An articulator for casts of a dental model correlates the casts with the condition to be redintegrated throughout a full range of occlusal and masticatory registration. The articulator includes an hinged two part flexible element, each of which parts is a mirror image of the other, or a hinged one part flexible element having like opposing halves. Each opposed end of either type of element supports a sphere to be positioned within a respective one of a cavity formed in each cast and adhesively s...

An electric rerailer provided with guide ways for guiding a motor-driven vehicle of a model railway onto a pair of rails, in which the surfaces of the guide ways are formed by electric conductors electrically isolated from each other and used respectively for the left and right wheels of the vehicle, and the conductors are capable of being electrically contacted with the rails for the left and right wheels respectively. The guide ways are formed on inclined or horizontal surfaces of the rerailer...

A model internal-combustion engine having a rotatable shaft driven by an engine, a propeller secured to said shaft, and a self-starting mechanism in the form of a cylindrical hub mounted coaxially on the shaft against the propeller and having at one end an axially extending drive element at its periphery by means of which it drives the propeller and ramp-defining walls adjacent a spring-engaging element at its other end, and a helically wound spring surrounding the shaft, anchored at one end to ...

A mounting cooperatively associated with the rear face of each cast of a pair of dental model casts interconnects one of opposed parts of an articulator to secure the articulator to the dental model. Each mounting includes at least one cast insertable locking member supporting one element of a ball and socket joint which joint is disposed intermediate the respective cast and the articulator.

This invention comprises a process for molding a three dimensional decorative article where cored out or raised portions extend to a depth of at least 0.6 centimeter, said process comprising generating electronically a line drawing of said article and electronically displaying the drawing; photographing said drawing to form a photographic transparency; positioning said transparency over a layer of a liquid photopolymer having a depth greater than 0.6 centimeter; exposing said photopolymer throug...

A small internal combustion engine especially--but not exclusively--for model aircraft is made at an extremely low cost. A crankcase and a fuel tank are made of two casted pieceparts which nest together. The two pieceparts include matching openings which are aligned to provide an air intake and a manifold leading from the fuel tank into the interior of the crankcase. A crankshaft is journaled to rotate within the crankcase. A connecting rod is made from a generally "Y" shaped leaf spring. The st...

A light source within a transparent hollow globe continually illuminates one half the globe to represent solar illumination. The light source is rotated about the north-south axis of the globe at the rate of one revolution per day and is concurrently oscillated about a second axis at the rate of one oscillation per orbit about the sun.

A robust model reference controller which supplies manipulated variables for controlling a multi-input multi-output process of the type which may not be modelled perfectly consists of a pre-compensator, a diagonal filter, and a post-compensator. The input signals to the robust model reference controller are first projected dynamically into decoupled signals by the pre-compensator. The diagonal filters then filter the decoupled signals individually. The filtered signals are projected back dynamic...

An improved engine mount for model airplanes which significantly increases usable engine power by reducing engine oscillation and thereby also engine power loss due to such oscillation and which greatly facilitates installation and removal of the engine. The mount comprises a relatively stiff mounting block substantially coaxial with the engine crankshaft rotation axis and extending between and rigidly secured to the rear end of the engine crankcase and an engine mounting wall or the like on the...

A dental model articulator 10, intended for use with a dental model 12 comprising a cast of a set of upper teeth, and a case of a set of lower teeth, comprises two parts 18 and 20 which are constituted by a strip 22 of a resiliently flexible material. The strip 22 has a region of reduced thickness to form a flexible hinge 26 about which the parts 18 and 20 can hinge flexibly relative to each other. Each part 18, 20 has a boss 34 formed integrally therewith, each boss 34 defining a socket 36. A p...