Abstract: The problem of providing a simplified actuator apparatus (10) for converting unidirectional motion to multidirectional motion is provided by a driven member (14) rotatable about a first axis (18) and a drive member (12) rotatable about a second axis (28) generally parallel to and spaced from the first axis (18). The driven member (14) has first (20) and second (22) radially disposed, diametrically opposed cam followers. The drive member (12) has first (36) and second (38) radially disposed cam actuators. The first cam follower (20) of the driven member (14) is engageable by the first cam actuator (36) of the drive member (12) for driving the driven member in one direction of rotation in response to rotation of the drive member in one direction.

Abstract: A control device for a tiltable mounting head, such as the mounting head for a camera, has a three element pantographic linkage including a rigid control arm of which an intermediate point is constrained to move along a horizontal path. One end of the arm is pivotally mounted to an arm carrying the tiltable head, while the other end is pivotally mounted to a locating arm whose remote end is pivoted to fixed structure. The relative angular position of the two arms is controlled by two parallelogram linkages with different degrees of fold and having the central arm in common, whereby one of the two linkages is always laterally spaced from the arm. Alternatively the two arms may be secured to respective sprockets pivoted to the arm and connected together by a chain.

Abstract: An apparatus for writing servo tracks on a magnetic disk in a head disk assembly having a head, a moveable actuator for positioning the head relative to the disk, and an actuator drive for moving the actuator to position the head at selected radial positions relative to the disk for writing the servo tracks at those positions, the apparatus including a support for supporting the head disk assembly in the apparatus in a writing position to have the tracks written, a biased tracking element mounted to be biased against the actuator when the head disk assembly is in its writing position, thereby to track the movement of the actuator and the head to the selected radial positions, and a feedback circuit connected between the tracking element and the actuator drive for monitoring the position of said tracking element as a measure of the radial position of the head for controlling the action of the drive to move the head to the selected radial positions within a desired degree of radial accuracy.

Abstract: A gear box (30) housing a reduction gear unit (24) and supporting a drive motor (22), and a elongated screw shaft (12) is fitted over a base plate (14) so that an area of a shaft supporter (10) projected in a plane perpendicular to a longitudinal direction of the elongated screw shaft is reduced, which supporter supports both ends of the elongaged screw shaft (12) for moving a movable element such as an arm of an industrial robot in a predetermined direction. Furthermore, a circular boss portion (32b) provided at the lower face of the gear box (30) and a hole (14a) provided at the base plate (14) are used for positioning the gear box on the base plate (14), and the positioning in a height direction is achieved by positioning elements (40) having a predetermined height dimension when the gear box (30) is attached to the base plate (14).

Abstract: The apparatus for the moving of articles, vessels or of liquid, pasty and/or pourable media has an articulated system with at least six links (1 to 6), each of which is connected to two neighboring links (1 to 6) in each case so as to swivel about axes of articulation (A12 to A61) to form a closed articulated chain. The swivel axes (A12 to A61) of each element (1 to 6) form fixed angles of articulation (W1 to W6). At least one link (2) is connected to an article, the vessel or a means of moving the media.

Abstract: In an image forming apparatus, a mechanism is provided between an upper frame and a lower frame, rotatably connected to each other so that the upper frame can be opened for separating a developing unit in the upper frame, closely united with an image forming drum in the upper frame when the developing unit operates, from the image forming drum so as to have a gap as wide as that the developing unit and/or a drum unit including the image forming drum can be mounted or demounted without damaging a cylindrical surface of the image forming drum, when the upper frame is opened for exchanging the drum unit and/or the developing unit.

Abstract: A switch assembly having an actuator including a body with at least one movable section, a rocker switch having at least one movable cap which is movable to one switch position of at least two switch positions of the rocker switch, an activating assembly having a housing containing at least one movable part contacting the movable cap of the rocker switch and a cable for operationally connecting the movable section of the actuator to the movable cap of the rocker switch. The first end of the cable has an outer sheath removably attached to the body and an inner connector connected to a first end of the movable section. A second end of the cable has the outer sheath removably attached to the housing and has the inner connector connected to a first end of the movable part. When the movable section is moved, the movable cap is changed from one switch position to another switch position via the cable and activating assembly.

