Dual-blade guide assembly for bidirectional foam slitting

Abstract

A dual-blade guide assembly used with horizontal foam slitting machines, enables bidirectional cutting of polyurethane foam blocks by integrating features of two cutting heads into a single, enhanced U-shaped head. The dual-blade guide assembly employs a single dual-blade guide that accepts two blades i.e. a front blade and a rear blade that is supported within the head. A blade guide holder, positioned on the inside of the U-shaped head, secures the dual-blade guide and is configured to be opened, allowing insertion of the rear blade into the guide.

Description

DUAL-BLADE GUIDE ASSEMBLYFOR BIDIRECTIONAL FOAM SLITTINGField of the Invention

[0001] The present invention relates to the field of foam processing machinery and more specifically to horizontal slitting machines designed for cutting polyurethane foam blocks into sheets for applications such as furniture, packaging, and mattresses.Background

[0002] Horizontal foam slitting machines play a critical role in industries requiring high-volume production of polyurethane foam sheets, such as furniture, packaging, and mattress manufacturing. Conventional single-blade slitters operate by driving a foam block, via a conveyor or moving table, through a tensioned blade guide which supports the tensioned blade. The tensioned blade cuts the sheet during a forward pass. However, the process demands stopping before the blade guide exits the slit in the foam block to prevent deformation and misalignment at the trailing edge. As the blade approaches the block’s back end, the lack of foam support beyond that point requires deceleration; without this, the guide’s cutting forces push the foam backward, deforming the edge. If the guide exits, and the foam rebounds, the slit often shifts upward, misaligning with the guide’s set position and preventing clean reentry on the return.

[0003] As a result, the single-blade slitter must stop the movement of the foam block after the blade has completely exited the block on the first cut but before the blade guide completely exits. Thereafter, the block must be returned to its starting position so the blade / guide can safely move down to the next index position. The total cycle time, from guide indexing start to indexing down for the next cut, produces just one foam sheet. Thus, the return phase of blade movement offers no productive output, significantly limiting throughput, and increasing production time in high-demand settings.Docket # ESC001 FP303AWO 1

[0004] Alternative high-throughput systems, such as carousel slitting machines, employ a round table with an index zone — where no foam is placed — allowing the blade guide to index safely to a new setpoint. These machines can process multiple loaded blocks quickly once started, but their efficiency is hampered by labor-intensive manual loading, requiring multiple operators and forklifts, and slower unloading due to the instability of cut sheets. Consequently, the total batch time for processing N blocks — including loading, cutting, and unloading exceeds the time needed to cut N blocks individually with a more streamlined system.

[0005] Moreover, carousel machines occupy significantly more floor space than linear slitters, posing challenges for space-constrained facilities. Prior art machines, such as horizontal band saws (e.g., U.S. Patent No. 4,608,896, exemplify single-blade linear designs with adjustable heads. However, these designs offer no solution for bidirectional cutting or the wasted return cycle. Similarly, carousel systems fail to optimize overall processing time, labor, and space usage. Other attempts, such as increasing conveyor speed or blade size, risk compromising cut precision or escalate equipment costs, and vertical contour cutters prioritize shaping over efficient sheet production.

[0006] Emerging polyurethane foams, such as viscoelastic foam and closed-cell hydrophilic varieties, present additional challenges for traditional slitting machines. These materials, valued in applications like mattresses and medical padding, exhibit low Indentation Load Deflection (ILD), high tear resistance, and residual tack (stickiness), making them difficult to process, especially when targeting thin sheets. With single-blade slitters, returning the block to its starting position without fully exiting the slit is often impossible due to these properties, as the foam clings and / or deforms.

[0007] The workaround requires cutting completely through the block, allowing the blade guide to exit, then indexing the cutting head above the block height to return to the starting position before indexing down to the next cutting height.Docket # ESC001 FP303AWO 2This “up and over” process lengthens cycle time with each sheet, as the slitter must perform additional vertical movements — up to clear the block and down to the next index — further reducing throughput efficiency.

[0008] Moreover, prior art teachings in single-blade linear cutting designs typically feature adjustable heads that offer no solution for bidirectional cutting, the wasted return cycle, or the processing of sticky, low-ILD foams. Carousel systems, while faster for batch cutting, fail to optimize overall processing time, labor, and space usage, and do not address thin-sheet challenges with newer foams. Other attempts, such as increasing conveyor speed or blade size, risk compromising cut precision or escalate equipment costs, and CNC contour cutters prioritize shaping over efficient sheet production. These limitations highlight a persistent need for new and more efficient, solutions for cutting foam blocks.Brief Description of the Figures

[0009] The accompanying figures, where like reference numerals refer to identical or functionally similar elements throughout the separate views and which together with the detailed description below are incorporated in and form part of the specification, serve to further illustrate various embodiments and to explain various principles and advantages all in accordance with the present invention.

