GB1605290A

GB1605290A - Bombs

Info

Publication number: GB1605290A
Application number: GB760671A
Authority: GB
Inventors: L Ratcliff
Original assignee: SECR DEFENCE; UK Secretary of State for Defence
Current assignee: SECR DEFENCE; UK Secretary of State for Defence
Priority date: 1972-03-13
Filing date: 1972-03-13
Publication date: 1988-04-07

Description

(71) 1, SECRETARY OF STATE FOR DEFENCE. LONDON. do hereby declare the invention, for which I pray that a patent may be granted to me, and the method by which it is to be performed, to be particularly described in and by the following statement: This invention relates to bombs.

Because of their nature the carriage and handling of bombs is hazardous. The danger from incurring a mechanical shock can be aggravated by cracks, fissures and voids within the bomb charge, as well as by heat from climate or storage environment or from kinetic heating generated when bombs are carried externally on aircraft at high speed.

It is an object of the invention to provide an improved bomb and a method of manufacture thereof whereby the bomb charge can be substantially free of internal faults and the bombs can have an improved resistance to the deleterious effects of mechanical shock or environmental heat.

A bomb casing according to the present invention comprises a hollow housing for an explosive charge, the housing having an open rear end of internal diameter at least as large as the diameter of the intended charge, an end closure for sealing the open end of the housing and for retaining the charge within the casing, and an internal heat insulating layer which envelopes the charge when the latter is positioned in the casing.

A preferred method of manufacturing a bomb, according to the present invention, comprises forming a hollow housing with one open end of internal diameter at least as large as the diameter of the intended charge, inserting within the housing a preformed charge so shaped as to leave a space all round between it and the housing, there being spacers for supporting it within the housing to maintain said all round space, inserting an end closure into the open end of the housing and introducing heat insulating material through the end closure to fill the said space.

The heat insulating material lining may comprise a foamed polyurethane material which is introduced in liquid form through a funnel passing into a hole in the end closure, which end closure also has an air relief hole, the polyurethane foaming in situ to a semi rigid state to fill the space between the charge and the housing. The lining may be about 0.25" to 1" thick on average, with a preferred range of about 0.3" to 0.75".

A method of manufacturing a bomb casing, also according to the present invention, comprises preforming a heat insulating layer within a bomb housing having an open end of internal diameter at least as large as the diameter of the intended charge, for example by a hot moulding technique.

The invention further includes a bomb comprising a hollow bomb housing having an open rear end of internal diameter at least as large as the diameter of the intended charge, an end closure to the housing, a layer of heat insulating material lining the housing and the closure, and an an explosive charge fitting within the insulating material.

The housing will usually comprise metal and may be cast or forged to shape.

This invention allows external preforming of the charge using improved charge manufacturing techniques which result in a charge substantially free of faults. Additionally it facilitates inspection of the charge and at the same time can provide mechanical shock and heat insulation of the charge when in the bomb.

An example of a bomb incorporating a hollow casing according to the invention is illustrated by the drawing accompanying the provisional specification which is a crosssectional side view.

The bomb comprises a cast steel housing 11 of generally circular cross section having a tapered nose region 12 and open rear end 13.

Cavities 14 are provided for engaging a bomb carrier. The housing 11 contains an explosive charge 15 which is separated from the housing by a heat insulating layer of foamed polyurethane resin 16. An end closure 17 is in screw thread engagement with the housing l l and closes the rear end 13. Containers 18 and 19 for conventional fuzes and exploders are located at the nose and rear of the bomb respectively.

The bomb illustrated has several advantages over the kwn, type ofl,bombt In the known type of bomb the end closure is of considerably smaller diameter than the bomb and is made to engage a corresponding hole in an inwardly directed flange or rim at the rear of the bomb casing. This makes manufacture of the casing difficult and usually requires forging and a considerable amount of machining.

Furthermore because of the rim and the small end closure the bomb can only be filled by pouring the charge into the bomb through the end closure and allowing it to cure or set within the casing. This is known to result in cracks, fissures and voids in the charge which are difficult to discover by inspection techniques and their presence can lead to premature firing of the charge. This known bomb casing construction would also render the inclusion of a heat insulating liner as now proposed very difficult. However, in the bomb illustrated the diameter of the open rear end is sufficient to permit the charge to be made externally of the casing to the appropriate shape and diameter by a standard mould and press technique. The preformed charge can then be examined externally for cracks and fissures and internal inspection for voids is also made easier without the casing.The charge is then placed into the housing where it is supported on spacers (not shown) to be concentric with the housing. The end closure is then screwed in to close the rear end. Screw plugs 20 in the end closure are then removed and the apertures left are used the one to permit passage of a polyurethane foaming resin cream from a funnel into the space between the housing and the charge and the other to permit air to escape. The cream foams and fills the space between the housing and the charge and serves both to locate the charge within the housing and to act as a heat insulating layer. The screw plugs 20 are then replaced.

In an alternative method in which the charge is of a kind which requires consolidation in the bomb casing i.e. it is not practicable to preform the charge externally of the casing, it is necessary to form the heat insulating layer within the housing before the charge is inserted. This may be done by providing a mix of uncured liner material in the housing and moulding it to shape with a heated moulding tool. After withdrawal of the tool the bomb charge is inserted and consolidated by a vibratory or like tamping technique. After consolidation-the charge is allowed to set and an end layer of heat insulating material and the end closure are fitted. In some cases setting of the charge may be accompanied by shrinkage and if so the space so formed may be filled by injecting a resinous material such as a non foaming polyurethane resin through the end closure plugs 20.

