All of you have good things to say and understandably with emotion. Sorry a BendPak product had to be the cause of so much passion. We'll see if the admin guys let this post go through. I hope they do because it can be very educational.
Being the SR. VP. of BendPak and having worked here for over 25 years, I can honestly say that I do know what I'm talking about and feel motivated to defend our great products and name. I do apologize for the misguidance on behalf of our customer service person however. Communication or the lack thereof seems to be the culprit.
This is the story on arm restraints. You will notice that I did not refer to them as arm locks because they are not. No industry professional will refer to them as arm locks.
This is verbatim how the OSHA endorsed standard reads. ANSI/ALI ALCTV: 2006 Standard for Automotive Lifts – Safety Requirement for Construction, Testing and Validation
10.2.8 / Swing Arm Restraint Test
Method – If the lift design requires swing arm restraints for compliance with this standard, (all two-post models do) a typical swing arm restraint shall be tested on a lift, or an equivalent test fixture. The test shall employ the longest swing arm available for the lift, positioned within the normal range of arm deployment for lifting. The swing arm restraint shall be tested be applying a load equal to one hundred fifty ( 150) pounds in the plane perpendicular to the arm’s normal swing motion, at the end of a fully extended arm, and perpendicular to the arm’s axis of extension.
Why is the standard worded that way? Why not make the arm restraints “locks” and have them hold more load? Imagine they did…….you are working under a raised truck that unbeknownst to you had an arm dislodge and was now precariously being balanced on a rounded frame edge. The arm “locks” however are doing their part and holding that arm in position….but for how long - Tick-tock. Having arm restraints with more load holding capacities would invariably cause more damage than good. Safe operation and understanding of proper lifting procedures is the cure. Train and re-train.
Back in the early eighties many two-post lifts had no arm restraints whatsoever. You would raise a rigid chassis and although all four pads were under the vehicle, only three were actually making contact. Same thing happens today as well. Remember it only take three points of contact to make something balance. In those days however, a mechanic walking by one of the free-floating arms could easily dislodge the arm inadvertently or….. the slightest shift could cause the arm to “shoot out” fiercely with a bang as it slipped off the corner of an undercoated frame contact point.
Arm restraints are to prevent just that. Many people tend to believe that they are to stand firm as a 9,000 lb. truck is falling. In that event, there is no mechanical devise in the world that would prevent the eminent fall - best to stand clear. If you did a rough calculation of the moment loads placed on the arms under normal use you would understand. Now try adding about 20,000 pounds more due to the sudden shift in weight and shock load.
Arm restraints work in this manner. They are a spring loaded spur and rack gear design. You can disengage them simply by pulling up on the handle - swing your arms into position, then let go of the handle. The rack gear will come down onto the spur gear and be ready to engage during movement. In addition, when the lift rests on the ground, a release rod coming into contact with the base frame raises the rack for you making it easier to positin the arms on the ground. However, when the lift is raised, the restraints become activated. That is what our rep was referring to. The devises should always be inspected, set and adjusted to operate when the lift is elevated. If for some reason the components are damaged or inoperable, please consult the factory.
If your lift is equipped with arm restraints whether they are Rotary’s or BendPak, please inspect them and adjust them as necessary to prevent unloaded pads from shooting out from under the vehicle. Do not count on them to compensate for mis-loaded vehicles and poor training. And be very careful when stacking height adapters. No more than 9” max please.
Again, I do apologize for the misguidance on behalf of our customer service rep.
Hey Mysterync – send me an email. I’ll see what I can do. [email protected]
