MECHANISM FOR REPEATEDLY LAUNCHING AND CATCHING A PROP

Abstract

A mechanism for repeatedly launching and catching a prop includes a base, a launch tube supported by the base, a prop including a prop body with a recess that at least partially receives the launch tube when the prop is in a static position, and at least one guide element passing through the base and along the prop. The at least one guide element is configured to be anchored over the base. A launch system is arranged to apply a launching force to the prop to dynamically propel the prop along the at least one guide element. A bounce plate is supported by the base. The bounce plate is arranged radially outwardly of the launch tube and arranged to make contact with and catch the prop when the prop falls back to the base.

Description

FIELD

The present disclosure relates to the field of novelty devices, theatrical props, and startle scare attractions and, more particularly, to a pneumatic mechanism for repeatedly launching and catching a prop to provide a startle scare.

BACKGROUND

This section provides background information related to the present disclosure which is not necessarily prior art.

Consumers purchase a wide variety of novelties and props for various holidays. Many of the novelties and props are used in interior and/or exterior spaces around a place of residence or business. In some cases, the novelties and props are used in specific themed events such as haunted houses or decorations/displays for Halloween and the like. The specific themed events may likewise be set up in interior and/or exterior spaces. Novelties and props may be static, dynamic, or a combination of static and dynamic. Similar devices/props can be used in the commercial setting, as theatrical props for commercial haunted houses, amusement parks/attractions, plays, and motion pictures.

Movement embodied by dynamic novelties and props tend to draw more attention than static novelties and props. As such, many consumers or decorators try to incorporate dynamic novelties and props into their displays. Many consumers and decorators seek out dynamic novelties and props that will add interest to their displays, generate a more realistic/life-like display/attraction, and/or that will scare/startle observers. As such, there is a growing demand for more and unique dynamic novelties/props to meet the needs of current consumers.

Traditional dynamic displays/attractions utilize liner actuators to move props or portions of a display. These linear actuators typically have a limited stroke length of less than three feet (36 inches) and exhibit a hard stop at the end of their stroke. The hard stop tends to damage props after repeat use cycles because props are often made of brittle and/or delicate materials, such as poly foam or silicone, and are therefore prone to damage from repeated, hard decelerations. Thus, there is also a need for a startle scare mechanism that can reliably and repeatedly launch a prop into the air and catch it without damaging the prop after repeated use cycles.

SUMMARY

This section provides a general summary of the disclosure and is not a comprehensive disclosure of its full scope or all of its features.

The mechanism described herein repeatably launches a prop into the air (several feet), achieving a zero impact apex, and catches the prop softly as it falls back to a base assembly to provide a startle scare (i.e., Halloween/theatrical attraction). The mechanism includes a base with a launch tube that extends vertically to an upper end, a shuttle with a lift chamber that slides down over the upper end of the launch tube, a prop (i.e., a mannequin head) mounted to the shuttle, and at least one guide element. The at least one guide element extends from the base, passes through the shuttle and/or the prop, and ends at an upper mount. The at least one guide element may be a pair of guide wires that run parallel to one another between the base and the upper mount and that pass through a strike plate, the shuttle, and the prop so that the shuttle always returns/lands with the upper end of the launch tube being slidably received in the lift chamber, and where the guide wire(s) are tensioned using winches.

The launch tube is connected to a pressurized air source such that the upper end of the launch tube is configured to discharge pressurized air into the lift chamber and propel the shuttle and prop upwards along the guide wire(s) and away from the base. The pressurized air source may be regulated by a solenoid operated valve that is positioned in the base and that is connected to a lower end of the launch tube.

The base includes a bounce plate that extends around the launch tube and that is suspended with respect to the base via resilient/elastic elements, the bounce plate is positioned to make contact with and catch the shuttle when the shuttle and prop fall back towards the base under the effect of gravity. The bounce plate is supported by a launch system support that is moveable relative to the base for alignment adjustment with the upper mount. The base may include a base frame and has an area that is configured to receive a stack of weights for ballast and the launch system support may include a plurality of support posts to which the resilient/elastic elements are attached.

The shuttle includes a strike plate at its lower end and both the strike plate, and the shuttle are made of carbon fiber reinforced nylon. The prop may be made of polypropylene foam or PLA and many of the other components of the mechanism are made of weather/UV resistant PETG.

