MXPA99011008A - Method and apparatus for manufacturing coil springs - Google Patents

Abstract

A method and apparatus for forming a length of connected, pocketed coil springs to be used in mattresses and the like where wire (10) from a supply source is heated (16) to between 450 and 500 degrees Fahrenheit by an induction heater before the wire is coiled. Thereafter, the wire is hot coiled (18), severed (20) and cooled (22) below a temperature where a permanent set might occur fromfurther processing of the spring. Thereafter, the spring is compressed (24) in preparation for its insertion (26) into a space provided by stretchable fabric from a supply reel. The fabric (12) is folded (14) on itself to provide the space. The temperature of the spring must also be sufficiently low to contact the fabric without causing burns or other damage. After insertion of a compressed spring into the space, the fabric is ultrasonically welded (28) to create individual but connected pockets for each spring. Thereafter, the springs are oriented (30) to allow each spring to expand thereby creating the length of connected, pocketed coil springs.

Description

METHOD AND APPARATUS FOR MANUFACTURING HELICAL SPRINGS BACKGROUND OF THE INVENTION FIELD OF THE INVENTION The present invention relates to a method and apparatus for manufacturing a bundle or extension of packaged and connected coil springs and, more particularly, to a method and apparatus for manufacturing packaged and connected coil springs which provides a fast, efficient, and efficient product. cheap. 2. DESCRIPTION OF THE RELATED TECHNIQUE For many years methods and apparatus have been known to make a strip of individually packed and connected worm springs for mattresses and cushions. See, for example, a United States patent of 1901, 685,160 for Marshall. A description of a modern apparatus and method is found in a 1984 United States Patent No. 4,439,977 to Walter Strumpf. This patent in turn refers to previous United States patents since 1929 and 1931. Other patents of the United States have been granted that describe various aspects of apparatus REF .: 32204 and methods for making packaged and connected coil springs. For example, see United States Patent No. 4,234,983; No. 4,565,046; No. 4,566,926; No. 4,578,834; and No. 4,854,023, all for Strumpf; and No. 5,186,435 to Smith; No. 5,444,905 for St. Clair; No. 5,471,725 for Thrasher; and No. 5,509,887 for Smith. The descriptions of all the patents mentioned above are incorporated herein by reference. Briefly, the method and apparatus for making a strip of packaged coil springs include machinery that winds the supplied wire from a large spool, the coil spring is compressed in a space created by bent fabric and the combination is then closed using ultrasonic welding. Subsequently, the position of the compressed spring is altered and expanded within the fabric package so that a line of helical springs embedded individually and connected is generated. Then multiple strips can be joined together by adhesives to form, for example, the central portion of a mattress where the strips are encased with upholstery. There have been efforts over the years to improve the methods and apparatus for making packaged coil springs, as exemplified by the patents mentioned above. These efforts seek to improve the product, gain efficiency or reduce costs, and increase the reliability of various combinations of these objectives. An area of tension is the wire used for coil springs. As can be expected, the manipulation of the wire induces stresses, particularly when the wire is first formed to the desired diameter and again when the wire is formed into coils. Typically, a small diameter wire is formed from a larger diameter wire by forcing the wire, while hot, through progressively smaller dies. A spring is typically formed by forcing the wire "cold" against a die that bends the wire in a desired manner. If desired, tension release of the finished winding can be produced by heating the springs formed in an oven, or by connecting each spring to an electrical source and passing a current through the wire. None of these processes is particularly effective or efficient. The batch heating results in springs with inconsistent characteristics considering that one part of the furnace can be heated differently from another part of the furnace. With electric current heating, consistent and proper heating depends on the ability of the operator to consistently connect each spring in exactly the same way. In addition, the use of electric current sometimes generates an undesirable electric arc which can mechanically degrade a spring or spring.

It is evident that a better product will be obtained if an effective means of treating the spring wire can be found by heating, taking care of the manufacturing process constraints and the costs.

