IE56978B1

IE56978B1 - A method for forming a lamp base

Info

Publication number: IE56978B1
Application number: IE20186A
Authority: IE
Original assignee: Hackett James W; Hackett Joseph P; Hackett Dominic A
Priority date: 1986-04-23
Filing date: 1986-04-23
Publication date: 1992-02-26
Also published as: GB8709425D0; GB2189426A; IE860201L; GB2189426B

Abstract

The method comprises the steps of forming a main body member of the article of ceramics material; surrounding the member with an outer shell. The exemplified product is a lamp base (1) comprising a main body member (2) cast of potters fine casting clay surrounded by a thin shell (4) of PVC material having side walls (5) extending between end caps (6) and (7). A bore (12) formed in the body member (2) during casting accommodates a cable to a bulb holder (14). To form the lamp base the main body member is cast and dried at room temperature. The outer shell is formed and slid and bonded onto the main body member. A hole (17) is drilled into the bore and the fittings, including the cable are then mounted on the lamp base. Alternatively, the main body member may be cast within the outer shell.

Description

The present invention relates to a method for forming a lamp base, and in pariicular, though not limited lo a method Tor forming a lamp base lor a table lamp or the like. The invention also relates to a lamp base formed according to the method.

In many cases, it is desirable to form a lamp base or indeed any other article from a ceramics material.

The normal process for forming a lamp base or other such article from a ceramics materials is that the 1(1 article is first moulded from the ceramics material which may be any suitable casting clay, such as, for example, potters fine casting plaster, or the like in a mould. On setting, the moulded article is removed from the mould and placed in a kiln for firing and drying. This process can take a number of hours, in most cases. The article is then glazed, or should it be desired to provide a coloured article, the article would normally be painted first, and then glazed. However, after glazing, it is essential to place the article in a kiln again for further firing, drying and baking of the glazed material. This, it will be appreciated, has many disadvantages. First of all, considerable costs are involved in kiln-drying the moulded article in the first instance, and then baking on the glaze thereat'fcr. Fur thermo re, the capital cost of insulation of suitable kiln equipment can be relatively expensive. A further problem with casting articles and indeed lamp bases is that unless one is particularly careful when removing the mould, very often portions of the moulded article may break off during mould removal. This, in general, leads to the scrapping of the article.

There is therefore a need for a method for forming a lamp base of nerur.ii<·?; inuleriul, which avoids problems of methods known heretofore. There is also a need for a lump base made according to the method.

The present invention is directed towards providing such a method and article.

According to the invention, there is provided a method for forming a lamp base, the method comprising the steps of forming a main body member of the lamp base of ceramics material, allowing the main body member to at least partly cure, and mounting an outer shell around the main body member. Preferably, the main body member is moulded in a mould and allowed lo set in the mould.

Additionally, the invention provides a method for forming a lamp base, the method comprising the steps of forming a main body member of ceramics material, forming part of an outer shell in tho form of a sleeve like member, and sliding and securing the sleeve-like member onto the main body member. Preferably, the ir main body member is provided by an elongated body member, and a bore is cast longitudinally therethrough. Advantageously, a pair of end caps are secured to the ends of the main body member and to the ends of the sleeve-like member.

The invention also provides a method for forming a lamp base, comprising the steps of forming an outer shell of the lamp base by forming a sheet of material to form a side wall of an elongated outer shell of the lamp base, forming at least one end cap of the outer shell, securing the end cap to the side wall, placing the outer shell in a support mould with an open mouth facing upwardly, inserting a removable plug to form a hollow core in the outer shell, forming a main body member hy moulding a ceramics material in the outer shell, allowing the ceramics material to set, removing the plug, removing the outer shell from the support mould, and forming a hole through the outer shell to communicate with the bore.

Preferably, a pair of end caps of the outer shell are formed, the second end cap being secured to the side wall t.o close the open mouth after the ceramics material has st?t and the plug has been removed.

