Soft Toy Grenade

Abstract

A soft toy grenade has an enclosure with a sealed interior containing a fluid, the enclosure having a plurality of receptacles, each receptacle having a retracted position and an extended position, each receptacle movable from the retracted position to the extended position upon sufficient compression of the fluid by impact of the enclosure with a hard surface.

Description

FIELD OF THE INVENTION

This invention relates to toys and amusement devices. More particularly, this invention relates to toy grenades.

BACKGROUND OF THE INVENTION

Toy guns and weapons are popular with children and adults. One of the most popular are the NERF guns and bows that are manufactured and sold by Hasbro, Inc. of Pawtucket, Rhode Island. The NERF products and their closest competitors shoot foam or rubber darts and balls, and those products are often referred to as blasters or NERF blasters. Other products shoot hard plastic balls, fluid-filled capsules that burst on impact, and soft gelatin balls. All of these products emulate the behavior of real weapons with minimal harm to people and property.

Grenades are small bombs, thrown by hand or launched by a device/machine, which usually explode on impact or after a timer/fuse has expired. Many grenades are designed to throw small, damaging projectiles (sometimes called shrapnel) in all directions when they explode.

A toy grenade imitating a shrapnel effect must launch projectiles upon activation like a cluster of blasters, but it is also itself a projectile. Many people who play with toy weapons, especially blasters, do so with other people with the expectation that they will only be struck by soft projectiles. Consequently, a satisfactory toy grenade must both be entirely soft like the projectiles, but also contain mechanisms capable of launching projectiles like a blaster.

A variety of toys propel a single projectile upon activation. Examples include Johns, U.S. Pat. No. 2,960,794, Nov. 22, 1960; Koepcke et al., U.S. Pat. No. 5,205,773, Apr. 27, 1993; Gentile et al., U.S. Pat. No. 5,334,079, Aug. 2, 1994; Liu et al., U.S. Pat. No. 5,538,456, Jul. 23, 1996; Lee et al., U.S. Pat. No. 5,619,980, Apr. 15, 1997; Hudson, U.S. Pat. No. 5,928,049, Jul. 27, 1999; Fienup et al., U.S. Pat. No. 7,673,625, Mar. 9, 2010; and Kim et al., U.S. Pat. No. 9,260,223, Feb. 16, 2016. Various means of activation are described, including manual manipulation and contact with a mechanical actuator.

Some toy grenades have been brought to market that imitate the shrapnel effect of a grenade. These include a device that contains spring loaded flaps that fling projectiles https://www.amazon.com/FenglinTech-Tactical-Plastic-Modified-Crystal/dp/B07BRNM2PQ. Greeno, U.S. Pat. No. 4,944,521, Jul. 31, 1990 discloses a toy grenade with an enclosed gas cylinder that provides the force to propel gel capsules. The Lanard scatter blast https://nerf.fandom.com/wiki/Scatter Blast (Lanard) fires darts when the nose of the device impacts a surface. The Lanard Scatter Blast has foam lining to reduce harm to people and property, but all of the aforementioned toys have non-soft bodies and mechanisms.

Other explosive shrapnel emulating toys have been proposed. They include a multiplex spring driven device Mroczka et al., U.S. Pat. Appln. Publn. No. 2012/0266852, Oct. 25, 2012 with a nose trigger like the aforementioned Scatter Blast. A “Nerf Nuke” April fools hoax https://www.youtube.com/watch?v=uzck9o2lvik and non-working prop https://www.etsy.com/listing/919756321/nerf-nuke-a-thinkgeek-2014-april-fools makes no explanation of its (imaginary) mechanism. Fienup et al., U.S. Pat. No. 7,673,625, Mar. 9, 2010, FIG. 7 and FIG. 9 propose products simulating explosive shrapnel with a plurality of a disc spring launching mechanism. These proposed mechanisms and products all require non-soft components to function, elevating the risk of harm to people and property when they are incorporated into a thrown toy.

None of the above described toys discloses an entirely soft toy grenade that propels projectiles. The toy grenade disclosed herein is able to propel projectiles in all directions when activated by impact or timer, and is made entirely with soft materials. The use of entirely soft materials makes this toy much less likely to harm people or property when thrown, even if it is damaged.

