A shift mechanism for a bicycle and the like wherein a chain is shifted from sprocket to sprocket by an operator controlling a lever to position a camming surface to direct a guide pawl to tilt a segment of one sprocket whereby the tilted segment aligns with a nontilted sprocket during chain shifting.

A tool-positioning device is composed of a branch assembly in which each branch tube communicates with each branch flow string, an intermediate assembly provided with convergent tubes and a connecting assembly provided with a spline for guiding the connecting assembly with respect to one of the flow strings. An orientation and guiding member is interposed between the intermediate assembly and pumping means housed within a production tube. The orientation and guiding member has a slit which is or...

An improved rotating head having an inner barrel disposed within and rotatingly supported on an outer barrel wherein a rotary drive member is connected to the inner barrel. A kelly is extendable through the inner barrel and the rotary drive member is adapted to grippingly and sealingly engage the kelly so that rotation of the kelly causes rotation of the rotary drive member and the inner barrel connected thereto, the engagement between the rotary drive member and the kelly providing the sole sou...

The apparatus for making a substantially vertical slot in the ground, especially in a single operation in making a sealing or supporting wall, comprises a machine frame with a rectangular cross section guided in the slot in the ground with a plurality of guide surfaces and at least one driven cutting wheel positioned at the lower end of the machine frame. The machine frame and the cutting wheels have a width which correspond to the width of the slot in the ground within tolerances defined by the...

A self-locating seal assembly is shown for sealing between a well string and the bore of a surrounding well conduit, the surrounding conduit being provided with an internal recess for engagement by the seal assembly. A mandrel has an internal bore, an exterior, and a lower end. A seal body is carried about the mandrel and has an external seal region for engaging the interior bore of the surrounding well conduit and an internal seal region for engaging the mandrel exterior. The seal body provided...

A well packer is shown having an annular packing element surrounded on either side by axially shiftable annular shoulders. Extrusion preventing devices are located between each shoulder and the packing element to prevent extrusion of the packing material during use. The extrusion preventing devices include an outer split ring having a generally triangular cross-section defined by a cylindrical abutment surface for abutment with the outer conduit, a tapered sidewall engageable with one of the sho...

An asphalt paver, of the type having a power extendable floating screed, is provided with a power extendable auger-like material distribution mechanism, such that the width of the distribution mechanism can be varied with the width of the screed. The variable width distribution mechanism is structurally independent of the floating screed, so as not to impart its reaction forces to the screed. A variable width panel arrangement is incorporated into the power extendable distribution mechanism and ...

The leaf bascule bridge activated by a cable system, represents a movable structure which is adapted to opened so as to permit the passage of boats or vessels through the bridge. To achieve this purpose, the bascule bridge is provided with a fixed axis on trunnions attached to the bascule bridge structure, with a cable system for driving the bascule bridge, utilizing a counterweight to counterbalance the weight of the bascule bridge structure and a safety cable to guard against the unexpected up...

Device for a pole-shaped element (1), which is attached against a base (2) adjacent to a ground plane (3) in such a way, that it is released when made subject to a collision within a region adjacent to the base (2). One or a number of straps (4) are arranged extending between a first point of attachment adjacent to the upper portion of the pole-shaped element (1) and a second point of attachment in relation to the ground plane (3), adjacent to the base (2). When the pole-shaped element (1) is ma...

A trapezoidal cross section cog belt comprising a rubber body having longitudinally spaced inner cogs, a longitudinally extending tension resisting girdle and transversally extending reinforcement members in said cogs, said members having a bandular open shape adapted to undergo deformation in the longitudinal direction of the belt when the same is in use.