Title:
Shutter having improved frame composition, and method for manufacture
Kind Code:
A1


Abstract:
A window shutter incorporates a lightweight composite frame that is particularly resistant to temperature and humidity changes. Members forming the frame are laminations of plastic shell members on one or more face surfaces of an elongate wood-based core. This invention is to provide a method for manufacturing a shutter frame stock, and the finished product. The method is to first prepare a body, and a shell member; the body is elongated, and is made of a wood based material. The shell member is made of plastic and glue is used to affix the shell member onto the face surface of the body, in order to form basic frame stock; the basic frame stock is then further processed to form the profile desired, and to generate the required frame stock.



Inventors:
Nien, Keng Hao (Taichung, TW)
King, Gordon (Chandler, AZ, US)
Application Number:
10/702392
Publication Date:
05/19/2005
Filing Date:
11/04/2003
Assignee:
NIEN KENG H.
KING GORDON
Primary Class:
Other Classes:
52/473
International Classes:
E06B7/09; (IPC1-7): E04B1/00
View Patent Images:
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Primary Examiner:
GILBERT, WILLIAM V
Attorney, Agent or Firm:
SHELDON & MAK (9th Floor 225 S. Lake Ave., Pasadena, CA, 91101, US)
Claims:
1. A method for making frame stock for shutter panels, including the steps of: a) preparing an elongate body comprising a material of wood origin and having a face surface; b) preparing an elongated shell member made of a plastic material, the shell member having an overall thickness of not less than 2 mm from a base surface, the base surface being shaped to fit against the face surface; b) affixing the base surface of the shell member onto the face surface of the body to form a workpiece; and c) shaping the workpiece to a desired contour to form the frame stock.

2. The method of claim 1, wherein the affixing is by gluing.

3. The method of claim 1, wherein the plastic material is selected from the group consisting of ABS, PVC, PC, PE, PP, and PS.

4. The method of claim 1, wherein the plastic material comprises a material selected from the group consisting of ABS, PVC, PC, PE, PP, and PS.

5. The method of claim 4, wherein the plastic material further comprises a foaming agent.

6. The method of claim 5, wherein the plastic material further comprises a filler material.

7. The method of claim 6, wherein the filler material comprises diatomaceous earth (DE).

8. The method of claim 6, wherein the plastic material is a first plastic material forming an interior portion of the face shell members, the face shell members further comprising a protective cladding formed of a second plastic material, the protective cladding at least partially surrounding the first plastic material.

9. The method of claim 8, wherein the second plastic material comprises the material selected from the group of claim 4.

10. The method of claim 4, wherein the plastic material is a first plastic material forming an interior portion of the face shell members, the face shell members further comprising a protective cladding formed of a second plastic material, the protective cladding at least partially surrounding the first plastic material.

11. The method of claim 10, wherein the second plastic material comprises the material selected from the group of claim 4.

12. The method of claim 4, wherein the plastic material further comprises a filler material.

13. The method of claim 12, wherein the filler material comprises diatomaceous earth (DE).

14. The method of claim 12, wherein the plastic material is a first plastic material forming an interior portion of the face shell members, the face shell members further comprising a protective cladding formed of a second plastic material, the protective cladding at least partially surrounding the first plastic material.

15. The method of claim 14, wherein the second plastic material comprises the material selected from the group of claim 4.

16. The method of claim 4, wherein the plastic material is a first plastic material forming an interior portion of the face shell members, the face shell members further comprising a protective cladding formed of a second plastic material, the protective cladding at least partially surrounding the first plastic material.

17. The method of claim 16, wherein the second plastic material comprises the material selected from the group of claim 4.

18. The method of claim 1, wherein the thickness of each shell member is not greater than 6 mm.

19. The method of claim 1, wherein the body has first and second face surfaces, the step of preparing of the elongated shell member comprises preparing two shell members, and the step of affixing is of respective base surfaces of the shell members to the first and second face surfaces of the body.

20. The method of claim 1, wherein the body is made of wood.

21. The method of claim 1, wherein the body is made of LVL.

22. The method of claim 1, wherein the body is made of plywood.

23. The method of claim 1, wherein the body is made of OBS.

24. The method of claim 1, wherein the shell members, prior to shaping, are rectangular in cross section.

25. The method of claim 1, wherein the shaping comprises machining at least one of the shell members subsequent to the affixing.

