The wafer assemblies include a base wafer and a re-settable wafer that may be adjustably coupled to the base wafer.

A key (13) is fitted into the coupling keyway (14) and the rotatable shaft keyway (15).

A cooperating sleeve (11 ) within the heel is provided with a keyway profiled to fit over a key (14) on the end of a pin (12) when the keyway and key are aligned.

A key (10) insertable into both the first and second keyways.

The dental instrument comprises a wedge and a matrix.

The second sliding wedge transmission (100) comprises a driving wedge (101) that can be moved between a support element (85) and the following wedge(71) in the wedging direction (4).

In the method, a plug unit having at least one keyway and at least one key (or tab) is mated to a receptacle unit having at least one key (or tab).

For this purpose, a key (28) on the sleeve engages a keyway (20) in the cylinder.

Each key slot (11) is matched with a torque-transmitting key (2).The upper end of the torque-transmitting key (2) is provided with a first connecting part, and the lower end thereof is provided with a second connecting part.

Furthermore, a spline hole (121) can be provided at an end of the wind wheel shaft (103) with a spline (122) inside the spline hole (121) in a clearance fit.

A wedge (18) for an anchor system (10) is disclosed.

Each ear has a retainer receiving opening.

Furthermore, the press board laminate (15a) has a key groove (34) having a complementary shape with respect to a key (26) of the shaft (5), said key being provided for the purpose of determining the circumferential position.

The brake shoe and brake plates are connected by a key or tang in one to a key way or slot in the other.

A key is disposed on the inner surface of the barrel (106), wherein a recess (154) is created within the key.