Electrical connector

1. An electrical connector comprising;

a housing made of insulator and provided with an opening through which a circuit board is inserted into the housing,

a plurality of conductive contacts arranged in the housing, each of said conductive contacts having a fixed part engaging with a board-shaped portion of the housing and an operating part movable to the fixed part, and

an actuator provided to be rotatable to the housing for engaging with the conductive contacts and to take up a first station and a second station selectively for moving the operating part of each of the conductive contacts to come into press-contact with one of the connecting terminals corresponding thereto so that the circuit board is held by the conductive contacts when the circuit board is inserted into the housing through the opening provided thereon and the actuator is shifted from the first station to the second station and for moving the operating part of each of the conductive contacts to get out of press-contact with the corresponding one of the connecting terminals so that the circuit board is loosened from holding by the conductive contacts when the circuit board is inserted into the housing through the opening provided thereon and the actuator is shifted from the second station to the first station,

wherein said conductive contacts arranged in the housing include first and second contacts, each of said first and second contacts are configured to have one of substantially the same space between the fixed and operating parts thereof and substantially the same space between the operating part thereof and the board-shaped portion of the housing when the actuator is postured to take the first station and the circuit board is not inserted into the housing,

wherein the operating part of each of the first contacts is configured to exert a first temporary holding force on the circuit board inserted into the housing when the actuator is postured to take the first station and the circuit board is inserted into the housing through the opening provided thereon, and

wherein the operating part of each of the second contacts is configured to exert a second temporary holding force on the circuit board inserted into the housing when the actuator is postured to take the first station and the circuit board is inserted into the housing through the opening provided thereon, the second temporary holding force exerted on the circuit board being different from the first temporary holding force exerted on the circuit board.

2. An electrical connector according to claim 1 , wherein the actuator has a plurality of cams each engaging with one of the first and second contacts arranged in the housing and operative to move the operating part of one of the first and second contact to come into press-contact with the connecting terminal provided on the circuit board inserted into the housing through the opening provided thereon when the actuator is shifted from the first station to the second station, and each of the cams corresponding to the first contacts is configured to engage the operating part of one of the first contacts in a first predetermined position and each of the cams corresponding to the second contacts is configured to engage the operating part of one of the second contacts in a second predetermined position different from the first predetermined position when the actuator is postured to take the first station and the circuit board is inserted into the housing through the opening provided thereon.

3. An electrical connector according to claim 1 , wherein the first contacts and the second contacts are arranged alternately in the housing.

4. An electrical connector according to claim 1 , wherein the first contacts are disposed at intervals of a predetermined number of the second contacts.

5. An electrical connector according to claim 1 , wherein the actuator is positioned at a side of the housing opposite to another side of the housing on which the opening is provided.

6. An electrical connector according to claim 1 , wherein the first contacts are disposed at both end portions of an arrangement of the first and second contacts.

7. An electrical connector according to claim 6 , wherein at least one of the first contacts is disposed also at a central portion of the arrangement of the first and second contacts.

8. An electrical connector comprising;

a housing made of insulator and provided with an opening through which a circuit board is inserted into the housing,

a plurality of conductive contacts arranged in the housing, each of said conductive contacts having a fixed part engaging with a board-shaped portion of the housing and an operating part movable to the fixed part, and

an actuator provided to be rotatable to the housing for engaging with the conductive contacts and to take up a first station and a second station selectively for moving the operating part of each of the conductive contacts to come into press-contact with one of the connecting terminals corresponding thereto so that the circuit board is held by the conductive contacts when the circuit board is inserted into the housing through the opening provided thereon and the actuator is shifted from the first station to the second station and for moving the operating part of each of the conductive contacts to get out of press-contact with the corresponding one of the connecting terminals so that the circuit board is loosened from holding by the conductive contacts when the circuit board is inserted into the housing through the opening provided thereon and the actuator is shifted from the second station to the first station,

wherein said conductive contacts arranged in the housing include first and second contacts, each of said first and second contacts are configured to have one of substantially the same space between the fixed and operating parts thereof and substantially the same space between the operating part thereof and the board-shaped portion of the housing when the actuator is postured to take the first station and the circuit board is not inserted into the housing,

