WO2016016905A2

WO2016016905A2 - Polyurethane for automotive seat damper/grommet fitted to motorcycle seat base

Info

Publication number: WO2016016905A2
Application number: PCT/IN2015/000299
Authority: WO
Inventors: Vikas Pramod TYAGI
Original assignee: Varroc Polymers Pvt. Ltd.
Priority date: 2014-07-31
Filing date: 2015-07-28
Publication date: 2016-02-04
Also published as: WO2016016905A3

Abstract

The invention comprises a damper or seat pad or a grommet at the interphase between the Seat Base and the chassis of an automobile vehicle, that helps to subdue or dampening or dissipating effect of the shocks and rattling sound that emanates from seat base between the Seat Assembly and the chassis of the automobile while the automobile vehicle is running; wherein the damper or the grommet is made from Semi-Rigid Integral-Skin Polyurethane foam, and a method of making the grommet from Semi-Rigid Integral-Skin Polyurethane foam. The invention also comprises a Seat Assembly comprising a damper as described above.

Description

POLYIJRETHANE FOR AUTOMOTIVE SEAT DAMPER/GROMMET FITTED

TO MOTORCYCLE SEAT BASE

FIELD OF INVENTION

This invention relates to Automotive Seat dampers & grommet from Polyurethane (semi-rigid Integral-skin foam) fitted to seat base.

BACKGROUND OF INVENTION Cushion of an automotive is supported by an Automotive Seat Base made of Polypropylene and "damper or grommet", which is subject matter of this invention, is fitted to seat base to give dampening/dissipating effect, shock absorbing effect and to avoid the rattling noise that usually comes from / emanates from the seat of an automotive when the automotive vehicle is running. Damper or grommet is a part concealed below the seat base and provides an interface between the Seat Base and the chassis of the automobile vehicle. It is intended to be used for automotive vehicle mostly in two wheelers. A "damper" is defined by Oxford Dictionary on the link http://www.oxforddictionaries.com/definition/english/damper as "thing that has a subduing or inhibiting effect". A "grommet" for the purpose of this invention, shall be used with the same meaning as given above for "damper" and the words "damper" and "grommet" are used interchangeably throughout this specification for a part that has a subduing or inhibiting effect for the vibrations that get transmitted to the Seat Assembly and/or rattling sound that gets generated on account of these vibrations between the chassis of a running auotomobile and the Seat assembly. The term "Damper" has been used for many other parts that subdue or inhibit adverse effect that arises from contact between many other pairs of different parts in a machine; however, for the purpose of this specification, the term "Damper" is used only to denote the part that helps to subdue or dampening or dissipating effect of the shocks and rattling sound that emanates from seat base between the Seat Assembly and the chassis of the automobile while the automobile vehicle is running. The term "automobile" or "automotive" is also used in this specification to mean "automobile vehicle". The term "Grommet" is also used with various meanings. However, this term has been used for the purpose of this specification with the meaning that is attached to the term "Damper" in this specification. Thus, "damper" and "Grommet" are the terms used interchangeably that denote "Damper" with the above mentioned meaning. "Seat Pad" is a term that is also used alternatively for the same part and with same meaning with which the terms "grommet" or "damper" are used in this specification.

Prior to this invention, since the beginning of the two wheeler automobile industry up to this date, the grommets were and are being made from rubber. Generally EPDM (Ethylene Propylene Diene Monomer) or NR (Natural Rubber) or PVC (Polyvinyl Chloride) is used to make the rubber damper or grommet. The damper or grommet is made as per the size and shape of environmental data of the chassis and the seat base. It is fitted to the seat base during seat assembly and then seat assembly is fitted to the chassis and the damper or grommet rests on the chassis of the vehicle. However, Damper made of rubber has high density and less abrasion resistance and compression set is too high i.e. it will compress only after a certain period and when a significant force gets applied on that.

