Vacuum Cleaner

Background

The vacuum cleaner is the appliance that frightens the cat, is chased by the dog, and, perhaps, gives a home the most immediate appearance of being clean. Imagining a home without a vacuum cleaner is next to impossible; yet, like many time-and effort-saving devices, its widespread use is less than a century old.

History

There were no mechanical devices for cleaning rugs or carpeting until the 1840s. Before then, carpet cleaning was the duty of housemaids for the well-to-do and the women of the family for everyone else. Most rugs were made of rags that were woven together or braided in long ropes that were then stitched together as floor coverings. Carpets were woven of finer materials. Rugs and small carpets were taken outside several times a year, hung on heavy clothes-lines, and beaten with fan-shaped beaters to drive out the dust. Larger carpets were left in place and brushed; curtains were also cleaned by beating and brushing.

When carpets and rugs were cleaned, the furniture and many ornaments that characterized the fussy Victorian style had to be moved: a time-consuming and inefficient process. Even worse, the beaten-or brushed-out dust quickly resettled on the floors and furniture. This, of course, did nothing to sanitize the house.

Relief from this arduous task was still a long time coming. The vacuum cleaner had three significant ancestors, the first of which was the street-sweeping machine. Public streets collected much of the waste from private homes and were filthy. Joseph Whitworth, an enterprising English gentleman of the 1840s, mounted large coarse-bristled brushes onto a rotating drum inside a horse-drawn van. The turning brushes picked up street dirt and deposited it in the van. The home carpet sweeper was invented in 1858 by H. H. Herrick, but its complexity and inefficiency limited its success.

Carpet sweepers

Finally, in 1876, Melville Reuben Bissell, owner of a china shop in Grand Rapids, Michigan, made the first popular and successful carpet sweeper by putting rotary brushes in a small canister with a push handle. Bissell's invention was spurred by his own need: bits of packing-crate straw became imbedded in his carpet. The Bissell carpet sweeper picked up both straw and dust and contained them in the canister for later disposal. Bissell named his first model the "Grand Rapids" after his home town. It revolutionized home care by making the need for beating carpets less frequent.

On the other side of the Atlantic a British company called Ewbank dominated the market. By 1880, Ewbank sweepers were found in many homes including the palaces of Britain's royal family. Models came in several sizes; with Miniatures for ladies to operate, followed by the larger Standard and the Parlour Queen, which boasted "a very powerful pattern for the thickest piles." The carpet sweeper was dominant through the 1930s; its internal parts were cast of aluminum, making these machines light and easy to use.

Unfortunately, carpet sweepers lacked vacuum suction. They were effective to a certain point, but could not pull dust and dirt from deep within carpet pile. Inventor Hubert Cecil Booth saw a demonstration at the Empire Music Hall in London of an American machine that blew compressed air through carpeting; this produced a cloud of dust (proving how much was trapped inside the carpet), but the same dust only settled back into the carpet. The Americans had also experimented with suction devices since about 1859, but only a few factory cleaners reached the marketplace. Booth saw the future in suction. He proved this to friends in two startling demonstrations. In one, he placed a handkerchief on the carpet and sucked on the handkerchief with his mouth. The underside of the kerchief was filled with dirt. Even more startling, Booth was so eager to prove his thinking to friends that he knelt in front of a chair in a restaurant and sucked on the chair covering. Coughing and spluttering, he spat the extracted dirt into a hankie.

Vacuum cleaners

Booth gave the vacuum cleaner its start. His first vacuum cleaner, called "puffin Billy," was made of a piston pump. It did not contain any brushes; all the cleaning was done by suction through long tubes with nozzles on the ends. It was a large machine, mounted in a horse-drawn van that was pulled through the streets. The vans of the British Vacuum Cleaning Company (BVCC) were bright red; uniformed operators would haul hose off the van and route it through the windows of a building to reach all the rooms inside. Booth was harassed by complaints about the noise of his vacuum machines and was even fined for frightening horses. The BVCC's most prestigious engagement was cleaning the carpets in Westminster Abbey in London before the 1901 coronation of King Edward VII and Queen Alexandra.

The coronation cleaning led to a demonstration at Buckingham Palace, which had a system installed after the royal family saw the dirt Booth was able to suction out of the palace. Booth's vacuum system, however, was not suitable for individual homeowners. Some large buildings had Booth's machine installed in the basement with a network of tubes fitted into the walls of the rooms with sockets in the walls. Short lengths of tubing with nozzles were connected to the sockets, and this central cleaning system sucked the dust into a container in the basement. Booth rented his machines rather than sell them, but in the United States, David T. Kenney built similar equipment and sold it, mostly to office buildings like the Flick Building in New York.