26. The method of claim 1, wherein the shaping comprises molding at least one of the shell members with a non-rectangular cross-section.

27. The method of claim 26, wherein the molding comprises extruding.

28. The method of claim 1, wherein the body also has opposing side faces joining the face surfaces, the method further comprising the steps of preparing two side shell members of a plastic material, each side shell having a base surface, and gluing to affix the base surfaces of the two side shell members onto the two side faces of the body.

29. The method of claim 1, comprising the further step of spreading a protective coating on the workpiece subsequent to at least a portion of the shaping step.

30. A method for making a shutter panel assembly comprising the steps of: a) providing a supply of elongate frame stock members; b) forming a pair of the frame stock member as stiles; c) forming a pair of the frame stock member as respective top and bottom rails, wherein at least one of the stiles and rails is made from a frame stock member manufactured according to the method of claim 1; d) providing a set of louvers; e) positioning the stiles in parallel spaced relation engaging opposite ends of the louvers; and f) rigidly joining the rails, respectively, to opposite ends to the stiles to form the shutter panel assembly.

31. A method for making a shutter assembly includes the steps of: a) providing a mounting frame; b) providing a plurality of hinges; c) making one or more shutter panel assemblies according to claim 29; and d) pivotally connecting the one or more shutter panel assemblies to the mounting frame using the hinges to form the shutter assembly.

32. A frame stock member comprising: an elongate body comprising a wood material and a plurality of shell members affixed and covering respective faces of the elongate body, the shell members each being formed of a plastic material and having an overall thickness of not less than 2 mm.

33. The frame stock member of claim 32, wherein the shell members are affixed with glue.

34. The frame stock member of claim 32, wherein the plastic material is ABS.

35. The frame stock member of claim 32, wherein the plastic material comprises ABS.

36. The frame stock member of claim 35, wherein the plastic material further comprises diatomaceous earth (DE).

37. The frame stock member of claim 32, further comprising an outer coating including a sealer and/or a paint.

38. The frame stock member of claim 29, wherein the outer coating comprises a UV inhibitor.

39. The frame stock member of claim 32, wherein the body is rectangular in cross-section, the faces including front and back elongated surfaces, and two side surfaces, each side surface joining the front and back elongated surfaces of the body, and each of the side surfaces also having a shell member affixed thereon.

40. The frame stock member of claim 32, wherein the body is made of wood.

41. The frame stock member of claim 32, wherein the body is made of LVL.

42. The frame stock member of claim 32, wherein the body is made of plywood.

43. The frame stock member of claim 32, wherein the body is made of OBS.

44. The frame stock member of claim 32, having a generally L-shaped cross-section.

45. The frame stock member of claim 32, having a generally L-shaped cross-section.

46. A shutter panel assembly comprising: a) a pair of stiles formed from the frame stock of claim 31 b) a set of louvers, opposite ends of the louvers engaging respective ones of the stiles; and f) a pair of upper and lower rails rigidly joined to opposite ends to the stiles.

47. A shutter assembly comprising: a) a mounting frame; and b) one or more shutter panel assemblies according to claim 46, each of the shutter panel assemblies being pivotally supported by the mounting frame.

48. A frame stock member comprising: an elongate body comprising a wood material and having opposing face surfaces, and a plurality of shell members affixed and covering respective faces of the elongate body, the shell members each having an overall thickness of not less than 2 mm and comprising a first thermoplastic containing a quantity of diatomaceous earth (DE) having not more than 2% moisture content by weight, wherein: a) the first thermoplastic also contains a foaming agent and the quantity of DE is between 1% and 40%; or b) the first thermoplastic is substantially solid and the quantity of DE is between 1% and 70%.

49. The frame stock member of claim 48, wherein at least one of the shell members further comprises a co-extruded protective cladding of a second thermoplastic, the protective cladding at least partially surrounding the first thermoplastic, the first thermoplastic containing a thermoplastic component of the second thermoplastic.

Description:

BACKGROUND

This invention is related to shutters, and more particularly to shutters having improved frame composition, and methods for manufacturing same.

