From the late 1880s through the 1950s, inventors created a wide range of detachable grips. The mechanisms showed great imagination, and many were quite reliable. But beginning in the late 1950s, detachable grips began to coalesce around a more standard approach.

In the late ’50s Poma came into the aerial detachable business with the Type S grip (Fig. 1). Of course, Poma had been a long-time supplier for the detachable surface lift named after the company. Poma sold the Type S clear up into the 80s; thousands are still in operation.

Like many of its predecessors, the S grip was a spring grip; the diagram (Fig. 2) shows how it works. The toggle arm counters the spring tension. It’s on a spring rod (Fig. 2, no. 14), and it’s a little different from other grips in that it doesn’t connect directly to the grip jaw—there’s a wheel on the jaw and it’s used against a wedge on the spring rod; there’s a fixed rod (Fig. 2, unnumbered arrow underneath the wheel) on the terminal running rails which lifts the grip jaw up, and gravity drops the jaw when the grip closes with the spring rod applying the force to the jaw. The grip is locked open or closed depending on the placement of the carrier in the terminal.

Although many detachable lifts switched from bi-cable to monocable design with the introduction of detachable passenger lifts in the 1930s and ’40s, bi-cables made a return in the U.S. in passenger lifts in the late ’60s and early ’70s at resorts such as Vail (Fig. 3), Steamboat (Fig. 4) and Mammoth, among others. Most of these installations have been removed and replaced with machines of monocable design.

One example of the return to the monocable was the von Roll grip (also sold as Doppelmayr) used on the original detachable chair at Breckenridge, the first detachable quad in the world, in 1981 (Fig. 5). Garaventa made a similar unit. This grip, known as type AK3 (Fig. 6), was sold on numerous machines.


The March of Progress

Another aspect of modernization was the development of mechanical terminal conveyors. Originally, terminal conveyance was a manual operation. Typically, the first mechanical systems were chain drives and used tire acceleration as well. Mechanical systems such as these allowed more control of spacing and synchronization with the haul rope. The chain operated in the turn around, at constant speed, and the tires were used to vary the speed from loading to rope speed.

The Doppelmayr-style DS grip (Fig. 7, shown as a double grip) had a unique internal grip force detector—probably the first internal grip force detector ever made. Doppelmayr was innovative in this regard. In Fig. 7 you can see this linkage, and its roller, which if it were not attached correctly, would change position, and it would be detected by a destructive switch. The DS grip in one variation or another was the mainstay of Doppelmayr for 15 years. These grips are robust and will be in use well into the future.

We’re also getting into machinery that’s much more sophisticated electronically, so that we can tell that the grip has grip force, that it has all the critical components in it prior to launching, and that it has appropriately closed on the rope. Back in the good old days, there were no electronics, and detachable systems relied on having just basic sound mechanisms to get everything done. As the industry moved into the modern era, systems began to constantly monitor the position of the carriers for correct spacing. And this allowed for ever-higher capacities and rope speeds.

Von Roll was another grip innovator, particularly when it came to dual movable grip jaws. Fig. 8 is an example, although I can’t find anyone who thinks this particular grip was ever made or put into production. It used a lot of different mechanisms: a spring force in opening, and a wedge to create a symmetrically opening grip. Unlike most grips, in which only one grip jaw moves, both jaws moved in this grip. In theory, this makes it easy to close the jaws on the rope. With more conventional grips, when you put the grip on the rope, you bring the grip down over the rope and then the movable jaw pulls the rope over against the fixed jaw. The von Roll just brought the grip down on the rope and closed the jaw on it. A superb idea, but very complicated.

The VH grip, used on the Keystone gondola (Fig. 9), is a production version of the von Roll symmetrically closing grip (Figs. 10-12). It also uses gravity instead of springs to close the jaws. It was made in single and double grip versions; the Keystone gondola used the double.


Going Modern

The Mueller grip (Fig. 13) really begins to look a lot like the grips we’re installing today. It used a big coil spring. Agamatic and Leitner (Figs. 14-15) were also approaching the same basic modern grip design at the time.

Another interesting point: there has been an evolution in the way the carriers move through the terminal. On the Mueller, for example, you can see the grip had grooved wheels that ran on a rod. In other grips like the Leitner, we find the wheel to be more conventional, and it runs in a trough rail. At the time, in the 1980s, there was an equal split between these two types; now most everything runs in a trough rail.

Poma’s TB grip (Fig. 16)was supplied well into the late ’90s. It’s a very simple spring grip, you just press down on the spring, it opens it up (Fig. 17). This grip was a big player in the Poma line, a grip with an amazing performance history. There are hundreds of installations throughout the world with the TB grip.

But even as the trend was toward the more familiar spring grips we see today, some innovators were pursuing other concepts in detachable grips. The Girak (Figs. 18-19) was a very basic, simple grip, with a toggle arm and cam that operated the grip jaws.

Yan Kunczynski was an innovative designer and produced a completely different type of grip (Fig. 20). This Yan grip used a new idea, a wedging effect on the rope for grip force. The grip had rubber “marshmallows” which generated some energy for the grip; this is a yolk-type grip which squeezes the two rollers together. It works a lot like a clothespin. The yolk arms are attached directly to the grip jaw.

However, the Yan grip proved to be not very successful. The performance history on this grip was poor. There are no longer any in the States or North America.

And that brings us nearly up to the present. As the lift industry has consolidated in the past decade, we have now arrived at a more or less standard design for detachable grips. Modern electronics and terminal conveyance have advanced the operation of detachables a great deal over the last 30 years. But the basics of a detachable grip haven’t changed that much.

Today, as our passengers have come to appreciate the speed and capacities of a detachable, these lifts have come to be the signature lifts at many areas. But that will not always be the case. As we look into the future, combinations of technologies will propel the industry to ever-higher capacities. The funitel, using multiple haul ropes, allows ever-longer spans and higher cabin capacities. The most recent detachable grip innovation we’ve seen is the two track rope recirculation gondola system, or 3 S, combining the large vehicle and rope configuration of the reversible tramway with the recirculating detachable grip, where even higher capacities and high weather/wind resistance are possible. Before long, our current high-tech wonders will seem as primitive as those first ore cars the miners rode more than a century ago.


Note: much of the information and the photographs for this series were gleaned from the ropeway library at the Colorado School of Mines in Golden, Colo.