Abstract: A multi-stage hinge assembly has a first connecting board, a second connecting board, a first hinge, a second hinge, an inner mounting lever and an outer mounting lever. The first connecting board has a first ring, a second ring and a recess. The second connecting board has a first ring and a second ring. The first hinge is mounted on the connecting boards. The second hinge is mounted on the connecting boards. The inner mounting lever is mounted pivotally on the second mounting bracket of the first hinge and the rotating head of the second hinge and has two retaining plates, a holding frame and a spring. The outer mounting lever is mounted pivotally on the second mounting bracket of the first hinge and the rotating head of the second hinge.

Abstract: A hinge with multiple resilient spacers has a body, a rotating element, multiple bolt assemblies and multiple resilient spacers. Both of the body and the rotating element have corresponding through holes. The bolt assemblies are mounted through the through holes of the body and the rotating element. The resilient spacers are mounted on the bolt between the body and the rotating element. Each resilient spacer has at least one surface selectively abutting the body and the rotating element. Each surface of the resilient spacer has multiple concentric grooves formed in the surface. With such an arrangement, the surfaces of the resilient spacers partially abut the body or the rotating element. Therefore the rubbing area of the resilient spacers are reduced. Such that greasing may be unnecessary and abrasion or noise may effectively prevented.

Abstract: A hinge assembly has multiple components that have mounting holes and mounting protrusions respectively. The mounting protrusions are formed on the components and correspond to and are mounted rotatably in the mounting holes respectively. Such that the hinge assembly is assembled without any additional connecting elements like bolts and fabrication of the hinge assembly may be convenient and low-cost.

Abstract: A trivalent chromium electroplating solution in accordance with the present invention contains at least one trivalent chromium salt for electroplating a chromium coating layer on a workpiece. By using the low toxic trivalent chromium to substitute highly toxic hexavalent chromium, an electroplating process of the present trivalent chromium electroplating solution has less pollution.

Abstract: A duel-axle hinge has two adjusting assemblies, a connecting assembly, two lifting assemblies and a positioning gear assembly. The adjusting assemblies are attached to a screen of a liquid crystal display (LCD). The lifting assemblies are attached to a support of the LCD. The screen is turned via the adjusting assemblies to adjust the visual angle of the screen. The screen is turned via the lifting assemblies to adjust the height of the screen. The positioning gear assembly can provide positioning function to hold the screen at a desired height.

Abstract: A multi-stage hinge assembly has a first connecting board, a second connecting board, a first hinge, a second hinge, an inner mounting lever and an outer mounting lever. The first connecting board has a first ring, a second ring and a recess. The second connecting board has a first ring and a second ring. The first hinge is mounted on the connecting boards. The second hinge is mounted on the connecting boards. The inner mounting lever is mounted pivotally on the second mounting bracket of the first hinge and the rotating head of the second hinge and has two retaining plates, a holding frame and a spring. The outer mounting lever is mounted pivotally on the second mounting bracket of the first hinge and the rotating head of the second hinge.

Abstract: A method for chemical etching is disclosed for taking away oxidized film and removing cut as well as punched edge burs of harden-treated carbon steel (SK3, SK4 and SK5). Thereby, the fillet edge of the cut section is achieved. An oxidized film with a thickness of several micrometers is formed when a cut and punched steel is quenched and tempered at high temperature. Due to high strength and hardness of the steel, the oxidized film and edge burs are difficult to be removed by mechanical grinding. Therefore, a suitable electrolyte composes of only a little chemical reagent and oxidizer in deionized water is used to remove the oxidized film and punched bur simultaneously using chemical etching method.

Abstract: A method for chemical etching is disclosed for taking away oxidized film and removing cut as well as punched edge burs of harden-treated carbon steel (SK3, SK4 and SK5). Thereby, the fillet edge of the cut section is achieved. An oxidized film with a thickness of several micrometers is formed when a cut and punched steel is quenched and tempered at high temperature. Due to high strength and hardness of the steel, the oxidized film and edge burs are difficult to be removed by mechanical grinding. Therefore, a suitable electrolyte composes of only a little chemical reagent and oxidizer in deionized water is used to remove the oxidized film and punched bur simultaneously using chemical etching method.