Summary:
There are two main styles of climbing with ropes: traditional, and sport. Traditional climbing involves carrying your own pieces of protection up with you and placing them into natural cracks and crevices of the rock you are climbing which is then connected to you through your rope. Sport climbing is much simpler in that you carry up draws with carabiners attached and clip them to bolts already drilled into the side of a rock face. Both styles offer access to different types of vertical features and it is important to understand that principles behind each of their mechanisms designed to safely protect you from falling to the ground.
Bolts:
For sport climbing, climbers ascend a pre-established route developed with the intent to follow a line of bolts to clip to in order to protect yourself from falling to far. By climbing whats called a sport draw to the bolt and then climbing your rope to that draw, you are able to remain secured to that section of the wall. A danger to sport climbing is that the bolts can be somewhat spread out on a climb requiring the climber to climb well above the last bolt which may in some cases result in a bigger and sometimes dangerous fall. In general, bolts are placed in locations where it there is a natural rest on the route or before a more difficult section so in the case you do fall it is in a generally more safe place to do so.
There are several types of bolts used with different practicality associated with the type of rock you are bolting (sandstone, granite, limestone, etc...). In essence they all have similar functional characteristics and so we will just look at the most popular type of climbing bolt- the wedge bolt. This bolt requires a pre-drilled hole to be inserted to which it is able to enter with a light tap from a hammer. Once inserted to the threads at the head, the bolt is then set in place via torquing from a wrench. This applied force results in the wedge at the end of bolt to be driven up against a sleeve causing it to expand to the exact diameter of the hole it was drilled. This prevents the bolt from being pulled out of the rock when climbers take a fall onto the hangar attached to the bolt.
Falling onto a bolt is now seen as a very safe and secure option when lead climbing. Bolts that are placed correctly are rated to upwards of 26 kilo-newtons and can last for several decades in some rock types. Though often a safety precaution overlooked is the state of the bolt and the surrounding rock. Only in relatively recent years has a major push began within the industry to using stainless steal bolts and hangars which are much more resistant to corrosion and weathering.
Active and Passive protection:
In traditional(trad) climbing, climbers make use of two types of protection: active and passive. The more simple of the two in mechanistic terms is passive which relates to gear such as hexes and nuts. These are placed into cracks with downward constrictions with the intent that if you were to fall onto them the force would be absorbed in the direction of your fall and that the constriction will prevent the nut from coming out of the rock as the only thing keeping it there is the force of gravity.
The engineering of nuts and hexes is such that the small aluminum body is able to absorb the force of a falling person by distributing it over the rock that is in contact with on both sides. A disadvantage to nuts is that the constrictions to place them in may sometimes be rather shallow which may cause a climbers movement above the nut to pull out the piece from the pull of the rope upwards thus leaving a possibly dangerous fall in it's absence. Another downside to this type of protection is that if a large enough fall force is applied to a placed nut it can potentially become fixed into the crevice and unable to be easily, if at all, removed.
The engineering of nuts and hexes is such that the small aluminum body is able to absorb the force of a falling person by distributing it over the rock that is in contact with on both sides. A disadvantage to nuts is that the constrictions to place them in may sometimes be rather shallow which may cause a climbers movement above the nut to pull out the piece from the pull of the rope upwards thus leaving a possibly dangerous fall in it's absence. Another downside to this type of protection is that if a large enough fall force is applied to a placed nut it can potentially become fixed into the crevice and unable to be easily, if at all, removed.
With active protection, the pieces are designed with adjustable camming lobes with the function of being able to fit a more variable range of cracks and similar natural features.
The springs that adjust the size of the lobes are such that it creates enough friction to ensure the device does not fall out of or down the crack which is a big advantage over passive protection as a natural constriction is not required.
The mechanics of these devices are such that when a climber takes a fall onto it, that downward force is converted into outward pressure of the rocks and thus is able to take a much large force than that of falling climber if placed correctly. An issue encountered with these devices is that it is necessary to place these pieces of gear into a mostly parallel crack in order for the lobes to be equally distribute the fall force and these cracks may be harder to find in some types of rock formations.
The springs that adjust the size of the lobes are such that it creates enough friction to ensure the device does not fall out of or down the crack which is a big advantage over passive protection as a natural constriction is not required.
The mechanics of these devices are such that when a climber takes a fall onto it, that downward force is converted into outward pressure of the rocks and thus is able to take a much large force than that of falling climber if placed correctly. An issue encountered with these devices is that it is necessary to place these pieces of gear into a mostly parallel crack in order for the lobes to be equally distribute the fall force and these cracks may be harder to find in some types of rock formations.
