Abstract: An oil pump device for a chain saw comprises a drive unit having a drive shaft and a gear fixed to the drive shaft and meshing with a worm gear fixed to a power output shaft of an engine. The oil pump device also comprises a pump unit having a pump casing and a plunger rotatably and axially reciprocatably received in the pump casing and drivingly connected to the drive shaft. The drive unit and the pump unit being formed as separate components and are drivingly connected to each other through a slide joint which permits the plunger to axially displace relative to the drive shaft.

Abstract: A hydraulic pump of the rotary vane type comprises a first throttle bore and a second throttle bore disposed in parallel between a pressure chamber of the pump and a delivery passage, and a variable flow throttle valve is provided which is responsive to a difference between a vane back-up pressure and a pressure within the delivery passage to vary an opening degree of the first throttle bore.

Abstract: A scroll type compressor has bypass ports communicating with chambers which are being compressed. The bypass parts are bored in an end plate of a stationary scroll. A capacity control block contained inside a bypass passage has the bypass ports communicating with a suction chamber formed in a housing. A piston valve for opening and closing this bypass passage and control valve which senses a discharge pressure and a suction pressure and generates a control pressure for operating the piston valve is formed separately from the stationary scroll. The capacity control block is installed in close contact with the outer surface of the end plate of the stationary scroll, thus controlling the output capacity of the compressor in a range from 0% to 100%.

Abstract: A gear pump having a bypass valve within its port end cover is disclosed. The bypass valve is spring biased to open, pressure to close, rather than being pressure compensated, preventing hydraulic fluid from being "bled off" during the entire work cycle. A butterfly type structure is utilized for the dry valve which is attached to the inlet of the gear pump thus eliminating the need for a cumbersome device for actuating same.

Abstract: An adjustable eccentric mechanism for an orbiting rotary compressor comprising an eccentric, disposed within an orbiting roller, pivotally engaging a crankshaft and locking means for locking the eccentric to the crankshaft in a manner permitting adjustment of the eccentricity of the roller. A method of setting the eccentricity of an orbiting roller by swinging the roller around within the cylinder chamber into contact or a specified clearance with the sidewall, then locking the roller eccentric into place.

Abstract: A vane pump or a vane motor is here specified, having a variable displacement volume. The vane pump has a vane rotor and an annular stator that surrounds the rotor eccentrically and that is stabilized by means of a piston arrangement for adjusting the eccentricity that determines the displacement volume. The piston arrangement includes at least one pendulum piston that is acted upon by a pressure medium, the pendulum piston being guided in a sealed manner in a housing bore by a piston head that delimits a control space. To simplify the assembly and to decrease manufacturing costs while simultaneously improving the sealing action and increasing the peripheral life of the guide surfaces, plastic rings, which are composed of wear resistant, sliding material, or are prestressed radially, to guide the piston in the piston bore and to seal the control space are embedded, inserted or emplaced in the piston head.

Abstract: An oil injection type screw compressor includes an oil passage for circulating lubricating oil extending from an oil separator disposed in a discharge passage of a compressor main body through an oil cooler, oil filter and oil pump on the downstream side of the oil pump to parts requiring lubricating oil such as rotors, bearings, shaft sealing members within the compressor main body, the compressor comprising pressure switches for detecting a pressure of a suction passage as a low pressure side, and a pressure of the oil passage between the oil filter and the oil pump as a high pressure side, whereby starting the oil pump when the differential pressure between both the detected pressures is not more than the specified value.

Abstract: A method of molding complex shapes by injecting a plastics material resin into fibers (24, 32) within a mold (10, 34) wherein one or more galleries (22, 40) is provided in the mold communicating with the fibres, the gallery or galleries being so arranged as prevent substantial deformation of the fibres into them. The galleries may be arranged transverse to the length of some or all of the fibres and be sufficiently narrow to prevent deformation of the fibres into them; or the galleries may lie in the same general direction as the length of the fibres and channel inserts (42) provided with a series of transverse slots (44) are employed within the galleries to prevent fibres being pressed into the galleries.

Abstract: A concrete pipe making machine having a vibrating core and counter-rotating roller head is used to form a concrete pipe within a form. A concrete pipe reinforcing cage located within the form is held in spaced relation relative thereto with a plurality of cage positioners. Each cage positioner has a moveable blade connected to a piston and cylinder assembly operable to move the blade to a cage holding position and a blade retracted position out of engagement with the cage. The piston and cylinder assembly has a cylinder with a internal chamber having a rectangular cross section. A rectangular piston within the chamber is secured directly to the blade.

