An apparatus for producing disilane through pyrolysis of monosilane, includes: a monosilane pyrolysis unit; a solid particle removal unit which removes solid particles generated in the pyrolysis unit; a condensing unit which liquefies and collects unreacted monosilane, and disilane and higher silanes with three (3) to seven (7) silicon atoms as pyrolysis products excluding hydrogen from a gas with the solid particles removed; a first separation unit which separates monosilane from a mixture of the liquefied unreacted monosilane, disilane and higher silanes; and a second separation unit which separates disilane and higher silanes from the mixture with the monosilane removed. In accordance with the present disclosure, disilane can be produced economically and efficiently with high purity through pyrolysis of monosilane.

A disclosed thermal treatment apparatus includes a supporting member where plural substrates are supported in the form of shelves; a reaction tube that accommodates the supporting member within the reaction tube, and is provided with plural gas supplying pipes arranged in a side part of the reaction tube, thereby allowing a gas to flow into the reaction tube through the plural gas supplying pipes; and a first heating part that heats the plural substrates supported by the supporting member accommodated within the reaction tube, wherein the first heating part includes a slit that extends from a bottom end to a top end of the first heating part and allows the plural gas supplying pipes to go therethrough, and wherein an entire inner surface, except for the slit, of the heating part faces the side part of the reaction tube.

The present disclosure provides an apparatus for manufacturing a single crystal silicon ingot having a dual crucible for silicon melting which can be reused due to a dual crucible structure. The apparatus includes a dual crucible for silicon melting, into which raw silicon is charged, a crucible heater heating the dual crucible to melt the raw silicon into molten silicon, a crucible drive unit controlling rotation and elevation of the dual crucible, and a pull-up drive unit disposed above the dual crucible and pulling up a seed crystal dipped in the molten silicon to produce a silicon ingot. The dual crucible has a container shape open at an upper side thereof, and includes a graphite crucible having an inclined surface connecting an inner bottom and an inner wall, and a quartz crucible inserted into the graphite crucible and receiving the raw silicon charged into the dual crucible.

Systems, methods and apparatus are provided through which in some implementations an expandable or adjustable snap-in cam or other friction device having a mechanically lockable drawer, shelf or divider in a cabinet, pantry, kitchen cupboard mount includes no screws or other permanent mounting.

A connecting apparatus for connecting two drawer wall parts which are intended to be arranged at a right angle includes at least one receiving part which has a receiving opening for receiving an end section of a first drawer wall part and has at least one insertion opening, a bracket which has at least two limbs which run substantially parallel, wherein the bracket can be pushed onto a web, which is arranged or formed on a second drawer wall part, in order to connect the first drawer wall part and the second drawer wall part, and wherein the at least two limbs of the bracket surround the web of the second drawer wall part, wherein a first limb of the bracket can be inserted into the insertion opening in the receiving part and connects the receiving part to the second drawer wall part in a positionally secure manner.

Storage apparatus configured to provide an external apparatus with logical storage area as data storage area, the storage apparatus having a physical storage medium configured to generate the logical storage area, and storage controller communicatively coupled to physical storage medium to control data input/output processing between the external apparatus and the logical storage area, wherein the storage controller includes circuit package including circuit board which implements predetermined function of storage controller and a circuit board case to accommodate the circuit board, plurality of cooling fan units that generate cooling air for cooling circuit component mounted on the circuit board of the circuit package, and a chassis having a structure for accommodating the circuit package and the cooling fan units, some of circuit packages are inserted to be accommodated in chassis from opening thereof and are arranged side by side across width direction of chassis.

A highly reliable vacuum heat insulating material having excellent processability, usability and heat insulating performance and a heat insulating box using the vacuum heat insulating material are provided. A vacuum heat insulating material related to the present invention includes: a core material structured by a laminated structure of an organic fiber assembly formed by forming an organic fiber into a sheet shape and cutting an end face with a predetermined length, and having a core material opening portion formed by a through hole or a notch with cutting; a gas-barrier outer cover material containing the core material inside, having a sealing portion for sealing surrounding of the sheet-shaped organic fiber assembly and surrounding of the core material opening portion, and hermetically sealing an inside with almost vacuum status by sealing the sealing portion; and an outer cover material opening portion provided at the outer cover material under a status in which the sealing portion provided at the surrounding of the sheet-shaped organic fiber assembly and the surrounding of the core material opening portion is sealed, being a through hole or a notch which is smaller than the core material opening portion with a sealed amount, and a long fiber being equal to or longer than a length of the sheet is used for the organic fiber.