Further, the invention provides a lamp base formed $ according to the method of the invention, the lamp s base comprising an outer shell surrounding a main body t member formed of ceramics material.

In one embodiment of the invention, the lamp base 10 comprises an elongated main body member with a bore to accommodate a cable extending longitudinally therethrough. Advantageously, the outer shell is of sheet material, preferably of PVC sheet material.

The invention will be more clearly understood from the 15 following description of embodiments thereof, given by way of example only, with reference to the accompanying drawings, in which: Fig. 1 is a perspective view of a lamp bast' according to the invention, in Fig. 2 is a sectional perspective view of the lamp base of Fig. 1, Fig. 3 is a plan view of portion of the lamp base of Fig. 1 developed.

Fig. Λ is an exploded view of portion of the lamp base of Fig. 1, Fig. 5 is a perspective view of portion of the 0 lamp base of Fig. 1 being assembled, * Fig. 6 is a perspective view of portion of the lamp base of Fig. 1 further being assembled, Fig. 7 is a perspective view of portion of a mould for moulding part of the lamp base of Fig. 1, Fig. H is a perspective view of a lamp base according to another embodiment of the i nven tion, Fig. 9 is a perspective view of a lamp base according to a still further embodiment of lhe invention, Fig. 10 is a perspective view of portion of the c, lamp base of Fig. 9, IS Fig. 11 is a perspective view of a mould for use in the lamp base of Fig. 9, Fig. 12 is a sectional perspective view of the lamp base of Fig. 9 in a further stage of construction, and Fig. 13 is a sectional perspective view ol' the 5 lamp base of Fig. 9.

* Referring to the drawings and initially to Figs. 1 to ΐ there is illustrated a lamp base according to the invention, indicated generally by the reference numeral 1 formed by a method also according to the invention. The method for forming the lamp base 1 is described below. The Lamp base 1 comprises a main body member 2 surrounded by a relatively thin walled outer shell 4 having lour side walls 5 of concave shape, which terminate in a top end cap 6 and a bottom end cap 7. The side walls 5 are of PVC material and formed from a blank 8 provided by a sheet of PVC material as illustrated in Fig. 3 and described below.

The end caps 6 and 7 are also of PVC material. The body member 2 is of ceramics material, in this case potters fine casting plaster and is moulded with a bore 12 extending between the end caps 6 and 7 to accommodate a cable 13. A bulb holder 14 is secured β to the lamp base 1 by a threaded nipple 15 which extends through a portion 32 of the bore 12 of reduced diameter and through a hole 16 in the top end cap 6.

A spacer 33 is provided on the nipple 15 between the bulb holder 14 and the end cap 16. The nipple 15 engages threads (not shown) on the bulb holder 14 and a nut 35 secures the nipple 15 within the? bore 12. A hole 17 through the side wall 5 and the main body member 2 accommodates the cable 13 into ..the bore 12.

A grommet 19 is provided on the outer end of the hole and a safety grommet 36 is provided on the cable 13 to avoid the cable being pulled through the hole 17. $ The lamp base is constructed according to the following method. The body member 2 is cast in a silicone rubber mould. Such moulds will be well known to those skilled in the art and the mould is not described or illustrated. Prior to casting Lhc? body member, a removable plug 29, see Fig. 7, is placed cent rally in the mould (not shown) to form lhe central bores 12 and 32. The plug 29 is of timber and has an elongated portion 30 to form the bore 12 and a short portion 31 of reduced cross sectional area to form the bore 32. The portion 30 is tapered very slightly towards the portion 31 for ease of removal of the plug and the portion 31 is also provided with a very slight taper in the same direction. Potters fine casting plaster is then mixed with water and poured into the * mould and allowed to set. Once set, the removable plug is removed from the cast body member 2 and the e body member 2 is then removed from the rubber mould and allowed to dry at room temperature. As can be seen, the outer surface 3 of the main body member 2 is shaped with concave side walls to form the concave side walls 5 of the outer shell 4. The outer surface of the» mould is then sealed with size.

