215results about "Lab clamping means" patented technology

The invention relates to the technical field of medical cell culture, and discloses a medical experiment cell culture device which comprises a culture box, an electric push rod is fixedly connected to the lower surface of the culture box, a supporting plate is fixedly connected to the output end of the electric push rod, and a first connecting column is fixedly connected to the outer wall of the supporting plate; a first partition plate is fixedly connected to the inner wall of the incubator, a sliding groove is formed in the first partition plate, the outer wall of the first connecting column is slidably connected to the inner wall of the sliding groove, and a movable frame is rotatably connected to the outer wall of the first connecting column. The electric push rod is started to drive the supporting plate to move up and down, and then the connecting column drives the moving frame to move synchronously. The movable frame drives the transmission plate to move upwards, the frame plates at the two ends are pulled or pushed to move relatively through the fixing columns, then the closing plate is driven to be opened and closed, meanwhile, the placing frame can be moved into a test box or stored into a culture box, operation convenience and efficiency are improved, and the risk that the culture environment is polluted by manual taking is avoided.

The invention relates to the technical field of cleaning equipment, in particular to an underwater cavitation jet observation experiment device and method based on a triangular reflector, and the device comprises a jet control device, an impact observation device, a plurality of light source assemblies and a high-speed camera. The spraying control device comprises a nozzle, and external high-pressure water flow is sprayed out downwards from the nozzle after passing through the pump pipe; the impact observation device comprises a clamping device. The clamping device comprises a triangular prism reflector and a support used for placing the triangular prism reflector. A shot picture of the high-speed camera can simultaneously comprise a free jet flow area and a jet flow impact area reflected by the triangular prism reflector. According to the double-angle free cavitation jet flow observation device, the three-edged reflector is utilized, cavitation flow evolution of a free jet flow area of cavitation jet flow and a jet flow impact area reflected by the three-edged reflector can be observed at the same time, and double-angle free cavitation jet flow observation is achieved.

The invention discloses a pioglitazone hydrochloride sampling device and a use method thereof, and relates to the technical field of medicine sampling, the pioglitazone hydrochloride sampling device comprises a sampling mechanism and lifting fixing rods mounted around the bottom of the sampling mechanism, a fixing structure is arranged at the bottom of the sampling mechanism, beaker fixing seats are symmetrically mounted on one side of the top of the fixing structure, and the beaker fixing seats are symmetrically mounted on the bottom of the sampling mechanism. The sampling mechanism comprises a horizontal moving support, a horizontal moving motor is fixedly mounted on one side of the horizontal moving support, a horizontal threaded rod is fixedly connected to the output end of the horizontal moving motor, a horizontal threaded sleeve is in threaded connection to the outer side of the horizontal threaded rod, and an electric telescopic rod is fixedly mounted at the bottom of the horizontal threaded sleeve. The pioglitazone hydrochloride white crystal powder can be clamped through the sampling tube and the clamping hopper, and meanwhile, the pioglitazone hydrochloride and a corresponding reagent can be mixed to form a flowing sample, so that the pioglitazone hydrochloride can be conveniently detected.

The invention discloses a device and method for detecting saturation pressure through a near-infrared technology, and relates to the field of fluid saturation pressure detection. The device for detecting the saturation pressure through the near-infrared technology comprises a moving unit, a storage unit and a detecting unit, wherein the storage unit moves through the moving unit; the detection unit comprises a detection frame, a pressure adjusting mechanism, a clamping mechanism and an observation mechanism. According to the device and method for detecting the saturation pressure through the near-infrared technology, when the device is used, the output end of a driving air cylinder stretches, so that a clamping mechanism automatically clamps a storage unit, after clamping is completed, a pressure adjusting mechanism automatically completes gas circuit connection with the storage unit, an observation mechanism can be automatically in place and prepare for observation, and after detection is completed, the storage unit can be automatically adjusted. Along with the contraction of the output end of the driving cylinder, the clamping mechanism and the pressure adjusting mechanism are separated successively, then the observation mechanism is reset, and the moving unit automatically replaces the storage unit, so that the whole detection process is full-automatic, more convenient and time-saving.

