MXPA06002280A - Flying toy with extending wings - Google Patents

Abstract

A flying toy may comprise an elongate body extending along a body axis from a forward end to a rearward end. The flying toy may comprise a wing assembly, comprising a wing adapted to move relative to the body between an extended position in which at least a portion of the wing extends away from the body and a retracted position in which the wing portion is closer to the body. The flying toy may comprise an actuator movable along the body between a forward position and a rearward position. One of the wing assembly and the actuator may comprise a contact element, and the other of the wing assembly and the actuator may comprise an elongate contact surface extending obliquely relative to the body axis. The contact element may move along the contact surface as the actuator moves between the rearward position and the forward position, thereby moving the wing between the retracted position and the extended position.

Description

FLYING TOY WITH WINGS THAT EXTEND This application claims the benefit of the provisional application of US patent Serial No. 60 / 685,166, filed on May 27, 2005. The complete description of the patent application identified above is incorporated herein by reference in its entirety for all purposes. FIELD OF THE INVENTION The present invention relates generally to flying toys and more particularly to toy gliders having extendable wings. Such flying toys can be launched with an elastic mechanism. BACKGROUND OF THE INVENTION Flying toys are well known, including toy gliders launched with an elastic mechanism, such as a rubber band. However, traditional toy gliders with fixed wings may offer less than optimal performance due to the drag imposed by the wing. Toy gliders have relatively large wings, which tend to create large amounts of lift. While the large amounts of lift produced by the wings of a glider may be desirable during the flight planning phase, the induced drag of such a wing can be problematic during the launch phase. When a toy glider is launched, such as by means of an elastic mechanism, the glider may experience a relatively high acceleration and may be driven upward at a relatively high speed. Initially, the glider can be accelerated by the tension in the elastic launch mechanism until the glider is free of the launch mechanism. Once free of the mechanism, the glider can be traveling at a speed greater than its optimal glide speed, such that the glider can rise due to wing lift or ballistic trajectory induced by the launching mechanism. The glider can continue to rise until it reaches its maximum altitude, at which point the glider can move to a flight glide mode in which the weight of the glider imparts enough forward speed for the wings to induce lift. However, the different conditions during the launch and glide phases of the flight may make it difficult to improve the performance of both the launch and the glide of a fixed configuration glider. For example, the launch performance can be improved if a toy glider has a relatively low drag, thereby allowing a greater height to be achieved. A toy glider can have a relatively low drag if a relatively small wing is used. In contrast, the performance of the glide can be improved if a toy glider produces a relatively large amount of lift, such as due to a relatively large wing. However, large wings tend to produce significant amounts of aerodynamic drag, which can be detrimental to launch performance. Unlike a glider with a fixed wing, a glider that has rotating or extendable wings can exhibit improved performance in both the launch and glide phases of the flight. In particular, when the wings are in a retracted position, the glider may have relatively low drag such that it may exhibit improved launch performance. In addition when the wings are in an extended position, the glider may have increased lift such that it may exhibit improved gliding performance.