BRIEF DESCRIPTION OF THE INVENTION The present invention provides a substantial improvement over prior methods and apparatus for producing a strip of packaged and connected coil springs. What is described first herein is a method for manufacturing an extension of packaged and connected coil springs comprising the steps of providing a wire adapted to be formed into a plurality of coil springs, providing material for forming a plurality of spaces, each space is to receive a coil spring, heat the wire to a temperature to release the tension in the wire, shape the wire in a coil spring while the wire is at an "elevated temperature, cool the coiled wire coil spring to a temperature where The designed deformation of the spring will be less than the elastic limit of the wire, compress the coil spring, manipulate the material to form the spaces, insert the compressed coil springs into the spaces and close the material around each of the spaces to form a plurality of connected packages, filled with springs. an apparatus for forming an extension of packaged coil springs is described, the apparatus comprises in combination a wire supply apparatus for providing a wire to be wound, a heating apparatus operatively connected to the wire supply apparatus for heating induction of the wire as it passes from the supply apparatus to the winding forming apparatus, a winding forming apparatus operatively connected to the heating apparatus for bending the wire while the wire is at an elevated temperature, a cutting apparatus operatively connected to the wire forming apparatus for separating the wire helical springs from the wire supply apparatus, a furling apparatus operatively connected to the winding forming apparatus to reduce the temperature of the wire helical springs, a material supply apparatus operatively connected to the wire forming apparatus For providing a length of material, a packer apparatus operatively connected to the material supply apparatus for receiving the extension of material from the material supply apparatus and for receiving the wire coil springs of the cooling apparatus wherein each of the springs it is inserted into a corresponding space formed by the extension of material, a closing apparatus operatively connected to the packaging apparatus to define the spaces in the material extension whereby a connected length of packages is completed, and a control means connected operatively to the cooler apparatus and to the heating apparatus to control the conformation of the packaged coil springs. An object of the present invention is to provide a method and apparatus which allows the release of metallic wire tension which forms the coil springs of an extension of packaged and connected springs. Another aspect of the present invention is to provide a method and apparatus for making a strip of packaged and connected coil springs integrating the heating of the wire from which the coil springs are formed so as to release the tension in the wire. A further objective of the present invention is to provide a method and apparatus for manufacturing a strip of packaged and connected coil springs which are efficient so that cost savings are obtained. A further advantage of the present invention is to provide a method and apparatus for cooling conforming coil springs, prior to their insertion into the spaces that are formed in an extension of material. A more complete understanding of the present invention and other of its objects, aspects, goals and advantages thereof will be obtained from a consideration of the following description of the preferred embodiment when read together with the accompanying drawings that are provided with the same BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a flow diagram illustrating a method for manufacturing a strip of packaged and connected coil springs Figure 2 is a diagrammatic view of an apparatus for making a strip of packaged and connected coil springs.

DETAILED DESCRIPTION OF THE PREFERRED MODALITY Although the present invention is open to various modifications and alternative constructions, the preferred embodiments will be described herewith as shown in the drawings. However, it should be understood that there is no interest in limiting the invention to the particular forms described. On the contrary, the intention is to cover all the modifications, equivalents and alternatives that are within the spirit and scope of the invention as expressed in the appended claims.

The present invention relates to a method and apparatus for making a line of individually connected packaged coil springs, typically used in mattresses. The structure is commonly known as a Marshall construction. In this construction, each spring is enclosed within its own container or package of cloth. The. Packs are generally formed of two plies of a strip of cloth, formed by a piece of cloth that is folded over itself and which is then held together longitudinally and transversely after the compressed coil springs are inserted in the spaces between them. layers. Referring now to Figure 1, there is shown a flow chart illustrating the method of manufacturing a strip of packaged and connected coil springs. Generally, the process begins with the provision of a spool of wire (10) and a spool of material (12) of cloth. The reel of material provides a strip of fabric to a bending station (14) wherein the fabric is folded over itself to form the spaces for receiving the compressed coil springs. The spool wire is heated (16) with the intention of releasing the voltage induced during the wire manufacturing process. The wire is then pushed against a tool (18) while at an elevated temperature, which causes the wire to bend to a rolled shape. Due to the heating, the resulting wire is more ductile and there is a reduction in the forming tension of the winding. After shaping, the short wire (20) releases the helical spring from the wire chain that emerges from the spool. The spring is then cooled (22) on a rotating carousel prior to the compression step (24) which compresses the spring to a height of approximately 13 method (0.5 inches). It should be understood that other mechanisms may also be used to cool the springs in addition to the rotating carousel. For example, a transporter can be used. After compression, the wire spring is inserted (26) into a space provided in the folded fabric. Subsequently, the combined dock and fabric are passed to a closure station (28) wherein the fabric is formed into packages by selectively joining the two layers of the fabric using ultrasonic welding. ~ The joints occur both between each spring and along the longitudinal ends where the strip of fabric bends and joins to overlap. This forms an enclosure around each pier. The final stage is oriented to flip (30) the spring in the package by allowing the spring to expand completely so that it generates (32) the final length of the packaged and connected coil springs.

