Cable Grip
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A cable grip is a device for propelling a
vehicle A vehicle (from la, vehiculum) is a machine that transports people or cargo. Vehicles include wagons, bicycles, motor vehicles (motorcycles, cars, trucks, buses, mobility scooters for disabled people), railed vehicles (trains, trams), wa ...
by attaching to a
wire rope Steel wire rope (right hand lang lay) Wire rope is several strands of metal wire twisted into a helix forming a composite ''rope'', in a pattern known as ''laid rope''. Larger diameter wire rope consists of multiple strands of such laid rope in a ...
(called a haul rope) running at a (relatively) constant speed. The vehicle may be suspended from the cable, as in the case of
aerial lift An aerial lift, also known as a cable car or ropeway, is a means of cable transport in which ''cabins'', ''cars'', ''gondolas'', or open chairs are hauled above the ground by means of one or more cables. Aerial lift systems are frequently employ ...
s such as a
gondola lift A gondola lift is a means of cable transport and type of aerial lift which is supported and propelled by cables from above. It consists of a loop of steel wire rope that is strung between two stations, sometimes over intermediate supp ...
(''télécabine''), may be guided by
rail Rail or rails may refer to: Rail transport *Rail transport and related matters *Rail (rail transport) or railway lines, the running surface of a railway Arts and media Film * ''Rails'' (film), a 1929 Italian film by Mario Camerini * ''Rail'' ( ...
s, as in a cable traction railway, or may be self-guiding, as in a
button lift A surface lift is a type of cable transport for snow sports in which skiers and snowboarders remain on the ground as they are pulled uphill. While they were once prevalent, they have been overtaken in popularity by higher-capacity and higher-co ...
. Typically, multiple vehicles will use the same cable; where just one or two vehicles are in use they will tend to be attached to the cable permanently such as in
funicular A funicular (, , ) is a type of cable railway system that connects points along a railway track laid on a steep slope. The system is characterized by two counterbalanced carriages (also called cars or trains) permanently attached to opposite en ...
s. While the cable grips used in the original cable railways were manually operated, requiring considerable skill and strength, modern cable grips tend to be automatic. Given that the cable runs at a relatively constant speed, accelerating the vehicle to match the speed of the cable presents a technical difficulty; possible methods are to apply the grip gradually, to accelerate the vehicle (e.g. by guiding wheels) prior to applying the grip, or to use a sprung linkage between the grip and the vehicle. The cable must also be able to handle friction from the grip and increased load while the vehicle is accelerating. Cable grips have additional uses, such as supporting electric or structural cables for pulling or laying of the electric or structural cable itself. In such use they may also be called cable pulling grips, cable socks, or cable stockings.


The Eppelsheimer Bottom Grip

This is the type of grip used in the cable cars of
San Francisco San Francisco (; Spanish language, Spanish for "Francis of Assisi, Saint Francis"), officially the City and County of San Francisco, is the commercial, financial, and cultural center of Northern California. The city proper is the List of Ca ...
. The grip is attached to the lead truck of the car (or both trucks, in the case of double-ended cars), and is a
field-replaceable unit A field-replaceable unit (FRU) is a printed circuit board, part, or assembly that can be quickly and easily removed from a computer or other piece of electronic equipment, and replaced by the user or a technician without having to send the entire p ...
. While side grips and even top grips have been used, the sheer number of rope (cable) changes, crossings, and "let-go" curves make the bottom grip, i.e., one in which the jaws open directly downward, the most practical type. The operating lever raises and lowers the center plate of the grip, which in turn operates the jaws. With the lever fully forward, the grip is open, and the cable is free to fall out, which is necessary when the cable crosses under another line, reaches the end of a line, or negotiates a "let-go" curve. With the cable lifted into the jaws, the operating lever is pulled back, forcing the jaws between two fixed rollers, and capturing the cable between the grip's replaceable mild-steel dies, but without applying pressure. To start moving the car, the operating lever is pulled back further, squeezing the cable between the dies. The grip was designed by the German railway mechanical engineer
William Eppelsheimer William Eppelsheimer (January 26, 1842– June 9, 1920) was a tramway engineer known for his work on cable car systems. He was born in Alzey in Germany and studied engineering at the Polytechnikum Karlsruhe. in 1868 he left Germany by ship f ...
in around 1880. See also
Andrew Smith Hallidie Andrew Smith Hallidie (March 16, 1836 – April 24, 1900) was the promoter of the Clay Street Hill Railroad in San Francisco, USA. This was the world's first practical cable car system, and Hallidie is often therefore regarded as the inventor of ...
.


Vehicles using cable grips


Suspended

*
Gondola lift A gondola lift is a means of cable transport and type of aerial lift which is supported and propelled by cables from above. It consists of a loop of steel wire rope that is strung between two stations, sometimes over intermediate supp ...
(''télécabine'') *
Detachable chairlift A detachable chairlift or high-speed chairlift is a type of passenger aerial lift, which, like a fixed-grip chairlift, consists of numerous chairs attached to a constantly moving wire rope (called a ''haul rope'') that is strung between two (or ...


On rails

* Cable traction railway *
People mover A people mover or automated people mover (APM) is a type of small scale automated guideway transit system. The term is generally used only to describe systems serving relatively small areas such as airports, downtown districts or theme parks. ...


Self-guiding

*
Button lift A surface lift is a type of cable transport for snow sports in which skiers and snowboarders remain on the ground as they are pulled uphill. While they were once prevalent, they have been overtaken in popularity by higher-capacity and higher-co ...


References

* George Hilton: The Cable Car in America, Stanford University Press 1997, ;Notes {{DEFAULTSORT:Cable Grip Aerial lifts Cable railways Vertical transport devices