Examples of toy gliders released with an elastic mechanism are described in US Patent Nos. 1,116,122, 1,190,343, 1,842,434, 1,920,746, 2,059,131, 2,078,374, 2,587,699, 3,369,319, 3,408,767, 3,654,729, 4,915,664, 5,299,966, 5,846,112, and 5,934,967. Examples of toy gliders that include automatically extending wings are described in U.S. Patent Nos. 1,116,122, 1,190,343, 1, 353,147, 1,842,434, 1,920,746, 2,059,131, 2,078,374, 2,306,866, 2,587,699, 2,765,582, 3,006,109, 3,369,319, 3,408,767, 3,380,189, 3,654,729, 3,839,818, 3,943,657, 4,915,664, 5,299,966, and 5,934,967. Examples of toy gliders that include wings that are retracted for release are described in U.S. Patent Nos. 3,369,319, 4,915,664, and 5,934,967. Examples of toy gliders that include automatically extending wings and a mechanism configured to retard or delay the extension of the wings are described in U.S. Pat. Nos. 2,306,866, 3,006,109, 3,380,189, 3,654,729, and 3,943,657. Examples of mechanisms for automatically extending the arms are described in US Patents Nos. 2,781,596, and 5,934,967. The descriptions of these and other publications referenced here are incorporated by reference in their entirety for all purposes. BRIEF DESCRIPTION OF THE INVENTION In one example, a flying toy may comprise an elongated body extending along an axis of the body with the body comprising a leading end and a trailing end. The flying toy may comprise a wing assembly, which comprises a wing adapted to move relative to the body between an extended position in which a wing portion extends away from the body and a retracted position in which the wing portion is closer to the body. The flying toy comprises an actuator that can move along the body between a front position and a rear position. One of the wing assembly and the actuator may comprise a contact element, and the other of the wing assembly and the actuator may comprise an elongate contact surface that extends obliquely relative to the axis of the body. The contact element can move along the contact surface when the actuator is moved between the rear position and the forward position, thereby moving the wing between the retracted position and the extended position. In one example, a flying toy may comprise an elongated body extending along a body axis from a forward end to a rearward end. The flying toy may comprise a wing assembly, which may comprise a wing adapted to rotate relative to the body between a retracted position in which at least a portion of the wing is close to the body and an extended position in which the portion of wing extends away from the body. The flying toy may comprise an actuator that can move along the body from a forward position to a rearward position. One of the wing assembly and the actuator may comprise a contact element, the other of the wing assembly and the actuator may comprise an elongate contact surface that extends obliquely relative to the axis of the body. The contact element can move along the contact surface as the actuator moves from the front position to the rear position. The movement of the contact element along the contact surface when the actuator is moved from the forward position to the rear position can allow the wing turning movement from the extended position to the retracted position. In one example, a flying toy may comprise an elongated body extending along a body axis, with the body comprising a leading end, and a trailing end. The flying toy may comprise a wing adapted to move relative to the body between a retracted position in which at least a portion of the wing is close to the body and an extended position in which the wing portion extends away from the body. The flying toy can comprise an actuator that can be moved along the body between a front position and a rear position. The flying toy may comprise a coupling assembly that couples the actuator to the wing. The coupling assembly can be configured to move the wing from the extended position to the retracted position when the actuator moves from the forward position to the rear position. The flying toy may comprise a delay assembly, wherein the delay assembly is configured to retard the movement of the actuator along the body. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a front perspective view of a flying toy embodiment with the wings shown in an extended position, with the retracted position indicated by dashed lines. Fig. 2 is a rear perspective view of the flying toy of Fig. 1. Fig. 3 is a perspective view of a launching device suitable for use with the flying toy of Fig. 1. Fig. 4 is a side view of the flying toy of Fig. 1. Fig. 5 is a longitudinal sectional view of the flying toy of Fig. 1, taken generally along line 5-5 of Fig. 1. Fig. 6 is a planar rear view of the flying toy of Fig. 1 with the fixed wings omitted, illustrating one embodiment of the wing extension mechanism with the wings shown in an extended position. Fig. 7 illustrates the extension mechanism of the wings of Fig. 6 with the wings shown in a retracted position.

Fig. 8 is a back plan view of the flying toy of Fig. 1, with the fixed wing omitted, illustrating another embodiment of a wing extension mechanism with the wings shown in an extended position and with a schematic representation of a delay assembly. Fig. 9 illustrates the extension mechanism of the wings of Fig. 8 with the wings shown in a retracted position.

