Beds – Support for users body or part thereof – Spring containing
Reexamination Certificate
2001-06-19
2003-07-15
Trettel, Michael F. (Department: 3673)
Beds
Support for users body or part thereof
Spring containing
C005S720000
Reexamination Certificate
active
06591436
ABSTRACT:
BACKGROUND OF THE INVENTION
This invention relates generally to spring assemblies for mattresses, cushions and the like, and, more particularly, to a method and system for making a string of connected individually pocketed coil springs for mattresses, cushions, spring units and the like.
Pocketed coil springs are often referred to as a Marshall construction in which each coil spring is encased within its own fabric sack or pocket. The sack or pocket is typically defined between two plies of a fabric strip connected together at intervals along transverse lines spaced along the strip. The two-ply fabric strip is generally formed by folding a strip of double width fabric upon itself along a longitudinal centerline, leaving the overlapped plies along the unjoined opposite edges of the strip to be connected to each other along a longitudinal seam to close the pockets defined between the transverse lines of connection after the springs are inserted between the plies.
A variety of techniques have evolved for the manufacture of pocketed springs, some contemplating the creation of the pockets within the fabric plies prior to insertion of the wire spring and others contemplating the insertion of compressed wire springs between the plies of the strip and the subsequent creation of the pockets by stitching or otherwise joining the two plies to each other along transverse lines between adjacent springs. Irrespective of the technique used, the fabric is closed around the spring after the insertion of the spring, usually by stitching or welding the two plies together along a line parallel to the free edges of the plies. Joining the plies together by stitching has largely been replaced in more recent times by the use of a heat sensitive fabric and ultrasonic welding techniques. Examples of known systems and techniques for manufacturing strings of pocketed coil spring are disclosed in U.S. Pat. Nos. 4,439,977; 4,234,983; and 5,613,287, each of which are incorporated herein by reference.
Specifically, in U.S. Pat. No. 4,439,977, a method and apparatus are disclosed for making coil springs enclosed within individual pockets in an elongate fabric strip comprised of two overlying plies capable of being thermally welded together. The fabric strip is fed along a guide path during which compressed springs are inserted between the plies with the axes of the springs substantially normal or perpendicular to the planes of the plies. Thereafter, the fabric plies are thermally welded together longitudinally and transversely while the spring remains compressed to form a string of pocketed coils. After thermal welding, the pocketed coils are passed through a turner assembly during which the springs are reoriented typically about 90° within the fabric pockets to positions wherein the axes of the springs are transverse to the fabric strip.
In general, known systems and methods for producing strings of pocketed coil springs have not been completely satisfactory due in large part to the difficulties in handling and processing the fabric and springs in a mass production, efficient environment. The ability to process, manipulate, advance and incorporate the fabric and springs into a string in an efficient, quality-controlled manner and without operator intervention is crucial to such a system and method. In some instances, the fabric may become tangled or difficult to neatly feed and advance which requires operator correction and down time.
One additional disadvantage of the method of manufacturing pocketed coil springs shown in U.S. Pat. No. 4,439,977 is that during the turning process, springs tend to become entangled or hooked together and do not achieve their proper positions. As such, additional and costly labor is required to reorient and disentangle the springs to place them into their desired configurations and orientations. Even if the springs do not become entangled or hooked, difficulties may still arise in correctly aligning them to their desired positions with the longitudinal axes of the springs being substantially parallel to one another and the transverse seams defining individual pockets.
Another common problem with this type of operation is that during the turning of the pocketed springs, whether or not the springs become hooked or entangled and the turning process is successful, the fabric surrounding the spring is often damaged, torn, punctured or the like. In one form, the springs are beaten by paddles as disclosed in U.S. Pat. No. 4,439,977 to effect the turning of the spring within the pocket. Obviously, the repeated beating on the pocket with the paddles may cause significant damage to the fabric material and prove to be unreliable to accurately position the spring within the fabric pocket. When this happens, the damaged pocket should be repaired or removed from the string thereby interrupting the process and requiring significant operator intervention and down time for the production of pocketed coil springs.
Therefore, a need exists for a method and system for forming strings of pocketed coil springs which overcomes the above described disadvantages of the prior art and does not require operator intervention to handle the fabric or springs. Further, the turning of the springs within the pockets for alignment of the spring axes in a generally parallel and ordered arrangement and operator intervention to unhook or disentangle the springs and repair the damaged fabric surrounding the springs are preferably avoided. Further, a need has always existed to provide commercially viable methods and systems for producing strings of pocketed coil springs which are cost and labor effective by requiring a minimal amount of labor intervention and associated resources.
SUMMARY OF THE INVENTION
The present invention overcomes the above described and other disadvantages in the prior art by providing an improved method and system for producing strings of pocketed coil springs which are effective in performance, yet cost effective in that they require a minimum amount of materials and labor. The manner in which the springs are inserted into the fabric, the handling of the fabric and springs, the formation of the pocket, insertion of the springs and operator involvement generally, according to this invention avoid the need for turning or repositioning the springs within the pockets while still providing an efficient and reliable manufacturing system and associated method for reliably producing consistently aligned springs within undamaged fabric pockets.
The present invention preferably begins with the insertion of a compressed coil spring between upper and lower plies of a thermally welded fabric. The present invention is a continuous production process such that the fabric is indexed or pulled past a spring insertion station so that the compressed springs are individually inserted between the plies of the folded fabric at spaced intervals as the fabric passes the spring insertion station. In one aspect of the invention, the fabric is controlled and advanced by spikes which engage the fabric for processing without damaging the fabric.
The springs are maintained in a compressed configuration between the plies of the fabric while a longitudinal seam is formed in the fabric to join the two plies together proximate free edges of the plies opposite from a longitudinal fold line of the fabric. Since the fabric is a thermally weldable material, preferably the longitudinal seam is formed by a cooperating thermal weld head and anvil combination. After the spring has advanced past the longitudinal weld station, it is allowed to relax and expand within the fabric into an upright position n which a longitudinal axis of the spring is generally perpendicular to the longitudinal seam of the fabric. Preferably, the relaxation and expansion of the springs within he fabric are controlled by a pair of rotating members on opposite sides of the spring according to various alternative embodiments of this invention. The rotating members in presently preferred embodiments may be a pair of oppositely rotating wheels with axes of ro
de Santis Ugo
Graf Roland
Mossbeck Niels S.
Wells Thomas J.
Spuhl AG St. Gallen
Trettel Michael F.
Wood Herron & Evans LLP
LandOfFree
Side seam pocketed coil springs does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Side seam pocketed coil springs, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Side seam pocketed coil springs will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3053011