Abstract:
An accelerometer comprising a support (52) and a proof mass (40) mounted to the support by a flexure (50) or the like, such that the proof mass can rotate about a hinge axis (HA) perpendicular to sensitive axis (SA). An isolator (42) is also mounted to the support by an isolator suspension system (60, 62) that is relatively compliant for isolator movement parallel to a transducer axis (TA) normal to the hinge axis, and relatively noncompliant for isolator rotation about the hinge axis. Force transducers (80, 82) are connected between the isolator and the proof mass. The force transducers are parallel to the transducer axis, and positioned on opposite sides of the hinge axis from one another, such that rotation of the proof mass about the hinge axis puts one force transducer in tension and the other force transducer in compression. The isolator suspension system reduces the magnitude of common mode inputs, such as those caused by differential thermal expansion of the crystals with respect to other accelerometer components.
Abstract:
A scraper for an optical surface of a device is disclosed. The scraper includes a blade having an edge that is rigid and non-deforming to withstand high shear stresses. The blade is configured to rotate about a first axis parallel to the optical surface and also configured to move in a line with respect to a second axis perpendicular to the optical surface. This allows the rigid, non-deforming blade to maintain contact with the optical surface. Furthermore, the edge is configured to move across the optical surface to remove any materials adhered to the surface. The scraper can be used to clean the optical surface of an instrument, for example.
Abstract:
A prosthetic ankle joint includes a first joint structure having a foot attachment plate connecting a pair of spaced apart parallel fins lying in a sagital plane. A second joint structure having a pylon attachment plate is connected to a support block positioned between the fins of the first joint structure. The first and second joint structures are connected to each other by a spherical bearing that allows the joint structures to pivot with respect to each other about three orthogonal axes. The spherical bearing is connected to the first joint structure through an axle that extends through an aperture in the bearing. A rod extending from the bearing is threaded into a bore formed in the support block of the second joint structure. Dorsiflexion and plantar flexion cushions are positioned between the support block and respective surfaces of the first joint structure to resist pivotal dorsiflexal and plantar flexal pivotal movement of the ankle joint. Lateral cushions are positioned on opposite surfaces of the support block between the support block and respective fins to resist coronal and transverse pivotal movements of the ankle joint.
Abstract:
A preloaded stabilizer mechanism in a dot matrix line printer having a reciprocating carriage is provided to: (1) establish a rigid reference point that prevents the print line of the dot matrix line printer from drifting; (2) eliminate backlash; and, (3) create a carriage resonance frequency that is greater than the carriage operating frequency to enhance printer system stability and the reduction of vibration. The stabilizer mechanism is mounted on a support frame of the dot matrix line printer and includes a modified c-shaped bracket member and a spring plate. The spring plate is attached to one end of the bracket member to form a slot. The slot of the stabilizer mechanism receives an offset shaft that is coupled to a shuttle mechanism that provides the carriage with reciprocating motion. The spring plate of the stabilizer mechanism, being slightly deflected, imposes a force against the offset shaft. As the carriage is reciprocated back and forth along its line of movement, the offset shaft moves back and forth along a line that lies parallel to the carriage movement line. When the shuttle mechanism is out of balance with the carriage, the offset shaft imposes a force, corresponding to the amount of the imbalance, against the preloaded spring plate and bracket opening. In this state, the stabilizer mechanism, due to the offset shaft/slot arrangement, works in conjunction with the shuttle mechanism to translate the shuttle. The stabilizer mechanism inhibits the movement of the offset shaft with respect to the printer support frame when the force created by the imbalance is equal to or less than the force of the preload generated by the spring plate.
Abstract:
A drive system for providing different excitation voltages to the separate beams of a multiple beam vibrating transducer is disclosed. In one embodiment of the invention an amplified voltage at the resonant frequency of a master beam is amplified and applied to a secondary beam, to force the secondary beam to vibrate at the resonant frequency and amplitude of the master beam to force the transducer to resonate at the frequency of the master beam. Since the transducer vibrates at the resonant frequency of one of the beams, the transducer energy losses to the adjacent mounting structure are reduced. This results in a higher transducer quality factor so that frequency shifts in the resonant frequency can be readily measured as changes in the parameter that the transducer is intended to monitor.
Abstract:
A matched pair of vibrating beam force transducers for use in an instrument such as an accelerometer, to provide enhanced linearity and common mode tracking, while decreasing the possibility of lock in or cross-talk between the transducers. In a preferred embodiment, first and second transducers are provided, the transducers producing respective first and second output signals having respective first and second frequencies. The transducers are connected in an arrangement in which for a given acceleration, one frequency increases and the other frequency decreases. The first transducer comprises a pair of first beams, and the second transducer comprises a pair of second beams. The beam dimensions are selected such that the Euler buckling constants of the first and second transducers are substantially equal to one another, and such that the first and second frequencies are different from one another when the acceleration is zero and preferably are different from one another throughout the operating range of the accelerometer. In preferred arrangements, the transducer beams have a constant thickness, and the transducers have common axial stiffnesses.
Abstract:
A scraper for an optical surface of a device is disclosed. The scraper includes a blade having an edge that is rigid and non-deforming to withstand high shear stresses. The blade is configured to rotate about a first axis parallel to the optical surface and also configured to move in a line with respect to a second axis perpendicular to the optical surface. This allows the rigid, non-deforming blade to maintain contact with the optical surface. Furthermore, the edge is configured to move across the optical surface to remove any materials adhered to the surface. The scraper can be used to clean the optical surface of an instrument, for example.
Abstract:
A printer (24) for printing upon a continuous web of print receivable media (18) is provided. The printer includes a print head (28) having a media drive assembly side and a media drive assembly for moving the media across the print head. The media drive assembly is disposed only on the media drive assembly side of the print head. The printer further includes a platen (30) disposed adjacent the print head and a controller (102) coupled to the print head, the media drive assembly, and the platen. The controller controls the printer during continuous printing and single sheet printing. During continuous printing, the media is moved in a downstream direction past the print head. During single sheet printing, the media is moved past the print head in an upstream direction one sheet at a time. Further, the printer may perform single sheet pull printing or single sheet push printing.
Abstract:
A shutter for use in an electro-optical scanning device having an aperture and a CCD imager is provided. The shutter comprises a light barrier movable between a first position blocking light from passing through the aperture and a second position enabling light to pass through the aperture. The light barrier has a magnetic portion. An inductive coil is disposed relative to the magnetic portion of the light barrier to cause movement of the light barrier between the first and second positions by application of an electric current to the inductive coil. The inductive coil is disposed concentrically around the aperture, and the light barrier comprises a magnet that is coupled to a torsional wire disposed within the inductive coil. The torsional wire has a bias that returns the light barrier from the second position to the first position. Alternatively, the light barrier is moveable either pivotally, rotationally, or axially relative to the aperture, and further comprises a corresponding iris. The corresponding iris aligns with the aperture upon the light barrier being pivoted, rotated or axially moved to the second position.
Abstract:
An apparatus and method is presented wherein the lens system or assembly is fixed in its location along an optical axis between an object and its image. The focusing of the object, which may vary its position along the optical axis, occurs through adjusting a detection medium or an imager to the position in image space where the image space is focused on its image plane. The invention is structured to facilitate this focusing in an automatic and very rapid manner to accommodate rapid changes in the location of the object along the optical axis.