FR2737291A1 - PYROTECHNIC RIDING - Google Patents

Abstract

The pyrotechnic merry-go-round according to the invention comprises a plate (1) rotatably mounted on a vertical shaft (2) carried by a base (3). The plate (1) carries pyrotechnic fountains (4, 5) oriented upwards and slightly inclined. The shaft (2) comprises an upper end (8) in a needle, an upper section (9) with a helical external thread (10), and a smooth lower section (11) with reduced diameter. The plate (1) is integral with a blind coaxial sleeve (12) comprising a lower inlet portion (13) with internal thread engaged on the external thread (10) of the shaft (2), and an intermediate portion ( 14) with an enlarged diameter extending to an upper bottom (15). The external helical thread (10) causes rotation of the plate (1), which then continues when the lower inlet portion (13) is opposite the lower smooth portion (12) of the shaft (2) and the the upper end (8) of the shaft (2) bears against the bottom (15) of the sleeve (12).

Description

PYROTECHNIC RIDING

  The present invention relates to pyrotechnic devices for carrying and rotating one or more pyrotechnic fountains, to produce a firework with sun effects or

S umbrella.

  We know in particular such a pyrotechnic device described in document US-A-1 617 084, in which a plate is rotatably mounted on a horizontal shaft. The plate is formed of a lattice of several branches carrying several pyrotechnic fountains, some of which are oriented radially and others are oriented tangentially. Tangential fountains produce both a pyrotechnic effect, and the

  rotation of the plate around its tree.

  Such a device is suitable for achieving a sun effect, but it must imperatively be used outdoors. Indeed, the fountains necessary for the rotation and the maintenance of the rotation of the plate are necessarily outdoor fountains, whose combustion gases have sufficient energy to propel the plate, but whose use is prohibited indoors, and the orientation of the tray along a horizontal axis is also incompatible with indoor use, because of the orientation of the pyrotechnic flows leaving the fountains to the sides and down during part of the rotation of the tray. And the rotation of the plate requires the provision of tangentially oriented pyrotechnic fountains, which

increases the cost of the set.

  Indoor pyrotechnic devices require the use of small indoor fountains, which are already sold to the general public and are designed to be used safely indoors. These indoor fountains only develop a low energy of combustion gas, and for this reason, they do not constitute an effective propellant for the rotation of a tray. The problem proposed by the present invention is to design a new pyrotechnic arena, carrying one or more pyrotechnic devices having no appreciable effect on the rotation of the plate, with simple and inexpensive means, other than pyrotechnic devices, for cause and maintain the rotation of the plate

  during the combustion time of pyrotechnic devices.

  Another object of the invention is to design such a device which is particularly simple and inexpensive, so that its production cost is compatible with the low prices that buyers are ready to devote to such a device capable of being used. once or a few times. A first application may reside in indoor pyrotechnic arenas, whose indoor fountains do not by themselves allow the rotation of the tray. By its simplicity, the device must then be able to be mounted by the user himself, so as to reduce its size for packaging, transport, and

  presentation on store shelves.

  A second application may reside in external devices comprising non-propellant pyrotechnic devices or

  without propellant effect because of their non-tangential orientation.

  To achieve these and other objects, a pyrotechnic arena according to the invention comprises a turntable mounted on a

  tree, the plate carrying one or more pyrotechnic devices.

  According to the invention: - the shaft is carried by a base which keeps it in a substantially vertical position, - the shaft comprises, from an upper end shaped as a needle, an upper section with helical external thread adjacent to a section smooth bottom with reduced diameter, - the plate is integral with a blind coaxial sleeve comprising a lower entry portion with internal thread corresponding to the external thread of the shaft and adapted to let the shaft penetrate, an intermediate portion with enlarged diameter , and an upper bottom offset from the inlet portion by a distance such that the inlet portion is opposite the smooth lower section when the upper needle end of

  the shaft bears against the upper bottom of the sleeve.