[0010] FIG. 1A illustrates a perspective view of a head assembly as used with the bidirectional foam splitting machine.

[0011] FIG. IB illustrates a left-side magnified view of the horizonal foam splitting machine in accordance with an embodiment of the invention.

[0012] FIG. 1C illustrates a right-side magnified view of the horizonal foam splitting machine in accordance with an embodiment of the invention.

[0013] FIG. 2 is an exploded view illustrating the split bushing system.Docket # ESC001 FP303AWO 3

[0014] FIG. 3 is an exploded view illustrating the configuration of the front blade and rear blade as used with the drive assembly.

[0015] Skilled artisans will appreciate that elements in the figures are illustrated for simplicity and clarity and have not necessarily been drawn to scale. For example, the dimensions of some of the elements in the figures may be exaggerated relative to other elements to help to improve understanding of embodiments of the present invention.Detailed Description

[0016] Before describing in detail embodiments that are in accordance with the present invention, it should be observed that the embodiments reside primarily in combinations of method steps and apparatus components related to a dual-blade guide assembly for bidirectional foam splitting. Accordingly, the apparatus components and method steps have been represented where appropriate by conventional symbols in the drawings, showing only those specific details that are pertinent to understanding the embodiments of the present invention so as not to obscure the disclosure with details that will be readily apparent to those of ordinary skill in the art having the benefit of the description herein.

[0017] In this document, relational terms such as first and second, top and bottom, and the like may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. The terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. An element proceeded by “comprises ...a” does not, without more constraints, preclude the existence of additional identical elements in the process, method, article, or apparatus that comprises the element.Docket # ESC001 FP303AWO 4

[0018] Embodiments of the present invention are directed to a dual-blade guide assembly for use in horizontal foam slitting machines. A need for the present invention has resulted from industry demand. The dual-blade guide assembly, as described herein, is used in a foam slitting machine that doubles throughput by utilizing both forward and reverse passes to cut foam block. This new machine and processes reduce total processing time for cutting multiple blocks while maintaining a cut quality despite foam rebound. Moreover, the dual-blade guide assembly helps to minimize floor space and labor dependency, all while preserving operational simplicity and precision.

[0019] FIG. 1 A illustrates a perspective view of a U-shaped head as used with the bidirectional foam splitting machine. FIG. IB illustrates a left-side magnified view of the horizonal foam splitting machine in accordance with an embodiment of the invention. FIG. 1C illustrates a right-side magnified view of the horizonal foam splitting machine in accordance with an embodiment of the invention. Thus, various embodiments of the present invention are directed to a dual-blade guide assembly used with horizontal foam slitting machines. The dual-blade guide assembly enables bidirectional cutting of polyurethane foam blocks by integrating features of two separate cutting heads into a single, enhanced U-shaped head. As described herein, the horizontal slitter employs a single dual-blade guide that houses and accepts two blades — a front blade and a rear blade that are both supported within the head. A blade guide holder, positioned on the inside of the U-shaped head, secures the dual-blade guide and is configured to be opened, allowing insertion of the rear blade into the guide.

[0020] With reference to FIG. 1A, FIG. IB, and FIG. 1C, these figures illustrate various views of a dual-blade guide foam cutting machine 100a, 100b, 100c configured for bidirectional cutting of foam block. The cutting machine 100a, 100b, 100c includes a dual-blade guide assembly 125 that employs a tensioning system to maintain high tension of the blade guide assembly, enabling the blade guide to counteract cutting forces and hold the front and rear blades steady duringDocket # ESC001 FP303AWO 5forward and reverse cutting passes. The assembly includes a tensioning rod 101, captured and aligned within a lower portion of a U-shaped cutting head 103, which is constructed as a heavy steel weldment designed to flex resiliently when the guide is under tension. The U-shaped head 103 comprises a top weldment 102, an outer head weldment 104 and an inner head weldment 105 each joined to form a robust, unitary structure capable of supporting the tensioned dual-blade guide assembly 125. A compression strut 106 is bolted across the interior of the U-shaped head 103 that works to counteract compressive forces induced by the tensioned dual-blade guide assembly 125. This enhances the guide’s stability and ensures precise blade positioning during bidirectional cutting of foam block. A wheel plate 107 covers the lower portion of the inner head weldment 105.