Further areas of applicability will become apparent from the description provided herein. The description and specific examples in this summary are intended for purposes of illustration only and are not intended to limit the scope of the present disclosure.

DRAWINGS

The drawings described herein are for illustrative purposes only of selected embodiments and not all possible implementations and are not intended to limit the scope of the present disclosure.

FIG. 1 is a front perspective view of a mechanism for repeatedly launching and catching a prop, which is constructed according to the present disclosure;

FIG. 2 is an exploded perspective view of the mechanism shown in FIG. 1;

FIG. 3 is a front perspective view of a base of the mechanism shown in FIG. 1;

FIG. 4 is a front perspective view of a base plate secured to the base shown FIG. 3;

FIG. 5 is a front perspective view of a base plate bracket connecting the base plate shown in FIG. 4 to the base shown in FIG. 3;

FIG. 6 is a side elevation view of a launching system mounted to the base plate shown in FIG. 4;

FIG. 7 is a front perspective view of a bounce plate mounted to the base plate and base assembly shown in FIG. 5;

FIG. 8 is a side perspective view of a shuttle assembly of the mechanism shown in FIG. 2; and

FIG. 9 is an exploded perspective view of the shuttle assembly shown in FIG. 8.

Corresponding reference numerals indicate corresponding parts throughout the several views of the drawings.

DETAILED DESCRIPTION

Example embodiments will now be described more fully with reference to the accompanying drawings.

A mechanism 10 for repeatedly launching a prop 22 into the air and catching it softly is generally illustrated in FIGS. 1 and 2. Mechanism 10 includes a base 13 supporting a launch tube 16 and a bounce plate assembly 20. A prop 22 is positioned on launch tube 16 and rests on bounce plate assembly 20. Prop 22 may be formed from a variety of materials including polypropylene foam, polyester foam such as PLA or the like. In the non-limiting example shown, prop 22 is shown in the form of a mannequin head 24. It should however be readily understood that the prop 22 may take on a variety of forms and need not be limited to a mannequin head. In accordance with the present disclosure, mechanism 10 may repeatedly launch prop 22 upwardly into the air. Prop 22 is then caught by bounce plate assembly 20. Bounce plate assembly 20 cushions the return of prop 22 to a static or rest position. Bounce plate assembly 20 also absorbs any impact forces developed when the prop 22 lands back on the base 13. In a non-limiting example, a guide element 28 controls the travel path of prop 22 to ensure repeatability and accurate capture.

With additional reference to FIG. 3, base 13 includes a plurality of support members 31. Each of the plurality of support members 31 includes a first end portion 33 and a second end portion 35. Each first end portion 33 may be provided with an adjustable leveling foot 37. Base 13 includes a plurality of lower connecting members 43 and a plurality of upper connecting members 45. The plurality of lower connecting members 43 join each of the plurality of support members 31 adjacent to first end portion 33. The plurality of upper connecting members 45 join each of the plurality of support members 31 at second end portion 35. A corner gusset 46 is positioned between each of the plurality of upper connecting members 45 and second end portion 35 of the corresponding one of the plurality of support members 31. Each corner gusset 46 includes a mounting hole 47. The base 13, lower connecting members 43, and upper connecting members 45 may be made from a variety of materials including metal, carbon fiber, and/or carbon fiber reinforced nylon. Base 13 may include external cover panels, such as shown at 48 in FIG. 1. The external cover panels 48 may be secured to support members 31 through a variety of mechanisms including the use of mechanical fasteners, Velcro, snaps, and the like. An advantage of the mechanism 10 described herein is that the base 13 is small in size and inconspicuous such that it can easily be obscured/hidden from view, which is important for generating a startle scare and also adds to the attractiveness of the display.

With additional reference to FIG. 4, a launch system support 49 is mounted to base 13. The launch system support 49 may be formed of various materials, such as metal, carbon fiber, and/or carbon fiber reinforced nylon and includes a central launch tube passage 54, a pair of guide element openings 57 that are spaced radially outwardly of central launch tube passage 54, and a plurality of mounting passages, one of which is indicated at 59. The launch tube 16 may be rigidly mounted in the launch tube passage 54, by a threaded connection for example. Each mounting passage 59 is positioned to align with corresponding mounting holes 47 in the corner gussets 46 of the base 13.

