GB2347641A

GB2347641A - Method of making a handle

Info

Publication number: GB2347641A
Application number: GB9905586A
Authority: GB
Inventors: Roger Michael Messenger
Original assignee: HEMO Ltd
Current assignee: HEMO Ltd
Priority date: 1999-03-12
Filing date: 1999-03-12
Publication date: 2000-09-13
Also published as: GB9905586D0; AU2933400A; WO2000054642A1

Abstract

A method of making a handle (12) including a metal component (14) which in use is attached to an article (10) (figure 1 (not shown)), and a body (20) made of thermosetting plastics material moulded in a mould by introducing thermosetting moulding material into the mould in a molten state, a part (18) of the metal component (14) being received within an opening (21) of the plastics body (20) and being retained therein by the interengagement of a gripping formation (24) of the metal component part (18) and the plastics material characterised in that a core (25) including a step formation (26) is provided in the mould and the plastics material is moulded about the core, and the method includes removing the core from the plastics material prior to the plastics material setting, and when the plastics material has set, introducing into the opening the part (18) of the metal component (14).

Description

Title: Method of Making a Handle Description of Invention 4 This invention relates to a method of making a handle for attachment to an article and more particularly but not exclusively to a method of making a handle for attachment to a bowl of a saucepan or the like item of cookware, so that the item may be lifted and handled.

It is known for a handle to be attached to a bowl of an item of cookware using a hidden metal insert which is fixed in the handle, and which engages with a metal part of the item of cookware which projects outwardly from the bowl of the item. The insert typically has formations which dig into the projecting part whereby the handle is securely attached to the bowl. The handle may be made at least predominantly from a plastics material and the insert may be located in the plastics either during moulding, or subsequent to moulding.

By the nature of such an arrangement, the handle which typically is made of a plastics material, requires a guard to prevent the handle material being subjected to flames during cooking, because the handle extends right up to the bowl of the cookware item.

Other arrangements are known which do not require flame guards.

Typically these comprise a handle having a plastic body and a metal component which is adapted to be affixed to the bowl of the item of cookware and upon which any flames would impinge. In known arrangements it is necessary for such a handle to be produced by inserting into a mould, the metal handle component and then to mould the plastics part around a part of the component. This has been thought essential so that the plastics material can be moulded about gripping formations of the metal component so that there is an adequate resistance to withdrawal of the metal component in the resultant handle.

Such a technique for producing handles is however labour intensive, in that substantial manual finishing of the handle is usually required, for example, to remove excess plastics from the metal component, and to finish the metal component which may typically be chrome plated to give a good appearance.

According to one aspect of the invention we provide a method of making a handle including a metal component which in use is attached to an article, and a body made of thermosetting plastics material moulded in a mould by introducing thermosetting moulding material into the mould in a molten state, a part of the metal component being received within an opening of the plastics body and being retained therein by the interengagement of a gripping formation of the metal component part and the plastics material characterised in that a core including a step formation is provided in the mould and the plastics material is moulded about the core, and the method includes removing the core from the plastics material prior to the plastics material setting, and when the plastics material has set, introducing into the opening the part of the metal component.

It has been found that provided the core is removed from the plastics material prior to the plastics material setting, due to shrinkage of the plastics material during setting, an opening may be provided which includes a step which, once the metal component part is introduced into the opening, may interengage with a corresponding gripping formation of the metal componenf part, to provide substantial resistance to withdrawal of the metal component part from the plastics material.

Thus a handle may be made in which no or substantially no finishing of the metal component is required subsequent to moulding, resulting in a substantially improved method at least from an economic point of view.

Because the part of the metal component is introduced into the plastic body subsequent to moulding, either the part of the metal component has to be slightly smaller that the equivalent part of a metal component which is moulded into the plastic material during moulding for the same size opening, or else the opening in the plastics body needs to be slightly larger than the equivalent opening where a metal component is to be moulded into the plastics body for the same size metal component part to be used, to provide sufficient clearance for the metal component part to be introduced.

Preferably the core is removed from the plastics material at the same time that the plastic body is removed from the mould or upon mould opening, although if desired, the core may be removed from the plastics material in the mould prior to the plastics body being removed from the mould. This may be necessary to prevent the plastic body deforming if removed from the mould before the plastic material has adequately set, but where it is necessary to remove the mould former while the surrounding plastics material is still sufficiently hot.