A railway rail fastening apparatus has a baseplate for receiving a railway rail to be fastened thereto and baseplate securing elements for securing the baseplate to a baseplate seat area of a concrete railway foundation. The baseplate securing elements carry first and second fastening assemblies configured for location on the concrete rail foundation on opposite sides of the baseplate seat area. Each of the first and second fastening assemblies including fixing member having a first part that extends from the baseplate member for retention within the concrete rail foundation. Only the fixing member of one fastening assembly includes a screw-threaded fastener.

Railway rail fastening apparatus, for suspending a railway rail at discrete locations along its length above a rail foundation, comprises two rail suspending assemblies located when in use one on each side of the rail. Each assembly comprises an elastic member for supporting the head of the rail on one side thereof and a bracket for applying a lateral clamping force to the elastic member. The rail suspending assembly on one side of the rail is located such that the center line of the assembly is offset with respect to that of the rail suspending assembly on the other side of the rail by x mm along the longitudinal axis of the rail, where x is 50≧x>0 mm.

A method of making an electrical connection to a railroad rail includes fastening a wire bonding assembly to a railroad rail, the wire bonding assembly including first and second spaced apart washer plates contacting the rail and a metal bar supported by the washer plates. The metal bar is electrically connected with the rail with a first conductive lead contacting a selected point on the rail and a selected point on the metal bar. A second conductive lead is connected to another selected point on the metal bar for establishing an electrical connection to the rail from an electrical device.

An inflatable structure may be formed from a single piece of flexible film using a provided method of manufacturing. The inflatable structure may include quilting seals which divide the inflatable chamber. The inflatable structure may also include an external valve opening extending through multiple layers of the flexible film. The external valve opening may further be partially defined by edge portions of the flexible film formed by folding the flexible film. The external valve opening may be configured to align with an opening in a container or an inflation aperture in a pouch so that the inflatable structure can be inflated while inside the container/pouch. A corresponding inflation device fills the inflatable structure with air and may do so without requiring heat sealing or contact between the inflatable structure and outlet of the inflation device. A hinged plate apparatus may assist in directing air into the external valve opening.

A locking apparatus for a case and the case having the same are disclosed. In one embodiment, the locking apparatus includes an operating knob formed at an external surface of the case and a latch connected to the operating knob and configured to slide with respect to the case. The latch may include i) a body portion connected to the operating knob, ii) an opposite wall portion having opposite walls which extend from a first side of the body portion, iii) a hitch member formed on a second side of the body portion, wherein the first and second sides are opposing each other, and iv) a reinforcing member disposed between the opposite walls.

An apparatus for anchoring at least two graft ligaments within a longitudinal bone tunnel includes a longitudinal sleeve having at least two ligament-contacting surfaces located in lateral opposition to a sleeve inner lumen. The sleeve is configured for at least partial insertion into the bone tunnel with each graft ligament positioned laterally adjacent a different ligament-contacting surface and at least partially located between the bone tunnel and the sleeve. An actuating member has proximal and distal actuating member ends. An asymmetrically offset profile is defined by the sleeve and/or the actuating member. The asymmetrically offset profile has engagement thresholds. The actuating member is inserted into the sleeve to cause frictional engagement of each graft ligament with both the bone tunnel and at least one ligament-contacting surface, the frictional engagement of each graft ligament being temporally spaced apart from the frictional engagement of at least one other graft ligament.

A door opening preventing apparatus for a vehicle includes an outer door handle mounted on an outer surface of a door panel, a door opening lever mounted on an interior of the door panel to angularly rotate and interlocking with the outer door handle when the outer door handle is opened, and a latch cable connected to the door opening lever, wherein a separate balance weight is disposed at an upper end of the door opening lever to contact the door opening lever, and the door opening lever is pushed by the balance weight outward due to a forward inertial force during a side collision of a vehicle, and only the balance weight is angularly rotated inward by a reverse inertial force.

