Pentalift News Blog
Safety considerations when installing a lift table with a rotating top in a pit.
March 27, 2020, 8:41 am - The main concern is operator safety as it relates to eliminating potential pinch/shear/crush points when the lift table platform and rotating top lowers into the pit. First the lift table is equipped with electric toe sensors. Electric toes sensors are an interlocked 4 sided bar assembly that is suspended under the lower 4 sided edge of the lift table platform. When lowering if any obstruction (operator’s foot, debris etc.) contacts the suspended 4 sided perimeter bar the lowering stops immediately. Second the rotating top must in the home position or in line with the main platform to avoid any chance of lowering the underside of a partially off centered rotating top onto the top of an operator’s foot. In other words the rotating top is electrically interlocked so it must be “square” with the lift table platform before the lift table will lower. These 2 safety features are included in the standard operational design of any Pentalift pit installed lift and rotate lift table.
What is dock leveler deck cant?
March 20, 2020, 4:46 pm - In its simplest form a dock leveler is an adjustable ramp that provides lift truck access from the warehouse floor to the truck bed. Dock leveler deck cant allows the dock leveler deck and lip assembly to flex up to 4” laterally or from side-to- side. Typically incoming truck beds are pretty much level from side-to-side with the warehouse floor. However if there is an uneven build-up of snow, ice or debris outside the building the incoming truck bed can be parked on an angle with one corner of the truck bed higher than the other when backed into the loading dock. When the dock leveler is operated the deck and extended lip assembly are lowered onto the truck bed. One side of the lowering lip assembly contacts the highest point of the truck bed; the deck cant feature allows the lip and deck assembly to flex laterally permitting the lip assembly to now lie flat on the uneven truck bed. With the dock leveler deck and lip assembly canted to match the uneven truck bed the lift truck can now easily and smoothly transition in and out of the trailer.
What is a Sure Stop Valve on a lift table?
March 13, 2020, 11:03 am - On an electro-hydraulic lift table the lift motor is mechanically coupled to the hydraulic pump. When the lift motor is activated the hydraulic system pumps the hydraulic oil to the lift cylinders and the lift table rises. When the lift motor is shut off by there is a slight overrun “freewheel” effect, the pump continues to pump oil for a split second and the lift table rises slightly. If precise positioning is required a Sure Stop Valve is added to the hydraulic circuit. At rest the Sure Stop Valve is normally closed. Activating the Up button turns on the lift motor and opens the Sure Stop Valve simultaneously allowing the hydraulic oil to flow through the valve to the lift cylinders. When the lift motor is shut off the Sure Stop Valve immediately closes. This immediate closure prevents the slight hydraulic overrun freewheel effect and the lift table stops at once. This Sure Stop Valve is often used in an upward indexing operation where precise, repetitive stopping is required.
What are the options for Dock Lift guard rails?
March 6, 2020, 2:55 pm - As standard dock lifts are supplied with removable guard rails. At the time of manufacture the guard rails are bolted to a threaded plate that is welded to the dock lift platform. These guard rails are now removable however they require hand tools to first remove the locking bolts, 4 locking bolts per guard rail. Based on the amount of work required and the time involved removing this style of guard rail is not a common practice to do repetitively. Another option is permanent guard rails, as the name implies these guard rails are permanently welded into position and require cutting equipment to remove. This is the least flexible design of guard rails available however some manufacturers provide this design as a cost cutting measure. In some applications there can be a requirement to regularly remove the guard rails an example would be a dock lift that is installed in front of a conventional dock leveler. This design of easily removed guard rails is referred to as pocket style guard rails; basically lift them up and out, no tools required. The dock lift services the low trucks by lifting the product up to the dock height, if a conventional trailer arrives at the loading dock the pocket style guard rails are temporarily removed. The trailer now backs over the closed dock lift to the dock leveler and is unloaded. When the truck departs the pocket style guard rails are quickly and easily re-installed on the dock lift.
What are lift table electric toe sensors and how do they work?
February 28, 2020, 2:55 pm - Electric toe sensors are most commonly used on lift tables that are installed in a preformed recessed pit. In a recessed pit installation there is the potential for introducing a shear hazard as the platform lowers into the pit. Electric toe sensors are an interlocked 4 sided bar assembly that is suspended under the lower edge of the lift table platform. The suspended perimeter bar assembly interacts with 4 limit switches, one per corner. When the down button is activated the electrical signal to lower the platform travels from the controller through the 4 limit switches to the power unit lowering valve. During the lift table descent if any obstruction such as an operator’s foot, debris etc. contacts the suspended perimeter bar a minimum of 1 of the limit switches will immediately open circuit. This open circuit breaks the electric signal that travels from the controller to the power unit lowering valve; this broken signal stops the lift table descent immediately. When the operators foot is retracted or the debris removed the lift table now returns to normal operation.
