Those adjustment means comprise a swivel ball-socket arrangement (18, 20).

The handles may pivot about an axis of a hinge joint or a point of a ball and socket joint.

A locking device (10) for a trailer and hitch of the ball and socket type, comprising an upper jaw (12) and a lower jaw (11) interconnected together by a shaft (14) for reciprocal movement relative to each other.

In view of facilitating the introduction of the anchor member the transverse pin (3) is connected with the shaft portion (2) by means of a resilient hinge joint (5).

Each keyboard unit (42) is attached to the armrests (36) via a ball-in-socket arrangement and includes half of a QWERTY keyboard (42) on one side, and a ten key numerical pad (44 or 46) on the opposite side.

The fore-end of the supporting arm is provided with a screw-head and the back-end of the supporting arm is jointed to the carrier with a hinge joint.

A portable umbrella support is disclosed which comprises a hollow telescopically formed shaft with a locking arrangement (9, 10) such as a ball and ratchet intelocking the telescopic sections at any selected length.

Each toggle joint-linkage (22) is a one-piece member with two rigid arms (115) connected by an undulating spring portion (112).

In an advantageous embodiment of the above, the free ends of the branches (21, 22, 23, 24) on the connecting lamellae (2) are taken up on the branches (13, 14) and (11a, 12a) of the support lamellae (1, 1a) by means of a joint or grooved connection.