  According to a preferred embodiment, facilitating the holding in position of the elements of the device during the lighting of the pyrotechnic devices, the arena also comprises removable stop means for the start of the race, to selectively oppose the descent of the platform on the tree, and to authorize said descent of the tray onto the tree

after removal of the stop.

  According to a first embodiment, the stop is a transverse fork engaged in an intermediate annular groove provided in the

upper section of the tree.

  According to another embodiment, making it possible to make automatic and simultaneous the start of rotation of the plate and the ignition of the pyrotechnic devices, the stop is a combustible cord fixed on the upper section of the shaft, and preferably connected to the pyrotechnic devices to ensure their firing. The combustion of the cord frees the plate which enters into rotation, and ignites the devices

pyrotechnics.

  Other objects, features and advantages of this

  invention will become apparent from the following description of embodiments

  individuals, made in connection with the attached figures, among which: - Figure 1 is a top view of a pyrotechnic carousel according to an embodiment of the present invention; - Figure 2 is a side view of the pyrotechnic carousel of Figure 1, in the end of combustion position of the pyrotechnic fountains; - Figure 3 is a side view in partial section of the pyrotechnic carousel of Figures 1 and 2, pyrotechnic fountains removed, in the initial position of the tray; - Figure 4 is a side view in partial section of the pyrotechnic carousel of Figures 1 and 2 in the final position of the plate; - Figure 5 is a side view in section of a sleeve for ensuring the rotation of the plate of a carousel according to the preceding figures; - Figure 6 is a top view showing the part forming the lower inlet portion of the sleeve; - Figure 7 is a side sectional view of the part of Figure 6; and - Figure 8 is a side view of the tree of the pyrotechnic carousel

  shown in Figures 1 to 4.

  In the embodiment illustrated in the figures, a pyrotechnic arena according to the invention is an indoor pyrotechnic arena comprising a plate 1 rotatably mounted on a vertical shaft 2. The shaft 2 is carried by a base 3 which keeps it in position substantially

vertical.

  The tray 1 carries two diametrically opposite indoor pyrotechnic fountains 4 and 5 whose corresponding outlet orifice 6 or 7 is preferably directed upwards, the fountains 4 and 5 being able to be inclined in a plane tangent to the rotation of the tray 1 at an inclination of between 15 and 30 approximately. The inclination of the fountains 4 and 5 is preferably made in the direction in which the thrust of the combustion gases maintains the rotation of the plate 1, as will be

explained further.

  The shaft 2 comprises an upper end 8 shaped as a needle, an upper section 9 with a helical external thread 10 adjacent to

  a smooth lower section there with reduced diameter.

  The plate 1 is integral with a blind coaxial sleeve 12, comprising a lower inlet portion 13 with internal thread 130 corresponding to the external thread 10 of the shaft 2 and adapted to allow the shaft to penetrate 2. Thus, when the plate 1 is adapted to the upper end of the shaft 2, its weight tends to cause it to descend in a helical movement generated by the engagement of the lower portion

  inlet 13 of sleeve 12 on external thread 10 of shaft 2.

  The sleeve 12 comprises an intermediate portion 14 with an enlarged diameter, making it possible to avoid any contact of friction between said

  intermediate portion 14 and the shaft 2.

  The sleeve 12 also includes an upper bottom 15, offset from the inlet portion 13 by a distance D greater than the distance D1 between the upper end 8 and the smooth lower section 11 of the shaft 2. In this way, when the upper end 8 in needle of the shaft 2 is in abutment against the upper bottom 15 of the sleeve 12, the inlet portion 13 is facing the smooth lower section 11, released from the helical external thread 10, so that the sleeve 12 can then freely continue its rotation around the shaft 2 without its rotation being disturbed by

  friction between the sleeve 12 and the shaft 2.

