Abstract: There is provided a cam type braking device for a ladder lifter arranged so that as soon as the lifting wire rope for the ladder lifter is broken, a brake cam is pressed against the associated ladder rail, whereby the lifter is braked and it is securely stopped at the position on the rail which it assumed at the time of breakage of the wire rope, without causing any large fall of the lifter.

Abstract: A working platform lifting apparatus for an aerial ladder truck, wherein the working platform movable up and down along the ladder is arranged so that it does not interfere with the extension and contraction of the ladder, that when it is stopped at any desired position it is automatically braked, that when it reaches its uppermost position it is automatically stopped and that in an emergency it can be lowered manually. Other merits and details of the construction will be made clear.

Abstract: A safety device is provided for association with an aerial ladder truck assembly to automatically detect a weight overload on the ladder unit of the assembly at any given angle. The safety means are characterized by providing ladder angle detecting means in the form of a disk provided with a plurality of contacts and a pointer operatively associated with the ladder which engages a given contact at a given angle position of the ladder, and a load indicating means which actuate a pointer mounted on a disk provided with a plurality of contacts, each of which indicates a load value with the angle indicating contacts and the load indicating contacts of each disk being electrically connected to one another and an alarm device to give an alarm when there is a weight overload on the ladder unit at the angle it is positioned.

Abstract: There is provided a ladder working limit based ladder stopping device for a vehicle equipped with a vertically and horizontally swingable and extensible ladder (or a fire engine truck), wherein a working limit of the ladder is preset on the basis of an extended length of the ladder corresponding to a particular vertical angle assumed by the ladder, so that when the combined situation of the vertical angle and extended length of the ladder reaches said preset condition, the operating mechanism for the ladder is automatically returned to its neutral position while actuating a warning device and turning on a marker lamp, the operating mechanism being then operated toward the safety side, whereupon the marker lamp is turned off to indicate that the ladder is now safe.

Abstract: A device for use with a high-altitude working vehicle provided with a vertically and horizontally revolvable and extensible ladder and an operator-carrying lifter movable up and down along the ladder, the device being characterized in that it allows the exension and contraction of the ladder only when the lifter is at a predetermined position, thereby securing safety of the operator riding in the lifter. Other advantages and details of the construction will be made clear.