With additional reference to FIG. 5, a mounting bracket 68 clamps the launch system support 49 to upper connecting members 45. Further, each mounting passage 59 includes a diameter that is larger than the corresponding mounting hole 47. The difference in size allows the position of the launch system support 49 to be adjusted relative to the base 13, which provides fine tuning once the base 13 is installed since alignment of the various components at the mechanism 10 is important to ensure repeatability of proper launch and landing of the prop 22. The launch system support 49 may also include a plurality of support posts 60. Each support post 60 includes a hook element 64. The mounting bracket 68 may be formed from a variety of materials including metal, carbon fiber, or carbon fiber reinforced nylon. A plurality of fasteners, one of which is indicated at 70, pass through corresponding mounting holes 47, mounting passages 59, and the mounting bracket 68. After the launching system support 49 is properly aligned, the fasteners 70 are tightened to exert a clamping force on the launch system support 49 between the corner gussets 46 and mounting bracket 68 to secure the launch system support 49 to the base 13.

With additional reference to FIG. 6 and with continued reference to FIG. 5, the launch system support 49 includes a first surface 77 and a second surface 79. First surface 77 defines an upper surface (not separately labeled) of the launch system support 49 while second surface 79 defines a lower surface (also not separately labeled) of the launch system support 49. A launch system 82 is mounted to second surface 79 such that the launch system 82 hangs from the launch system support 49. Launch system 82 includes a valve 85 that is connected in fluid communication between launch tube 16 and a connector 87. As will be appreciated to those skilled in the art, the connector 87 is adapted to be reconnected in fluid communication to a pressurized fluid source 91, which may be a pressurized air source, such as a compressed air bottle or tank or an air compressor.

In a non-limiting example, the valve 85 may be a solenoid valve that is connected in fluid communication to the pressurized fluid source 91. The pressurized launching fluid may be compressed air that applies a launching force to prop 22 when the valve 85 is opened. Solenoid valve 85 may be electrically connected to a launch controller 94. Launch controller 94 selectively actuates solenoid valve 85 to open, releasing an amount of pressurized launching fluid through launch tube 16 to launch prop 22. Launch controller 94 may be manually activated, for example, by a switch (not shown), which may be connected to a smart device through a wireless or Bluetooth® connection, or may be programmable (e.g., on a timer) and not require an external control signal.

In addition to launch system 82, the second surface 79 also supports a first winch assembly 96 and a second winch assembly 98. First winch assembly 96 includes a first spool 104 connected to a first winder 106 and second winch assembly 98 includes a second spool 108 connected to a second winder 110. Guide element 28 includes a first guide wire 112 and a second guide wire 114. At least a portion of the first guide wire 112 is wound about the first spool 104 and at least a portion of the second guide wire 114 is wound about the second spool 108. First guide wire 112 includes a first end section 116 connected to first spool 104 and a second end section 117 (FIG. 2). Second guide wire 114 includes a third end section 118 connected to second spool 108 and a fourth end section 119 (FIG. 2).

First guide wire 112 extends from the first winch assembly 96 through the pair of guide element openings 57 formed in the launch system support 49, through the prop 22, and is secured above the base 13 as will be detailed more fully herein. Similarly, second guide wire 114 extends from the second winch assembly 98 through the pair of guide element openings 57 formed in the launch system support 49, through the prop 22, and is secured above the base 13. In addition, the first and second winch assemblies 96, 98 may include corresponding first and second ratcheting locks 124 and 126 that prevent the first guide wire 112 and second guide wire 114 from coming loose once tightened.

As shown in FIG. 2, guide element 28 further includes a guide wire support member 120 that has a first guide wire support 133 and a second guide wire support 135. The first guide wire support 133 takes the form of a first hook (not separately labeled) that is connected to second end section 117 of first guide wire 112. The second guide wire support 135 takes the form of a second hook (also not separately labeled) that is connected to fourth end section 119 of second guide wire 114. While described as being hooks, the particular form that each guide wire support 133, 135 may take can vary. Guide wire support member 130 may also include a hangar 141 that may be connected to an anchor secured above the base 13.