Abstract: The invention regards a flap linkage for several rotary flaps arranged along a parallel axis and positioned within a frame. The rotary flap shafts have a double-armed lever on each end. Transmission elements of an adjustment gear mesh on the arms of the double-armed lever. The transmission elements are rigid pushrods, and the levers have been configured in an articulated manner on the ends of the rotary flap shafts. The swivel axes of the levers are parallel to a line that intersects the rotation axes of the pushrods at the lever arms. Hubs have been rigidly connected to the ends of the rotary flap shafts. The hubs are supported with the aid of springs against the intermediate levers mounted on the ends of the rotary flap shafts.

Abstract: The invention relates to a device for changing the position of a functional element in an electrical apparatus. The particular the head-mounting plate in a magnetic-tape apparatus, the functional element being mechanically movable between a rest position towards which it is spring loaded, and two spaced-apart operating positions, i.e. a first operating position and a second operating position. The functional element is electromagnetically held in the first operating position by an electromagnetic device and, when it leaves said first position owing to the electromagnet device being de-energized, can be held in the second operating position with the aid of the mechanical holding function provided by a mechanical holding device.

Abstract: A light weight, foldable, luggage carrier capable of being folded to a flat package storable beneath the seat of an airplane or a train. The carrier having larger than normal diameter wheels whose axis rotates inwardly between the frame members when the luggage support frame is raised to the closed or stored position. This conversion of the carrier from the open to the closed position can be accomplished by the use of one hand.

Abstract: The invention relates to a device for charging the position of a functional element in an electrical apparatus, in particular the head-mounting plate in a magnetic tape apparatus. The functional element being movable between a rest or stand-by position and two spaced-apart operating positions, i.e. a first and a second operating position. The functional element, which is spring-loaded towards its rest position, is held electromagnetically in the first operating position. In order to cooperate with a first electromagnet device in both operating positions, the functional element is provided with a first armature plate. A control device controlled by a second electromagnet device, sets the non-extended functional element to its first operating position after said element has been applied to the first electromagnet device and extends the functional element, while applied to the first electromagnet device, to set it to its second operating position.

Abstract: Disclosed herein is a control for a hydrostatic transmission having an operating member rotatable about a fixed pivot axis between a range of forward drive positions, a neutral position, and a range of reverse drive positions, which control comprises an actuating member adapted to be fixed to the operating member for common movement therewith about the pivot axis and having a portion adapted to be connected to an actuating link to effect pivotal movement of the actuating member about the pivot axis, first and second return members mounted on the actuating member in facing relation to each other and for independent pivotal movement about the pivot axis, a pin fixed on the actuating member and extending between the first and second return members, a spring urging the return members toward each other and into engagement with the pin, a neutral adjustment member, and structure located in fixed relation to the pivot axis for locating the neutral adjustment member between the first and second return members and for

Abstract: An actuator swing arm mechanism includes extension shafts which are rigidly and coaxially attached to the drive shaft of an actuator at one end and rigidly attached to a swing arm at the other end. These extension shafts, rather than the drive shaft of the actuator itself, are rotatably supported by supporting members such that the weight of a heavy load on the swing arm is communicated through these extension shafts to and carried by these supporting members and the drive shaft of the actuator is relatively unaffected by the load.

Abstract: An improved characterizing linkage assembly of the type utilized to proportion the flow of fluids in response to motor controls, such as in the control of fuel and air mixtures in industrial combustion systems. The linkage system comprises a cam assembly having an adjustable curvilinear cam band, which is rotatable by a drive shaft. A biased follower rod, bearingly supported for reciprocal movement, is urged against the cam band. Movement of the follower rod pivots a linkage actuator arm which is bearingly supported on the drive shaft. Rotation of the drive shaft in response to a change in a selected process parameter imparts movement to the cam band, the follower rod and thus the linkage actuator arm being the proportional travel.

Abstract: Actuator for locking device of doors and trunks of automobiles comprising a rotating member that is rotated by a power source; a cam groove formed in the rotating member; a cam follower that moves along the cam groove;anda displacement member which moves between a first position and a second position as a result of the movement of the cam follower. If the cam follower should stop in a communicating groove, the disk can be rotated by a small motor or the cam follower can be operated normally under circumstances when the motor fails.

Abstract: A shift assisting mechanism for a marine transmission including a pair of wire actuators that are connected by means of a pair of levers which are, in turn, connected by a motion transmitting mechanism that provides a lost motion so that excess movement of one of the wire transmitters will not place bending forces on the other of the levers.

