For lifts to be used to accommodate loads that are rolled on to the lift platform the preferred configuration includes the use of a pit installed lift. This places the top surface of the lift platform flush with the adjacent approach surface (a floor or driveway), this results in a flat approach onto the lift platform.
In some applications it is not possible or feasible to install the lift into a pit. In these applications a surface installed dock lift or lift table can be utilized. A surface installed dock lift or lift table requires a means to get the pallet truck, cart etc. from the grade/floor level up and onto or off the lift platform. This is referred to as an approach ramp.
Depending upon the model of equipment the approach ramps can be hinged end or sometimes the side of the platform, when fully lowered it makes contact with the grade/floor level. The hinged approach ramp raises and lowers with the platform.
A fixed approach ramp is bolted to the grade/floor level and is typically 1” away from the lift platform edge. The fixed approach ramp remains in position as the lift platform raises and lowers. The lift platform is equipped with either beveled toe guards or electric toe sensors to prevent a potential shear factor as the platform edge lowers to the approach ramp position.
To maintain a safe percentage of approach ramp incline/decline the ratio of 1:6 is used. For example a Pentalift 4.3” low /closed height lift table has a 24” long approach ramp, a Pentalift 6” low/closed height dock lift has a 36” long approach ramp etc. This ratio may be changed to reduce the incline grade by increasing the length of the ramp to require less effort to move the load up the ramp.
A bridge plate is hinged to a side or end of the lift platform. Its purpose is to act as a transition plate from the lift platform to a truck bed or as a transition plate from the lift platform to a second elevation. Bridge plates are generally not a long as ramps as they do not have to accommodate an inclined transition. The lift platform can be positioned to accommodate a flat transition over the bridge plate. Bridge plates are most commonly manufactured from checker plate steel however aluminum bridge plates are available as an optional extra.
As standard hinged bridge plates are available with lengths ranging from 18” – 42” long, widths ranging from 48” – 96” wide. With the dock lift or lift table sitting on grade or at floor level the hinged bridge plate downward motion is restricted and does not contact the grade or floor level.
Bridge plates are available as a one piece hinged assembly or as a 2 piece split hinged assembly. Manual bridge plates are equipped with lifting chains to accommodate their raising and lowering. They are stored in the slightly over-center back from the vertical position and manually lowered when required to contact the truck bed or the second elevation for load transition.
The hinged bridge plate thickness depends upon a combination of the lifting capacity (the heavier the lifting capacity the thicker the transition bridge plate) or upon the length/span of the bridge plate. Depending upon the weight of the hinged bridge plate(s) they can be equipped with optional lift assist springs for ease of operation.
On many models of Pentalift lifting equipment the one piece hinged bridge plate(s) is also available with fully hydraulic operation removing all manual requirements to raise or lower the hinged bridge plate assembly.
This link is to a Pentalift LPE Dock Lift brochure. The back page of the brochure shows both an approach ramp and a hinged bridge plate in use. https://www.pentalift.com/wp-content/uploads/2021/04/LPE-Brochure.pdf
For additional information on any Pentalift products please contact the Pentalift Sales Department.