When fully installed/set up, the first guide wire 112 and second guide wire 114 run substantially parallel to one another. When taking down mechanism 10, the first guide wire 112 and the second guide wire 114 may be rewound onto the first spool 104 and second spool 108 through manipulation of first winder 106 and second winder 110, respectively. At this point, it should be understood that while the guide element 28 is shown to include first guide wire 112 and second guide wire 114, the number of guide wires may vary and could be as few as a single guide wire.

With additional reference to FIG. 7 the bounce plate assembly 20 is shown. In accordance with the present disclosure, bounce plate assembly 20 includes a bounce plate 128 that is suspended over the base 13 by one or more resilient support elements 138. A bounce pad 129, formed from a thermoplastic material such as, thermoplastic polyester (PETG), may optionally be placed on top of the bounce plate 128. The particular material may vary. Bounce plate 128 is coupled to the resilient support element(s) 138 and is therefore suspended above the first surface 77 of the launch system support 49. The resilient support element(s) 138 may take the form of elastic bands 140 that are connected between bounce plate 128 and each of the plurality of support posts 60. Each elastic band 140 includes a first band end 142 coupled to bounce plate 128 and a second band end 144 engaged with a corresponding hook element 64 arranged on support posts 60. Bounce plate 128 may include a plurality of notches 146 that are arranged (i.e., positioned) to accommodate first guide wire 112 and second guide wire 114 as will become more fully evident herein. As shown in FIG. 2, the bounce plate assembly 20 may optionally include a bounce pad 147 that is positioned on top of the bounce plate 128. The bounce pad 147 may be made of a resilient material, like neoprene, and may be substantially the same shape as the bounce plate 128.

With additional reference to FIGS. 8 and 9 a shuttle assembly 148 that forms a sliding interface between the prop 22 and the launch tube 16 is shown. Shuttle assembly 148 includes a shuttle body 154 having an outer diameter that is received in a recess 155 formed in prop 22. Shuttle body 154 includes a shuttle strike cavity plate 156 and a lower surface 158 including a plurality of castellations 160. A first passage 162 extends longitudinally from one of the plurality of castellations 160 through shuttle body 154. A second passage 164 extends longitudinally from another of the plurality of castellations 160 through shuttle body 154. The first guide wire 112 and second guide wire 114 pass through the first and second passages 162, 164 in the shuttle body 154 and/or through the prop 22.

The shuttle assembly 148 includes a strike plate 166 that includes a strike base plate 178 and a strike plate tube 168 that extends up from the strike plate base 178 and is configured (sized) to receive at least part of the launch tube 16 when the prop 22 is in the static position. The strike plate tube 168 defines a lift chamber 184 that receives launching fluid (e.g., pressurized air) from the launch tube 16 when valve 85 is opened. The strike plate base 178 also includes a plurality of projections 170 that may nest within corresponding castellations 160 in the shuttle body 154, respectfully. At least two of the plurality of projections 170 may include guide wire openings 172A and 172B that receive the first guide wire 112 and second guide wire 114, respectively.

The strike plate base 178 may also include an impact funnel 180 that has a frustoconical shape and that leads to the lift chamber 184. The impact funnel 180 helps guide the shuttle assembly 148 into alignment with the launch tube 16 as the prop 22 falls back to a static position and also helps dissipate the impact force by receiving glancing blows from the launch tube 16 as the shuttle assembly 148 slides down over the launch tube 16 as the prop 22 makes landing.

In a non-limiting example, mechanism 10 may be installed/set up by positioning base 13 on a support surface. The support surface may be an interior surface or an exterior surface, such as the ground. Base 13 may be secured to the support surface by anchors or be laden with weights such as bar-bell weights or metal plates/discs. At this point, first guide wire 112 is unspooled from first winch assembly 96, passed through one of the guide element opening 57 formed in the launch system support 49, then through guide wire opening 172A in the strike plate 166, through the first passage 162 in shuttle body 154, and connected to first guide wire support 133 on guide wire support member 130. Similarly, second guide wire 114 may be unspooled from second winch assembly 98, passed through the other guide element opening 57 formed in the launch system support 49, then through guide wire opening 170B in the strike plate 166, through the second passage 164 in shuttle body 154, and then connected to second guide wire support 135 of guide wire support member 130. The shuttle is then positioned on bounce plate 128 with launch tube 16 extending into the lift chamber 184.

