Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
  • B21F—WORKING OR PROCESSING OF METAL WIRE
  • B21F33/00—Tools or devices specially designed for handling or processing wire fabrics or the like
  • B21F33/04—Connecting ends of helical springs for mattresses
• • C—CHEMISTRY; METALLURGY
  • C21—METALLURGY OF IRON
  • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
  • C21D9/00—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor
  • C21D9/02—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor for springs

Definitions

• the present invention relates to a method and apparatus for manufacturing a strip or length of connected, pocketed coil springs and, more particularly, to a method and apparatus for manufacturing connected, pocketed coil springs which provide for fast, effective, efficient, and inexpensive product.
• the method and apparatus for making a strip of pocketed coil springs include machinery that coils wire supplied from a large spool, the coil spring is compressed into a space created by folded fabric and the combination is then enclosed using ultrasonic welding. Thereafter, the attitude of the compressed spring is altered and it is expanded within the fabric pocket whereby a line of joined or connected, individually encased, coil springs is created. Multiple strips may then be bonded together by adhesives to form, for example, the central portion of a mattress where upon the strips are encased with upholstery.
• Manipulating wire induces stress, particularly when the wire is first formed to the desired diameter and again when the wire is formed into coils.
• small diameter wire is formed from larger diameter wire by forcing the wire, while heated, through progressively smaller dies.
• a coil typically is formed by forcing "cold" wire against a die that bends the wire in a desired fashion.
• stress relief of the finished coil could be accomplished by batch heating the formed springs in an oven, or connecting each spring to an electrical source and passing a current through the wire. Neither of these processes are particularly effective or efficient. Batch heating results in springs with inconsistent characteristics in that those in one part of an oven may be heated differently from those in another part of the oven. With electric current heating, consistent and proper heating depends upon an operator's ability to consistently connect each spring in exactly the same way. In addition, use of electric current sometimes creates an undesirable electric arc which may mechanically degrade a spring.
• the present invention provides for a substantial improvement on the previous methods and apparatus for producing a strip of connected, pocketed coil springs.
• What is first described here is a method for making a length of connected, pocketed coil springs comprising the steps of providing a wire adapted to be formed into a plurality of coil spring, providing material for forming a plurality of spaces, each space to receive a coil spring, heating the wire to a temperature for relieving stress in the wire, forming the wire into a coil spring while the wire is at an elevated temperature, cooling the resulting coil wire spring to a temperature where intended deformation of the spring will be below the elastic limit of the wire, compressing the coil spring, manipulating the material to form the spaces, inserting the compressed coil springs into the spaces, and enclosing the material around each of the spaces to form a plurality of connected, spring filled pockets.
• An apparatus for forming a length of pocketed coil springs comprising in combination a wire supply apparatus for providing a wire to be coiled, a heating apparatus operatively connected to the wire supply apparatus for induction heating the wire as it passes from the supply apparatus to a coil forming apparatus, a coil forming apparatus operatively connected to the heating apparatus for bending the wire while the wire is at an elevated temperature, a severing apparatus operatively connected to the coil forming apparatus for separating coil wire springs from the wire supply apparatus, a cooling apparatus operatively connected to the coil forming apparatus for reducing the temperature of the coil wire springs, a material supply apparatus operatively connected to the coil forming apparatus for providing a length of material, a pocketing apparatus operatively connected to the material supply apparatus for receiving the length of material from the material supply apparatus and for receiving the coil wire springs from the cooling apparatus wherein each of the springs is inserted into a corresponding space formed by the length of material, an enclosing apparatus operatively connected to the
• An object of the present invention is to provide a method and apparatus which allow for stress relief of the metal wire that forms the coil springs of a length of connected, pocketed springs.
• Another aspect of the present invention is to provide a method and apparatus for making a strip of connected, pocketed coil springs that integrates heating of the wire from which coil springs are formed so as to relieve stress in the wire.
• a further aim of the present invention is to provide a method and apparatus for manufacturing a strip of connected, pocketed coil springs which are efficient thereby achieving a cost savings.
• Yet another advantage of the present invention is to provide a method and apparatus for cooling formed coil springs prior to their insertion in spaces formed in a length of material.
• Figure 1 is a flow diagram illustrating a method for making a strip of connected, pocketed coil springs.
• Figure 2 is a diagrammatic view of an apparatus for manufacturing a strip of connected, pocketed coil springs.
• the present invention relates to a method and an apparatus for making a line of connected, individually pocketed coil springs typically used in mattresses.
• the structure is commonly known as the Marshall construction.
• each spring is encased within its own fabric container or pocket.
• Pockets are generally formed between two plies of a strip of fabric, formed by one piece of fabric being folded upon itself and then fastened together longitudinally and transversely after compressed coil springs are inserted in the spaces between the plies.
• FIG. 1 there is shown a flow diagram illustrating the method of manufacturing a strip of connected, pocketed coil springs.
• the process begins with the provision of a spool of wire (10) and a spool of fabric material (12).
• the spool of material provides a fabric strip to a folding station (14) where the fabric is folded over on itself to form spaces for receiving compressed coil springs.
• the wire from the spool is heated (16) with the intention of relieving stress induced during the wire making process.
• the wire is then pushed against a tool (18) while at an elevated temperature which causes the wire to bend into a coiled shape. Because of the heating, the resulting wire is more ductile and there is a reduction in the coil forming stress.
• the wire is severed (20) freeing the coil spring from the wire strand emanating from the spool.
• the spring is then cooled (22) in a rotating carousel before the compressing step (24) which compresses the spring to a height of about 0.5 inches.