Systems and methods for enhanced film sample gripping solutions are provided. An apparatus for processing a thin film sample may include a sample holder configured to engage the thin film sample, where the sample holder includes one or more holding members configured to receive the thin film sample in a flat position relative to the sample holder, and one or more securing members configured to secure the one or more holding members to the one or more holding members. The one or more securing members are configured to securely maintain the film sample in a flat position during manipulation of the sample holder. The sample holder may include one or more apertures between the one or more fixing members that enable access to both sides of the thin film sample at two or more locations on the thin film sample. The sample holder may include a width adjustment component configured to allow adaptation to different sample widths.

A gripper for moving a microtiter plate (190) using a robot arm (100) comprises a finger bodies (310), finger cantilevers (330), and resilient strips (370) so as to accommodate for inacurracies of the robot arm (100). The invention also relates to a method for moving a microtiter plate (190) with a robot arm (100) with improved reliability comprises the use of said gripper comprising two fingers (300) comprises independent of the other finger (300) a primary element chosen from i) a protrusion and ii) a cut-out capable of receiving the protrusion, and the MTP (190) comprising a secondary element that is the other of the primary element, and grabbing the plate (335) such that the primary and secondary element engage.

The invention belongs to the technical field of viscosity detection, and discloses a coating viscosity detection adjusting device which comprises a base, a mounting rod fixed at the top end of the base, a viscosity measuring instrument fixed at the top end of the mounting rod, a lifting mechanism fixed at the top end of the base, and a clamping mechanism mounted at the top end of the lifting mechanism. Through cooperation of structures such as a supporting seat, a first supporting rod and a first connecting rod, the device can start a servo motor to drive a screw rod to rotate when the height of a to-be-tested sample needs to be adjusted, so that the screw rod drives a second connecting seat to move; a first connecting rod and a second connecting rod are contracted or unfolded by changing the position of a second connecting seat, and a third connecting rod and a fourth connecting rod at the top end are synchronously folded at the same angle, so that the heights of a top-end top plate and a to-be-tested sample at the top end of the top plate are changed, and the to-be-tested sample is lifted; therefore, the purpose of improving the detection efficiency by quickly adjusting the height of the sample to be detected by the device is achieved.

The invention belongs to the technical field of glue viscosity testing, and particularly relates to a novel glue viscosity testing device which comprises a testing box, a circular truncated cone, a pushing clamping mechanism and a viscosity testing mechanism, and a temperature sensing assembly is arranged in the testing box; the circular truncated cone is arranged in the test box, a plurality of hole bodies are formed in the circular truncated cone, and a measuring cylinder is arranged in each hole body; the plurality of groups of pushing clamping mechanisms are positioned in the plurality of hole bodies and are used for clamping the plurality of measuring cylinders; the viscosity testing mechanism is arranged in the testing box and is used for testing the viscosity of the glue in the plurality of measuring cylinders; according to the glue viscosity testing device disclosed by the invention, the accuracy of testing the viscosity of glue in the measuring cylinders cannot be reduced due to the influence of the external environment; the accuracy and the high efficiency of batch testing of different or the same type of glue by the viscosity testing mechanism can be improved.

The invention discloses an intelligent glassware storage cabinet with recognition, classification and detection functions, and relates to the technical field of experimental facilities, the intelligent glassware storage cabinet comprises a glassware storage unit, a recognition and detection unit, an object taking and conveying unit and a control unit, and the glassware storage unit is installed in a storage cabinet body. The profiling groove of the memory sponge lining of the glass instrument storage unit is matched with instruments of the same type and multiple specifications, the pressing assembly achieves dynamic pressing through the micromotor and the pressure sensor, and the complexity of manually replacing a mold is avoided. The recognition and detection unit fuses a visual camera and a four-way ultrasonic detection module, accurate judgment of instrument types is achieved through visual recognition, an ultrasonic probe scans the interior of the instrument from the front, back, left and right faces, and hidden damage such as microcracks can be detected. The object taking conveying unit conveying belt achieves efficient linkage of a storage area and an object taking area, the object taking time of a single instrument is greatly shortened, the concentrated object taking efficiency of instruments of multiple specifications is improved, and the wrong taking rate is reduced.