Typical shutter panels of the prior art include frame members such as those shown in FIG. 1, the panels including a top rail 1, a bottom rail 2, and two stiles, designated 3 and 4. These frame members are either made of machined wood, or simulated wood made of foamed plastics. Unfinished frame members or frame stock are assembled as frame workpieces, and then further processed for obtaining desired profiles, with sockets for receiving louvers, and to create an aesthetical appearance.

However, when foamed plastic is used for forming the frame stock of shutter panels, they are generally made from injection molding to form the necessary frame stock. Since the frame stock members typically have a substantial thickness, the time necessary for cooling in mass production is substantial. Therefore the speed of mass production is limited, and the cost of production is high. Moreover, since often thermal plastics are used (e.g. PVC, PS, PE, or PP), the strength of the frame member is typically not sufficient, and there could easily be temperature affected deformation. Especially when the frame has larger dimensions, the temperature induced deformations increase. Therefore when used for the frame members of shutter panels, there could be warping, with consequent difficulties in the opening and closing of the shutters. Moreover, the warping can be so much as to make the shutter unusable. Additionally, a shutter panel entirely made of plastic, especially solid plastic, can be excessively heavy.

Furthermore, a shutter panel made entirely of plastic is typically affixed to the window frame using hinges that are mounted on the frame stock using screws. The screw holes can become enlarged due to temperature changes, and thereby leading to a reduction in the force holding the screws in place, and gradually cause the loosening of the frame member, and even the entire shutter from the wall.

Wood is a diminishing resource, with prices tending to increase, particularly in that many countries are promoting environmental protection and greening. If the frame stock is made of wood, the relative manufacturing cost of the frame stock correspondingly increases, leading to higher selling prices. Moreover, since frame stock make of wood is easily affected by moisture (the moisture in the wood itself), resulting in warping. This is especially true for frames having larger dimensions, such warping being significantly detrimental. Therefore, warping is a significant problem with shutter panels made of wood, making it difficult to open or close the shutters, or in extreme cases, rendering the shutters unusable.

Thus there is a need for shutters having improved panels that are strong, light in weight, inexpensive to manufacture, and relatively impervious to both temperature and humidity changes.

SUMMARY

The present invention meets this need by providing a shutter that incorporates composite wood and plastic frame members. In one aspect of the invention, a method for manufacturing frame stock for shutters includes the steps of.

    • a) preparing an elongate body comprising a material of wood origin and having a face surface;
    • b) preparing an elongated shell member made of a plastic material, the shell member having a base surface and an overall thickness of not less than 2 mm;
    • b) affixing the base surface of the shell member onto the face surface of the body to form a workpiece; and
    • c) shaping the workpiece to a desired contour to form the frame stock.

The affixing can be by gluing. The plastic material can be or include selected from the group consisting of ABS, PVC, PC, PE, PP, and PS. The plastic material further include a foaming agent and/or a filler material which can include diatomaceous earth (DE).

The plastic material can be a first plastic material forming an interior portion of the face shell members, the face shell members further including (whether or not the first plastic material has a foaming agent) a protective cladding formed of a second plastic material, the protective cladding at least partially surrounding the first plastic material. Preferably the second plastic material includes the material selected above from the group of plastic materials for facilitating adhesion of the cladding to the first plastic material. Preferably the thickness of the shell member is not greater than 6 mm for rapid cooling.

The body can have first and second face surfaces, the preparing of the elongated shell member can be preparing two shell members, and the affixing is of respective base surfaces of the shell members to the first and second face surfaces of the body. The body be made of wood, LVL, plywood, MDF, and/or OBS.

The resulting frame stock, when used on shutter panels or mounting frames therefor, is not easily affected by temperature or moisture changes to cause warping, and the frame members has good strength.

The shell members, prior to shaping, can be rectangular in cross section, and the shaping can include machining at least one of the shell members subsequent to the affixing. The shaping can include molding at least one of the shell members with a non-rectangular cross-section, and the molding can include extruding.

The body can also have opposing side faces joining the face surfaces, the method further including the steps of preparing two side shell members of a plastic material, each side shell having a base surface, and gluing to affix the base surfaces of the two side shell members onto the two side faces of the body.

The method preferably includes the further step of spreading a protective coating on the workpiece after completing at least a portion of the shaping step.

