Security cameras' plastic bearings halve parts

Edited by the Engineeringtalk editorial team Nov 10, 2004

Plastic bearing specialist Sarnatech BNL, has begun production of a complex custom-designed bearing assembly for access and video control specialist, Bewator.

Plastic bearing specialist Sarnatech BNL, has begun production of a complex custom-designed bearing assembly for access and video control specialist, Bewator.

With an overall height of 230mm and a diameter of 210mm, the injection moulded pan and tilt bearing assembly is hidden inside Bewator's Solaris surveillance dome.

Breaking away from the commonly available domes on the market, the Solaris dome is claimed to offer a level of accuracy, speed and configurability never experienced before.

Impressed with Sarnatech BNL's wealth of experience and understanding of the functions and requirements of security camera applications, Bewator commissioned the North Yorkshire plastic bearing firm to work with it in partnership on the internal mechanics of Solaris.

The result of the company's specialist design expertise and knowledge of plastics has seen the replacement of heavy, noisy and expensive steel pressings and gears with plastic pulleys and belts.

As well as the two double row precision bearings, the assembly has been designed to include many additional integrated features, cutting costs and shortening the supply chain by reducing components said Sarnatech.

Where ty-wraps would traditionally be used, Sarnatech BNL has integrated routing channels into the design to keep the electronic cables tidy and replaced metal screws with fully integrated moulded clips.

Those integrated moulded features have not only halved the component count but also significantly reduced maintenance time, meaning the unit can be stripped down in minutes.

Sarnatech BNL had to take the temperature of both the motor and outside temperatures, the rigidity of the assembly and the high speed of the system into consideration when choosing materials.

Under manual control, Solaris' pan and tilt speed is proportional to the degree of zoom allowing accurate target acquisition and tracking.

A 360 degrees per second top speed permits near instantaneous response to alarms, so a smooth precision movement with the minimum amount of judder was required.

Sarnatech BNL's reduction in the weight and size of the bearing assembly ensured the camera a quicker period to settle into its pre-set positions said the company.

Sarnatech took on the full project management of the sub-assembly, managing the purchasing of components such as tilt sensors, timing belts, PCBs and motors and assembling them at the same time as the bearings.

"Sarnatech BNL's bearing solution has far exceeded our initial expectations in both design and cost savings.

We went to them with our initial design concepts for Solaris and their specialist expertise has given us a truly integrated product from a single supplier.

I've enjoyed every minute of this project and am very much looking forward to working with Sarnatech BNL again in the future.

They know the limitations in tooling and materials and their unrivalled experience has helped Bewator greatly in the development of this project, bringing it in both on time and on budget," said Bewator's development manager, Ewan Burnett.

"We've really enjoyed working with Bewator on this project.

To enable us to work in close partnership with our customers, we use four different CAD systems at Sarnatech BNL.

Using Bewator's preferred system - Solid Works - for this project, meant that we were able to develop their initial design concepts, seam free.

The common software also speeded the project up considerably, taking only ten months from initial enquiry to full production," said Sarnatech BNL design manager, Adrian Naylor.