The invention discloses an intelligent underground water quality monitoring device and method, and relates to the technical field of water quality monitoring, the intelligent underground water quality monitoring device comprises a shell and a draw-off pump, a connecting column is mounted on the draw-off pump, and a supporting assembly is arranged on the outer side of the connecting column; the supporting assembly comprises a sleeve shell, an electric push rod, a movable ring, a sliding block, a supporting rod, a limiting rod and a contact block, the sleeve shell is installed on the outer side of the connecting column, and the electric push rod is installed on the outer surface of the sleeve shell through a support. The contact block extrudes the inner wall of the vertical shaft, the device is stably fixed in the vertical shaft and adapts to vertical shafts of different sizes, data accuracy and stability are guaranteed, meanwhile, the connecting column and the sleeve shell are matched through the rotating ring, the first spring and the fixing bead, flexible rotation can be achieved, the direction of the draw-off pump can be adjusted according to the underground water flow direction, the turbofan directly faces the water flow, and the flow speed monitoring accuracy is improved.

The invention relates to a detection device and a detection method of an air filter, which are applied to the field of quality detection, during detection, a lead screw is matched with a detection piece, the integrity of a filter element is pre-detected through wind speed uniformity, and then a smoke dust test is started; detecting whether nodes which are suddenly increased appear or not by using a movable detection piece so as to judge whether the filter element has non-penetrating cracks or not; after detection, automatic cleaning is achieved through a dust collector and a rotatable sealing plate, an electric extension rod is adopted for adjusting an eccentric sealing plate for dynamic sealing compensation according to filters of different sizes, the device further comprises a stirring piece for accelerating smoke flocculation and sedimentation, and a detection control system achieves automatic operation; the problems of damage interference, residual smoke influence, poor size adaptability and the like in traditional detection are effectively solved, and the detection precision and efficiency are remarkably improved.

To provide a laboratory system for monitoring a reference point of a laboratory device.SOLUTION: A laboratory system comprises a first laboratory device comprising a first reference point, a second laboratory device comprising a second reference point, and a coupling element. The coupling element couples the first reference point and the second reference point. The coupling element comprises a detectable part adapted to be moved between a starting position and at least one detection position when a relative position of the first reference point and the second reference point to each other changes. The laboratory system further comprises a sensor configured to detect the detectable part of the coupling element in the at least one detection position. In addition, a method of operating the laboratory system as described is disclosed.SELECTED DRAWING: Figure 1A

The application discloses a slice rack, which comprises a slice rack body, a plurality of slice grooves are arranged on the slice rack body, a horizontal rectangular coordinate system is arranged and comprises an X direction and a Y direction, two opposite sides of the X direction are arranged as a first X direction side and a second X direction side, two opposite sides of the Y direction are arranged as a first Y direction side and a second Y direction side, a clamp jaw is arranged on the first Y direction side and the second Y direction side in each slice groove, one end of the clamp jaw is a connecting end connected with the slice rack body, the connecting end of the two clamp jaws in each slice groove is located on the first X direction side of the X direction in the slice groove, the other end of the clamp jaw is a free end and faces the second X direction side of the slice groove, and the clamp jaw can be bent and deformed around the connecting end of the clamp jaw. The slice rack has a simple structure, can be integrally formed by molding, is convenient to install the slice, and is convenient, fast and reliable in slice installation.

The application belongs to the technical field of RNA extraction devices, and particularly relates to an ep tube rack for RNA extraction, which comprises an ep tube rack body, a controller, a placing hole, a sucking assembly and a shaking assembly. A plurality of rows of placing holes with different specifications are formed in the ep tube rack body. The sucking assembly comprises a clamping ring, a fixing frame, a fixing column and a stabilizing frame. The fixing frame is fixed to one side of the front end of the ep tube rack body. The fixing columns are rotatably connected to the adjacent surfaces on the upper ends of the two fixing frames, and the fixing columns are damping shafts. The clamping ring is fixed between the two fixing columns. The stabilizing frame is fixed to the middle of the front end of the ep tube rack body. The application solves the problem that if the experimenter shakes hands, the upper layer of colorless water phase is easily transferred to a new ep tube after centrifugation, which can cause experimental failure.