In another aspect of the invention, a method for making a shutter panel assembly includes the steps of:

    • a) providing a supply of elongate frame stock members;
    • b) forming a pair of the frame stock members as stiles;
    • c) forming a pair of the frame stock members as respective top and bottom rails, wherein at least one of the stiles and rails is made from a frame stock member manufactured according to the method of claim 1;
    • d) providing a set of louvers;
    • e) positioning the stiles in parallel spaced relation engaging opposite ends of the louvers; and
    • f) rigidly joining the rails, respectively, to opposite ends to the stiles to form the shutter panel assembly.

Also, a method for making a shutter assembly includes the further steps of providing a mounting frame and a plurality of hinges, and pivotally connecting one or more shutter panel assemblies to the mounting frame using the hinges. The step of providing the mounting frame can include assembling the frame with at least one of the frame stock members manufactured according to the method of claim 1.

In a further aspect of the invention, a frame stock member includes an elongate body including a wood material and having a face surface, and a shell member affixed and covering the face surface, the shell member being formed of a plastic material and having an overall thickness of not less than 2 mm. The plastic material can be or include ABS, and the plastic material can further comprise diatomaceous earth (DE). The frame stock member can further have an outer coating including a sealer and/or a paint, which preferably includes a UV inhibitor, the UV inhibitor preferably protecting the plastic material of the shell members.

The body can have first and second face surfaces, the elongated shell member can be one of two shell members, respective base surfaces of the shell members being affixed to the first and second face surfaces of the body. The body can also have the two side surfaces, each having a shell member glued thereon. The body can be made of wood, LVL, plywood, MDF, and/or OBS. Preferably the thickness of the shell member is not more than 6 mm.

In yet another aspect, the invention provides a shutter panel assembly including a pair of stiles formed from the frame stock of claim 18, a set of louvers, opposite ends of the louvers engaging respective ones of the stiles, and a pair of upper and lower rails rigidly joined to opposite ends to the stiles. Further, one or more of the shutter panel assemblies can be pivotally supported in a mounting frame to form a shutter assembly.*

In another aspect, the invention provides a frame stock member including an elongate body comprising a wood material and having opposing face surfaces, and a plurality of shell members affixed and covering respective faces of the elongate body, the shell members each having an overall thickness of not less than 2 mm and including a first thermoplastic containing a quantity of diatomaceous earth (DE) having not more than 2% moisture content by weight, wherein either the first thermoplastic also contains a foaming agent and the quantity of DE is between 1% and 40%, or the first thermoplastic is substantially solid and the quantity of DE is between 1% and 70%. At least one of the shell members can be co-extruded with a protective cladding of a second thermoplastic that at least partially surrounds the first thermoplastic, the first thermoplastic containing a thermoplastic component of the second thermoplastic for facilitating adhesion of the cladding.

DRAWINGS

These and other features, aspects and advantages of the present invention will become better understood with reference to the following description, appended claims and accompanying drawings where:

FIG. 1 is a perspective view of a prior art shutter panel;

FIG. 2 is a flow chart of the preferred embodiment of the method for manufacturing the frame stock for shutters, of the current invention;

FIG. 3 shows a preferred embodiment of the assembled product using the current invention;

FIG. 4 is a cut away view of the first step of the method of the preferred embodiment of the current invention;

FIG. 5 is a sectional view of the basic frame stock resulting from the second step of the method of the preferred embodiment of the current invention;

FIG. 6 is a sectional view across line 6-6 of FIG. 3;

FIG. 7 is a sectional view along lines 7-7 in FIG. 3;

FIG. 8 is a sectional view of a finished product from another preferred embodiment of the current invention FIGS. 9-12 are sectional views showing respective L-shaped alternative configurations of the basic frame stock of FIG. 5;

FIG. 13 is a sectional outline view showing a finished outline for L-shaped frame stock based on the basic frame stock of FIGS. 9-12;

FIG. 14 is a sectional view showing a further L-shaped alternative configuration of the basic frame stock of FIG. 5; and

FIG. 15 is a sectional view showing a Z-shaped alternative configuration of the basic frame stock of FIG. 5.

