Buckingham
Ox Block

Buckingham produces this rigging pulley with integrated swivel and carabiner to meet the needs of arborists and utility line workers. At the most basic level, the Ox Block is just a swiveled swing-side pulley with integrated carabiner becket:

The swivel helps the pulley orient to the load for maximum efficiency and minimal rope wear - this example is missing the roll pin which secures the swivel bolt. The separate swinging cheek plate opens by pressing the recessed button and permits mid-line attachment. The release button is only recessed and does not have the double catch found on the Rock Exotica Omni-Block pulleys and the Petzl Spin pulleys. Notably, the pulley sheave is recessed within the side plates, minimizing potential rope wear or something lodging between the sheave and the sideplate.

As with other becketed pulleys, the carabiner becket can be used to build a mechanical advantage system by attaching a rope termination or additional blocks/pulleys - but because Buckingham has integrated a carabiner into the pulley sideplate as a single rigid piece, the spine can also be used as a friction bar to belay/control a load. Wrapping the rope around the spine adds friction, and the square profile provides more friction than a round profile bar.

As opposed to a closed becket or friction ring, open shape of the carabiner allows a user to easily vary the friction for different loads, as well as tie-off/snub the load with a half-hitch, in the same manner as a horn, cleat or bollard. The gate adds overall strength and some security.

Arborists and lineworkers commonly use oversized blocks designed for rigging down loads, and heavy loads are usually lowered by a worker operating a ground-based descent control device. The Ox Block is for medium duty loads with a higher MBS than typical PPE pulleys, but not strong enough to handle heavy dynamic loads. The major advantage is that the friction device is integrated into the block, making for an integrated workflow and permitting a single climber to control the load while aloft rather than coordinating with a ground worker each time a load is lowered.

In addition to lowering wood and equipment, Buckingham markets the Ox Block as suitable for lowering live loads during aerial rescues.

Buckingham has a number of overview and training videos about the Ox Block on their YouTube channel.

This example has a more elongated swivel eye than those pictured on the Buckingham website in 2023.

Note: I have photographed this device with the carabiner upright to match how other carabiners in the collection are displayed.