The overcenter linkage is movable to an overcenter position for locking the rear bow in the extended position.

The overcenter linkage extends between the linkage mechanism and the rear bow.

A push-pull chain actuator (1) comprises a housing with a chain exit/entry opening (4) and a sprocket (2) arranged to engage a push-pull chain (3).

The top includes a roof cover, a linkage mechanism, a rear bow and an overcenter linkage.

Operating means (40) has an over-centre action to maintain the cable grip in the closed condition during use.

The overcentre mechanism comprises a trip lever and a stressed spring arranged mechanically in series between spaced-apart abutments.

An over-centre camlock mechanism (7) is retractably extendable from each major edge surface (2, 3).

The control arm is configured to control relative motion of the first and second arms into and out of an overcenter lock position.

One feature of the closure is that the annular section (23) operates in an overcentre action to move the body part (3) from a raised position to a lowered position.

The first frame portion (5) has a plurality of over- centre camlock mechanisms (21) and the second frame portion (6) has a corresponding number of pins.

A clutch in which a driving plate (10) clamped against a driven plate (11) by a pressure plate (22) under action of over-centre toggle linkage (23).

A steam control for switching off the heating element of a water boiling vessel comprises a snap-acting bimetal arranged to determine the condition of an overcentre mechanism via a push-rod.

Each hook assembly has a hook member (34) pivoted for movement between a closed setting (Figure 4) and an open setting (Figure 5) and is of a load over centre design.

A spring loaded over-center draw latch is provided having a latch bail that exerts an upward force on the mating parts when the latch is closed.

The tensioning of the plastic sheet results in the edge (3) being stretched on the wall (5) so as to conceal the horizontal opening (41) of the cavity (4).