Toothed belts made of a thermoplastic polyurethane compound can be provided with welded cleats for use primarily in transport applications.
The selection of the cleats design depends on the transported object and purpose of the transport. The cleats can be made in almost any shape and design.
Attributes
It is recommended that the profile spacing “A” correspond with the pitch of the belt. This allows the best spacing tolerances, and minimizes the effects of the belt’s overall length tolerance on the profile spacing. Profiles can be spaced on non-Pitch increments. However, if non-Pitch spacing is used, the cumulative tolerance of the belt length must be considered. Cleats may be located above the tooth (1) or outside the tooth (2), with maximum belt flexibility being achieved when the cleat is positioned over the tooth.
The strength, and therefore the capacity of the
profile depends primarily on the size of the welded foot. The strength of the cleat is affected by the type and direction of the force applied to it. Under high loads, the failure mode will normally be either bending or distortion of the cleat and belt, or in some cases, the polyurethane may actually tear.
The most important considerations while dimensioning a cleat are the size of the base of the profile (“foot” of the profile) and the position of the cleat on the belt. The cleat thickness can affect the flexibility of the belt, and can determine the minimum allowable pulley diameter. The flexibility of the belt can be maximized, however, by positioning the profile directly over the tooth of the belt. As the thickness of the foot of the cleat increases, the minimum pulley diameter in the system must
be increased according to the table.
For profiles requiring a wide base, such as
pushers, one foot should be left unwelded. This
allows for flexing around the pulley yet it remains
rigid when loaded.
If large profiles are required as cleats, then it
is necessary, that they are either segmented or
slotted.
Profiles with holes for securing paddles or other attachments can be produced. Holes are either drilled before bonding, or are molded into the profile depending upon the volume and requirements of the application. Tolerances of the hole placement depends upon whether the holes are drilled or molded. The tolerance of the hole from the belt surface is subject to the welding process of the foot and the belt surface. Generally, tolerances are as shown on the right-hand side.
Profiles can be molded with metallic inserts. These are particularly useful in some applications to replace roller chains with attachments. The actual inserts can either be manufactured or provided by the customer.
The welding process can cause a weld bead of polyurethane between belt back and the lower profile edge. This can be removed on customer request.
All profiles are perpendicular to ±1°.
