A safety apparatus for coupling with a ladder and methods for manufacturing and using same. The safety apparatus includes an engagement member defining an engagement member recess for receiving a selected structure and a retention member rotatable relative to the engagement member such that the retention member extends distally from the engagement member in an open position and extends proximally to the engagement member in a closed position. The retention member transitions from the open position to the closed position for enclosing the selected structure within the engagement member recess when weight is applied to the ladder and transitions from the closed position to the open position for releasing the selected structure when the weight is removed from the ladder. The ladder advantageously can inhibit unexpectedly detachment from the selected structure during use and does not require manual disengagement of the selected structure after use is complete.

A retractable ladder assembly comprising a lower frame fixed below an enclosure for a mechanical closure device and a moveable upper frame. The upper frame is disposed below the enclosure or removed entirely from the enclosure when not in use to prevent access from unauthorized personnel. The lower end of the upper frame engages the upper end of the lower frame and a link member on the upper frame engages an anchor within the enclosure to establish an extended ladder mode.

A retractable ladder assembly comprising a lower frame fixed below an enclosure for a mechanical closure device and a moveable upper frame. The upper frame is disposed below the enclosure or removed entirely from the enclosure when not in use to prevent access from unauthorized personnel. The lower end of the upper frame engages the upper end of the lower frame and a link member on the upper frame engages an anchor within the enclosure to establish an extended ladder mode.

A fall arrest system for a silo having a ladder is described. Silos typically have a slopping top and substantially vertical sides. Typically, multiple independent fail arrest systems are used, one for the sloping top and one for the vertical sides. The single fall arrest system described includes: a safety cable, having a top end and a bottom end, to which in use a user connects to; a collar for fitting at the top of the silo, around the neck of the silo to which the top end of safety cable is attached; a pulley at the transition of the slopping top and substantially vertical sides, wherein the pulley supports the safety cable at the transition; and securing means for securing the bottom of the safety cable at the base of the silo.

A cluster tool system, including: a load lock; a first wafer transfer module; a buffer module; a second wafer transfer module; wherein the load lock, the first wafer transfer module, the buffer module, and the second wafer transfer module are positioned in a linear arrangement; a first process module connected to the first wafer transfer module on a first side of the linear arrangement; a second process module connected to the second wafer transfer module on the first side; a third process module connected to the first wafer transfer module on a second side of the linear arrangement that is opposite the first side; a fourth process module connected to the second wafer transfer module on the second side; a first ladder assembly connected to the buffer module on the first side; a second ladder assembly connected to the buffer module on the second side.

A cluster tool system, including: a load lock; a first wafer transfer module; a buffer module; a second wafer transfer module; wherein the load lock, the first wafer transfer module, the buffer module, and the second wafer transfer module are positioned in a linear arrangement; a first process module connected to the first wafer transfer module on a first side of the linear arrangement; a second process module connected to the second wafer transfer module on the first side; a third process module connected to the first wafer transfer module on a second side of the linear arrangement that is opposite the first side; a fourth process module connected to the second wafer transfer module on the second side; a first ladder assembly connected to the buffer module on the first side; a second ladder assembly connected to the buffer module on the second side.

A safety device for a wall surface suction-type travel device that is configured to travel on a wall surface while being suctioned on the wall surface includes an extending member, a support base, and a safety rope. The extending member is configured to be disposed on the wall surface and bendable by self weight. The support base supports the extending member so as to allow the extending member to move in a direction along which the extending member extends. The safety rope connects the extending member with the wall surface suction-type travel device.

A safety device for a wall surface suction-type travel device that is configured to travel on a wall surface while being suctioned on the wall surface includes an extending member, a support base, and a safety rope. The extending member is configured to be disposed on the wall surface and bendable by self weight. The support base supports the extending member so as to allow the extending member to move in a direction along which the extending member extends. The safety rope connects the extending member with the wall surface suction-type travel device.

An apparatus and method for supporting a ladder on a roof having a ridge is disclosed herein. The apparatus includes a frame, a roof anchor, a first ladder engagement portion, a second ladder engagement portion and a wheel assembly. The first ladder engagement portion and the second ladder engagement portion attach the apparatus to the ladder. The wheel assembly enables the apparatus to be easily rolled up and down the roof and the roof anchor anchors the apparatus over the ridge of the roof to attach the apparatus, and thus the ladder, to the roof.

A bell hole box with an open bottom for protecting construction workers from wall cave-in when working below a surface of the Earth may utilize two, opposing, generally concave walls with generally straight panels portions. The two walls may be connected using multiple spreaders that are pinned or connected to each of the two, opposing walls. Each longitudinal end of the bell hole box is open to permit passage of a pipeline through it. Numerous vertical guard posts may be connected around a top frame rail and joined together with chains. The bell hole box may be lifted in and out of a hole with mounted lifting hooks.