Efforts to make smaller vacuum cleaners were slow to develop. Booth made a smaller version call the Trolley Vac in 1906, but it was very expensive and still weighed 100 lb (45 kg). Other cleaners included the Griffith (also debuting in 1906) and the Davies device, patented in 1909, which required a two-man operating crew—fine for wealthy households but not the average home.

In their drive to produce a single-operator vacuum cleaner, inventors experimented with many types of mechanical suction. Davies's machine had a rotating wheel that used four bellows to create suction. Other early vacuum cleaners used a wide range of suction devices, including rocking chairs to work the bellows, assorted hand pumps connected to nozzles, and reverse-action bicycle pumps. Davies produced a smaller machine in 1912 called the Wizard, and Kirby's patent of 1912 was a pushed machine that moved forward like a caterpillar to open a long suctioning container. K. von Meyenburg's invention consisted of a long hose and nozzle that was attached to a bellow device worn like a back pack.

James Murray Spangler, who, like Bissell, suffered from dust allergy and asthma, constructed an electric-powered vacuum cleaner in Canton, Ohio, in 1907. Spangler made a box of wood and tin with a broom handle to push it and a pillow case to hold the collected dust. Spangler's innovation was to connect the motor to a fan disc and a rotating brush, combining the best of Bissell's brush sweeper with the suction of a powered vacuum cleaner to pull more dust out of carpets.

Spangler himself did not have the money to promote the cleaner, but his relative, William H. "Boss" Hoover, a maker of leather goods, quickly saw the advantages of Spangler's machine. The first Model 0 Hoover vacuum was made in 1908 with a grey cheesecloth bag, cleaning tools, and a weight of only 40 lb (18 kg). Hoover found that the machines sold very well door-to-door because housekeepers could see the action on their own carpeting. Hoover quickly built a large retailing operation that spread to Britain by 1913; to this day, vacuum cleaning in England is called "hoovering," a measure of the impact the Spangler/Hoover machine had on everyday life.

Other machines by Eureka and Electrolux soon followed and even copied Hoover's door-to-door sales methods. Hoover added a beater rod to the cylinder in 1926, so the cleaner brushed, beat, and suctioned the carpet. In the 1930s, the Great Depression prevented many from buying such luxury goods; to make the vacuum a necessity, Hoover hired renowned industrial designer Henry Dreyfuss to reconfigure the vacuum cleaner. With a body made of Bakelite instead of tin, a lighter total weight, more efficient operation, a signal showing when the bag was full, and other innovations, the streamlined vacuum cleaner resembled a high-speed locomotive. A canister cleaner followed during World War II. Today, the vacuum cleaner is firmly established as a household essential.

Raw Materials

Most upright vacuum cleaner parts are manufactured as individual parts or subassemblies (groups of parts that fit together) by subcontractors using specifications established by the manufacturer. These are sent to the factory where they're inspected, then stored in bins that can be moved to the assembly line as needed. Companies usually do their own injection molding of large plastic parts, including the exterior housing, the connections that support the bag, handle parts, wheels, and the attachments provided with the vacuum cleaner. Some models that have removable plastic canisters to collect the dust that can be snapped off and emptied; these plastic cylinders are also injection molded in the factory using clear plastic pellets. Rubberized parts, like the hose that channels dust from the fan to the bag and the bumper around the edge of the housing, are also made in the factory. The dust bag is made of fabric and is sometimes lined; this help keep fine particles that escape from the replaceable paper bag from seeping out.

Design

Portable vacuum cleaners are made in many general configurations, providing a range of cleaning actions to meet a broad range of customer requirements. The canister type has a cylindrical body containing the motor, fan, and other operating parts, and a removable, disposable paper dust bag. The canister is pulled over the floor on a set of wheels. The upright model is a push-pull device also mounted on wheels; the motor is mounted in a housing over the fan, beater bar and brushes, and drive belt. An upright handle, extending vertically from the back of the machine, carries both the electrical power cord and brackets to hold the dust bag or plastic dust canister. A simple locking device on the rear of the motor unit allows the handle to be lowered so the operator can maneuver it under tables and around other furniture.

Vacuum cleaner design used to focus exclusively on cleaning effectiveness, ease of operation, and low noise level. Since about 1990, however, almost all major manufacturers have also produced lines to reduce dust and allergens during vacuuming. These units usually have removable plastic canisters to contain the dust and are less to let fine particles escape through the bags and back into the air. Many are also equipped with replaceable filters for very fine particles. The partial vacuum produced by the fan has been improved, with more powerful motors and fans that still operate quietly. Panasonic's models feature a bypass motor that pulls dirt directly into the bag preventing wobble of the fan and possible motor burnout. These models also have onboard attachments; the suction can be transferred directly to the attachments. Lighter materials and a lighter total weight for these units compensate for the weight of the attachments.