DESCRIPTION

The present invention is directed to a window shutter having an improved lightweight frame composition that is particularly resistant to temperature and humidity changes. With reference to FIGS. 2-7 of the drawings, a first exemplary and preferred embodiment of the current invention includes a method 100 (See FIG. 2) for manufacturing the frame stock for shutters, including a blank preparing step 102 for preparing a body 10, a first shell member 20, and second shell member 30 as shown in FIG. 4. The body 10 is preferably of wood origin. As long as a significant portion of the materials of the body 10 are of wood origin, expansion and contraction caused by changes in temperature are limited. Thus the core 10 can include solid wood, layered wood based materials (LVL), plywood, medium density fiberboard (MDF), wafer board (OSB), and other composite wood materials containing wood. The body 10 is cut into a elongated shape, with a cross sectional thickness of about 6 to 14 mm. In the exemplary configuration of FIG. 4, the body 10 has an elongated front surface 11, an elongated back surface 12, and first and second side surfaces 13 and 14.

The two shell members 20 and 30, are preferably made by plastic extrusion. They can be made of solid or foamed plastics such as ABS (acrylonitrile butadiene styrene), PVC (polyvinylchloride), PC (polycarbonate), PE (polyethylene), PP (polypropylene), PS (polystyrene), etc., including so-called “engineering plastics”, with or without fillers, as is well known in the trade. Also, the foamed plastic can have a protective cladding, the interior of the shell members being foamed plastic, preferably with a filler. In this configuration, the cladding and the plastic of the interior are generally preferred to be both of the same plastic in order to promote adhesion of the cladding. For example, the filler can be diatomaceous earth (DE), the plastic being ABS (although DE is believed to be compatible with most thermoplastics). Foamed and un-foamed plastics having DE fillers are described in U.S. Pat. Nos. 6,583,189 and 6,596,784 to King and assigned to the same assignee as the present invention, both patents being incorporated herein in their entirety by this reference. More particularly, the shell members can be formed as an extruded closed cell foam, preferably containing between 1% and 40% DE by weight for added strength, the DE having less than about 2% moisture. Alternatively, the shell members can be a substantially solid plastic containing from 1% to 70% DE. Also, the shell members can be co-extruded, having an interior portion and a protective cladding at least partially surrounding the interior portion for improved surface finish and impact resistance. The cladding can be solid ABS, and the interior can include a combination of ABS and DE, with or without a foaming agent as indicated above. Alternatively, the cladding can be PVC, the interior including PVC and DE.

The shell members 20 and 30 are elongated in shape, and have a cross sectional thickness of about 2 to 6 mm. The plastic material is preferably ABS. In the configuration of FIG. 4, the dimensions of a major face or base surface of each shell is substantially identical to that of the front surface 11, or back surface 12, of body 10. Because the two shell members 20 and 30 have thicknesses of only 2 to 6 mm, the cooling time required in extrusion is very short, and mass production is viable. That helps to increase the production speed for the frame stock 50, described below. Further, the alternative of forming the frame stock entirely of plastic would require very large machines that can handle the correspondingly higher volumes of plastic. Practically, even such larger machines would normally be limited to lower production rates of finished frame stock. It will be understood that only a single shell member (20) can be used, and although the body 10 is shown rectangular, the surfaces 11-14 being planar, other shapes are contemplated. All that is required is that each shell member have a base surface contour that matches the corresponding face surface.

Also in the method 100, the first shell member 20 is affixed onto the front surface 11 and, optionally, the second shell member is affixed to the back surface 12 of the body 10 in an affixing step 104, using glue (preferably) or other adhesive. Suitable adhesives include 3M1099 Plastic Adhesive, from 3M Company of St. Paul, Minn. The resulting product is an elongated basic frame stock or workpiece 40 as shown in FIG. 5. Structurally, this exemplary semi-finished product has: a body 10, having an elongated shape with a rectangular cross section, the material being of wood origin. This body 10 has a elongated front surface 11 and an elongated back surface 12, a first side surface 13 and a second side surface 14, each joining the front surface 11 to the back surface 12. There is also a front or first shell member 20, and a back or second shell member 30. Each of the shell members 20 and 30 is made of plastic such as ABS as described above. At least one (base) surface of each of the shell members is substantially matching that of the front surface 11 or back surface 12 of the body 10. First shell member 20 is glued onto the front surface of body 10; the second shell member 30 is glued onto the back surface 12 of body 10.