Abstract: The automatic trimmer apparatus of the present invention includes a base frame and trimming blade mounted on the base frame for trimming unwanted material from the meat product. A feed conveyor is situated forwardly of the trimming blade for transporting the meat product to the trimming blade. A feed roller is mounted on the base frame adjacent the trimming blade to receive the meat product transported by the feed conveyor and to advance the meat product into trimming engagement with the trimming blade. A press roller is mounted on the base frame for rotating the meat in trimming engagement with the trimming blade.

Abstract: A cyclically operated injection plastic molding machine which contains a device for moving a mold insert into and out of a mold is illustrated. When the mold is closed, the mold insert is moved into it; but, before the mold is opened, the insert is removed from it. The machine also contains an electric eye device which senses the motion of a movable finger which is caused to move by the motion of an injected molded part formed by the machine.

Abstract: A compression-resistant spacer is provided between the lower track of a hauler and the calibrator mounting platform of a calibrator or sizer in a extrusion line to prevent vibration of the calibrator and minimize wall thickness variations and surface markings of extruded profiles such as window profiles.

Abstract: An imaging apparatus produces a film of photohardened composition by exposing a layer of photohardenable composition to actinic radiation through a surface of a barrier transparent to the radiation and in contact with the composition at an interface therewith. An inhibition layer is created within the photohardenable composition in contact with the interface that inhibits photohardening of the composition within the inhibition layer during exposure, thereby precluding adhesion of any photohardened composition to the barrier.

Abstract: A burner structure and a method of operating a burner to reduce the pollutant emissions produced thereby are disclosed. Air and gas are premixed in a manner such that a substantially homogeneous mixture containing excess combustion air results. The velocity of the substantially homogeneous mixture is increased as it passes through the burner causing the "residence time" associated with the formation of the flame to be decreased, i.e., the combustion gases are in the reaction zone of the flame for a significantly shorter period of time, reducing the production of NO.sub.x. In order to prevent the flame from "lifting-off" the burner because of the high velocity of the substantially homogeneous air/gas mixture, flame stabilizing devices and/or a burner structure which provides flame stabilization are utilized resulting in the production of a high heat flux and low pollutant emissions.

Abstract: A burner control system periodically tests for and detects an out of range signal level from a flame sensor in the burner. When the system is in standby operation where no flame is present, the control system checks whether the flame signal level is within an abnormal range defined by a low margin level and a threshold level. When the system is in an operational phase where flame is expected, the system checks whether the flame signal level is within an abnormal range defined by a high margin level and the threshold level. Should either check detect the flame signal within an abnormal range, a signal is provided indicating this abnormal condition. Preferably, the abnormal condition is used to control the flashing of an indicator light, fast during standby phase if the flame signal level is too close to the threshold level and more slowly if the flame signal level is too close to the threshold level while flame is present. It is also possible to use two different lights for the indicators.

Abstract: The band delivery apparatus has two separate band stores, namely a band forward store (10.1) and a band return store (10.2). The two stores are constructed as chambers, which is controllable manner can receive a predetermined band material quantity. The filling and emptying of the stores is brought about by a coordinated cooperation of a buffer store separator (3) and the conveyor rollers (17.1, 17.2). The buffer separator (3) blocks the band passage upstream of the supply/exit openings of the two band stores (20.1, 20.2) and consequently leads to a bulging of the band in the storage areas. The filling of at least the band forward store is preferably assisted by a delivery means (11). The necessary band material quantity during prestorage can be precisely determined by means of sensors.

Abstract: This invention relates to an exhaust gas measuring device, in particular for the measurement of the oxygen content in the exhaust gas stream of an internal combustion engine, which device can be connected to an exhaust gas line, having a measuring device arranged in an insulation, to which measuring device a measuring probe is connected, which is led out of the insulation.

Abstract: A terminal coupling tool comprises a plurality of first fastening portions, a plurality of second fastening portions, and a receiving portion disposed on each of the second fastening portions. The receiving portion has an open end positioned correspondingly to an outer end of clamping tooth for allowing one end of the terminal intended to be coupled to be positioned securely in the receiving portion without the help of an operator's hand.