  In the embodiment illustrated in the figures, the helical external thread 10 of the shaft 2 has a step to the left, to ensure the rotation of the plate 1 in the anticlockwise direction when viewed from above. Obviously, it is possible, without departing from the scope of the invention, to use a helical external thread 10 with right-hand pitch, causing a reverse rotation of the plate 1. It can be seen that the orientation of the indoor fountains 4 and 5 is such that the thrust of the combustion gases maintains the rotation of the plate 1 anticlockwise, rotation caused initially by the thread

helical external 10.

  In operation, the plate 1 is initially at the start of the race, as illustrated in FIG. 3, adapted on the upper portion of the shaft 2 in the vicinity of the upper end 8 which is engaged in the sleeve 12. By the action of the helical external thread 10, on which is engaged the lower inlet portion 13 of the sleeve 12, the plate 1 tends to descend by its own weight while rotating in an anticlockwise direction. At the end of the race, as illustrated in FIG. 4, the upper end 8 of the shaft 2 comes to bear on the upper bottom 15 of the sleeve 12, which prevents further progression of the plate 1 downwards. In this position, the lower inlet portion 13 of the sleeve 12 is located opposite the smooth lower section 11 of the shaft 2, lower section devoid of external helical thread. In this position, the plate 1 freely continues its rotation, this rotation being disturbed by no significant friction between the peripheral lateral face of the shaft 2 and the internal face of the sleeve 12. The only friction occurs between the needle formed by the upper end 8 of the shaft 2 and the upper bottom 15 of the sleeve 12. This friction is very low, so that the inertia of the plate 1 allows sufficient rotation of the plate 1

  during the entire combustion period of indoor fountains 4 and 5.

  Naturally, in the operation which has just been described, the user must maintain the tray 1 in the initial position of FIG. 3 during the firing of the indoor pyrotechnic fountains 4 and 5. To facilitate the holding of the tray 1 in initial position of FIG. 3, it is advantageously possible to provide removable stop means for starting the race, selectively opposing the descent of the plate 1 on the shaft 2, and authorizing said descent of the plate 1 on the shaft 2 after removal of the stop. Such a stop means may for example be a transverse fork engaged in an intermediate annular groove 16

  provided in the upper section 9 of the shaft 2.

  Alternatively, the abutment means can advantageously be a fuel cord fixed to an intermediate portion of the upper section 9 of the shaft 2. The rotation of the plate 1 can then be ensured by the combustion of the fuel cord, that the user ignites after

  having ignited the indoor pyrotechnic fountains 4 and 5.

  In this case, the fuel cord can advantageously be connected to the indoor pyrotechnic fountains 4 and 5, to ensure their ignition. Thus, after firing the fuel cord alone, the combustion of the cord simultaneously ensures the rotation of the plate 1

  and the firing of indoor pyrotechnic fountains 4 and 5.

  In the embodiment illustrated in the figures, the coaxial sleeve 12 is offset upward relative to the plate 1, its inlet portion 13 being substantially at the level of the plate 1. This thus ensures a

  good balance of the plate 1 during its rotation.

  As illustrated in the figures, the inlet portion 13 of the sleeve 12 can advantageously be an attached washer 17, with central hole 18 of square section, the square section forming the internal thread 130 adaptable to the helical external thread 10 of the shaft 2. In this case, the shaft 2 is a rod with a twisted square section, the square section

  twisted forming the external helical thread 10.

  The shaft 2 can advantageously be made of metal, while the added washer 17 is made of a plastic material with a low coefficient of friction such as a polyamide 6-6 of nylon type. The rest of sleeve 12

can be metal.

  It is understood that such a device can be produced by assembling several assemblable parts as illustrated in FIGS. 6 to 8. The shaft 2 can simply be force-fitted into a hole made in the base 3. The sleeve 12 can also be force fitted into a central hole in the plate 1. The washer 17 can also

  be engaged in force in a bore of greater diameter of the plate 1.

  Indoor pyrotechnic fountains can be simply engaged

  in tubular supports forced into holes in the tray 1.

  Thus, one can conceive of such a merry-go-round which can be packaged in separate parts, the parts then being assembled by

the user himself.

