MXPA98000286A

MXPA98000286A - Handle of comfort grip and procedimie

Info

Publication number: MXPA98000286A
Application number: MXPA/A/1998/000286A
Authority: MX
Inventors: J Marchetti Michael; H Eckert Lee; M Kubicz Edward; Naft Stuart; M Drizos George; Lockshier Roger; Rosander Scott; Mancini Carmine Jr
Original assignee: Hp Intellectual Corp
Priority date: 1997-01-10
Filing date: 1998-01-09
Publication date: 1999-02-24

Abstract

An improved method is provided for integral, composite sleeves having cushioned comfort grips, for household items such as electric steam irons, comprising a first step of injection molding a one piece mango substrate of a resinous composition strong, rigid, having the desired predetermined shape and design, including a depressed envelope area corresponding to the handle area, which will be held by the hand of the end user of the item. The method of the present invention comprises a second step of injection molding an integral, outer, soft, contoured layer of enveloping foam foam, depressed from the rigid plastic handle substrate, to form a comfortable, compressible, soft grip surface area. of the composite material handle for coupling with the user's hand

Description

HANDBOOK OF D EARING LIKE DI DAD AND PROCED I I I DESCRI PCIÓ N OF THE I NVENCÓN The present invention relates to improving the comfort and feel of handles of devices such as household articles, more particularly electric steam irons and similar devices, which are held and guided by the hand of the user, sometimes for extended periods. It is known to provide the handles of household articles, such as electric irons, with foam rubber or sponge rubber covers for cushioning the grip and / or for other purposes, and reference is made to U.S. Patents 2, 324,226 (M urphy) and 2,639, 521 (Rickettson). Murphy Patent 2,324,226 refers to sponge-type rubber covers, such as sleeves, which are forced onto the handle of a wide pl as a cushion grip. Such covers are not satisfactory as they must be produced, separately from the iron, and must be applied to the iron handle, and they can be separated, damaged or lost. Rickettson Patent 2,639,521 discloses a sponge rubber or foam rubber pad, which is formed in a manner separate from the handle of a board, and then adheres to the handle, such as through hone cement, to facilitate the use of the iron. As with the M urphy patent, the Rickettson foam pads must be produced, separately, from the plate, and then they must be adhered to the handle in a predetermined manner. U.S. Patent 4,837,892 (Lo), discloses a cushioned handle for articles such as electric hair tubes, comprising rigid molded plastic handle halves onto which rubber or elastomer overlapping surface portions are molded to form molded mango halves of composite materials, which are then applied to the articles and connected to each other through front and rear penetration screw fasteners. The overlapping portions of rubber are secured to the rigid plastic handle ridges through the penetration of the rubber into the openings or holes in the handle halves during the mousse passage of the overlapping portions on the handle halves. However, this procedure presents serious disadvantages, since the handle halves must be individually molded, then the overlapping / rubber handle halves of composite materials must be individually molded, and then the handle halves of composite materials must be applied. to the article and join through penetration screw fasteners. The present invention relates to an improved process for the production of integral handles, of mixed materials having cushioned comfort grips for electrical articles, such as electric steam irons comprising a first step of providing, such as through molding by injection, a one-piece handle substrate of a rigid, strong plastic composition having the desired predetermined shape and design, including a depressed envelope area corresponding to the area of the handle, which will be held by the handle of the handle; end user of the article. The method of the present invention comprises a second step of injection molding, such as a double activation or overmolding, of a contoured, smooth, integral external layer of resin with foam to the wrapping area, depressed of the rigid plastic handle substrate, to form a comfortable, compressible, soft grip surface area of the composite material handle for engagement by the user's hand. The composite handle is completely formed through the two-step process of the present, ready to be attached to the predetermined article in a conventional manner.