The Manufacturing Process

Plastic parts

• 1 Many of a vacuum cleaner's plastic parts begin with computerized drafting and design systems (CADD). The parts are shaped in a two-part steel mold, called a die that is lowered into the chamber of an injection-molding machine.
• 2 Tiny plastic pellets stored in a large hopper next to the machine are poured into a
  

  An example of a canister-type vacuum cleaner.
  heating vat and melted. The pellets are either purchased in the color desired or colored with pigments as they are melted.
• 3 The melted plastic, injected under high heat and pressure into the chamber of the injection molding machine, penetrates every part of the mold. The two halves of the mold open enough to let the plastic part fall into a bin. Although the pieces are still hot to the touch, the plastic hardens on contact with the air as the tool opens. The plastic pieces are stored in bins that can be rolled to the assembly line as needed.
• 4 Many identical plastic parts of the same type are made during the injection process. When the desired number have been made, the tool is removed from the injection molding machine, another one is inserted, and the process repeats as supplies of another part are formed.

The assembly line

• 5 Vacuum cleaners are manufactured in an assembly-line process, with workers at assembly stations attaching subassemblies or individual parts to the vacuum as it moves along the line. Assembling an upright vacuum starts with the base, which is made of metal or molded plastic. The steel beater bar with brushes fitted into (a subassembly) is then pulled from a bin and inserted into fitted notches at the front of the base. The beater bar has a locknut on one end and a cap on the other so the owner can open it and replace the brushes when necessary. A rubber drive belt is placed in a guide channel around the beater bar and pulled over a belt guide and motor pulley on the underside of the base.
• 6 A steel base plate is fitted into notches in the front of the base and latched into place with a cam lock (a turning lever) over the underside of the belt and pulley. The steel base plate is a subassembly that has small rollers on it and openings near its front where the beater bar and brushes will agitate the carpet (to release dirt) during operation.
• 7 At the rear of the base, an axle is inserted through a tunnel-like opening that passes from one side of the base to the other. A release handle is fitted onto one end of the axle; it is a simple locking lever that allows the vacuum's operator to lower the handle during operation or raise and lock it into place for storage. Wheels are added to both ends of the axle and are locked into place.
• 8 The fan is bolted onto the base, and the motor assembly is attached to the top side of the base. The electrical connections from the motor to the fan and light, and from the motor to the electrical cord connection are made. A lightbulb is installed in a socket in the front of the base. A plastic housing that forms the top of the vacuum cleaner and fully encloses the motor and fan is snapped into place. It has already had a rubberized bumper wrapped around its sides and front. It also carries a clear plastic panel allowing the light bulb inside to shine through as a "headlight."
• 9 Plastic fittings that support the bag and handle are attached to the rear of the base. An opening at the back of the base holds a rubberized length of flexible hose that transfers dust from the fan to the bag; this hose is fastened to the base opening and to the plastic fitting leading into the bag support. At the top end of the handle, a plastic unit that holds the top end of the bag is bolted through the handle. Next, electrical connections inside the handle are completed, and the electrical cord that has been attached to the back of the base is tied to the connections within the handle, allowing the machine's operation to be controlled by a switch near the top of the handle. The length of electrical cord leading from the machine to a power outlet is connected. For packing and shipping, this cord is looped and tied with a twist tie; the owner will wrap it around storage supports on the handle.
• 6 The final touches are added, including attaching the bag, the inner disposable bag, and outer markings (preprinted on decals that list the manufacturer, operating instructions, and information such as the serial number and the power of the motor).
• 10 The completed machine is taken to packing department where it is wrapped in a plastic bag and put in a carton. A box of plastic attachments, including nozzles and a hose for upholstery cleaning, is also put in the carton with an information booklet, assembly instructions, and a warranty card. The cartons, which have been preprinted with marketing information, are then closed, sealed, and stored for shipping and distribution.

Byproducts/Waste

The major manufacturers make different styles of vacuum cleaners, but they don't produce true byproducts. They produce or stock replacement parts and supplies (like disposable paper bags) for sale to both customers and retailers.

Imperfect injection-molded parts are remelted and mixed (in controlled quantities) into new batches of plastic. Paper items, such as the bags and shipping materials, are also made by outside suppliers and can be recycled.

Quality Control

Assembly-line workers can reject any imperfect parts or partially assembled machines they find. Supervisors also monitor assembly along the line and can reject parts and partial assemblies. They may periodically remove machines for inspection during the line manufacture. The motors are benchtested before installation. At the end of the assembly process, each machine is inspected for quality before it is sent to the packing department. Selected machines are also tested for operation before they are packed.

The Future

The vacuum cleaner is an essential part of every home no matter how small. It's typically one of the first small appliances purchased. Many families have several vacuum cleaners for dedicated uses. These specialized uses have helped broaden the lines of vacuums made. Designs have also changed as the importance of minimizing allergens like dust, dust mites, and pet hair has increased. Today's vacuum cleaners are more powerful, versatile, and convenient than their predecessors.