wherein the operating part of each of the first contacts is configured to exert a first temporary holding force on the circuit board inserted into the housing when the actuator is postured to take the first station and the circuit board is inserted into the housing through the opening provided thereon,

wherein the operating part of each of the second contacts is configured to exert a second temporary holding force on the circuit board inserted into the housing when the actuator is postured to take the first station and the circuit board is inserted into the housing through the opening provided thereon, the second temporary holding force exerted on the circuit board being different from the first temporary holding force exerted on the circuit board,

wherein the actuator has a plurality of cams each engaging with one of the first and second contacts arranged in the housing and operative to move the operating part of one of the first and second contact to come into press-contact with the connecting terminal provided on the circuit board inserted into the housing through the opening provided thereon when the actuator is shifted from the first station to the second station, and each of the cams corresponding to the first contacts is configured to engage the operating part of one of the first contacts in a first predetermined position and each of the cams corresponding to the second contacts is configured to engage the operating part of one of the second contacts in a second predetermined position different from the first predetermined position when the actuator is postured to take the first station and the circuit board is inserted into the housing through the opening provided thereon, and

wherein each of the cams corresponding to the first contacts and each of the cams corresponding to the second contacts are different in shape from each other, and each of the cams corresponding to the first contacts is operative to come into contact with the operating part of one of the first contacts and each of the cams corresponding to the second contacts is operative to be in noncontact with the operating part of any of the second contacts when the actuator is postured to take the first station and the circuit board is inserted into the housing through the opening provided thereon.

9. An electrical connector comprising;

a housing made of insulator and provided with an opening through which a circuit board is inserted into the housing,

a plurality of conductive contacts arranged in the housing, each of said conductive contacts having a fixed part engaging with a board-shaped portion of the housing and an operating part movable to the fixed part, and

an actuator provided to be rotatable to the housing for engaging with the conductive contacts and to take up a first station and a second station selectively for moving the operating part of each of the conductive contacts to come into press-contact with one of the connecting terminals corresponding thereto so that the circuit board is held by the conductive contacts when the circuit board is inserted into the housing through the opening provided thereon and the actuator is shifted from the first station to the second station and for moving the operating part of each of the conductive contacts to get out of press-contact with the corresponding one of the connecting terminals so that the circuit board is loosened from holding by the conductive contacts when the circuit board is inserted into the housing through the opening provided thereon and the actuator is shifted from the second station to the first station,

wherein said conductive contacts arranged in the housing include first and second contacts, each of said first and second contacts are configured to have one of substantially the same space between the fixed and operating parts thereof and substantially the same space between the operating part thereof and the board-shaped portion of the housing when the actuator is postured to take the first station and the circuit board is not inserted into the housing,

wherein the operating part of each of the first contacts is configured to exert a first temporary holding force on the circuit board inserted into the housing when the actuator is postured to take the first station and the circuit board is inserted into the housing through the opening provided thereon,

wherein the operating part of each of the second contacts is configured to exert a second temporary holding force on the circuit board inserted into the housing when the actuator is postured to take the first station and the circuit board is inserted into the housing through the opening provided thereon, the second temporary holding force exerted on the circuit board being different from the first temporary holding force exerted on the circuit board,

wherein the actuator has a plurality of cams each engaging with one of the first and second contacts arranged in the housing and operative to move the operating part of one of the first and second contact to come into press-contact with the connecting terminal provided on the circuit board inserted into the housing through the opening provided thereon when the actuator is shifted from the first station to the second station, and each of the cams corresponding to the first contacts is configured to engage the operating part of one of the first contacts in a first predetermined position and each of the cams corresponding to the second contacts is configured to engage the operating part of one of the second contacts in a second predetermined position different from the first predetermined position when the actuator is postured to take the first station and the circuit board is inserted into the housing through the opening provided thereon, and

wherein the operating part of each of the first and second contacts is provided with an engaging projection, said engaging projection provided on the operating part of each of the first contacts and said engaging projection provided on the operating part of each of the second contacts being different in shape from each other, and each of the cams corresponding to the first contacts is operative to come into contact with the engaging projection provided on the operating part of one of the first contacts and each of the cams corresponding to the second contacts is operative to be in noncontact with the engaging projection provided on the operating part of any of the second contacts when the actuator is postured to take the first station and the circuit board is inserted into the housing through the opening provided thereon.