To provide a suitable locking assembly for a measuring system.SOLUTION: The present disclosure is directed in one aspect to a lock assembly for securing a sample tube assembly to a sample manifold of a measurement system. The locking assembly includes a ramp block having one or more slots defined therein and configured to at least partially receive a portion of a sample tube assembly. The ramp block also includes a plurality of surface features defined therealong and configured to engage and move the sample tube assemblies toward and into engagement with the sample manifold. The lamp block is further movable between a plurality of positions, including an open position for allowing the sample tube assemblies to be received through the one or more slots or openings, and a closed position that substantially seals the sample tube assemblies against or within the sample manifold. Other aspects are also described.SELECTED DRAWING: Figure 1

The invention discloses a fixing clamp and a clamping method for a silicon carbide crucible, and relates to the technical field of crucible clamping. The device comprises a power-assisted mechanical arm, a clamping assembly and a detecting and cleaning assembly, before a crucible is clamped, a rotary mounting plate moves, a cleaning brush and a supporting round rod on one side of the rotary mounting plate make contact with an elastic clamping plate, the elastic clamping plate moves in the direction close to the crucible to drive the rotary mounting plate to move, and the crucible is clamped; the cleaning brush on the other side of the rotating mounting plate and the supporting round rod make contact with the surface of the crucible, the elastic clamping plate stops moving, at the moment, the elastic clamping plate is a bent arc-shaped plate, the rotating mounting plate moves in the side face direction of the elastic clamping plate, and the rotating mounting plate drives the cleaning brush to move; the cleaning brushes on the two sides of the rotating mounting plate are used for cleaning the side face of the elastic clamping plate and the surface of the portion, making contact with the elastic clamping plate, of the crucible, and impurity particles are prevented from being attached to the side face of the elastic clamping plate and the surface of the crucible and scratching the crucible during clamping.

A robotic liquid handling system may be provided comprising a robotic arm and a controller configured to control the robotic arm to position and operate the robotic arm in a workspace of the robotic liquid handling system. The controller may be configured to, as part of a liquid handling task, control the robotic arm to open a reagent reservoir, wherein the reagent reservoir has an opening which is sealed by a foil. The controller may be configured to control the robotic arm to open the foil by controlling the robotic arm to, using a cutting tip (260), cut at least two flaps in the foil, and using a blunt protrusion, push the at least two flaps downwards into the reagent reservoir to clear at least part of the opening of the reagent reservoir. Further aspects of the invention relate to a computer-implemented method for controlling a robotic arm and to an opening tool (200) comprising the cutting tip and the blunt protrusion.

The invention discloses an automatic control chemical experiment reaction device which comprises a back plate, a clamping assembly, a stirring assembly and an injection thruster, the clamping assembly is fixedly connected to the back plate, the stirring assembly is placed on the front side of the back plate, the position of the stirring assembly is matched with that of the clamping assembly, and the injection thruster is placed on one side of the back plate. A driver and a controller which are fixedly connected with the back plate are arranged on the back plate, the controller is in electric signal connection with the driver, and the driver is in electric signal connection with the clamping assembly, the stirring assembly and the injection propeller; according to the device, by adopting a modular motor driving system, a plurality of assemblies with different functions are coordinated and dispatched, so that the steps of automatic clamping, heating and stirring, reagent injection and the like of a reaction container are sequentially completed by each assembly according to a preset program, the defects existing in manual operation in the whole process are greatly reduced, and the production efficiency is improved. A large amount of time can be saved, and meanwhile the implementation efficiency and repeatability are indirectly improved.

The invention discloses a thermomechanical analyzer, and relates to the technical field of thermomechanical analys.The thermomechanical analyzer comprises a base, a lifting assembly, a first testing mechanism, a second testing mechanism, a clamping mechanism and a furnace body, the lifting assembly is installed on the back face of the base, the first testing mechanism is installed at the top of the lifting assembly, and the second testing mechanism is used for annular shooting of a sample; the clamping mechanism is installed at the bottom of the first testing mechanism, and the furnace body is installed in the middle of the base. The arrangement mode that the first testing mechanism, the second testing mechanism and the clamping mechanism are matched is utilized, so that the clamping mechanism can conduct point contact of different degrees according to the shapes of different samples, and the influence of the clamp on the temperature of the samples can be reduced; the sample can be subjected to mechanical pressurization testing and thermal expansion shooting comparison by the first testing mechanism and the second testing mechanism, so that the material performance of the sample can be conveniently and accurately tested, and the furnace body can conveniently perform thermal method testing on the samples with different shapes.

