bicounet on "Disable Admin Bar"

Hello,
I have WP 3.7.1 and I would like to remove the WordPress admin bar that appears at the top .
Someone can delete?
I placed in the theme functions.php file:

remove_admin_bar function () {
show_admin_bar (false);
}
add_action ('after_setup_theme', 'remove_admin_bar');

But it does not work !

Then how to log out of wordpress without admin bar?
Thank you for your help