Figs. 10 and 11 illustrate a pre-launch sequence for the flying toy of Fig. 1. Figs. 12 and 13 illustrate the launch and extension of the wings of the flying toy of Fig. 1. DESCRIPTION DETAIL OF THE INVENTION An illustrative example of a flying toy is shown generally at 20 in Figs. 1-2. The flying toy 20 may include a body 22, a wing assembly 24, and a wing extension mechanism 26. As shown in the illustrative embodiment presented in Fig. 1, the body 22 and the assembly 24 of the wing can be mutually configured such that the flying toy 20 is configured as a plane without a tail. The body 22 may be a generally elongated structure, which extends along a body axis 28 from a forward end 30 to a rearward end 32. The external surfaces of the body 22 can be configured in any suitable form such as to resemble a human figure, an animal, an aircraft fuselage, or the like. As shown in the illustrative embodiment presented in Fig. 1, when the body 22 is configured to look like a human figure, the front end 30 can be configured to resemble a head, and the rear end 32 can be configured to resemble the feet . In some embodiments, the body 22 can be configured to resemble a superhero, such as the BATMAN character, as shown in Fig. 1. BATMAN and all the characters and related elements are registered trademarks of and properties registered by DC Comics and they are used with authorization. The forward end 30 of the body 22 may include an elastic structure such as the nose member 34. The nose member 34 may include a hollow structure in general terms, such as one made of an elastomer. In the illustrative embodiment presented in Fig. 1, the nose member 34 is configured to resemble the head of a human figure. The wing assembly 24. it may include at least one wing 36. As shown in the illustrative embodiment presented in Fig. 1, the wing may include a first wing 38 and a second wing 40. Each of the first and second wings 38, 40 is can adapt to move relative to the body 22, such as from an extended position 44, in which at least a portion, such as the outer region 48 of the respective first and second wings 38, 40, extends away from the body 22, to a retracted position 42, in which the outer region 48 is closer to the body 22, as shown in Fig. 1. In some embodiments, each of the first and second wings 38, 40, may be biased towards position 44 extended. As shown in the illustrative embodiment presented in Fig. 1, the wing assembly 24 can be configured to resemble a layer, such as one worn by a superhero. As shown in the illustrative embodiment presented in Fig. 1, each of the first and second wings 38, 40, can be rotatably connected to the body 22 near the front end 30. When the first and second wings 38, 40 are rotatably or pivotally connected to the body 22, each of the first and second wings 38, 40 can rotate about a turning point 46 (not shown in FIG. 1) from the extended position 44 to the retracted position 42, in which an outer region 48 of the wing 36 may be close to the rear end 32, as shown in Fig. 1. As shown in the illustrative embodiment presented in FIG. Fig. 1, wing assembly 24 may include at least one fixed wing 50. The fixed wing 50 can be attached to the body 22 using any method of attachment sufficient to maintain the position of the fixed wing 50 relative to the body 22, such as mechanical fasteners and / or an adhesive. For example, as shown in Fig. 2, the fixed wing 50 can be attached to the body 22 using one or more wing fastening bolts 52. As shown in the illustrative embodiment presented in Fig. 2, the flying toy 20 can include at least one vertical stabilizer 54, which can be attached to the body 22 and / or the wing assembly 24. For example, as shown in Fig. 2, the vertical stabilizer 54 can be arranged generally on an upper surface 56 of the fixed wing 50. An illustrative embodiment of a launching device 58 suitable for use with the flying toy 20 is shown in Fig. 3. The launching device 58 may include a handle 60 and an elastic member 62 defining a loop 64. The handle 60 it can be configured to be held by a hand 66, as shown in Fig. 10. The flying toy 20 can be configured for launch with any suitable device, such as the launching device 58. As shown in the illustrative embodiment presented in Fig. 1, the flying toy 20 may include at least one launch hook 68 disposed in the body 22.

In Figs. 5-7, a portion of an illustrative example of the flying toy 20 is shown with an illustrative embodiment of the wing extension mechanism 26. The wing extension mechanism 26 may include an actuator 70 and at least one wing support arm 72. The actuator 70 can be configured to move along the body 22, such as along a path generally parallel to the body axis 28, from a forward position 74, as shown in Fig. 6, to a rear position 76, as shown in Fig. 7. The actuator 70 may include a region 78 flattened in general terms, such as the one proximal to its trailing end, which may be designated as a launch handle 80. The launch handle 80 can be adapted to be held by a hand, such as between the thumb and the finger, as shown in Figs. 10 and 11. For example, as shown in Fig. 5, a launch handle 80 can include a plurality of edges 82, which can be configured to improve grip of the launch handle 80. By moving the launch handle 80 relative to the 22 from a forward position 84 to a rearward position 86, as shown in Fig. 1, you can move the actuator 70 from the forward position 74, as shown in Fig. 6, to the back position 76, as shown in Fig. 7.