Gear processing machine (4), such as a gear cutting or grinding machine, wherein a chamfering and/or deburring apparatus (2) and auxiliary spindle (10) are included on the same machine. A transfer mechanism (8) loads, unloads and transfers workpieces between a machining spindle (6) and the auxiliary spindle (10) thereby enabling simultaneous cutting and chamfering and/or deburring processes to be carried out. Via the auxiliary spindle, completed workpieces may be removed from the machine and blank workpieces may be loaded into the machine while another gear is being processed on the machine spindle thereby enhancing machine output and creating a more efficient operation.

A path display apparatus includes a first position command acquiring unit that acquires first position command for motors, a first position feedback acquiring unit that acquires first position feedback of each of the motors, a correction data acquiring unit that acquires correction data generated for each of the motors, a second position command calculating unit that subtracts the correction data from the first position command to calculate a second position command, a second position feedback calculating unit that subtracts the correction data from the first position feedback to calculate second position feedback, a command path display unit that displays a command path of the tip point of the tool, based on the second position command; and a feedback path display unit that displays a feedback path of the tip point of the tool, based on the second position feedback.

A rotary joint device includes attachment grooves formed at positions in an outer peripheral surface of an outer cylinder, each attachment groove being formed so as to straddle a pair of adjacent cylindrical blocks and so as to be exposed from the outer peripheral surface of the outer cylinder, each attachment groove having a bottom surface that is machined to form a flat surface in a state in which the cylindrical blocks are combined, and positioning blocks corresponding to the attachment grooves on a one-to-one basis and each having an attachment phase that is uniquely set to a corresponding one of the attachment grooves in the axial direction and in a circumferential direction of the outer cylinder, each positioning block having an attachment surface corresponding to the bottom surface of a corresponding one of the attachment grooves, the attachment surface being machined so as to form a flat surface.

A machining apparatus for grinding, milling, polishing or the like of a dental workpiece. The machining apparatus contains a machining tool, a housing to which the machining tool is mounted rotatably about an axis of rotation relative to the housing, and a holding device to which the housing is fixed. The housing is mounted yieldingly movably to the holding device in dependence on forces exerted on the machining tool.

A ram guiding apparatus 1 of a machine tool is incorporated in a portal type machine tool 2 and provided with a cross saddle 5 that is cross-like in shape, as seen in a side view of the machine tool 2, provided so as to be freely movable in the horizontal direction along a horizontal cross beam 4. The cross saddle 5 has a box 18, both upper and lower faces thereof being open, in a front side of a horizontal part, wherein a first linear guide 21, a second linear guide 22, and a third linear guide 23, respectively serving as linear guides in the box 18 for a ram vertical movement, guide the ram 9 so as to be freely movable only in the vertical direction.

An apparatus for forming a bend in a composite panel is provided. An angle and a radius bend are identified for a bend. A location of the bend in the composite panel is identified. A slot is cut having a curved flange in the composite panel at the identified location in a single pass through the composite panel with a tool, wherein the curved flange has a shape with a bend allowance width and a bend slot width. The bend allowance width is BA=2π*A/360, wherein BA is the bend allowance width, R is a corner radius, and A is a bend angle. The bend slot width is BS=BA−2K(R−T), wherein K is Tan(A/2) and T is a thickness of the composite panel.

A translocation-simulating loading apparatus for the gear grinding machine with the shaped grinding wheel is provided. The apparatus includes a load-receiving test piece disposed on the gear grinding machine with the shaped grinding wheel and a load-exerting component for use in loading simulation. The gear grinding machine enables linear movements along the X, Y, and Z axes, a rotary movement around the Y axis, a rotary movement C around the Z axis, and a rotary movement A around the X axis. An angle α is formed between the axis L of a ball seat of the load-exerting component and the X axis direction of a Y axis component and an angle formed between the normal line of a load receiving face a and the X direction of the coordinate system of the machine tool is α. A detection method for static stiffness distribution is provided.

A cooling assembly for a machine tool including at least first and second nozzle rings mounted on the spindle housing, respectively defining first and second coolant conduits and respectively including first and second pluralities of nozzles in fluid communication with the respective conduit. Each first nozzle is oriented with an outlet thereof directed toward a first machining zone containing cutting edges of at last one tool having a first length. Each second nozzle is oriented with an outlet thereof directed toward a second machining zone different from the first machining zone and containing the cutting edges of at least one tool having a second length.