In the attached drawings: Figure 1 is a top view, in partial section, illustrating a handle for a steam iron, with portions of the rigid plastic handle substrate in the depressed wrapping areas that are shown in dotted lines, where they are overlapped by the foam resin cushion grip, and with other portions of the substrate of the rigid plastic handle being exposed through the removal of the foam resin cushion grip; and Figure 2 is a side view of the composite sheet handle of Figure 1. Figure 1 illustrates a composite handle 10 designed to be attached to the housing of a conventional electric steam iron. The handle 10 has a molded rigid plastic substrate 1 1 having generally exposed front and rear surface portions 12 and 13, respectively, connected through a generally depressed skeleton structure 14. In the illustrated embodiment, the front surface portion 12 of the steam iron shank 10 is molded with a depression 22 adapted to receive a temperature control wheel and containing a hole 25 adapted to receive a screw to attach the handle to the housing. The iron. Also, the portion 12 is molded with openings 23 and 24 to adapt activation buttons for a steam thrust and for a water spray, respectively. The connecting structure 14 has a horizontal base structure in the shape of + - comprising a vertically wide rib 15 and a horizontally wide continuous rib 16 and a plurality of closely spaced fin members 17, integrally molded with ribs 15 and 16 for providing a handle substrate 14, which is relatively light in weight, due to the plurality of spaces or air slots 18 between the vanes 17, and still has excellent strength in all directions. The rear surface portion 13 of the rigid substrate 11 in the illustrated embodiment is molded with a lower central extension flange 26 provided with a hole 27 for receiving a joint screw to secure the handle to the plate housing, and with a pair opposite of internally threaded depressions 28 and 29 to receive the back cover joining screws. The composite handle 10 of Figures 1 and 2 also comprises an outer layer of molded foam resin 20, which is injection molded onto the rigid plastic substrate 11 towards its depressed wrapping areas 19, corresponding to the area of the handle , which will be held by the user, including the rest areas of the thumb 21. This is achieved by using the rigid plastic substrate 1 1 as a mold core, supported within the mold halves, which provide an envelope injection cavity corresponding to the depressed areas of the substrate, which are to be filled with the foam resin layer 20. The injection cavity is then filled at low pressure with a fl exible foam forming resinous composition, which contains or generates a blowing agent, such as carbon dioxide gas, and is cured. to form the outer layer of foam resin of smooth, enveloping, compressible surface 20, including the gripping areas of the thumb 21. The composite handle 10 is substantially ready to join the electric steam iron after the removal of the mold, after the total cure. The smooth outer surface of the foam resin layer 20 in a molded curvature, which conforms to the user's grip and which tapers or moves the outer surfaces of the front and rear areas 12 and 1 3 of the rigid support substrate 11 with which the foam layer 20 confronts the smooth feel and the appearance. The rigid plastic substrate 11 illustrated in the drawings is a preferred substrate as it allows the foam layer to partially expand towards the plurality of envelope grooves 18 of the substrate 11 during the foam-forming expansion and formation of the foam layer., to produce the integration and the union of the envelope. In addition, the compression ability and feel of the foam layer 20 to the user's grip is uniform, since the soft foam layer can be compressed in the wrapping grooves to provide a uniform temporary "give" appearance in all directions Radial, from the foam layer 20 returning to its molded shape when pressure is relaxed by the hand. The comfort grip handle 10 of the present may be made of two different thermoplastic resins, in a normal two step injection molding process. The first step of the manufacturing process is to injection mold the rigid substrate 11 from a high impact resistance resin such as a polycarbonate resin, processed at the recommended molding conditions. After the substrate 11 is molded, it is allowed to cure at room temperature to obtain all the mechanical properties of the molded polycarbonate resin. The second step of the process involves the injection molding of the overmoulded foam layer 20 on and around the polycarbonate substrate 11 by first inserting and supporting the substrate 11 centered within the injection mold. A preferred overmold material (a meltable processable rubber) is a halogenated ethylene ether elastomer with a 60 Shore A durometer. The halogenated ethylene interpolymer elastomer is mixed with an endothermic chemical foaming agent composition before being fed to the screw of the injection molding machine. A preferred foam composition consists of a mixture of sodium salts of carbonic and polycarboxylic acids together with a styrene-ethylene / butylene-styrene block copolymer, a mixture of polyalphamethylstyrene commercially available under the trade name Safoam. FP-40. The foaming agent produces a smooth solid layer around a thin cell core shell within the halogenated ethylene interpolymer elastomer. This creates the desired mattress feeling in the comfort handle. A chemical and physical or mechanical bond is formed between the mixture of halogenated ethylene interpolymer and the polycarbonate substrate during the injection cycle, since the resins are compatible and similar in chemical nature. As the mixture of halogenated ethylene polymer enters the mold and contacts the polycarbonate substrate, the polycarbonate surface layer is momentarily fused and a chemical bond is formed.

The foaming agent begins to activate and decompose on a temperature scale of 165 ° C to 204 ° C (330 ° F to 400 ° F). The processable foaming layer 20 is injection molded at 1 76 ° C (350 ° F). The foaming agent begins the activation in the screw of the injection molding machine. This continues the decomposition through the remainder of the injection molding cycle and reaches the term before the molding cycle is completed. In order for the foaming agent to work properly, only about 90% of the injection molding cavity is filled with the foam forming composite. The foaming agent expands and creates a fine cellular structure of the halogenated ethylene interpolymer mixture to fill the remainder of the mold cavity. The overmolding material does not completely fill the interior of the substrate since the foaming agent does not create sufficient pressure to force the halogenated ethylene polymer to fill the grooves 1 8 between the ribs 1 7 in the substrate 1 1. Once the molding cycle is completed, the finished handle is removed from the mold and allowed to cure completely. The rigid plastic substrate 1 1 of the drawings may be provided with grooved, cutting, dovetail cutting or other integration areas on adjacent depressions between the foam layer 20 and the exposed front and rear surface areas 1 2 and 1 3, respectively, of rigid substrate and / or below and adjacent to the resting areas of the puller finger 21. Such integration areas provide an additional peripheral manual closure between the foam layer 20 and the substrate 1 1 to prevent any relative movement between them during the entire life of the article. The rigid plastic substrate may have a structure different from that illustrated in the drawings herein. For example, the depressed area of the rigid substrate may be a hollow tubular section, preferably provided with holes or separate surface openings to admit some of the foam-forming composition and provide anchoring points for the formed foam layer. It will be apparent to those skilled in the art that the handle substrates 11 of the present invention are preferably injection molded from thermally stable, high impact resistant resinous molding compositions conventionally used for this purpose. Preferred thermoplastic resins are polycarbonates, including polymer blends of acrylonitrile lo-butadiene-styrene (ABS). It will also be apparent to those skilled in the art that a variety of low durometer thermoplastic resinous foam resinous compositions are suitable for use as injection molding compositions to form the compressible foam layer 20 herein. Preferably, the foam resin is one that is chemically compatible with the substrate resin, and the foam formation reaction is endothermic to prevent excessive heating and softening of the substrate 1 1. A preferred foam-forming composition is a halogenated ethylene ether elastomer composition incorporating a carboxylic acid salt blowing agent composition-Safoam FP-40 polymer mixture, which generates carbon dioxide during its passage. of slow expansion at low pressure. A preferred halogenated ethylene ether elastomer composition is commercially available from DuPont under the tradename "Alcryn". Other conventional foam-forming compositions that produce an integral layer, a cell core and a high weight-strength ratio are also suitable. Such compositions are commonly based on thermoplastic elastomeric polymers such as vinyl polymers, polyurethane resins and olefinic polymers and copolymers.