The metal component part may be introduced into the opening while the plastics body is in the mould, but preferably the plastics material is permitted substantially fully to set before the metal component part is introduced, for which purpose the plastics body would most likely require removal from the mould.

To introduce the metal component part, a substantial force may be required generally axially of the handle, so that the gripping formation of the metal component part may be urged past the step in the plastics material formed by the step formation of the mould former.

Preferably though, the part of the metal component which is introduced into the formed opening in the plastics body, is shaped to facilitate introduction.

The metal component preferably includes a part which projects from the plastics body part and has a bracket formation whereby the metal component may be attached to the article.

According to a second aspect of the invention we provide a handle made by the method of the first aspect of the invention.

According to a third aspect of the invention we provide an item of cookware having a handle according to the second aspect of the invention.

The invention will now be described with reference to the accompanying drawings in which: FIGURE 1 is an illustrative perspective view of an item of cookware having a handle made by the method of the invention ; FIGURE 2 is a side view of a metal component of the handle shown in figure 1; FIGURE 3 is a side view of part of a mould former for use in the method of the invention.

Referring to the drawings there is shown an item of cookware 10 being in this example a frying pan having a bowl 11 in which food is contained for cooking, and a handle 12 by which the pan 10 may be lifted and handled.

The handle 12 has a metal component 14 including a bracket part 15 which is formed so as to lie adjacent an exterior surface of the bowl 11, the bracket part 15 having a pair of openings 16 through which fasteners such as rivets 17 or bolts or the like may extend, to attach the handle 12 to the bowl 11.

The metal component 14 further includes a part 18 which is received within a plastics body 20 of the handle 12, in an opening 2 ! therein, the part 18 which is received in the opening 21 having a gripping formation 24 provided by a step, there being a ramp 23 up to the step 24 for a purpose hereinafter explained.

The plastics body 20 is made of a thermosetting plastics material such as for examples only, phenolic resin, melamine or the like, and is made by moulding in a mould.

It is known to provide in a thermosetting plastics handle body 20, an opening 21. However conventionally either the opening 21 houses a metal insert which engages with a metal lug attached to the pan bowl 11, or the opening houses part of a metal component, like metal component 14, but which component is positioned in the mould as molten thermosetting material is introduced into the mould, and thus becomes embedded in the thermosetting plastics as the plastic sets.

In accordance with the invention though, the opening 21 is made during moulding, using a core 25 typically of metal. The core 25 is positioned in the mould during introduction of the thermosetting material but is removed from the opening 21 prior to the thermosetting material fully hardening. Moreover, the core 25 is provided with a step formation 26, and in the resultant plastics body 20, there is produced a corresponding step formation 28 which upon the introduction of the part 18 of the metal component 14, may co-operate with the gripping formation i. e. step 24 of the metal component 14 when the core 25 is removed from the opening 21. The moulding material, where phenolic resin, may be at a temperature of between 150 and 170 c.

It has been found that the step formation 28 in the plastics body 20 may be formed using a core 25 with a step formation 26 due to the innate shrinkage of the plastics material which occurs as the thermosetting material sets. Thus even though upon withdrawal of the core 25, the thermo setting plastics would need to deform to allow the step formation 26 of the core 25 to pass out of the opening 21, as the plastic cools, it has been found that the step formation 28 of the plastics body 20 reconstitutes itself as the plastic shrinks, so that in the resulting plastics body 20, there is formed a step formation 28.

Of course the thermosetting plastics needs to set to some degree in order that the core 25 may be withdrawn whilst the configuration of the opening 21 is retained, but the core 25 must be withdrawn before the plastic is too hard to permit of withdrawal, and before the plastic is too cool so that subsequent shrinkage is too little for an adequate step formation 28 to be reconstituted.

If the core is extracted too early i. e. when the plastic is too hot, thick sections of the plastic at least, will be undercured to the point where voiding and distortion will occur, due to internal gas/moisture pressurising the outer layers of the moulding effectively expanding and voiding the inner sections.

By careful choice of the cure time until the core 25 is removed from the opening 31, this phenomenon is avoided, and although the inside parts of the opening 31 are still supple, the outer cured layers are strong enough to withstand the internal pressure. Final curing of the plastic may continue to take place outside the mould until in a completely solid and rigid state at room temperature.

