Audio jack having means for reliably securing terminals thereof

An audio jack includes a casing member defining an interior space having an opening. A cover is fixed to the casing member to seal the opening. Two sets of conductive terminal members are fixed in the interior space. Each set has a stationary member and a movable member that engages with the stationary member and is selectively disengageable therefrom. A plug receptacle is formed on the casing member for reception of a plug. A passage is defined inside the casing member for guiding the insertion of the plug. The insertion of the plug into the interior space establishes physical/electrical engagement with the movable members and forces the movable members to disengage from the stationary members. The cover has a barb engaging an opening defined in the casing and two resilient legs having barbed ends engaging shoulders formed on the casing thereby securely fixing the cover to the casing member. A positioning pin is provided on the cover to be forcibly fit into a hole defined in the casing member.

BACKGROUND OF THE INVENTION
 1. Field of the Invention
 The present invention generally relates to an electrical connector, and in
 particular to an audio jack type connector for transmitting audio signals.
 2. The Prior Art
 As the computer and information industries develop, the transmission
 frequency of audio signals increases in computer and information
 processing systems. Electrical connectors are developed to facilitate
 transmission of such high frequency audio signals. Examples of such
 connectors are disclosed in U.S. Pat. No. 5,075,518 and Japanese patent
 publication No. 5-90863. The device of U.S. Pat. No. 5,075,518 includes
 three conductive terminal members for electrically engaging a mating
 connector and comprises a complicated structure. The Japanese patent
 discloses an audio jack having five conductive terminal members that are
 not securely arranged therein.
 It is thus desirable to have an audio jack with a simple structure capable
 for effectively securing conductive terminal members therein.
 SUMMARY OF THE INVENTION
 Accordingly, an object of the present invention is to provide an audio jack
 having a simple structure.
 Another object of the present invention is to provide an audio jack having
 conductive terminal members securely fixed therein.
 To achieve the above objects, an audio jack in accordance with the present
 invention comprises a casing member defining an interior space having an
 opening. A cover is fixed to the casing member to seal the opening. Two
 sets of conductive terminal members are fixed in the interior space. Each
 set has a stationary member and a movable member that engages with the
 stationary member and is selectively disengageable therefrom. A plug
 receptacle is formed on the casing member for reception of a plug. A
 passage is defined inside the casing member for guiding the insertion of
 the plug. The insertion of the plug into the interior space establishes
 physical/electrical engagement with the movable members and forces the
 movable members to disengage from the stationary members. The cover has a
 barb engaging an opening defined in the casing and two resilient legs
 having barbed ends engaging shoulders formed on the casing thereby
 securely fixing the cover to the casing member. A positioning pin is
 provided on the cover to be forcibly fit into a hole defined in the casing
 member.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
 Referring to the drawings and in particular to FIGS. 1 and 2, wherein an
 audio jack constructed in accordance with the present invention is shown,
 the audio jack of the present invention comprises a first casing member 1
 and a second casing member 3, both made of nonconductive material. The
 first casing member 1 has a bottom face 120 having four edges from which a
 front wall 110, a rear wall 130 and two lateral walls 150 extend. An
 interior space 146 is defined between the walls 110, 120, 130, 150. The
 first casing member 1 also has a top face 140 forming an opening of the
 interior space 146.
 The front wall 110 has a plug receptacle 111 formed thereon for reception
 of a plug (not shown) for the transmission of audio signals. The plug
 receptacle 111 is in communication with the interior space 146. The bottom
 wall 120 of the first casing member 1 has a projection 125 formed thereon.
 The projection 125 is receivable in a hole formed on a substrate (not
 shown) for positioning purposes.
 Also referring to FIGS. 3 and 4, the first casing member 1 has a first
 terminal holding slot 141, a second terminal holding slot 142, a third
 terminal holding slot 143 and a fourth terminal holding slot 144 defined
 in the interior space 146 for respectively receiving and retaining a first
 conductive terminal member 210, a second conductive terminal member 220, a
 third conductive terminal member 230 and a fourth conductive terminal
 member 240 therein.
 The first terminal member 210 is U-shaped and has a first limb and a second
 limb from which an internal contact section 212 and an external contact
 section 211 extend, respectively. The external contact section 211 extends
 out of the interior space 146 through a first channel 1411 defined in the
 first casing member 1 and projects beyond the first casing member 1 via an
 opening 121 of the first channel 1411 defined in the bottom face 120.