The outer shell 4 is formed by cutting out the blank 8 illustrated in Fig. 3 to form a sheet of PVC material. Simultaneously with cutting out the blank 8, fold lines 18 which are formed by lines of weakness are impressed into the blank 8 in a suitable pressing tool. Thi? fold lines 18 are illustrated by broken lines. The blank 8 is then bent along the fold lines to form t.he four side walls 5 and a securing fab . The fab 20 is secured to the edge 21 of the side wall 5 by adhesive, in this case an adhesive sold under the Trade Mark SUPERG1.UE” to form a sleeve-like member 38, see Figs. 4 and 5. The outer surface 3 of the body member 2 is coated with an adhesive, in this case a water based glue sold under the Trade Mark POI.YBONF) and the sleeve-like member 38 is slid onto and thus bonded to the body member 2, as illustrated in Fig. 5.

The top end of the body member is coated with PUi.YfiiW and placed upside down on top of a sheet 39 of PVC material as illustrated in Fig. 6. Λ bead 41 of SUPERGLUF. from a dispenser 43 is provided on the PVC sheet 39 around the sleeve-like member 38 to bond the sheet of material 39 to the sleeve-like member 38.

The sheet 39 is then trimmed to form the end cap 6.

Tl» The hole 17 is drilled through one side wall 5 through the body member 2 into the bore 12 to accommodate the electrical cable 13. The cable 13 is threaded through the holes 17 and the grommet 19 is secured at the outer end of the hole 17. The safety grommet 36 is secured on the cable. The portion of the cable within the bore 17 is threaded through the nipple 15 and connected to the bulb holder 14, which in turn is secured to the nipple 15. The bottom end of the cap 7 is formed from a sheet of PVC material similar to the sheet 39 and secured to the bottom end of the lamp base in similar fashion as the top end cap 6.

Referring now to Pig. 8 there is illustrated a lamp base 40 according to another embodiment of the invention. In this case the lamp base 40 is substantially to the lamp base 1 and similar components are identified by the same reference numeral. This lamp base 40 is also construe (.ed using a similar method. The only difference between this lamp base 40 and the lamp base 1 is that two lengths of beading 42 of plastics material are secured to the side walls 5 adjacent the end caps 6 and 7 to conceal the free edges of the end caps 6 and 7.

Referring now to Figs. 9 to 13 there is illustrated a lamp base 50 according to another embodiment of the invention. This lamp base is also substantially similar to the lamp base 1 and similar components are identified by the same reference numerals. The main difference between this lamp base and the lamp base 1 is in the method of construction. In this case, the outer shell comprising the sleeve-like member 38 and the top end cap 6 are formed initially and the main body member 2 is cast directly into the outer shell 4 The sleeve-like portion 38 of the outer shell 4 is formed from a blank similar l.o the blank 8 of Fig. 3.

The end caps 6 and 7 are formed by a vacuum forming process which will be well known to those skilled in the art, and each comprise a base 9 with side walls . The top end cap 6 is secured to the sleeve-like member 38 by bonding the side members 10 to the side walls 5 with SUPERGI.UE. Thus, the outer shell 4 is formed wiLh an open mouth 24, see Fig. 10. The shell is inverted and placed in a support mould 26 with the open mouth 24 facing upwardly. The support mould 26 is of timber material having a hollow interior 27 which defines the outer surface of the shell 4. The plug 29 is placed centrally in the outer shell 4 and illustrated in Fig. 12.

* Once the top end cap 6 is secured to the side walls 5 the side members 10 of the end cap 6 retain the side walls 5 with a substantially concave shape as illustrated in Fig. 5. On insertion into the interior 27 of the mould 26, the side walls 5 of the outer shell 4 are supported and the concave shape of the side walls 5 is retained. Furthermore, the support mould 26 prevents the side walls 5 distorting while the main body member 2 is in fluid form.

The potters fine casting plaster is mixed with water in conventional fashion, and poured into the hollow shell -1, (bus filling the shell to the open mouth 24.

