Abstract: A guiding rail includes a guiding profile, a base face, a first end face, a second end face, and a groove. The guiding rail is configured to be placed against a substructure via the base face. The groove is introduced in the base face, and a line for cooling or heating the guiding rail is inserted into the groove.

Abstract: The disclosure relates to a machine tool. The machine tool includes machine base, guide rails, and movable main structure. The movable main structure is slidably disposed on the machine base via the guide rails, and each guide rail has bearing surfaces. The machine tool has X-axis, Y-axis, and Z-axis, the Z-axis is substantially parallel to an axis of a chuck of the machine tool, and the Y-axis is substantially parallel to a sliding direction of the movable main structure. The machine tool characterized in that: normal directions of the bearing surfaces of the guide rails are not parallel to the X-axis, the Y-axis, the Z-axis of the machine tool and a reference line that passes through the guide rails.

Abstract: An apparatus for attaching a transition duct to a turbine section of a gas turbine engine includes an annular shaped vane carrier that engages with a transition aft frame. The transition aft frame includes an outwardly extending clamp that is at least partially inserted into a radial recess of the vane carrier structure. A spacer is inserted into the recess. A first pair of mating surfaces is formed by a first end face of the spacer and an end face of the clamp and a second pair of mating surfaces is formed by a second end face of the spacer and a wall of the recess. At least one of the pairs of mating surfaces is inclined at an angle with respect to a radial plane of the vane carrier structure. A retention device secures the spacer to the vane carrier structure.

Abstract: Provided are X-Y constraining units having excellent yawing attitude precision as well as a stage apparatus and a vacuum stage apparatus, each including the X-Y constraining units. The X-Y constraining units 8 and 9 includes: Y-axis bases 81 and 91 respectively connected to Y-axis sliders 4 and 5 and having a through hole extending along Z direction; X-axis bases 82 and 92 respectively connected to an X-axis guide rail 6; shafts 83 and 93 respectively inserted into the through hole and fixed to the X-axis bases 82 and 92; and a plurality of bearing balls which are located between an inner peripheral surface of each of the through hole and an outer peripheral surface of the shafts 83 and 93, and are arranged so as to circumferentially surround the shafts 83 and 93. Each of the stage apparatus 1 and the vacuum stage apparatus includes the X-Y constraining units.

Abstract: A movement unit for a machine tool comprises a supporting structure movable in a first direction for supporting a functional unit of the machine tool, with two longitudinal guides extending in the first direction which are offset relative to one another in a transverse second direction. A guide unit is mounted on each longitudinal guide to be relatively movable in the first direction and not the second direction. A bearing structure connects the supporting structure to one of the guide units to be not relatively movable in the first direction and movable in the second direction. The bearing structure comprises a bearing receptacle having a receptacle wall extending in the second direction, and a bearing projection which engages the bearing receptacle. The bearing projection and the receptacle wall are supported against one another to prevent their relative motion in the first direction and are movable in the second direction.

Abstract: A guiding system for machine tools of the type having first machine parts with guiding rails fastened thereto and second machine parts supported by shoes on the guiding rails of the first machine parts in such a way that they can be moved with respect to each other. At least in sections along their length that are exposed to high thermal loading, the guiding rails are kept in close pressure contact over a large surface area by cooling bars to which a coolant is applied.

Abstract: A bearing race arrangement on a composite structure having a first coefficient of thermal expansion includes a recess formed in a surface of the composite structure for receiving a race element, at least one bearing race element disposed in the recess, the bearing race element having a coefficient of thermal expansion different from the coefficient of thermal expansion of the composite structure and a retainer securing the bearing race element to composite structure, within the recess and allowing for longitudinal expansion of the race element without creating stress on the composite structure.