The present specification relates to the outer surface of the layer of the foam layer 20 as being integral and isa, this means that the layer 20 has a continuous outer layer, devoid of open cells, and formed before the expansion is completed. . If desired, the outer surface of said layer can be molded to have a textured and patterned feel or appearance, imparted by the surface of the mold.

Claims

REI VI N D I CACI O N ES 1 . A process for producing a composite handle for a domestic article, which is strong, light in weight and has a compressible wrap-around grip portion, which is comfortable to the user's hand, characterized in that it comprises the steps of: a ) provide a rigid, lightweight handle substrate having a wraparound section in a grip area of the handle that is intended to be enclosed within the user's hand. b) inserting the substrate into a mold by injection as a core surrounded by a mold cavity enclosing the grip area of the substrate; c) injecting a resinous foaming molding composition into the mold cavity and curing to form a compliant surrounding layer of resinous foam surrounding and bonding to the grip area of the rigid handle substrate, and d) removing the composite handle from the injection mold.
2. The method according to claim 1, characterized in that the enveloping section of the handle substrate comprises a depressed grip area.
3. The method according to claim 1 or 2, characterized in that the handle substrate has a gripping area comprising a horizontal base structure configured + - integral with a plurality of closely spaced vertical fin members, whereby the composition The foam-forming resinous molding composition injected in step (c) of claim 1 is partially expanded towards the spaces between the fin members to improve the bond between the rigid substrate and the resinous foam layer.
4. The method according to claim 1, characterized in that the composite handle comprises rigid outer surface portions adjacent to the grip area.
5. The method according to claim 1, characterized in that it comprises injection molding the rigid handle substrate of step (a).
6. The method according to claim 5, characterized in that it comprises molding by injection the mango substrate from a thermally stable resinous molding composition with high impact resistance.
7. The process according to claim 5, characterized in that the resinous molding composition comprises a polycarbonate resin or an acrylonitrile-butadiene-styrene polymer.
8. The method according to claim 1, characterized in that the foam-forming resinous composition of step (c) comprises a synthetic thermoplastic elastomeric polymer.
9. A handle of composite material for a domestic article, which is strong, light in weight, and comfortable for the user's hand, characterized in that it comprises a rigid handle substrate molded of a resinous composition, and having exposed surface areas adjacent to it. a depressed enveloping grip area, and having a continuous wrap layer of compressible resinous foam, which is attached to the substrate to provide a comfortable grip for the article, has molded into the depressed grip area.
10. The handle of composite material, according to claim 9, characterized in that the depressed grip area of the rigid substrate comprises a horizontal base structure configured + - integral with a plurality of closely spaced vertical fin members, the resinous foam layer being expanded to a certain degree towards the spaces between the vertical fin members to join the foam layer to the substrate. eleven .
The handle of composite material, according to claim 9, characterized in that the substrate is made of a thermally stable resinous composition, high impact resistance.
12. The handle of composite material, according to claim 1, characterized in that the rigid substrate comprises a polycarbonate resin.
13. The handle of composite material, according to claim 1, characterized in that the rigid substrate comprises an acrylonitrile-butadiene-styrene.
14. The handle of composite material, according to claim 9, characterized in that the resinous foam comprises a synthetic thermoplastic elastomer. RESU M IN D E I NN I N TION An improved method is provided for integral, composite sleeves having cushioned comfort grips, for household items such as electric steam irons, comprising a first step of injection molding a one piece mango substrate of a resinous composition , strong, rigid, having the desired predetermined shape and design, including a depressed enveloping area corresponding to the area of the handle, which will be held by the hand of the end user of the article. The method of the present invention comprises a second step of injection molding an integral, outer, soft, contoured layer of foam resin to the wrapping area, depressed from the rigid plastic handle substrate, to form a comfortable, compressible grip surface area. , soft handle of composite material for coupling with the user's hand.