New Danfoss VLT® Decentral Drive E cient, reliable and powerful
New Danfoss VLT® Decentral Drive E cient, reliable and powerful
New Danfoss VLT® Decentral Drive E cient, reliable and powerful
You also want an ePaper? Increase the reach of your titles
YUMPU automatically turns print PDFs into web optimized ePapers that Google loves.
Cantilever axis assists<br />
tobacco-cutting skates<br />
WINCHESTER-BASED<br />
Garbuio Dickinson makes<br />
tobacco-cutting machines<br />
with a near-vertical action that<br />
minimises compression of the<br />
tobacco.<br />
The machines are fed by<br />
vibrating tray feeds that<br />
need to be removed for<br />
cleaning. The 1,800kg<br />
feeds are usually moved<br />
manually on air skates.<br />
“One customer however, wanted to take things a stage further<br />
<strong>and</strong> asked if we could devise something which would actually pull<br />
the feeder accurately into the machine,” says Garbuio Dickinson’s<br />
senior design engineer, Peter Todd. With only a 5mm clearance<br />
between the feed tray <strong>and</strong> the cutting machine sidewalls, he<br />
needed to find a linear motion system that would avoid contact<br />
between the two, <strong>and</strong> tolerate contamination by tobacco dust.<br />
Garbuio Dickinson chose HepcoMotion’s DLS3C linear actuator,<br />
which uses an aluminium beam to provide rigid support for<br />
cantilevered loads with minimal inertia. The actuator’s drive is<br />
mounted on the carriage <strong>and</strong> not connected to the end-plate, so<br />
the motor, carriage <strong>and</strong> cables remain stationary while the beam<br />
moves. For added safety, an overload clutch on the motorised<br />
gearbox limits the push/pull forces.<br />
The tray actuator that Todd designed consists of two linear<br />
systems, linked by a common shaft to ensure it moves in <strong>and</strong> out in<br />
parallel. The moving tray is supported by a pivoting mount that<br />
allows the connecting end of the tray to rise <strong>and</strong> fall as the feeder<br />
is lifted by its air skates.<br />
“In the event, with the air skates activated, the system wasn’t that<br />
dependant on being powered,” says Todd, “but the design of the guidance<br />
system has proved a major factor in the success of our product.”<br />
Screwjack goes with the flow<br />
A screwjack system is helping<br />
to control the flow of one of<br />
Britain’s shortest rivers – the<br />
River Morar which links Loch<br />
Morar to the sea, a few<br />
hundred metres away, on<br />
Scotl<strong>and</strong>’s west coast. The jack<br />
raises or lowers a sluice gate<br />
at a weir near a hydroelectric<br />
dam <strong>and</strong> fish ladder at the<br />
west end of the Loch.<br />
The 100kN rotating screwjack<br />
in a ram-style linear actuator<br />
design, is used, with a motor<br />
<strong>and</strong> reduction gearbox, to<br />
raise or lower the gate to<br />
control local water flows.<br />
Garbuio Dickinson’s feed tray movement<br />
system relies on a pair of linear actuators<br />
(under the tray) linked by a shaft<br />
A screwjack controls the level<br />
of Scotl<strong>and</strong>’s River Morar<br />
The screwjack operates over a<br />
stroke of 2,350mm, pivoting on its integral trunnions located midway<br />
on the ram's outer tube. At the end of the ram, a clevis end with<br />
spherical bearing connects the jack to the weir gate.<br />
When the jack was first installed in 2001, it was driven by a 2.2kW<br />
geared motor with position feedback coming from end-of-stroke<br />
limit switches <strong>and</strong> an absolute encoder that links back to the control<br />
system. Since then, it has been upgraded by replacing the motor<br />
with an alternative with an integrated h<strong>and</strong>wheel. The screwjack was<br />
supplied by Power Jacks, the Scottish linear actuation specialist.<br />
No more<br />
corkscrews<br />
<strong>New</strong>: Chainflex ® CFBRAID.<br />
Braided control cable. Corkscrews are now finally a<br />
thing of the past, thanks to the way we braid our cables.<br />
Available as 4-core or 8-core. Shielded <strong>and</strong> unshielded.<br />
Also the very latest:<br />
Chainflex ® CFLG.T: Now 21% thinner<br />
Chainflex ® CFBUS: Now with UL/CSA<br />
Chainflex ® CF98: Now 4xd<br />
igus ® (UK) Limited 51A Caswell Road Brackmills Ind. Estate Northampton NN4 7PW<br />
Phone 01604-677240 Fax 01604-677242 sales_uk@igus.co.uk<br />
www.drives.co.uk November/December 2010 27