GB2078352A

GB2078352A - Method of manufacturing firecrackers or similar products

Info

Publication number: GB2078352A
Application number: GB8035104A
Authority: GB
Original assignee: Individual
Current assignee: Individual
Priority date: 1980-06-18
Filing date: 1980-10-31
Publication date: 1982-01-06
Also published as: BR8003818A; NL8004352A; DE3102425A1

Abstract

In making firecrackers, a first sheet, (formed for example, by vacuum forming or moulding) has a plurality of depressions which are filled with a paste comprising pyrotechnic substance, a suitable solvent (e.g. water), and a filler, a second sheet is then secured to the first (e.g. by an adhesive) so as to seal the depressions, and the resultant product is cut up to separate the individual depressions. The preferred pyrotechnic substance is silver fulminate. The first sheet may be made of any suitable material (for example a weak plastics material) and the second sheet is desirably such as will permit the passage therethrough of evaporated solvent. Drying steps may be carried out before and/or after the second sheet is secured to the first sheet. <IMAGE>

Description

SPECIFICATION Method of manufacturing firecrackers or similar products This invention relates to a method of manufacturing firecrackers or similar products.

As is well known, firecrackers are widely used the world over and are therefore produced in great numbers and need to cost very little. Thus, there exists the necessity for a highly efficient method of large-scale production of artificial fireworks, firecrackers and other pyrotechnical devices.

The principal object of the present invention is to satisfy said necessity.

Accordingly, the present invention consists in a method of manufacturing a firecracker or similar pyrotechnic device comprising the following steps, namely, forming a first sheet which presents a plurality of recesses, placing in each of said recesses a quantity of a pyrotechnical substance in paste form, securing a second sheet to said first sheet to seal each said quantity of the pyrotechnical substance in a respective recess and thereby to create an intermediate product, and thereafter subdividing the intermediate product to produce a number of separate firecrackers or similar pyrotechnic devices. Said first sheet may be so formed by vacuum forming or vacuum moulding.

Said first sheet with the pyrotechnical substance in each of its recesses may be subjected to a drying step which need not result in said substance becoming completely dried, said step being carried out before the second sheet is secured to the first sheet.

After the second sheet has been secured to the first sheet, the intermediate product may be subjected to a drying step or to another drying step.

The intermediate product, in a generally preferred embodiment of the method according to the invention, is inserted into a cutting machine which cuts the intermediate product into firecrackers or similar pyrotechnic devices each of which consists of one or more than one recess containing its sealed-in charge of said pyrotechnical substance.

The preferred pyrotechnical substance includes silver fulminate. Said substance may also include a filler such for example as sand.

The method will now be more particularly described with reference to the accompanying drawing, in which: Figure 1 illustrates in perspective a diagrammatic representation of the product of an intermediate stage of the method according to the invention, namely, two superimposed sheets in one of which depressions are formed to accommodate a pyrotechnical substance, the upper sheet being peeled back to expose some of said depressions; and Figure 2 is a cross-sectional view, on a larger scale than that of Figure 1, of a single firecracker constituted by one of said filled depressions and the respective portions of said two sheets.

Referring to the drawing, there is illustrated a first sheet 1 in which is formed a plurality of depressions 3 for the accommodation therein of a pyrotechnical substance 4. The filled depressions 3 are covered by a second sheet 2 which is adhesively connected to the first sheet 1.

The first sheet 1, which may be made of any suitable material (such for example as a weak plastics material or a weak paper), is placed on a vacuum-forming table which is then operated to create recesses by discrete areas of the sheet 1 being sucked downwardly. By way of example, said sheet 1 may measure 35 cms x 40 cms and 400 or more depressions may be created by suction.

The pyrotechnical substance 4 which is preferred contains silver fulminate which is prepared by treating silver with nitric acid and alcohol; sand is included in the substance to act as a filler. Said substance is made into a spreadable or manipulable paste by the addition of a suitable solvent. Water has been found to be a suitable solvent but others are not excluded. This paste is placed in each of the 400 or more depressions, preferably by machine.

The second sheet 2 is preferably permeable to permitvaporised solvent to be driven off during the or each partial-drying step. Moreover, the sheet 2 may have a layer of an adhesive on one face thereof which sticks to the areas of the sheet 1 around the depressions 3.

The first sheet 1 need not be subjected to vacuumforming or vacuum-moulding in order to present said 400 or more depressions. Said first sheet 1 might be given those depressions in other ways as for example by adopting the techniques used in hand-made papers (a special mould being dipped into a vat of pulp and shaken to get rid of the water, the depressions being formed in the laid fibres by the mould construction) or by using a cheap-quality paper such as newsprint which could be damped as thereafter treated to impress the depressions in the damp newsprint.

Tests carried out at the Ministry of the Army, Directorate of Research and Technical Training, Military Engineering Institute have demonstrated the complete safety of quantities of the firecracker or similar product, having been submitted in normal merchandise packaging to tests to establish its resistance to heat, flames, impact and free fall and to other tests to establish the effect of concentrated nitric and sulphuric acids, humidity and water on said packaged quantities.

The firecrackers with which this invention is concerned are of the type which explode automatically on impact with the ground or a floor. They are quite incapable of causing bodily harm and can be used indoors or outdoors.

