A pivotable handle assembly for mounting on a support, the assembly comprising: a rotation-blocking portion comprising a pivot axis, the rotation-blocking portion for being rotatable about the pivot axis when in an unlocked position, and when in a locked position, the rotation-blocking portion for preventing its rotation about the pivot axis; a handle depending from the rotation-blocking portion; and a locking mechanism comprising a push-button and a lock release, the locking mechanism for locking the rotation-blocking portion in the locked position, and for unlocking the rotation-blocking portion in the unlocked position upon a pushing motion being applied to the push-button to actuate the lock release, the unlocked position thereby allowing the handle to be pivoted about the pivot axis, wherein the rotation-blocking portion comprises an inner bore, the locking mechanism comprising a plunger having a first end adjacent the push-button and being moveable inside the inner bore from the locked position to the unlocked position upon the pushing motion being communicated to the first end of the plunger via the push-button and wherein the lock release comprises a ball bearing; the inner bore comprises an opening; and the rotation-blocking portion defines an internal recess at least partially communicating with the opening, the ball bearing for moving out of the internal recess and lower into the inner bore upon the pushing motion being applied to the plunger, wherein the pivotable handle assembly is characterized in that: the plunger comprising an inwardly slanted end opposite the first end, the inwardly slanted end for allowing the ball bearing to move out of the internal recess upon the pushing motion being applied to the plunger. a rotation-blocking portion comprising a pivot axis, the rotation-blocking portion for being rotatable about the pivot axis when in an unlocked position, and when in a locked position, the rotation-blocking portion for preventing its rotation about the pivot axis; a handle depending from the rotation-blocking portion; and a locking mechanism comprising a push-button and a lock release, the locking mechanism for locking the rotation-blocking portion in the locked position, and for unlocking the rotation-blocking portion in the unlocked position upon a pushing motion being applied to the push-button to actuate the lock release, the unlocked position thereby allowing the handle to be pivoted about the pivot axis, wherein the rotation-blocking portion comprises an inner bore, the locking mechanism comprising a plunger having a first end adjacent the push-button and being moveable inside the inner bore from the locked position to the unlocked position upon the pushing motion being communicated to the first end of the plunger via the push-button and wherein the lock release comprises a ball bearing; the inner bore comprises an opening; and the rotation-blocking portion defines an internal recess at least partially communicating with the opening, the ball bearing for moving out of the internal recess and lower into the inner bore upon the pushing motion being applied to the plunger, wherein the pivotable handle assembly is characterized in that: the plunger comprising an inwardly slanted end opposite the first end, the inwardly slanted end for allowing the ball bearing to move out of the internal recess upon the pushing motion being applied to the plunger.