• a conveyor may be used.
• the wire spring is inserted (26) into a space provided in the folded fabric. Thereafter, the combined spring and fabric are passed to an enclosing station (28) where the fabric is formed into pockets by selectively attaching the two plies of the fabric using ultrasonic welding. The attachments occur both between each spring and along the longitudinal ends where the fabric strip folds come together or overlap. This forms an enclosure around each spring.
• the final step is orienting or turning (30) the spring in the pocket thereby allowing the spring to fully expand so as to create (32) the final length of connected, pocketed coil springs.
• the wire used for the springs is upholstery spring wire, SAE1065- SAE1075, and is one of three diameters: 0.071 inches, 0.083 inches or 0.094 inches.
• Tensile strength of the wire is approximately ASTM 230,000 to 305,000 p.s.i. It is, of course, understood that the tensile strength is a function of wire size and material.
• the wire is usually provided in feed rolls or supply reels (50) where the wire is wound around a tubular steel carrier in lengths of about 79,000 feet or 1800 pounds.
• the wire is pulled off the carrier by a set of powered rollers (51) operating at a speed to move the wire at approximately 320 feet per minute.
• Suitable wire may be purchased from Insteel Wire Products of Andrews, South Carolina.
• the wire then passes through a magnetic induction heating apparatus or station (52).
• the heating apparatus is a 25KW induction device which may be purchased from Inductoheat of Romeo, Michigan.
• the heating apparatus is formed in an insulative box, measuring about 43 inches long, 6 inches high and 6 inches wide. The heating apparatus will increase the temperature of the wire to between 450 °F and 500°F in approximate 0.63 seconds.
• the purpose of the heating apparatus is to heat- treat or stress-relieve the wire of those stresses induced during the wire manufacturing process and to provide a ductile material for coil forming, thereby reducing forming stresses.
• the heating process like the entire process, is conducted in a stop/go or on/off manner.
• the heater is activated only when the wire is moving. When there is a pause in the movement of the wire the heating apparatus is turned off. This insures consistent heating of each wire segment.
• the wire is heated in lengths of about 41 inches, and each spring is about 9 inches in length.
• the wire After the wire is heated it moves to a forming apparatus or station (54) where the wire is formed into a coiled shape while at an elevated temperature. This is done by forcing or pushing the wire against a tool.
• the tool is hardened steel and is shaped to bend the wire pushed against it in a continuous and predetermined manner. The result is a coil of about 2 5/8 inches in diameter.
• the wire is severed by a moveable cutting blade which shears the wire as it is forced against a stationary blade. It is to be noted that heating the wire before it is coiled allows for the "hot" forming of each spring.
• each coil spring is moved to a cooling apparatus or station (58) where each coil spring is positioned on a circular cooling carousel (59) which is mounted to rotate in a timed, indexed fashion.
• the carousel has a number of slots or openings, such as opening (61), for receiving springs. Each spring rests on the carousel as the carousel is rotated for a predetermined time.
• the amount of time each spring spends on the carousel is a function of the required temperature drop.
• the carousel is designed to support each spring for the predetermined time.
• the design of the carousel is a function of the manufacturing rate, the number of slots to be used and the position of the carousel slots when the springs are received and expelled by the carousel.
• the spring may be subjected to cooling air from a blower (57).
• the power of the blower whether the air should be refrigerated, the amount of air being moved, the temperature of the air and other such factors are a function of the predetermined cooled temperature to be reached, the velocity of the carousel, the starting temperature of the spring, the size of the opening or slot in the carousel and the diameter of the carousel, for example.
• the desired "cooled" temperature is approximately 150°F.
• the cooled spring is moved to a compressing apparatus or station (60) where an air operated piston descends and compresses each coil spring to about a half inch in preparation for its insertion into a pocket.
• the cooled spring temperature approximately 150°F, is a function of the metal used and should be below that temperature where a permanent deformation set will occur when the spring is compressed. Thereafter, the compressed spring is inserted into a fabric pocket; hence, the temperature must also be sufficiently low so as to not burn the fabric.
• a fabric material supply apparatus or station (62).
• a large spool of fabric material provides a length of fabric which is stretchable in a direction parallel to the direction of movement of the fabric.
• the fabric then proceeds to a folding apparatus or station (64) where the fabric is guided automatically to fold over onto itself to create a space which will later be occupied by the compressed springs.
• a pair of rollers (65) provide the drive for pulling the fabric from the supply station.
• the fabric then moves to a pocketing or inserting apparatus or station
• the loaded fabric moves next to an orienting or turning apparatus or station (70) where the pocketed springs, which will have partially expanded, are rotated by approximately 90° and allowed to expand fully to about 6 3/4 inches.
• the rotation and full expansion are accomplished by a series of rotating paddles which beat the pockets as the strip is pulled along by a chain drive (71).
• the final result is a completed length of connected, pocketed coil springs having the usual configuration of a connected row of fabric cylinders.
• Controlling the process and the manufacturing apparatus is a control apparatus (74) which functions to signal the appropriate stations when each is to perform an operation on the wire or on the fabric. In this fashion, the invention described above allows for a production rate of approximately 72 coil springs per minute.
• the control apparatus also provides for the stop/go, on/off or indexed movement of the entire process.
• the inventive method and apparatus provides for a number of advantages. First, stress imparted to a wire during the wire forming stage is reduced and the stress induced during coil forming is minimized. Second, minimizing such stress greatly improves the performance characteristics of the springs. Unwanted and undesirable deformation of the wire is dramatically reduced, and durability of the springs is enhanced.
• the present invention provides for a heat treating operation which conforms to an in-line manufacturing operation.
• the heating is rapid, non- contacting, and independent of the condition of the wire.
• the result is consistent springs from one to the next. Furthermore, no delay is introduced into the existing manufacturing operation.

