Provided is an electric winch apparatus capable of preventing irregular winding of a wire rope caused by landing of a hoisted-down suspended load. The electric winch apparatus includes a winch drum (5) around which a wire rope (2) is wound, an electric motor (8) which rotates the winch drum (5), an operation lever (13a), a measurement unit (18) which measures a tension index value corresponding to a tension in the wire rope (2), and a controller (12) which controls motion of the electric motor (8). The controller (12) stops motion of the electric motor (8) when an operation in a lowering operation direction is applied the operation lever (13a) and a tension average value as an average value of a tension in the wire rope (2) becomes less than or equal to a predetermined tension reference value, the average value of the tension corresponding to an average value of the tension index value in a predetermined period.

A load-relieving apparatus includes a wire cable 36 with a free end and a fixed end opposite to the free end, a locking part 361 being attached to the free end, a winding part 334 configured to wind the wire cable 36 from a fixed-end side thereof, a pulley 335 interposed between the winding part 334 and the locking part 361, and configured to stretch the wire cable therebetween, and a cover 336 with a through hole 338H formed therein through which the wire cable 36 is inserted, the cover 336 being interposed between the locking part 361 and the pulley 335, and formed so as to cover at least a part of the pulley 335. Further, the through hole 338H is configured so that a relative position of the through hole 338H with respect to a rotation axis of the pulley 335 changes.

A pipe bursting system and method, and components thereof, are described wherein a bursting head assembly pulled by a cable employs a relatively small pneumatic impactor (hammer) and a relatively large cable tension to impose a cyclical stress on the pipe being burst to cause fatigue failure of the pipe, resulting in lower size and power requirements, and higher efficiency for a given set of job requirements.

A pipe bursting system and method, and components thereof, are described wherein a bursting head assembly pulled by a cable employs a relatively small pneumatic impactor (hammer) and a relatively large cable tension to impose a cyclical stress on the pipe being burst to cause fatigue failure of the pipe, resulting in lower size and power requirements, and higher efficiency for a given set of job requirements.

The three operations of hoisting, hoisting, and stopping are automatically performed by using the pulley and the position sensor, so that the general-purpose winch can be easily provided with the auto-tension function. The present invention provides the winch that is inexpensive and has the short delivery time. The three operations of hoisting, hoisting, and stopping are automatically performed by using the pulley and the position sensor, so that the general-purpose winch can be easily provided with the auto-tension function. In two pulleys where wire rope is suspended, the distance between the pulleys can be to changed according to the tension of the wire rope; if the tension increases, the distance between the pulleys decreases and the position sensor operates. As the result, the winch turns to a lowering motion, and the distance between the pulleys increases due to the action of the force of the rodless cylinder; if the tension decreases, the distance between the pulleys increases and another position sensor operates. Therefore, the winch turns into the winding operation and the distance between the pulleys is reduced; the wire rope returning operation and the wire rope pulling operation described above are repeatedly performed due to the operation of the two position sensors, so that the wire rope controls the tension of the constant tension.

The three operations of hoisting, hoisting, and stopping are automatically performed by using the pulley and the position sensor, so that the general-purpose winch can be easily provided with the auto-tension function. The present invention provides the winch that is inexpensive and has the short delivery time. The three operations of hoisting, hoisting, and stopping are automatically performed by using the pulley and the position sensor, so that the general-purpose winch can be easily provided with the auto-tension function. In two pulleys where wire rope is suspended, the distance between the pulleys can be to changed according to the tension of the wire rope; if the tension increases, the distance between the pulleys decreases and the position sensor operates. As the result, the winch turns to a lowering motion, and the distance between the pulleys increases due to the action of the force of the rodless cylinder; if the tension decreases, the distance between the pulleys increases and another position sensor operates. Therefore, the winch turns into the winding operation and the distance between the pulleys is reduced; the wire rope returning operation and the wire rope pulling operation described above are repeatedly performed due to the operation of the two position sensors, so that the wire rope controls the tension of the constant tension.

Cargo securement device (CSD) for securing cargo includes a top encasement and a bottom encasement; and, a center gear rotatably secured to at least one of the top encasement and the bottom encasement. The device further includes one or more spools, wherein each spool includes a spool gear for cooperatively engaging with the center gear. A retractable strap attaches to each spool.

A detachable line guide is provided. A screw with a helical groove is provided. A guide is positioned a fixed distance perpendicular to the screw and can travel laterally freely. The guide includes a follower which is attached to the guide by a spring. The follower is biased into the groove. Rotation of the screw causes the follower to track the groove and move the guide laterally. The guide is configured for a line to pass therethrough. When the line exerts a lateral force above a predetermined threshold against the guide, the follower rides up and out of the groove as the spring is compressed.

A detachable line guide is provided. A screw with a helical groove is provided. A guide is positioned a fixed distance perpendicular to the screw and can travel laterally freely. The guide includes a follower which is attached to the guide by a spring. The follower is biased into the groove. Rotation of the screw causes the follower to track the groove and move the guide laterally. The guide is configured for a line to pass therethrough. When the line exerts a lateral force above a predetermined threshold against the guide, the follower rides up and out of the groove as the spring is compressed.

A wire pulling windier apparatus attachable to a tractor, loader or other mobile transport device capable of receiving attachments has a pass through frame attachable to the mobile device, a vertical support member on the frame for supporting a first winch with cable for attaching and pulling a fence wire to be tensioned, a second winch for raising and lowering a slide block assembly through which the first winch cable is guided to allow pulling the first winch cable at different vertical heights, and has winch tension limiting apparatus.