Welcome to Safe Lifting Partners
The top two modes of overhead crane and hoist failure, per research from noted former P&H engineer Charle Totten, are wire rope and rigging issues related to cowboy operators and bridge/long travel (along the runway) machinery resulting from out-of-tolerance rails and runways. I can help you find site services and components to make any aspect…
The 5:1 Safety Factor
Recently I read a note by a terrific wire rope expert on the west coast of Canada (Dean, thanks for your insight!) about improper use of rigging components and why the 5:1 safety factor exists. If you’re not familiar, certain parts overhead cranes and lifting gear must have a 5:1 safety factor. That means if…
Wire Rope Hoist Reeving
Hoists may be reeved in many ways to increase capacity at decreased speed , or to get greater speed with less capacity. With the same horsepower, it is impossible to increase speed without a corresponding decrease in capacity. The reeving may be varied almost indefinitely. The worlds “single” or “double” used with hoist reeving indicate…
How a mechanical load brake works
Many older electric wire rope hoists have a mechanical or Weston-type load brake that was introduced in the 1930’s. Often the working of this secondary brake is a mystery to most of us so here is a great explanation of how the device works. The Load Brake is called an automatic load break because it…
Overhead Crane Bridge Brakes
A recent project involving the upgrade of a 1970’s overhead crane highlighted the need to discuss various types of bridge brakes. There are at least three types of bridge brakes in mainstream use today: (1) the spring-applied flange-mounted brake most commonly used; (2) the foot-mounted “shoe brake” electrically operated; (3) the hydraulically-operated “shoe brake” that…
What is a limit switch?
Most overhead cranes are required to have limit switches governing their hoisting operation. This means a switch(es) capable of stopping the up or down motion when the hook has traveled past the design limits. If the hook travels past those design limits, very expensive damage may occur, or injury and death of the operator. This…
What are dynamic brakes?
An overhead or gantry crane and hoist can have two types of brakes: (a) a physical brake shaped like a disc or a drum (think about that brake which you see behind the wheels on your car) that is spring-set when the controls are release; (b) a dynamic brake, where the entirety of the machinery…
Crane Expertise | Crane Components
Our team has 20+ years of in-field, on-crane experience. We have outstanding professional qualifications.
Ask us about these pictures. They’re all real projects.
I’ve always been into machines…
As a kid I spent time at my dad and grandfather’s office watching trains roll by on the mainline across the street. Pretty soon I became interested in the building behind the office instead of the train tracks in front. We had forklifts, cherry-pickers, old Thunderbirds, and every week big trucks carried bright yellow cranes out the back door. That was the 1980s.
Today I’ve spent 20+ years in the crane business. Although I’m ultimately a creature of the office and have a couple degrees, I make it a priority to spend a lot of time in the field so I am up to date and understand the give-and-take of the work we do. Because of that, the equipment we supply doesn’t just meet code, it exceeds expectations and makes life easy. The expert witness work I do provides very practical insight as well as good analysis of the applicable codes.
Tad Dunville
20+ Year Crane Expert