Further, the steps involved in production of rubber damper or grommet part and its fitment on the seat base comprises several steps, each step adding to the cost of production. The steps include: (a) preparation of Master Batch, wherein the ingredients that make the rubber damper./grommet are added and mixed on Roll mill for up to 22-27 minutes to produce a mixture, a "charge", (b) applying a "Mold Release" to the mold, (c) transferring the charge to the mold as per required quantity at certain temperature depending on the properties of the rubber; which may be about 180-200°C if it is EPDM (Ethylene Propylene Diene monomer ) rubber, (d) closing the mold (f) de-molding after 5-6 minutes curing time, (g), trimming out the extra material, (h) then fitting the same to the seat base, (i) and finally fitting the seat base to the chassis of the vehicle. This elaborate production process makes the product costly and heavier in weight.

There had been a long standing need since several decades for a techno- economically improved Damper / Grommet for automobiles.

SUMMARY OF THE INVENTION: In one embodiment, this invention comprises a damper or a grommet at the interphase between the Seat Base and the chassis of an automobile vehicle, that helps to subdue or dampening or dissipating effect of the shocks and rattling sound that emanates from seat base between the Seat Assembly and the chassis of the automobile while the automobile vehicle is running; wherein the damper or the grommet is made from Semi-Rigid Integral-Skin Polyurethane foam.

In another embodiment, this invention comprises a Seat Assembly for an automobile comprising a Seat Base and a damper or a grommet at the interphase between the Seat Base and the chassis of the automobile; wherein the damper or the grommet is made from Semi-Rigid Integral-Skin Polyurethane foam.

In a further embodiment, this invention also comprises a process of making a Seat Assembly for an automobile comprising a Seat Base and a damper or a grommet at the interphase between the Seat Base and the chassis of the automobile; wherein the process of making the damper or the grommet comprises steps of: (a) spraying a release agent inside a mold, (b) pouring mixture of chemicals, that are required to make polyurethane into the mold, the mixture being in such a proportion that they result in a semi-rigid Integral- skin Polyurethane foam, (c) closing the mould, (d) allowing a period of time for curing, (e) de-molding the part after curing, and (f) trimming out the extra material, (g) make fitment of the part to the Seat Base, and (h) carrying cut fitting of the Seat Base to the chassis of the automobile.

The automobile for which various embodiments of this invention are applied is a two wheeler or a three wheeler.

BRIEF DESCRIPTION OF FIGURES AND LEGANDS

Figure 1.1: General features/structure/design/parts of a Seat Assembly

Seat Foam covered with Rexene (1), Seat Base (2) which is made of PP (Polypropylene) or other equivalent material. Figure 1.2: Cut section of Seat Assembly. (Section in the plane A-A of Figure 1.1)

Seat Cover (3), Seat Foam made of Polyurethane (4), Seat base made of PP (5), Seat Damper or rubber grommet or seat pad: this is made of rubber in prior art, and the same is made of Polyurethane of this invention (6), Seat Locking Pin (7). Figure 1.3: Cut Section of middle part of seat assembly. (Section in the plane B-B of Figure 1.1) Seat Cover (3), Seat Foam made of Polyurethane (4), Seat base made of PP (5), Seat Damper or rubber grommet made of rubber in prior art Seat Damper or Grommet made of Polyurethane of this invention (6)

Figure 2: Damper or Grommet Layout

Illustrative damper or grommet: made of rubber conventionally, made of polyurethane in this invention. Shape and size of the damper may be anything that is meant to serve to provide a dampening/dissipating effect of the shocks and rattling sound that emanates from seat base when the automotive is running.

DETAILED DESCRIPTION OF THE INVENTION

General features/structure/design/parts of a Seat Assembly as visible in a vertical cut section, along the axis/plane "A-A" indicated in Figure 1.1 , is represented by Figure 1.2 that comprise a Damper (6); the damper being a part that connects seat to the chassis meant for dissipating the shocks transmitted by the chassis and to dissipate the rattling sound made by / emanating from the seat when the automobile is running. The damper may be of any geometry /structure that is capable of providing the function of dampening /dissipating of the shocks and sound referred above. The damper is fitted to the seat base by various means. The fitment may be done with the help of adhesive or without adhesive. When fitted with the chassis, the Seat Dampers rest on the chassis of the vehicle and the Seat Base itself is fitted with chassis with locking pin or other locking arrangement at the other end. The Seat Assembly supports and provides anchorage to cushion (4) on which the driver sits. The cushion may, usually be composed of a material that provides a soft and comfortable surface on which a driver can sit while driving. Generally a cushion is filled with a filler. The filler may, without limitations, comprise one or more, including, without limitation, cotton wool, coir or a polyurethane foam covered by a cloth made from various materials. The material of the filler may include, without limitations, a cotton cloth or a Rexene. The covering cloth (Rexene) is fitted on the Seat Base as well as to the filler material by means which achieve/help the fitment, Such a means may include, without limitation, nails, Staple Pin or an adhesive. The Seat Base is generally of PP (polypropylene), ABS (Acrylonitrile butadiene styrene), PA+ABS (Blend of Polyamide and ABS), or other plastic, or other equivalent material in black or natural color.