Abstract: A linkage device connectable between adjacent ends of a tubular support member and payload member is adapted to rotate the payload member through approximately 180.degree. about the end of the support member between inoperative and operative positions by movement of an actuating rod longitudinally within the tubular member. The linkage device comprises first and second frames secured to adjacent ends of the members and four bars pivotally connected at opposite ends to corners of the frames, the first pair of bars extending within the frames and the second pair extending outside the frames. The actuating rod is connected to the first pair of bars and rotates them about their pivotal connection to the first frame when the rod is moved longitudinally within the tubular member. Both pairs of bars cause the payload member to rotate about the end of the support member through 180.degree. and into an operative position in longitudinal alignment with the support member.

Abstract: Device for transforming a rotary movement of a drive element eccentrically arranged about a rotary spindle into a linear movement of a slide means with an assured guidance during the linear movement and fixed end positions, whereby for the linear guidance of the slide means the drive element constructed as a guide pulley or the like engages in a guide slot, but leaves the latter on reaching the slide means end position, characterized in that on the slide means (3) are provided two rollers (14,15) or similar stops, which in the end positions of slide means (3) in each case slide onto and engage on a bar (32,33) or similar reference edge, the bars (32,33) freeing the rollers (14,15) during the linear guidance of slide means (3) and while maintaining a spacing (b).

Abstract: The motor saw has a rear handle connected to the body by vibration-damping elements with rubber or steel springs, and the throttle of the carburetor and the throttle control are connected by a rigid wire link. The throttle control bearing includes a shaft mounted in oblong holes to give a longitudinal play so that when the handle is moved with respect to the body, the throttle control can move the corresponding distance in the bearing without influencing the setting of the throttle in the carburetor in its idle position. When the handle is moved in this position, and a throttle opening is desired by moving the throttle control, a sliding part at the rear end of the throttle will contact a curved partition in the handle and push the throttle control to an advanced position, after which an opening of the throttle takes place by further movement of the throttle control.

Abstract: Apparatus for moving a pivotable gate or the panel of a swinging door has a U-shaped or H-shaped frame with a plate-like web which supports a motor and two flanges which carry a turnable output shaft receiving motion from the motor by way of a linkage. The motor serves to turn the output shaft to one end position and one or more springs are used to permanently bias the output shaft to another end position. The web has holes for screws which are used to secure the frame to a housing or a like support, e.g., in a recess so that the web overlies the open side of the recess and the output shaft is located externally of the housing to be connectable to or detachable from a gate or a door panel. The frame and the parts thereon can be assembled at the manufacturing plant into a self-sustaining module.

Abstract: A device for the exchange of specimens, for example for X-ray analysis, comprises a bush which is secured to a piston accommodated in a cylinder so that displacement of a pressurized fluid in the cylinder displaces the piston and the bush parallel to a center line of the bush. When structure for restricting the displacement are provided, the specimens can be exchanged between two positions to be selected.

Abstract: Industrial vehicles incorporating obstacle detection systems are commonly employed in commercial applications. Advantageously, such collision avoidance systems should incorporate failure detection systems sufficient to make such systems fail-safe. The subject obstacle detection system includes one or more transducers 24,24' adapted to produce article detected signals in response to sensing an obstacle in front of the vehicle 12. Preferably the transducers 24,24' are pivotally mounted to the vehicle 12. The transducers 24,24' are adapted to produce the article detected signals at regular predetermined intervals, and a sensor failed signal is produced in response to the transducers 24,24' ceasing to produce the article detected signal at such regular intervals.

Abstract: A coin-operated telephone having a housing enclosing a coin acceptor and an associated coin release mechanism which are positioned above a display area. A coin release actuator mechanism is mounted on top of the coin acceptor and includes a rocker arm which is pivoted downwardly by a coin release bar assembly which is secured to and extends across the interior of the housing and is pivoted downwardly by the coin release lever on the front of the housing. The assembly is located above the display area and provides ample clearance in the housing to later add "smart" features while also providing a large display area.

Abstract: A coin-operated telephone having a housing enclosing a coin acceptor having a coin release mechanism secured thereto. A coin release mechanism actuator assembly is carried in the housing and disposed for actuation of the coin release mechanism by causing upward pivotal movement thereof. The coin release mechanism includes a downwardly depending member which is engaged by a roller of the actuator assembly which is comprised of two pivotal L-shaped members connected by a link or rod for transmitting pivotal movement from a first of the pivoted members to a second of the pivoted members. Stops are provided to limit the movement of the members to prevent binding thereof.