The actuator 70 may be biased to the forward position 74 in some embodiments. As shown in the illustrative embodiment presented in Figs. 5-7, the actuator 70 may be connected to the body 22 with an elastic member, such as the extension spring 88, which may tend to deflect the actuator 70 towards the forward position 74. In some embodiments, the spring 88 may be a compression spring such that the actuator 70 may be biased toward the rearward position 76. In some embodiments of the wing extension mechanism 26, the movement of the actuator 70 along the body 22 can be delayed, for example by a delay assembly (not shown in Figs 7 and 8). "The delay assembly may include any suitable mechanism for delaying the movement of the actuator 70 along the body 22. Exemplary non-exclusive challenge mechanisms may include friction, such as could occur due to close tolerances and / or a layer of grease or other material between the actuator 70 and the body 22 or the aerodynamic drag, such as due to a vane driven by differential pinion rotated by a rack on the actuator 70 or the body 22. In some embodiments, the delay assembly may retard movement of the actuator 70 along the body 22. An exemplary non-limiting delay mechanism may include a suction cup (not shown) disposed in one of the actuator 70 and the body 22, wherein the suction cup is configured to adhere to the other of the actuator 70 and the body 22 for a period of delay prior to the movement of the actuator 70 along the body 22. As shown in the illust mode rativa presented in Figs. 6 and 7, the wing 36 can be attached to the wing support arm 72 such that the wing support arm 72 and the wing 36 can be configured to move relative to the body 22 such as between a retracted position 42 and a position 44 extended. The wing 36 can be attached to the wing support arm 72 using an adhesive and / or a mechanical fastener, such as one or more wing fastening bolts 52, as shown in Figs. 6 and 7. The wing support arm 72 can be rotatably attached to the body 22, such as at the pivot point 46, as shown in the illustrative embodiment presented in Figs. 6 and 7. The wing support arm 72 and the wing 36 can rotate relative to the body 22 between the extended position 44, as shown in Fig. 6 and the position 42 retracted as shown in Fig. 7. The wing extension mechanism 26 may include at least one contact surface 90, and at least one contact element 92. As shown in the illustrative embodiment presented in Figs. 6 and 7, the contact surface 90 can be arranged on the actuator 70, and the contact element 92 can be arranged on the wing 36, such as on the wing support arm 72. In some embodiments, the contact surface 90 can be disposed in the wing 36 and the contact element 92 can be arranged in the actuator 70.

The contact surface 90 can extend obliquely relative to the axis 28 of the body as shown in Figs. 6 and 7. The relative angle between the contact surface 90 and the body axis 28 can be any suitable angle between zero (0) and ninety (90) degrees, including an angle between thirty (30) degrees and sixty (60) degrees, such as approximately forty-five (45) degrees. Although the contact surface 90 has an angle to the rear end 32 in the illustrative embodiment presented in Figs. 6 and 7, the contact surface 90 could have an angle toward the front end 30 in some embodiments. The contact element 92 can be configured to engage with the contact surface 90, as shown in Figs. 6 and 7. As shown in the illustrative embodiment presented in Figs. 6 and 7, the contact element 92 can be arranged on the wing support arm 72. As can be seen in Figs. 6 and 7, the contact element 92 can be configured to move relative to the contact surface 90, such as by sliding along the contact surface 90, when the actuator 70 moves from the forward position 74 to the position 76 later. In the illustrative embodiment presented in Figs. 6 and 7, the contact element 92 can slide inwardly along the contact surface 90 when the actuator 70 moves from the forward position 74 to the 76, such that the wing 36 moves from the extended position 44 towards position 42 retracted. When the actuator 70 moves from the rear position 76 to the forward position 74, the 02 can slide outwardly along the contact surface 90, such that the wing 63 moves from the retracted position 42 to the position 44 extended. As used herein, contact element 92 refers to the wing portion 36 or the wing support arm 72 that engages the contact surface 90. In itself, the contact element 92 is not limited to any particular structure or form. Instead, the wing 36 or the wing support arm 72 need only include some structure or structure configured to engage with the contact surface 90. As shown in the illustrative embodiment presented in Figs. 6 and 6, the contact element 92 can at least partially include the combination of two surfaces 94, 96. In particular, the contact element 92 can at least partially include the rounded or angular transition between the two intersecting surfaces such as the surfaces 94, 96. The wing 36 and the wing support arm 72 can be biased toward the retracted position 42 in some embodiments. As shown in the illustrative embodiment presented in Figs. 6 and 7, the wing support arm 72 can be connected to the body 22 with an elastic element, such as the extension spring 98, which can tend to deflect the wing support arm 72 and the wing 36 towards the position 42 retracted. In the illustrative embodiment presented in Figs. 6 and 7, the wing 36 and the wing support arm 72 are biased toward the retracted position 42 and the actuator 70 is biased towards the front position 74. The deflection of the wing 36 towards the retracted position 42 can react against the deflection of the actuator 70 towards the forward position 74 such that the contact element 92 can be maintained against the contact surface 90, as shown in the illustrative embodiment presented in FIGS. Figs. 6 and 7. When the wing 36 and the wing support arm 72 are biased towards the retracted position 42 and the actuator 70 is deflected to the forward position 74, the deflection of the 1 actuator 70 may be relatively greater than the deflection of the wing. 36 and the wing support arm 72 such that the wing 36 effectively deviates toward the extended position 44. The contact element 92, the contact surface 90, and the springs 88 and 98, which can maintain the contact element 92 against the contact surface 90, can collectively define a coupling assembly 100. As shown in the alternative embodiment presented in Figs. 6 and 7, the coupling assembly 100 can couple the actuator 70 to the wing 36, such that the coupling assembly 100 can move the 36 from the extended position 44 to the retracted position 42 when the actuator 70 moves from the forward 74 position. to position 76 later.