Abstract: A linear bearing assembly (the assembly) of the present invention is disposed in a housing of the assembly. A first rail and a second rail are movable relative to one another. A plurality of linear bearings are connected to the housing and disposed about the first and second rails. An actuator device is connected to at least one of the first rail and the second rail to selectively move the first rail and the second rail relative to one another and the housing in at least one of simultaneous and separate modes to redistribute lubricant in the linear bearings thereby preventing deformation of at least one of the first rail and the second rail.

Abstract: A proposed aerostatic bearing arrangement for moving a device on a base structure, particularly in a vacuum environment, has at least one aerostatic bearing element comprising a bearing body having a load-carrying zone and a suction area. An electrostatic preloading unit having at least one electrode is associated with the at least one aerostatic bearing element, and a voltage can be applied to the electrode in such a way that a force component is generated in direction of the surface normal of the bearing body of the aerostatic bearing element.

Abstract: A proposed aerostatic bearing arrangement for moving a device on a base structure, particularly in a vacuum environment, has at least one aerostatic bearing element comprising a bearing body having a load-carrying zone and a suction area. An electrostatic preloading unit having at least one electrode is associated with the at least one aerostatic bearing element, and a voltage can be applied to the electrode in such a way that a force component is generated in direction of the surface normal of the bearing body of the aerostatic bearing element.

Abstract: An exemplary rotation module configured for a gantry apparatus includes a rotary plate, a base, and a bearing. The rotary plate has a through hole. The base is arranged in the through hole. The bearing is arranged between the rotary plate and the base. The bearing includes an inner race and an outer race rotatable relative to the inner race. The inner race is securely coupled to the base and the outer race is securely coupled to the rotary plate, whereby the rotary plate is rotatable relative to the base. A gantry apparatus are also provided.

Abstract: A supporting unit in a moving table device, easily connected to a base and a table, is provided. A supporting unit (U?) has a pair of planar bearing plates. Inside the planar bearing plates are positioned spherical bearing plates, respectively. Further, a spherical axial member is sandwiched between the spherical bearing plates (34a, 34b). A planar bearing is formed between each of the planar bearing plates and each of the spherical bearing plates. A spherical bearing is formed between each of the spherical bearing plates and the spherical axial member. Thus, the supporting unit (U?) is provided with a certain degree of movability in five-axis directions. With the high degree of movability, the supporting unit (U?) can be easily connected to a base and a table.

Abstract: Universal aerial and die-mount cams, each having an adapter assembly, a driver, and a slide sandwiched between the adapter assembly and the driver. The adapter assembly has a universal adapter having an arcuate portion that is angularly adjustable within arcuate recesses in opposing side plates of the universal adapter so that bearing surfaces of the universal adapter slidably oppose a first group of bearing surfaces of the slide and a second group of bearing surfaces of the slide slidably oppose bearing surfaces of the driver, the latter bearing surfaces being parallel to or inclined to the horizontal. Three ranges of longitudinal driver inclination angles can be accommodated by using the same slide and universal adapter and one of two pairs of side plates.

Abstract: Machine for machining large parts of the type that comprises a parallel kinematics machining device that moves freely in the X, Y and Z Cartesian axes, characterized in that the said device is mounted on a platform which moves in the Z axis and is in turn mounted on a bridge that slides along corresponding guides in the X and Y axes. The invention put forward affords the significant advantage of combining the high machining precision and speed of the parallel kinematics machine with the fact that the machine can access large work areas owing to the support platform which is mounted on the bridge.

Abstract: A biaxial linear-revolving guide unit is disclosed, which is comprised of a pair of linear motion guide units each composed of a guide rail and a slider fit over the guide rail, and a revolving bearing installed between the linear motion guide units to joint them for revolving movement relative to one another. The revolving bearing is composed of an outer ring, an inner ring and rolling elements. The inner ring is joined directly to the slider of any one linear motion guide unit while the outer ring is joined directly to the other linear motion guide unit. A table system compact in construction is provided, in which more than one the biaxial linear-revolving guide unit is installed between a moving table and a stationary bed.

