referring to fig1 , a preferred embodiment of the hearing protection device is shown in the “ closed ” or substantial hearing protection and sound attenuation position . the ear plug includes a base plug 2 and a second plug 4 . the base plug 2 includes at least a portion 6 that is resilient foam or a similar material . ideally , the outer portions of ear plug components 2 , 4 , and 6 , are all made of a resilient foam . the foam should be easily compressible by hand and should return to its original dimensions ( or exert pressure against the ear canal of the user ) when released . suitable foams are well - known in the art . the internal structure of the earplug , described in more detail below , is located in the innerspace of base plug 2 as shown as 14 in fig1 . alternatively , the internal structure could be located primarily within second plug 4 . ideally the diameter of the innerspace , 14 ( and the internal components within that space as described below ) are small relative to the overall diameter of the earplug and do not interfere with the compression , insertion and expansion of the ear plug . foam portion 6 of base plug 2 should be more substantially resilient since , as described in more detail below , this is a portion that must seal against second plug 4 in the closed position to insure substantial hearing protection and sound attenuation . as shown in fig1 , base plug 2 is first inserted into the ear of the user and second plug 4 and foam portion 6 would protrude outside of the ear canal of the user . in this embodiment the innerspace 14 is disposed within base plug 2 and foam portion 6 . sound channels 7 are located within base plug 2 and provide open space between innerspace 14 and the outside of the earplug . at the end of the innerspace closest to the ear drum of a user , compressible spring means 8 provides pressure to cause proper functioning of the internal mechanism described below . spring means 8 could be made of a suitable foam that exerts suitable force as it attempts to return to its original dimensions , or it could be a spring or other structure exerting a suitable biasing force . in a preferred embodiment , the spring means 8 is a foam material that expands and contracts within a sleeve 9 . sleeve 9 is desirable because of the friction between spring means 8 and the foam of base plug 2 . sleeve 9 should be made of a suitable plastic or metal such that a small coefficient of friction exists between sleeve 9 and spring means 8 . a cap , 10 , is permanently attached to the top surface of base plug 2 ( the surface nearest the ear drum of the user ) to hold spring means 8 and sleeve 9 in position . it will be seen that an open passage exists through base plug 2 and foam portion 6 , including passage through sound channels 7 . fig2 shows the hearing protection device of the present invention in the “ open ” or relatively obstructed position . as shown in this figure , second plug 4 has been displaced such that a space exists between second plug 4 and foam portion 6 . in this position sound enters in spaces 13 within the internal structure described in more detail below , passes through innerspace 14 and through sound channels 7 to reach the ear canal of the user . in this position spring means 8 has expanded from its compressed position in fig1 , thus providing a biasing force to displace second plug 4 into the open position . foam portion 6 has also expanded to its largest possible dimensions , thus permitting the gap to exist between it and second plug 4 . fig3 shows in more detail the inner mechanism of the present hearing protection device . in most general terms , this mechanism functions to change the location of second plug 4 and change the position of the present invention from the open to closed position , and vice versa . in this embodiment the position change occurs based on pressure applied against second plug 4 ( pressing the earplug in the direction of the ear of the user thereby insuring that the ear plug remains in place in the ear ). while the embodiment shown is a preferred one , other structures are possible to accomplish the same objectives and are well - known in the art . some of the structure shown in fig3 is also known in the art and has been used in such applications as ballpoint pens . returning to fig3 , portions of the hearing protection device described previously are again shown , including base plug 2 , second plug 4 , foam portion 6 , spring means 8 , sleeve 9 , sound channels 7 , and the spaces 13 . the key components of the internal structure shown in fig3 can be divided into primary three elements : ( i ) the switching sleeve shown in more detail in fig4 and comprising elements 16 and 18 , ( ii ) the switching ratchet shown in fig3 and 5 and comprising elements 13 , 40 , 42 , 44 , 46 , and 50 ; and ( iii ) the switching actuator shown in fig6 and comprising elements 30 , 32 , 34 , and 38 . the switching sleeve shown in fig4 is a cylinder , 16 , rigidly attached to the inner surface of the innerspace 14 within base plug 2 , and resting against ( but not rigidly attached to ) the inner surface of the innerspace within foam portion 6 and the innerspace 41 within second plug 4 . spaces 13 are disposed around the circumference of the switching sleeve cylinder , 16 , and permit sounds to pass through the switching sleeve . within the inner circumference of a cylinder 16 , a series of tabs , 18 , are spaced around that circumference and extend into the inside of the cylinder 16 . as described in more detail below , whether tabs 18 rests against ratchet tabs , 44 , determines the position of the device . the switching ratchet shown in fig5 is a rigid cylinder , 40 , having a series of ratchet tabs , 44 , disposed evenly around the outer circumference . teeth , 42 , that the top of the cylinder , 40 , extend around the top of the cylinder , and as described below , engage actuator teeth 38 on the switching actuator . cylinder 40 is rotatably attached to second plug 4 by pin 52 , such that when cylinder 40 is held in the “ closed ” position as a result of a ratchet tabs 44 resting against tabs 18 , second plug 4 is compressed against foam portion 6 and the device provides substantial hearing protection . alternatively , when cylinder 40 is in the “ open ” position and has been displaced by the force of spring means 8 up to the pointed it has contacted stops 50 located at the end of the switching sleeve furthest from foam portion 6 , space exists between foam portion 6 and second plug 4 permitting sounds to enter through spaces 13 . cylinder 40 is able to freely rotate , so that as the actuator teeth 38 on the switching actuator contact teeth 42 on the switching ratchet the cylinder 40 rotates ( thus changing the alignment between tabs 18 and ratchet tabs 44 ). fig6 shows the switching actuator 30 . the actuator is rigidly attached to spring means 8 . opposite spring means 8 is an actuator pin 34 , that extends into the circular space 46 within cylinder 40 . evenly spaced around the circumference of the actuator 30 are 4 fins , 32 , each of which have an actuator tooth , 38 , as shown . actuator tooth 38 engages the teeth 42 on the switching ratchet cylinder . in operation , when second plug 4 is depressed , teeth 42 engaged actuator teeth 38 , causing the cylinder 40 of the switching ratchet to rotate . after one depression the cylinder rotates to that tabs 18 engage ratchet tabs 44 and hold the second plug 4 into the closed position . after another depression of second plug 4 , the cylinder again rotates , but this time to a position that tabs 18 do not engage ratchet tabs 44 and the second plug 4 is extended to the full open position . the next depression again returns the second plug 4 to the closed position . fins 32 , tabs 18 , and ratchet tabs 44 are all configured to cause the device to function in this manner . in the open position , sound enters through spaces 13 , passes through the open spaces between and around the various internal components in innerspace 14 , and passes through sound channels 7 to enter the ear canal of the user . in the closed position , the compression of second plug 4 against foam portion 6 blocks most sound from reaching the innerspace of the ear plug and the ear canal of the user . other alternative structures are available to accomplish the objectives of this invention and afford the multiple position function of the present invention . ideally any force applied to any portion of the ear plug should not tend to pull the ear plug out of the ear canal . as an alternative to the inward force required in the preferred embodiment disclosed above , rotation of the second plug to release the second plug ( and / or lock it into the closed position ) would be acceptable . in this alternative embodiment biasing means would still be desirable to move the second plug from the closed position to the open position without the need for external force applied to the ear plug that could pull the ear plug out of the ear canal of the user . pressure against biasing means when moving the ear plug to the closed position is acceptable since it tends to force the ear plug into the ear canal of the user .
the present invention is a dual position hearing protection device . in one position , the device provides substantial sound attenuation and hearing protection . in the second position , an opening in the device permits sounds to enter the ear of the user relatively unobstructed . in the preferred embodiment of this invention the position of the device is changed simply by compressing the exposed end of the earplug .