The plaster 11 is allowed to set. The releasable plug is removed and the outer shell 4 with the main body member 2 cast within is removed from the support mould 26.

The hole 17 is drilled through one of the side? walls 5 through the body member 2 into the bore 12. The rest of the assembly of the lamp base 50 is similar to the assembly dcsei’ibed wilh reference to Figs. I to 7.

It has been found that the invention has many advantages over known methods for forming lamp bases from a mouldable ceramics material. Λ particular advantage is that it leads to a relatively β easily manufactured lamp base which can he produced at a relatively low cost. In particular, it has the great advantage that complex shapes may be cast, without any of the difficulties of casting such shapes using known methods of casting. For example, one particular problem with forming lamp bases of complex shape from casting is the difficulty in removing the moulded lamp base from the mould after the article has been cast without damage occuring. In the case of the present invention, this problem does not arise since the surface of the lamp base is formed by the outer shell. Indeed, in the case of the lamp base 50 the outer shell as well as forming the outer surface also forms the mould. Thus, a better quality finish on the outer surface of the lamp base can he provided. Very often, when removing a moulded lamp Ixise from its mould, portions of the mouldable material break off, while in the case of the lamp base 50 this problem does not arise. In the case of the lamp bases 1 and 40 even if small chips break off the body member they will be concealed by the outer shel I .By using flic method of the invention for producing a lamp base, particular advantages are achieved in that relatively lightweight materials which are attractive and pleasing to the eye may be used in the outer shell, and at the same time, the lamp base is provided with a suitable weight to ensure stability of the base, thus avoiding it toppling over.

Furthermore, hy virtue of the fact, that the outer shell can be relatively thin, materials which are relatively expensive may be used in forming the outer shell, since only a relatively thin film of the material is required.

A further advantage and a particularly important advantage of the invention is that by virtue of the fact that the main body member is of ceramics material and is surrounded by an outer shell, il is unnecessary to fire the body member in a kiln. Once it is allowed to dry at room temperature, this is perfectly adequate. In fact, it has been found, in practice, that perfectly adequate drying can be achieved at room temperature in about five days.

While particular shapes of lamp base have been described, it will be appreciated that lamp bases of many other shapes, construction and/or configurations could be manufactured using the methods of the invention without departing from the scope of the invention. further, i I. is envisaged in certain cases (hat an outer· shell with an open mouth could be formed in one piece, and an end cap provided to close the open mouth. Alternatively, in certain cases, it is envisaged that an entirely closed shell could be provided in one piece, in this case the ceramics material could be injected into the shell through a small diameter opening, indeed, a hypodermic needle and syringe and the like could be used for injecting the ceramics material into the shell. In other cases it is envisaged that the shell may be formed in two ba Ives.

Needless to say, it will be appreciated that, materials other than PVC may be used for forming the outer shell, for example, an outer shell of any type of plastic material could be used without departing from the scope of the invention, and indeed, in certain cases it is envisaged that the outer shell may be provided by material other than plastics material. Further, in certain cases, it is envisaged that the outer shell may be provided by a moulding, such as an injection moulded shell, an extruded shell, a rotationally moulded shell or could be formed by any other suitable means. Indeed, in certain cases, it. is envisaged that the outer shell may be of a light timber material, cardboard material or the like.

It is also envisaged that ceramics materials besides potters fine casting plaster may be used. Indeed, it is envisaged that any type of casting clay may be used, such as earthenware, stoneware and the like. Of course, it. will be appreciated that it. is not. necessary for a bore to be provided in the lamp base, and where a bore is provided, it need not be provided through the body member, in certain eases it could be provided through the body member and the outer shell.

