A pedestrian warning device, comprising a warning device body having a cavity and an open end portion, and a sound-generating device mounted inside the cavity, wherein the pedestrian warning device further comprises a grille cover arranged on the end portion of the warning device body; the grille cover comprises at least two grille layers spaced at intervals from the inside to the outside, each of the grille layers comprising a plurality of crossbeams, the crossbeams being arranged at intervals so as to form gaps to enable gas to flow between adjacent crossbeams, and wherein a width of the gaps is not greater than a width of the crossbeams, and the crossbeams of adjacent grille layers are interleaved with each other. The grille cover can protect internal component of the pedestrian warning device and will not affect the performance of the pedestrian warning device.

A game call includes a first resonant member. A second resonant member is telescopically operable within the first resonant member between a plurality of telescopic positions. A harmonic carriage has a body and a reed assembly. The harmonic carriage is slidably operable within the second resonant member. The first and second resonant members and the harmonic carriage are slidably operable relative to one another to adjust a resonant length defined between the reed assembly and a resonating end of the first resonant member.

A game call includes a first resonant member. A second resonant member is telescopically operable within the first resonant member between a plurality of telescopic positions. A harmonic carriage has a body and a reed assembly. The harmonic carriage is slidably operable within the second resonant member. The first and second resonant members and the harmonic carriage are slidably operable relative to one another to adjust a resonant length defined between the reed assembly and a resonating end of the first resonant member.

The invention is a single piece molded toy that is shaped like an animal wherein the center of the toy is in the shape of and accordion and a squeaker in the head portion makes sound when the toy is squeezed, and as the toy returns to its original state a grunter located in the rear of the toy makes a grunting sound similar to that of a pig.

A sound producing device includes at least one air pulse generating element. Each of the at least one air pulse generating element includes a membrane, a first air chamber and at least one opening, wherein a chamber pressure exists in the first air chamber, and the opening is connected between the first air chamber and an ambient surrounding the sound producing device. The membrane is actuated to change the chamber pressure of the first air chamber to generate a plurality of air pulses, the air pulses are propagated through the at least one opening, the air pulses produce a non-zero offset in terms of sound pressure level, and the non-zero offset is a deviation from a pressure value of an ambient pressure outside the sound producing device.

A sound producing device includes at least one air pulse generating element. Each of the at least one air pulse generating element includes a membrane, a first air chamber and at least one opening, wherein a chamber pressure exists in the first air chamber, and the opening is connected between the first air chamber and an ambient surrounding the sound producing device. The membrane is actuated to change the chamber pressure of the first air chamber to generate a plurality of air pulses, the air pulses are propagated through the at least one opening, the air pulses produce a non-zero offset in terms of sound pressure level, and the non-zero offset is a deviation from a pressure value of an ambient pressure outside the sound producing device.

A sound producing device includes at least one air pulse generating element. Each of the at least one air pulse generating element includes a membrane, a first air chamber and at least one opening, wherein a chamber pressure exists in the first air chamber. The membrane is actuated to change the chamber pressure of the first air chamber to generate a plurality of air pulses, the air pulses are propagated through the at least one opening, the air pulses produce a non-zero offset in terms of sound pressure level, and the non-zero offset is a deviation from a pressure value of an ambient pressure outside the sound producing device. Each pulse cycle has a pulse-generating time segment and a pulse-isolating time segment, the driving signal during the pulse-generating time segment is different from the driving signal during the pulse-isolating time segment.

A sound producing device includes: a housing and carriage. The housing has a cylindrical interior surface with a helical tracking thread protruding therefrom. The cylindrical carriage has an opening in its exterior surface defining a helical shaped recess that receives and tracks along the helical housing thread. A squeaker may be secured within the carriage, so when air flows in a first direction through the housing, it emits sound, and the squeaker carriage is driven to track along the helical thread, causing the carriage to rotate and also translate in the first direction, according to a pitch of the helical thread. A frequency of the sound produced by the squeaker changes according to the carriage's translational movement, as it changes the dimensions of the sound-producing chamber. When air subsequently flows through the housing in the opposite direction, the carriage's motion is reversed, correspondingly changing the frequency of sound produced.

The invention is a single piece molded toy that is shaped like an animal wherein the center of the toy is in the shape of and accordion and a squeaker in the head portion makes sound when the toy is squeezed, and as the toy returns to its original state a grunter located in the rear of the toy makes a grunting sound similar to that of a pig.

A game call includes a first resonant member. A second resonant member is telescopically operable within the first resonant member between a plurality of telescopic positions. A harmonic carriage has a body and a reed assembly. The harmonic carriage is slidably operable within the second resonant member. The first and second resonant members and the harmonic carriage are slidably operable relative to one another to adjust a resonant length defined between the reed assembly and a resonating end of the first resonant member.