[0021] Those skilled in the art will recognize that the U-shaped head 103 supports the high tension created by the dual-blade guide assembly 125. On the outside of the outer head weldment 104, the tensioning rod 101 is fitted with a nut 109 and one or more spherical thrust bearings 111. This arrangement enables the tensioning rod 101 to be moved and / or turned to tilt the blade guide assembly 125 that supports both a front blade 113 and rear blade 115. Electric motors 110a, 110b, form and operate as a drive system for the front blade 113 and rear blade 115 respectively, so to move the blades in a circular-type, rotational motion through and around the U-shaped head 103.

[0022] Thus, the U-shaped head 103 is supported on the outside of the outer head weldment 104. Supporting the U-shaped head in this manner allows the U-shaped head 103 to be caried about one or more trunnions 112, 114. This movement enables the U-shaped head to index up / down within its elevating base frame allowing the head to be positioned to desired index location.

[0023] Further, on the inside of the U-shaped head 103, an inside guide holder 116 is formed as a clam shell-style locking clamp fastened to the inner frame portion 105. The inside guide holder 116 captures and holds an inner portion of the tensioning rod 101. A lower holder block in connection with the inside guideDocket # ESC001 FP303AWO 6holder 116 may be opened, once tension is released from the tensioning system 109 by removing a locking bolt from a clamping nut, to allow insertion of the rear blade 115. An upper split bushing 117 is secured to a upper holder block, while a lower split bushing 119 is secured to a lower holder block. The upper split bushing 117 and lower split bushing 119, made from a suitable material for contact with the tensioning rod 101, support the dual-blade guide assembly 125 when the inside guide holder 116 is closed and locked. In conjunction with the spherical thrust bearing 111, the split bushings 117 and 119 allow the tensioning rod 101 to rotate, enabling adjustment of the dual-blade guide assembly 101 to a desired angle. The inner end of the tensioning rod 101 is milled to form a clearance slot, cross-bored at 90-degrees with multiple holes, which secure the dual-blade guide assembly 125 to the rod 101 using pins 127. The tensioning system, employs either a mechanical adjustment, pneumatic and / or hydraulic mechanisms for applying force to maintain high tension of the dual-blade guide assembly 125. This facilitates rapid cutting blade changeovers.

[0024] Thus, an important aspect of the invention is a split bushing system, without which the dual-blade design would not operate properly. This critical component, located on the inside of the inner head weldment 105, consists of a clam shell arrangement with a locking clamp that captures the tensioning rod 101 while allowing the blade guide holder 123 to open fully. The blade guide holder 123 is slotted and cross-bored enabling the insertion and removal of the rear blade 115 into the dual-blade guide holder 123 which is a necessity for the bidirectional cutting process. Thus, the upper split bushing 117 and lower split bushing 119 are essential to the dual-blade guide assembly’s functionality and efficiency.Combined with the mechanical adjustment, pneumatic or hydraulic tensioning, it ensures quick blade changeovers and operational reliability, distinguishing the present invention from conventional foam block slitter type machines.

[0025] FIG. 2 is an exploded view illustrating the split bushing assembly as described herein. The inside guide holder 116 includes an upper clamp block 201Docket # ESC001 FP303AWO 7and lower clamp block 203 that are secured to the U-shaped head using fasteners through clearance holes 204. Clearance holes 204 are used for securing the split bushing assembly to the U-shaped head. An upper split bushing 117 and lower split bushing 119 are positioned within the upper clamp 201 and lower clamp 203 and are used to hold a tensioning rod 101 as described herein. The upper slit bushing 117 and lower split bushing are held and / or clamped together using a plurality of fasteners 205. A pivot bracket 209 is used to hold the upper split bushing 201 and lower split bushing 203 in a fixed position. As noted herein, the lower holder block 203 of the inside guide holder may be opened. Once tension is released from the tensioning system, a locking bolt 207 is removed from the clamping nut 209. This allows insertion of the rear blade.

[0026] FIG. 3 is an exploded view illustrating the configuration of the front blade and rear blade as used with the drive assembly. More specifically, the illustration shows the front blade 113 and rear blade 115 rotated in a circular-like closed loop using pulleys 301, 303 and 305, 307 respectively. The blades are shown as used in connection with the tensioning rod 101 and spherical thrust bearing 111 and motor 118. The dual-blade guide holder 116 works with an upper support guide 126 and lower support guide 128 to enable the blades 113, 115 to move in a precise manner while giving mechanical support during the foam block cutting process.

