A gantry robot construction is provided. The construction includes a pair of elongated substantially spaced parallel rails (112, 114), a bridge (120) spanning and substantially perpendicular to the rails and movable relative to the rails, and a robot head (134) and support mounted on the bridge and movable relative to the bridge. The rails are positioned along the width or shorter side of the work area (90) with the bridge spanning the length or longer side of the work area. An improved rack (150, 152) and pinion (200) apparatus is also disclosed that is used in association with the gantry robot construction. There is a zero degree pressure angle between the rack and pinion. In the pinion the base circle is congruent with the pitch circle (205).

Gantry robot construction and drive mechanism.

A Cornu's spiral is applied to a tooth profile of a gear. In accordance with the application of the gear, the Cornu's spiral may be modified two-dimensionally by some constant proportion. Since Cornu's spirals have similarity are similar, when a pressure angle is determined, the tooth profile can be standardized by a module, so that it is highly versatile. By replacing the tip of a tooth and the bottom of a tooth by another curve, such as an arc, the range of application can be increased. Since working is always by flank contact between a protrusion and a recess, contact surface stress is low. In addition, the radius of curvature of a dedendum is large. Therefore, tooth bending stress is low, and fatigue strength is high. Even if the number of teeth is small, an undercut is not produced. Even if there is no backlash, a smooth working is achieved, so that the tooth profile is suitable for devices requiring precise alignment.

Cornu's spiral tooth gear

A power-assisted steering system includes a gear mechanism, coupled to a steering column, with a gear and a mating gear. The two transmission gears have teeth (4, 5) via which they engage with each other, movement and power being transmitted from one gear to the other gear via effective profiles of their tooth faces (11, 12). In order to provide a gear mechanism that has an enhanced load-bearing capacity and at the same time can be manufactured in a simple and economical way, the effective profiles of the tooth faces (11, 12) of the gear and the mating gear contact over the height (h4, h5) of the teeth (4, 5).

Power-assisted steering having a gear mechanism

The invention relates to an engine auxiliary drive for a motor vehicle with a toothed-gear drive, comprising a first (1) and a second gear wheel (2) with teeth flanks (11, 12), engaged with each other, whereby the teeth flanks (11, 12) on the gear wheels (1, 2) in the force transmission region (13) are embodied without involute and progress directly or almost directly from a concave region into a convex region and the first gear wheel (1) is made from plastic.

Engine auxiliary drive for a motor vehicle with a toothed-gear drive

A W-N gear which has a surface strength at least nearly maximized for a given addendum and minimum pressure angle is realized by selecting a mean radius for the convex and concave circular arcs of the tooth profile in an appropriate range. Also, a dual=line mesh W-N gear of the character described which has a requisite face width minimized is obtained by selecting a mean arc radius which lies in the range referred to above and enables the addendum and dedendum points of meshing contact to appear at equal angle intervals.

Kiyoshi Kotake

Papers

W-N gear having a maximum surface strength