Wrench with a fixed maximum operational torque

A wrench comprising:

• a casing including a compartment, the casing further including a retaining section defining a retaining space;
• a retainer received in the compartment of the casing and having a first end and a second end, the retainer being pivotally movable in the compartment about the first end of the retainer;
• a drive member securely engaged with the retainer to move therewith, the drive member having a driving portion on an end thereof that is located outside the casing for engaging with a fastener, the drive member being disengageable from the retainer by means of directly pulling the drive member away from the casing along a longitudinal axis of the drive member;
• and
• a retaining means for retaining the retainer in place, the retaining means having a first portion attached to the second portion of the retainer and a second portion retained in the retaining space;
• wherein when a rotational force applied to the casing is smaller than an engaging force between the retaining section of the casing and the second portion of the retaining means, the retainer and the drive member are turned to thereby turn the fastener, with the second portion of the retaining means being retained in the retaining space;
• and
• wherein when a rotational force applied to the casing is greater than the engaging force between the retaining section of the casing and the second portion of the retaining means, the casing slides while the retainer and the drive member are not turned, with the second portion of the retaining means disengaging from the retaining space.

A wrench comprising:

• a casing including a compartment, the casing further including a retaining section defining a retaining space;
• a retainer received in the compartment of the casing and having two ends, the retainer being pivotally movable in the compartment about a center of the retainer;
• a drive member securely engaged with the retainer to move therewith, the drive member having a driving portion on an end thereof that is located outside the casing for engaging with a fastener, the drive member being disengageable from the retainer by means of directly pulling the drive member away from the casing along a longitudinal axis of the drive member;
• and
• two retaining means for retaining the retainer in place, each said retaining means having a first portion attached to an associated one of the ends of the retainer and a second portion retained in the retaining space;
• wherein when a rotational force applied to the casing is smaller than an engaging force between the retaining section of the casing and the second portion of the retaining means, the retainer and the drive member are turned to thereby turn the fastener, with the second portion of the retaining means being retained in the retaining space;
• and
• wherein when a rotational force applied to the casing is greater than the engaging force between the retaining section of the casing and the second portion of the retaining means, the casing slides while the retainer and the drive member are not turned, with the second portion of the retaining means disengaging from the retaining space.