 The second terminal member 220 is U-shaped and has a first limb forming an
 internal contact section 222 and a second limb having an external contact
 section 221 extending therefrom. The internal contact section 222 is
 received in the second terminal holding slot 142. The second limb of the
 second terminal member 220 is received in a second channel 1422 defined in
 the first casing member 1 and the external contact section 221 projects
 beyond the first casing member 1 via an opening 122 of the second channel
 1422 defined in the bottom wall 120.
 The first limb of the first terminal member 210 is resilient and biases the
 internal contact section 212 to engage with the internal contact section
 222 of the second terminal member 220. Preferably, the internal contact
 section 222 comprises a plurality of projections 223 for facilitating
 electrical engagement between the internal contact sections 212, 222 of
 the first and section terminal members 210, 220. In this respect, the
 first terminal member 210 may be regarded as a movable member, while the
 second terminal member 220 is a stationary member. The movable member 210
 is selectively separated from and electrically disengaged from the
 stationary member 220.
 The third terminal member 230 is U-shaped and has a first limb from which
 an internal contact section 232 extends and a second limb from which an
 external contact section 231 extends. The external contact section 231
 extends out of the interior space 146 though a third channel 1433 defined
 in the first casing member 1 and projects beyond the first casing member 1
 via an opening 123 of the third channel 1433 defined in the bottom wall
 120.
 The fourth terminal member 240 is U-shaped and has a first limb forming an
 internal contact section 242 and a second limb having an external contact
 section 241 extending therefrom. The internal contact section 242 is
 received in the fourth terminal holding slot 144. The second limb of the
 fourth terminal member 240 is received in a fourth channel 1444 defined in
 the first casing member 1 and the external contact section 241 projects
 beyond the first casing member 1 via an opening 124 of the fourth channel
 1444 defined in the bottom wall 120.
 The first limb of the third terminal member 230 is resilient and biases the
 internal contact section 232 to engage with the internal contact section
 242 of the fourth terminal member 240. Preferably, the internal contact
 section 242 comprises a plurality of projections 243 for facilitating
 electrical engagement between the internal contact sections 232, 242 of
 the third and fourth terminal members 230, 240. Similarly, the third
 terminal member 230 may be regarded as a movable member, while the fourth
 terminal member 240 is a stationary member. The movable member 230 is
 selectively separated from and electrically disengaged from the stationary
 member 240.
 In the embodiment illustrated, the first casing member 1 comprises two
 solid portions 16, 17 formed in the interior space 146 and spaced from
 each other to define a central passage 18 therebetween. The first and
 second terminal holding slots 141, 142 are defined in the solid portion 16
 and the third and fourth terminal holding slots 143, 144 are defined in
 the solid portion 17. The central passage 18 is substantially aligned and
 in communication with the plug receptacle 111 for accommodating the
 insertion of the plug. The internal contact sections 212, 232 of the first
 and third terminal members 210, 230 partially project into the central
 passage 18. Thus, the insertion of the plug actuates engagement between
 the plug and the first and third terminal members 210, 230 and deflects
 the first limbs of the first and third terminal members 210, 230 whereby
 the internal contact sections 212, 232 of the first and third terminal
 members 210, 230 are separated from the internal contact sections 222, 242
 of the second and fourth terminal members 220, 240. Preferably, the solid
 portions 16, 17 have an arcuate surface 160, 170 bounding the central
 passage 18 for facilitating insertion of the plug that is usually
 cylindrical.
 A grounding terminal member 250 is U-shaped and fits over an internal wall
 145 formed inside the interior space 146. The grounding terminal 250 has
 an internal contact section 252 extending from a first limb thereof. The
 internal contact section 252 extends into the central passage 18 for
 contacting the plug. The grounding terminal member 250 also has a second
 limb from which an external contact section 251 extends. The external
 contact section 251 projects out of the first casing member 1.
