WO1997012732A1

WO1997012732A1 - Utensil handle and method of making same

Info

Publication number: WO1997012732A1
Application number: PCT/US1996/015946
Authority: WO
Inventors: John P. Vanderhoef; Edward St. Yves; Theodore S. Babcock
Original assignee: Kellogg Brush Manufacturing Co.
Priority date: 1995-10-05
Filing date: 1996-10-04
Publication date: 1997-04-10

Abstract

A utensil handle with particular grip characteristics due to using a plurality of resins is provided. Methods for making the utensil handle also are provided.

Description

1JTF.NSIL HANDLE AND METHOD OF MAKING SAME

Abstract of the Disclosure

The utensil handle ofthe present invention is formed in a mold having a cavity shaped in the form of the desired final handle shape. One side ofthe cavity is formed by a core element or slide movable from a first position in which the end ofthe core element defines one surface of the finished handle and a second position in which the core element projects a pre-determined distance into the mold cavity. With the core element in its second position, a structural or rigid resin is injected into the reduced cavity and allowed to at least partially harden. The core element is then withdrawn to its first position and a second resin having a rubbery characteristic is injected in to the space formed by the withdrawal ofthe core element face from the cavity. Accordingly, a unitary utensil handle is formed which provides a body of structural resin with an inset of a rubbery material which provides a pleasing grip and appearance.

Background of the Invention The present invention relates to a utensil handle which has pleasing grip characteristics and also to a method of making that handle.

The handles commonly employed for kitchen, bathroom, and general cleaning utensils are typically formed by injection molding and comprise a single thermoplastic resin material. While some proposals have been made previously for multiple component handles, these handles have typically been assembled from e.g., by adhesive or using interlocking parts, from separately formed elements. The cost associated with separately forming the elements has prevented the widespread adoption of such constructions.

Among the several objects of the present invention may be noted the provision of a utensil handle which provides satisfyingly ergonometric handling characteristics; the provision of such a handle which provides a comfortable grip; the provision of such a handle which provides a plesing appearance; the provision of such a handle which has an essentially unitary construction and does not have to be assembled; the provision of such a handle which employs a structural material for strength but includes a rubbery gripping surface; the provision of a method of making a utensil handle which efficiently produces a pleasing product; the provision of such a method which can be implemented in a cost effective manner; the provision of such a method which is highly reliable and which is relatively simple and inexpensive. Other objects and features will be in part apparent and in part pointed hereinafter. Summarv of he Invention

The utensil handle of the present invention comprises a first elongate portion formed of a structural resin and. set into the first portion, an inset of a rubbery resin providing a pleasing grip surface and. preferably, a contrasting color. The handle is formed in a mold providing an elongate cavity having the dimensions and shape ofthe desired product. One surface ofthe cavity is formed by a core element which is movable from a first position in which the face of the core element defines a portion of the overall surface of the full cavity and a second position in which the core element projects a predetermined distance into the cavity. With the core element in its second or forward position, a structural thermoplastic resin is injected into the reduced cavity thereby to form the first portion of the utensil handle. Once the structural resin has at least partially hardened, the core element is withdrawn to its first position and a resin having a rubbery characteristic is injected into the space formed by the withdrawal of the core element. This second resin bonds with the first so that the finished handle is essentially an integrated structure.

Brief Description of he Drawings Figure 1 is a side view of a handle constructed in accordance with the present invention;

Figure 2 is a sectional view ofthe handle taken essentially along the line 2-2 of Figure 1 ; Figure 3 is a side view with parts broken away of a mold assembly for forming the handle of Figure 1 with a core element of the assembly in a forward position;

Figure 4 is a view similar to Figure 3 with the core element in a withdrawn position; and Figure 5 is a view similar to Figures 3 and 4 showing the injection of a second resin into the mold.

Corresponding reference characters indicate corresponding parts throughout the several views of the drawings.

Description of the Preferred Embodiments Referring now to Figure 1 , the handle illustrated there is elongate and includes a slightly arched gripping portion 1 1 and a socket portion 13 for receiving a utensil such as a brush or sponge head. The major portion of the handle structure is formed of a structural or rigid thermoplastic resin. designated by reference character 17 in Figure 2. However, set in to the back ofthe arched portion 1 1 is what may be termed a grip pad 19 formed of a rubber)' resin and designated by reference character 21 in Figure 2. In accordance with the present invention, the grip pad 19 is intimately bonded with the structural resin portion 17 so that the handle is effectively an integral structure. Referring now to Figure 3. an injection mold assembly is designated generally by reference character 25. As is understood by those skilled in the art, such molds are typically assembled of several elements but, for purposes of illustration, only the portions which are relatively movable during the manufacturing process are described in detail herein. Mold assembly 25 provides an elongate cavity 27 which is generally in the shape desired for the handle of Figure 1.