Now with reference to Figure 2, the method of the invention and the apparatus of the invention for making an extension of packaged and connected coil springs are shown in greater detail. The method and apparatus are considered simple and effective in terms of costs. The manufacturing process is also efficient and reliable, and results in a superior product. The wire used for the springs is wire for upholstery springs, SAE1065, SAE1075 and found in one of three diameters: 1.8 method (0.071 inches), 2.1 method (0.083 inches) or 2.4 method (0.094 inches). The tensile strength of the wire is approximately ASTM from 16,170 to 21,444 kg / cm2 (230,000 to 305,000 p.s.i). Of course, it is understood that the tensile strength is a function of the size of the wire and the material. The wire is usually provided in feed rollers or supply spools (50) wherein the wire is wrapped around a tubular steel carrier of lengths of approximately 24,000 m (79,000 feet) or 816 kg (1800 pounds). The wire is pulled from the carrier by a set of impeller rollers (51) operating at a speed to move the wire at approximately 97.5 m / min (320 feet per minute). The proper wire can be purchased from Andrews, South Carolina. The wire then passes through a magnetic induction heating apparatus or station (52). The heating apparatus is a 25 kw induction device which can be purchased from Inductoheat of Romeo, Michigan. The heating apparatus is constituted in an insulating box, measuring approximately 109 cm (43 inches) long, 15 cm (6 inches) high and 15 cm (6 inches) wide. The heating apparatus will increase the temperature of the wire between 232 ° C and 260 ° C (450-500 ° F) by approximately 0.63 seconds.The purpose of the heating apparatus is to heat treat or release the tension ~ of the wire from those induced voltages during The process of manufacturing the wire and providing a ductile material for the formation of the winding, so that the forming tensions are reduced.The heating process, like the whole process, is carried out in a manner High / forward or on / off The heater is activated only when a wire is moved When there is a pause in the movement of the wire, the heater shuts off.This ensures a heating consists of each wire segment. it is heated to approximately 104 cm (41 inches) in length, and each spring is approximately 23 cm (9 inches) in length.It should be noted that other heating processes have been attempted for Marshall construction, but without success. It has been found that these are expensive, slow and inconsistent. For example, in a batch oven heating, some springs will be exposed to different temperatures compared to other springs. In another process, called electric resistance heating, the electrodes are clamped to a fully formed spring and generate heat by passing an electrical current through the spring. The quality of this technique depends on the consistent mechanical contact between the clamping electrodes and the spring, a difficult task to carry out in a high-speed production process. Frequently, this method also produces hot spots, spots and the like. Heating the kiln in batches requires large parts and equipment, is clogging and requires additional handling. The creation of stains by heating by electrical resistance is especially harmful when the process that follows is the packaging in cloth, in the manufacturing process. After the wire is heated, it is moved to a forming apparatus or station (54), wherein the wire is formed into a rolled shape while at an elevated temperature. This is done by pushing or pushing the wire against a tool. The tool is made of hardened steel and is shaped to bend the wire pushed against it in a continuous and predetermined manner. The result is a roll of approximately 6.7 cm (2 5/8 inches) in diameter. After the coil spring is formed, the wire is cut by a movable cutting blade which cuts the wire as it is urged against a stationary blade. It should be noted that heating the wire before it is wound allows the "hot" formation of each spring. It is considered that the heating of the wire before the forming step of the winding releases induced stresses during the wire processing operation, when the wire is reduced in diameter, and the heating step will allow the spring forming step with less induced voltage to be carried out because the wire has been "worked" at an elevated temperature when it is in a more ductile state. After heating, shaping and cutting, the spring is moved to a cooling apparatus or station (58) wherein the coil spring is placed on a circular cooling carousel (59), which is mounted to rotate in a manner to provide and synchronized The carousel has several slots or openings, such as the opening (61) for receiving springs. Each spring rests on the carousel as the carousel rotates for a predetermined time. The amount of time each spring uses in the carousel is a function of the necessary temperature decrease. The carousel is designed to hold each spring for a predetermined time. The carousel design is a function of the manufacturing speed, the number of slots to be used and the position of the carousel slots when the springs are received and ejected by the carousel. During the time that the spring is transported by the carousel, or during a portion of this time, the spring "can be subjected to cooling air from a fan (57)." Fan power, as long as the air must to be cooled, the amount of air that moves, the air temperature and other similar factors, are a function of the predetermined cooling temperature to be achieved, the carrousel speed, the spring start temperature, the size of the the opening in the groove in the carousel and the diameter of the carousel, for example. Other factors may also be important. For the materials mentioned above, the desired "cooled" temperature is approximately 66 ° C (150 ° F). Subsequently, the cooled spring is moved to a compression apparatus or station (60) wherein an air operated piston descends and compresses each coil spring to approximately 1.3 cm (inch) in its preparation for insertion into a package. The cooled spring temperature, approximately 66 ° C (150 ° F), is a function of the metal used and must be less than the "temperature at which an establishment of a permanent deformation will occur when the spring is compressed. Compressed spring is inserted inside the fabric package; therefore, the temperature should also be low enough so that it does not burn the fabric. In addition to the wire supply apparatus, there is an apparatus or station (62) for supplying cloth material. A large spool of fabric material provides a fabric extension which is stretchable in a direction parallel to the direction of movement of the fabric. The fabric then advances to a folding apparatus or station (64), where the fabric is automatically guided to fold over itself to generate a space which will later be occupied by the compressed springs. A pair of rollers (65) provide the drive to push the fabric from the supply station. The fabric then moves to an apparatus or station (66) of packed or inserted where intercepts the movement of the coil springs now cooled and compressed.

