bed, and off-the-arm. With the exception of overlock, all basic stitch types and feed mechanisms are available in all these mechanical configurations. Some special applications have distinctive mechanical configurations. For example, industrial blindstitch machines are almost always configured with a cylinder bed and a swing-away auxiliary flat bed.

Most household and industrial sewing machines are flat-bed configurations where the material being sewn feeds across a simple horizontal surface. Flat-bed machines are frequently mounted in a table or cabinet whose top surface is flush with the machine bed, effectively extending the machine bed to an arbitrary size. The flat-bed configuration is excellent for general work. Its primarily limitation is making seams in material that can not be flattened out around the needle, usually due to existing seams or the rigidity of the material being sewn.

The household "free arm" machine is a variation on the industrial cylinder-bed configuration. The material being sewn feeds perpendicular to the axis of a horizontal column containing the feed dogs, bobbins and/or loopers. The fabric can pass freely under and around the column. The cylinder-bed configuration is widely used, and is ideal for operations like attaching cuffs or hems to material already sewn into cylinders. It is also popular for work on non-flat objects like shoes and saddles. The size and cross section of a cylinder-bed varies substantially. Some cylinders are actually cylindrical with a diameter as small as 5 centimeters, or 16 centimeters in circumference. Others, like the household "free arm" have a distinct flat top surface and may be as much as 50 centimeters in circumference.

In a post-bed configuration, the material being sewn feeds across the end of a vertical column containing the feed dogs, bobbins, and/or loopers. The fabric can drape freely downward in all directions. This configuration is never seen in household machines, and is less common in industrial machines than the cylinder-bed configuration. Post-bed machines are used for operations with difficult access to the work area like glove making, shoe repair and attaching trims to mostly-completed garments. A height of a post-bed is not adjustable, but different models range in height from 10 to 45 centimeters, with 18 centimeters being common.

The off-the-arm configuration uses the third remaining possibility for feed direction with respect to a column. The material being sewn feeds along the axis of a horizontal column containing the feed dogs, bobbins, and/or loopers. The length of the column places a limit on the length of the seam that can be sewn, so this is the least common of the four basic mechanical configurations. However, off-the-arm machines are unexcelled for sewing sleeve and shoulder seams or other lengthwise seams that form a tube or cylinder. Multiple needle machines are common in the off-the-arm configuration, set up for double lap seaming, taping or flat-seaming in a single operation. Rarely, a machine will be set up to feed in the opposite direction or up-the-arm.

See also

• Textile industry
• Home appliance
• Overlock
• Merrow Sewing Machine Company
• Bernina Sewing Machine
• Singer Sewing Machine
• Pfaff
• Husqvarna Viking

External links

• Sewing Machines, Historical Trade Literature Smithsonian Institution Libraries

Wikimedia Commons has media related to:

Sewing machine

• Old Sewing Machines and How They Work - with animations.
• [4] Singer/Veritas factory of Germany
• Animation of a bobbin in a sewing machine
• Pictures and detailed reviews of popular older mechanical sewing machines
• [5] Sewing Machine Blog
• [6] Online Sewing Machine Salespdc:Naehmaschien

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