Abstract: A hand operable rope locking device which avoids sliding metal to metal contact of the wearing parts and uses a roller engageable in over center relation with a replaceable elastomeric insert in a pivotally mounted metal locking dog.

Abstract: Switch, forming part of a mail sorting device and comprising, according to the invention, one or two rotatable or translatable switch vanes (7), which are driven, by way of one or more curve followers (6, 22) and one or more curve discs (8, 23), by one electromechanical converter, e.g. a tachometrically controlled direct-current servomotor (12). In this case the transmission ratios have been chosen in such a way that the external (virtual) mass moment of inertia is about equal to the internal mass moment of inertia of the motor. The invention can also be utilized for other quickly intermittent drives.

Abstract: An improved characterizing linkage assembly of the type utilized to proportion the flow of fluids in response to motor controls, such as in the control of fuel and air mixtures in industrial combustion systems. The linkage system comprises a cam assembly having an adjustable curvilinear cam band, which is rotatable by a drive shaft. A biased follower rod is urged against the cam band, and upon movement thereby, pivots a linkage actuator arm which is bearingly supported on the drive shaft. Rotation of the drive shaft in response to a change in a selected process parameter imparts movement to the cam band, the follower rod and thus the linkage actuator arm in proportional travel.

Abstract: An angle adjustment mechanism for a fishline guide roller of a spinning wheel having a bail lever wherein the guide roller is rotatable along a first arc and may be set into selected positions along the first arc by rotation of an eccentric cam to select a particular angular position of the guide roller in the bail lever to compensate for the amount of fishline wound on the reel and the type of fishline used. The cam includes a slot for receiving stop projections arranged along a second arc around the cam to maintain the guide roller in a selected angular position in the first arc.

Abstract: A device is provided for mechanically coupling two parallel shafts together allowing rotation thereof in a 2/1 ratio in an angular sector defined, by producing a very rigid connection without lost motion, with a minimum of parasite torque and insensitive to environmental vibrations. It includes a first piece mounted on a shaft and having two guide elements and a second piece mounted on a shaft having two arms provided with flat surfaces on which the guide elements move. The center of these latter, as well as the axis of rotation of the second shaft, are on a circle centered on the axis of rotation of the first shaft. Preferably, one of the pieces is made in two parts, one being integral with the associated shaft and the other freely mounted on this shaft, and a return spring holds said guide elements against the flat surfaces, these elements being formed by ball bearings.

Abstract: A foldable baby carriage is provided which is foldable to a compact, reduced volume configuration having a height and width essentially less than or equal to the height and width of the back member. In the folded configuration, two of the components, preferably the back member and rear wheels support, cooperate to form a shell which encloses the other two major components of the carriage, preferably the seat member and the front wheels support.

Abstract: A door actuating mechanism is provided for opening and closing of door structures over recessed headlights in a vehicle. The actuating mechanism includes means to cause pivoting of the doors to the open or closed positions and simultaneous sliding of the doors sideways with respect to the opening for the recessed headlights to prevent engagement of the doors with the side edges of the opening during opening and closing of the door.

Abstract: Detection systems for identifying an object in the path of a vehicle are affected by external interferences which render them unreliable. An oscillating scanner arrangement having first and second spaced apart transceiver assemblies is mounted on a frame of the work vehicle at spaced apart locations and are each pivotally movable between spaced apart angular positions. First and second devices pivotally connect the first and second transceiver assemblies respectively to the frame, and a power device reciprocally moves the first transceiver assembly between the first and second positions. A tie arrangement connects the first transceiver assembly to the second transceiver assembly and reciprocally moves the second transceiver assembly between the third and fourth positions. Thus, the problems related to external interference are solved in an efficient and economical manner. The oscillating scanner arrangement is particularly suited for use on a material handling vehicle.

Abstract: A direct drive robot which includes a pedestal having two motors which rotate around a common axis to directly drive rotation of first and of second linking arms which are rotating in a plane perpendicular to this pedestal. The first, inner link is preferably driven through a column directly driven by a first motor rotor, the column supporting the inner end of the link. The second, outer link is driven by the second coaxial direct drive motor through a simple, highly-tensioned belt and pulley arrangement. As a result of this direct drive arrangement, movement is provided about two separate parallel axes by two arms arranged perpendicular to the first axis which mounts the two major driving motors of the robot. These two arms are linked together between this major pedestal and the end effector of the robot, centralizing the driving motors at the main stabilizing pedestal, while providing rapid rotational movement around each of the two axes.