Abstract: A bearing assembly is disclosed, which comprises at least two slidable fasteners interengaged with at least two bearing pieces such that the slidable fasteners have substantially unrestricted biaxial motion relative to one another. The bearing pieces are comprised of self-closable fastener film comprising a base sheet and a multiplicity of ribs projecting from the base sheet, wherein the flat side of the first bearing piece is attached to the flat side of the second bearing piece such that the ribs of the first bearing piece are not parallel relative to the ribs of the second bearing piece.

Abstract: A self-contained die cushion assembly for use in a stretch-forming process involving heated tooling. A lower plate is mounted below an upper plate that undergoes different thermal expansion than the lower plate. Guidance devices are mounted between the upper and lower plates and include a guide post, a bearing sleeve circumscribing the guide post, and a cylinder circumscribing the bearing sleeve. The guide post is mounted in fixed relation to the upper plate, and the cylinder is mounted in laterally translatable relation to the lower plate to accommodate lateral relative displacement between the upper and lower plates due to different thermal expansion thereof, thereby preventing binding of the guidance devices.

Abstract: This invention is intended to provide a damping device capable of conducting highly precise damping control. To attain this object, this invention is a damping device used in a machine which includes a rotating object and a motor rotating the rotating object, wherein the damping device includes: a vibration damper filled with an electroviscous fluid having a viscosity changing according to a value of a voltage applied to the electroviscous fluid, and rotatably supporting at least a part of the rotating object in the electroviscous fluid; a voltage applicator applying the voltage to the electroviscous fluid in the vibration damper; and a controller controlling an operation of the voltage applicator so that an optimum voltage, at which the viscosity of the electroviscous fluid absorbing a vibration of the rotating object most effectively is obtained, can be applied to the electroviscous fluid in the vibration damper in accordance with a rotating speed of the rotating object.

Abstract: In order to provide a static pressure air bearing having two axes usable in a vacuum environment in which the connection of the supporting air exhaust pipe does not adversely affect the motion of the bearing mechanism, air exhaust pipes are connected only with the fixed part(s) of the lower axis. Air exhaust from the upper axis is conducted through inner air exhaust piping (passages) formed within the fixed parts of the upper and lower axes, so that the exhaust pipes need not be connected with the movable parts.

Abstract: A bridge bearing in which a substructure and a superstructure are displaceably connected to each other by means of a sliding bearing, whereby the displacement occurs in a linear and/or cardanic manner in at least one of the directions X, Y, and Z. The bearing is characterized in that a carriage (7) that is connected to a cover plate (10) is guided in a linear manner in the X and/or Y direction by two interspaced shafts (5, 4), respectively, on which displaceable slide bushings (9, 8) are arranged and/or the cover plate can be guided in a tiltable manner by a pivot bearing (18) in the Z direction. This combination of a linear and pivot bearing enables all alignment errors arising as a result of finishing inaccuracies, foundation subsidence, desired and undesirable slanting to be compensated and regulates the variations in lengths due to temperature and load.

Abstract: An xy stage assembly having an xy stage supported by support shafts and having preload shafts applying a load to the xy stage. The support shafts or the preload shafts can be drive shafts that drive the xy stage in the x direction. The support shafts and the preload shafts are supported by journal/bearing structures that are individually translatable in the z-direction to selectively provide a pitch, roll or z-axis displacement to the xy stage. The support shafts and the preload shafts can be individually translated in the y-direction to provide yaw to the xy stage. Either the support shafts or the preload shafts or both can have wheels that ride in grooves in the xy stage. Alternatively, either the support shafts or the preload shafts or both can have grooves in the circumference of the shafts and the xy stage has rails in which the grooves on the shafts ride. The xy stage may be divided into two section joined by a compressive layer.