At this point, guide wire support member 130 may be anchored above the base 13 and the first guide wire 112 and second guide wire 114 are tightened by rotating first winder 106 and second winder 110, respectively. Pressurized fluid source 91 may be connected to valve 85 and the launch controller 94 powered. The launch controller 94 may be activated to launch prop 22, where the launch controller 94 opens. Valve 85 releases compressed air through launch tube 16, and into the lift chamber 184, which applies a launching force to the prop 22. At this point, prop 22 travels upwardly to a zero impact apex constrained by first guide wire 112 and second guide wire 114.

After reaching the zero impact apex, prop 22 travels downwardly, along first guide wire 112 and second guide wire 114 under the force of gravity. Prop 22 is then gently caught on bounce plate 128 with any developed impact forces being cushioned by the plurality of elastic bands 143. In the static (rest) position, launch tube 16 is again arranged in the lift chamber 184 and prop 22 is ready for another launch. Prop 22 may be repeatedly launched and caught with this system. Advantageously, the launch tube 16 and bounce plate 128 never make contact with the prop 22. All contact is with the launch tube 16 and the bounce plate 128 is limited to the strike plate 166 and/or the shuttle body 154, which are more durable than the prop 22. For example, and without limitation, the strike plate 166 and/or the shuttle body 154 may be made of thermoplastic polyester (PETG) or other durable materials. This design also easily accommodates a wide range of props 22, since the prop 22 can be removed from the shuttle assembly 148 and swapped out for a different one or a replacement.

Exemplary embodiments are provided so that this disclosure will be thorough and will fully convey the scope to those who are skilled in the art. Numerous specific details are set forth such as examples of specific components, devices, and methods, to provide a thorough understanding of embodiments of the present disclosure. It will be apparent to those skilled in the art that specific details need not be employed, that example embodiments may be embodied in many different forms and that neither should be construed to limit the scope of the disclosure. In some example embodiments, well-known processes, well-known device structures, and well-known technologies are not described in detail.

The terminology used herein is for the purpose of describing particular example embodiments only and is not intended to be limiting. As used herein, the singular forms “a,” “an,” and “the” may be intended to include the plural forms as well, unless the context clearly indicates otherwise. The terms “comprises,” “comprising,” “including,” and “having,” are inclusive and therefore specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. The method steps, processes, and operations described herein are not to be construed as necessarily requiring their performance in the particular order discussed or illustrated, unless specifically identified as an order of performance. It is also to be understood that additional or alternative steps may be employed.

When an element or layer is referred to as being “on,” “engaged to,” “connected to,” or “coupled to” another element or layer, it may be directly on, engaged, connected or coupled to the other element or layer, or intervening elements or layers may be present. In contrast, when an element is referred to as being “directly on,” “directly engaged to,” “directly connected to,” or “directly coupled to” another element or layer, there may be no intervening elements or layers present. Other words used to describe the relationship between elements should be interpreted in a like fashion (e.g., “between” versus “directly between,” “adjacent” versus “directly adjacent,” etc.). As used herein, the term “and/or” includes any and all combinations of one or more of the associated listed items.

Although the terms first, second, third, etc. may be used herein to describe various elements, components, regions, layers and/or sections, these elements, components, regions, layers and/or sections should not be limited by these terms. These terms may be only used to distinguish one element, component, region, layer or section from another region, layer or section. Terms such as “first”, “second”, and other numerical terms when used herein do not imply a sequence or order unless clearly indicated by the context. Thus, a first element, component, region, layer or section discussed below could be termed a second element, component, region, layer or section without departing from the teachings of the example embodiments.

Spatially relative terms, such as “inner”, “outer”, “beneath”, “below”, “lower”, “above”, “upper”, and the like, may be used herein for ease of description to describe one element or feature's relationship to another element(s) or feature(s) as illustrated in the figures. Spatially relative terms may be intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if the device in the figures is turned over, elements described as “below”, or “beneath” other elements or features would then be oriented “above” the other elements or features. Thus, the example term “below” can encompass both an orientation of above and below. The device may be otherwise oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein interpreted accordingly.

The terms “about” and “substantially” are intended to include the degree of error associated with measurement of the particular quantity based upon the equipment available at the time of filing the application. For example, “about” and/or “substantially” can include a range of ±8% of a given value.