[0027] The cutting process of using the dual-blade guide assembly involves driving a foam block forward on a conveyor through the front blade to cut a first foam sheet. Thereafter, the U-shaped head moves to the next index position before the block is reversed through the rear blade to cut a second sheet. This process effectively doubles throughput in a single cycle compared to conventional single-blade foam slitter machines. The combination of all these components of the dual-blade guide assembly viz. the adjustable tensioning rod, split bushing guide holder, and pneumatic or hydraulic tensioning ensures stability, precision, and operational efficiency across both cutting directionsDocket # ESC001 FP303AWO 8

[0028] Thus, the present invention is directed to a dual-blade guide assembly as used in a foam slitting machine. The use of the dual-blade guide assembly effectively doubles throughput by utilizing both forward and reverse cutting passes. This has the result of reducing total processing time for multiple blocks, including the more difficult newer density foams, while maintaining cut quality despite foam rebound and tackiness. Additionally, it also minimizes floor space and labor dependency, all while preserving operational simplicity and precision. Thus, embodiments of the present invention are directed to a dual-blade guide assembly for horizontal foam slitting machines that utilizes a single dual-blade guide that includes a front blade and a rear blade that is supported within a U-shaped head and where a blade guide holder is positioned on an inside of the U-shaped head for securing the dual-blade guide. The dual-blade guide is configured to be opened, allowing insertion of the rear blade into the guide. The blade guide assembly is designed to enable bidirectional cutting of a polyurethane foam block using both the U-shaped head having both a front blade and a rear blade to provide more efficient cutting.

[0029] In the foregoing specification, specific embodiments of the present invention have been described. However, one of ordinary skill in the art appreciates that various modifications and changes can be made without departing from the scope of the present invention as set forth in the claims below.Accordingly, the specification and figures are to be regarded in an illustrative rather than a restrictive sense, and all such modifications are intended to be included within the scope of present invention. The benefits, advantages, solutions to problems, and any element(s) that may cause any benefit, advantage, or solution to occur or become more pronounced are not to be construed as a critical, required, or essential features or elements of any or all the claims. The invention is defined solely by the appended claims including any amendments made during the pendency of this application and all equivalents of those claims as issued.Docket # ESC001 FP303AWO 9

Claims

We claim:

1. A dual-blade guide assembly for horizontal foam slitting machines comprising:a single dual-blade guide that includes a front blade and a rear blade that is supported within a U-shaped head;a blade guide holder positioned on an inside of the U-shaped head, for securing the dual-blade guide that is configured to be opened for allowing insertion of the rear blade into the guide; andwherein the blade guide assembly is designed to enable bidirectional cutting of a polyurethane foam block using both the U-shaped head having both a front blade and a rear blade to provide more efficient cutting,2. A dual blade-guide assembly as in claim 1, further comprising:a split bushing for supporting a tensioning rod that enables the blade guide holder to fully open.

3. A dual blade-guide assembly as in claim 1, further comprising:a split bushing for facilitating the insertion and removal of the rear blade into the blade guide holder for enabling bidirectional cutting.

4. A dual blade-guide assembly as in claim 2, further comprising at least one trunnion for allowing the U-shaped head to move in a pivoting motion allowing greater cutting versatility.Docket # ESC001 FP303AWO 105. A dual-blade guide assembly for horizontal foam slitting machines comprising: a U-shaped head;a front blade and a rear blade that are both supported within the U -shaded head;a guide for supporting the front and rear blade;a blade guide holder, positioned on an inside of the U-shaped head, for securing the dual-blade guide; andwherein the blade guide holder can be opened for allowing insertion of the rear blade into the guide.

6. A dual blade-guide assembly as in claim 5, further comprising:a split bushing for supporting a tensioning rod that enables the blade guide holder to fully open.

7. A dual blade-guide assembly as in claim 5, further comprising:a split bushing for facilitating the insertion and removal of the rear blade into the blade guide holder for enabling bidirectional cutting.

8. A dual blade-guide assembly as in claim 5, further comprising at least one trunnion for allowing the U-shaped head to move in a pivoting motion allowing greater cutting versatility.

9. A dual-blade guide assembly for use in a horizontal foam slitting machine comprising:a blade guide holder that includes both a front blade and a rear blade that are supported within a U-shaped head;Docket # ESC001 FP303AWO 11a tensioning rod connected to the blade guide holder enabling the blade guide holder to tilt the front blade and rear blade to a desired angle; and wherein a blade guide holder is configured to be opened, allowing insertion of the rear blade into the blade guide and where the front blade and rear blade enable bidirectional cutting of a polyurethane foam block through the U-shaped head.

10. A dual blade-guide assembly as in claim 9, further comprising:a split bushing for supporting a tensioning rod that enables the blade guide holder to fully open.

11. A dual blade-guide assembly as in claim 9, wherein further comprising: a split bushing for facilitating the insertion and removal of the rear blade into the blade guide holder for enabling bidirectional cutting.

12. A dual blade-guide assembly as in claim 9, further comprising:at least one trunnion to hold the exterior of the U-shaped head for indexing vertically and to allow for the insertion of the rear blade.Docket # ESC001 FP303AWO 12

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