A rolling pebble may generate a landslide while an abandoned lit cigarette may generate a forest fire.

This frame is supported onto the bar (6) with articulation, while the frame (3) is supported onto the bar (7) with wheel rolling on frame (3).

Each tread belt is supported by a front roller and a rear roller, which is common to both treadles.

Here, the pump assembly (6) comprises a roller (31) which runs on a running surface (34) of the cam (10) and a roller shoe (30) which receives the roller (31).

The invention is of interest to producers of vehicles independently guided by means of a guide roller running on a rail.

Furthermore, the pump assembly (8) has a roller (30) which runs on a running surface (31) of the cam (7) and a roller shoe (17) which holds the roller (30).

The roller (26) may be configured to provide rolling contact between the outer surface (30) of the roller (28) and a cam lobe (20).

The pump assembly (6) further comprises a pump piston (11), a roller (21) running on a cam surface (22) of the cam (5), and a roller stem (20) receiving the roller (21).

A roller insert assembly (20) is installed within a cooling bed (22) having longitudinal members (24) and transverse members (26).

A roller (3) which rolls over the race faces (1a,2a) of the race rings (1,2) is formed of a ceramic such as silicon nitride.

The roller includes a shaft about which the roller rotates.

The roller body may include a first roller tread (154) disposed between a first end of the roller body and a second end of the roller body.

Alternatively, the contact roll is in the form of a composite cylindrical roll which has a shape of a combined larger-diameter roll and a small-diameter roll.

The roller is rotatably attached to the roller support frame for rotation about a roller axis.

The upper, inner cam follower has an upper locking means for coupling the upper, inner cam follower and the outer cam follower.