Here, the cover plate keeps the springs compressed while a pushing mechanism slides each compressed spring into a space formed by the folded fabric. Then, the fabric containing the compressed springs is moved to a closing apparatus or station (68). Here, an ultrasonic welding mechanism descends and completes the construction of an enclosed package by selectively connecting together the fabric of two bent parts, both in a direction parallel to the line of displacement of the fabric, as well as in a line perpendicular to the direction of movement of the fabric. This separates a dock from your neighbor, online. Another set of drive rollers (69) pulls the fabric containing the springs of the closing station. The loaded web is subsequently moved to an orientation or flipped-over apparatus or station 70, where the packaged "" springs, which have been "" partially expanded, are rotated approximately 90 ° and allowed to fully expand. up to approximately 17.1 cm (6 3/4 inches). Complete rotation and expansion is carried out by a series of rotating paddles which strike the bags as the strip is pulled along by "a chain drive (71) .The end result is a full extension of packaged coil springs and connected to the usual configuration of a connected row of cloth cylinders For the control of the process and the manufacturing apparatus, there is a control apparatus (74) which functions to signal -the appropriate stations when each one is going to perform a operation on the wire or on the fabric In this way, the invention described above allows a production speed of approximately 72 coil springs per minute.The control apparatus also provides the feature of high / advance, on / off or proportional movement of the entire process The method and apparatus of the invention provides numerous advantages: Firstly, the tension imparted to the wire uring the wire forming step it is reduced, and the tension induced during the shaping of the winding is minimized. Secondly, the minimization of such tension greatly improves the performance characteristics of the springs. The unwanted or undesirable deformation of the wire is remarkably reduced, and the durability of the springs is improved. Third, when the undesirable deformation of a spring is reduced or eliminated, less wire is required to produce a durable helical spring. There is a saving in terms of material costs in a range of approximately 10-25%. The tension release process can also allow the use of wires with lower tensile strength, which generates more cost savings. Finally, the present invention provides a heat treatment operation which is adapted to an on-line manufacturing operation. The heating is fast, without contact and independent of the condition of the wire. The result is springs that are consistent with each other. In addition, no delays are introduced in the existing manufacturing operation.

The present specification describes in detail two embodiments of the invention. Other modifications and variations will be found, under the doctrine of equivalents, within the scope of the following claims. For example, changes in the various stations or devices are considered equivalent. Changes in temperature are also considered equivalent because the wire material also changes. Obviously, new technology or other variations will also be equivalent, because in no way is intended to limit in any way the request of the doctrine of equivalents. It is noted that in relation to this date, the best method known by the applicant to carry out the aforementioned invention, is the conventional one for the manufacture of the objects or products to which it refers.

Claims (20)

RE V ND CATIONS Having described the invention as above, the content of the following claims is claimed as property:

1. A method for manufacturing an extension of packaged and connected coil springs, characterized in that it comprises the steps of: providing a wire adapted to be formed in a plurality of coil springs, the wire has an elastic limit; providing fabric to form a plurality of spaces, each space is for receiving a coil spring, passing wire through a magnetic induction heating apparatus and heating the wire by means of magnetic induction heating to a temperature sufficient to release the tension in the wire, forming the wire in a coiled form while the wire is at an elevated temperature, cooling the coil wire spring resulting to a temperature where the proposed deformation of the spring is below the elastic limit of the wire; the coil spring; manipulate the fabric to form spaces for the coil springs; insert a compressed coil spring into each of the spaces; and "closing the material around each of the spaces to form a plurality of receptacles filled with a spring and connected.