Further in the method 100, and as shown in FIGS. 6 and 7, there is further processing in a shaping step 106, by cutting or other method of formation, in order to form holes or cavities 41 that accept axial projections or pins of the louvers (when the workpiece 40 is to be used in a shutter panel as described below) and, optionally, to provide desired cross-sectional and/or edge profiles of the workpiece 40, such as a slot 42 and surface contouring 43′ of one or more of the shell members as indicated in FIG. 7. Thus the workpieces 40 are processed to form semi finished frame members or stock 50 to be used in forming a shutter panel assembly 52 having a set of louvers 54 as shown in FIG. 3. As further shown in FIG. 3, one or more of the shutter panel assemblies 52 are typically pivotally supported by hinges 55 in a mounting frame 56 to form a shutter assembly 58.

Preferably the outer surface of the shell members, or more particularly those portions exposed to normal viewing, have the same material composition as that of the louvers, for promoting a uniform surface appearance of the panel assembly 52. (This same consideration also applies to the mounting frame 56.) Also, it is preferred that the shutter panels be light in weight, for decreased hinge loading and for permitting, with stronger composites, wider shutter panels to be used, permitting shutter assemblies of a given size to be made with fewer panels. For example, one preferred composition of the louvers 54 includes a foam (ABS) plastic core, with ABS cladding. When this composition is used for the louvers, it is preferred that the outer surface of the shell members comprising the stock 50 have the same formulation of the ABS cladding of the louvers. Further, it is also preferred that the shell members of the panel frame stock have foam cores for reduced weight. More generally, whatever the interior composition of the louvers and the shell members, it is preferred that the outer surfaces of both have the same formulation. This is true for the shutter panel assembly 52 as well as for the complete shutter assembly 58, whether or not the product is to receive paint or other coating, the appearance of which is dependent on the base material.

Optionally, there is an additional painting step 108 of applying sealant on exposed wood-origin surfaces subsequent to machining and/or applying a finish coating of paint. These wood-origin surfaces include the ends and any open side surfaces that exist, either because there is no shell, or because the machining of the cavities 41, the slots, 42, etc, as well as the relatively minor exposure of the body 10 that may result from machining through a shell. Suitable sealants include Tuff-Pro sealant, from J&R Industries. Inc. of Wilmington, Calif. A preferred paint is polyurethane (PU) paint. The benefits of the finish coating of paint include hiding smoothed-over imperfections and seam lines between shell members (if present), and savings in providing UV resistant additives to the paint rather than the plastic, Using the above steps, the frame stock 50 of the current invention has the characteristics of both wood and plastic. In other words, the body 10 of frame stock 50 is made of wood, thereby making the frame stock resistant to warping caused by temperature changes. Because the shell members 20 and 30 are ABS (or other plastic being relatively impervious to moisture), the frame stock also does not easily warp as a result of change in moisture, the wood being protected from the elements by the plastic shell members. Even is some of the body 10 is exposed as a result of machining through a shell to obtain a desired contour, normally only a minor surface area is so exposed, the wood remaining significantly protected from moisture. Further, this exposed area can be protected with a suitable sealant as described above. Moreover, the combination of the two types of materials, the plastic being of robust thickness, strengthens the combined structure, making it harder to bend. Therefore, when the frame stock 50 is used for building shutter panels, the shutter panel would not be easily affected by temperature or moisture, or suffer from lack of strength, and cause the warping on the sides of the shutter panel, or other warping problems. Moreover, when a shutter is affixed to the window using hinges, the applicable hinged area is the wood body 10, and therefore the screw holes would not be as easily affected by temperature variations, nor would they be weak as in the case of a thin plastic shell having a low-density foam core. Therefore, the shutters are more resistant to loosening or falling off over time. The life of the shutters therefore could be increased. Moreover, according to actual product analysis, when compared to an all plastic product, the frame stock of the present invention having the wood core and foamed plastic shell members can have 25% less weight. This is because plastic, even foamed plastic having suitable strength, is heavier than wood. Thus whereas the maximum practical width of shutter panels formed only of foamed plastics is between 23 and 24 inches, the shutter panels 52 having shell members of foamed plastic can have a width of 30 inches or more, providing significant labor cost savings for the overall combination of the shutter assembly 58.