A control apparatus C of a horizontal axis wind turbine apparatus WTG calculates the value en of a pitch angle command for each blade based on the rate of change ΨD of the azimuth angle Ψ of a Nacelle N and the rotor azimuth angle of the blades B1, B2 and B3, causes the rotor R to generated torque around the yaw axis by periodically controlling the angle change of the pitch angle of the blades B1, B2 and B3, and using that torque, controls the rate of change of the azimuth angle of the nacelle N. The value of that angle change is calculated as a value that increases as the inputted value of the rate of the change ΨD increases.

Chemical liquid injector 100 includes two piston driving mechanisms 130 each moving a piston of a syringe forward, main injection condition determining section 171 determining injection conditions for a chemical liquid in main injection, test injection condition determining section 172 determining injection conditions for the chemical liquid in test injection performed prior to the main injection to inject a smaller injection amount of the chemical liquid than that in the main injection, and control section 161 creating an injection protocol in accordance with the injection conditions determined by test injection condition determining section 171 and main injection condition determining section 172 such that the chemical liquid is injected in a series of operations in which the test injection is performed, then a preset injection suspension time is present, and subsequently the main injection is performed, and further controlling operation of piston driving mechanisms 130 in accordance with the injection protocol.

A mirror for the EUV wavelength range (1) having a layer arrangement (P) applied on a substrate (S), the layer arrangement having a periodic sequence of individual layers, where the periodic sequence has at least two individual layers—forming a period—composed respectively of silicon (Si) and ruthenium (Ru). Also disclosed are a projection objective for microlithography (2) including such a mirror, and a projection exposure apparatus for microlithography having such a projection objective (2).

A press plate that includes: a plate shaped press portion that is capable of resilient deformation; a first slit that is provided to a first wall portion of a support body with length direction along a first edge portion of the press portion, and that penetrates the first wall portion; second slits that are provided to a second wall portions of the support body with length direction along second edge portions of the press portion, and that penetrate the second wall portions; and a first corner portion slit that is provided straddling a corner portion between the first wall portion and the second wall portion and penetrating the corner portion, that is connected to the first slit, and that is disposed at a separation to the second slit.

An X-ray photography apparatus including: a turning arm that supports an X-ray generator and an X-ray detector which are opposed to each other so that the head of a patient can be interposed therebetween, and a moving mechanism that includes a turning part and a moving part. The turning part turns the turning arm about a turning axis with respect to the head. The moving part moves the turning arm relative to the head in a direction perpendicular to the turning axis. The X-ray photography apparatus also includes: an image processor that generates an X-ray image, a photographic region designation part that designates part of a row of teeth along a dental arch as a pseudo intraoral radiography region, and an X-ray forming mechanism that changes the irradiation direction in which the head is irradiated with an X-ray relative to the axial direction of the body axis of the patient.

An X-ray photography apparatus including: a turning arm that supports an X-ray generator and an X-ray detector while the X-ray generator and the X-ray detector are opposed to each other so that a head of a patient can be interposed therebetween; and a moving mechanism that turns the turning arm about a turning axis with respect to the head and moves the turning arm in a direction perpendicular to the turning axis with respect to the head. The X-ray photography apparatus further includes: an image processor that generates an X-ray image based on an electric signal output from the X-ray detector; and a photographic region designation receiving part that designates part of a row of teeth along a dental arch as a pseudo intraoral radiography region. The image processor generates plural tomographic images by applying convolution and filtered back projection to X-ray image data obtained by pseudo intraoral radiography.

A medical image processing apparatus according to an embodiment includes: an imaging unit configured to image an affected area in two directions using X-rays; a fluoroscopic image generating unit configured to generate two X-ray fluoroscopic images corresponding to the two directions, on a basis of imaging signals outputted from the imaging unit; a rendering image generating unit configured to project the affected area contained in three-dimensional image data acquired in advance, in two directions according to a same X-ray geometry as that used for imaging the X-ray fluoroscopic images, to thereby generate two affected area rendering images; and an image combining unit configured to combine the X-ray fluoroscopic images with the affected area rendering images for each corresponding direction, to thereby generate combined parallax images in two parallax directions corresponding to the two directions, and to output the two generated combined parallax images to a 3D display apparatus.

A power converter is configured to include an inverter which converts a DC output into an AC voltage of a predetermined frequency, and a high voltage generator which receives an output from output terminals of the inverter and boosts the output to a desired high DC voltage. The high voltage generator includes a transformer, and the primary windings of the transformer are connected to the output terminals of the inverter in parallel by conductive wires connected to both ends of each primary winding. Further, a current sensor is provided to detect a current flowing through each of the primary windings, and a control unit determines abnormalities of a path of the inverter and the primary windings on the basis of a value of the current sensor.

