Provided is an orthogonal-axis power transmission device. The orthogonal-axis power transmission device according to an embodiment of the present inventive concept includes: a main structure assembly forming an exterior structure and having a space portion formed therein, the space portion being sealed; an input shaft assembly connected to one side of the main structure assembly, and to which rotational power of a motor is input; an output shaft assembly connected to the other side of the main structure assembly intersecting the input shaft assembly, and from which the rotational power of the motor is output; and a link assembly for changing a power transmission direction arranged to operate in the space portion of the main structure assembly to prevent propagation of noise or vibration, connected to the input shaft assembly and the output shaft assembly within the main structure assembly by a link method, and changing the power transmission direction from the input shaft assembly to the output shaft assembly.

A reduction gearbox for solar photovoltaic tracking is provided. A sum of an included angle between an outer end surface of a first limiting protrusion and an outer end surface of a second limiting protrusion and a central angle of a limiting stopper is less than or equal to 170, that is, an angle at which a gear rotates from a hard limiting position of the first limiting protrusion and the limiting stopper to a hard limiting position of the second limiting protrusion and the limiting stopper is greater than or equal to 190. A difference between a central angle of a gear ring of the gear and a central angle of a worm is greater than or equal to 180. A photovoltaic panel may be rotated to be perpendicular to the ground, so that snow accumulated on a photovoltaic panel surface can be cleared to the utmost extent.

Head extension for surface treatment operations including housing with first operative end and second operative end, both ends being open. Head extension incorporates cam assembly and holder assembly within housing. Cam assembly comprises motor, shaft, and plurality of cams configured to facilitate linear reciprocating movement. Holder assembly includes plurality of support plates and support loops configured to hold hoses used in surface treatment operations. Hoses extend through housing and interact with cams to achieve linear reciprocating movement. Head extension is designed for mounting on portable lifting equipment, such as portable crane or aerial work platform, thus allowing human operator to perform surface treatments at elevated or hard-to-reach locations while remaining on ground. Head extension is adaptable for use with various types of surface treatment media, including abrasives, water jets, and chemical sprays, providing versatility and enhancing operational efficiency and safety.

A conveyor drive roller for a conveyor system. The conveyor drive roller has a hollow drum rotatably connected to a first stationary shaft and a second stationary shaft, and defines a sealed chamber. The chamber at least partially encloses means to rotate the hollow drum about the first and second stationary shafts. A pressure relief valve is positioned on the conveyor drive roller in fluid communication with the inside of the chamber. The pressure relief valve is configured to reduce a gas pressure increase inside of the chamber caused by a rise in a temperature of the conveyor drive roller during operation.