SUMMARY OF THE INVENTION

The general object of this invention is to provide an improved toy grenade. A more particular object is to provide a toy grenade that propels projectiles in multiple directions when it contacts a hard surface in any orientation after being thrown and that is entirely soft in order to minimize harm to people and property.

I have invented an improved toy grenade. The toy grenade comprises: (a) an enclosure having a substantially sealed interior containing a fluid, the enclosure having a plurality of receptacles, each receptacle having a retracted position and an extended position, each receptacle movable from the retracted position to the extended position upon sufficient compression of the fluid by impact of the enclosure with a hard surface; and (b) a plurality of projectiles held in some or all of the retracted receptacles by press fit and being adapted for propulsion from the enclosure in multiple directions when the receptacles move from the retracted position to the extended position.

The toy grenade of this invention propels projectiles in multiple directions when it contacts a hard surface in any orientation after being thrown. The toy grenade is entirely soft in order to minimize harm to people and property.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a preferred embodiment of the toy grenade of this invention with the receptacles in the retracted position.

FIG. 2 is a top plan view thereof.

FIG. 3 is a side elevation view thereof.

FIG. 4 is a sectional view thereof taken along section 3-3 in FIG. 2.

FIG. 5 is a perspective view thereof in the retracted position holding a plurality of projectiles in its receptacles.

FIG. 6 is a perspective view thereof as it strikes a hard surface and propels the projectiles.

FIG. 7 is a side elevation view thereof.

FIG. 8 is a perspective view of a second embodiment of the toy grenade of this invention with the receptacles in the extended position.

FIG. 9 is a perspective view thereof in a first position in preparation for arming.

FIG. 10 is a perspective view thereof in a second position in preparation for arming.

FIG. 11 is a perspective view thereof in a third position in preparation for arming.

FIG. 12 is a perspective view thereof in a fully wound and armed position.

FIG. 13 is a perspective view thereof as it unwinds and propels its projectiles.

FIG. 14 is a perspective view of a third embodiment of the toy grenade of this invention with the receptacles in the retracted position.

FIG. 15 is a perspective view of a fourth embodiment of the toy grenade of this invention with the receptacles in the retracted position.

FIG. 16 is a perspective view of a first step in producing an exterior negative mold for manufacturing the toy grenade of this invention.

FIG. 17 is a top view thereof.

FIG. 18 is a sectional view thereof taken along section 18-18 in FIG. 17.

FIG. 19 is a perspective view of the exterior negative mold.

FIG. 20 is a top view thereof.

FIG. 21 is a sectional view thereof taken along section 21-21 in FIG. 20.

FIG. 22 is a perspective view of a mold system for producing one hemisphere of an enclosure.

FIG. 23 is top plan view thereof.

FIG. 24 is a sectional view thereof taken along section 24-24 in FIG. 23.

FIG. 25 is a perspective view of a hemisphere immediately after removal from a mold.

FIG. 26 is a bottom view thereof.

FIG. 27 is a side elevation view thereof.

FIG. 28 is a perspective view of a hemisphere after trimming.

FIG. 29 is a bottom view thereof.

FIG. 30 is a side elevation view thereof.

FIG. 31 is a perspective view of a mold system like that of FIG. 22, but cast with receptacles in the extended position.

FIG. 32 is a top view thereof.

FIG. 33 is a section view thereof taken along section 24-24 in FIG. 32.

FIG. 34 is a perspective view of an extended receptacle hemisphere after trimming.

FIG. 35 is a bottom view thereof.

FIG. 36 is a side elevation view thereof.

DETAILED DESCRIPTION OF THE INVENTION

1. The Invention In General

This invention is best understood by reference to the drawings. Referring first to FIGS. 1 to 7, a preferred embodiment of the toy grenade of this invention 100 is an enclosure with a generally spherical elastomeric structure (also known as a spheroid) having a plurality of flexible receptacles (also known as pockets) for holding projectiles. The receptacles have a retracted position as shown in FIGS. 1 to 4 and have an extended position as shown in FIGS. 5 to 7. The projectiles are held in the retracted receptacles solely by press fit with the interior walls of the receptacles. When the toy grenade is actuated by throwing it against a hard surface, the fluid inside the enclosure is compressed. The compressed fluid then pushes the receptacles from the retracted position to the extended position and propels the projectiles from the enclosure in multiple directions.