In the instant invention, Semi-rigid Integral-skin Polyurethane damper or grommet is made by a simplified single step process. The inventive step lies in the fact that although the need for a techno-economically improved Damper had been since several decades and polyurethane with its properties is also known since at least 1993 (US 5,633,289) and although necessity of an improved damper existed long before that use of polyurethane foam for a damper or grommet was never thought of for nearly 20 years, and it is for the first time that this invention made a Damper successfully from Polyurethane foam, and had achieved a complete success to provide a solution to the long standing problem.

The word "mould" or alternatively "mold", as used in this specification means "a shaped cavity used to give a definite form to fluid or plastic material" as given in The free dictionary on the link http://www.thefreedictionarv.corn/mould (as accessed on 7th Dec 2012). Another meaning of this word in biology means fungi. However, the biological meaning is not applicable here. The word "Mould" is British word, the American equivalent of which is "mold" which has both above meanings and is used in this specification to mean "a shaped cavity used to give a definite form to fluid or plastic material".

In the method/process of making of semi-rigid Integral skin Polyuretane damper or grommet of this invention, there is no need of making master batch (i.e. Rubber having vulcanizing agent, activator, accelerator, filler etc) in it, the chemicals (Polyol and Isocyanate) are directly loaded to the machine. Hence, this is a simplified process of production of the damper or grommet. Further, semi-rigid Integral-Skin Polyurethane foam damper or grommet of this invention is more accurate in dimensions, lighter in weight, and fitment to the seat base is simple. The fitment may be done manually or by insert molding or any other simple mechanism.

The instant invention has achieved further cost reduction and improvement in quality. The product of this invention is applicable to the two wheelers, three wheelers, four wheelers and other automotive dampening.

This invention provides a further cost effective dampers or grommet and involves less steps in manufacture.

A damper or a grommet is that part that provides an interphase between the Seat Base and the chassis of the automobile. Ordinarily, this is a separate part that fits on one end with the Seat Base and its other end rests on the chassis. However, many other variations may be thought of wherein, for example, the damper or grommet may be an extension part of the body of the Seat Base that rests on the chassis. Irrespective of detailed structure, damper or grommet is understood, for the purpose of this invention as that part which provides an interphase between the Seat Base and the chassis of the automobile. In one embodiment of this invention the damper or grommet is made from Semi-rigid Integral-skin Polyurethane foam. The type of Polyurethane foam which is described for the purpose of this specification as Semi-rigid Integral-skin Polyurethane foam" is also described in slight variations of the same, such as "a semi-rigid integral skin foam" in US 5633289, "Semi-rigid Polyurethane integral foam" in CA 02290377 (1999) . However, in whatever way it is expressed, a "Semi-rigid Integral-skin Polyurethane foam" is described as and is understood as comprising an integral skin having a low degree of foaming and a core having a high degree of foaming by US 5633289. The same has been described as "materials with compacted edge zones with a given degree of hardness and a much more flexible cellular core, so-called integral foams" in CA 02290377. It is termed as "Integral Skin Polyurethane foam" because polyurethane itself produces thick skin during the process.

In addition to above, the properties of semi-rigid Integral-skin polyurethane foam are light in weight, and are capable of providing high abrasion resistance, good Shock absorbing capacity, elimination of rattling noise, providing comfort to the rider and weather resistance.

