|Publication number||US2510383 A|
|Publication date||Jun 6, 1950|
|Filing date||Nov 13, 1946|
|Priority date||Nov 15, 1945|
|Publication number||US 2510383 A, US 2510383A, US-A-2510383, US2510383 A, US2510383A|
|Inventors||Dalgleish James White|
|Original Assignee||Pye Ltd|
|Export Citation||BiBTeX, EndNote, RefMan|
|Patent Citations (8), Referenced by (29), Classifications (16)|
|External Links: USPTO, USPTO Assignment, Espacenet|
J 0 J. w. DALGLEISH 2,510,333
METHOD OF CUTTING OR TRIMMING THERMOPLASTIC MATERIALS Filed Nov. 13, 1946 jg. 5 7/94. Inventor 2m: 6/1 (g/WM fi M254;
Attorney Patented June 6, 1950;
2,510,383 mn'rnoo or oor'rmo on TRIMMING rnnmuormsrro MATERIALS James White Dalgleish, Cambridge, England, as-
slgnor to Pye Limited, Cambridge, England, a British company Application November 13, 1946, Serial No. 709,659
In Great Britain November 15, 1945.
The invention relates to a method of cutting or trimming thermo-plastic materials, particularly in'sheet form. Such materials are being used in the manufacture of purses, tobacco pouches and the like. The present invention has for an object to enable such materials to be cut and to present a smooth moulded edge of superior finish.
According to the present invention, the method of cutting thermo-plastic materials consists in closing together upon the material two electrodes of the desired form to which a high frequency voltage of suitable amplitude and frequency for,
heating the material is applied, switching off the high frequency power before dielectric breakdown of the material occurs, and then continuing the closure of the electrodes to sever the material completely or so as to leave only a very thin flash which can be readily pulled away for trimmed off in a second operation. The electrodes are made with the desired shape and contour to produce the desired cut with the edge of the desired shape.
In order that the invention may be more clear- 1y understood, reference will now be made to the accompanying drawings, in which:
Fig. 1 shows diagrammatically an'arrangement according to the present invention for cutting thermo-plastic material, at the sta e before the cutting has commenced.
Fig. 2 shows the arrangement partly cut.
Fig. 3 shows the final stage where the sheet is cut;
Fig. 4 shows a modification. Referring to the embodiment shown in Figs. 1, 2 and 3, the sheet I of thermoplastic material to be cut is placed between two linear electrodes 2 and 3 having the form of the cut required. A cross-section through the electrodes is such that when the two cutting edges thereof are in contact the portion of the plastic material enclosed between the. adjacent shaped portions of the electrodes has the desired contour and form of the finished edge. Thus, as shown in the drawings, theelectrodes 2 and 3, which are shaped to produce an edge of rounded form,.'have an approximately V-shaped cross-section with the portions adjacent the apices thereof which are directed towards the edge to be finished being curved to produce a rounded edge 4 (see Fig. 3) when the electrodes are in contact. For other forms of edge. corresponding alterations would be made in the shape of theelectrodes.
The electrodes are mounted in a press, and are connected to be supplied with a high frequency with the sheet voltage of suitable amplude and frequency for heating the material of the sheet I. The drawing shows the bottom electrode3, fixed and the upper electrode 2 moved by an air-operated ram 5. The supply of high frequency energy to the electrodes is controlled by the switch contacts 6, l, the movable contact 1 of which isnormally held in engagement with the contact 6 by the spring 8. The rod 9, extending from the movable contact 1 passes out through an aperture in the casing Ill, within the switch mechanism is located in a direction substantially parallel to the direction of movement of the ram 5 and is provided with a head H at its lower end. Embracing the rod 9 is the apertured or forked end IQ of an arm l3 carried by its collar it from the ram 5 so that at a predetermined advanced position of the ram 5, the end i2 of the arm engages the head ll of the rod 9 and moves the contact I out of engagement with the contacts 5 to open the circuit supplying the high frequency energy to the electrodes 2 and 3. The position at which the contact I is opened may be adjusted by adjusting the position of the collar M along the ram 5, a set screw l5 being provided for securingthe collar in the adjusted position.