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• Chemical & Material Sciences (AREA)
• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Materials Engineering (AREA)
• Thermal Sciences (AREA)
• Crystallography & Structural Chemistry (AREA)
• Physics & Mathematics (AREA)
• Metallurgy (AREA)
• Organic Chemistry (AREA)
• Wire Processing (AREA)
• Shaping Of Tube Ends By Bending Or Straightening (AREA)
• Casting Or Compression Moulding Of Plastics Or The Like (AREA)
• Springs (AREA)

Applications Claiming Priority (3)

Publications (1)

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• 1998
  • 1998-05-29 EP EP98926211A patent/EP1015151A1/de not_active Withdrawn
  • 1998-05-29 AU AU78104/98A patent/AU7810498A/en not_active Abandoned
  • 1998-05-29 JP JP11501035A patent/JP2000512914A/ja active Pending
  • 1998-05-29 HU HU0003166A patent/HUP0003166A3/hu unknown
  • 1998-05-29 BR BR9809886-1A patent/BR9809886A/pt not_active Application Discontinuation
  • 1998-05-29 CA CA002291822A patent/CA2291822A1/en not_active Abandoned
  • 1998-05-29 CN CN98807404A patent/CN1264327A/zh active Pending
  • 1998-05-29 IL IL13318698A patent/IL133186A0/xx unknown
  • 1998-05-29 WO PCT/US1998/011355 patent/WO1998053933A1/en not_active Ceased
  • 1998-05-29 PL PL98337209A patent/PL337209A1/xx unknown
  • 1998-05-29 SK SK1613-99A patent/SK161399A3/sk unknown
  • 1998-06-01 AR ARP980102549A patent/AR012893A1/es unknown
  • 1998-06-01 ZA ZA984692A patent/ZA984692B/xx unknown
  • 1998-06-01 CO CO98030700A patent/CO4870768A1/es unknown
  • 1998-06-01 PE PE1998000442A patent/PE43399A1/es not_active Application Discontinuation
  • 1998-06-16 TW TW087108577A patent/TW407074B/zh not_active IP Right Cessation

Non-Patent Citations (1)

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