In Figs. 8 and 9, a portion of an illustrative example of a flying toy 20 is shown, with another embodiment illustrating a wing extension mechanism 102. Unless otherwise specified, the wing extension mechanism 102 may contain the same structure, functionality, and variations as the wing extension mechanism 26 previously described. The wing extension mechanism 102 may include one or more arms 104. A first end of the arm 104 may be rotatably connected to the wing support arm 72 and a second end of the arm 104 may be rotatably connected to the actuator 70. , as shown in Figs. 8 and 9. The 104 can define a coupling assembly 106, such that the coupling assembly 106 can move the wing support arm 72 and the wing 36 from the extended position 44 to the retracted position 42 when the actuator 70 moves. from the forward position 74 to the wing support arm 72, as shown in Figs. 8 and 9. The wing extension mechanism 102 may include a delay assembly, which is illustrated schematically at 108 in Figs. 8 and 9. The delay assembly 108 may include any of the delay mechanisms discussed above in connection with the wing extension mechanism 26. A launching functionality for an illustrative embodiment of the flying toy 20 can be explained with reference to Figs. 10-13. As shown in FIG. 10, the handle 60 of the launching device 58 can be gripped in a first hand 66 and the loop 64 can be hooked with a launch hook 68, the second hand 110 can hold the launch handle 80 and move the flying toy 20 away of the first hand 66 and the launching device 58 as indicated by the arrow 112, such that the loop 64 of the elastic member 62 is put into tension. The opposing forces respectively imparted by the loop 64 on the launch hook 68 and by the second hand 110 on the launch handle 80 can cause the 70 to move to the rear position 76. As shown in Fig. 11, the movement of the launch handle 80 towards the rear position 86, as indicated by the arrow 114, which corresponds to the movement of the 70, as indicated by the arrow 114, which corresponds to the movement of the actuator 70 from the forward position 74 to the rear position 76, can cause the first and second wings 38, 40 to move from the extended position 44 to the retracted position 42, as indicated by the arrow 116. When the second hand 110 releases the launch handle 80, the force imparted by the elastic member 62 on the launch hook 68, can launch the flying toy 20, as shown in Fig. 12. When the second hand 110 releases the handle 80 When the starter is released, the actuator 70 can be moved to the forward position 74, such as in response to a forward deflection on the actuator 70, which can cause the first and second wings to move from the forward position. n 42 retracted to the extended position 44, as indicated by arrow 118. It is believed that the description set forth above encompasses multiple distinct inventions with independent utility. While each of these inventions has been described in its preferred form, the specific embodiments thereof as discussed and illustrated herein, should not be considered in a limiting sense since numerous variations are possible. The material object of the invention includes all the novel and non-obvious combinations and sub-combinations of the various elements, characteristics, functions and / or properties described herein. Similarly, when any claim mentions "a", "a first" element or the equivalent thereof, such a claim must be understood to include the incorporation of one or more such elements, nor does it require not excluding two or more such elements. It is believed that the following claims point out in particular certain combinations and subcombinations that address one of the described inventions and are novel and not obvious. Inventions incorporated in other combinations and sub-combinations of characteristics, functions, elements and / or properties, can be claimed through amendments to the present claims or the presentation of new claims in this or a related application. Such amended or new claims, whether directed to a different invention or directed to the same invention, whether different, broader, narrower or equal in scope to the original claims, are also considered as included within the subject material of the inventions of the present invention.