In a high-voltage apparatus according to this invention, a predetermined voltage is applied to a rotating anode after waiting until the number of rotations increases to such an extent that the rotating anode is not damaged. That is, X-rays of desired intensity are already outputted from a point of time when the voltage is applied to the rotating anode. Therefore, diagnosis can be performed immediately after the voltage is applied to the rotating anode. That is, unlike the prior art, there is no need to wait until X-ray intensity becomes suitable for diagnosis after X-ray emission is started, and there is no need to irradiate the patient with unnecessary X-rays. Therefore, the patient can be inhibited from being irradiated with excessive X-rays (with an improvement made in a response from when the operator gives instructions for starting fluoroscopy until emission of X-rays suitable for diagnosis).

In a construction having a radiation tube in an envelope filled with an insulating liquid, a radiation generating apparatus which realizes a miniaturization of the apparatus, an improvement of a withstanding voltage between the envelope and the radiation tube, and a decrease in attenuation amount of the radiation and a radiation imaging apparatus using the radiation generating apparatus are provided. The radiation generating apparatus has an envelope 12 having a first window 27 for transmitting the radiation, a radiation tube 14 enclosed in the envelope 12 and having a second window 19 for transmitting the radiation at a position in opposition to the first window 27, and an insulating liquid 13 filled between the envelope 12 and the radiation tube 14. A solid-state insulating member 28 is placed between the first window 27 and its periphery and the second window 19 and its periphery.

An adjusting method of an X-ray apparatus has a reflection structure, wherein assuming that one end plane of the reflection structure is an inlet port of the X-ray and the other end plane is an outlet port of the X-ray, a pitch of the reflection substrates at the outlet port is wider than that at the inlet port. When the X-ray source exists at a position where a glancing angle at the time when the X-ray enters the inlet port exceeds a critical angle, an intensity of the X-ray emitted from each passage is detected. On the basis of the detected X-ray intensity, a relative position of the X-ray source and the reflection structure is adjusted.

An imaging apparatus having a ring-shaped gantry is provided. The gantry has a rotor arrangement rotating therein and a radiation source as well as at least one radiation detector. The gantry has at least one gantry segment which can be detached from the ring shape to allow the gantry to be opened laterally. The gantry is arranged on a supporting structure so as to be movable in space. The supporting structure is a ceiling-mounted stand having at least two degrees of freedom of movement. The gantry has at least two radiation sources disposed offset by an angle on the rotor arrangement and associated with each of which is at least one radiation detector.

A method for producing an X-ray projection image of a body region of a patient using a desired spatial location of a central ray, includes positioning a pointing element relative to the patient indicating a location of a pointing line and causing the location of the pointing line to coincide with the desired central ray location. A pointing line location and a central ray location currently set on an X-ray machine are recorded. A measure for deviation between the pointing line and the currently set central ray location is determined and used to set the desired central ray location. A medical apparatus includes an X-ray machine taking an X-ray projection image along a central ray, a pointing element indicating a pointing line, an acquisition unit detecting the pointing line location and the currently set central ray location, and a control and evaluation unit implementing software carrying out the method.

To provide an X-ray imaging apparatus capable of easily adjusting the sensitivity or capable of easily extracting the amount of refraction of X-rays. An X-ray imaging apparatus irradiating an object to be measured with an X-ray beam from an X-ray source that generates X-rays of a first energy and X-rays of a second energy different from the first energy to measure an image of the object to be measured includes an attenuator and a detector. The attenuator attenuates the X-ray beam transmitted through the object to be measured and is configured so as to vary the amount of attenuation of the X-rays depending on a position on which the X-ray beam is incident. The detector detects the X-ray beam transmitted through the attenuator and is configured so as to detect the X-rays of the first energy and the second energy.

The present disclosure relates to an electric field emission x-ray tube apparatus equipped with a built-in getter, and more particularly, to an electric field emission x-ray tube apparatus equipped with a built-in getter that makes it possible to reduce the size of an x-ray tube by forming a stacked structure, with electric insulation and predetermined gaps maintained for each electrode, by manufacturing an x-ray tube having a stacked structure by inserting insulating spacers (for example, ceramic) between an exhausting port, a cathode, a gate, a focusing electrode, and an anode and bonding them with an adhesive substance, and then inserting a spacer between a field emitter on a cathode substrate and a gate hole connected with a gate electrode.