2. The Enclosure

The enclosure has a plurality of receptacles 110 for holding the projectiles. The receptacles are surrounded by non-receptacle body portions 120. The shape of the enclosure is a matter of choice. Suitable shapes include spheres, cubes, cylinders, prolate spheroids (football shaped), and the like. The shape is preferably spherical.

The preferred embodiment of the enclosure is formed of an elastomeric material. The term “elastomeric” is used herein to mean a material that is soft, flexible, resilient (able to deform and then return to its original position), and durable. The enclosure preferably has a Shore hardness on a Shore Type A durometer of 10A to 20A. The enclosure is preferably formed of silicone rubber and is most preferably formed of a platinum cure silicone rubber having about a 15 A Shore hardness on a Shore Type A durometer.

When an elastomer is used for both receptacle and non-receptacle portions of the enclosure, the non-receptacle portion must be made sufficiently thick that the enclosure easily returns to shape after deformation, but not so thick that it does not deform easily on impact. Larger enclosures require thicker material to hold and return to shape. The receptacle portion is preferably as thin as possible within constraints of durability and reliable manufacturing. Smaller receptacles for smaller projectiles require thinner material. Recommended measurements and quantities regarding the enclosure herein are suited to a toy having about 104 mm diameter, with receptacles fitting a foam projectile about 20 mm in diameter, made with an elastomer having about 15 A shore hardness. Suitable measurements and quantities should be adjusted for toys having parameters substantially different from the preceding description.

The non-receptacle body portions of the enclosure generally have a thickness that is about four to ten times the thickness of the receptacle portions. The non-receptacle body portions preferably have a thickness of about 7 to 13 millimeters (mm), and most preferably about 8 to 12 mm. The receptacle portions of the enclosure generally have a thickness of about 0.5 to 4 mm, preferably about 1 to 2 mm. Unless otherwise indicated expressly or by context, the term “about” is used herein to mean plus or minus 25 percent of the measurement or other quantified property referenced.

The enclosure contains an amount of fluid substantially sealed within it. The fluid is preferably air, but liquids and other gases are suitable. If the fluid is air, one or more small openings in the enclosure are preferred to allow a very restricted flow between the interior of the enclosure and the environment to slowly equalize the pressure inside and outside the enclosure at rest. These openings are most preferably placed at the center of a receptacle.

The enclosure generally has a volume of about 100 to 1000 cubic centimeters (cm3), preferably about 200 to 800 cm3 and most preferably about 400 to 600 cm3. As the size of the enclosure decreases, the number of receptacles (and projectiles) decreases. As the size of the enclosure increases, the weight of the enclosure increases and the possibility of harm to people or property increases.

The number and distribution of receptacles is a matter of choice. It is generally preferable to include as many receptacles as the size of the enclosure allows. As the number of receptacles increases, the number of projectiles that can be propelled upon activation increases as well. The number of receptacles is generally about four to twenty, and is preferably about twelve to sixteen. The receptacles are preferably spaced equally about the enclosure to provide an omnidirectional flight of projectiles. For example, if the enclosure contains two receptacles, it is preferred that each receptacle is completely in a different hemisphere. If the enclosure has 3 projectiles, it is preferred that they are placed around the circumference 120 degrees apart, forming an equilateral triangle. If the enclosure has four receptacles, it is preferred that the receptacles form a tetrahedron. If the enclosure has 12 receptacles, it is preferred that the receptacles form a dodecahedron. Not every number of receptacles has a geometric solution for a perfectly even distribution, but preferred arrangements will give about the same distance between each receptacle in all directions. The receptacles are also preferably placed away from the joining surfaces used to assemble the enclosure.

The size and shape of the receptacles is depends on the size of the projectiles. The receptacles are sufficiently flexible to move from the retracted position to the extended position. The receptacles are also sized to hold the projectiles in a press fit without the need for clips or the like. If desired, the receptacles are made of a material that is different than non-receptacle body portions of the enclosure. If so, the material is flexible and durable, but elasticity is not required.

The structure of the enclosure is discussed in further detail in the following section on manufacturing.