The invention relates to the technical field of incubation devices, and discloses a detection sample incubation device and method.The detection sample incubation device comprises a base and a water tank, a protective fence is fixedly installed on the periphery of the top of the base, the water tank is fixedly installed in the middle of the top of the base, and a heat preservation fence is fixedly installed on the periphery of the exterior of the water tank; a plurality of incubation spacing frames are arranged in the water tank in a linear array, and a plurality of flow guide holes penetrating through the outer surface of each incubation spacing frame are formed in the two sides of the incubation spacing frame. By arranging the clamping assembly, the clamping force can be dynamically adjusted according to real-time deformation of the incubation barrel, when the incubation barrel expands or shrinks due to temperature change, the clamping assembly keeps constant and flexible clamping force, and stress concentration or extrusion fracture caused by fixing a clamping groove is avoided.

The application discloses a kind of quick temperature change damp heat test device, belong to temperature change damp heat test technical field, including test box, the bottom wall of the test box is slidably installed with placing plate, the bottom wall of the test box is rotatably installed with annular plate, the top wall of the annular plate is fixedly installed with mounting ring, the top wall of the mounting ring is uniformly fixedly installed with gas rod.This scheme passes impeller, in the process of air flow flow direction annular groove will blow impeller rotation, in the process of impeller rotation annular plate is driven to rotate, then in the process of annular plate rotation through mounting ring gas rod is driven to rotate, at the same time, when airflow passes through communication pipe, airflow will flow to gas tank through communication pipe, and flow to vertical groove through gas tank, then blow to the product to be measured through the air hole on vertical groove, so that the efficiency of the product to be tested can be improved uniformly heated, cold and wet, improve the efficiency and accuracy of test.

To provide a method for handling an in-vitro diagnostic (IVD) container, such as sample tubes or reagent cartridges, in a laboratory.SOLUTION: An automated method for handling an in-vitro diagnostic IVD container (30) in an IVD laboratory (1) is proposed. The method comprises at least steps of measuring at least one physical quantity of an IVD container (30), storing the at least one physical quantity in a read-writable data carrier (50) attached to the IVD container (30), and retrieving the at least one physical quantity from the read-writable data carrier (50) attached to the IVD container (30).SELECTED DRAWING: Figure 2

The present invention relates to a device for precise quantitative pipetting and liquid dispensing, which comprises a liquid processing module and a quantitative loop liquid sampling module. The liquid processing module includes a sampling needle, a lifting motor, a rotating motor and a centering mechanism. The centering mechanism is used for placing a liquid container. The sampling needle sucks the solution from the liquid container. The lifting motor controls the up-and-down movement of the sampling needle through a lead screw, and the rotating motor controls the horizontal movement of the sampling needle through a swing arm. The quantitative loop liquid sampling module includes two switching valves and a plurality of quantitative loops. A plurality of outlets of the first switching valve are respectively connected to a clean air source and a plurality of quantitative loops, and the inlet is connected to the sampling needle. A plurality of outlets of the second switching valve are respectively connected to a first discharge port and a plurality of quantitative loops, and the inlet is connected in parallel to a liquid pump and a clean air source. The inlet of the cleaning pool is connected to a cleaning liquid pipeline. The inlet of the drying pool is connected to a clean air source. By switching through the switching valve and the conversion of the sampling needle among the liquid container, the cleaning pool and the drying pool, quantitative sampling, cleaning of each passage, liquid discharge and drying are realized.

The invention relates to the technical field of test tube racks, in particular to a test tube movement monitoring method and a test tube bearing device.The test tube movement monitoring method comprises the steps that a clamping position is selected, a test tube is clamped through the test tube bearing device, movement influence parameters of the test tube are obtained, whether solid matter exists or not is judged, and if not, a first speed is selected to move the test tube; if yes, whether the distance between the solid and the liquid level is larger than a preset distance or not is further judged, otherwise, a risk characterization parameter is determined according to the distance between the solid and the liquid level and the viscosity of the reagent, and a corresponding movement speed is selected as the movement speed of the test tube bearing device in a preset speed interval according to the risk characterization parameter; if yes, selecting a second speed as the moving speed of the test tube bearing device, and finally moving the test tube bearing device to a specified position at the determined moving speed; the problems that due to the fact that the moving speed is too high, solid matter in a reagent is attached to the test tube wall due to liquid level fluctuation, reagent quality is affected, and test tube cleaning difficulty is increased can be effectively solved.