Upon closing the press; the electrodes 2 and 3 are brought into contact with the surface of the material (see Fig. 1) and the high frequency voltage is applied, the material thereby being heated to the softening point. When the material softens, the electrodes close together until they reach the position shown in Fig. 2 when the contact I is opened to cut off the supply of high frequency energy to the electrodes. The arm I3 is so adjusted that the high frequency energy is automatically switched ofi before dielectric breakdown of the material I occurs. electrodes then continues until the electrodes meet or nearly meet (see Fig. 3) thereby formingthe edge to the desired shape and severing the material completely or leaving only a very thin flash which can be readily pulled away or trimmed oil in a second operation.
A feature of the invention lies in the sequence of operations whereby, in one operation of the press, the material is first heated to a plastic .condition by the high frequency energy, and the high frequency energy is switched off automatically before the completion of the melting and severing operation.
Although particularly applicable to the cutting or trimming of thermoplastic sheet materials, the
invention may also be applied to the cutting of thermoplastic woven fabrics in order to produce a Closure of the non-fraying selvedge. Moreover, as shown in Fig. 4 by inserting two sheets of material Ia, lb,
between the electrodes 2 and 3, the sheets may be simultaneously trimmed and welded together at the edge 4a. Furthermore, the invention may also be applied to the cutting of rods or tubes in order to produce a smooth moulded finish to the cut.
1. Method of cutting thermo-plastic materials, which consists in positioning the material to be out between two electrodes, applying high frequency energy to the electrodes to generate heat in the material therebetween, moving the electrodes towards each other during the application of the high frequency energy to cause them to enter the material, interrupting the supply of high frequency energy before dielectric break-- down of the material occurs and thereafter continuing the closure of the electrodes.
2. Method of cutting and simultaneously welding together a plurality of layers of thermo-plastic material which consists in positioning the layers between two electrodes, applying high frequency energy to the electrodes to generate heat in the material therebetween, moving the electrodes towards each other during the application of the high frequency energy to cause them to enter the material, interrupting the supply of high frequency energy before dielectric breakdown of the material occurs and thereafter continuing the closure or the electrodes to sever the material and weld together the cut edges of the layers of material.
3. Method of cutting thermo-plastic materials and moulding the cut edges thereof to a desired configuration which consists in positioning the material between two electrodes, applying high frequency energy to the electrodes to generate heat in the material therebetween, commencing the cutting operation while the material is hot and completing the cutting operation while extracting heat from the material and moulding the out edge to the desired configuration.
JAMES WHITE DALGLEISH.
REFERENCES CITED The following references are of record in the file of this patent:
UNITED STATES PATENTS
|Cited Patent||Filing date||Publication date||Applicant||Title|
|US1388762 *||Aug 9, 1920||Aug 23, 1921||Miller Rubber Co||Manufacture of rubber bathing-caps|
|US1668782 *||Sep 20, 1924||May 8, 1928||Paramount Rubber Cons Inc||Method of making rubber bladders|
|US2232640 *||Dec 23, 1938||Feb 18, 1941||Protex Products Company||Method of making articles from heat fusible sheet material|
|US2293178 *||Jan 9, 1942||Aug 18, 1942||Cameron Machine Co||Art of severing thermoplastic webs|
|US2324068 *||Jun 18, 1941||Jul 13, 1943||Compo Shoe Machinery Corp||Electrostatic bonding apparatus|