1. Method of manufacturing a firecracker or similar pyrotechnic device comprising the following steps, namely, forming a first sheet which presents a plurality of recesses, placing in each of said recesses a quantity of a pyrotechnical substance in paste form, securing a second sheet to said first sheet to seal each said quantity of the pyrotechnical substance in a respective recess and thereby to create an intermediate product, and thereafter subdividing the

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

Claims

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION Method of manufacturing firecrackers or similar products This invention relates to a method of manufacturing firecrackers or similar products. As is well known, firecrackers are widely used the world over and are therefore produced in great numbers and need to cost very little. Thus, there exists the necessity for a highly efficient method of large-scale production of artificial fireworks, firecrackers and other pyrotechnical devices. The principal object of the present invention is to satisfy said necessity. Accordingly, the present invention consists in a method of manufacturing a firecracker or similar pyrotechnic device comprising the following steps, namely, forming a first sheet which presents a plurality of recesses, placing in each of said recesses a quantity of a pyrotechnical substance in paste form, securing a second sheet to said first sheet to seal each said quantity of the pyrotechnical substance in a respective recess and thereby to create an intermediate product, and thereafter subdividing the intermediate product to produce a number of separate firecrackers or similar pyrotechnic devices. Said first sheet may be so formed by vacuum forming or vacuum moulding. Said first sheet with the pyrotechnical substance in each of its recesses may be subjected to a drying step which need not result in said substance becoming completely dried, said step being carried out before the second sheet is secured to the first sheet. After the second sheet has been secured to the first sheet, the intermediate product may be subjected to a drying step or to another drying step. The intermediate product, in a generally preferred embodiment of the method according to the invention, is inserted into a cutting machine which cuts the intermediate product into firecrackers or similar pyrotechnic devices each of which consists of one or more than one recess containing its sealed-in charge of said pyrotechnical substance. The preferred pyrotechnical substance includes silver fulminate. Said substance may also include a filler such for example as sand. The method will now be more particularly described with reference to the accompanying drawing, in which: Figure 1 illustrates in perspective a diagrammatic representation of the product of an intermediate stage of the method according to the invention, namely, two superimposed sheets in one of which depressions are formed to accommodate a pyrotechnical substance, the upper sheet being peeled back to expose some of said depressions; and Figure 2 is a cross-sectional view, on a larger scale than that of Figure 1, of a single firecracker constituted by one of said filled depressions and the respective portions of said two sheets. Referring to the drawing, there is illustrated a first sheet 1 in which is formed a plurality of depressions 3 for the accommodation therein of a pyrotechnical substance 4. The filled depressions 3 are covered by a second sheet 2 which is adhesively connected to the first sheet 1. The first sheet 1, which may be made of any suitable material (such for example as a weak plastics material or a weak paper), is placed on a vacuum-forming table which is then operated to create recesses by discrete areas of the sheet 1 being sucked downwardly. By way of example, said sheet 1 may measure 35 cms x 40 cms and 400 or more depressions may be created by suction. The pyrotechnical substance 4 which is preferred contains silver fulminate which is prepared by treating silver with nitric acid and alcohol; sand is included in the substance to act as a filler. Said substance is made into a spreadable or manipulable paste by the addition of a suitable solvent. Water has been found to be a suitable solvent but others are not excluded. This paste is placed in each of the 400 or more depressions, preferably by machine. The second sheet 2 is preferably permeable to permitvaporised solvent to be driven off during the or each partial-drying step. Moreover, the sheet 2 may have a layer of an adhesive on one face thereof which sticks to the areas of the sheet 1 around the depressions 3. The first sheet 1 need not be subjected to vacuumforming or vacuum-moulding in order to present said 400 or more depressions. Said first sheet 1 might be given those depressions in other ways as for example by adopting the techniques used in hand-made papers (a special mould being dipped into a vat of pulp and shaken to get rid of the water, the depressions being formed in the laid fibres by the mould construction) or by using a cheap-quality paper such as newsprint which could be damped as thereafter treated to impress the depressions in the damp newsprint. Tests carried out at the Ministry of the Army, Directorate of Research and Technical Training, Military Engineering Institute have demonstrated the complete safety of quantities of the firecracker or similar product, having been submitted in normal merchandise packaging to tests to establish its resistance to heat, flames, impact and free fall and to other tests to establish the effect of concentrated nitric and sulphuric acids, humidity and water on said packaged quantities. The firecrackers with which this invention is concerned are of the type which explode automatically on impact with the ground or a floor. They are quite incapable of causing bodily harm and can be used indoors or outdoors. CLAIMS

1. Method of manufacturing a firecracker or similar pyrotechnic device comprising the following steps, namely, forming a first sheet which presents a plurality of recesses, placing in each of said recesses a quantity of a pyrotechnical substance in paste form, securing a second sheet to said first sheet to seal each said quantity of the pyrotechnical substance in a respective recess and thereby to create an intermediate product, and thereafter subdividing the intermediate product, and thereafter subdividing the intermediateproductto produce a numberofsepa- rate firecrackers or similar pyrotechnic devices.

2. Method as claimed in Claim 1, wherein said first sheet is so formed by vacuum forming or vacuum moulding.

3. A method as claimed in Claim 1 or Claim 2, wherein said first sheet with the pyrotechnical substance in each of its recesses is subjected to a drying step which need not result in said substance becoming completely dried, said step being carried out before the second sheet is secured to the first sheet.

4. A method as claimed in Claim 3, wherein, after the second sheet has been secured to the first sheet, the intermediate product is subjected to another drying step.

5. A method as claimed in any one of the preceding Claims, wherein the intermediate product is inserted into a cutting machine which cuts the intermediate product into firecrackers or similar pyrotechnic devices each of which consists of one or more than one recess containing its sealed-in charge of said pyrotechnical substance.

6. A method as claimed in any one of the preceding Claims, wherein a pyrotechnical substance comprising silver fulminate is placed in each recess in the first sheet.

7. A method of manufacturing a firecracker or similar pyrotechnic device, substantially as hereinbefore described with reference to the accompanying diagrammatic drawing.

8. The product of the method claimed in any one ofthe preceding Claims.

9. Any features of novelty, taken singly or in combination, of the embodiments of the invention hereinbefore described with reference to the accompanying diagrammatic drawing.