Additionally, the two shell members 20 and 30 of frame stock 50, being preferably 2-6 mm thick, are considerably thinner than the full thickness of the frame stock 50. The times required for extrusion and for cooling are short, and therefore mass production is viable, and that helps to improve production capacity for the frame stock 50. Moreover, wood and ABS plastic are easily glued together. Also, ABS plastic is a high molecular polymer, its surface has a good smoothness, and is easy to color, and has good abrasion resistance. Therefore, when it is glued onto the front and back surface 11 and 12 of body 10, this causes frame stock 50 to have a better surface smoothness, color, and abrasion resistance. Also, after gluing, the workpiece 40 is in an elongated rectangular form, and is easy to further process. Both wood and ABS plastics are easily machined and processed. Therefore frame stock 50 can easily be mass produced, to reduce the product price and increase the competitiveness.

With further reference to FIG. 8, an alternative preferred configuration of the present invention includes a finished product being frame stock 60 that is not limited to having shell members on only front and back surfaces 11 and 12 of body 10 as described above. Frame stock 60 has, on its front surface 62, back surface 63, first side surface 64, and second side surface 65 of body 61, and shell members 66. The resulting frame stock 60, when used in the shutter 52, has further improved strength, and it appears to have a unitary appearance when viewed from an angle.

With further reference to FIGS. 9-14, the frame stock members can be generally L-shaped in cross section, being particularly adapted for forming the mounting frame 56. As shown in FIG. 9, an L-shaped frame stock member 70A includes a counterpart of the workpiece 40, with a counterpart of the body, designated 10A affixed thereto, and a counterpart of the second shell member, designated third shell member 30A, bonded to the body 10A opposite the workpiece 40, a workpiece 40A being described thus far in a counterpart of the affixing step 104. In a counterpart of the shaping step 106, a desired outer contour 70S is formed, for example, in the shape shown in FIG. 13, the result being indicated by broken lines in FIG. 9. Similarly, FIG. 10 shows another L-shaped frame stock member, designated 70B having the same exemplary finished shape 70S shown in FIG. 13, but with omission of the third shell member 30A, the member 70B having an enlarged counterpart of the body, designated 100B. Another alternative configuration, shown in FIG. 11 and designated 70C, has a foreshortened counterpart of the second shell member, designated 30B, and a further enlarged counterpart of the body, designated 10C. In yet another alternative configuration 70D shown in FIG. 12, there is a foreshortened counterpart of the body member 10, designated 10D, and a yet further enlarged counterpart of the body 10C, designated 10E. It will be understood that further variations of these configurations are possible.

FIG. 14 shows another L-shaped frame stock member, designated 70E, that includes counterparts of the shell members 66 that are affixed to the first and second side surfaces 64 and 65 of the body 61 of FIG. 8. More particularly, the frame stock member 70E includes an L-shaped counterpart of the body, designated 10F, foreshortened counterparts of the shell members 20, 30A, and 30B, respectively designated 20A, 30C, and 30D, a top shell member 67, a medial shell member 68, and a bottom shell member 69. It will be understood that the body 10F can be formed of plural body portions such as are shown as the bodies 10 and 10C in FIG. 11 and the bodies 10D and 10E in FIG. 12.

With further reference to FIG. 15, the frame stock members can also be generally Z-shaped in cross section. FIG. 15 shows a Z-shaped frame stock member 70F having a Z-shaped counterpart of the body, designated 10G, a widened counterpart of the top shell member, designated 67A, a counterpart of the bottom shell member 69, and pairs of the second shell member 30C, the third shell member 30D, and the medial shell member 68. As in the configurations of FIGS. 9-12 and 14, a desired outer contour 70T is formed In a counterpart of the shaping step 106, the result being indicated by broken lines in FIG. 15.

Although the present invention has been described in considerable detail with reference to certain preferred versions thereof, other versions are possible. For example, one or more of the shell members 20 and 30 (and/or the shell members 66 of FIG. 8) can have a non-rectangular extruded contour, as long as the base surface shape corresponds to the surface of the core 10 to which it is to be bonded. Moreover, the shell members can be affixed by other methods, such as by direct extrusion onto the body 10. Therefore, the spirit and scope of the appended claims should not necessarily be limited to the description of the preferred versions contained herein.