Claims (20)

1. CLAIMS 1. A flying toy, characterized in that it comprises: an elongated body extending along an axis of the body, the body comprising a front end and a rear end; a wing assembly, comprising a wing adapted to move relative to the body between an extended position in which at least a portion of the wing extends away from the body and a retracted position in which the wing portion is closer to the body; an actuator that can be moved along the body between a forward position and a posterior position; and one of the wing assembly and the actuator comprising a contact element, and the other of the wing assembly and the actuator comprising an elongated contact surface extending obliquely relative to the body axis, the contact element that is moves along the contact surface when the actuator moves between the rear position and the forward position, thereby moving the wing between the retracted position and the extended position. The flying toy of claim 1, characterized in that the wing is biased towards one of the extended position and the retracted position. 3. The flying toy of claim 1, characterized in that the actuator is biased towards one of the front position and the rear position. The flying toy of claim 1, characterized in that the wing is rotatably connected to the body, near the front end. 5. The flying toy of claim 1, characterized in that the body is configured to resemble a human figure. The flying toy of claim 5, characterized in that at least a portion of the wing assembly is configured to resemble a layer. The flying toy of claim 1, characterized in that it comprises a vertical stabilizer arranged on the wing assembly. 8. The flying toy of claim 1, characterized in that it comprises a delay assembly, the delay assembly configured to retard the movement of the actuator along the body. 9. A flying toy, characterized in that it comprises: an elongate body extending along a body axis from a front end to a rear end; a wing assembly, comprising a wing adapted to rotate relative to the body between a retracted position in which at least a portion of the wing is close to the body and an extended position in which the wing portion extends away from the body; a movable actuator along the body from a forward position to a rearward position; and one of the wing assembly and the actuator comprising a contact element, and the other wing assembly and the actuator comprising an elongated contact surface extending obliquely relative to the body axis, the contact element that is moves along the contact surface when the actuator moves from the forward position to the rearward position, the movement of the contact element along the contact surface when the actuator moves from the forward position to the rearward position allowing the wing turning movement from the extended position towards the retracted position. 10. The flying toy of claim 9, characterized in that the wing is deflected towards the extended position. The flying toy of claim 9, characterized in that: the wing is deflected towards the retracted position; and the actuator is deflected towards the forward position, the forward deflection of the actuator is sufficient to overcome the deflection of the wing towards the retracted position, thereby moving the wing between the retracted position and the extended position. The flying toy of claim 9, characterized in that the wing portion is near the rear end when the wing is in the retracted position. 13. The flying toy of claim 9. characterized in that the body is configured to resemble a human figure. 14. The flying toy of claim 13, characterized in that at least a portion of the wing assembly is configured to resemble a layer. 15. The flying toy of claim 9, characterized in that it comprises a delay assembly, the delay assembly configured to retard the movement of the actuator along the body. 16. A flying toy, characterized in that it comprises: an elongate body extending along a body axis, the body comprising a front end and a rear end; a wing adapted to move relative to the body between a retracted position in which at least one wing portion is close to the body and an extended position in which the wing portion extends away from the body; a movable actuator along the body between a front position and a rear position; a coupling assembly that couples the actuator to the wing, the coupling assembly that is configured to move the wing from the extended position to the retracted position when the actuator moves from the forward position to the rearward position; and a delay assembly, the delay assembly configured to retard the movement of the actuator along the body. The flying toy of claim 16, characterized in that the coupling assembly comprises: an elongate contact surface extending obliquely relative to the body axis, the contact surface disposed on one of the wing assembly and the actuator; and a contact element disposed on the other of the wing assembly and the actuator, the contact element moving along the contact surface when the actuator moves between the rear position and the forward position, thereby moving the wing between the retracted position and the extended position. 18. The flying toy of claim 16, characterized in that the wing deflects toward one of the extended position and the retracted position. 19. The flying toy of claim 16, characterized in that the actuator is biased toward one of the forward position and the rearward position. 20. The flying toy of claim 16, characterized in that the body is configured to resemble a human figure, and at least a portion of the wing assembly is configured to resemble a layer.