The invention relates to the technical field of cell detection, and discloses an immune cell detector and a detection method.The immune cell detector comprises a reaction disc, a plurality of clamping frames are arranged on the reaction disc in a circumferential array mode, reaction cups are placed in the clamping frames, a surrounding plate is coaxially installed on the outer side of the reaction disc, and an air cylinder is arranged in the detection direction of the surrounding plate; a detection clamping plate is fixedly installed at the telescopic end of the air cylinder, a car frame is rotationally installed on the surrounding plate, the detection clamping plate and the car frame are intermittently clamped, a machine shell is arranged in the center of the reaction disc, a hydraulic cylinder is installed on the machine shell, a driving clamping plate is arranged at the telescopic end of the hydraulic cylinder and corresponds to the detection clamping plate, and a beating plate is rotationally arranged on the machine shell. A beating assembly is further arranged on the machine shell. According to the scheme, different stages can be detected, transferring and clamping of the reaction cup are automatically achieved, detection and automatic discharging are carried out in the stable state, and detection is more automatic.

The application is a grading combination variable diameter beaker rack for heating glassware in a water bath, which belongs to the grading combination variable diameter beaker rack for protecting glassware from swinging. The rectangular frame of the beaker rack has two lateral partition bars and front and back frame bars. Each partition bar is provided with vertical positioning holes from the upper surface to the lower surface, and the lateral surface of the partition bar is provided with a sliding groove. The frame bar is provided with a frame bar threaded horizontal hole. The lateral surface of the sliding block in the frame is provided with a horizontal hole. A rotating rod is arranged in the frame bar threaded horizontal hole and the horizontal hole. The spherical end of the rotating rod is connected with a clamping device. The spherical segment shaped universal shell of the clamping device is fixedly connected with the back surface of the slot of the arc-shaped short tube. The flexible rubber strip is embedded in the slot of the arc-shaped short tube. The part of the flexible rubber strip outside the slot is used for flexible contact with the glassware. The problem of damaging the glassware due to the lack of a device for fixing the glassware in the water bath is solved. The problem of clamping and fixing various glassware with large diameter changes in the water bath is also solved.

The present invention discloses a filter element integrity testing device, which belongs to the field of filter element testing. A filter element integrity testing device includes a test water tank and a video microscope fixed on the top of its side wall, and also includes a lifting sleeve, the top of the side wall of the test water tank is fixedly connected to an electric push rod, the lifting sleeve is fixed to the bottom of the telescopic end of the electric push rod, and both sides of the lifting sleeve are slidably connected to a clamping rod; the present invention drives the filter element as a whole to rotate in the liquid through the friction between the driven wheel and the driving wheel, so that the filter element is fully immersed, ensuring the accuracy of the filter element integrity test, and at the same time, with the setting of the push-pull disk, push-pull rod and piston plate, gas can be continuously filled into the filter element. At this time, the low-pressure area on the top of the filter element is detected in real time by using the video microscope, and the bubble distribution on its surface is observed to evaluate the integrity and filtration accuracy of the filter element, thereby improving the test effect.

The present invention belongs to the technical field of biological product purification, and in particular to a biological product purification efficiency detection device, comprising a liquid chromatography detector shell, a solvent box installed on the top surface thereof for holding a solvent bottle, each of the diamond-shaped edge grooves is hinged with an L-shaped solvent clamping rod component with an included angle less than degrees, the bottom ends of the two L-shaped solvent clamping rod components arranged opposite to each other are hinged and slidably connected to each other, and their common bottom surface is connected to a solvent buffer air spring component for shock absorbing the solvent bottle, the solvent buffer air spring component is fixed on the inner bottom wall of an adapter mounting tube, and the top surface of the end portions thereof that are hinged and slidably connected to each other is provided with a bearing and pressing base for bearing the solvent bottle to press downward, the top ends of the two L-shaped solvent clamping rod components are hinged with a solvent stabilizing splint that can drive the L-shaped solvent clamping rod components to flip centripetally and clamp them to the solvent bottle as the bearing and pressing base descends.

A system (10) for the ultrasonic preparation of samples includes an ultrasonic horn (14) having a face (16), a support bracket (22), and a rack (24). The support bracket includes first and second portions (42, 44) moveable with respect to each other, such that movement between the two varies a distance between the rack and the horn face. The first and second portions are securable with respect to each other, such that the distance between the rack and the horn face can be maintained. A spacer (60) having a dimension equal to a target distance between the rack and the horn face is positioned between the rack and horn face such that the first and second portions are moved with respect to each other until the target distance is achieved, the first and second portions are secured with respect to each other, and then the spacer is removed.