II, is also envisaged in certain cases that instead of vacuum forming the end caps or indeed forming I hem in one piece with the shell, they could be formed or manufactured using any other suitable process. ln fact, in certain cases it is envisaged that the top and bottom end caps may be dispensed with altogether. In particular, the bottom end cap in certain cases could be dispensed with. Additionally, it is envisaged that the top and bottom end caps could be of material different to the material forming the side walls, or in certain eases, it is envisaged that the end caps may be of different colour material to the material forming the side walls, and indeed, in certain cases, it is envisaged that both end caps may be of different colours and they may also be of different colour to the material forming the side walls. Similar comments apply to the material of the end caps.

Needless to say, it will be appreciated that while relatively simple shapes with relatively simple cross sections have been illustrated, lamp bast's with iniieh mor<» complex shapes and cross sections could he provided. Indeed, where Ifie shell ο I' tho lamp base is moulded from a material, then extremely complex shapes could be achieved. For cxamph», figures of people, animals or any other types of figures could be moulded of a relatively Iight5 weight shell which would, in general, have a 4 relatively thin wall and the shell would then be filled with the mouldable material. Thus, the shells, fi by virtue of the fact that they could of relatively thin wall construction, could be formed of relatively 10 expensive and exotic materials. This would then give the impression of the lamp base being solidly formed from the material of the outer shell. Needless to say, it is not necessary that the outer shell should be of thin wall construction, it could be of a relatively thick wall construction.