Abstract: An apparatus for controlling a vehicle air conditioner having a speed setting mechanism interconnected to the output shaft of an actuator for turning an air mixing shutter so as to switch the blower between low and high speed operations. The cam mechanism has the first rotary part interlocked to the output shaft of the actuator and a response part in response to the rotary part to turn the air mixing shutter. When the output shaft is turned within a predetermined rotary range c set narrower that the entire rotary range of the output shaft, the air mixing shutter can be turned between full cooler and heater positions. The speed setting mechanism brings the blower to a low speed operation when the rotary angle of the output shaft falls within the rotary range c and to a high speed operation when the rotary angle of the output shaft falls outside the rotary range c.

Abstract: A toy is constructed to include two unique linkages with the first linkage including a series of links located in a sequential array with each link pivotally connected to its next immediate adjacent neighbor and every other link operatively connected such that each link can pivot with respect to its neighbor and motion of a link pivotally connected to one side of a link is communicated to the link pivotally connected to the other side of that same link. This allows the linkage to propagate motion along the totality of the sequence in response to movement of any one link. The second linkage includes a first member which is pivotally connected to a rotating crank pin and connected at its upper end to a second lever which is pivotally connected to a body on which the crank pin rotates.

Abstract: A motion transmitting apparatus converts the uniform rate of motion of a piston and cylinder actuator to a programmed motion having a controlled acceleration, a dwell and a controlled deceleration.

Abstract: A locking mechanism comprising: a frame; a first rotational member being supported on the frame so as to rotate around a first axis and having a guiding portion having a component extending in the radial direction with respect to the first axis; a second rotational member being supported on the frame so as to rotate around a second axis parallel to the first axis and having an engaging portion to be slidably guided along the guiding portion at the position apart in the radial direction with respect to the second axis, wherein the guiding portion has a stopper capable of being in contact with the engaging portion at the position most apart from the first axis, and when the engaging portion is in contact with the stopper, an angle which a straight line tangential to the guide way of the guiding portion forms with a straight line connecting the engaging portion with the second axis is substantially 90.degree..

Abstract: A low-temperature showcase in which a double air curtain can be formed for commodity inlet-outlet opening provided in one side of its main body comprising: a heat exchanger in an inner passage being positioned upstream of and at a predetermined distance from another heat exchanger in an outer passage with respect to the same direction of air flows, a partition wall defining the inner and outer passages and having a first window at a portion thereof between the two heat exchangers, a closure plate for opening or closing the first window to close or open the inner passage downstream of the first window, and first control unit for giving instructions to the closure plate for its operation, the first control unit being operative to instruct the closure plate to open the first window and close the inner passage downstream of the first window when the heat exchanger in the inner passage is operated for defrosting with the heat exchanger in the outer passage operated for refrigeration, whereby the air flow through t

Abstract: A fuel control valve construction, parts therefor and methods of making the same are provided, the construction having a housing provided with an inlet adapted to be interconnected to a fuel source and an outlet adapted to be interconnected to a burner. The housing has a main pressure regulator and a main valve operated by the main pressure regulator for controlling fuel flow from the inlet to the outlet to provide a full rated flow of fuel to the burner. The housing has a by-pass for interconnecting the inlet to the outlet to provide a fuel flow to the burner that is less than a full rated flow of fuel but is sufficient by itself to support combustion at the burner until the main valve provides the full rated flow of fuel thereto. The housing has a by-pass pressure regulator for controlling the flow of fuel through the by-pass independently of the operation of the main pressure regulator.

Abstract: A sliding-link mechanism is proposed, which serves in particular to actuate a throttle device in the intake tube of an internal combustion engine. The sliding-link mechanism is disposed by way of example on a throttle valve assembly and includes a variable-fulcrum lever, which is firmly connected to a shaft and has a kidney-shaped oblong slot groove, which is engaged by a roller rotatably supported on a shaft. The shaft is secured on a roller lever, which with a hub is seated on an eccentric sleeve, which can be rotatable about a shaft secured to the throttle valve assembly. The eccentric sleeve and the hub have meshing teeth which by axial displacement relative to one another become disengaged, so that by rotating the eccentric sleeve the position of the roller lever relative to the variable-fulcrum lever can be varied in such a way that in the outset position the roller comes to rest on the end of the oblong slot groove.