 In the embodiment illustrated, one of the lateral faces 150 of the first
 casing member 1 is provided with a slot 151 at a location corresponding to
 the internal wall 145 for receiving the second limb of the grounding
 terminal member 250. The slot 151 is preferably T-shaped or
 dovetail-shaped for securely retaining the second limb of the grounding
 terminal member 250 therein. A recess 152 is defined in the lateral face
 150 in communication with the slot 151 to form a shoulder 153 engageable
 by an inward barb 253 formed on the second limb of the grounding terminal
 member 250 for fixing the grounding terminal member 250 on the internal
 wall 145 of the first casing member 1.
 Also referring to FIG. 5, the external contact sections 211, 221, 231, 241,
 251 of the first, second, third, fourth and grounding terminal members
 210, 220, 230, 240, 250 that project out of the first casing member 1 are
 bent and shaped to lie substantially in a common plane thereby allowing
 the audio jack of the present invention to be surface mounted to a printed
 circuit board.
 The second casing member 3 which serves as a cover for the top opening side
 of the first casing member 1 is received in the opening of the interior
 space 146 to substantially seal the interior space 146 and form a
 continuous surface with the top wall 140 of the first casing member 1.
 Therefore, a periphery 315 of the second casing member 3 is fittingly
 engaged in the opening between the front, rear and lateral walls 110, 130,
 150 of the first casing member 1.
 The second casing member 3 has a bottom side 310 positionable on the solid
 portions 16, 17 to securely retain the terminal members 210, 220, 230, 240
 in position in the terminal holding slots 141, 142, 143, 144. The second
 casing member 3 also has a top side 320 opposite the bottom side 310. A
 positioning pin 311 is formed on the bottom side 310. The pin 311 is
 forcibly fit into a corresponding hole 147 defined in the first casing
 member 1 for attaching the second casing member 3 to the first casing
 member 1.
 The second casing member 3 comprises a barb 312 and the front wall 110 of
 the first casing member 1 is provided with an opening 112 for receiving
 and engaging with the barb 312. The engagement between the periphery 315
 of the second casing member 3 and the walls 110, 130, 150 of the first
 casing member 1, together with the barb 312 engaging the opening 112 of
 the first casing member 1, effectively prevents relative displacement of
 the second casing member 3 with respect to the first casing member 1 in a
 direction substantially parallel to the second casing member 3.
 The second casing member 3 also comprises two resilient legs 313 extending
 from the bottom side 310 thereof. The legs 313 are provided with a barb
 314 that engages a corresponding shoulder 134 formed on the rear face 130
 of the first casing member 1. Thus, relative displacement of the second
 casing member 3 with respect to the first casing member I is prevented in
 a direction substantially normal to the second casing member 3.
 Preferably, the rear face 130 is provided with two vertical slots 133 in
 which the shoulders 134 are formed. The slots 133 receive the legs 313
 therein and the barbs 314 engage the shoulders 134. Thus, the second
 casing member 3 is securely fixed to the first casing member 1. The first
 casing member 1 and the second casing member 3 together substantially
 enclose the terminal members 210, 220, 230, 240.
 Preferably, the second casing member 3 is provided with two spaced,
 elongate ribs 316, 317 on the bottom side 310 thereof. The ribs 316, 317
 further define the central passage 18 to facilitate insertion of the plug.
 Preferably, the ribs 316, 317 have arcuate faces corresponding to the
 arcuate surfaces 160, 170 of the solid portions 16, 17 of the first casing
 member 1.
 Preferably, the second casing member 3 is provided with openings 321 (FIGS.
 2 and 6) corresponding to each resilient leg 313. The openings 321 allow a
 user to insert an elongate object (not shown) therein for disengaging the
 barbs 314 from the shoulders 134 of the first casing member 1.
 In the embodiment illustrated, during insertion, the plug first contacts
 the grounding terminal member 250 and then contacts the internal contact
 sections 212, 232 of the first and third terminal members 210, 230. Thus,
 the internal contact sections 212, 232 of the first and third terminal
 members 210, 230 are separated from the internal contact sections 222, 242
 of the second and fourth terminal members 220, 240 thereby disconnecting
 the first and third terminal members 210, 230 from the second and fourth
 terminal members 220, 240.
 Although the present invention has been described with reference to a
 preferred embodiment thereof, it is apparent to those skilled in the art
 that there are a variety of modifications and changes that may be made
 without departing from the scope of the present invention which is
 intended to be defined by the appended claims.