2. The method according to claim 1, characterized in that: the heating step includes increasing the temperature of the wire to a range of about 232-260 ° C (450-500 ° F).

3. The method in accordance with the claim 1, characterized in that it includes the step of: providing a tool to cause the wire to bend.

4. The method according to claim 2, characterized in that: the wire providing step provides wire of wire diameter sizes of between 1.8 mm, 2.1 mm and 2.4 mm (0.071, 0.083 and 0.094 inches).

5. The method according to claim 2, characterized in that: the cooling step includes cooling the wire after shaping to approximately 66 ° C (150 ° F).

6. The method according to claim 4, characterized in that it includes the step of: producing packaged springs connected at a speed of about 72 per minute.

7. The method according to claim 6, characterized in that: wire is provided at a flow rate of approximately 97.5 m / min (320 feet per minute).

8. The method according to claim 1, characterized in that it includes: cutting the wire after the step of forming the coil spring; compressing the wire after the step of forming the coil spring; and orient the springs after the closing stage.

9. An apparatus for. forming an extension of packaged coil springs, characterized in that it comprises, in combination: a wire supply apparatus for providing a wire to be wound; a magnetic induction heating apparatus operatively connected to the wire supply apparatus for magnetic induction heating of the wire as the wire passes from the supply apparatus through the magnetic induction heating apparatus to a winding forming apparatus; the winding forming apparatus is operatively connected to the magnetic induction heating apparatus for bending the wire while the wire is at an elevated temperature; a cutting apparatus operatively connected to the winding forming apparatus for separating wound wire springs from the wire supply apparatus; a cooling apparatus operatively connected to the winding forming apparatus to reduce the temperature of the wire coil springs; a cloth supply apparatus operatively connected to the winding forming apparatus to provide a fabric extension; a packer apparatus operatively connected to the fabric supply apparatus for receiving the fabric extension from the fabric supply apparatus and for receiving the coiled wire springs of cooling apparatus wherein the springs are inserted within a corresponding space formed for the length of cloth; a closing apparatus operatively connected to the packaging apparatus to define spaces in the fabric extension whereby a connected extension of packages is completed; and a control means operatively connected to the cooling apparatus, and to the magnetic induction heating apparatus for controlling the conformation of the packaged coil springs.

10. The apparatus according to claim 9, characterized in that it comprises: a compression apparatus operatively connected to the cooling apparatus to receive the coil springs of the apparatus and to compress the springs or springs. before the springs are inserted into the spaces formed in the fabric; a bender apparatus operatively connected to the fabric supply apparatus for receiving the fabric from the fabric supply apparatus and for forming the spaces for receiving the helical springs; and an orienting apparatus operatively connected to the closure apparatus for rotating the springs in the spaces formed by the fabric.

11. The apparatus according to claim 10, characterized in that: the heating apparatus increases the temperature of the wire in a range from about 232 ° C to 260 ° C (450-500 ° F).

12. The apparatus according to claim 11, characterized in that: ~~~~ the cooling device reduces the temperature of the springs at an elevated temperature to approximately 66 ° C (150 ° F).

13. The apparatus according to claim 12, characterized in that: a control means is provided for the production of approximately 72 packaged and connected springs, per minute.

14. The apparatus according to claim 13, characterized in that: the wire supply apparatus supplies wire at approximately 97.5 m / min (320 feet per minute).

15. The apparatus according to claim 9, characterized in that: the cooling device is a rotating carrousel which receives springs of the winding forming apparatus.

16. The apparatus according to claim 9, characterized in that: the cooling device causes the wire coil springs to reach a temperature where the designed deformation of the spring will be less than the elastic limit of the wire.

17. The apparatus according to claim 10, characterized in that: the cooling device causes the wire coil springs to reach a temperature where the compression of the springs will be a deformation smaller than the elastic limit of the wire.

18. The apparatus according to claim 15, characterized in that: the cooling device causes the wire coil springs to reach "a temperature at which the designed deformation of the spring will be less than the elastic limit of the wire.

19. The apparatus according to claim 17, characterized in that: T the heating apparatus increases the temperature of the wire to a range of about 232 ° C to 260 ° C (450 ° F to 500 ° F).

20. The apparatus according to claim 19, characterized in that: the cooling apparatus in a rotating carrousel which receives springs of the rolling forming device.