Abstract: An engine control method which can switch over the valve operating property of an engine in a step-wise manner according to the operating condition of the engine and which can control the slipping of the driven wheels through the use of a leaner air/fuel mixture so that it may not be undesirably affected by the deviations of the actual values of various parameters from the designed values of the parameters. Furthermore, a valve operating property is allowed to be switched over from a low speed condition to a high speed condition only when the output of the engine is not reduced as a result of the switch over.

Abstract: The leg exerciser is a simple device, preferably made from bent tubing, with a foot support at one extremity of the tubing and a loose fitting knee engaging pad. The knee itself serves as a pivot for the exercising of a leg. The bent tubing forms as L shaped set of parallel rods, between which the foot may be engaged, supported between the rods. A knee pad is engaged on the rods over the knee. There is a handle at the end of the L shape of the rod. The handle can be used with great leverage for easily exercising the leg pivoting on the knee. The leg exerciser can alternately be engaged to a shoe from leg brace for the same use. The leg exerciser is simple to construct, inexpensive, and light weight.

Abstract: Core biopsy needle units used with automated biopsy guns are disclosed. The needle units comprise an elongate solid needle having a notch formed adjacent to the end of the needle. A hub is securely attached to the other end of the needle. An elongate cannula is received over the notched end of the needle such that the needle slides longitudinally through the cannula. A second hub is securely attached to the first end of the cannula, and engagement means are formed in the hub on the needle. The hub on the needle and the second hub on the cannula are adapted to be received in respective receiver cavities of an automated biopsy gun, with the engagement means in the hub on the needle making firm, releasable, interlocking engagement with corresponding engagement means associated with the receiver cavity in which the hub on the needle is received.

Abstract: A front-wheel steering system, which has a clearance between a steering shaft and a pinion shaft so that the two shafts will be out of contact when the relative angular position of these shafts is within the range of the angle .theta..sub.1. A driving motor drives the pinion shaft 9 within the range of angle .theta.1 and a mechanical clutch 8 transmits transmitting the driving torque of the driving motor to the pinion shaft 9. This mechanical clutch 8 is designed to be disconnected by the driver's steering power when the relative angle has exceeded the angle .theta..sub.1.

Abstract: A heat exchanger for a refrigeration circuit includes a plurality of fluid tubes aligned in a parallel relationship with each other and corrugated fins disposed therebetween. A pair of header portions are connected with the ends of the fluid tubes. The header portions includes plate members which have a plurality of elongated holes for receiving the ends of the fluid tubes therein. Cup-shaped members are disposed in sealing contact with end surfaces of the plate members to cover the ends of the fluid tubes. With this construction, the refrigerant passageways can be securely maintained. Further, the core of a heat exchanger can be shaped to conform to the space available for mounting the heat exchanger, to thereby enhance the efficiency of the heat exchanger.

Abstract: A conveying section is engaged with works to be weighed to sequentially convey the works at predetermined intervals along a substantially arcuated path. An engagement releasing section sequentially releases engagement between the conveying section and one of the works at a predetermined region substantially equal to one of the predetermined intervals of convey midway along the arcuated path of the conveying section. A conveyor section is linearly arranged to oppose the predetermined region on the arcuated path on which engagement between the conveying section and the one of the works is released by the engagement releasing section. The conveyor section linearly and sequentially conveys the one of the works released from the conveying section. A weighing section sequentially measures weight of the one of the works while the one the works released from the conveying section is linearly conveyed by the conveyor section.

Abstract: A support for current conductor rails at an essentially double T-shaped beam girder is welded together of two mirror-symmetrical profiles. A support, carrying the current rails, surrounds the top flange of the beam girder (1) and rests with an angled clamping face (7) at an angled holder strap (4) of the top flange. The support (6) is held by U or V-shaped clamps (12) at the holder strap (4) of the top flange. This arrangement provides for a suitable attachment possibility for current conductor rails above the bottom flange of a double T-shaped beam girder.

Abstract: A coin selector includes a horizontal coin conveying unit for forcibly conveying a coin inserted through a coin insert slit in the horizontal direction while the coin is held between an opposing pair of endless belts. The horizontal coin conveying unit is slidably arranged in a housing of the coin selector, and moreover, the space defined by the opposing pair of endless belts is enlarged by turnably opening the opposing pair of endless belt about their one end. The upstream side of the horizontal coin conveying unit is covered with a cover, and a liquid collecting portion is attached to the cover so as to allow a liquid received through the coin insert slit to be quickly discharged outside of the coin selector.