Abstract: A stage device includes a table having a reference plane parallel to first and second directions; a driving body movable along the first direction; a moving body movable along the second direction with respect to the driving body; a static pressure bearing provided on the moving body; an exhaust groove provided surrounding the static pressure bearing; and a mechanism for delivering a gas of the static pressure bearing recovered by the exhaust groove between the moving body and the driving body. The adverse affects of piping on the moving body can be reduced and it is possible to position the moving body with high precision.

Abstract: An xy stage assembly having an xy stage supported by support shafts and having preload shafts applying a load to the xy stage. The support shafts or the preload shafts can be drive shafts that drive the xy stage in the x direction. The support shafts and the preload shafts are supported by journal/bearing structures that are individually translatable in the z-direction to selectively provide a pitch, roll or z-axis displacement to the xy stage. The support shafts and the preload shafts can be individually translated in the y-direction to provide yaw to the xy stage. Either the support shafts or the preload shafts or both can have wheels that ride in grooves in the xy stage. Alternatively, either the support shafts or the preload shafts or both can have grooves in the circumference of the shafts and the xy stage has rails in which the grooves on the shafts ride. The xy stage may be divided into two section joined by a compressive layer.

Abstract: In order to provide a static pressure air bearing having two axes usable in a vacuum environment in which the connection of the supporting air exhaust pipe does not adversely affect the motion of the bearing mechanism, air exhaust pipes are connected only with the fixed part(s) of the lower axis. Air exhaust from the upper axis is conducted through inner air exhaust piping (passages) formed within the fixed parts of the upper and lower axes, so that the exhaust pipes need not be connected with the movable parts.

Abstract: A temperature indicator is mounted within a wheel hub to generate a warning signal when a wheel end component overheats. The temperature indicator comprises a thermal battery that is activated only when the wheel end component exceed a predetermined temperature. Once activated the battery powers an RF transmitter to generate a wireless warning signal that is transmitted to a remote receiver to display a warning.

Abstract: An EGR valve having a self-compensating bearing assembly for use with a valve member having a shaft reciprocable within a valve body, includes a rigid bearing member for providing radial support and axial guidance to the valve shaft as the shaft reciprocates in the valve body; and a pliant annulus supporting the bearing member, where the pliant annulus has a density and thickness sufficient to accommodate distortion of the rigid bearing member in response to changes in temperature without interfering with shaft actuation.

Abstract: A high precision friction drive positioning stage system is described. The friction drive positioning stage system uses three special actuation systems, each having a tip in contact with the stage and being capable of generating directional elliptical motion which allows the stage to move in any direction in the plane of the stage and in rotation. In one embodiment, each actuation system includes a plurality of piezoelectric elements in contact with a hat-shaped element at which the tip of the actuation system is located.

Abstract: A two-axis stage assembly includes a generally planar horizontally mounted base plate; a stage plate generally parallel to the base plate, the stage plate having a first axis and second orthogonal axis; a set of spaced bearings depending from a bottom surface of said stage plate, the bearings each having an arcuate bottom surface in rocking contact with a facing support surface of the base plate; a joint attached to the bottom surface of the stage plate and pivotably mounting each bearing, the joint being positioned at the center of curvature of the arcuate bottom surface of the associated bearing; and where an axial movement of the stage plate rocks the bearing arcuate bottom surfaces with respect to the facing support surface of the base plate.

Abstract: A stage apparatus comprises a pedestal, an X axis guide bar which is fixed on the pedestal, an X stage which is movable along an upper surface of the pedestal and the guide bar, and a Y stage which is placed over the X state and movable along the pedestal in a direction of the Y axis. Vacuum-pre-loadable static pressure air bearings, in which pressures of vacuum ports are independently controllable, are provided on a surface of the X stage opposing to the pedestal and on another surface of the X stage opposing to the X axis guide bar. By using the stage apparatus, the electric power consumption of driving means for movable units can be reduced, the amount of heat generation can be reduced, and the bearing gap can be adjusted highly accurately after assembling.