When the plastic material of the body 20 has further cooled and set, the part 18 of the metal component 14 is introduced into the opening 21. Although materials such as phenolic resin and melamine are not known to be readily flexible, (which quality makes them ideal for use as a handle), it has been found that by applying a sufficient axial force between the metal component 14 and the plastics body 20, the part 18 of the metal component 14 may be introduced into the opening 21 sufficiently far that the step 24 of the metal part 18 can engage behind the step formation 28 of the plastics body 20 and provide a substantial resistance to withdrawal forces. No or virtually no subsequent finishing of the metal component 14 is then required.

It will be appreciated that the ramp 23 of the metal component 14 provided adjacent the step 24 will assist the introduction of the part 18 of the metal component 14 into the opening 21.

Further features of the invention are as follows.

It can be seen that the part 18 of the metal component 14 which is introduced into the opening 21 is joggled so that when introduced into the opening 21 of the plastic body 20, parts of the upper as seen in the drawings at 30 and lower as seen in the drawings at 31, surfaces of the metal part 18 cooperate with corresponding internal surfaces of the opening 21. The metal component part 18 has, in a surface opposite to that upon which the step 26 is provided, a recess 33, and in the opening 21 there is a corresponding formation 35 which is received in the recess 33 of the metal component part 18. The formation 35 of the opening 21 is provided during moulding by the core 25 having a corresponding forming part 38.

The core 25 may be removed from the part-set plastic body 20 in the mould e. g. upon mould opening, or the core 25 may be removed as the body 20 is removed from the mould. The part 18 of the metal component 14 is preferably introduced into the plastic body 20 subsequent to removal of the body 20 from the mould.

Although the invention has been described in relation to a handle 12 in which the plastic body 20 is made in phenolic resin or melamine, the invention may be applied for other thermosetting plastic kinds. Although the invention has been described in relation to a handle 12 for an item of cookware 10, the invention may be more universally applied wherever it is desired to attach a handle to an article. Thus the article 10 may be for example only, a lid of an item of cookware, in which case the handle 12 may be a knob.

The features disclosed in the foregoing description, or the following claims, or the accompanying drawings, expressed in their specific forms or in terms of a means for performing the disclosed function, or a method or process for attaining the disclosed result, as appropriate, may, separately, or in any combination of such features, be utilised for realising the invention in diverse formsthereof.

Claims

CLAIMS 1. A method of making a handle including a metal component which in use is attached to an article, and a body made of thermosetting plastics material moulded in a mould by introducing thermosetting moulding material into the mould in a molten state, a part of the metal component being received within an opening of the plastics body and being retained therein by the interengagement of a gripping formation of the metal component part and the plastics material characterised in that a core including a step formation is provided in the mould and the plastics material is moulded about the core, and the method includes removing the core from the plastics material prior to the plastics material setting, and when the plastics material has set, introducing into the opening the part of the metal component.
2. A method according to claim 1 characterised in that the core is removed from the plastics material at the same time that the plastic body is removed from the mould or upon mould opening.
3. A method according to claim 1 characterised in that the core is removed from the plastics material in the mould prior to the plastics body being removed from the mould.
4. A method according to claim 3 characterised in that the metal' component part is introduced into the opening while the plastics body is in the mould.
5. A method according to any one of the preceding claims characterised in that the plastics material is permitted substantially fully to set before the metal component part is introduced.
6. A method according to any one of the preceding claims characterised in that to introduce the metal component part, a substantial force is provided generally axially of the handle, so that the gripping formation of the metal component part may be urged past the step in the plastics material formed by the step formation of the mould former.
7. A method according to claim 6 characterised in that the part of the metal component which is introduced into the formed opening in the plastics body, is shaped to facilitate introduction into the opening.
8. A method according to any one of the preceding claims characterised in that the metal component includes a part which projects from the plastics body part of the finished handle and has a bracket formation whereby the metal component may be attached to the article.
9. A method of making a handle substantially as hereinbefore described with reference to the accompanying drawings.
10. A handle made by the method of any one of the preceding claims.
11. A handle substantially as hereinbefore described with reference to and as shown in the accompanying drawings.
12. An item of cookware having a handle according to claim 10 or claim 11.
13. Any novel feature or novel combination of features described herein and/or as shown in the accompanying drawings.