Abstract: An object mounting member is slideably interconnected with a guide member which provides a path between two separated fixed locations. The guide member is attached to a support member having fixed stops located between the two fixed locations. A pinion gear is fixedly attached to the shaft of a stepper motor, and a spur gear is held in an engaging relationship with said pinion gear. An eccentric arm is pivotally attached at one end to the spur gear and is driven to provide rapid motion between the two fixed locations with a rate of motion approaching zero hit nears each fixed location. The other end of the eccentric arm is pivotally attached to one end of a drive arm that is pivotally attached to the object mounting member. The drive arm includes a spring loaded member that is used to allow the object mounting member to be preloaded against a stop at each end of its travel.

Abstract: A shutter mechanism which includes simultaneous translation of a shutter in two planes of motion prolongs the life of the sealing material of the shutter as well as ensures that, when open, an optical beam passes through a sample compartment without interference or disruption. A further advantage of such a mechanism lies in the positive sealing of a port with sufficient pressure applied via the shutter plate to prevent vapor or fluid communication across the port.

Abstract: The invention relates to a mechanism for selectively converting a continuous rotary movement in apparatus such as a high-speed-printing machine to a phase-related single pivoting movement of a control lever, with that single control movement following by an immediate reset to the initial position regardless of the time of activation of the mechanism. An entrainment lever supported on a supporting pin is coupled by means such as an excentric drive to the continuous rotary movement of the machine to generate a continuous pitching movement. A control lever is mounted for rotation on the same support pin and mounts a bistable mechanism (tensioning lever, pawl 3, tensioning spring 21) which in its first stable condition allows the entrainment lever to oscillate freely and which can assume its second stable condition when entrainment lever is in a dead center position, causing an engagement surface to be offered to the entrainment lever with the range of its pivoting movement.

Abstract: An active ridge vent designed for providing varying degrees of ventilation at the ridge of a building such as a livestock building. An arm in combination with a triangular member, a linkage, and a channel allow the opening created by two opposed doors which are hinged to the open peak of a gable roof to vary. The opening is designed to vary in accordance with the temperature level in the livestock building.

Abstract: A remote control operator for a fluid flow restrictor valve having a flow passageway opened and closed by an angularly rotatable disc moving ports into and out of alignment with companion ports. The valve operator comprises tangentially disposed part-circular plates with one plate secured to the restrictor valve rotatable disc and the other plate angularly rotated by a reversible drive motor. A flexible strand, secured at its ends to diametrically opposite portions of one plate, is tautly entrained intermediate its ends around portions of both plates in cooperating grooves formed in the arcuate peripheries thereof. Energizing the motor in respective directions angularly rotates the plates for opening and closing the valve flow passageway.

Abstract: A rocking rotational angle altering system is equipped with an improved output rotational angle indicating device. The device includes a movable block and a cam rod brought into engagement with each other in rolling contact. The movable block has rolling elements mounted to act as a unit therewith and the cam rod is formed with a flat cam surface engageable with the rolling elements of the movable block.

Abstract: A four bar linkage is movable from a first position to a second position by a continuous motion of a linear actuator. The linkage comprises a first leg and a second leg shorter than the first leg spaced from and parallel to the first leg in the first position. The first and second legs are supported at their lower end by being pivotally attached to a base, and the upper ends of the first and second legs pivotally support an upper platen at their upper end. The first and second legs, the base, and the upper platen comprise the elements of a four bar linkage. The linkage is translated from a first position where the first and second legs are parallel and extend vertically upward to a second position wherein the platen is rotated up to 90.degree. or more and is displaced laterally from the base and can face to the side and upward allowing access to the base and the upper platen from overhead.

Abstract: A compound parallelogram four-bar linkage is provided wherein a first primary link is connected to a second primary link through connector links of substantially the same length and the pivotal angles of the first primary link and second primary link are maintained at substantially ninety degrees as movement is transferred from one primary link to the other so that the resonant frequency of the linkage does not vary and the linkage stiffness is independent of the angle of rotation.

Abstract: A linear actuator for rotating a load, such as an antenna, in which the load is pivoted about a load pivot axis and a drive point on an arm extending from the load is driven along a path of travel defined by a frame pivoted about a frame pivot axis parallel to the load pivot axis and normal to the path of travel, the load pivot axis being equally distant from the drive point and the frame pivot axis. The structure of the linear actuator reduces loss of moment arm at the extremes of travel and minimizes stress on the components of the actuator.