Abstract: A modular manipulation unit is disclosed. The unit includes a body (11) formed of three extruded, profiled elements. The elements include a base plate (15), a top element or cover (16) fixed on the base plate, and an intermediate slide (17) arranged and guided between the base plate and the top element. An interface part (13) is fixed and movable with the intermediate slide, and an actuator is connected to the said intermediate slide for movements of same and of the gripping tool carried by the said interface part.

Abstract: A two-axis stage assembly includes a generally planar horizontally mounted base plate; a stage plate generally parallel to the base plate, the stage plate having a first axis and second orthogonal axis; a set of spaced bearings depending from a bottom surface of said stage plate, the bearings each having an arcuate bottom surface in rocking contact with a facing support surface of the base plate; a joint attached to the bottom surface of the stage plate and pivotably mounting each bearing, the joint being positioned at the center of curvature of the arcuate bottom surface of the associated bearing; and where an axial movement of the stage plate rocks the bearing arcuate bottom surfaces with respect to the facing support surface of the base plate.

Abstract: A stage apparatus comprises a pedestal, an X axis guide bar which is fixed on the pedestal, an X stage which is movable along an upper surface of the pedestal and the guide bar, and a Y stage which is placed over the X stage and movable along the pedestal in a direction of the Y axis. Vacuum-pre-loadable static pressure air bearings, in which pressures of vacuum ports are independently controllable, are provided on a surface of the X stage opposing to the pedestal and on another surface of the X stage opposing to the X axis guide bar. By using the stage apparatus, the electric power consumption of driving means for movable units can be reduced, the amount of heat generation can be reduced, and the bearing gap, can be adjusted highly accurately after assembling.

Abstract: An electrorheological fluid damper for a slide mechanism including a base and a table, is made up of base-side conductive arcuate pipes different in diameter (serving as a positive electrode), and table-side conductive arcuate pipes different in diameter (serving as a negative electrode) which are arranged alternately in such a manner that they are coaxial with one another, so that the contact areas of the electrodes which are in contact with the electrorheological fluid are increased without increase of the size of the damper itself. When the table is being slid, no voltage is applied to the electrorheological fluid, so that the viscosity of the electrorheological fluid is minimum, being of only its solution, and when the table is stopped, voltage is applied to the electrorheological fluid, so that the viscosity of the electrorheological fluid is increased.

Abstract: A rail construction for a machine tool includes a bed made of resin concrete, a pair of laterally spaced rails made of resin concrete which extend along a lengthwise direction of the bed and which and have an upper portion on which a table is slidably mounted, and a reinforcing member inserted into each of the rails such that the reinforcing member is out of concern with the movement of the slide table along the upper surface of each of the rails.

Abstract: A damper assembly includes anti-rattle tracking devices or components for preventing rattling and play when a sliding tray is moved into and out from a stationary housing by a damper device. The damper device further includes a fail-safe locking device so as to maintain the assembly of the locking device for the sliding tray regardless of either a pushing or pulling motion.

Abstract: A machine is disclosed having novel air bearings for supporting one machine part for translational movement on another part in a first direction X. Each bearing takes the form of a track (5A,14,16) on one of the parts providing concave part-cylindrical bearing surfaces (5A,14A,16A) and pads 25 on the other part providing confronting convex part-cylindrical bearing surfaces 25A. The arc lengths of the part-cylindrical bearing surfaces are such as to provide restraint against relative movements between the machine parts in at least one sense of both of the two directions (Y,Z) orthogonal to the direction (X) of the translational movement. The advantages are relative cheapness of manufacture compared to vee-bearings and a capability of the bearings to self-align under load.