3. The Projectiles

The projectiles 150 are objects that are pressed (inserted) into the receptacles of the enclosure and that are propelled when the grenade is actuated. The projectiles are preferably soft and are most preferably foam or rubber spheres. The projectiles are preferably spherical. The projectiles are generally about 5 to 40 millimeters (mm) in diameter and are preferably about 10 to 30 mm in diameter. The size of the projectiles and the size of the receptacles in the enclosure are dependent on each other in that the projectiles are held in place in the receptacles by the inner walls of the receptacle pressing against the projectiles. Suitable projectiles are widely available commercially for use with NERF RIVAL guns and similar products.

4. Use

The use of the preferred embodiment of the toy grenade of this invention can now be considered. The receptacles of the enclosure are moved to their retracted positions, if not already in their retracted positions. Projectiles are then pressed into a plurality of the receptacles. When the user wishes to have the projectiles propelled from a location, the user throws the toy grenade to the desired location. When the toy grenade contacts the ground, a wall, or other hard surface 500 with sufficient velocity, the enclosure is sufficiently compressed, as best seen in FIGS. 6 and 7, to move the receptacles towards their extended position and to propel the projectiles. The term “hard surface” is used herein to mean a surface with sufficient resistance to cause sufficient compression in the enclosure to propel the projectiles. Carpeted flooring, mowed grass, and people all provide sufficient resistance to be considered a hard surface. The distance the projectiles are propelled depends on many factors, including the velocity upon impact and the orientation of the toy grenade (and its receptacles) upon impact. Receptacles contacting the hard surface will generally not extend to propel their projectiles. Projectiles propelled toward the hard surface will, of course, quickly hit the hard surface and ricochet or stop on contact depending on the surface. Projectiles facing away from the hard surface will travel at various directions and at various distances.

5. Alternate Embodiments

A variety of alternate embodiments are suitable. Referring to FIGS. 8 to 12, a second embodiment 200 of the toy grenade has a balloon (also known as a bladder) 230 that communicates with the enclosure 210 via a twistable conduit 235 and enables the 5 propulsion of the projectiles to be based on time rather than on contact with a hard surface. The balloon and the conduit are preferably made of thinner material than the non-receptacle portion of the enclosure so they are able to, respectively, expand and twist. More particularly, the balloon generally has a wall thickness of about 1 to 4 mm and the conduit preferably has a thickness of about 3 to 8 mm.

In FIG. 8, the enclosure, balloon, and conduit are all at atmospheric pressure. In FIG. 9, the enclosure is squeezed to force fluid through the conduit into the balloon. In FIGS. 10 and 11, the conduit is twisted multiple times to seal the superatmospheric pressure fluid in the balloon, as can be seen in the increased volume of the balloon. The enclosure is then loaded with projectiles while maintaining the twisted configuration of the conduit. The toy grenade is then ready for use as shown in FIG. 12. When the toy grenade is thrown, the conduit untwists to allow fluid to quickly move back into the enclosure. This movement of air moves the receptacles to their extended position and propels the projectiles as shown in FIG. 13. The time to untwist and fire the projectiles is generally about one-half to five seconds. The delay enables a user to throw or launch the toy grenade and to have it propel the projectiles while in midair, rather than waiting for the toy grenade to contact a hard surface.

Referring now to FIG. 14, a third embodiment 300 of the toy grenade has a tail 340 that causes the enclosure to be in a specific orientation when it is thrown. If desired, the receptacles are placed in specific locations to propel the projectiles in non-random directions. For example, in the embodiment shown, all the receptacles are in the same hemisphere as the tail. This has the effect of propelling all of the loaded projectiles, without any being directed at the impact surface. This prevents the user from needing to load more receptacles than can actuate on an impact. Referring to FIG. 15, a fourth embodiment 400 is similar to the third embodiment with the exception that it has a cylindrical bellows extension 445 to the enclosure at the site of most likely impact.

Other embodiments (not shown) are actuated by a conventional timer, remote control, or other electronic trigger using an air pressure vessel or piston mechanism to provide fluid pressure on command. The electronic trigger is activated by any suitable means, including remote control, timer, sound or vibration sensor, flex sensor, or light sensor.

The non-impact activation embodiments of the toy grenade generally require non-soft components and thus are not as suitable for throwing around or at people. Locating the non-elastomeric components inside softer materials reduces the risks, whether or not the toy is intended to be thrown.