Method for limiting an X-ray beam, wherein the X-ray beam is limited by a limiting unit comprising a couple of blades approaching each other or moving away from each other to adjust the width of a space between the blades the two blades being driven by an actuator (12) linked to both blades. The position of a symmetry axis (S) of the space between the blades is set in a shifting step by changing the distance between the blades and by impeding the motion of one blade in comparison with the motion of the other blade resulting in an asymmetric motion of the blades with respect to an initial position of the symmetry axis (S). The desired width (W) of the space between the blades is set in an adjustment step by an unimpeded symmetric motion of the blades with respect to the position of the symmetry axis (S) set in the shifting step.

A tridimensional modeling apparatus, system and kit is for representing an exploration network. The apparatus, system and kit include a transparent hollow cube with six plane surfaces for representing an enclosed volume, a plurality of perforations on at least two of the six plane surfaces and indicia around each opening for marking polar coordinates and orientation. The apparatus, system and kit further include a plurality of transparent rods for representing exploration channels. The plurality of perforations on the cube are arranged for receiving rods for tridimensional modeling of the exploration network and each rod is inserted into an opening with an angle and a depth, thereby resulting in a visual representation of the exploration network within the represented volume.

A method for selectively applying a reflectance modifying agent (RMA) to an area of skin, the method comprising receiving an image of the area of skin, identifying, using the image, a nominated point within the area of skin, determining an actual reflectance of the nominated point, applying an edge protection technique based on the image to generate one or more outputs, determining a desired reflectance of the nominated point based on the one or more outputs, calculating an amount of RMA to be applied based on the output, and determining whether to apply the RMA to the area of skin based on the amount of RMA.

Models, kits and methods useful in the demonstration of sialendoscopy devices and techniques are described. An exemplary demonstration apparatus comprises a support structure, an insert structure contacting the support structure, and a duct structure contacting the insert structure. The insert structure has a top surface defining a first opening and a bottom surface defining a second opening, and defines a channel with a first end in communication with the first opening and a second end in communication with the second opening. The duct structure comprises an elongate tubular member and has a first end in fluid communication with the first opening of the insert member, a second end, and defines a lumen extending from the first end to the second end. A portion of the duct structure is releasably disposed within the channel defined by the insert structure.

Information technology tools can be provided to manage access by a plurality of attendees through a network to a presentation. Each of the attendees is registered with an associated content access status, and presentation data for the presentation is provided to a registered attendee based on the particular content access status of the registered attendee.

An image display apparatus includes a communication unit to communicate with information processing apparatuses; an image synthesizing unit to synthesize a multi-segmented screen image composed of screen images of the information processing apparatuses; a projection unit to project the multi-segmented screen image onto a screen; a functional mode management unit to control switching between a normal projection mode and a multi-segmented screen operation mode; an image capture device to capture the multi-segmented screen image and a hand movement of an operator when switched to the multi-segmented screen operation mode; a designated screen image recognition unit to detect a hand movement of the operator based on the image captured by the image capture device, and to recognize a screen image designated as an active-target image; and a signal control unit to transmit a request of image data transmission to an information processing apparatus corresponding to the designated active-target image.

A method of providing a user with an extra-terrestrial somatosensory experience includes equipping the user with an underwater breathing apparatus, having the user occupy an underwater environment, such environment providing buoyancy to the user, and while the user occupies the underwater environment, using a computer-implemented virtual reality system to present to the user a virtual reality environment modeling an extra-terrestrial setting. The virtual reality system inhibits visual perception by the user of items outside of the virtual reality environment so that the user experiences the virtual reality environment under a buoyancy condition provided by the underwater environment. The buoyancy condition enhances the experience of the virtual reality environment.

An educational apparatus for educating, testing and entertaining individuals includes a rotatable spherical element, a planar support structure and a plurality of rollers for supporting the spherical element for rotational movement. The planar support structure defines an elevated planar surface with a circular opening therein. The rotatable rollers are hingedly mounted to the planar support structure around the opening for supporting the spherical element with a majority of the spherical element above the level of the planar support structure. A fixed element is fixed to the spherical element and a magnetic complimentary element is disposed adjacent the spherical element for contact by the fixed element.