Abstract: A bearing for orbital motion includes a first plate having first and second surfaces. The second surface has formed thereon a race and a reservoir which circumscribes the race. A second plate has first and second surfaces. The first surface of the second plate has formed thereon a race and a reservoir which are matingly dimensioned and oriented with respect to the race and reservoir of the first plate. The second surface of the second plate has formed thereon a race, which is oriented perpendicular to the race of the first surface, and a reservoir, which circumscribes the race. A third plate has first and second surfaces, and the first surface has formed thereon a race and a reservoir which are matingly dimensioned and oriented with respect to the race and reservoir of the second surface of the second plate. A first pair of load carrying members are disposed in the mating races of the first and the second plates.

Abstract: A workcenter (10) comprises its supports (14a,b,c) which each carry a carriage (24a,b,c) movable along the supports by motors (30a,b,c) under central computer control (41).Each support is an aluminum extruded U-shaped section having four tracks (28) comprising steel strips (27) in slots (29).The carriage is likewise extruded having undercut slots (83) receiving the heads (92) of axles (90) which have eccentric stubs (96) on which bearing wheels (26) are journalled. Four wheels are so-mounted at each end of the carriage.

Abstract: A ground lead connection is provided to electrically ground a motor armature shaft. In one embodiment the device has a motor housing in which is mounted a bearing. An armature shaft is journaled in the bearing and a ground lead is attached to the bearing. The bearing is provided with a counter bore socket which receives a terminal from the ground lead. The terminal includes a ferrule and a plug which has flared fingers. When connected, the plug engages the bore of the socket and the fingers engage the counter bore to permanently prevent removal of the terminal from the socket. The shaft is thereby grounded via the bearing without the need for numerous parts.

Abstract: A drive apparatus and a XY drive apparatus on which it is equipped that accomplishes highly accurate driving and positioning of a driven object by absorbing deflection of a nut in the radial direction while employing a simple construction.Deflection of a nut is absorbed by deflection of flexible portions as a result of said nut being supported by an intermediate member having said flexible portions able to deflect in a radial direction perpendicular to the shaft center of a feed screw.

Abstract: A combination section consisting of a base section (1) and a covering section (2). The covering section (2) is of an anti-friction material having a coefficient of expansion deviating from that of the material of the base section (1), and is divided between fastening points into partial lengths (4). The partial lengths (4) are interconnected by deformable bridges (6). This makes it possible for the partial lengths (4) to expand essentially unhindered, independent of the expansion of the base section (1) to a different extent.

Abstract: ATE is mounted directly to a support surrounding and removably receiving probe cards of differing thickness. An electrically heated chuck having a variable heat transfer coefficient heat exchanging face confronting a liquid nitrogen supplied plenum exhibits a temperature that varies with electrical heater load, rate of liquid nitrogen supply, and heat transfer coefficient of the heat exchanging face. The rate of liquid nitrogen supply is varied as a function of whether or not the electrical heater load falls outside predetermined upper and lower bounds to establish and maintain set point temperature over a range of set point temperatures including liquid nitrogen temperature and ambient temperature. The chuck is mounted for X,Y movement on load-balanced air/vacuum bearing, and is mounted for Z movement to accommodate different thickness probe cards. A load-lock having a pivoting cassette receiving tray that pivots with a pivoting transfer arm is mounted for Z movement with the chuck.

Abstract: In a movement guiding device, two parallel stationary guides are fixed to a surface plate and plural hydrostatic gas or bearing members are provided for the surface plate and the stationary guides. A Y stage is moved in a Y-axis direction under the influence of these bearing members. Additional hydrostatic gas or air bearing members are provided in relation to the surface plate and the Y stage so as to support an X stage for movement in an X-axis direction orthogonal to the Y-axis direction. Guide of the Y stage in the X-axis direction is made by the stationary guides on the surface plate, while guide thereof in a Z-axis direction perpendicular to an X-Y plane is made by the surface plate. Guide of the X stage in the Y-axis direction is made by the Y stage, while the guide thereof in the Z-axis direction is made by the surface plate, similar to the Y stage. With such structure, any vibration, rolling, or otherwise, of the Y stage is not transmitted to the X stage. Thus, high-precision guide is attainable.