Abstract: A container, such as a bucket, for containing tools of particulate material, such as mixed sand and cement, which has two leg members extending from its underside, the leg members being arranged to sit astride the apex of a pitched roof so that the container can sit stably on the roof apex. The container is useful for working on a roof, particularly when fitting the ridge tiles.

Abstract: A blind rivet feeding attachment for an automatic riveting machine having a riveting head and a drill mounted on a reciprocating shuttle comprises a rotating transfer arm for picking up a rivet from a supply tube and inserting it in the riveting head of the automatic riveting machine. While the riveting head is drilling a hole in the workpiece at a "work" position, a rivet clamp extracts a new rivet from the supply tube and retains it at the "pickup" position. After the drill has formed the hole, the shuttle moves the riveting head to the work position and installs a rivet in the hole. Rack and pinion gearing rotates the transfer arm towards the rivet clamp in response to the shuttle motion and engages the new rivet tangentially. After the riveting head has installed the rivet, the shuttle moves the riveting head to a "delivery" position, where the transfer arm inserts the new rivet into the riveting head.

Abstract: A hand truck holder apparatus (40) for releasably securing a hand truck (20) to a vehicle bumper (32) includes a bracket member (48) having a mounting plate (50) and a pair of flanges (52, 54) positioned on opposed sides of the mounting plate (50). Mounting means are coupled to the bracket member (48) for mounting the same to the vehicle and a support member (44) transversely mounted to the pair of flanges (52, 54) supports the hand truck (20) thereon. Moreover, a substantially resilient securing strap (46) is mounted to and transversely spans the bracket member (48), thereby securing the hand truck (20) to the bracket member (48). In another aspect, the mounting means include a plurality of sets of apertures (80) extending therethrough for releasably mounting the bracket member (48) to a plurality of vertical mounting positions relative to the bumper (32).

Abstract: In a device for opening pressed fiber bales and spinning material set up in rows along a bale supporting wall (12) by means of a milling device (5) accommodated in an arm casing (6) and having two parallel milling rollers (3,4) working on the surface (20) of the fiber bales (7). A suction hood is arranged above the milling rollers for sucking the loosened fibers off in an air flow. A suction opening (18), open towards the bale surface (20), is recessed between the milling rollers (3, 4) in the front wall (14) of the arm casing (6) facing the bale supporting wall (12) and a stripping device (26) abutting against the bale supporting wall (12), is arranged at the front wall (14) in the area of the suction opening (18).

Abstract: A panel fixture adapted to be inserted into a cavity formed in a panel, the panel fixture releasably receiving an accessory. The panel fixture can be mounted within a routed cavity in a panel or wall such that its faceplate can be substantially flush with the panel surface or wall surface to provide a convenient, randomly selected location for supporting an accessory such as a hook bracket or a shelf support bracket. The mounting of the panel fixture into the cavity simultaneously holds the panel against a wall structure. The faceplate has a slot located in an upper portion of the fixture. An accessory bracket to be inserted in the fixture may have a stepped upper plate part and a planar lower plate part and is mountable in/on the fixture with the stepped upper plate part of the accessory bracket inserted and confined in the slot of the fixture faceplate, and with the planar plate part of the accessory bracket fitting flat against the recessed planar surface of the body of the fixture.

Abstract: An expanding gate valve assembly comprising a gate, a stem for actuating the gate and floating segments movably mounted on opposite sides of the gate for movement relative to valve seats on a valve body. The valve seats on the valve body are inclined to the axis of the stem, and the segments are provided with correspondingly matching inclined surfaces. Movement of the segments is arrested by stops on the valve body, thereby making the segments expand laterally during closure The gate has a lower gate part having a through conduit which is alignable with a fluid flow passageway in the valve body in the open position, such lower gate part having tapered surfaces parallel to the incline of the valve seats to seal therewith and establish fluid tight communication between the through conduit of the gate and the fluid flow passageway.

Abstract: A tundish for molten metal having a front wall with an opening is provided. A plate with an opening is fitted into the opening in the front wall and retained therein. By replacing the plate with a plate with a plate having an opening at a different vertical level, the tundish can feed horizontal continuous casting molds of different levels.