|US2328063 *||May 10, 1940||Aug 31, 1943||Celanese Corp||Process of cutting fabric|
|US2354714 *||Oct 17, 1941||Aug 1, 1944||Budd Wheel Co||Method and apparatus for heating thermoplastics|
|US2425388 *||Apr 23, 1943||Aug 12, 1947||Oestricher Bernard||Plastic inner sole|
|Citing Patent||Filing date||Publication date||Applicant||Title|
|US2628412 *||May 27, 1950||Feb 17, 1953||Hava Dev Co Inc||Method and apparatus for cutting synthetic fiber fabrics|
|US2632724 *||Jan 10, 1948||Mar 24, 1953||L A Goodman Mfg Company||Method for bonding hollow plastic bodies|
|US2638963 *||Mar 31, 1949||May 19, 1953||Us Army||Apparatus for dielectric fabrication|
|US2649672 *||May 19, 1950||Aug 25, 1953||Wingfoot Corp||Method of wrapping in multi-ply material|
|US2657425 *||May 12, 1951||Nov 3, 1953||Price S Patent Candle Company||Apparatus for making wax candles|
|US2681296 *||Aug 13, 1951||Jun 15, 1954||Frank G Dobbs||Manufacture of sealed enclosures|
|US2686556 *||May 31, 1950||Aug 17, 1954||Gerber Eugene||Machine for sealing thermoplastic materials|
|US2727128 *||Nov 10, 1953||Dec 13, 1955||Jaye Corp||Device for cutting apertures in cellular thermoplastic|
|US2730160 *||Oct 16, 1951||Jan 10, 1956||British Xylonite Co Ltd||Apparatus for forming joints between thermoplastic sheets|
|US2759524 *||Jan 17, 1952||Aug 21, 1956||Ford C Davis||Methods and apparatus for forming welded joints in heat-fusible plastic material|
|US2982456 *||Mar 26, 1957||May 2, 1961||Gen Motors Corp||Method for severing thermoplastic materials|
|US3047991 *||May 2, 1961||Aug 7, 1962||Weldotron Corp||Impulse sealing apparatus|
|US3086901 *||Mar 24, 1960||Apr 23, 1963||Edgecraft Co||Method of making endless printing tapes|
|US3140039 *||Aug 3, 1960||Jul 7, 1964||Fmc Corp||Flexible wall container|
|US3144372 *||Jun 8, 1959||Aug 11, 1964||Peterson Electronic Die Co Inc||Method of heat and tear sealing polyurethane foam material to thermoplastic film|
|US3368692 *||Jan 20, 1964||Feb 13, 1968||Coniker Entpr Inc||Pleated pocket forming method|
|US3483777 *||Nov 1, 1962||Dec 16, 1969||Xerox Corp||Information storage and retrieval employing thermal perforation of the record member|
|US3673300 *||Jun 23, 1970||Jun 27, 1972||Usm Corp||Method for rounding welded edge seams|
|US3809306 *||Mar 2, 1972||May 7, 1974||Usm Corp||Apparatus for rounding welded edge seams|
|US4451721 *||Jul 26, 1982||May 29, 1984||S. C. Johnson & Son, Inc.||Method for high frequency welding flangeless thermoplastic shells|
|US4820468 *||Mar 22, 1985||Apr 11, 1989||Hartig Martval J||Method for making welded hollow plastic plate heat exchangers|
|US4940557 *||Dec 27, 1988||Jul 10, 1990||Hashmoto Forming Industry Co., Ltd.||Method of manufacturing molding members|
|US4960479 *||Jan 22, 1990||Oct 2, 1990||Delta Kogyo Co., Ltd.||Method for manufacturing an automobile sunvisor|
|US5159865 *||Feb 11, 1992||Nov 3, 1992||The Boeing Company||Vibration driven hot knife for separating bonded assemblies|
|US5841107 *||Jun 17, 1993||Nov 24, 1998||Riva; Franca||Sheet perforation apparatus with heated needles and a complementary mold|
|US6475878 *||Aug 9, 2001||Nov 5, 2002||Dusan Slepcevic||Method for singulation of integrated circuit devices|
|US6820784 *||Dec 21, 2001||Nov 23, 2004||Eastman Kodak Company||Method of cutting a laminated web and reducing delamination|
|DE886073C *||Dec 25, 1951||Aug 10, 1953||Hagedorn & Co Ag A||Kunststoffplaettchen od. dgl. aus thermoplastischem Kunststoff und Verfahren zu dessen Herstellung|
|DE1156550B *||Aug 29, 1959||Oct 31, 1963||Lonza Ag||Verfahren zur Herstellung von Flaechengebilden aus Schaumkunststoffen unter Anwendung von spanabhebenden Werkzeugen|
|U.S. Classification||156/251, 264/248, 264/163, 264/451, 156/274.4, 219/383, 219/780, 83/51, 83/16, 219/774|
|International Classification||B26F3/06, B29C65/04|
|Cooperative Classification||B29C65/04, B26F3/06|
|European Classification||B29C65/04, B26F3/06|