In one example the polyurethane lining was 0.7" thick, but it has been found possible in certain instances to obtain adequate insulation with a lining 0.35" thick. A thinner lining, of course permits the inclusion of more explosive within the casing.

Other heat insulating materials, such as an asbestos fibre/phenolic resin material, may be used and these will also be selected to be compatible with the corresponding bomb charge.

WHAT I CLAIM IS: 1. A bomb casing comprising a hollow housing for an explosive charge, the housing having an open rear end of internal diameter at least as large as the diameter of the intended charge, an end closure for sealing the open end of the housing and for retaining the charge within the casing, and an internal heat insulating layer which envelopes the charge when the latter is positioned in the casing.

2. A bomb casing as claimed in claim 1 and wherein the said insulating layer comprises a foamed polyurethane plastics material.

3. A bomb casing as claimed in claim 2 and wherein the average thickness of the insulating layer is between 0.25" and 1".

4. A bomb casing as claimed in claim 1 and wherein the said insulating layer comprises an asbestos fibre/phenolic resin material.

5. A bomb casing as claimed in any one of claims 1 to 4 and wherein the housing is made of metal.

6. A method of manufacturing a bomb comprising forming a hollow housing with one open end of internal diameter at least as large as the diameter of the intended charge, inserting within the housing a preformed charge so shaped as to leave a space all round between it and the housing, there being spacers for supporting the charge in the housing to maintain the said all round space, inserting an end closure into the open end of the housing and introducing heat insulating material through the end closure to fill the said space.

7. A method as claimed in claim 6 and wherein the heat insulating material comprises a foaming polyurethane material which is introduced in liquid form through a hole in the end closure, which end closure also has an air relief hole, the polyurethane foaming in situ to a semi rigid state to fill the space between the charge and the housing.

8. A method of manufacturing a bomb casing including preforming a heat insulating layer within a bomb housing having an open end of internal diameter at least as large as the diameter of the intended charge.

9. A method as claimed in claim 8 and wherein the said preforming includes hot moulding.

10. A method of making a bomb including manufacturing a casing by a method as claimed in either claim 8 or claim 9, and forming a charge within the casing.

11. A method as claimed in claim 10 and including the further steps of sealing the casing

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. type of bomb the end closure is of considerably smaller diameter than the bomb and is made to engage a corresponding hole in an inwardly directed flange or rim at the rear of the bomb casing. This makes manufacture of the casing difficult and usually requires forging and a considerable amount of machining. Furthermore because of the rim and the small end closure the bomb can only be filled by pouring the charge into the bomb through the end closure and allowing it to cure or set within the casing. This is known to result in cracks, fissures and voids in the charge which are difficult to discover by inspection techniques and their presence can lead to premature firing of the charge. This known bomb casing construction would also render the inclusion of a heat insulating liner as now proposed very difficult. However, in the bomb illustrated the diameter of the open rear end is sufficient to permit the charge to be made externally of the casing to the appropriate shape and diameter by a standard mould and press technique. The preformed charge can then be examined externally for cracks and fissures and internal inspection for voids is also made easier without the casing.The charge is then placed into the housing where it is supported on spacers (not shown) to be concentric with the housing. The end closure is then screwed in to close the rear end. Screw plugs 20 in the end closure are then removed and the apertures left are used the one to permit passage of a polyurethane foaming resin cream from a funnel into the space between the housing and the charge and the other to permit air to escape. The cream foams and fills the space between the housing and the charge and serves both to locate the charge within the housing and to act as a heat insulating layer. The screw plugs 20 are then replaced. In an alternative method in which the charge is of a kind which requires consolidation in the bomb casing i.e. it is not practicable to preform the charge externally of the casing, it is necessary to form the heat insulating layer within the housing before the charge is inserted. This may be done by providing a mix of uncured liner material in the housing and moulding it to shape with a heated moulding tool. After withdrawal of the tool the bomb charge is inserted and consolidated by a vibratory or like tamping technique. After consolidation-the charge is allowed to set and an end layer of heat insulating material and the end closure are fitted. In some cases setting of the charge may be accompanied by shrinkage and if so the space so formed may be filled by injecting a resinous material such as a non foaming polyurethane resin through the end closure plugs 20. In one example the polyurethane lining was 0.7" thick, but it has been found possible in certain instances to obtain adequate insulation with a lining 0.35" thick. A thinner lining, of course permits the inclusion of more explosive within the casing. Other heat insulating materials, such as an asbestos fibre/phenolic resin material, may be used and these will also be selected to be compatible with the corresponding bomb charge. WHAT I CLAIM IS:

1. A bomb casing comprising a hollow housing for an explosive charge, the housing having an open rear end of internal diameter at least as large as the diameter of the intended charge, an end closure for sealing the open end of the housing and for retaining the charge within the casing, and an internal heat insulating layer which envelopes the charge when the latter is positioned in the casing.

with an end layer of heat insulating material and an end closure.

12. A bomb comprising a hollow bomb housing having an open rear end of internal diameter at least as large as the diameter of the intended charge, an end closure to the housing, a layer of heat insulating material lining the housing and the closure, and an explosive charge fitting within the insulating material.

13. A bomb casing substantially as hereinbefore described with reference to the drawing accompanying the provisional specification.

14. A method of making a bomb casing as claimed in claim 8 or claim 9 and substantially as hereinbefore described with reference to the drawing accompanying the provisional specification.

15. A method of making a bomb as claimed in any one of claims 6, 7, 10 and 11 and substantially as hereinbefore described.

16. A bomb substantially as hereinbefore described with reference to the drawing accompanying the provisional specification.