The foregoing description of the embodiments has been provided for purposes of illustration and description. It is not intended to be exhaustive or to limit the disclosure. Individual elements or features of a particular embodiment are generally not limited to that particular embodiment, but, where applicable, are interchangeable and can be used in a selected embodiment, even if not specifically shown or described. The same may also be varied in many ways. Such variations are not to be regarded as a departure from the disclosure, and all such modifications are intended to be included within the scope of the disclosure.

Claims

1. A mechanism for repeatedly launching and catching a prop, comprising:

a base;

a launch tube supported by the base;

a prop including a prop body with a recess that at least partially receives the launch tube when the prop is in a static position;

at least one guide element passing through the base and along the prop, the at least one guide element being configured to be anchored over the base;

a launch system arranged to apply a launching force to the prop to dynamically propel the prop along the at least one guide element; and

a bounce plate supported by the base, the bounce plate being arranged radially outwardly of the launch tube and arranged to make contact with and catch the prop when the prop falls back to the base.

2. The mechanism according to claim 1, wherein the bounce plate is suspended above the base by at least one resilient support element.

3. The mechanism according to claim 1, wherein the base includes a plurality of support posts a plurality of elastic bands that extend between the bounce plate and the plurality of support posts.

4. The mechanism according to claim 1, further comprising a shuttle arranged in the recess of the prop body to define a sliding interface between the launch tube and the prop.

5. The mechanism according to claim 4, wherein the shuttle includes a shuttle body that is received in and abuts the recess in the prop and a strike plate having a strike plate base that is arranged to make contact with the bounce plate and a tubular structure that extends from the strike plate base to define a lift chamber that is sized to slide over at least part of the launch tube when the prop moves to the static position.

6. The mechanism according to claim 5, where the strike plate base includes an impact funnel that leads to the lift chamber.

7. A mechanism for repeatedly launching and catching a prop, comprising:

a base;

a launch tube supported by the base;

a prop including a prop body with a recess that at least partially receives the launch tube when the prop is in a static position;

at least one guide element extending from the base;

a launch system arranged to apply a launching force to the prop to dynamically propel the prop along the at least one guide element; and

a bounce plate suspended over the base, the bounce plate being arranged radially outwardly of the launch tube and arranged to make contact with and catch the prop when the prop falls back to the base.

8. The mechanism according to claim 7, wherein the at least one guide element includes a guide wire having a first end section supported in the base and a second end section configured to be anchored over the base.

9. The mechanism according to claim 8, further comprising a winch assembly supported in the base, the first end section of the guide wire being connected to the winch assembly.

10. The mechanism according to claim 9, wherein the winch assembly includes a spool about which at least a portion of the guide wire is wound.

11. The mechanism according to claim 7, wherein the at least one guide element includes a first guide wire having a first end section attached to the base and a second end section configured to be anchored above the base and a second guide wire having a third end section attached to the base and a fourth end section configured to be anchored above the base.

12. The mechanism according to claim 11, wherein the first guide wire and the second guide wire run substantially parallel to one another in an installed configuration.

13. The mechanism according to claim 11, further comprising a first winch assembly supported in the base, the first end section of the first guide wire being connected to the first winch assembly, and a second winch assembly supported in the base, the third end section of the second guide wire being connected to the second winch assembly.

14. The mechanism according to claim 13, wherein the first winch assembly includes a first spool about which at least a portion of the first guide wire is wound, and the second winch assembly includes a second spool about which at least a portion of the second guide wire is wound.

15. The mechanism according to claim 11, further comprising a guide wire support member including a first guide wire support configured to receive the second end section of the first guide wire and a second guide wire support configured to receive the fourth end section of the second guide wire.

16. The mechanism according to claim 15, wherein the guide wire support member includes a hanger configured to connect with an anchor to hang the guide wire support member above the base.

17. The mechanism according to claim 11, wherein the first and second guide wires pass through the prop body.

18. The mechanism according to claim 17, wherein the first and second guide wires extend through notches in the bounce plate to keep the bounce plate centered around the launch tube.

19. The mechanism according to claim 7, wherein the launching force is generated by forcing compressed air through the launch tube and into the recess in the prop body, wherein a supply of compressed air is connected in fluid communication with the launch tube.

20. The mechanism according to claim 19, further comprising a solenoid valve connected in fluid communication between the supply of compressed air and the launch tube, the solenoid valve being selectively activatable to deliver the compressed air through the launch tube and into the recess in the prop.