Set in to the main mold body, designated by reference character 29, is a slide or movable core element 31. The front face of core element 31 has a surface, designated by reference character 33. which defines the exterior surface ofthe grip pad 19 ofthe completed handle. However, in Figure 3. the core element has been moved forward so that the face 33 projects into the cavity 27 a predetermined distance e.g., 3/32 of an inch. Die assembly 25 also includes a second core element 35 which permits forming of the socket portion 13. This core element however, does not move during the actual injection processes as does the core element 31. With the core element 31 in its forward position, a rigid or structural resin such as polypropylene is injected into the cavity 27 so as to fill the reduced cavity 27. Polystyrene or polyethylene might also be used.

Once the structural resin, designated by reference character 34 in Fig. 4. has at least partially hardened, the core element 31 is withdrawn to a position where its front face 33 corresponds with the final desired surface ofthe grip pad 19. Movement ofthe core element 31 is controlled by a wedge element 41 which is in turn moved by an air cylinder 43 or other mechanical means. The core element 31 is biased by springs (not shown) towards its retracted position so that, when the wedge member 41 is lowered, as shown in Fig. 4 , the core element will withdraw the face 33 from the cavity.

With the core element 31 in its withdrawn position, a rubbery resin 46 is injected through a gate 47 to fill the space created by the withdrawal of he core element. The second resin is preferably a rubbery thermoplastic elastomer (TPE) resin such as that sold by Monsanto under the tradename Santoprene or that sold by Shell under the tradename Kraton. After the second resin has sufficiently hardened, the mold is opened, (along part lines not shown) and the completed piece is removed. Since the second resin is injected immediately after forming of the structural resin 34, the two resins bond together intimately so that the final handle assembly is essentially an integral structure though it comprises both the hard structural resin and a rubber.' resin providing a pleasing grip surface. The appearance can be further enhanced by employing resins of contrasting colors, e.g. white for the structural resin and blue for the rubbery resin.

In view ofthe foregoing it may be seen that several objects ofthe present invention are achieved and other advantageous results have been attained.

As various changes could be made in the above constructions without departing from the scope ofthe invention, it should be understood that all matter contained in the above description or shown in the accompanying drawings shall be inteφreted as illustrative and not in a limiting sense.

Claims

CLAIMSWhat is claimed is:

1. The method of making an elongate handle for a utensil which comprises: providing a mold which defines an elongate cavity having a shape which corresponds to the desired shape of the handle, said mold including a core element having a surface facing into said cavity, said core element being movable between a first position in which said surface defines a portion of said cavity and a second position in which said core element intrudes a predetermined distance into said cavity; with said core element in said second position, injecting into said cavity a first resin which forms a structural material; withdrawing said core element to said first position; and injecting into said cavity a second resin which forms a rubbery material thereby to provide a gripping surface on the handle formed in said mold.

2. The method as set forth in claim 1 wherein said first resin is selected from the group polypropylene, polystyrene and polyethylene.

3. The method as set forth in claim 1 wherein said first resin is polypropylene and said second resin is a thermoplastic elastomer.

4. The method as set forth in claim 1 wherein said cavity defines a handle shape providing an arched gripping portion and, at one end ofthe gripping portion, a means for attaching a utensil.

5. The method of making an elongate handle for a utensil which comprises: providing a mold which defines an elongate cavity having an arched shape which corresponds to the desired shape ofthe handle, said mold including a core element having a surface facing into said cavity, said surface defining a portion of said cavity corresponding to the back ofthe arched shape ofthe handle to be formed when said core element is in a first position, said core element being movable between said first position and a second position in which said core element intrudes a predetermined distance into said cavity reducing its volume; with said core element in said second position, injecting into said cavity a first thermoplastic resin which forms a rigid structural material; withdrawing said core element to said first position; and injecting into said cavity a second thermoplastic resin which forms a rubbery material thereby to provide an improved gripping surface on the back ofthe handle formed in said mold.

6. An injection molded utensil handle comprising: a first portion formed of a rigid structural thermoplastic resin and, set into a recess in said first portion, a pad formed of a rubbery thermoplastic elastomer intimately bonded to said structural resin. said pad having matching inner and outer surfaces defined by the same mold surface.

7. A utensil handle as set forth in claim 6 wherein said first resin is polypropylene.