Introduction To Gramac Quartz Belt Curves

Belt Curves, Belt Turns or Powered Belt Curves are generally considered to be a specialist type of belt conveyor and as such they are supplied by a specialist manufacturer. Gramac Quartz is the division of Amber Industries Ltd which has specialised for over 30 years in the manufacture of Belt Curves for many different combinations of load duty, arc and width formats. These time served belt curves are marketed under the Gramac Quartz brand name.

Gramac Quartz Belt Curves - Key Product Features

Gramac Quartz Friction Driven Belt Curves provide a means of quietly and smoothly changing the direction of conveyed products at high speed whilst maintaining the products spacing, orientation and alignment.

Gramac Quartz Belt Curves
Gramac Quartz Belt Curves

Images of Gramac Quartz Belt Curves

Proven Track Record

Gramac Quartz Belt Curves have a proven track record of longevity and reliable operation around the globe in a variety of environments and industries including: post and parcel handling, airport baggage handling, warehouse and distribution centres, refrigerated storage units, print and packaging, laundries, cement, plaster and building materials, horticultural and garden fertilizer and compost products and many other general manufacturing and industrial applications where changes in direction of conveyed objects are required.

Robust Design

The Gramac Quartz Belt Curves robust and patented design consists of a strong and rigid frame fabricated from steel section and plate rolled and formed to give the desired angle and radius. A stiffened smooth steel slide bed is mounted within the frame to support the belt and over which the belt slides.

Tapered End Pulleys

Supported at each end of the curved frame by 'life greased' ball bearing units fixed to it are tapered conical pulleys manufactured in high density polypropylene on a steel shaft. These two pulleys can be adjusted in the horizontal plane by tensioning devices to provide the correct amount of tension in the belt which fits over them.

Maximum Power Transmission

At one end the drive pulley is coated / lagged with a non-slip, highly wear resilient and heat resistant material which positively grips the underside of the belt. The taper of the pulley allows it to engage the belt across its full width, even at high speed, and ensures maximum power transmission from a suitably sized geared motor unit fitted to the shaft of the drive pulley. This method of driving the belt is known as 'Friction Driven'.

Positive Belt Tracking

With any belt curves the tendency is for the belt to displace towards the centre as it travels. To Keep the belt running on the correct line Gramac Quartz Belt Curves use a method of positive tracking. The belts are supplied with roller bearings fitted to the reinforced outer edge of the belt which then run on guide rails built into the outer perimeter of the steel frame.

Fully Guarded

All Gramac Quartz Belt Curves are supplied with safety guards fitted to eliminate trap points and prevent inadvertent access to moving parts such as the roller guide bearings. These guards are designed to be lightweight for easy removal for maintenance purposes. Underside guarding is provided as standard.

Positive Belt Tracking

Friction Drive For Maximum Operating Life / Minimum Maintenance and Noise

Some manufacturer’s designs of belt curves use a roller bush type chain attached to the outside perimeter of the belt by means of punched holes through the belt and which is then driven by a sprocket either powered directly by a geared motor unit or linked to one by a toothed transmission belt or chain. This method of driving the belt is often referred to as a 'Positive Mechanical Drive'.

All Gramac Quartz Belt Curves use the ‘Friction Drive’ method which has three clear advantages:

In summary Gramac Quartz Friction Driven Belt Curves offer much greater reliability at the lowest cost of ownership over time.

Specifying GQ Belt Curves

There are three main dimensions which suffice to determine belt curves geometry. They are the subtended angle of the belt curves (A), the effective belt width (W) and the effective radius of the belt curves. The radius can be given as one of the following: Ro = the belt’s effective outer radius, Rcl = centre line radius and Ri = the belt’s effective inner radius. It is important to be clear about which one is being used.

The nomenclature adopted by Gramac Quartz when designating its ranges of belt curves models uses the outer radius dimension, for example:

Model Designation:

TR100 1600 800 90
Ro W A

In This Case:

The effective outer radius of the belt, Ro = 1600mm

The effective belt width, W = 800mm

The subtended angle of the belt curves, A = 90 degrees

TR100 at the beginning of the model designation indicates the model range and in this instance stands for Tapered Roller with a max diameter of 100mm.

Autocad footprint drawings of all our standard size belt curves can be supplied on request. Other special belt widths, radii and angles between 15° and 270° can be designed and manufactured to order to suit customers specific applications.

Standard Sizes/Tech Data...

Other key parameters and options that need to be specified are:

Travel Direction:

i.e. clockwise or anti-clockwise.

Travel Speed:

i.e. belt speed in M/sec measured at the centre line radius.

Motor Position:

The preferred position for the geared motor is horizontally mounted on the outer radius at the discharge end of the belt curves conveyor. On some larger radius formats it is possible to vertically mount the geared motor on the inner radius.

Motor Rating:

Gramac Quartz standard supply of geared motor unit is SEW SA47 helical worm geared to give specified c/l speed, 400Vac, 3ph, 50Hz, (IP54, IE2 compliant). Clients should clearly indicate if their requirements are different.

Belt Type:

There are many types of belt available from belt fabric manufacturers, including industrial grade, food safe (FDA approved) , wear resistant, chemical resistant, flame retardant and several different surface finishes including smooth top, lightly textured, high grip rough top, Available colours are usually black/dark grey, green, blue and white. Wherever possible we recommend the use of vulcanised splices to form endless belts and the avoidance of hooking systems on belt curves. Our engineers can help clients with the selection of belt type to suit the particular application.

Belt  Type
Belt  Type
Belt  Type


Gramac Quartz Belt Curves can be supplied with 'H' type floor supports made from RHS, outriggers for low level positions, side mounted brackets for suspending from above using threaded rods or our engineers can design special supports to suit the situation. Floor supports can be fitted with either anti-vibration footpads with +/- 50mm adjustment or with locking wheels/castors if required to be mobile.


Fabricated sheet steel sidewalls can be supplied to a max-height of 450mm (depending on belt curves footprint) above the top of belt.



Gramac Quartz house colour is RAL 5015 Blue, however our belt curves can be powder coated in any standard RAL colour at the client’s request.

Belt  Colour
Belt  Colour
Belt  Colour

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