GB2235721A

GB2235721A - Die cast model assembly

Info

Publication number: GB2235721A
Application number: GB9013277A
Authority: GB
Inventors: Frank Lawrence Joyce
Original assignee: Gilbow
Current assignee: Gilbow
Priority date: 1989-06-22
Filing date: 1990-06-14
Publication date: 1991-03-13
Anticipated expiration: 2010-06-14
Also published as: HK69494A; GB9013277D0; GB8914315D0; GB2235721B

Abstract

A die cast model assembly comprising at least first and second parts 1, 2 held together by a pin 11 having a head 10 at one end retained in the first part, the end of the pin remote from the head having a plurality of peripheral flanges 18 and being disposed within a socket in the second part, and a bush 15 located over the end of the pin remote from the head within the socket as an interference fit with the pin in order to fix at least the first and second parts permanently together. <IMAGE>

Description

DIE CAST MODEL ASSEMBLY The present invention relates to the assembly of die cast models such as model vehicles and, more particularly., relates to a novel assembly method which enables greater authenticity or accuracy of the models to be achieved.

A particular problem with die cast models which comprise multiple parts, resides in permanently and securely fixing the parts together so that they do not readily come apart. This is usually achieved by providing elongate bosses on one part which extend through an aperture in the other part and which are then hammmered over at their ends like a rivet in order to fix the parts together. An alternative construction uses elongate rivets. Unfortunately, the requirement to provide bosses integral with a surface of one of the parts on the interior of the part, can result in indentations or the like in the outer surface of the finished product. Furthermore, since the forces involved in hammering over the end of the elongate bosses or rivets are high, the wall portions of the model parts have to be of a thickness which is capable of withstanding the forces involved.In the past this has meant that wall thicknesses are much greater than is necessary simply to ensure sufficient rigidity in the model parts and this may lead to parts being of a thickness which is very much out of scale in comparision with the original which the model is intended to replicate. Thus, not only is there a greater volume of the die casting material used in the model, but it may also be substantially out of scale in certain areas.

In order to overcome this problem and in accordance with the present invention, a die cast model assembly comprises at least first and second parts, at least the first and second parts being held together by a pin having a head at one end retained in the first part, the end of the pin remote from the head having a plurality of peripheral flanges and being disposed within a socket in the second part; and a bush located over the end of the pin remote from the head within the socket as an interference fit with the pin in order to fix at least the first and second parts permanently together.

Preferably, the flanges will have the form of symmetrical protrusions having thus a barb-like form for engagement with the sides of a bore in the bush. The bush is preferably of a suitable plastics material and is arranged to be fully located within the socket in the second part and, after insertion into the socket and engagement with the flanged end of the pin, forms a permanent connection with the pin thus retaining at least the first and second parts in a permanently engaged position.

Plural pin and bush assemblies may be provided where required.

Preferably the first and second parts are top and bottom parts of the model, but in an alternative construction falling within the terms of the present invention, the first and second parts are wheels of the model.

According to a second aspect of the invention therefore a die cast model assembly comprises first and second wheels disposed on an axle pin, each of the wheels having a blind bore engaging over a respective end of the pin, each end of the pin having plural peripheral flanges providing an interference fit with the respective bore in order to permanently fix and retain the wheels on the axle.

Particular advantages of the invention result from the lower fixing forces which are involved in assemblying the models together, to the extent that the wall portions and the like of the model can be formed of thinner section, saving molding material and, at the same time, improving model accuracy. In connection with the second aspect of the invention the location of the ends of the axial pin in blind bores in the wheels significantly improves authenticity of the hub or central part of each wheel.

One example of a model assembly constructed in accordance with the present invention will now be described with reference to the accompanying informal drawings in which:- Figure 1 is a longitudinal centre section; Figure 2 is a pair of half sections on lines B-B and C-C in Figure 1; and, Figure 3 is an exploded enlarged view of the pin and bush assembly fixing.

The model shown is a double-decker London bus (in Oo scale, ie 1:76) and comprises a pair of die cast model halves 1,2 (formed in conventional zinc alloy, eg Mazak), together with a floor pan 3, a lower seating deck 4, a spacer and ceiling 5, upper seating deck 6 and lower and upper transparent window-forming portions 7,8. These latter, non-die cast parts are preferably made of synthetic plastics material which is coloured appropriately or is transparent in the case of the window portions 7,8.

In order to permanently fix the model assembly together the roof of the upper housing 1 is formed with a pair of small downwardly extending bosses 9 into which are fitted the head ends 10 of mild steel pins 11 of diameter 1.83 mm. To retain the head 10 within the bosses 9 the bosses are crimped over the underside of the heads 10.

Each of the lower and upper seating decks, the ceiling and the floor pan has apertures (aligned when assemblied) through which the pins 11 may pass. In the case of the floor pan 3 sockets 12 forming recesses in the underside of the floor pan are provided. The free ends 13 of the pins 11 have annular barb-like flanges or buttresses 18 of enlarged diameter (eg 2.01 mm) (see Figure 3) projecting therefrom and these are engaged with the sides of bores 14 formed in plastics bushes 15 (preferably formed in ABS) which locate in the sockets 12 and provide an interference fit with the free ends 13 of the pins 11 on assembly, the nominal bore diameter of the bore 14 being that of the pin.

The number of flanges will vary according to precise application and the angle on the flanges may be, for example, between 30 0 and 450.

Pushing the plastic bushes 15 onto the pins 11 requires considerably lower force than is necessary for fixing in conventional die cast models and this, in turn, enables the wall thickness of the two die cast parts 1, 2 to be reduced and in particular this applies to the window pillar 16 separating the respective window apertures 17.

Greater authenticity and lower material costs result.

More particularly as shown in Figure 2, the wheels 20 are fixed together in similar fashion. Each of the wheels includes a hub portion 21 and a tyre portion 2. The hub 21 has a blind bore 23 and into each bore is fitted one end of a respective axle pin 24 of diameter 1.83 mm. As in the case of the pins 11 the axle pins 24 have flanged ends 25 which form interference fits with the bores 23 in the respective wheels 20. The provision of blind bores 23 enables the external surface of the wheel to accurately represent the wheel on the full size bus to a much greater degree than was previously possible.

Claims

1. A die cast model assembly comprising at least first and second parts held together by a pin having a head at one end retained in the first part, the end of the pin remote from the head having a plurality of peripheral flanges and being disposed within a socket in the second part, and a bush located over the end of the pin remote from the head within the socket as an interference fit with the pin in order to fix at least the first and second parts permanently together.

2. An assembly according to clam 1, wherein the flanges have the form of symmetrical protrusions having thus a barb-like form for engagement with the sides of a bore in the bush.

3. An assembly according to claim 1 or claim 2, wherein the bush is formed of a plastics material and is arranged to be fully located within the socket in the second part and, after insertion into the socket and engagement with the flanged end of the pin, forms a permanent connection with the pin thus retaining the at least first and second parts in permanent engagement.

4. An assemblt according to any of claims 1 to 3, wherin plural pin and bush assemblies are provided to retain the engagement between the at least first and second parts.

5. An assembly according to any of claims 1 to 4, wherein the first and second parts are top and bottom parts of the model.

6. An assembly according to any of claims 1 to 4, wherein the first and second parts are wheels of the model.

7. A die cast model assembly having first and second wheels disposed on an axle pin, each of the wheels having a blind bore engaging over a respective end of the pin, each end of the pin having plural peripheral flanges providing an interference fit with the respective bore in order to permanently fix and retain the wheels on the axle.

8. A die cast model assembly substantially as described with reference to the accompanying drawings.