Claims

I. Λ method for forming a lamp base, the melhori comprising the following steps: forming a main body member of the lamp base of
2. Λ method as claimed in Claim 1 in which the main body member is moulded in a mould and allowed to set i n the mould .
3. , A method as claimed in Claim 2 in which the main body member is removed from the mould and allowed to
4. Λ method as claimed in Claims 2 or 3 in which the main body member is an elongated body member and a bore extending longitudinally through the main body member is formed during moulding.
5. Main body member is of potters fine casting plaster. 5 forming part of an outer shell in the form of a sleeve like member, and sliding and securing the sleeve-tike member onto the main body member. 5 cut to size, and spaced apart fold lines being provided in the material corresponding to the corners of the side walls. 5 ceramics material, allowing the main body member to at least partly cure, and mounting an outer shell around the main body member. 10
6. Λ method as claimed in Claim 5 in which the method includes the step of forming the sleeve portion of the outer shell by forming the sleeve with four side walls from a sheet of material, the sheet of material being
7. A method as claimed in Claim 6 in which the method
8. A method as claimed in Claim 7 in which a second end cap is bonded to the other end of the body member and to the ends of the side walls.
9. 9. Λ method as t :1aimed i in any preceding claim i n wh i ch the method i in· 1 udei s the slop of forming the outer she 11 with an open mouth. 10. Body member is provided by an elongated body member, and a bore is cast longitudinally therethrough.
10. A method as claimed in Claim 9 in which an end cap is secured to the outer shell to close the open <$> mouth. 10 includes thi* step of bonding an end cap t.o the main body member and to the ends of the side walls, and forming an opening in the end cap to communicate with the bore in the main body member.
11. Λ method as claimed in Claim 10 in which the end cap is secured by adhesive.
12. Λ method as claimed in any preceding claim in which the method includes the step of casting a removable plug in the ceramic material, and removing the plug when the ceramic material is set to form a hollow bore through the main body member.
13. Λ method ;is claimed in Claim 12 in which a hole is formed in the ouler shell to conimun i c.a te with l.h bore in the main body member.
14. Λ method as claimed in any of Claims 10 to 13 in which the method includes the step of forming the outer shell having an outer side wall extending between a pair of spaced apart end caps. 15. 20. A method as claimed in Claim 19 in which the method comprises the step of forming an opening in one end cap to communicate with one end of the bore.
15. Λ method as claimed in Claim 14 in wh i ch the method i nc1udes the step of forming the ou t er she I from a sheet of mater i a I forming spaced a pa rt f o 1 d lines on the sheet of material, and bending the sheet of material along the fold lines to form four side walls. 15 dry at room tempera lure.
16. Λ method as claimed in Claims 10 to 15 in which the method includes the step of forming each end cap by vacuum formation, each end cap having a base with upstanding side members.
17. Λ method for forming a lamp base, the method comprising the following steps: forming a main body member of ceramics material,
18. Λ method as claimed in Claim 17 in which the main
19. A method as claimed in Claim 18 in which a pair of end caps are secured to the ends of the main body member and to the ends of the sleeve-like member.
20. And forming a hole through the outer shell to communicate with tin* bore. 20 5. Λ method as claimed in any preceding claim in which the method includes the step of partly forming the outer shell in sleeve form and sliding and bonding the outer shell onto the main body member.
21. A method as claimed in Claim 20 in which an electrical cable is passed through the bore and 20 through the opening in the end cap.
22. A method as claimed in Claim 21 in which a hole is drilled through the sleeve-like member, and the main body member to communicate with the bore, the electrical cable being passed through the hole.
23. Λ method as claimed in Claim 22 in which the second end cap is secured to the body member and the sleeve-like member after the electrical cable has been threaded through the bore.
24. A method as claimed in any of Claims 17 to 23 in which the method includes the step of forming the outer sleeve-like member from sheet material, the sheet material being cut to size, forming Cold lines in the sheet material to define corners of side walls, and bending the sheet of material along the fold lines to form the side walls of the sleeve-like member.
25. Λ method as claimed in any preceding claim in which the outer shell is formed from sheet material.
26. A method as claimed in Claim 25 in which the sheet material is a plastics material.
27. A method as claimed in Claim 25 or 26 in which A the sheet material is PVC.
28. A method as claimed in any preceding claim in which the ceramics material is casting clay.
29. A method as claimed in any preceding claim in which the ceramics material is potters fine casting plaster.
30. Λ method for forming a lamp base, the method comprising the steps of: forming an outer shell οΓ the lamp base by forming a sheet, of material to form a side wall of an elongated outer shell of the lamp base, forming at least one end cap of the outer shell, securing the end cap to the side wail, placing the outer shell in a support mould with an open mouth facing upwardly, inserting a removable plug to form a hollow bore i ii the out er she I 1 , forming a main body member by moulding a ceramics material in the outer shell. allowing the cerami ics material to set, remov i ng the plug. removing the outer shell from the support mould,
31. A method as claimed in Claim 30 in which a pair of end caps of the outer shell are formed, the second end cap being secured to the side wall to close the open mouth after the ceramics material has set and the plug has been removed.
32. Λ method as claimed in Claim 30 or 31 in which the method includes the step of forming spaced apart fold lines in the sheet of material to form the side I wall, and bending the sheet along the fold lines to form a plurality of side walls.
33. A method for forming a lamp base, the method comprising the steps of: forming an elongated main body member of ceramics material with a bore extending therethrough, and securing an outer sleeve-like shell to the main body member.
34. A lamp base base formed according to the method of any of the preceding claims in which the lamp base comprises an outer shell surrounding a main body member formed of ceramics material.
35. A lamp base as claimed in Claim 34 in which tho outer shell comprises a side wall extending between a pair of spaced apart end caps.
36. A lamp base as claimed in Claim 35 in which a bore extends through the main body member between the end caps, a hole being provided in one of l.h<* end caps to communicate with the bore, and a second hole being provided through the side wall and the main body member fo communicate with the bore.
37. A lamp base as claimed in any of Claims 34 to 36 in which the outer shell is of PVC material and the
38. A lamp base as claimed in any of Claims 34 to 37 in v/hich a nipple to secure a bulb holder is provided in one end cap engaging the bore.
39. A lamp base as claimed in Claim 38 in which an 10 electrical cable extends through the hole in the side wall into the bore and through the nipple.
40. A lamp base as claimed in any of Claims 34 to 39 in which the outer shell comprises four side walls.
41. Lamp bases substantially as described herein with 15 reference to and as illustrated in the accompanying drawi tigs.
42. Λ method for forming a lamp base substantially as described herein with reference to and as illustrated in the accompanying drawings.