While many embodiments have a roughly uniform distribution of projectiles, the receptacles may also be distributed for a directional effect. Directional explosions can be simulated by a spherical section roughly equal in angular size to the desired distribution of projectiles. Such a device might be set as a trap to fire laterally, triggered by the user directly or by a sensor signal, roughly simulating the action of a Claymore mine. A toy simulating a more traditional landmine might instead be set to fire upwards and be activated by the impact of being stepped on. A toy which activates while fixed to, sliding, or rolling on a surface might have a roughly hemispherical distribution to send projectiles in all directions other than into that surface. Such a hemispherical distribution might be used with a remote control or passively rolling ground vehicle, allowing the toy to be propelled towards its target without being thrown. Appropriate suspension or flexible chassis should be used with such a toy such that it bottoms out and does not roll when overloaded to avoid slipping incidents. A toy with a roughly circular distribution could be intended to send projectiles in all directions on a plane parallel to the ground, perhaps with an upward tilt to optimize for the expected ballistic trajectory and target height.

For some toys (in particular stationary toys simulating a remote bomb or mine), it may be a desirable feature for the toy to activate when shot with a toy gun or bumped by a player. A microphone mounted inside the elastomeric manifold is very sensitive to the sound of the manifold being hit, and could be used with a simple sound volume threshold to activate. Alternately, a mechanical switch or sensor in the spheroid superstructure could detect a very small bend in the material indicating similar conditions. Either method could emulate the popular movie and videogame trope of explosives being set off by gunfire.

6. Manufacturing

The toy grenade of this invention is typically manufactured by casting in parts or by three-dimensional (3D) printing (also known as additive manufacturing) using an elastomeric material. A suitable casting process for manufacturing the preferred embodiment of the toy grenade of this invention with the receptacles in the inward position is shown in FIGS. 16 to 36.

Referring first to FIGS. 16 to 18, the first step is to create an exterior positive mold 600 from a rigid material such as plastic or metal. The exterior positive will have the same outer shape as the cast hemisphere. The next step is to provide an inwardly angled container 610. A quantity of a gelatin material sold under the trademark COMPOSIMOLD by ComposiMold of Manchester, Maine is then poured into the container. The choice of molding material (Composimold) must be flexible to allow the product to be extracted from the mold non-destructively. The exterior positive mold is then inserted. To control the position of the casting, a container with slots or other locating mechanism is used. The gelatin material solidifies to form an exterior negative mold 620 as shown in FIGS. 19 to 21.

Referring now to FIGS. 22 to 24, the next step is to create an interior negative mold 630 from a rigid material using conventional methods. The interior negative mold is then positioned in the recess of the exterior negative mold created in the previous step. The assembled pair is then placed into the same inwardly angled container 610. A liquid silicone rubber is then injected into the void 650 between the two molds. The silicone rubber solidifies to form a hemispheroid 660.

Referring now to FIGS. 25 to 27, the hemispheroid is removed from the mold. The body shown contains a ridge around the circumference of its open face.

Referring now to FIGS. 28 to 30, the hemispheroid is trimmed to produce a finished part having a ridge. A similar process is used to produce a finished part that has a mating groove around the circumference of its open face. The hemispheroids are then fused together with uncured silicone rubber to produce the complete enclosure.

Care is taken to choose an optimal amount of fluid inside the grenade before it is sealed. Too much fluid makes the grenade impossible to load. Too little fluid makes the grenade more difficult to activate on impact. For air and other gases, changes in ambient 10 temperature and pressure change the optimal amount of fluid. For example, a grenade filled on a cold day may become overinflated on a hot day and vice versa. If desired, a small hole is added to allow users to squeeze out extra air.

If desired, the physical characteristics of the enclosure are modified by incorporating other materials that resist stretching or bending into the spheroidal structure.

If desired, the hemispheroids are cast with the receptacles extending outwardly. The process for casting the toy in the extended position is the same, but using a mold system like that shown in FIGS. 31-33. The resulting hemisphere will have the shape shown in FIGS. 34-36 at rest, but the receptacles should be pushed into the retracted position before assembly. The elasticity of receptacles cast in the extended position can potentially launch the projectiles slightly faster, but the resulting toy grenade tends to be less stable and more difficult to load completely. When the receptacles are cast in the retracted position, the elasticity slightly impedes launching the projectiles, but the toy grenade tends to be more stable and has a stronger tendency to automatically reset its pockets. The difference in loadability is especially noticeable if the toy grenade is made to have a small leak. A small leak is often desirable if the toy is air-filled and expected to operate at a different pressures than the conditions under which it was made. Receptacles being cast in the retracted position is generally preferred, as the difference in projectile launch speed is very small with such a thin, soft material.