Abstract: A drag reducer to be mounted on the rear face of a truck or other vehicle. It is comprised of an enclosed bag in the shape of a truncated cone with one or more elastic cord(s) encircling it. Air is introduced into the drag reducer upon forward motion of the vehicle via a tube, the open end of which is facing the direction of motion. As air pressure is increased in the drag reducer with increasing forward velocity the tension in the surface of the bag causes the elastic cord(s) to be extended allowing the drag reducer to reach its fully expanded shape. At slow driving speeds the elastic cord(s) contract and prevent the drag reducer from falling or being blown by cross winds over the rear signal lights or license plate and from touching the road in the case of larger more aerodynamically effective drag reducers.

Abstract: An imprinting mechanism includes a sheet tray and comprises a housing and a spring bias device within the housing. A sheet stack support is positioned within the housing and in contact with the spring bias, the spring bias forcing the sheet stack support towards a first position, the sheet stack support being forced (against the spring bias) to a second position when a stack of sheets is positioned thereon. A pivotally mounted indicator is positioned within the housing and includes first and second arm portions, a first portion being in contact with a surface of the sheet stack support and a second portion movable between visible and invisible locations, as viewed by a user. The first portion is movable about the pivot to position the second portion to the visible location when a predetermined size stack of sheets remain in the sheet stack support.

Abstract: A radially outward flow turbine having a rotor with nozzles which extend from an inner inlet passage to the rotor periphery with a substantially constant pressure drop per unit length of nozzle, with a first order surface continuity along the surface of each nozzle and with a nozzle profile which allows two-phase flow without substantial lateral acceleration according to the following formula: ##EQU1## The turbine is also illustrated with a second set of nozzles outwardly of the first set included in either the rotor or in a second contrarotating rotor. The rotor in either case vents steam to multiple steam turbine stages while the second set of nozzles receives saturated vapor. The steam turbine stage may be defined by either the first rotor and a stator or the first rotor and a contrarotating rotor.

Abstract: A nozzle is provided for discharging a combustible air and fuel mixture into the combustion chamber of a cyclonic combustor. The nozzle includes a centrally located air plenum and a plurality of passageways for discharging air from the plenum into the combustion chamber. The nozzle also includes a fuel jet system for discharging fuel into each air discharge passageway to mix with the combustion air passing therethrough.

Abstract: A cigarette lighter is disclosed having a spark producing wheel, a fuel delivery valve, and a fuel supply tank, all of which are mounted in a case and cooperate with a novel safety interlocking means. The interlock means includes a wheel interlock tooth for locking and unlocking the friction wheel which is actuated by a spring type handle mounted on one side face of the case. The wheel interlock tooth is attached to a coupling means which must be in an advanced position to allow the actuation of the fuel valve lever so that neither the fuel flow nor the spark may be activated unless the safety handle leaf spring is depressed.

Abstract: An apparatus (10) for liquifying tires is shown including a plurality of tire modules (12) holding tires which are immersed in and preheated by a slurry located in a tank (22). After preheating, the tire module (12) and tires held thereon are removed from the preheat tank (22) and are immersed in a slurry located in a high temperature tank (28). The temperature of the slurry in the high temperature tank (28) is sufficient to liquify the tires. As the tires liquify, the slurry produced is retained in the high temperature tank (28) to immerse further tires and also overflows from the high temperature tank (28) to the preheat tank (22) and then to a storage tank (36). The slurry from the storage tank (36) can be pumped to the burner (42) of the heat exchanger (48) for heating the slurry in the high temperature tank (28) or can be used for other uses.

Abstract: A vertical resistive combustion furnace having a vertically oriented combustion zone in which first and second coaxially aligned tubes depend. The first tube is open at one end and closed at the other. The second tube is open at one end and partially closed at the other end and is mounted within and spaced from the first tube with the space between the coaxial tubes defining a passage for combustion products produced from a sample of material to be analyzed, disposed in said second tube. The combustion products pass upwardly in the channel through the combustion zone of the furnace so that the combustion products are hot when they exit the furnace for analysis.

Abstract: A power plant with efficient emission control and high turbine inlet temperatures is disclosed. The power plant includes a combustor for the combustion of carbonaceous sulfur-bearing fuel. The combustion of this fuel produces a hot gas with SO.sub.x and NO.sub.x contaminants. This gas is conveyed to a refractory heat exchanger where some of the heat from the gas is transferred to a pressurized air stream. The gas is then conveyed to a fluidized bed reactor. The fluidized bed reactor includes a central chamber with a fluidized bed positioned at the base of the chamber. Heat exchangers are positioned within the fluidized bed. These heat exchangers preheat the pressurized air stream which is then conveyed to the refractory heat exchanger and later conveyed to a turbine assembly. The fluidized bed reactor also includes circulating particulate matter, such as CaO. Ammonia may also be injected into the fluidized bed reactor. When operating at a temperature of at least 1,500.degree. F.