In another aspect, the invention comprises a process that comprise steps of: (a) spraying a release agent inside the mold, (b) pouring chemicals by means of a machine required to make polyurethane i.e. Polyol and Isocyanate into the mould in such a proportion that they result in a semi-rigid Integral-skin Polyurethane foam, (c) closing the mould within few seconds after pouring, preferably within 5 seconds, (d) de-molding the part after 5-6 minutes of curing, and (f) trimming out the extra material. Then the part is ready to assemble i.e. fitment to the Seat Base and then Seat Base is fitted to the chassis of the vehicle. The machine used for pouring chemicals may be a high/low pressure polyurethane machine. The release agent used in the illustration is a water/solvent based release agent having base material Wax/Silicon with glossy/mat finish. However, any other release agent may be used which shall achieve the objective of the grommet formed in the mold being released from the mold when mold is opened In one embodiment, the proportions of Polyol and Isocyanate for getting a semi-rigid Integral-skin Polyurethane foam ranges between 100 parts Po!yol: 40-70 parts Isocyanate.

The invention gives following advantages: (a) easy to Process: no master batch preparation is required and no charge preparation required, (b) chemical have better resistance to adverse environmental weathering factors including termite, borer, bacteria resistance, (c) low density (light weight), (d) a time saving process, (e) better in aesthetics, (f) it has no odor / smell, no volatile content emission.

Thus the process of invention is shorter, the product is lighter in weight, requires less time to manufacture, is less costly and gives a qualitatively superior product.

Example 1 :

A mould is prepared of dimensions required for the desired design of the damper, water/solvent based release agent having base material Wax/Silicon with glossy/mat finished is sprayed as release agent inside the mould prepared for making damper. Polyether Polyol was mixed with Isocyanate. Proportions which worked for getting a polyurethane of desired consistency ranged for every 100 parts Polyether Polyol between 65-80 parts of Isocyanate. Mould temperature was controlled between 50-65°C and above mixture of Polyether Polyol and Isocyanate was sprayed with help of a machine inside the mould. Reaction time, Cream time, for polyurethane formation was 7-12, time reqiored to make it tack free was 20-30 sec and De-Moulding time was 250-350 sec.

Mechanical Properties of the Grommet / Damper thus formed were found to be following:

Claims

CLAIMS :

1. A damper or seat pad or a grommet at the interphase between the Seat Base and the chassis of an automobile vehicle, that helps to subdue or dampening or dissipating effect of the shocks and rattling sound that emanates from seat base between the Seat Assembly and the chassis of the automobile while the automobile vehicle is running; wherein the damper or the grommet is made from Semi- Rigid Integral-Skin Polyurethane foam.

2. A Seat Assembly for an automobile vehicle comprising a Seat Base and a damper or seat pad or a grommet at the interphase between the Seat Base and the chassis of the automobile vehicle; wherein the damper or the grommet is made from Semi-Rigid Integral-Skin Polyurethane foam.

3. A process of making a Seat Assembly for an automobile vehicle comprising a Seat Base and a damper or a grommet at the interphase between the Seat Base and the chassis of the automobile vehicle; wherein the process of making the damper or the grommet comprises steps of: (a) spraying a release agent inside a mould, (b) pouring mixture of chemicals, that are required to make polyurethane into the mould the mixture being in such a proportion of the chemicals that they result in a semi-rigid Integral-skin Polyurethane foam, (c) closing the mould, (d) allowing a period of time for curing, (e) de-moulding the part after curing, and (f) trimming out the extra material, (g) make fitment of the part to the Seat Base, and (h) carrying out fitting of the Seat Base to the chassis of the automobile. The process of claim 3 wherein:

a. the release agent is water/solvent based release agent having base material Wax/Silicon with glossy/mat finish.

b. the mixture of chemicals comprises Polyether Polyol mixed with Isocyanate and the proportion in which they are mixed comprises Polyether Polyol 100 parts with Isocyanate of 65- 80 parts,

c. the pouring is done manually or with help of a machine, d. closing the mould within five seconds after pouring, e. carrying out of the curing for a period of time,

The process of claim 4 wherein:

a. the machine used for pouring chemicals is a high/low pressure polyurethane machine,

b. the curing time is 5-7 minutes.

The damper or seat pad or a grommet for Seat Assembly according to claim 1 wherein the automobile vehicle is a two wheeler or a three wheeler.

The Seat Assembly for an automobile vehicle according to claim 2 wherein the automobile is a two wheeler or a three wheeler.

The process of making a Seat Assembly for an automobile vehicle according to claim 3 wherein the automobile is a two wheeler or a three wheeler.