In this third of a series of articles looking at the challenges surrounding machine building, Dan Rossek and Richard Wilkins of Omron examine how safety can be an enabler for increased productivity and reduced total cost of ownership. There are few issues in machine design that are more emotively loaded than safety, and it is
Loimex, Located in Barcelona, manufactures auxiliary machines to measure, wind, cut and store cable. It has been the leader in its sector for over 40 years. In an effort to maintain this position, the company works closely with Omron for the automation of their machines.
Cable winding machines make it possible for a single operator to wind cable from the original factory reels placed on reel holder racks or hydraulic jacks to empty reels, and to create coils using an additional winder. Conductors, cylindrical, braided, covered or bare cables of up to 100 mm in diameter may be simultaneously measured, rolled and cut to the specifications of each client.
Innovative automated system
Amongst Loimex’s products, the TR166-HE machine particularly stands out because of its innovative automated system that enables it to fill reels from 700 to 1600 mm in diameter, with a maximum reel width of 1150 mm and a maximum weight of 2000 kg. The machine has four main parts: a bench base, a weighbridge reel holder and a protective cage in the winding area, which are all built from steel pipe profiles, and a twine holder with cutting blade. The TR166-HE model is built from welded steel, creating a heavy-duty body. It has been designed to include a measuring device, a programmable counter, an additional winder, wheels and other accessories, all depending on the features the customer wishes the machine to have.
The wood reel is mounted inside the machine, between the two shafts and supported by cones. One of the shafts is manually activated and is blocked by a lever-activated ratchet system that is quick and easy to use. The other shaft is hydraulically activated by a keypad located on the machine’s safety device, perfectly positioned to permit moving the reel when the shaft is activated. This machine has been designed for the shortest possible machine preparation times and to keep the physical effort required by the operator to a minimum. The gear motor is installed directly on the drive shaft, achieving greater power and reducing the possibilities of malfunctions, since there is no need for a chain. Reels are raised and lowered by two hydraulic cylinders located on the machine arms, activated by a 1.5 C.V. hydraulic motor pump. This motor pump is used to activate the hydraulic shaft and may also be used to activate a hydraulic cutter and transport wheels, all controlled by push buttons on the control panel. (If the machine is equipped with them.) The drive arm, which bears part of the load and most of the traction stress from the reel, is equipped with ball bearings, giving it perfect transmission quality.
This machine is activated by an electric motor and a gearbox to perform the toughest work under optimum conditions. It is controlled by an Omron MX2 frequency inverter that makes it possible to select the ideal speed at all times during operation by means of a potentiometer. These speeds have been factory pre-set from 15 to 80 rpm, with progressive starts and stops. Upon special request, the machine may be programmed with other speed ranges.
The entire machine control is centralised in an Omron CP1L programmable logic controller, and the operator has access to all machine parameters through an NQ3 touchscreen. The machine automation with Omron control equipment has allowed Loimex to reduce machine assembly time, as many push buttons have been replaced by the touchscreen and the wiring has been simplified, as the inverters communicate with the programmable logic controller via MODBUS. In addition, the reel holder arms are equipped with special protection to prevent any possible accidents during the winding process as the result of carelessness on the part of the operator or any other employee. This protective device is articulated in two columns and equipped with two cylinders that assist when it needs to be opened, later maintaining it in an open position. An electrical installation with a stop microswitch is included to prevent the machine from starting up while the protective device is open, in compliance with European machine safety regulations, according to the CE mark. A twine holder with a cutting blade is incorporated into the machine to facilitate cable tying on the coils and reels.