  The tray 1 can be a full disc, as illustrated in the figures. Alternatively, one can provide an openwork tray, or a tray formed by spokes connecting a central hub at the ends carrying the indoor pyrotechnic fountains 4 and 5. One can also provide a different number of indoor pyrotechnic fountains, positioned

  so as to balance the plate 1 around its central axis of rotation.

  It is understood that, despite the low energy of the indoor pyrotechnic fountains 4 and 5, the plate 1 is automatically rotated around the shaft 2, and its rotation continues long enough to last throughout the combustion of the pyrotechnic fountains d 'interior 4 and 5, this rotation can also be maintained at least in part by the thrust of the combustion gases of

  indoor pyrotechnic fountains 4 and 5 carried by the tray 1.

  The invention also applies to outdoor pyrotechnic arenas in which we want to avoid, for cost reasons, to provide tangential propelling fountains ensuring the rotation of the plate. The plate can then carry non-propellant pyrotechnic devices such as candles, or propellant pyrotechnic devices whose orientation does not produce torque

of the plateau.

  The present invention is not limited to the embodiments which have been explicitly described, but it includes the various thereof.

  variants and generalizations contained in the field of claims

below.

Claims (8)

  1 - Pyrotechnic roundabout comprising a plate (1) rotatably mounted on a shaft (2), the plate (1) carrying one or more pyrotechnic devices (4, 5), characterized in that: - the shaft (2) is carried by a base (3) which keeps it in a substantially vertical position, the shaft (2) comprises, from an upper end (8) shaped like a needle, an upper section (9) with an external helical thread (10) adjacent to a smooth lower section (11) of reduced diameter, - the plate (1) is integral with a sleeve (12) coaxial blind having a lower inlet portion (13) with internal thread (130) corresponding to the external thread ( 10) of the shaft (2) and adapted to allow the shaft (2) to penetrate, an intermediate portion (14) of enlarged diameter, and an upper bottom (15) offset from the inlet portion (13) according to a distance such that the inlet portion (13) is opposite the smooth lower section (11) when the upper end (8) in shaft needle (2) is in support   against the upper bottom (15) of the sleeve (2).   2 - Armory according to claim 1, characterized in that it further comprises removable stop means of the start of the race, to selectively oppose the descent of the plate (1) on the shaft (2), and to authorize said descent of the plate (1) on the shaft (2) after removal of the stop.   3 - Armory according to claim 2, characterized in that the stop is a transverse fork engaged in an annular groove   intermediate (16) provided in the upper section (9) of the shaft (2).   4 - Armory according to claim 2, characterized in that the stop is a fuel cord fixed on the upper section (9) of the tree (2).   - Armory according to claim 4, characterized in that the fuel cord is connected to the pyrotechnic devices (4, 5) to ensure their ignition.   6 - Armory according to any one of claims 1 to 5,   characterized in that at least some of the pyrotechnic devices are indoor pyrotechnic fountains (4, 5) inclined in the direction where the thrust of the combustion gases keeps the plate rotating (1) around the tree (2).   7 - Armory according to any one of claims 1 to 6,   characterized in that the coaxial sleeve (12) is offset upward relative to the plate (1), its inlet portion (13) being substantially at level of the plate (1).   8 - Armory according to any one of claims 1 to 7,   characterized in that the inlet portion (13) is a washer (17) attached to a central hole (18) with a square section, the shaft (2) being a rod with a twisted square section.   9 - Armory according to claim 8, characterized in that the shaft (2) is made of metal, the attached washer (17) is made of a plastic material with a low coefficient of friction such as a polyamide 6-6 of   nylon type, the sleeve (12) is made of metal.   - Armory according to any one of claims 1 to 9,   characterized in that it comprises indoor pyrotechnic fountains (4, 5) oriented upwards and inclined in a plane tangent to the rotation of the plate at an inclination of between 15 and 30 approximately.