Abstract: A chair for conducting the electrostatic charge of an occupant to the floor on which the chair rests, with the chair seat carried on a support unit which permits rotation of the seat and adjustment of the height of the seat above the floor. The support unit includes an outer sleeve and an inner sleeve moving vertically relative to the outer sleeve, and an electrical resistor connected between the inner and outer sleeves and in sliding contact with at least one of the sleeves, typically by means of a spring finger strip mounted in a groove of a bushing or collar.

Abstract: A gas bearing system for maintaining high static stiffness while damping high and low frequency vibrations. The system includes a bearing shoe having a primary reservoir which is supplied with gas through a primary restrictor, and an auxiliary reservoir. A secondary restrictor couples the primary reservoir to the auxiliary reservoir. Gas passes through ports from the primary reservoir into the gap between the bearing surface of the bearing shoe and a bearing surface of a rail. The secondary restrictor has a resistance to flow of gas therethrough greater than the resistance to flow of gas through the ports but less than the resistance to flow of gas through the primary restrictor. This arrangement provides damping over a larger frequency range than is known in the prior art. Such a system is particularly suitable for use in a gantry-type coordinate measuring machine.

Abstract: Presented is a slide roller apparatus of elegant simplicity, high precision/cost ratio and few parts where the car/track/rollers are relatively movable and the only needed parts (excepting for attachment means). The car is unitary without end caps for the roller groove, the roller groove being machined or otherwise formed into the car with great precision. The ends of the rollers have a sliding engagement with a rail track surface. The tracks and cars may be made of high precision extruded aluminum hard coated and impregnated with a high lubricity material. The rollers preferably are softer than the tracks and may be made of plastic material. The slide roller apparatus has far ranging applications from sail boats to machine tools.

Abstract: A rack and pinion type steering apparatus is provided with a rack guide made of synthetic resin. In the outer periphery of the rack guide, peripheral ribs are formed in the direction of its circumference and axial ribs are formed in its longitudinal direction, respectively. The space formed between those ribs and the inner periphery of a guide bore of the rack guide is set to be generally about the same as the space between a conventional rack guide made of sintered alloy and the inner periphery of the guide bore. As a result, at room temperature, each rib enables the same press performance as the conventional rack guide and the suitable reacting force at steering will be kept. Also at high temperature atmosphere, when each rib thermally expands and abuts the guide bore, the outer periphery excluding the portions of the ribs is thermally expanded, thus, thermal creep is prevented and stable engagement of the rack and pinion of the steering apparatus can be maintained at all times.

Abstract: In a well pumping unit of the type employing a polished rod, a stuffing box is disposed at the upper end of the wellhead which has axially spaced bearing assemblies, and packing coils positioned between a bearing section at either end of each assembly to guide the polished rod for reciprocal movement along a vertical path through the wellhead, each bearing section having annular portions connected together in end-to-end relation with one portion composed of brass and another portion composed of zinc which is capable of undergoing a reduction reaction with the oxygen present in the liquids and gases to effectively reduce corrosion of the polished rod.

Abstract: A sliding unit adjustable within wide limits for operating machines comprising at least one hollow guide made from an extruded structural shape installed inside supporting elements equipped with revolving elements, which cooperate with sliding surfaces of the hollow guide, with the support elements being positioned on portions of a base plate which can be adjusted both in height, and in the transversal direction relatively to said hollow guide.

Abstract: A stationary guide plate (11) is formed with two locally intersecting profiled grooves (12, 13), which are profiled in conformity with a kinked path having a first and a second path section which are inclined relative to each other and of which a first groove (12) has a smaller width and a greater depth than a second groove (13). The profiled grooves (12, 13) are engaged by guide members (14, 15) which are connected to the object carrier (22) so as to be movable in the profiled grooves, and which have a transverse dimension corresponding at least substantially to the width of the respective profiled grooves.