Abstract: Oral compositions for the local administration of a therapeutic agent to a periodontal pocket of a patient for alleviating dental disease comprise a plurality of dry, discrete microparticles each of which comprise an effective amount of at least one therapeutic agent dispersed in a matrix comprising a biocompatible and biodegradable polymer. Apparatus and methods are also provided for the dispensing of the dry microparticles to the periodontal pocket whereby they become tacky and adhere to the involved tissue so as to induce long term therapeutic benefits.

Abstract: A clear rigid plastic syringe tip having a central water passageway and three arcuate section air passageways disposed circumferentially about the water passageway. A novel adaptor is used to mount the syringe tip to the handpiece body.

Abstract: A dental instrument has a stem which presents, besides helicoidal ramps providing helicoidal cutting edges, annular grooves of V-shaped cross-section and spaced apart. One of the faces of each of the grooves is perpendicular to the longitudinal axis of the instrument. Due to the grooves, the instrument can be used not only as a reamer, with a rotative movement, but also as a file, with a back and forth movement when the faces of the grooves produce a scraping effect on the wall of the root canal being treated.

Abstract: An ultrasonic dental handpiece having a thin, flexible, elongated abrasive tool attached thereto for removing calculus deposits from the surface of teeth. A thin, flexible abrasive tool having a specifically selected diameter is used in conjunction with an ultrasonic handpiece for the purpose of removing calculus from deep within a periodontal pocket without traumatizing the surrounding tissue and bone. The use of a diamond coated abrasive tool aids in tactually detecting fine calculus deposits deep below the gum line. An annular aperture surrounding the circumference of the abrasive tool is used to provide a fluid spray for washing away loosened calculus. The ease and efficiency of calculus removal is greatly enhanced.

Abstract: A tool for the tapping of a bone hole and installation of an implant in dentistry has a knob manually rotatable externally of a patient's mouth on one end of an arm and a bit, releasably secured on a sprocket, rotatable inside the patient's mouth in response to rotation of the knob. A chain connects the bit sprocket to a sprocket attached to the knob, so that the bit rotates about an axis parallel to, but laterally offset by the arm from, the axis of rotation of the knob. For bone tapping purposes, a tapping bit is used and a "T"-shaped handle attaches to the knob to increase the lever arm for torque application. For screwing implant components together or into the tapped bone, a screwing bit is used. A resilient elastomer sleeve is releasably stretched over the implant component and over the screwing bit for initial positioning. Multiple, interchangeable bits are provided to match different-sized implant components.

Abstract: An optical member for transmission of laser radiation, the fiber comprising a light transmitting element containing calcium fluoride.

Abstract: An improved dental post formed of a unitary, elongated metal post having a proximal portion and a distal portion, the distal portion being configured to be received in a prepared drill hole in a tooth, the proximal portion being configured to extend externally of a tooth to receive a dental device, such as a crown, thereon, the proximal portion having a porous surface to which dental device materials securely adhere, the porous surface preferably having interconnected interstices. In one embodiment the post distal portion is irregularly configured to thereby accept a crown having a highly contoured configuration.

Abstract: A composition for endodontically treating a root canal is provided. The composition uses a thermoset resin based material adapted for insertion into the root canal of a dental patient and an adhesive material suitable for maintaining the polymer based material in the root canal. Either one or both of the thermoset resin based material and the adhesive material is conductive. As a result, the dental practitioner is able to determine where the apex of the root canal is located by means of measuring the conductance between the thermoset resin based material and the oral mucosa and periodontal ligament. This facilitates the filling of the root canal with the polymer based material.

Abstract: A phantom for simulating a patient during an X-ray exam that involves introducing a high contrast material into the patient. The phantom comprises a base and a first contrast element. The first contrast element is disposed within the base and has an X-ray attenuation greater than that of the base. The contrast ratio of the first contrast element to the base is approximately 50. In one embodiment of the phantom, the first contrast element contains iodine. In another embodiment, the base has a shape which occupies the entire field of view of the X-ray exam and the first contrast element is positioned substantially in the center of the field of view. In yet another embodiment of the phantom, a second contrast element is disposed within the base and has a contrast ratio to the base of approximately 1.5.