7. Advantages

The toy grenade of this invention has many advantages. The toy grenade is entirely soft, and similar in softness to the rubber and foam projectiles widely used by toy blasters. The soft toy grenade minimizes harm to people and property to a degree not possible with a non-soft or partially soft mechanism. The preferred embodiment of the toy grenade is actuated by throwing it against a hard surface so there is no need for the person throwing to remove a pin or depress a foot pump or take any other action. The projectiles are propelled in multiple directions and at varying distances and thus simulate the movement of projectiles from grenades.

The toy grenade is easy to manufacture and is easy to use. The toy grenade is also reusable without any need to replace or recharge components.

Claims

1. A toy grenade comprising: (a) an enclosure having a substantially sealed interior containing a fluid, the enclosure having a plurality of receptacles, each receptacle having a retracted position and an extended position, each receptacle movable from the retracted position to the extended position upon sufficient compression of the fluid by impact of the enclosure with a hard surface; and(b) a plurality of projectiles held in some or all of the retracted receptacles by press fit and being suitable for propulsion from the enclosure in multiple directions when the receptacles move from the retracted position to the extended position.

2. The toy grenade of claim 1 wherein the enclosure is generally spherical.

3. The toy grenade of claim 1 wherein the enclosure is made of an elastomeric material

4. The toy grenade of claim 1 additionally comprising a balloon communicating with the interior of the enclosure through a twistable tubular conduit.

5. The toy grenade of claim 1 additionally comprising a tail extending from the enclosure.

6. The toy grenade of claim 1 wherein the enclosure has non-receptacle body portions with a wall thickness of about 8 to 14 millimeters and has receptacles with a wall thickness of about 0.5 to 4 millimeters.

7. The toy grenade of claim 1 wherein the receptacles are in their retracted position at elastic rest.

8. A toy grenade for propelling projectiles in multiple directions, the toy grenade comprising an enclosure having a substantially sealed interior containing a fluid, the enclosure having a plurality of receptacles for receiving projectiles, each receptacle having a retracted position and an extended position, each receptacle movable from the retracted position to the extended position to propel the projectile upon sufficient compression of the fluid by impact of the enclosure with a hard surface.

9. The toy grenade of claim 8 wherein the enclosure is generally spherical.

10. The toy grenade of claim 8 wherein the enclosure is made of an elastomeric material.

11. The toy grenade of claim 8 additionally comprising a balloon communicating with the interior of the enclosure through a twistable tubular conduit.

12. The toy grenade of claim 8 additionally comprising a tail extending from the enclosure.

13. The toy grenade of claim 8 wherein the enclosure has non-receptacle body portions with a wall thickness of about of about 8 to 14 millimeters and has receptacles with a wall thickness of about 1 to 5 millimeters.

14. The toy grenade of claim 5 wherein the receptacles are in their retracted position at elastic rest.

15. A method for safely simulating an exploding grenade while playing, the method comprising: (a) providing an enclosure having a substantially sealed interior containing a fluid, the enclosure having a plurality of receptacles, each receptacle having a retracted position and an extended position, each receptacle movable from the retracted position to the extended position upon sufficient compression of the fluid by impact of the enclosure with a hard surface;(b) placing a projectile in each of a plurality of the retracted receptacles; and(c) throwing the enclosure against a hard surface with sufficient velocity to compress the fluid sufficiently to move the receptacles from the retracted position to the extended position and to thereby propel the projectiles in multiple directions.

16. The method of claim 15 wherein the enclosure is generally spherical.

17. The method of claim 15 wherein the enclosure is made of an elastomeric material.

18. The method of claim 15 wherein the enclosure additionally comprises a balloon communicating with the interior of the enclosure through a twistable tubular conduit.

19. The method of claim 15 wherein the enclosure additionally comprises a tail extending from the enclosure.

20. The method of claim 15 wherein the enclosure has non-receptacle body portions with a wall thickness of about of about 8 to 14 millimeters and has receptacles with a wall thickness of about 0.5 to 4 millimeters.