Underwater measurement and 3D modelling of the relevant lock gate components is no easy task and requires a great deal of knowledge and expertise. We call this 'knowledge is measurement'. Thorough knowledge of the different gate types is essential for smart lock gate measurement.
A lock with lift gates is easily recognised by its impressive tall lift towers. The lift gate is a vertically movable lock gate that rises with each lock movement. A vertical guide rail system is mounted on the lift towers on either side of the lock head. These, together with the guide roller mounted on the gate, ensure smooth up and down movement. The lift gate operating mechanism is located at the top of the traverse connecting the two lift towers. Watertightness is secured by the correct sealing of the lower end post positioned on top of the cill and the vertical end posts in the recesses on either side of the cill. In the case of double retaining gates, these recesses are on either side of the lock gate. It is, therefore, necessary to determine the exact position of the various components of the lock head and lock gates. For the lock head, these components are the cill, the vertical bearings, the guide rails, the operating mechanism and any guides for the counterweight. For the lock gates: the lower and vertical end posts, the guide rollers and the engagement points of the operating mechanism.
The key feature of a lock with rolling gates is the presence of gate recesses adjacent to the lock chamber. The gate moves into this side chamber in the open position. The operating mechanism is primarily located in the mechanism chamber at the far end of the gate chamber. The watertightness of rolling gates is comparable to that of lift gates but is only guaranteed at the bottom by a raised cill. The principle of double-retaining is also common to this type of lock gate. It is also necessary to accurately determine the position of the various components of the lock head and lock gates. For the lock head, these are the cill, the vertical bearings, the lower rails and any upper rails, the operating mechanism and the associated guide systems. For the lock gates: the lower and vertical end posts, the lower and upper rollers, if any, and the engagement points of the operating mechanism.
Locks with mitre gates can be identified by the open-swinging gates, which are positioned at an angle of one-third in the lock chamber when closed. The hinged side of the gate is integrated into the chamber wall allowing it to be concealed in the gate recess when open. The rotational axis of this type of gate consists of a lower bearing, called the pintle, and an upper bearing, called the gudgeon.
There are two types: mitre gates with a fixed pivot point and gates with a free pivot point. The watertightness of mitre gates is ensured by the so-called 'watertight frame', which consists of the cill, side and front bearings. In addition, force transmission is an essential element of mitre gates. For fixed pivot points, these are the pintle and gudgeon pin and for free pivot points, the rear bearings.
To obtain a correctly functioning lock head, it is even more critical to determine the position of the various components of the lock head and the lock gates. For the lock head, these components include the cill, the exact position of the cill edge, the rear and side bearings, the pintle and gudgeon and, to a lesser extent, the operating mechanism. For the lock gates, these components are the lower, side and rear end posts in relation to the axis of rotation formed by the centres of the pintle and gudgeon pin.